1 // statements.cc -- Go frontend statements.
3 // Copyright 2009 The Go Authors. All rights reserved.
4 // Use of this source code is governed by a BSD-style
5 // license that can be found in the LICENSE file.
10 #include "go-diagnostics.h"
12 #include "expressions.h"
16 #include "statements.h"
21 Statement::Statement(Statement_classification classification
,
23 : classification_(classification
), location_(location
)
27 Statement::~Statement()
31 // Traverse the tree. The work of walking the components is handled
35 Statement::traverse(Block
* block
, size_t* pindex
, Traverse
* traverse
)
37 if (this->classification_
== STATEMENT_ERROR
)
38 return TRAVERSE_CONTINUE
;
40 unsigned int traverse_mask
= traverse
->traverse_mask();
42 if ((traverse_mask
& Traverse::traverse_statements
) != 0)
44 int t
= traverse
->statement(block
, pindex
, this);
45 if (t
== TRAVERSE_EXIT
)
47 else if (t
== TRAVERSE_SKIP_COMPONENTS
)
48 return TRAVERSE_CONTINUE
;
51 // No point in checking traverse_mask here--a statement may contain
52 // other blocks or statements, and if we got here we always want to
54 return this->do_traverse(traverse
);
57 // Traverse the contents of a statement.
60 Statement::traverse_contents(Traverse
* traverse
)
62 return this->do_traverse(traverse
);
65 // Traverse assignments.
68 Statement::traverse_assignments(Traverse_assignments
* tassign
)
70 if (this->classification_
== STATEMENT_ERROR
)
72 return this->do_traverse_assignments(tassign
);
75 // Traverse an expression in a statement. This is a helper function
79 Statement::traverse_expression(Traverse
* traverse
, Expression
** expr
)
81 if ((traverse
->traverse_mask()
82 & (Traverse::traverse_types
| Traverse::traverse_expressions
)) == 0)
83 return TRAVERSE_CONTINUE
;
84 return Expression::traverse(expr
, traverse
);
87 // Traverse an expression list in a statement. This is a helper
88 // function for child classes.
91 Statement::traverse_expression_list(Traverse
* traverse
,
92 Expression_list
* expr_list
)
94 if (expr_list
== NULL
)
95 return TRAVERSE_CONTINUE
;
96 if ((traverse
->traverse_mask()
97 & (Traverse::traverse_types
| Traverse::traverse_expressions
)) == 0)
98 return TRAVERSE_CONTINUE
;
99 return expr_list
->traverse(traverse
);
102 // Traverse a type in a statement. This is a helper function for
106 Statement::traverse_type(Traverse
* traverse
, Type
* type
)
108 if ((traverse
->traverse_mask()
109 & (Traverse::traverse_types
| Traverse::traverse_expressions
)) == 0)
110 return TRAVERSE_CONTINUE
;
111 return Type::traverse(type
, traverse
);
114 // Set type information for unnamed constants. This is really done by
118 Statement::determine_types()
120 this->do_determine_types();
123 // If this is a thunk statement, return it.
126 Statement::thunk_statement()
128 Thunk_statement
* ret
= this->convert
<Thunk_statement
, STATEMENT_GO
>();
130 ret
= this->convert
<Thunk_statement
, STATEMENT_DEFER
>();
134 // Convert a Statement to the backend representation. This is really
135 // done by the child class.
138 Statement::get_backend(Translate_context
* context
)
140 if (this->classification_
== STATEMENT_ERROR
)
141 return context
->backend()->error_statement();
142 return this->do_get_backend(context
);
145 // Dump AST representation for a statement to a dump context.
148 Statement::dump_statement(Ast_dump_context
* ast_dump_context
) const
150 this->do_dump_statement(ast_dump_context
);
153 // Note that this statement is erroneous. This is called by children
154 // when they discover an error.
157 Statement::set_is_error()
159 this->classification_
= STATEMENT_ERROR
;
162 // For children to call to report an error conveniently.
165 Statement::report_error(const char* msg
)
167 go_error_at(this->location_
, "%s", msg
);
168 this->set_is_error();
171 // An error statement, used to avoid crashing after we report an
174 class Error_statement
: public Statement
177 Error_statement(Location location
)
178 : Statement(STATEMENT_ERROR
, location
)
183 do_traverse(Traverse
*)
184 { return TRAVERSE_CONTINUE
; }
187 do_get_backend(Translate_context
*)
188 { go_unreachable(); }
191 do_dump_statement(Ast_dump_context
*) const;
195 // Helper to tack on available source position information
196 // at the end of a statement.
199 dsuffix(Location location
)
201 std::string lstr
= Linemap::location_to_string(location
);
204 std::string
rval(" // ");
209 // Dump the AST representation for an error statement.
212 Error_statement::do_dump_statement(Ast_dump_context
* ast_dump_context
) const
214 ast_dump_context
->print_indent();
215 ast_dump_context
->ostream() << "Error statement" << std::endl
;
218 // Make an error statement.
221 Statement::make_error_statement(Location location
)
223 return new Error_statement(location
);
226 // Class Variable_declaration_statement.
228 Variable_declaration_statement::Variable_declaration_statement(
230 : Statement(STATEMENT_VARIABLE_DECLARATION
, var
->var_value()->location()),
235 // We don't actually traverse the variable here; it was traversed
236 // while traversing the Block.
239 Variable_declaration_statement::do_traverse(Traverse
*)
241 return TRAVERSE_CONTINUE
;
244 // Traverse the assignments in a variable declaration. Note that this
245 // traversal is different from the usual traversal.
248 Variable_declaration_statement::do_traverse_assignments(
249 Traverse_assignments
* tassign
)
251 tassign
->initialize_variable(this->var_
);
255 // Lower the variable's initialization expression.
258 Variable_declaration_statement::do_lower(Gogo
* gogo
, Named_object
* function
,
259 Block
*, Statement_inserter
* inserter
)
261 this->var_
->var_value()->lower_init_expression(gogo
, function
, inserter
);
265 // Flatten the variable's initialization expression.
268 Variable_declaration_statement::do_flatten(Gogo
* gogo
, Named_object
* function
,
269 Block
*, Statement_inserter
* inserter
)
271 Variable
* var
= this->var_
->var_value();
272 if (var
->type()->is_error_type()
273 || (var
->init() != NULL
274 && var
->init()->is_error_expression()))
276 go_assert(saw_errors());
277 return Statement::make_error_statement(this->location());
279 this->var_
->var_value()->flatten_init_expression(gogo
, function
, inserter
);
283 // Convert a variable declaration to the backend representation.
286 Variable_declaration_statement::do_get_backend(Translate_context
* context
)
288 Bfunction
* bfunction
= context
->function()->func_value()->get_decl();
289 Variable
* var
= this->var_
->var_value();
290 Bvariable
* bvar
= this->var_
->get_backend_variable(context
->gogo(),
291 context
->function());
292 Bexpression
* binit
= var
->get_init(context
->gogo(), context
->function());
294 if (!var
->is_in_heap())
296 go_assert(binit
!= NULL
);
297 return context
->backend()->init_statement(bfunction
, bvar
, binit
);
300 // Something takes the address of this variable, so the value is
301 // stored in the heap. Initialize it to newly allocated memory
302 // space, and assign the initial value to the new space.
303 Location loc
= this->location();
304 Named_object
* newfn
= context
->gogo()->lookup_global("new");
305 go_assert(newfn
!= NULL
&& newfn
->is_function_declaration());
306 Expression
* func
= Expression::make_func_reference(newfn
, NULL
, loc
);
307 Expression_list
* params
= new Expression_list();
308 params
->push_back(Expression::make_type(var
->type(), loc
));
309 Expression
* call
= Expression::make_call(func
, params
, false, loc
);
310 context
->gogo()->lower_expression(context
->function(), NULL
, &call
);
311 Temporary_statement
* temp
= Statement::make_temporary(NULL
, call
, loc
);
312 Bstatement
* btemp
= temp
->get_backend(context
);
314 Bstatement
* set
= NULL
;
317 Expression
* e
= Expression::make_temporary_reference(temp
, loc
);
318 e
= Expression::make_dereference(e
, Expression::NIL_CHECK_NOT_NEEDED
,
320 Bexpression
* be
= e
->get_backend(context
);
321 set
= context
->backend()->assignment_statement(bfunction
, be
, binit
, loc
);
324 Expression
* ref
= Expression::make_temporary_reference(temp
, loc
);
325 Bexpression
* bref
= ref
->get_backend(context
);
326 Bstatement
* sinit
= context
->backend()->init_statement(bfunction
, bvar
, bref
);
328 std::vector
<Bstatement
*> stats
;
330 stats
.push_back(btemp
);
332 stats
.push_back(set
);
333 stats
.push_back(sinit
);
334 return context
->backend()->statement_list(stats
);
337 // Dump the AST representation for a variable declaration.
340 Variable_declaration_statement::do_dump_statement(
341 Ast_dump_context
* ast_dump_context
) const
343 ast_dump_context
->print_indent();
345 go_assert(var_
->is_variable());
346 ast_dump_context
->ostream() << "var " << this->var_
->name() << " ";
347 Variable
* var
= this->var_
->var_value();
350 ast_dump_context
->dump_type(var
->type());
351 ast_dump_context
->ostream() << " ";
353 if (var
->init() != NULL
)
355 ast_dump_context
->ostream() << "= ";
356 ast_dump_context
->dump_expression(var
->init());
358 ast_dump_context
->ostream() << dsuffix(location()) << std::endl
;
361 // Make a variable declaration.
364 Statement::make_variable_declaration(Named_object
* var
)
366 return new Variable_declaration_statement(var
);
369 // Class Temporary_statement.
371 // Return the type of the temporary variable.
374 Temporary_statement::type() const
376 Type
* type
= this->type_
!= NULL
? this->type_
: this->init_
->type();
378 // Temporary variables cannot have a void type.
379 if (type
->is_void_type())
381 go_assert(saw_errors());
382 return Type::make_error_type();
390 Temporary_statement::do_traverse(Traverse
* traverse
)
392 if (this->type_
!= NULL
393 && this->traverse_type(traverse
, this->type_
) == TRAVERSE_EXIT
)
394 return TRAVERSE_EXIT
;
395 if (this->init_
== NULL
)
396 return TRAVERSE_CONTINUE
;
398 return this->traverse_expression(traverse
, &this->init_
);
401 // Traverse assignments.
404 Temporary_statement::do_traverse_assignments(Traverse_assignments
* tassign
)
406 if (this->init_
== NULL
)
408 tassign
->value(&this->init_
, true, true);
415 Temporary_statement::do_determine_types()
417 if (this->type_
!= NULL
&& this->type_
->is_abstract())
418 this->type_
= this->type_
->make_non_abstract_type();
420 if (this->init_
!= NULL
)
422 if (this->type_
== NULL
)
423 this->init_
->determine_type_no_context();
426 Type_context
context(this->type_
, false);
427 this->init_
->determine_type(&context
);
431 if (this->type_
== NULL
)
433 this->type_
= this->init_
->type();
434 go_assert(!this->type_
->is_abstract());
441 Temporary_statement::do_check_types(Gogo
*)
443 if (this->type_
!= NULL
&& this->init_
!= NULL
)
446 if (!Type::are_assignable(this->type_
, this->init_
->type(), &reason
))
449 go_error_at(this->location(), "incompatible types in assignment");
451 go_error_at(this->location(), "incompatible types in assignment (%s)",
453 this->set_is_error();
458 // Flatten a temporary statement: add another temporary when it might
459 // be needed for interface conversion.
462 Temporary_statement::do_flatten(Gogo
*, Named_object
*, Block
*,
463 Statement_inserter
* inserter
)
465 if (this->type()->is_error_type()
466 || (this->init_
!= NULL
467 && this->init_
->is_error_expression()))
469 go_assert(saw_errors());
470 return Statement::make_error_statement(this->location());
473 if (this->type_
!= NULL
474 && this->init_
!= NULL
475 && !Type::are_identical(this->type_
, this->init_
->type(), false, NULL
)
476 && this->init_
->type()->interface_type() != NULL
477 && !this->init_
->is_variable())
479 Temporary_statement
*temp
=
480 Statement::make_temporary(NULL
, this->init_
, this->location());
481 inserter
->insert(temp
);
482 this->init_
= Expression::make_temporary_reference(temp
,
488 // Convert to backend representation.
491 Temporary_statement::do_get_backend(Translate_context
* context
)
493 go_assert(this->bvariable_
== NULL
);
495 Named_object
* function
= context
->function();
496 go_assert(function
!= NULL
);
497 Bfunction
* bfunction
= function
->func_value()->get_decl();
498 Btype
* btype
= this->type()->get_backend(context
->gogo());
501 if (this->init_
== NULL
)
503 else if (this->type_
== NULL
)
504 binit
= this->init_
->get_backend(context
);
507 Expression
* init
= Expression::convert_for_assignment(context
->gogo(),
511 binit
= init
->get_backend(context
);
515 binit
= context
->backend()->convert_expression(btype
, binit
,
518 Bstatement
* statement
;
520 context
->backend()->temporary_variable(bfunction
, context
->bblock(),
522 this->is_address_taken_
,
523 this->location(), &statement
);
527 // Return the backend variable.
530 Temporary_statement::get_backend_variable(Translate_context
* context
) const
532 if (this->bvariable_
== NULL
)
534 go_assert(saw_errors());
535 return context
->backend()->error_variable();
537 return this->bvariable_
;
540 // Dump the AST represemtation for a temporary statement
543 Temporary_statement::do_dump_statement(Ast_dump_context
* ast_dump_context
) const
545 ast_dump_context
->print_indent();
546 ast_dump_context
->dump_temp_variable_name(this);
547 if (this->type_
!= NULL
)
549 ast_dump_context
->ostream() << " ";
550 ast_dump_context
->dump_type(this->type_
);
552 if (this->init_
!= NULL
)
554 ast_dump_context
->ostream() << " = ";
555 ast_dump_context
->dump_expression(this->init_
);
557 ast_dump_context
->ostream() << dsuffix(location()) << std::endl
;
560 // Make and initialize a temporary variable in BLOCK.
563 Statement::make_temporary(Type
* type
, Expression
* init
,
566 return new Temporary_statement(type
, init
, location
);
569 // The Move_subexpressions class is used to move all top-level
570 // subexpressions of an expression. This is used for things like
571 // index expressions in which we must evaluate the index value before
572 // it can be changed by a multiple assignment.
574 class Move_subexpressions
: public Traverse
577 Move_subexpressions(int skip
, Block
* block
)
578 : Traverse(traverse_expressions
),
579 skip_(skip
), block_(block
)
584 expression(Expression
**);
587 // The number of subexpressions to skip moving. This is used to
588 // avoid moving the array itself, as we only need to move the index.
590 // The block where new temporary variables should be added.
595 Move_subexpressions::expression(Expression
** pexpr
)
599 else if ((*pexpr
)->temporary_reference_expression() == NULL
600 && !(*pexpr
)->is_nil_expression()
601 && !(*pexpr
)->is_constant())
603 Location loc
= (*pexpr
)->location();
604 Temporary_statement
* temp
= Statement::make_temporary(NULL
, *pexpr
, loc
);
605 this->block_
->add_statement(temp
);
606 *pexpr
= Expression::make_temporary_reference(temp
, loc
);
608 // We only need to move top-level subexpressions.
609 return TRAVERSE_SKIP_COMPONENTS
;
612 // The Move_ordered_evals class is used to find any subexpressions of
613 // an expression that have an evaluation order dependency. It creates
614 // temporary variables to hold them.
616 class Move_ordered_evals
: public Traverse
619 Move_ordered_evals(Block
* block
)
620 : Traverse(traverse_expressions
),
626 expression(Expression
**);
629 // The block where new temporary variables should be added.
634 Move_ordered_evals::expression(Expression
** pexpr
)
636 // We have to look at subexpressions first.
637 if ((*pexpr
)->traverse_subexpressions(this) == TRAVERSE_EXIT
)
638 return TRAVERSE_EXIT
;
641 if ((*pexpr
)->must_eval_subexpressions_in_order(&i
))
643 Move_subexpressions
ms(i
, this->block_
);
644 if ((*pexpr
)->traverse_subexpressions(&ms
) == TRAVERSE_EXIT
)
645 return TRAVERSE_EXIT
;
648 if ((*pexpr
)->must_eval_in_order())
650 Call_expression
* call
= (*pexpr
)->call_expression();
651 if (call
!= NULL
&& call
->is_multi_value_arg())
653 // A call expression which returns multiple results as an argument
654 // to another call must be handled specially. We can't create a
655 // temporary because there is no type to give it. Instead, group
656 // the caller and this multi-valued call argument and use a temporary
657 // variable to hold them.
658 return TRAVERSE_SKIP_COMPONENTS
;
661 Location loc
= (*pexpr
)->location();
662 Temporary_statement
* temp
= Statement::make_temporary(NULL
, *pexpr
, loc
);
663 this->block_
->add_statement(temp
);
664 *pexpr
= Expression::make_temporary_reference(temp
, loc
);
666 return TRAVERSE_SKIP_COMPONENTS
;
669 // Class Assignment_statement.
674 Assignment_statement::do_traverse(Traverse
* traverse
)
676 if (this->traverse_expression(traverse
, &this->lhs_
) == TRAVERSE_EXIT
)
677 return TRAVERSE_EXIT
;
678 return this->traverse_expression(traverse
, &this->rhs_
);
682 Assignment_statement::do_traverse_assignments(Traverse_assignments
* tassign
)
684 tassign
->assignment(&this->lhs_
, &this->rhs_
);
688 // Lower an assignment to a map index expression to a runtime function
692 Assignment_statement::do_lower(Gogo
*, Named_object
*, Block
* enclosing
,
695 Map_index_expression
* mie
= this->lhs_
->map_index_expression();
698 Location loc
= this->location();
700 Expression
* map
= mie
->map();
701 Map_type
* mt
= map
->type()->map_type();
704 go_assert(saw_errors());
705 return Statement::make_error_statement(loc
);
708 Block
* b
= new Block(enclosing
, loc
);
710 // Move out any subexpressions on the left hand side to make
711 // sure that functions are called in the required order.
712 Move_ordered_evals
moe(b
);
713 mie
->traverse_subexpressions(&moe
);
715 // Copy the key into a temporary so that we can take its address
716 // without pushing the value onto the heap.
718 // var key_temp KEY_TYPE = MAP_INDEX
719 Temporary_statement
* key_temp
= Statement::make_temporary(mt
->key_type(),
722 b
->add_statement(key_temp
);
724 // Copy the value into a temporary to ensure that it is
725 // evaluated before we add the key to the map. This may matter
726 // if the value is itself a reference to the map.
728 // var val_temp VAL_TYPE = RHS
729 Temporary_statement
* val_temp
= Statement::make_temporary(mt
->val_type(),
732 b
->add_statement(val_temp
);
734 // *mapassign(TYPE, MAP, &key_temp) = RHS
735 Expression
* a1
= Expression::make_type_descriptor(mt
, loc
);
736 Expression
* a2
= mie
->map();
737 Temporary_reference_expression
* ref
=
738 Expression::make_temporary_reference(key_temp
, loc
);
739 Expression
* a3
= Expression::make_unary(OPERATOR_AND
, ref
, loc
);
740 Expression
* call
= Runtime::make_call(Runtime::MAPASSIGN
, loc
, 3,
742 Type
* ptrval_type
= Type::make_pointer_type(mt
->val_type());
743 call
= Expression::make_cast(ptrval_type
, call
, loc
);
745 Expression::make_dereference(call
, Expression::NIL_CHECK_NOT_NEEDED
,
747 ref
= Expression::make_temporary_reference(val_temp
, loc
);
748 b
->add_statement(Statement::make_assignment(indir
, ref
, loc
));
750 return Statement::make_block_statement(b
, loc
);
756 // Set types for the assignment.
759 Assignment_statement::do_determine_types()
761 this->lhs_
->determine_type_no_context();
762 Type
* rhs_context_type
= this->lhs_
->type();
763 if (rhs_context_type
->is_sink_type())
764 rhs_context_type
= NULL
;
765 Type_context
context(rhs_context_type
, false);
766 this->rhs_
->determine_type(&context
);
769 // Check types for an assignment.
772 Assignment_statement::do_check_types(Gogo
*)
774 // The left hand side must be either addressable, a map index
775 // expression, or the blank identifier.
776 if (!this->lhs_
->is_addressable()
777 && this->lhs_
->map_index_expression() == NULL
778 && !this->lhs_
->is_sink_expression())
780 if (!this->lhs_
->type()->is_error())
781 this->report_error(_("invalid left hand side of assignment"));
785 Type
* lhs_type
= this->lhs_
->type();
786 Type
* rhs_type
= this->rhs_
->type();
788 // Invalid assignment of nil to the blank identifier.
789 if (lhs_type
->is_sink_type()
790 && rhs_type
->is_nil_type())
792 this->report_error(_("use of untyped nil"));
797 if (!Type::are_assignable(lhs_type
, rhs_type
, &reason
))
800 go_error_at(this->location(), "incompatible types in assignment");
802 go_error_at(this->location(), "incompatible types in assignment (%s)",
804 this->set_is_error();
807 if (lhs_type
->is_error() || rhs_type
->is_error())
808 this->set_is_error();
811 // Flatten an assignment statement. We may need a temporary for
812 // interface conversion.
815 Assignment_statement::do_flatten(Gogo
*, Named_object
*, Block
*,
816 Statement_inserter
* inserter
)
818 if (this->lhs_
->is_error_expression()
819 || this->lhs_
->type()->is_error_type()
820 || this->rhs_
->is_error_expression()
821 || this->rhs_
->type()->is_error_type())
823 go_assert(saw_errors());
824 return Statement::make_error_statement(this->location());
827 if (!this->lhs_
->is_sink_expression()
828 && !Type::are_identical(this->lhs_
->type(), this->rhs_
->type(),
830 && this->rhs_
->type()->interface_type() != NULL
831 && !this->rhs_
->is_variable())
833 Temporary_statement
* temp
=
834 Statement::make_temporary(NULL
, this->rhs_
, this->location());
835 inserter
->insert(temp
);
836 this->rhs_
= Expression::make_temporary_reference(temp
,
842 // Convert an assignment statement to the backend representation.
845 Assignment_statement::do_get_backend(Translate_context
* context
)
847 if (this->lhs_
->is_sink_expression())
849 Bexpression
* rhs
= this->rhs_
->get_backend(context
);
850 Bfunction
* bfunction
= context
->function()->func_value()->get_decl();
851 return context
->backend()->expression_statement(bfunction
, rhs
);
854 Bexpression
* lhs
= this->lhs_
->get_backend(context
);
856 Expression::convert_for_assignment(context
->gogo(), this->lhs_
->type(),
857 this->rhs_
, this->location());
858 Bexpression
* rhs
= conv
->get_backend(context
);
859 Bfunction
* bfunction
= context
->function()->func_value()->get_decl();
860 return context
->backend()->assignment_statement(bfunction
, lhs
, rhs
,
864 // Dump the AST representation for an assignment statement.
867 Assignment_statement::do_dump_statement(Ast_dump_context
* ast_dump_context
)
870 ast_dump_context
->print_indent();
871 ast_dump_context
->dump_expression(this->lhs_
);
872 ast_dump_context
->ostream() << " = " ;
873 ast_dump_context
->dump_expression(this->rhs_
);
874 ast_dump_context
->ostream() << dsuffix(location()) << std::endl
;
877 // Make an assignment statement.
880 Statement::make_assignment(Expression
* lhs
, Expression
* rhs
,
883 return new Assignment_statement(lhs
, rhs
, location
);
886 // An assignment operation statement.
888 class Assignment_operation_statement
: public Statement
891 Assignment_operation_statement(Operator op
, Expression
* lhs
, Expression
* rhs
,
893 : Statement(STATEMENT_ASSIGNMENT_OPERATION
, location
),
894 op_(op
), lhs_(lhs
), rhs_(rhs
)
899 do_traverse(Traverse
*);
902 do_traverse_assignments(Traverse_assignments
*)
903 { go_unreachable(); }
906 do_lower(Gogo
*, Named_object
*, Block
*, Statement_inserter
*);
909 do_get_backend(Translate_context
*)
910 { go_unreachable(); }
913 do_dump_statement(Ast_dump_context
*) const;
916 // The operator (OPERATOR_PLUSEQ, etc.).
927 Assignment_operation_statement::do_traverse(Traverse
* traverse
)
929 if (this->traverse_expression(traverse
, &this->lhs_
) == TRAVERSE_EXIT
)
930 return TRAVERSE_EXIT
;
931 return this->traverse_expression(traverse
, &this->rhs_
);
934 // Lower an assignment operation statement to a regular assignment
938 Assignment_operation_statement::do_lower(Gogo
*, Named_object
*,
939 Block
* enclosing
, Statement_inserter
*)
941 Location loc
= this->location();
943 // We have to evaluate the left hand side expression only once. We
944 // do this by moving out any expression with side effects.
945 Block
* b
= new Block(enclosing
, loc
);
946 Move_ordered_evals
moe(b
);
947 this->lhs_
->traverse_subexpressions(&moe
);
949 Expression
* lval
= this->lhs_
->copy();
954 case OPERATOR_PLUSEQ
:
957 case OPERATOR_MINUSEQ
:
966 case OPERATOR_MULTEQ
:
975 case OPERATOR_LSHIFTEQ
:
976 op
= OPERATOR_LSHIFT
;
978 case OPERATOR_RSHIFTEQ
:
979 op
= OPERATOR_RSHIFT
;
984 case OPERATOR_BITCLEAREQ
:
985 op
= OPERATOR_BITCLEAR
;
991 Expression
* binop
= Expression::make_binary(op
, lval
, this->rhs_
, loc
);
992 Statement
* s
= Statement::make_assignment(this->lhs_
, binop
, loc
);
993 if (b
->statements()->empty())
1000 b
->add_statement(s
);
1001 return Statement::make_block_statement(b
, loc
);
1005 // Dump the AST representation for an assignment operation statement
1008 Assignment_operation_statement::do_dump_statement(
1009 Ast_dump_context
* ast_dump_context
) const
1011 ast_dump_context
->print_indent();
1012 ast_dump_context
->dump_expression(this->lhs_
);
1013 ast_dump_context
->dump_operator(this->op_
);
1014 ast_dump_context
->dump_expression(this->rhs_
);
1015 ast_dump_context
->ostream() << dsuffix(location()) << std::endl
;
1018 // Make an assignment operation statement.
1021 Statement::make_assignment_operation(Operator op
, Expression
* lhs
,
1022 Expression
* rhs
, Location location
)
1024 return new Assignment_operation_statement(op
, lhs
, rhs
, location
);
1027 // A tuple assignment statement. This differs from an assignment
1028 // statement in that the right-hand-side expressions are evaluated in
1031 class Tuple_assignment_statement
: public Statement
1034 Tuple_assignment_statement(Expression_list
* lhs
, Expression_list
* rhs
,
1036 : Statement(STATEMENT_TUPLE_ASSIGNMENT
, location
),
1037 lhs_(lhs
), rhs_(rhs
)
1042 do_traverse(Traverse
* traverse
);
1045 do_traverse_assignments(Traverse_assignments
*)
1046 { go_unreachable(); }
1049 do_lower(Gogo
*, Named_object
*, Block
*, Statement_inserter
*);
1052 do_get_backend(Translate_context
*)
1053 { go_unreachable(); }
1056 do_dump_statement(Ast_dump_context
*) const;
1059 // Left hand side--a list of lvalues.
1060 Expression_list
* lhs_
;
1061 // Right hand side--a list of rvalues.
1062 Expression_list
* rhs_
;
1068 Tuple_assignment_statement::do_traverse(Traverse
* traverse
)
1070 if (this->traverse_expression_list(traverse
, this->lhs_
) == TRAVERSE_EXIT
)
1071 return TRAVERSE_EXIT
;
1072 return this->traverse_expression_list(traverse
, this->rhs_
);
1075 // Lower a tuple assignment. We use temporary variables to split it
1076 // up into a set of single assignments.
1079 Tuple_assignment_statement::do_lower(Gogo
*, Named_object
*, Block
* enclosing
,
1080 Statement_inserter
*)
1082 Location loc
= this->location();
1084 Block
* b
= new Block(enclosing
, loc
);
1086 // First move out any subexpressions on the left hand side. The
1087 // right hand side will be evaluated in the required order anyhow.
1088 Move_ordered_evals
moe(b
);
1089 for (Expression_list::iterator plhs
= this->lhs_
->begin();
1090 plhs
!= this->lhs_
->end();
1092 Expression::traverse(&*plhs
, &moe
);
1094 std::vector
<Temporary_statement
*> temps
;
1095 temps
.reserve(this->lhs_
->size());
1097 Expression_list::const_iterator prhs
= this->rhs_
->begin();
1098 for (Expression_list::const_iterator plhs
= this->lhs_
->begin();
1099 plhs
!= this->lhs_
->end();
1102 go_assert(prhs
!= this->rhs_
->end());
1104 if ((*plhs
)->is_error_expression()
1105 || (*plhs
)->type()->is_error()
1106 || (*prhs
)->is_error_expression()
1107 || (*prhs
)->type()->is_error())
1110 if ((*plhs
)->is_sink_expression())
1112 if ((*prhs
)->type()->is_nil_type())
1113 this->report_error(_("use of untyped nil"));
1115 b
->add_statement(Statement::make_statement(*prhs
, true));
1119 Temporary_statement
* temp
= Statement::make_temporary((*plhs
)->type(),
1121 b
->add_statement(temp
);
1122 temps
.push_back(temp
);
1125 go_assert(prhs
== this->rhs_
->end());
1127 prhs
= this->rhs_
->begin();
1128 std::vector
<Temporary_statement
*>::const_iterator ptemp
= temps
.begin();
1129 for (Expression_list::const_iterator plhs
= this->lhs_
->begin();
1130 plhs
!= this->lhs_
->end();
1133 if ((*plhs
)->is_error_expression()
1134 || (*plhs
)->type()->is_error()
1135 || (*prhs
)->is_error_expression()
1136 || (*prhs
)->type()->is_error())
1139 if ((*plhs
)->is_sink_expression())
1142 Expression
* ref
= Expression::make_temporary_reference(*ptemp
, loc
);
1143 b
->add_statement(Statement::make_assignment(*plhs
, ref
, loc
));
1146 go_assert(ptemp
== temps
.end() || saw_errors());
1148 return Statement::make_block_statement(b
, loc
);
1151 // Dump the AST representation for a tuple assignment statement.
1154 Tuple_assignment_statement::do_dump_statement(
1155 Ast_dump_context
* ast_dump_context
) const
1157 ast_dump_context
->print_indent();
1158 ast_dump_context
->dump_expression_list(this->lhs_
);
1159 ast_dump_context
->ostream() << " = ";
1160 ast_dump_context
->dump_expression_list(this->rhs_
);
1161 ast_dump_context
->ostream() << dsuffix(location()) << std::endl
;
1164 // Make a tuple assignment statement.
1167 Statement::make_tuple_assignment(Expression_list
* lhs
, Expression_list
* rhs
,
1170 return new Tuple_assignment_statement(lhs
, rhs
, location
);
1173 // A tuple assignment from a map index expression.
1176 class Tuple_map_assignment_statement
: public Statement
1179 Tuple_map_assignment_statement(Expression
* val
, Expression
* present
,
1180 Expression
* map_index
,
1182 : Statement(STATEMENT_TUPLE_MAP_ASSIGNMENT
, location
),
1183 val_(val
), present_(present
), map_index_(map_index
)
1188 do_traverse(Traverse
* traverse
);
1191 do_traverse_assignments(Traverse_assignments
*)
1192 { go_unreachable(); }
1195 do_lower(Gogo
*, Named_object
*, Block
*, Statement_inserter
*);
1198 do_get_backend(Translate_context
*)
1199 { go_unreachable(); }
1202 do_dump_statement(Ast_dump_context
*) const;
1205 // Lvalue which receives the value from the map.
1207 // Lvalue which receives whether the key value was present.
1208 Expression
* present_
;
1209 // The map index expression.
1210 Expression
* map_index_
;
1216 Tuple_map_assignment_statement::do_traverse(Traverse
* traverse
)
1218 if (this->traverse_expression(traverse
, &this->val_
) == TRAVERSE_EXIT
1219 || this->traverse_expression(traverse
, &this->present_
) == TRAVERSE_EXIT
)
1220 return TRAVERSE_EXIT
;
1221 return this->traverse_expression(traverse
, &this->map_index_
);
1224 // Lower a tuple map assignment.
1227 Tuple_map_assignment_statement::do_lower(Gogo
* gogo
, Named_object
*,
1228 Block
* enclosing
, Statement_inserter
*)
1230 Location loc
= this->location();
1232 Map_index_expression
* map_index
= this->map_index_
->map_index_expression();
1233 if (map_index
== NULL
)
1235 this->report_error(_("expected map index on right hand side"));
1236 return Statement::make_error_statement(loc
);
1238 Map_type
* map_type
= map_index
->get_map_type();
1239 if (map_type
== NULL
)
1240 return Statement::make_error_statement(loc
);
1242 Block
* b
= new Block(enclosing
, loc
);
1244 // Move out any subexpressions to make sure that functions are
1245 // called in the required order.
1246 Move_ordered_evals
moe(b
);
1247 this->val_
->traverse_subexpressions(&moe
);
1248 this->present_
->traverse_subexpressions(&moe
);
1250 // Copy the key value into a temporary so that we can take its
1251 // address without pushing the value onto the heap.
1253 // var key_temp KEY_TYPE = MAP_INDEX
1254 Temporary_statement
* key_temp
=
1255 Statement::make_temporary(map_type
->key_type(), map_index
->index(), loc
);
1256 b
->add_statement(key_temp
);
1258 // var val_ptr_temp *VAL_TYPE
1259 Type
* val_ptr_type
= Type::make_pointer_type(map_type
->val_type());
1260 Temporary_statement
* val_ptr_temp
= Statement::make_temporary(val_ptr_type
,
1262 b
->add_statement(val_ptr_temp
);
1264 // var present_temp bool
1265 Temporary_statement
* present_temp
=
1266 Statement::make_temporary((this->present_
->type()->is_sink_type())
1267 ? Type::make_boolean_type()
1268 : this->present_
->type(),
1270 b
->add_statement(present_temp
);
1272 // val_ptr_temp, present_temp = mapaccess2(DESCRIPTOR, MAP, &key_temp)
1273 Expression
* a1
= Expression::make_type_descriptor(map_type
, loc
);
1274 Expression
* a2
= map_index
->map();
1275 Temporary_reference_expression
* ref
=
1276 Expression::make_temporary_reference(key_temp
, loc
);
1277 Expression
* a3
= Expression::make_unary(OPERATOR_AND
, ref
, loc
);
1278 Expression
* a4
= map_type
->fat_zero_value(gogo
);
1279 Call_expression
* call
;
1281 call
= Runtime::make_call(Runtime::MAPACCESS2
, loc
, 3, a1
, a2
, a3
);
1283 call
= Runtime::make_call(Runtime::MAPACCESS2_FAT
, loc
, 4, a1
, a2
, a3
, a4
);
1284 ref
= Expression::make_temporary_reference(val_ptr_temp
, loc
);
1285 ref
->set_is_lvalue();
1286 Expression
* res
= Expression::make_call_result(call
, 0);
1287 res
= Expression::make_unsafe_cast(val_ptr_type
, res
, loc
);
1288 Statement
* s
= Statement::make_assignment(ref
, res
, loc
);
1289 b
->add_statement(s
);
1290 ref
= Expression::make_temporary_reference(present_temp
, loc
);
1291 ref
->set_is_lvalue();
1292 res
= Expression::make_call_result(call
, 1);
1293 s
= Statement::make_assignment(ref
, res
, loc
);
1294 b
->add_statement(s
);
1296 // val = *val__ptr_temp
1297 ref
= Expression::make_temporary_reference(val_ptr_temp
, loc
);
1299 Expression::make_dereference(ref
, Expression::NIL_CHECK_NOT_NEEDED
, loc
);
1300 s
= Statement::make_assignment(this->val_
, ind
, loc
);
1301 b
->add_statement(s
);
1303 // present = present_temp
1304 ref
= Expression::make_temporary_reference(present_temp
, loc
);
1305 s
= Statement::make_assignment(this->present_
, ref
, loc
);
1306 b
->add_statement(s
);
1308 return Statement::make_block_statement(b
, loc
);
1311 // Dump the AST representation for a tuple map assignment statement.
1314 Tuple_map_assignment_statement::do_dump_statement(
1315 Ast_dump_context
* ast_dump_context
) const
1317 ast_dump_context
->print_indent();
1318 ast_dump_context
->dump_expression(this->val_
);
1319 ast_dump_context
->ostream() << ", ";
1320 ast_dump_context
->dump_expression(this->present_
);
1321 ast_dump_context
->ostream() << " = ";
1322 ast_dump_context
->dump_expression(this->map_index_
);
1323 ast_dump_context
->ostream() << dsuffix(location()) << std::endl
;
1326 // Make a map assignment statement which returns a pair of values.
1329 Statement::make_tuple_map_assignment(Expression
* val
, Expression
* present
,
1330 Expression
* map_index
,
1333 return new Tuple_map_assignment_statement(val
, present
, map_index
, location
);
1336 // A tuple assignment from a receive statement.
1338 class Tuple_receive_assignment_statement
: public Statement
1341 Tuple_receive_assignment_statement(Expression
* val
, Expression
* closed
,
1342 Expression
* channel
, Location location
)
1343 : Statement(STATEMENT_TUPLE_RECEIVE_ASSIGNMENT
, location
),
1344 val_(val
), closed_(closed
), channel_(channel
)
1349 do_traverse(Traverse
* traverse
);
1352 do_traverse_assignments(Traverse_assignments
*)
1353 { go_unreachable(); }
1356 do_lower(Gogo
*, Named_object
*, Block
*, Statement_inserter
*);
1359 do_get_backend(Translate_context
*)
1360 { go_unreachable(); }
1363 do_dump_statement(Ast_dump_context
*) const;
1366 // Lvalue which receives the value from the channel.
1368 // Lvalue which receives whether the channel is closed.
1369 Expression
* closed_
;
1370 // The channel on which we receive the value.
1371 Expression
* channel_
;
1377 Tuple_receive_assignment_statement::do_traverse(Traverse
* traverse
)
1379 if (this->traverse_expression(traverse
, &this->val_
) == TRAVERSE_EXIT
1380 || this->traverse_expression(traverse
, &this->closed_
) == TRAVERSE_EXIT
)
1381 return TRAVERSE_EXIT
;
1382 return this->traverse_expression(traverse
, &this->channel_
);
1385 // Lower to a function call.
1388 Tuple_receive_assignment_statement::do_lower(Gogo
*, Named_object
*,
1390 Statement_inserter
*)
1392 Location loc
= this->location();
1394 Channel_type
* channel_type
= this->channel_
->type()->channel_type();
1395 if (channel_type
== NULL
)
1397 this->report_error(_("expected channel"));
1398 return Statement::make_error_statement(loc
);
1400 if (!channel_type
->may_receive())
1402 this->report_error(_("invalid receive on send-only channel"));
1403 return Statement::make_error_statement(loc
);
1406 Block
* b
= new Block(enclosing
, loc
);
1408 // Make sure that any subexpressions on the left hand side are
1409 // evaluated in the right order.
1410 Move_ordered_evals
moe(b
);
1411 this->val_
->traverse_subexpressions(&moe
);
1412 this->closed_
->traverse_subexpressions(&moe
);
1414 // var val_temp ELEMENT_TYPE
1415 Temporary_statement
* val_temp
=
1416 Statement::make_temporary(channel_type
->element_type(), NULL
, loc
);
1417 b
->add_statement(val_temp
);
1419 // var closed_temp bool
1420 Temporary_statement
* closed_temp
=
1421 Statement::make_temporary((this->closed_
->type()->is_sink_type())
1422 ? Type::make_boolean_type()
1423 : this->closed_
->type(),
1425 b
->add_statement(closed_temp
);
1427 // closed_temp = chanrecv2(channel, &val_temp)
1428 Temporary_reference_expression
* ref
=
1429 Expression::make_temporary_reference(val_temp
, loc
);
1430 Expression
* p2
= Expression::make_unary(OPERATOR_AND
, ref
, loc
);
1431 Expression
* call
= Runtime::make_call(Runtime::CHANRECV2
,
1432 loc
, 2, this->channel_
, p2
);
1433 ref
= Expression::make_temporary_reference(closed_temp
, loc
);
1434 ref
->set_is_lvalue();
1435 Statement
* s
= Statement::make_assignment(ref
, call
, loc
);
1436 b
->add_statement(s
);
1439 ref
= Expression::make_temporary_reference(val_temp
, loc
);
1440 s
= Statement::make_assignment(this->val_
, ref
, loc
);
1441 b
->add_statement(s
);
1443 // closed = closed_temp
1444 ref
= Expression::make_temporary_reference(closed_temp
, loc
);
1445 s
= Statement::make_assignment(this->closed_
, ref
, loc
);
1446 b
->add_statement(s
);
1448 return Statement::make_block_statement(b
, loc
);
1451 // Dump the AST representation for a tuple receive statement.
1454 Tuple_receive_assignment_statement::do_dump_statement(
1455 Ast_dump_context
* ast_dump_context
) const
1457 ast_dump_context
->print_indent();
1458 ast_dump_context
->dump_expression(this->val_
);
1459 ast_dump_context
->ostream() << ", ";
1460 ast_dump_context
->dump_expression(this->closed_
);
1461 ast_dump_context
->ostream() << " <- ";
1462 ast_dump_context
->dump_expression(this->channel_
);
1463 ast_dump_context
->ostream() << dsuffix(location()) << std::endl
;
1466 // Make a nonblocking receive statement.
1469 Statement::make_tuple_receive_assignment(Expression
* val
, Expression
* closed
,
1470 Expression
* channel
,
1473 return new Tuple_receive_assignment_statement(val
, closed
, channel
,
1477 // An assignment to a pair of values from a type guard. This is a
1478 // conditional type guard. v, ok = i.(type).
1480 class Tuple_type_guard_assignment_statement
: public Statement
1483 Tuple_type_guard_assignment_statement(Expression
* val
, Expression
* ok
,
1484 Expression
* expr
, Type
* type
,
1486 : Statement(STATEMENT_TUPLE_TYPE_GUARD_ASSIGNMENT
, location
),
1487 val_(val
), ok_(ok
), expr_(expr
), type_(type
)
1492 do_traverse(Traverse
*);
1495 do_traverse_assignments(Traverse_assignments
*)
1496 { go_unreachable(); }
1499 do_lower(Gogo
*, Named_object
*, Block
*, Statement_inserter
*);
1502 do_get_backend(Translate_context
*)
1503 { go_unreachable(); }
1506 do_dump_statement(Ast_dump_context
*) const;
1510 lower_to_type(Runtime::Function
);
1513 lower_to_object_type(Block
*, Runtime::Function
);
1515 // The variable which recieves the converted value.
1517 // The variable which receives the indication of success.
1519 // The expression being converted.
1521 // The type to which the expression is being converted.
1525 // Traverse a type guard tuple assignment.
1528 Tuple_type_guard_assignment_statement::do_traverse(Traverse
* traverse
)
1530 if (this->traverse_expression(traverse
, &this->val_
) == TRAVERSE_EXIT
1531 || this->traverse_expression(traverse
, &this->ok_
) == TRAVERSE_EXIT
1532 || this->traverse_type(traverse
, this->type_
) == TRAVERSE_EXIT
)
1533 return TRAVERSE_EXIT
;
1534 return this->traverse_expression(traverse
, &this->expr_
);
1537 // Lower to a function call.
1540 Tuple_type_guard_assignment_statement::do_lower(Gogo
*, Named_object
*,
1542 Statement_inserter
*)
1544 Location loc
= this->location();
1546 Type
* expr_type
= this->expr_
->type();
1547 if (expr_type
->interface_type() == NULL
)
1549 if (!expr_type
->is_error() && !this->type_
->is_error())
1550 this->report_error(_("type assertion only valid for interface types"));
1551 return Statement::make_error_statement(loc
);
1554 Block
* b
= new Block(enclosing
, loc
);
1556 // Make sure that any subexpressions on the left hand side are
1557 // evaluated in the right order.
1558 Move_ordered_evals
moe(b
);
1559 this->val_
->traverse_subexpressions(&moe
);
1560 this->ok_
->traverse_subexpressions(&moe
);
1562 bool expr_is_empty
= expr_type
->interface_type()->is_empty();
1563 Call_expression
* call
;
1564 if (this->type_
->interface_type() != NULL
)
1566 if (this->type_
->interface_type()->is_empty())
1567 call
= Runtime::make_call((expr_is_empty
1568 ? Runtime::IFACEE2E2
1569 : Runtime::IFACEI2E2
),
1570 loc
, 1, this->expr_
);
1572 call
= this->lower_to_type(expr_is_empty
1573 ? Runtime::IFACEE2I2
1574 : Runtime::IFACEI2I2
);
1576 else if (this->type_
->points_to() != NULL
)
1577 call
= this->lower_to_type(expr_is_empty
1578 ? Runtime::IFACEE2T2P
1579 : Runtime::IFACEI2T2P
);
1582 this->lower_to_object_type(b
,
1584 ? Runtime::IFACEE2T2
1585 : Runtime::IFACEI2T2
));
1591 Expression
* res
= Expression::make_call_result(call
, 0);
1592 res
= Expression::make_unsafe_cast(this->type_
, res
, loc
);
1593 Statement
* s
= Statement::make_assignment(this->val_
, res
, loc
);
1594 b
->add_statement(s
);
1596 res
= Expression::make_call_result(call
, 1);
1597 s
= Statement::make_assignment(this->ok_
, res
, loc
);
1598 b
->add_statement(s
);
1601 return Statement::make_block_statement(b
, loc
);
1604 // Lower a conversion to a non-empty interface type or a pointer type.
1607 Tuple_type_guard_assignment_statement::lower_to_type(Runtime::Function code
)
1609 Location loc
= this->location();
1610 return Runtime::make_call(code
, loc
, 2,
1611 Expression::make_type_descriptor(this->type_
, loc
),
1615 // Lower a conversion to a non-interface non-pointer type.
1618 Tuple_type_guard_assignment_statement::lower_to_object_type(
1620 Runtime::Function code
)
1622 Location loc
= this->location();
1624 // var val_temp TYPE
1625 Temporary_statement
* val_temp
= Statement::make_temporary(this->type_
,
1627 b
->add_statement(val_temp
);
1629 // ok = CODE(type_descriptor, expr, &val_temp)
1630 Expression
* p1
= Expression::make_type_descriptor(this->type_
, loc
);
1631 Expression
* ref
= Expression::make_temporary_reference(val_temp
, loc
);
1632 Expression
* p3
= Expression::make_unary(OPERATOR_AND
, ref
, loc
);
1633 Expression
* call
= Runtime::make_call(code
, loc
, 3, p1
, this->expr_
, p3
);
1634 Statement
* s
= Statement::make_assignment(this->ok_
, call
, loc
);
1635 b
->add_statement(s
);
1638 ref
= Expression::make_temporary_reference(val_temp
, loc
);
1639 s
= Statement::make_assignment(this->val_
, ref
, loc
);
1640 b
->add_statement(s
);
1643 // Dump the AST representation for a tuple type guard statement.
1646 Tuple_type_guard_assignment_statement::do_dump_statement(
1647 Ast_dump_context
* ast_dump_context
) const
1649 ast_dump_context
->print_indent();
1650 ast_dump_context
->dump_expression(this->val_
);
1651 ast_dump_context
->ostream() << ", ";
1652 ast_dump_context
->dump_expression(this->ok_
);
1653 ast_dump_context
->ostream() << " = ";
1654 ast_dump_context
->dump_expression(this->expr_
);
1655 ast_dump_context
->ostream() << " . ";
1656 ast_dump_context
->dump_type(this->type_
);
1657 ast_dump_context
->ostream() << dsuffix(location()) << std::endl
;
1660 // Make an assignment from a type guard to a pair of variables.
1663 Statement::make_tuple_type_guard_assignment(Expression
* val
, Expression
* ok
,
1664 Expression
* expr
, Type
* type
,
1667 return new Tuple_type_guard_assignment_statement(val
, ok
, expr
, type
,
1671 // Class Expression_statement.
1675 Expression_statement::Expression_statement(Expression
* expr
, bool is_ignored
)
1676 : Statement(STATEMENT_EXPRESSION
, expr
->location()),
1677 expr_(expr
), is_ignored_(is_ignored
)
1684 Expression_statement::do_determine_types()
1686 this->expr_
->determine_type_no_context();
1689 // Check the types of an expression statement. The only check we do
1690 // is to possibly give an error about discarding the value of the
1694 Expression_statement::do_check_types(Gogo
*)
1696 if (!this->is_ignored_
)
1697 this->expr_
->discarding_value();
1700 // An expression statement is only a terminating statement if it is
1704 Expression_statement::do_may_fall_through() const
1706 const Call_expression
* call
= this->expr_
->call_expression();
1709 const Expression
* fn
= call
->fn();
1710 // panic is still an unknown named object.
1711 const Unknown_expression
* ue
= fn
->unknown_expression();
1714 Named_object
* no
= ue
->named_object();
1716 if (no
->is_unknown())
1717 no
= no
->unknown_value()->real_named_object();
1720 Function_type
* fntype
;
1721 if (no
->is_function())
1722 fntype
= no
->func_value()->type();
1723 else if (no
->is_function_declaration())
1724 fntype
= no
->func_declaration_value()->type();
1728 // The builtin function panic does not return.
1729 if (fntype
!= NULL
&& fntype
->is_builtin() && no
->name() == "panic")
1737 // Convert to backend representation.
1740 Expression_statement::do_get_backend(Translate_context
* context
)
1742 Bexpression
* bexpr
= this->expr_
->get_backend(context
);
1743 Bfunction
* bfunction
= context
->function()->func_value()->get_decl();
1744 return context
->backend()->expression_statement(bfunction
, bexpr
);
1747 // Dump the AST representation for an expression statement
1750 Expression_statement::do_dump_statement(Ast_dump_context
* ast_dump_context
)
1753 ast_dump_context
->print_indent();
1754 ast_dump_context
->dump_expression(expr_
);
1755 ast_dump_context
->ostream() << dsuffix(location()) << std::endl
;
1758 // Make an expression statement from an Expression.
1761 Statement::make_statement(Expression
* expr
, bool is_ignored
)
1763 return new Expression_statement(expr
, is_ignored
);
1766 // Convert a block to the backend representation of a statement.
1769 Block_statement::do_get_backend(Translate_context
* context
)
1771 Bblock
* bblock
= this->block_
->get_backend(context
);
1772 return context
->backend()->block_statement(bblock
);
1775 // Dump the AST for a block statement
1778 Block_statement::do_dump_statement(Ast_dump_context
*) const
1780 // block statement braces are dumped when traversing.
1783 // Make a block statement.
1786 Statement::make_block_statement(Block
* block
, Location location
)
1788 return new Block_statement(block
, location
);
1791 // An increment or decrement statement.
1793 class Inc_dec_statement
: public Statement
1796 Inc_dec_statement(bool is_inc
, Expression
* expr
)
1797 : Statement(STATEMENT_INCDEC
, expr
->location()),
1798 expr_(expr
), is_inc_(is_inc
)
1803 do_traverse(Traverse
* traverse
)
1804 { return this->traverse_expression(traverse
, &this->expr_
); }
1807 do_traverse_assignments(Traverse_assignments
*)
1808 { go_unreachable(); }
1811 do_lower(Gogo
*, Named_object
*, Block
*, Statement_inserter
*);
1814 do_get_backend(Translate_context
*)
1815 { go_unreachable(); }
1818 do_dump_statement(Ast_dump_context
*) const;
1821 // The l-value to increment or decrement.
1823 // Whether to increment or decrement.
1827 // Lower to += or -=.
1830 Inc_dec_statement::do_lower(Gogo
*, Named_object
*, Block
*, Statement_inserter
*)
1832 Location loc
= this->location();
1833 if (!this->expr_
->type()->is_numeric_type())
1835 this->report_error("increment or decrement of non-numeric type");
1836 return Statement::make_error_statement(loc
);
1838 Expression
* oexpr
= Expression::make_integer_ul(1, this->expr_
->type(), loc
);
1839 Operator op
= this->is_inc_
? OPERATOR_PLUSEQ
: OPERATOR_MINUSEQ
;
1840 return Statement::make_assignment_operation(op
, this->expr_
, oexpr
, loc
);
1843 // Dump the AST representation for a inc/dec statement.
1846 Inc_dec_statement::do_dump_statement(Ast_dump_context
* ast_dump_context
) const
1848 ast_dump_context
->print_indent();
1849 ast_dump_context
->dump_expression(expr_
);
1850 ast_dump_context
->ostream() << (is_inc_
? "++": "--") << dsuffix(location()) << std::endl
;
1853 // Make an increment statement.
1856 Statement::make_inc_statement(Expression
* expr
)
1858 return new Inc_dec_statement(true, expr
);
1861 // Make a decrement statement.
1864 Statement::make_dec_statement(Expression
* expr
)
1866 return new Inc_dec_statement(false, expr
);
1869 // Class Thunk_statement. This is the base class for go and defer
1874 Thunk_statement::Thunk_statement(Statement_classification classification
,
1875 Call_expression
* call
,
1877 : Statement(classification
, location
),
1878 call_(call
), struct_type_(NULL
)
1882 // Return whether this is a simple statement which does not require a
1886 Thunk_statement::is_simple(Function_type
* fntype
) const
1888 // We need a thunk to call a method, or to pass a variable number of
1890 if (fntype
->is_method() || fntype
->is_varargs())
1893 // A defer statement requires a thunk to set up for whether the
1894 // function can call recover.
1895 if (this->classification() == STATEMENT_DEFER
)
1898 // We can only permit a single parameter of pointer type.
1899 const Typed_identifier_list
* parameters
= fntype
->parameters();
1900 if (parameters
!= NULL
1901 && (parameters
->size() > 1
1902 || (parameters
->size() == 1
1903 && parameters
->begin()->type()->points_to() == NULL
)))
1906 // If the function returns multiple values, or returns a type other
1907 // than integer, floating point, or pointer, then it may get a
1908 // hidden first parameter, in which case we need the more
1909 // complicated approach. This is true even though we are going to
1910 // ignore the return value.
1911 const Typed_identifier_list
* results
= fntype
->results();
1913 && (results
->size() > 1
1914 || (results
->size() == 1
1915 && !results
->begin()->type()->is_basic_type()
1916 && results
->begin()->type()->points_to() == NULL
)))
1919 // If this calls something that is not a simple function, then we
1921 Expression
* fn
= this->call_
->call_expression()->fn();
1922 if (fn
->func_expression() == NULL
)
1925 // If the function uses a closure, then we need a thunk. FIXME: We
1926 // could accept a zero argument function with a closure.
1927 if (fn
->func_expression()->closure() != NULL
)
1933 // Traverse a thunk statement.
1936 Thunk_statement::do_traverse(Traverse
* traverse
)
1938 return this->traverse_expression(traverse
, &this->call_
);
1941 // We implement traverse_assignment for a thunk statement because it
1942 // effectively copies the function call.
1945 Thunk_statement::do_traverse_assignments(Traverse_assignments
* tassign
)
1947 Expression
* fn
= this->call_
->call_expression()->fn();
1948 Expression
* fn2
= fn
;
1949 tassign
->value(&fn2
, true, false);
1953 // Determine types in a thunk statement.
1956 Thunk_statement::do_determine_types()
1958 this->call_
->determine_type_no_context();
1960 // Now that we know the types of the call, build the struct used to
1962 Call_expression
* ce
= this->call_
->call_expression();
1965 Function_type
* fntype
= ce
->get_function_type();
1966 if (fntype
!= NULL
&& !this->is_simple(fntype
))
1967 this->struct_type_
= this->build_struct(fntype
);
1970 // Check types in a thunk statement.
1973 Thunk_statement::do_check_types(Gogo
*)
1975 if (!this->call_
->discarding_value())
1977 Call_expression
* ce
= this->call_
->call_expression();
1980 if (!this->call_
->is_error_expression())
1981 this->report_error("expected call expression");
1986 // The Traverse class used to find and simplify thunk statements.
1988 class Simplify_thunk_traverse
: public Traverse
1991 Simplify_thunk_traverse(Gogo
* gogo
)
1992 : Traverse(traverse_functions
| traverse_blocks
),
1993 gogo_(gogo
), function_(NULL
)
1997 function(Named_object
*);
2005 // The function we are traversing.
2006 Named_object
* function_
;
2009 // Keep track of the current function while looking for thunks.
2012 Simplify_thunk_traverse::function(Named_object
* no
)
2014 go_assert(this->function_
== NULL
);
2015 this->function_
= no
;
2016 int t
= no
->func_value()->traverse(this);
2017 this->function_
= NULL
;
2018 if (t
== TRAVERSE_EXIT
)
2020 return TRAVERSE_SKIP_COMPONENTS
;
2023 // Look for thunks in a block.
2026 Simplify_thunk_traverse::block(Block
* b
)
2028 // The parser ensures that thunk statements always appear at the end
2030 if (b
->statements()->size() < 1)
2031 return TRAVERSE_CONTINUE
;
2032 Thunk_statement
* stat
= b
->statements()->back()->thunk_statement();
2034 return TRAVERSE_CONTINUE
;
2035 if (stat
->simplify_statement(this->gogo_
, this->function_
, b
))
2036 return TRAVERSE_SKIP_COMPONENTS
;
2037 return TRAVERSE_CONTINUE
;
2040 // Simplify all thunk statements.
2043 Gogo::simplify_thunk_statements()
2045 Simplify_thunk_traverse
thunk_traverse(this);
2046 this->traverse(&thunk_traverse
);
2049 // Return true if the thunk function is a constant, which means that
2050 // it does not need to be passed to the thunk routine.
2053 Thunk_statement::is_constant_function() const
2055 Call_expression
* ce
= this->call_
->call_expression();
2056 Function_type
* fntype
= ce
->get_function_type();
2059 go_assert(saw_errors());
2062 if (fntype
->is_builtin())
2064 Expression
* fn
= ce
->fn();
2065 if (fn
->func_expression() != NULL
)
2066 return fn
->func_expression()->closure() == NULL
;
2067 if (fn
->interface_field_reference_expression() != NULL
)
2072 // Simplify complex thunk statements into simple ones. A complicated
2073 // thunk statement is one which takes anything other than zero
2074 // parameters or a single pointer parameter. We rewrite it into code
2075 // which allocates a struct, stores the parameter values into the
2076 // struct, and does a simple go or defer statement which passes the
2077 // struct to a thunk. The thunk does the real call.
2080 Thunk_statement::simplify_statement(Gogo
* gogo
, Named_object
* function
,
2083 if (this->classification() == STATEMENT_ERROR
)
2085 if (this->call_
->is_error_expression())
2088 if (this->classification() == STATEMENT_DEFER
)
2090 // Make sure that the defer stack exists for the function. We
2091 // will use when converting this statement to the backend
2092 // representation, but we want it to exist when we start
2093 // converting the function.
2094 function
->func_value()->defer_stack(this->location());
2097 Call_expression
* ce
= this->call_
->call_expression();
2098 Function_type
* fntype
= ce
->get_function_type();
2101 go_assert(saw_errors());
2102 this->set_is_error();
2105 if (this->is_simple(fntype
))
2108 Expression
* fn
= ce
->fn();
2109 Interface_field_reference_expression
* interface_method
=
2110 fn
->interface_field_reference_expression();
2112 Location location
= this->location();
2114 bool is_constant_function
= this->is_constant_function();
2115 Temporary_statement
* fn_temp
= NULL
;
2116 if (!is_constant_function
)
2118 fn_temp
= Statement::make_temporary(NULL
, fn
, location
);
2119 block
->insert_statement_before(block
->statements()->size() - 1, fn_temp
);
2120 fn
= Expression::make_temporary_reference(fn_temp
, location
);
2123 std::string thunk_name
= Gogo::thunk_name();
2126 this->build_thunk(gogo
, thunk_name
);
2128 // Generate code to call the thunk.
2130 // Get the values to store into the struct which is the single
2131 // argument to the thunk.
2133 Expression_list
* vals
= new Expression_list();
2134 if (!is_constant_function
)
2135 vals
->push_back(fn
);
2137 if (interface_method
!= NULL
)
2138 vals
->push_back(interface_method
->expr());
2140 if (ce
->args() != NULL
)
2142 for (Expression_list::const_iterator p
= ce
->args()->begin();
2143 p
!= ce
->args()->end();
2146 if ((*p
)->is_constant())
2148 vals
->push_back(*p
);
2152 // Build the struct.
2153 Expression
* constructor
=
2154 Expression::make_struct_composite_literal(this->struct_type_
, vals
,
2157 // Allocate the initialized struct on the heap.
2158 constructor
= Expression::make_heap_expression(constructor
, location
);
2160 // Throw an error if the function is nil. This is so that for `go
2161 // nil` we get a backtrace from the go statement, rather than a
2162 // useless backtrace from the brand new goroutine.
2163 Expression
* param
= constructor
;
2164 if (!is_constant_function
)
2166 fn
= Expression::make_temporary_reference(fn_temp
, location
);
2167 Expression
* nil
= Expression::make_nil(location
);
2168 Expression
* isnil
= Expression::make_binary(OPERATOR_EQEQ
, fn
, nil
,
2170 Expression
* crash
= gogo
->runtime_error(RUNTIME_ERROR_GO_NIL
, location
);
2171 crash
= Expression::make_conditional(isnil
, crash
,
2172 Expression::make_nil(location
),
2174 param
= Expression::make_compound(crash
, constructor
, location
);
2177 // Look up the thunk.
2178 Named_object
* named_thunk
= gogo
->lookup(thunk_name
, NULL
);
2179 go_assert(named_thunk
!= NULL
&& named_thunk
->is_function());
2182 Expression
* func
= Expression::make_func_reference(named_thunk
, NULL
,
2184 Expression_list
* params
= new Expression_list();
2185 params
->push_back(param
);
2186 Call_expression
* call
= Expression::make_call(func
, params
, false, location
);
2188 // Build the simple go or defer statement.
2190 if (this->classification() == STATEMENT_GO
)
2191 s
= Statement::make_go_statement(call
, location
);
2192 else if (this->classification() == STATEMENT_DEFER
)
2193 s
= Statement::make_defer_statement(call
, location
);
2197 // The current block should end with the go statement.
2198 go_assert(block
->statements()->size() >= 1);
2199 go_assert(block
->statements()->back() == this);
2200 block
->replace_statement(block
->statements()->size() - 1, s
);
2202 // We already ran the determine_types pass, so we need to run it now
2203 // for the new statement.
2204 s
->determine_types();
2207 gogo
->check_types_in_block(block
);
2209 // Return true to tell the block not to keep looking at statements.
2213 // Set the name to use for thunk parameter N.
2216 Thunk_statement::thunk_field_param(int n
, char* buf
, size_t buflen
)
2218 snprintf(buf
, buflen
, "a%d", n
);
2221 // Build a new struct type to hold the parameters for a complicated
2222 // thunk statement. FNTYPE is the type of the function call.
2225 Thunk_statement::build_struct(Function_type
* fntype
)
2227 Location location
= this->location();
2229 Struct_field_list
* fields
= new Struct_field_list();
2231 Call_expression
* ce
= this->call_
->call_expression();
2232 Expression
* fn
= ce
->fn();
2234 if (!this->is_constant_function())
2236 // The function to call.
2237 fields
->push_back(Struct_field(Typed_identifier("fn", fntype
,
2241 // If this thunk statement calls a method on an interface, we pass
2242 // the interface object to the thunk.
2243 Interface_field_reference_expression
* interface_method
=
2244 fn
->interface_field_reference_expression();
2245 if (interface_method
!= NULL
)
2247 Typed_identifier
tid("object", interface_method
->expr()->type(),
2249 fields
->push_back(Struct_field(tid
));
2252 // The predeclared recover function has no argument. However, we
2253 // add an argument when building recover thunks. Handle that here.
2254 if (ce
->is_recover_call())
2256 fields
->push_back(Struct_field(Typed_identifier("can_recover",
2257 Type::lookup_bool_type(),
2261 const Expression_list
* args
= ce
->args();
2265 for (Expression_list::const_iterator p
= args
->begin();
2269 if ((*p
)->is_constant())
2273 this->thunk_field_param(i
, buf
, sizeof buf
);
2274 fields
->push_back(Struct_field(Typed_identifier(buf
, (*p
)->type(),
2279 Struct_type
*st
= Type::make_struct_type(fields
, location
);
2280 st
->set_is_struct_incomparable();
2284 // Build the thunk we are going to call. This is a brand new, albeit
2285 // artificial, function.
2288 Thunk_statement::build_thunk(Gogo
* gogo
, const std::string
& thunk_name
)
2290 Location location
= this->location();
2292 Call_expression
* ce
= this->call_
->call_expression();
2294 bool may_call_recover
= false;
2295 if (this->classification() == STATEMENT_DEFER
)
2297 Func_expression
* fn
= ce
->fn()->func_expression();
2299 may_call_recover
= true;
2302 const Named_object
* no
= fn
->named_object();
2303 if (!no
->is_function())
2304 may_call_recover
= true;
2306 may_call_recover
= no
->func_value()->calls_recover();
2310 // Build the type of the thunk. The thunk takes a single parameter,
2311 // which is a pointer to the special structure we build.
2312 const char* const parameter_name
= "__go_thunk_parameter";
2313 Typed_identifier_list
* thunk_parameters
= new Typed_identifier_list();
2314 Type
* pointer_to_struct_type
= Type::make_pointer_type(this->struct_type_
);
2315 thunk_parameters
->push_back(Typed_identifier(parameter_name
,
2316 pointer_to_struct_type
,
2319 Typed_identifier_list
* thunk_results
= NULL
;
2320 if (may_call_recover
)
2322 // When deferring a function which may call recover, add a
2323 // return value, to disable tail call optimizations which will
2324 // break the way we check whether recover is permitted.
2325 thunk_results
= new Typed_identifier_list();
2326 thunk_results
->push_back(Typed_identifier("", Type::lookup_bool_type(),
2330 Function_type
* thunk_type
= Type::make_function_type(NULL
, thunk_parameters
,
2334 // Start building the thunk.
2335 Named_object
* function
= gogo
->start_function(thunk_name
, thunk_type
, true,
2338 gogo
->start_block(location
);
2340 // For a defer statement, start with a call to
2341 // __go_set_defer_retaddr. */
2342 Label
* retaddr_label
= NULL
;
2343 if (may_call_recover
)
2345 retaddr_label
= gogo
->add_label_reference("retaddr", location
, false);
2346 Expression
* arg
= Expression::make_label_addr(retaddr_label
, location
);
2347 Expression
* call
= Runtime::make_call(Runtime::SETDEFERRETADDR
,
2350 // This is a hack to prevent the middle-end from deleting the
2352 gogo
->start_block(location
);
2353 gogo
->add_statement(Statement::make_goto_statement(retaddr_label
,
2355 Block
* then_block
= gogo
->finish_block(location
);
2356 then_block
->determine_types();
2358 Statement
* s
= Statement::make_if_statement(call
, then_block
, NULL
,
2360 s
->determine_types();
2361 gogo
->add_statement(s
);
2363 function
->func_value()->set_calls_defer_retaddr();
2366 // Get a reference to the parameter.
2367 Named_object
* named_parameter
= gogo
->lookup(parameter_name
, NULL
);
2368 go_assert(named_parameter
!= NULL
&& named_parameter
->is_variable());
2370 // Build the call. Note that the field names are the same as the
2371 // ones used in build_struct.
2372 Expression
* thunk_parameter
= Expression::make_var_reference(named_parameter
,
2375 Expression::make_dereference(thunk_parameter
,
2376 Expression::NIL_CHECK_NOT_NEEDED
,
2379 Interface_field_reference_expression
* interface_method
=
2380 ce
->fn()->interface_field_reference_expression();
2382 Expression
* func_to_call
;
2383 unsigned int next_index
;
2384 if (this->is_constant_function())
2386 func_to_call
= ce
->fn();
2391 func_to_call
= Expression::make_field_reference(thunk_parameter
,
2396 if (interface_method
!= NULL
)
2398 // The main program passes the interface object.
2399 go_assert(next_index
== 0);
2400 Expression
* r
= Expression::make_field_reference(thunk_parameter
, 0,
2402 const std::string
& name(interface_method
->name());
2403 func_to_call
= Expression::make_interface_field_reference(r
, name
,
2408 Expression_list
* call_params
= new Expression_list();
2409 const Struct_field_list
* fields
= this->struct_type_
->fields();
2410 Struct_field_list::const_iterator p
= fields
->begin();
2411 for (unsigned int i
= 0; i
< next_index
; ++i
)
2413 bool is_recover_call
= ce
->is_recover_call();
2414 Expression
* recover_arg
= NULL
;
2416 const Expression_list
* args
= ce
->args();
2419 for (Expression_list::const_iterator arg
= args
->begin();
2424 if ((*arg
)->is_constant())
2428 Expression
* thunk_param
=
2429 Expression::make_var_reference(named_parameter
, location
);
2431 Expression::make_dereference(thunk_param
,
2432 Expression::NIL_CHECK_NOT_NEEDED
,
2434 param
= Expression::make_field_reference(thunk_param
,
2440 if (!is_recover_call
)
2441 call_params
->push_back(param
);
2444 go_assert(call_params
->empty());
2445 recover_arg
= param
;
2450 if (call_params
->empty())
2456 Call_expression
* call
= Expression::make_call(func_to_call
, call_params
,
2459 // This call expression was already lowered before entering the
2460 // thunk statement. Don't try to lower varargs again, as that will
2461 // cause confusion for, e.g., method calls which already have a
2462 // receiver parameter.
2463 call
->set_varargs_are_lowered();
2465 Statement
* call_statement
= Statement::make_statement(call
, true);
2467 gogo
->add_statement(call_statement
);
2469 // If this is a defer statement, the label comes immediately after
2471 if (may_call_recover
)
2473 gogo
->add_label_definition("retaddr", location
);
2475 Expression_list
* vals
= new Expression_list();
2476 vals
->push_back(Expression::make_boolean(false, location
));
2477 gogo
->add_statement(Statement::make_return_statement(vals
, location
));
2480 Block
* b
= gogo
->finish_block(location
);
2482 gogo
->add_block(b
, location
);
2484 gogo
->lower_block(function
, b
);
2486 // We already ran the determine_types pass, so we need to run it
2487 // just for the call statement now. The other types are known.
2488 call_statement
->determine_types();
2490 gogo
->flatten_block(function
, b
);
2492 if (may_call_recover
2493 || recover_arg
!= NULL
2494 || this->classification() == STATEMENT_GO
)
2496 // Dig up the call expression, which may have been changed
2498 go_assert(call_statement
->classification() == STATEMENT_EXPRESSION
);
2499 Expression_statement
* es
=
2500 static_cast<Expression_statement
*>(call_statement
);
2501 Call_expression
* ce
= es
->expr()->call_expression();
2503 go_assert(saw_errors());
2506 if (may_call_recover
)
2507 ce
->set_is_deferred();
2508 if (this->classification() == STATEMENT_GO
)
2509 ce
->set_is_concurrent();
2510 if (recover_arg
!= NULL
)
2511 ce
->set_recover_arg(recover_arg
);
2515 // That is all the thunk has to do.
2516 gogo
->finish_function(location
);
2519 // Get the function and argument expressions.
2522 Thunk_statement::get_fn_and_arg(Expression
** pfn
, Expression
** parg
)
2524 if (this->call_
->is_error_expression())
2527 Call_expression
* ce
= this->call_
->call_expression();
2529 Expression
* fn
= ce
->fn();
2530 Func_expression
* fe
= fn
->func_expression();
2531 go_assert(fe
!= NULL
);
2532 *pfn
= Expression::make_func_code_reference(fe
->named_object(),
2535 const Expression_list
* args
= ce
->args();
2536 if (args
== NULL
|| args
->empty())
2537 *parg
= Expression::make_nil(this->location());
2540 go_assert(args
->size() == 1);
2541 *parg
= args
->front();
2547 // Class Go_statement.
2550 Go_statement::do_get_backend(Translate_context
* context
)
2554 if (!this->get_fn_and_arg(&fn
, &arg
))
2555 return context
->backend()->error_statement();
2557 Expression
* call
= Runtime::make_call(Runtime::GO
, this->location(), 2,
2559 Bexpression
* bcall
= call
->get_backend(context
);
2560 Bfunction
* bfunction
= context
->function()->func_value()->get_decl();
2561 return context
->backend()->expression_statement(bfunction
, bcall
);
2564 // Dump the AST representation for go statement.
2567 Go_statement::do_dump_statement(Ast_dump_context
* ast_dump_context
) const
2569 ast_dump_context
->print_indent();
2570 ast_dump_context
->ostream() << "go ";
2571 ast_dump_context
->dump_expression(this->call());
2572 ast_dump_context
->ostream() << dsuffix(location()) << std::endl
;
2575 // Make a go statement.
2578 Statement::make_go_statement(Call_expression
* call
, Location location
)
2580 return new Go_statement(call
, location
);
2583 // Class Defer_statement.
2586 Defer_statement::do_get_backend(Translate_context
* context
)
2590 if (!this->get_fn_and_arg(&fn
, &arg
))
2591 return context
->backend()->error_statement();
2593 Location loc
= this->location();
2594 Expression
* ds
= context
->function()->func_value()->defer_stack(loc
);
2596 Expression
* call
= Runtime::make_call(Runtime::DEFERPROC
, loc
, 3,
2598 Bexpression
* bcall
= call
->get_backend(context
);
2599 Bfunction
* bfunction
= context
->function()->func_value()->get_decl();
2600 return context
->backend()->expression_statement(bfunction
, bcall
);
2603 // Dump the AST representation for defer statement.
2606 Defer_statement::do_dump_statement(Ast_dump_context
* ast_dump_context
) const
2608 ast_dump_context
->print_indent();
2609 ast_dump_context
->ostream() << "defer ";
2610 ast_dump_context
->dump_expression(this->call());
2611 ast_dump_context
->ostream() << dsuffix(location()) << std::endl
;
2614 // Make a defer statement.
2617 Statement::make_defer_statement(Call_expression
* call
,
2620 return new Defer_statement(call
, location
);
2623 // Class Return_statement.
2625 // Traverse assignments. We treat each return value as a top level
2626 // RHS in an expression.
2629 Return_statement::do_traverse_assignments(Traverse_assignments
* tassign
)
2631 Expression_list
* vals
= this->vals_
;
2634 for (Expression_list::iterator p
= vals
->begin();
2637 tassign
->value(&*p
, true, true);
2642 // Lower a return statement. If we are returning a function call
2643 // which returns multiple values which match the current function,
2644 // split up the call's results. If the return statement lists
2645 // explicit values, implement this statement by assigning the values
2646 // to the result variables and change this statement to a naked
2647 // return. This lets panic/recover work correctly.
2650 Return_statement::do_lower(Gogo
*, Named_object
* function
, Block
* enclosing
,
2651 Statement_inserter
*)
2653 if (this->is_lowered_
)
2656 Expression_list
* vals
= this->vals_
;
2658 this->is_lowered_
= true;
2660 Location loc
= this->location();
2662 size_t vals_count
= vals
== NULL
? 0 : vals
->size();
2663 Function::Results
* results
= function
->func_value()->result_variables();
2664 size_t results_count
= results
== NULL
? 0 : results
->size();
2666 if (vals_count
== 0)
2668 if (results_count
> 0 && !function
->func_value()->results_are_named())
2670 this->report_error(_("not enough arguments to return"));
2676 if (results_count
== 0)
2678 this->report_error(_("return with value in function "
2679 "with no return type"));
2683 // If the current function has multiple return values, and we are
2684 // returning a single call expression, split up the call expression.
2685 if (results_count
> 1
2686 && vals
->size() == 1
2687 && vals
->front()->call_expression() != NULL
)
2689 Call_expression
* call
= vals
->front()->call_expression();
2690 call
->set_expected_result_count(results_count
);
2692 vals
= new Expression_list
;
2693 for (size_t i
= 0; i
< results_count
; ++i
)
2694 vals
->push_back(Expression::make_call_result(call
, i
));
2695 vals_count
= results_count
;
2698 if (vals_count
< results_count
)
2700 this->report_error(_("not enough arguments to return"));
2704 if (vals_count
> results_count
)
2706 this->report_error(_("too many values in return statement"));
2710 Block
* b
= new Block(enclosing
, loc
);
2712 Expression_list
* lhs
= new Expression_list();
2713 Expression_list
* rhs
= new Expression_list();
2715 Expression_list::const_iterator pe
= vals
->begin();
2717 for (Function::Results::const_iterator pr
= results
->begin();
2718 pr
!= results
->end();
2721 Named_object
* rv
= *pr
;
2722 Expression
* e
= *pe
;
2724 // Check types now so that we give a good error message. The
2725 // result type is known. We determine the expression type
2728 Type
*rvtype
= rv
->result_var_value()->type();
2729 Type_context
type_context(rvtype
, false);
2730 e
->determine_type(&type_context
);
2733 if (Type::are_assignable(rvtype
, e
->type(), &reason
))
2735 Expression
* ve
= Expression::make_var_reference(rv
, e
->location());
2742 go_error_at(e
->location(),
2743 "incompatible type for return value %d", i
);
2745 go_error_at(e
->location(),
2746 "incompatible type for return value %d (%s)",
2750 go_assert(lhs
->size() == rhs
->size());
2754 else if (lhs
->size() == 1)
2756 b
->add_statement(Statement::make_assignment(lhs
->front(), rhs
->front(),
2762 b
->add_statement(Statement::make_tuple_assignment(lhs
, rhs
, loc
));
2764 b
->add_statement(this);
2768 return Statement::make_block_statement(b
, loc
);
2771 // Convert a return statement to the backend representation.
2774 Return_statement::do_get_backend(Translate_context
* context
)
2776 Location loc
= this->location();
2778 Function
* function
= context
->function()->func_value();
2779 Function::Results
* results
= function
->result_variables();
2780 std::vector
<Bexpression
*> retvals
;
2781 if (results
!= NULL
&& !results
->empty())
2783 retvals
.reserve(results
->size());
2784 for (Function::Results::const_iterator p
= results
->begin();
2785 p
!= results
->end();
2788 Expression
* vr
= Expression::make_var_reference(*p
, loc
);
2789 retvals
.push_back(vr
->get_backend(context
));
2793 return context
->backend()->return_statement(function
->get_decl(),
2797 // Dump the AST representation for a return statement.
2800 Return_statement::do_dump_statement(Ast_dump_context
* ast_dump_context
) const
2802 ast_dump_context
->print_indent();
2803 ast_dump_context
->ostream() << "return " ;
2804 ast_dump_context
->dump_expression_list(this->vals_
);
2805 ast_dump_context
->ostream() << dsuffix(location()) << std::endl
;
2808 // Make a return statement.
2811 Statement::make_return_statement(Expression_list
* vals
,
2814 return new Return_statement(vals
, location
);
2817 // Make a statement that returns the result of a call expression.
2820 Statement::make_return_from_call(Call_expression
* call
, Location location
)
2822 size_t rc
= call
->result_count();
2824 return Statement::make_statement(call
, true);
2827 Expression_list
* vals
= new Expression_list();
2829 vals
->push_back(call
);
2832 for (size_t i
= 0; i
< rc
; ++i
)
2833 vals
->push_back(Expression::make_call_result(call
, i
));
2835 return Statement::make_return_statement(vals
, location
);
2839 // A break or continue statement.
2841 class Bc_statement
: public Statement
2844 Bc_statement(bool is_break
, Unnamed_label
* label
, Location location
)
2845 : Statement(STATEMENT_BREAK_OR_CONTINUE
, location
),
2846 label_(label
), is_break_(is_break
)
2851 { return this->is_break_
; }
2855 do_traverse(Traverse
*)
2856 { return TRAVERSE_CONTINUE
; }
2859 do_may_fall_through() const
2863 do_get_backend(Translate_context
* context
)
2864 { return this->label_
->get_goto(context
, this->location()); }
2867 do_dump_statement(Ast_dump_context
*) const;
2870 // The label that this branches to.
2871 Unnamed_label
* label_
;
2872 // True if this is "break", false if it is "continue".
2876 // Dump the AST representation for a break/continue statement
2879 Bc_statement::do_dump_statement(Ast_dump_context
* ast_dump_context
) const
2881 ast_dump_context
->print_indent();
2882 ast_dump_context
->ostream() << (this->is_break_
? "break" : "continue");
2883 if (this->label_
!= NULL
)
2885 ast_dump_context
->ostream() << " ";
2886 ast_dump_context
->dump_label_name(this->label_
);
2888 ast_dump_context
->ostream() << dsuffix(location()) << std::endl
;
2891 // Make a break statement.
2894 Statement::make_break_statement(Unnamed_label
* label
, Location location
)
2896 return new Bc_statement(true, label
, location
);
2899 // Make a continue statement.
2902 Statement::make_continue_statement(Unnamed_label
* label
,
2905 return new Bc_statement(false, label
, location
);
2908 // Class Goto_statement.
2911 Goto_statement::do_traverse(Traverse
*)
2913 return TRAVERSE_CONTINUE
;
2916 // Check types for a label. There aren't any types per se, but we use
2917 // this to give an error if the label was never defined.
2920 Goto_statement::do_check_types(Gogo
*)
2922 if (!this->label_
->is_defined())
2924 go_error_at(this->location(), "reference to undefined label %qs",
2925 Gogo::message_name(this->label_
->name()).c_str());
2926 this->set_is_error();
2930 // Convert the goto statement to the backend representation.
2933 Goto_statement::do_get_backend(Translate_context
* context
)
2935 Blabel
* blabel
= this->label_
->get_backend_label(context
);
2936 return context
->backend()->goto_statement(blabel
, this->location());
2939 // Dump the AST representation for a goto statement.
2942 Goto_statement::do_dump_statement(Ast_dump_context
* ast_dump_context
) const
2944 ast_dump_context
->print_indent();
2945 ast_dump_context
->ostream() << "goto " << this->label_
->name() << dsuffix(location()) << std::endl
;
2948 // Make a goto statement.
2951 Statement::make_goto_statement(Label
* label
, Location location
)
2953 return new Goto_statement(label
, location
);
2956 // Class Goto_unnamed_statement.
2959 Goto_unnamed_statement::do_traverse(Traverse
*)
2961 return TRAVERSE_CONTINUE
;
2964 // Convert the goto unnamed statement to the backend representation.
2967 Goto_unnamed_statement::do_get_backend(Translate_context
* context
)
2969 return this->label_
->get_goto(context
, this->location());
2972 // Dump the AST representation for an unnamed goto statement
2975 Goto_unnamed_statement::do_dump_statement(
2976 Ast_dump_context
* ast_dump_context
) const
2978 ast_dump_context
->print_indent();
2979 ast_dump_context
->ostream() << "goto ";
2980 ast_dump_context
->dump_label_name(this->label_
);
2981 ast_dump_context
->ostream() << dsuffix(location()) << std::endl
;
2984 // Make a goto statement to an unnamed label.
2987 Statement::make_goto_unnamed_statement(Unnamed_label
* label
,
2990 return new Goto_unnamed_statement(label
, location
);
2993 // Class Label_statement.
2998 Label_statement::do_traverse(Traverse
*)
3000 return TRAVERSE_CONTINUE
;
3003 // Return the backend representation of the statement defining this
3007 Label_statement::do_get_backend(Translate_context
* context
)
3009 if (this->label_
->is_dummy_label())
3011 Bexpression
* bce
= context
->backend()->boolean_constant_expression(false);
3012 Bfunction
* bfunction
= context
->function()->func_value()->get_decl();
3013 return context
->backend()->expression_statement(bfunction
, bce
);
3015 Blabel
* blabel
= this->label_
->get_backend_label(context
);
3016 return context
->backend()->label_definition_statement(blabel
);
3019 // Dump the AST for a label definition statement.
3022 Label_statement::do_dump_statement(Ast_dump_context
* ast_dump_context
) const
3024 ast_dump_context
->print_indent();
3025 ast_dump_context
->ostream() << this->label_
->name() << ":" << dsuffix(location()) << std::endl
;
3028 // Make a label statement.
3031 Statement::make_label_statement(Label
* label
, Location location
)
3033 return new Label_statement(label
, location
);
3036 // Class Unnamed_label_statement.
3038 Unnamed_label_statement::Unnamed_label_statement(Unnamed_label
* label
)
3039 : Statement(STATEMENT_UNNAMED_LABEL
, label
->location()),
3044 Unnamed_label_statement::do_traverse(Traverse
*)
3046 return TRAVERSE_CONTINUE
;
3049 // Get the backend definition for this unnamed label statement.
3052 Unnamed_label_statement::do_get_backend(Translate_context
* context
)
3054 return this->label_
->get_definition(context
);
3057 // Dump the AST representation for an unnamed label definition statement.
3060 Unnamed_label_statement::do_dump_statement(Ast_dump_context
* ast_dump_context
)
3063 ast_dump_context
->print_indent();
3064 ast_dump_context
->dump_label_name(this->label_
);
3065 ast_dump_context
->ostream() << ":" << dsuffix(location()) << std::endl
;
3068 // Make an unnamed label statement.
3071 Statement::make_unnamed_label_statement(Unnamed_label
* label
)
3073 return new Unnamed_label_statement(label
);
3076 // Class If_statement.
3081 If_statement::do_traverse(Traverse
* traverse
)
3083 if (this->traverse_expression(traverse
, &this->cond_
) == TRAVERSE_EXIT
3084 || this->then_block_
->traverse(traverse
) == TRAVERSE_EXIT
)
3085 return TRAVERSE_EXIT
;
3086 if (this->else_block_
!= NULL
)
3088 if (this->else_block_
->traverse(traverse
) == TRAVERSE_EXIT
)
3089 return TRAVERSE_EXIT
;
3091 return TRAVERSE_CONTINUE
;
3095 If_statement::do_determine_types()
3097 Type_context
context(Type::lookup_bool_type(), false);
3098 this->cond_
->determine_type(&context
);
3099 this->then_block_
->determine_types();
3100 if (this->else_block_
!= NULL
)
3101 this->else_block_
->determine_types();
3107 If_statement::do_check_types(Gogo
*)
3109 Type
* type
= this->cond_
->type();
3110 if (type
->is_error())
3111 this->set_is_error();
3112 else if (!type
->is_boolean_type())
3113 this->report_error(_("expected boolean expression"));
3116 // Whether the overall statement may fall through.
3119 If_statement::do_may_fall_through() const
3121 return (this->else_block_
== NULL
3122 || this->then_block_
->may_fall_through()
3123 || this->else_block_
->may_fall_through());
3126 // Get the backend representation.
3129 If_statement::do_get_backend(Translate_context
* context
)
3131 go_assert(this->cond_
->type()->is_boolean_type()
3132 || this->cond_
->type()->is_error());
3133 Bexpression
* cond
= this->cond_
->get_backend(context
);
3134 Bblock
* then_block
= this->then_block_
->get_backend(context
);
3135 Bblock
* else_block
= (this->else_block_
== NULL
3137 : this->else_block_
->get_backend(context
));
3138 Bfunction
* bfunction
= context
->function()->func_value()->get_decl();
3139 return context
->backend()->if_statement(bfunction
,
3140 cond
, then_block
, else_block
,
3144 // Dump the AST representation for an if statement
3147 If_statement::do_dump_statement(Ast_dump_context
* ast_dump_context
) const
3149 ast_dump_context
->print_indent();
3150 ast_dump_context
->ostream() << "if ";
3151 ast_dump_context
->dump_expression(this->cond_
);
3152 ast_dump_context
->ostream() << dsuffix(location()) << std::endl
;
3153 if (ast_dump_context
->dump_subblocks())
3155 ast_dump_context
->dump_block(this->then_block_
);
3156 if (this->else_block_
!= NULL
)
3158 ast_dump_context
->print_indent();
3159 ast_dump_context
->ostream() << "else" << std::endl
;
3160 ast_dump_context
->dump_block(this->else_block_
);
3165 // Make an if statement.
3168 Statement::make_if_statement(Expression
* cond
, Block
* then_block
,
3169 Block
* else_block
, Location location
)
3171 return new If_statement(cond
, then_block
, else_block
, location
);
3174 // Class Case_clauses::Hash_integer_value.
3176 class Case_clauses::Hash_integer_value
3180 operator()(Expression
*) const;
3184 Case_clauses::Hash_integer_value::operator()(Expression
* pe
) const
3186 Numeric_constant nc
;
3188 if (!pe
->numeric_constant_value(&nc
) || !nc
.to_int(&ival
))
3190 size_t ret
= mpz_get_ui(ival
);
3195 // Class Case_clauses::Eq_integer_value.
3197 class Case_clauses::Eq_integer_value
3201 operator()(Expression
*, Expression
*) const;
3205 Case_clauses::Eq_integer_value::operator()(Expression
* a
, Expression
* b
) const
3207 Numeric_constant anc
;
3209 Numeric_constant bnc
;
3211 if (!a
->numeric_constant_value(&anc
)
3212 || !anc
.to_int(&aval
)
3213 || !b
->numeric_constant_value(&bnc
)
3214 || !bnc
.to_int(&bval
))
3216 bool ret
= mpz_cmp(aval
, bval
) == 0;
3222 // Class Case_clauses::Case_clause.
3227 Case_clauses::Case_clause::traverse(Traverse
* traverse
)
3229 if (this->cases_
!= NULL
3230 && (traverse
->traverse_mask()
3231 & (Traverse::traverse_types
| Traverse::traverse_expressions
)) != 0)
3233 if (this->cases_
->traverse(traverse
) == TRAVERSE_EXIT
)
3234 return TRAVERSE_EXIT
;
3236 if (this->statements_
!= NULL
)
3238 if (this->statements_
->traverse(traverse
) == TRAVERSE_EXIT
)
3239 return TRAVERSE_EXIT
;
3241 return TRAVERSE_CONTINUE
;
3244 // Check whether all the case expressions are integer constants.
3247 Case_clauses::Case_clause::is_constant() const
3249 if (this->cases_
!= NULL
)
3251 for (Expression_list::const_iterator p
= this->cases_
->begin();
3252 p
!= this->cases_
->end();
3254 if (!(*p
)->is_constant() || (*p
)->type()->integer_type() == NULL
)
3260 // Lower a case clause for a nonconstant switch. VAL_TEMP is the
3261 // value we are switching on; it may be NULL. If START_LABEL is not
3262 // NULL, it goes at the start of the statements, after the condition
3263 // test. We branch to FINISH_LABEL at the end of the statements.
3266 Case_clauses::Case_clause::lower(Block
* b
, Temporary_statement
* val_temp
,
3267 Unnamed_label
* start_label
,
3268 Unnamed_label
* finish_label
) const
3270 Location loc
= this->location_
;
3271 Unnamed_label
* next_case_label
;
3272 if (this->cases_
== NULL
|| this->cases_
->empty())
3274 go_assert(this->is_default_
);
3275 next_case_label
= NULL
;
3279 Expression
* cond
= NULL
;
3281 for (Expression_list::const_iterator p
= this->cases_
->begin();
3282 p
!= this->cases_
->end();
3285 Expression
* ref
= Expression::make_temporary_reference(val_temp
,
3287 Expression
* this_cond
= Expression::make_binary(OPERATOR_EQEQ
, ref
,
3292 cond
= Expression::make_binary(OPERATOR_OROR
, cond
, this_cond
, loc
);
3295 Block
* then_block
= new Block(b
, loc
);
3296 next_case_label
= new Unnamed_label(Linemap::unknown_location());
3297 Statement
* s
= Statement::make_goto_unnamed_statement(next_case_label
,
3299 then_block
->add_statement(s
);
3301 // if !COND { goto NEXT_CASE_LABEL }
3302 cond
= Expression::make_unary(OPERATOR_NOT
, cond
, loc
);
3303 s
= Statement::make_if_statement(cond
, then_block
, NULL
, loc
);
3304 b
->add_statement(s
);
3307 if (start_label
!= NULL
)
3308 b
->add_statement(Statement::make_unnamed_label_statement(start_label
));
3310 if (this->statements_
!= NULL
)
3311 b
->add_statement(Statement::make_block_statement(this->statements_
, loc
));
3313 Statement
* s
= Statement::make_goto_unnamed_statement(finish_label
, loc
);
3314 b
->add_statement(s
);
3316 if (next_case_label
!= NULL
)
3317 b
->add_statement(Statement::make_unnamed_label_statement(next_case_label
));
3323 Case_clauses::Case_clause::determine_types(Type
* type
)
3325 if (this->cases_
!= NULL
)
3327 Type_context
case_context(type
, false);
3328 for (Expression_list::iterator p
= this->cases_
->begin();
3329 p
!= this->cases_
->end();
3331 (*p
)->determine_type(&case_context
);
3333 if (this->statements_
!= NULL
)
3334 this->statements_
->determine_types();
3337 // Check types. Returns false if there was an error.
3340 Case_clauses::Case_clause::check_types(Type
* type
)
3342 if (this->cases_
!= NULL
)
3344 for (Expression_list::iterator p
= this->cases_
->begin();
3345 p
!= this->cases_
->end();
3348 if (!Type::are_assignable(type
, (*p
)->type(), NULL
)
3349 && !Type::are_assignable((*p
)->type(), type
, NULL
))
3351 go_error_at((*p
)->location(),
3352 "type mismatch between switch value and case clause");
3360 // Return true if this clause may fall through to the following
3361 // statements. Note that this is not the same as whether the case
3362 // uses the "fallthrough" keyword.
3365 Case_clauses::Case_clause::may_fall_through() const
3367 if (this->statements_
== NULL
)
3369 return this->statements_
->may_fall_through();
3372 // Convert the case values and statements to the backend
3373 // representation. BREAK_LABEL is the label which break statements
3374 // should branch to. CASE_CONSTANTS is used to detect duplicate
3375 // constants. *CASES should be passed as an empty vector; the values
3376 // for this case will be added to it. If this is the default case,
3377 // *CASES will remain empty. This returns the statement to execute if
3378 // one of these cases is selected.
3381 Case_clauses::Case_clause::get_backend(Translate_context
* context
,
3382 Unnamed_label
* break_label
,
3383 Case_constants
* case_constants
,
3384 std::vector
<Bexpression
*>* cases
) const
3386 if (this->cases_
!= NULL
)
3388 go_assert(!this->is_default_
);
3389 for (Expression_list::const_iterator p
= this->cases_
->begin();
3390 p
!= this->cases_
->end();
3394 if (e
->classification() != Expression::EXPRESSION_INTEGER
)
3396 Numeric_constant nc
;
3398 if (!(*p
)->numeric_constant_value(&nc
) || !nc
.to_int(&ival
))
3400 // Something went wrong. This can happen with a
3401 // negative constant and an unsigned switch value.
3402 go_assert(saw_errors());
3405 go_assert(nc
.type() != NULL
);
3406 e
= Expression::make_integer_z(&ival
, nc
.type(), e
->location());
3410 std::pair
<Case_constants::iterator
, bool> ins
=
3411 case_constants
->insert(e
);
3414 // Value was already present.
3415 go_error_at(this->location_
, "duplicate case in switch");
3416 e
= Expression::make_error(this->location_
);
3418 cases
->push_back(e
->get_backend(context
));
3422 Bstatement
* statements
;
3423 if (this->statements_
== NULL
)
3427 Bblock
* bblock
= this->statements_
->get_backend(context
);
3428 statements
= context
->backend()->block_statement(bblock
);
3431 Bstatement
* break_stat
;
3432 if (this->is_fallthrough_
)
3435 break_stat
= break_label
->get_goto(context
, this->location_
);
3437 if (statements
== NULL
)
3439 else if (break_stat
== NULL
)
3442 return context
->backend()->compound_statement(statements
, break_stat
);
3445 // Dump the AST representation for a case clause
3448 Case_clauses::Case_clause::dump_clause(Ast_dump_context
* ast_dump_context
)
3451 ast_dump_context
->print_indent();
3452 if (this->is_default_
)
3454 ast_dump_context
->ostream() << "default:";
3458 ast_dump_context
->ostream() << "case ";
3459 ast_dump_context
->dump_expression_list(this->cases_
);
3460 ast_dump_context
->ostream() << ":" ;
3462 ast_dump_context
->dump_block(this->statements_
);
3463 if (this->is_fallthrough_
)
3465 ast_dump_context
->print_indent();
3466 ast_dump_context
->ostream() << " (fallthrough)" << dsuffix(location()) << std::endl
;
3470 // Class Case_clauses.
3475 Case_clauses::traverse(Traverse
* traverse
)
3477 for (Clauses::iterator p
= this->clauses_
.begin();
3478 p
!= this->clauses_
.end();
3481 if (p
->traverse(traverse
) == TRAVERSE_EXIT
)
3482 return TRAVERSE_EXIT
;
3484 return TRAVERSE_CONTINUE
;
3487 // Check whether all the case expressions are constant.
3490 Case_clauses::is_constant() const
3492 for (Clauses::const_iterator p
= this->clauses_
.begin();
3493 p
!= this->clauses_
.end();
3495 if (!p
->is_constant())
3500 // Lower case clauses for a nonconstant switch.
3503 Case_clauses::lower(Block
* b
, Temporary_statement
* val_temp
,
3504 Unnamed_label
* break_label
) const
3506 // The default case.
3507 const Case_clause
* default_case
= NULL
;
3509 // The label for the fallthrough of the previous case.
3510 Unnamed_label
* last_fallthrough_label
= NULL
;
3512 // The label for the start of the default case. This is used if the
3513 // case before the default case falls through.
3514 Unnamed_label
* default_start_label
= NULL
;
3516 // The label for the end of the default case. This normally winds
3517 // up as BREAK_LABEL, but it will be different if the default case
3519 Unnamed_label
* default_finish_label
= NULL
;
3521 for (Clauses::const_iterator p
= this->clauses_
.begin();
3522 p
!= this->clauses_
.end();
3525 // The label to use for the start of the statements for this
3526 // case. This is NULL unless the previous case falls through.
3527 Unnamed_label
* start_label
= last_fallthrough_label
;
3529 // The label to jump to after the end of the statements for this
3531 Unnamed_label
* finish_label
= break_label
;
3533 last_fallthrough_label
= NULL
;
3534 if (p
->is_fallthrough() && p
+ 1 != this->clauses_
.end())
3536 finish_label
= new Unnamed_label(p
->location());
3537 last_fallthrough_label
= finish_label
;
3540 if (!p
->is_default())
3541 p
->lower(b
, val_temp
, start_label
, finish_label
);
3544 // We have to move the default case to the end, so that we
3545 // only use it if all the other tests fail.
3547 default_start_label
= start_label
;
3548 default_finish_label
= finish_label
;
3552 if (default_case
!= NULL
)
3553 default_case
->lower(b
, val_temp
, default_start_label
,
3554 default_finish_label
);
3560 Case_clauses::determine_types(Type
* type
)
3562 for (Clauses::iterator p
= this->clauses_
.begin();
3563 p
!= this->clauses_
.end();
3565 p
->determine_types(type
);
3568 // Check types. Returns false if there was an error.
3571 Case_clauses::check_types(Type
* type
)
3574 for (Clauses::iterator p
= this->clauses_
.begin();
3575 p
!= this->clauses_
.end();
3578 if (!p
->check_types(type
))
3584 // Return true if these clauses may fall through to the statements
3585 // following the switch statement.
3588 Case_clauses::may_fall_through() const
3590 bool found_default
= false;
3591 for (Clauses::const_iterator p
= this->clauses_
.begin();
3592 p
!= this->clauses_
.end();
3595 if (p
->may_fall_through() && !p
->is_fallthrough())
3597 if (p
->is_default())
3598 found_default
= true;
3600 return !found_default
;
3603 // Convert the cases to the backend representation. This sets
3604 // *ALL_CASES and *ALL_STATEMENTS.
3607 Case_clauses::get_backend(Translate_context
* context
,
3608 Unnamed_label
* break_label
,
3609 std::vector
<std::vector
<Bexpression
*> >* all_cases
,
3610 std::vector
<Bstatement
*>* all_statements
) const
3612 Case_constants case_constants
;
3614 size_t c
= this->clauses_
.size();
3615 all_cases
->resize(c
);
3616 all_statements
->resize(c
);
3619 for (Clauses::const_iterator p
= this->clauses_
.begin();
3620 p
!= this->clauses_
.end();
3623 std::vector
<Bexpression
*> cases
;
3624 Bstatement
* stat
= p
->get_backend(context
, break_label
, &case_constants
,
3626 // The final clause can't fall through.
3627 if (i
== c
- 1 && p
->is_fallthrough())
3629 go_assert(saw_errors());
3630 stat
= context
->backend()->error_statement();
3632 (*all_cases
)[i
].swap(cases
);
3633 (*all_statements
)[i
] = stat
;
3637 // Dump the AST representation for case clauses (from a switch statement)
3640 Case_clauses::dump_clauses(Ast_dump_context
* ast_dump_context
) const
3642 for (Clauses::const_iterator p
= this->clauses_
.begin();
3643 p
!= this->clauses_
.end();
3645 p
->dump_clause(ast_dump_context
);
3648 // A constant switch statement. A Switch_statement is lowered to this
3649 // when all the cases are constants.
3651 class Constant_switch_statement
: public Statement
3654 Constant_switch_statement(Expression
* val
, Case_clauses
* clauses
,
3655 Unnamed_label
* break_label
,
3657 : Statement(STATEMENT_CONSTANT_SWITCH
, location
),
3658 val_(val
), clauses_(clauses
), break_label_(break_label
)
3663 do_traverse(Traverse
*);
3666 do_determine_types();
3669 do_check_types(Gogo
*);
3672 do_get_backend(Translate_context
*);
3675 do_dump_statement(Ast_dump_context
*) const;
3678 // The value to switch on.
3680 // The case clauses.
3681 Case_clauses
* clauses_
;
3682 // The break label, if needed.
3683 Unnamed_label
* break_label_
;
3689 Constant_switch_statement::do_traverse(Traverse
* traverse
)
3691 if (this->traverse_expression(traverse
, &this->val_
) == TRAVERSE_EXIT
)
3692 return TRAVERSE_EXIT
;
3693 return this->clauses_
->traverse(traverse
);
3699 Constant_switch_statement::do_determine_types()
3701 this->val_
->determine_type_no_context();
3702 this->clauses_
->determine_types(this->val_
->type());
3708 Constant_switch_statement::do_check_types(Gogo
*)
3710 if (!this->clauses_
->check_types(this->val_
->type()))
3711 this->set_is_error();
3714 // Convert to GENERIC.
3717 Constant_switch_statement::do_get_backend(Translate_context
* context
)
3719 Bexpression
* switch_val_expr
= this->val_
->get_backend(context
);
3721 Unnamed_label
* break_label
= this->break_label_
;
3722 if (break_label
== NULL
)
3723 break_label
= new Unnamed_label(this->location());
3725 std::vector
<std::vector
<Bexpression
*> > all_cases
;
3726 std::vector
<Bstatement
*> all_statements
;
3727 this->clauses_
->get_backend(context
, break_label
, &all_cases
,
3730 Bfunction
* bfunction
= context
->function()->func_value()->get_decl();
3731 Bstatement
* switch_statement
;
3732 switch_statement
= context
->backend()->switch_statement(bfunction
,
3737 Bstatement
* ldef
= break_label
->get_definition(context
);
3738 return context
->backend()->compound_statement(switch_statement
, ldef
);
3741 // Dump the AST representation for a constant switch statement.
3744 Constant_switch_statement::do_dump_statement(Ast_dump_context
* ast_dump_context
)
3747 ast_dump_context
->print_indent();
3748 ast_dump_context
->ostream() << "switch ";
3749 ast_dump_context
->dump_expression(this->val_
);
3751 if (ast_dump_context
->dump_subblocks())
3753 ast_dump_context
->ostream() << " {" << std::endl
;
3754 this->clauses_
->dump_clauses(ast_dump_context
);
3755 ast_dump_context
->ostream() << "}";
3758 ast_dump_context
->ostream() << std::endl
;
3761 // Class Switch_statement.
3766 Switch_statement::do_traverse(Traverse
* traverse
)
3768 if (this->val_
!= NULL
)
3770 if (this->traverse_expression(traverse
, &this->val_
) == TRAVERSE_EXIT
)
3771 return TRAVERSE_EXIT
;
3773 return this->clauses_
->traverse(traverse
);
3776 // Lower a Switch_statement to a Constant_switch_statement or a series
3777 // of if statements.
3780 Switch_statement::do_lower(Gogo
*, Named_object
*, Block
* enclosing
,
3781 Statement_inserter
*)
3783 Location loc
= this->location();
3785 if (this->val_
!= NULL
3786 && (this->val_
->is_error_expression()
3787 || this->val_
->type()->is_error()))
3789 go_assert(saw_errors());
3790 return Statement::make_error_statement(loc
);
3793 if (this->val_
!= NULL
3794 && this->val_
->type()->integer_type() != NULL
3795 && !this->clauses_
->empty()
3796 && this->clauses_
->is_constant())
3797 return new Constant_switch_statement(this->val_
, this->clauses_
,
3798 this->break_label_
, loc
);
3800 if (this->val_
!= NULL
3801 && !this->val_
->type()->is_comparable()
3802 && !Type::are_compatible_for_comparison(true, this->val_
->type(),
3803 Type::make_nil_type(), NULL
))
3805 go_error_at(this->val_
->location(),
3806 "cannot switch on value whose type that may not be compared");
3807 return Statement::make_error_statement(loc
);
3810 Block
* b
= new Block(enclosing
, loc
);
3812 if (this->clauses_
->empty())
3814 Expression
* val
= this->val_
;
3816 val
= Expression::make_boolean(true, loc
);
3817 return Statement::make_statement(val
, true);
3820 // var val_temp VAL_TYPE = VAL
3821 Expression
* val
= this->val_
;
3823 val
= Expression::make_boolean(true, loc
);
3825 Type
* type
= val
->type();
3826 if (type
->is_abstract())
3827 type
= type
->make_non_abstract_type();
3828 Temporary_statement
* val_temp
= Statement::make_temporary(type
, val
, loc
);
3829 b
->add_statement(val_temp
);
3831 this->clauses_
->lower(b
, val_temp
, this->break_label());
3833 Statement
* s
= Statement::make_unnamed_label_statement(this->break_label_
);
3834 b
->add_statement(s
);
3836 return Statement::make_block_statement(b
, loc
);
3839 // Return the break label for this switch statement, creating it if
3843 Switch_statement::break_label()
3845 if (this->break_label_
== NULL
)
3846 this->break_label_
= new Unnamed_label(this->location());
3847 return this->break_label_
;
3850 // Dump the AST representation for a switch statement.
3853 Switch_statement::do_dump_statement(Ast_dump_context
* ast_dump_context
) const
3855 ast_dump_context
->print_indent();
3856 ast_dump_context
->ostream() << "switch ";
3857 if (this->val_
!= NULL
)
3859 ast_dump_context
->dump_expression(this->val_
);
3861 if (ast_dump_context
->dump_subblocks())
3863 ast_dump_context
->ostream() << " {" << dsuffix(location()) << std::endl
;
3864 this->clauses_
->dump_clauses(ast_dump_context
);
3865 ast_dump_context
->print_indent();
3866 ast_dump_context
->ostream() << "}";
3868 ast_dump_context
->ostream() << std::endl
;
3871 // Return whether this switch may fall through.
3874 Switch_statement::do_may_fall_through() const
3876 if (this->clauses_
== NULL
)
3879 // If we have a break label, then some case needed it. That implies
3880 // that the switch statement as a whole can fall through.
3881 if (this->break_label_
!= NULL
)
3884 return this->clauses_
->may_fall_through();
3887 // Make a switch statement.
3890 Statement::make_switch_statement(Expression
* val
, Location location
)
3892 return new Switch_statement(val
, location
);
3895 // Class Type_case_clauses::Type_case_clause.
3900 Type_case_clauses::Type_case_clause::traverse(Traverse
* traverse
)
3902 if (!this->is_default_
3903 && ((traverse
->traverse_mask()
3904 & (Traverse::traverse_types
| Traverse::traverse_expressions
)) != 0)
3905 && Type::traverse(this->type_
, traverse
) == TRAVERSE_EXIT
)
3906 return TRAVERSE_EXIT
;
3907 if (this->statements_
!= NULL
)
3908 return this->statements_
->traverse(traverse
);
3909 return TRAVERSE_CONTINUE
;
3912 // Lower one clause in a type switch. Add statements to the block B.
3913 // The type descriptor we are switching on is in DESCRIPTOR_TEMP.
3914 // BREAK_LABEL is the label at the end of the type switch.
3915 // *STMTS_LABEL, if not NULL, is a label to put at the start of the
3919 Type_case_clauses::Type_case_clause::lower(Type
* switch_val_type
,
3921 Temporary_statement
* descriptor_temp
,
3922 Unnamed_label
* break_label
,
3923 Unnamed_label
** stmts_label
) const
3925 Location loc
= this->location_
;
3927 Unnamed_label
* next_case_label
= NULL
;
3928 if (!this->is_default_
)
3930 Type
* type
= this->type_
;
3933 if (switch_val_type
->interface_type() != NULL
3934 && !type
->is_nil_constant_as_type()
3935 && type
->interface_type() == NULL
3936 && !switch_val_type
->interface_type()->implements_interface(type
,
3940 go_error_at(this->location_
, "impossible type switch case");
3942 go_error_at(this->location_
, "impossible type switch case (%s)",
3946 Expression
* ref
= Expression::make_temporary_reference(descriptor_temp
,
3950 // The language permits case nil, which is of course a constant
3951 // rather than a type. It will appear here as an invalid
3953 if (type
->is_nil_constant_as_type())
3954 cond
= Expression::make_binary(OPERATOR_EQEQ
, ref
,
3955 Expression::make_nil(loc
),
3958 cond
= Runtime::make_call((type
->interface_type() == NULL
3959 ? Runtime::IFACETYPEEQ
3960 : Runtime::IFACET2IP
),
3962 Expression::make_type_descriptor(type
, loc
),
3965 Unnamed_label
* dest
;
3966 if (!this->is_fallthrough_
)
3968 // if !COND { goto NEXT_CASE_LABEL }
3969 next_case_label
= new Unnamed_label(Linemap::unknown_location());
3970 dest
= next_case_label
;
3971 cond
= Expression::make_unary(OPERATOR_NOT
, cond
, loc
);
3975 // if COND { goto STMTS_LABEL }
3976 go_assert(stmts_label
!= NULL
);
3977 if (*stmts_label
== NULL
)
3978 *stmts_label
= new Unnamed_label(Linemap::unknown_location());
3979 dest
= *stmts_label
;
3981 Block
* then_block
= new Block(b
, loc
);
3982 Statement
* s
= Statement::make_goto_unnamed_statement(dest
, loc
);
3983 then_block
->add_statement(s
);
3984 s
= Statement::make_if_statement(cond
, then_block
, NULL
, loc
);
3985 b
->add_statement(s
);
3988 if (this->statements_
!= NULL
3989 || (!this->is_fallthrough_
3990 && stmts_label
!= NULL
3991 && *stmts_label
!= NULL
))
3993 go_assert(!this->is_fallthrough_
);
3994 if (stmts_label
!= NULL
&& *stmts_label
!= NULL
)
3996 go_assert(!this->is_default_
);
3997 if (this->statements_
!= NULL
)
3998 (*stmts_label
)->set_location(this->statements_
->start_location());
3999 Statement
* s
= Statement::make_unnamed_label_statement(*stmts_label
);
4000 b
->add_statement(s
);
4001 *stmts_label
= NULL
;
4003 if (this->statements_
!= NULL
)
4004 b
->add_statement(Statement::make_block_statement(this->statements_
,
4008 if (this->is_fallthrough_
)
4009 go_assert(next_case_label
== NULL
);
4012 Location gloc
= (this->statements_
== NULL
4014 : this->statements_
->end_location());
4015 b
->add_statement(Statement::make_goto_unnamed_statement(break_label
,
4017 if (next_case_label
!= NULL
)
4020 Statement::make_unnamed_label_statement(next_case_label
);
4021 b
->add_statement(s
);
4026 // Return true if this type clause may fall through to the statements
4027 // following the switch.
4030 Type_case_clauses::Type_case_clause::may_fall_through() const
4032 if (this->is_fallthrough_
)
4034 // This case means that we automatically fall through to the
4035 // next case (it's used for T1 in case T1, T2:). It does not
4036 // mean that we fall through to the end of the type switch as a
4037 // whole. There is sure to be a next case and that next case
4038 // will determine whether we fall through to the statements
4039 // after the type switch.
4042 if (this->statements_
== NULL
)
4044 return this->statements_
->may_fall_through();
4047 // Dump the AST representation for a type case clause
4050 Type_case_clauses::Type_case_clause::dump_clause(
4051 Ast_dump_context
* ast_dump_context
) const
4053 ast_dump_context
->print_indent();
4054 if (this->is_default_
)
4056 ast_dump_context
->ostream() << "default:";
4060 ast_dump_context
->ostream() << "case ";
4061 ast_dump_context
->dump_type(this->type_
);
4062 ast_dump_context
->ostream() << ":" ;
4064 ast_dump_context
->dump_block(this->statements_
);
4065 if (this->is_fallthrough_
)
4067 ast_dump_context
->print_indent();
4068 ast_dump_context
->ostream() << " (fallthrough)" << std::endl
;
4072 // Class Type_case_clauses.
4077 Type_case_clauses::traverse(Traverse
* traverse
)
4079 for (Type_clauses::iterator p
= this->clauses_
.begin();
4080 p
!= this->clauses_
.end();
4083 if (p
->traverse(traverse
) == TRAVERSE_EXIT
)
4084 return TRAVERSE_EXIT
;
4086 return TRAVERSE_CONTINUE
;
4089 // Check for duplicate types.
4092 Type_case_clauses::check_duplicates() const
4094 typedef Unordered_set_hash(const Type
*, Type_hash_identical
,
4095 Type_identical
) Types_seen
;
4096 Types_seen types_seen
;
4097 for (Type_clauses::const_iterator p
= this->clauses_
.begin();
4098 p
!= this->clauses_
.end();
4101 Type
* t
= p
->type();
4104 if (t
->is_nil_constant_as_type())
4105 t
= Type::make_nil_type();
4106 std::pair
<Types_seen::iterator
, bool> ins
= types_seen
.insert(t
);
4108 go_error_at(p
->location(), "duplicate type in switch");
4112 // Lower the clauses in a type switch. Add statements to the block B.
4113 // The type descriptor we are switching on is in DESCRIPTOR_TEMP.
4114 // BREAK_LABEL is the label at the end of the type switch.
4117 Type_case_clauses::lower(Type
* switch_val_type
, Block
* b
,
4118 Temporary_statement
* descriptor_temp
,
4119 Unnamed_label
* break_label
) const
4121 const Type_case_clause
* default_case
= NULL
;
4123 Unnamed_label
* stmts_label
= NULL
;
4124 for (Type_clauses::const_iterator p
= this->clauses_
.begin();
4125 p
!= this->clauses_
.end();
4128 if (!p
->is_default())
4129 p
->lower(switch_val_type
, b
, descriptor_temp
, break_label
,
4133 // We are generating a series of tests, which means that we
4134 // need to move the default case to the end.
4138 go_assert(stmts_label
== NULL
);
4140 if (default_case
!= NULL
)
4141 default_case
->lower(switch_val_type
, b
, descriptor_temp
, break_label
,
4145 // Return true if these clauses may fall through to the statements
4146 // following the switch statement.
4149 Type_case_clauses::may_fall_through() const
4151 bool found_default
= false;
4152 for (Type_clauses::const_iterator p
= this->clauses_
.begin();
4153 p
!= this->clauses_
.end();
4156 if (p
->may_fall_through())
4158 if (p
->is_default())
4159 found_default
= true;
4161 return !found_default
;
4164 // Dump the AST representation for case clauses (from a switch statement)
4167 Type_case_clauses::dump_clauses(Ast_dump_context
* ast_dump_context
) const
4169 for (Type_clauses::const_iterator p
= this->clauses_
.begin();
4170 p
!= this->clauses_
.end();
4172 p
->dump_clause(ast_dump_context
);
4175 // Class Type_switch_statement.
4180 Type_switch_statement::do_traverse(Traverse
* traverse
)
4182 if (this->traverse_expression(traverse
, &this->expr_
) == TRAVERSE_EXIT
)
4183 return TRAVERSE_EXIT
;
4184 if (this->clauses_
!= NULL
)
4185 return this->clauses_
->traverse(traverse
);
4186 return TRAVERSE_CONTINUE
;
4189 // Lower a type switch statement to a series of if statements. The gc
4190 // compiler is able to generate a table in some cases. However, that
4191 // does not work for us because we may have type descriptors in
4192 // different shared libraries, so we can't compare them with simple
4193 // equality testing.
4196 Type_switch_statement::do_lower(Gogo
*, Named_object
*, Block
* enclosing
,
4197 Statement_inserter
*)
4199 const Location loc
= this->location();
4201 if (this->clauses_
!= NULL
)
4202 this->clauses_
->check_duplicates();
4204 Block
* b
= new Block(enclosing
, loc
);
4206 Type
* val_type
= this->expr_
->type();
4207 if (val_type
->interface_type() == NULL
)
4209 if (!val_type
->is_error())
4210 this->report_error(_("cannot type switch on non-interface value"));
4211 return Statement::make_error_statement(loc
);
4214 // var descriptor_temp DESCRIPTOR_TYPE
4215 Type
* descriptor_type
= Type::make_type_descriptor_ptr_type();
4216 Temporary_statement
* descriptor_temp
=
4217 Statement::make_temporary(descriptor_type
, NULL
, loc
);
4218 b
->add_statement(descriptor_temp
);
4220 // descriptor_temp = ifacetype(val_temp) FIXME: This should be
4222 bool is_empty
= val_type
->interface_type()->is_empty();
4223 Expression
* call
= Runtime::make_call((is_empty
4224 ? Runtime::EFACETYPE
4225 : Runtime::IFACETYPE
),
4226 loc
, 1, this->expr_
);
4227 Temporary_reference_expression
* lhs
=
4228 Expression::make_temporary_reference(descriptor_temp
, loc
);
4229 lhs
->set_is_lvalue();
4230 Statement
* s
= Statement::make_assignment(lhs
, call
, loc
);
4231 b
->add_statement(s
);
4233 if (this->clauses_
!= NULL
)
4234 this->clauses_
->lower(val_type
, b
, descriptor_temp
, this->break_label());
4236 s
= Statement::make_unnamed_label_statement(this->break_label_
);
4237 b
->add_statement(s
);
4239 return Statement::make_block_statement(b
, loc
);
4242 // Return whether this switch may fall through.
4245 Type_switch_statement::do_may_fall_through() const
4247 if (this->clauses_
== NULL
)
4250 // If we have a break label, then some case needed it. That implies
4251 // that the switch statement as a whole can fall through.
4252 if (this->break_label_
!= NULL
)
4255 return this->clauses_
->may_fall_through();
4258 // Return the break label for this type switch statement, creating it
4262 Type_switch_statement::break_label()
4264 if (this->break_label_
== NULL
)
4265 this->break_label_
= new Unnamed_label(this->location());
4266 return this->break_label_
;
4269 // Dump the AST representation for a type switch statement
4272 Type_switch_statement::do_dump_statement(Ast_dump_context
* ast_dump_context
)
4275 ast_dump_context
->print_indent();
4276 ast_dump_context
->ostream() << "switch ";
4277 if (!this->name_
.empty())
4278 ast_dump_context
->ostream() << this->name_
<< " = ";
4279 ast_dump_context
->dump_expression(this->expr_
);
4280 ast_dump_context
->ostream() << " .(type)";
4281 if (ast_dump_context
->dump_subblocks())
4283 ast_dump_context
->ostream() << " {" << dsuffix(location()) << std::endl
;
4284 this->clauses_
->dump_clauses(ast_dump_context
);
4285 ast_dump_context
->ostream() << "}";
4287 ast_dump_context
->ostream() << std::endl
;
4290 // Make a type switch statement.
4292 Type_switch_statement
*
4293 Statement::make_type_switch_statement(const std::string
& name
, Expression
* expr
,
4296 return new Type_switch_statement(name
, expr
, location
);
4299 // Class Send_statement.
4304 Send_statement::do_traverse(Traverse
* traverse
)
4306 if (this->traverse_expression(traverse
, &this->channel_
) == TRAVERSE_EXIT
)
4307 return TRAVERSE_EXIT
;
4308 return this->traverse_expression(traverse
, &this->val_
);
4314 Send_statement::do_determine_types()
4316 this->channel_
->determine_type_no_context();
4317 Type
* type
= this->channel_
->type();
4318 Type_context context
;
4319 if (type
->channel_type() != NULL
)
4320 context
.type
= type
->channel_type()->element_type();
4321 this->val_
->determine_type(&context
);
4327 Send_statement::do_check_types(Gogo
*)
4329 Type
* type
= this->channel_
->type();
4330 if (type
->is_error())
4332 this->set_is_error();
4335 Channel_type
* channel_type
= type
->channel_type();
4336 if (channel_type
== NULL
)
4338 go_error_at(this->location(), "left operand of %<<-%> must be channel");
4339 this->set_is_error();
4342 Type
* element_type
= channel_type
->element_type();
4343 if (!Type::are_assignable(element_type
, this->val_
->type(), NULL
))
4345 this->report_error(_("incompatible types in send"));
4348 if (!channel_type
->may_send())
4350 this->report_error(_("invalid send on receive-only channel"));
4355 // Flatten a send statement. We may need a temporary for interface
4359 Send_statement::do_flatten(Gogo
*, Named_object
*, Block
*,
4360 Statement_inserter
* inserter
)
4362 if (this->channel_
->is_error_expression()
4363 || this->channel_
->type()->is_error_type())
4365 go_assert(saw_errors());
4366 return Statement::make_error_statement(this->location());
4369 Type
* element_type
= this->channel_
->type()->channel_type()->element_type();
4370 if (!Type::are_identical(element_type
, this->val_
->type(), false, NULL
)
4371 && this->val_
->type()->interface_type() != NULL
4372 && !this->val_
->is_variable())
4374 Temporary_statement
* temp
=
4375 Statement::make_temporary(NULL
, this->val_
, this->location());
4376 inserter
->insert(temp
);
4377 this->val_
= Expression::make_temporary_reference(temp
,
4383 // Convert a send statement to the backend representation.
4386 Send_statement::do_get_backend(Translate_context
* context
)
4388 Location loc
= this->location();
4390 Channel_type
* channel_type
= this->channel_
->type()->channel_type();
4391 Type
* element_type
= channel_type
->element_type();
4392 Expression
* val
= Expression::convert_for_assignment(context
->gogo(),
4396 bool can_take_address
;
4397 switch (element_type
->base()->classification())
4399 case Type::TYPE_BOOLEAN
:
4400 case Type::TYPE_INTEGER
:
4401 case Type::TYPE_FUNCTION
:
4402 case Type::TYPE_POINTER
:
4403 case Type::TYPE_MAP
:
4404 case Type::TYPE_CHANNEL
:
4405 case Type::TYPE_FLOAT
:
4406 case Type::TYPE_COMPLEX
:
4407 case Type::TYPE_STRING
:
4408 case Type::TYPE_INTERFACE
:
4409 can_take_address
= false;
4412 case Type::TYPE_STRUCT
:
4413 can_take_address
= true;
4416 case Type::TYPE_ARRAY
:
4417 can_take_address
= !element_type
->is_slice_type();
4421 case Type::TYPE_ERROR
:
4422 case Type::TYPE_VOID
:
4423 case Type::TYPE_SINK
:
4424 case Type::TYPE_NIL
:
4425 case Type::TYPE_NAMED
:
4426 case Type::TYPE_FORWARD
:
4427 go_assert(saw_errors());
4428 return context
->backend()->error_statement();
4431 // Only try to take the address of a variable. We have already
4432 // moved variables to the heap, so this should not cause that to
4433 // happen unnecessarily.
4434 if (can_take_address
4435 && val
->var_expression() == NULL
4436 && val
->temporary_reference_expression() == NULL
)
4437 can_take_address
= false;
4439 Bstatement
* btemp
= NULL
;
4440 if (can_take_address
)
4442 // The function doesn't change the value, so just take its
4443 // address directly.
4444 val
= Expression::make_unary(OPERATOR_AND
, val
, loc
);
4448 // The value is not in a variable, or is small enough that it
4449 // might be in a register, and taking the address would push it
4450 // on the stack. Copy it into a temporary variable to take the
4452 Temporary_statement
* temp
= Statement::make_temporary(element_type
,
4454 Expression
* ref
= Expression::make_temporary_reference(temp
, loc
);
4455 val
= Expression::make_unary(OPERATOR_AND
, ref
, loc
);
4456 btemp
= temp
->get_backend(context
);
4459 Expression
* call
= Runtime::make_call(Runtime::CHANSEND
, loc
, 2,
4460 this->channel_
, val
);
4462 context
->gogo()->lower_expression(context
->function(), NULL
, &call
);
4463 Bexpression
* bcall
= call
->get_backend(context
);
4464 Bfunction
* bfunction
= context
->function()->func_value()->get_decl();
4465 Bstatement
* s
= context
->backend()->expression_statement(bfunction
, bcall
);
4470 return context
->backend()->compound_statement(btemp
, s
);
4473 // Dump the AST representation for a send statement
4476 Send_statement::do_dump_statement(Ast_dump_context
* ast_dump_context
) const
4478 ast_dump_context
->print_indent();
4479 ast_dump_context
->dump_expression(this->channel_
);
4480 ast_dump_context
->ostream() << " <- ";
4481 ast_dump_context
->dump_expression(this->val_
);
4482 ast_dump_context
->ostream() << dsuffix(location()) << std::endl
;
4485 // Make a send statement.
4488 Statement::make_send_statement(Expression
* channel
, Expression
* val
,
4491 return new Send_statement(channel
, val
, location
);
4494 // Class Select_clauses::Select_clause.
4499 Select_clauses::Select_clause::traverse(Traverse
* traverse
)
4501 if (!this->is_lowered_
4502 && (traverse
->traverse_mask()
4503 & (Traverse::traverse_types
| Traverse::traverse_expressions
)) != 0)
4505 if (this->channel_
!= NULL
)
4507 if (Expression::traverse(&this->channel_
, traverse
) == TRAVERSE_EXIT
)
4508 return TRAVERSE_EXIT
;
4510 if (this->val_
!= NULL
)
4512 if (Expression::traverse(&this->val_
, traverse
) == TRAVERSE_EXIT
)
4513 return TRAVERSE_EXIT
;
4515 if (this->closed_
!= NULL
)
4517 if (Expression::traverse(&this->closed_
, traverse
) == TRAVERSE_EXIT
)
4518 return TRAVERSE_EXIT
;
4521 if (this->statements_
!= NULL
)
4523 if (this->statements_
->traverse(traverse
) == TRAVERSE_EXIT
)
4524 return TRAVERSE_EXIT
;
4526 return TRAVERSE_CONTINUE
;
4529 // Lowering. We call a function to register this clause, and arrange
4530 // to set any variables in any receive clause.
4533 Select_clauses::Select_clause::lower(Gogo
* gogo
, Named_object
* function
,
4534 Block
* b
, Temporary_statement
* sel
)
4536 Location loc
= this->location_
;
4538 Expression
* selref
= Expression::make_temporary_reference(sel
, loc
);
4539 selref
= Expression::make_unary(OPERATOR_AND
, selref
, loc
);
4541 if (this->is_default_
)
4543 go_assert(this->channel_
== NULL
&& this->val_
== NULL
);
4544 this->lower_default(b
, selref
);
4545 this->is_lowered_
= true;
4549 // Evaluate the channel before the select statement.
4550 Temporary_statement
* channel_temp
= Statement::make_temporary(NULL
,
4553 b
->add_statement(channel_temp
);
4554 Expression
* chanref
= Expression::make_temporary_reference(channel_temp
,
4558 this->lower_send(b
, selref
, chanref
);
4560 this->lower_recv(gogo
, function
, b
, selref
, chanref
);
4562 // Now all references should be handled through the statements, not
4564 this->is_lowered_
= true;
4568 // Lower a default clause in a select statement.
4571 Select_clauses::Select_clause::lower_default(Block
* b
, Expression
* selref
)
4573 Location loc
= this->location_
;
4574 Expression
* call
= Runtime::make_call(Runtime::SELECTDEFAULT
, loc
, 1,
4576 b
->add_statement(Statement::make_statement(call
, true));
4579 // Lower a send clause in a select statement.
4582 Select_clauses::Select_clause::lower_send(Block
* b
, Expression
* selref
,
4583 Expression
* chanref
)
4585 Location loc
= this->location_
;
4587 Channel_type
* ct
= this->channel_
->type()->channel_type();
4591 Type
* valtype
= ct
->element_type();
4593 // Note that copying the value to a temporary here means that we
4594 // evaluate the send values in the required order.
4595 Temporary_statement
* val
= Statement::make_temporary(valtype
, this->val_
,
4597 b
->add_statement(val
);
4599 Expression
* valref
= Expression::make_temporary_reference(val
, loc
);
4600 Expression
* valaddr
= Expression::make_unary(OPERATOR_AND
, valref
, loc
);
4602 Expression
* call
= Runtime::make_call(Runtime::SELECTSEND
, loc
, 3, selref
,
4604 b
->add_statement(Statement::make_statement(call
, true));
4607 // Lower a receive clause in a select statement.
4610 Select_clauses::Select_clause::lower_recv(Gogo
* gogo
, Named_object
* function
,
4611 Block
* b
, Expression
* selref
,
4612 Expression
* chanref
)
4614 Location loc
= this->location_
;
4616 Channel_type
* ct
= this->channel_
->type()->channel_type();
4620 Type
* valtype
= ct
->element_type();
4621 Temporary_statement
* val
= Statement::make_temporary(valtype
, NULL
, loc
);
4622 b
->add_statement(val
);
4624 Expression
* valref
= Expression::make_temporary_reference(val
, loc
);
4625 Expression
* valaddr
= Expression::make_unary(OPERATOR_AND
, valref
, loc
);
4627 Temporary_statement
* closed_temp
= NULL
;
4630 if (this->closed_
== NULL
&& this->closedvar_
== NULL
)
4631 caddr
= Expression::make_nil(loc
);
4634 closed_temp
= Statement::make_temporary(Type::lookup_bool_type(), NULL
,
4636 b
->add_statement(closed_temp
);
4637 Expression
* cref
= Expression::make_temporary_reference(closed_temp
,
4639 caddr
= Expression::make_unary(OPERATOR_AND
, cref
, loc
);
4642 Expression
* call
= Runtime::make_call(Runtime::SELECTRECV
, loc
, 4, selref
,
4643 chanref
, valaddr
, caddr
);
4645 b
->add_statement(Statement::make_statement(call
, true));
4647 // If the block of statements is executed, arrange for the received
4648 // value to move from VAL to the place where the statements expect
4653 if (this->var_
!= NULL
)
4655 go_assert(this->val_
== NULL
);
4656 valref
= Expression::make_temporary_reference(val
, loc
);
4657 this->var_
->var_value()->set_init(valref
);
4658 this->var_
->var_value()->clear_type_from_chan_element();
4660 else if (this->val_
!= NULL
&& !this->val_
->is_sink_expression())
4662 init
= new Block(b
, loc
);
4663 valref
= Expression::make_temporary_reference(val
, loc
);
4664 init
->add_statement(Statement::make_assignment(this->val_
, valref
, loc
));
4667 if (this->closedvar_
!= NULL
)
4669 go_assert(this->closed_
== NULL
);
4670 Expression
* cref
= Expression::make_temporary_reference(closed_temp
,
4672 this->closedvar_
->var_value()->set_init(cref
);
4674 else if (this->closed_
!= NULL
&& !this->closed_
->is_sink_expression())
4677 init
= new Block(b
, loc
);
4678 Expression
* cref
= Expression::make_temporary_reference(closed_temp
,
4680 init
->add_statement(Statement::make_assignment(this->closed_
, cref
,
4686 gogo
->lower_block(function
, init
);
4688 if (this->statements_
!= NULL
)
4689 init
->add_statement(Statement::make_block_statement(this->statements_
,
4691 this->statements_
= init
;
4698 Select_clauses::Select_clause::determine_types()
4700 go_assert(this->is_lowered_
);
4701 if (this->statements_
!= NULL
)
4702 this->statements_
->determine_types();
4708 Select_clauses::Select_clause::check_types()
4710 if (this->is_default_
)
4713 Channel_type
* ct
= this->channel_
->type()->channel_type();
4716 go_error_at(this->channel_
->location(), "expected channel");
4720 if (this->is_send_
&& !ct
->may_send())
4721 go_error_at(this->location(), "invalid send on receive-only channel");
4722 else if (!this->is_send_
&& !ct
->may_receive())
4723 go_error_at(this->location(), "invalid receive on send-only channel");
4726 // Whether this clause may fall through to the statement which follows
4727 // the overall select statement.
4730 Select_clauses::Select_clause::may_fall_through() const
4732 if (this->statements_
== NULL
)
4734 return this->statements_
->may_fall_through();
4737 // Return the backend representation for the statements to execute.
4740 Select_clauses::Select_clause::get_statements_backend(
4741 Translate_context
* context
)
4743 if (this->statements_
== NULL
)
4745 Bblock
* bblock
= this->statements_
->get_backend(context
);
4746 return context
->backend()->block_statement(bblock
);
4749 // Dump the AST representation for a select case clause
4752 Select_clauses::Select_clause::dump_clause(
4753 Ast_dump_context
* ast_dump_context
) const
4755 ast_dump_context
->print_indent();
4756 if (this->is_default_
)
4758 ast_dump_context
->ostream() << "default:";
4762 ast_dump_context
->ostream() << "case " ;
4765 ast_dump_context
->dump_expression(this->channel_
);
4766 ast_dump_context
->ostream() << " <- " ;
4767 if (this->val_
!= NULL
)
4768 ast_dump_context
->dump_expression(this->val_
);
4772 if (this->val_
!= NULL
)
4773 ast_dump_context
->dump_expression(this->val_
);
4774 if (this->closed_
!= NULL
)
4776 // FIXME: can val_ == NULL and closed_ ! = NULL?
4777 ast_dump_context
->ostream() << " , " ;
4778 ast_dump_context
->dump_expression(this->closed_
);
4780 if (this->closedvar_
!= NULL
|| this->var_
!= NULL
)
4781 ast_dump_context
->ostream() << " := " ;
4783 ast_dump_context
->ostream() << " <- " ;
4784 ast_dump_context
->dump_expression(this->channel_
);
4786 ast_dump_context
->ostream() << ":" ;
4788 ast_dump_context
->dump_block(this->statements_
);
4791 // Class Select_clauses.
4796 Select_clauses::traverse(Traverse
* traverse
)
4798 for (Clauses::iterator p
= this->clauses_
.begin();
4799 p
!= this->clauses_
.end();
4802 if (p
->traverse(traverse
) == TRAVERSE_EXIT
)
4803 return TRAVERSE_EXIT
;
4805 return TRAVERSE_CONTINUE
;
4808 // Lowering. Here we pull out the channel and the send values, to
4809 // enforce the order of evaluation. We also add explicit send and
4810 // receive statements to the clauses.
4813 Select_clauses::lower(Gogo
* gogo
, Named_object
* function
, Block
* b
,
4814 Temporary_statement
* sel
)
4816 for (Clauses::iterator p
= this->clauses_
.begin();
4817 p
!= this->clauses_
.end();
4819 p
->lower(gogo
, function
, b
, sel
);
4825 Select_clauses::determine_types()
4827 for (Clauses::iterator p
= this->clauses_
.begin();
4828 p
!= this->clauses_
.end();
4830 p
->determine_types();
4836 Select_clauses::check_types()
4838 for (Clauses::iterator p
= this->clauses_
.begin();
4839 p
!= this->clauses_
.end();
4844 // Return whether these select clauses fall through to the statement
4845 // following the overall select statement.
4848 Select_clauses::may_fall_through() const
4850 for (Clauses::const_iterator p
= this->clauses_
.begin();
4851 p
!= this->clauses_
.end();
4853 if (p
->may_fall_through())
4858 // Convert to the backend representation. We have already accumulated
4859 // all the select information. Now we call selectgo, which will
4860 // return the index of the clause to execute.
4863 Select_clauses::get_backend(Translate_context
* context
,
4864 Temporary_statement
* sel
,
4865 Unnamed_label
*break_label
,
4868 size_t count
= this->clauses_
.size();
4869 std::vector
<std::vector
<Bexpression
*> > cases(count
);
4870 std::vector
<Bstatement
*> clauses(count
);
4872 Type
* int_type
= Type::lookup_integer_type("int");
4875 for (Clauses::iterator p
= this->clauses_
.begin();
4876 p
!= this->clauses_
.end();
4879 Expression
* index_expr
= Expression::make_integer_ul(i
, int_type
,
4881 cases
[i
].push_back(index_expr
->get_backend(context
));
4883 Bstatement
* s
= p
->get_statements_backend(context
);
4884 Location gloc
= (p
->statements() == NULL
4886 : p
->statements()->end_location());
4887 Bstatement
* g
= break_label
->get_goto(context
, gloc
);
4892 clauses
[i
] = context
->backend()->compound_statement(s
, g
);
4895 Expression
* selref
= Expression::make_temporary_reference(sel
, location
);
4896 selref
= Expression::make_unary(OPERATOR_AND
, selref
, location
);
4897 Expression
* call
= Runtime::make_call(Runtime::SELECTGO
, location
, 1,
4899 context
->gogo()->lower_expression(context
->function(), NULL
, &call
);
4900 Bexpression
* bcall
= call
->get_backend(context
);
4904 Bfunction
* bfunction
= context
->function()->func_value()->get_decl();
4905 return context
->backend()->expression_statement(bfunction
, bcall
);
4908 std::vector
<Bstatement
*> statements
;
4909 statements
.reserve(2);
4911 Bfunction
* bfunction
= context
->function()->func_value()->get_decl();
4912 Bstatement
* switch_stmt
= context
->backend()->switch_statement(bfunction
,
4917 statements
.push_back(switch_stmt
);
4919 Bstatement
* ldef
= break_label
->get_definition(context
);
4920 statements
.push_back(ldef
);
4922 return context
->backend()->statement_list(statements
);
4924 // Dump the AST representation for select clauses.
4927 Select_clauses::dump_clauses(Ast_dump_context
* ast_dump_context
) const
4929 for (Clauses::const_iterator p
= this->clauses_
.begin();
4930 p
!= this->clauses_
.end();
4932 p
->dump_clause(ast_dump_context
);
4935 // Class Select_statement.
4937 // Return the break label for this switch statement, creating it if
4941 Select_statement::break_label()
4943 if (this->break_label_
== NULL
)
4944 this->break_label_
= new Unnamed_label(this->location());
4945 return this->break_label_
;
4948 // Lower a select statement. This will still return a select
4949 // statement, but it will be modified to implement the order of
4950 // evaluation rules, and to include the send and receive statements as
4951 // explicit statements in the clauses.
4954 Select_statement::do_lower(Gogo
* gogo
, Named_object
* function
,
4955 Block
* enclosing
, Statement_inserter
*)
4957 if (this->is_lowered_
)
4960 Location loc
= this->location();
4962 Block
* b
= new Block(enclosing
, loc
);
4964 go_assert(this->sel_
== NULL
);
4966 int ncases
= this->clauses_
->size();
4967 Type
* selstruct_type
= Channel_type::select_type(ncases
);
4968 this->sel_
= Statement::make_temporary(selstruct_type
, NULL
, loc
);
4969 b
->add_statement(this->sel_
);
4971 int64_t selstruct_size
;
4972 if (!selstruct_type
->backend_type_size(gogo
, &selstruct_size
))
4974 go_assert(saw_errors());
4975 return Statement::make_error_statement(loc
);
4978 Expression
* ref
= Expression::make_temporary_reference(this->sel_
, loc
);
4979 ref
= Expression::make_unary(OPERATOR_AND
, ref
, loc
);
4980 Expression
* selstruct_size_expr
=
4981 Expression::make_integer_int64(selstruct_size
, NULL
, loc
);
4982 Expression
* size_expr
= Expression::make_integer_ul(ncases
, NULL
, loc
);
4983 Expression
* call
= Runtime::make_call(Runtime::NEWSELECT
, loc
, 3,
4984 ref
, selstruct_size_expr
, size_expr
);
4985 b
->add_statement(Statement::make_statement(call
, true));
4987 this->clauses_
->lower(gogo
, function
, b
, this->sel_
);
4988 this->is_lowered_
= true;
4989 b
->add_statement(this);
4991 return Statement::make_block_statement(b
, loc
);
4994 // Whether the select statement itself may fall through to the following
4998 Select_statement::do_may_fall_through() const
5000 // A select statement is terminating if no break statement
5001 // refers to it and all of its clauses are terminating.
5002 if (this->break_label_
!= NULL
)
5004 return this->clauses_
->may_fall_through();
5007 // Return the backend representation for a select statement.
5010 Select_statement::do_get_backend(Translate_context
* context
)
5012 return this->clauses_
->get_backend(context
, this->sel_
, this->break_label(),
5016 // Dump the AST representation for a select statement.
5019 Select_statement::do_dump_statement(Ast_dump_context
* ast_dump_context
) const
5021 ast_dump_context
->print_indent();
5022 ast_dump_context
->ostream() << "select";
5023 if (ast_dump_context
->dump_subblocks())
5025 ast_dump_context
->ostream() << " {" << dsuffix(location()) << std::endl
;
5026 this->clauses_
->dump_clauses(ast_dump_context
);
5027 ast_dump_context
->ostream() << "}";
5029 ast_dump_context
->ostream() << std::endl
;
5032 // Make a select statement.
5035 Statement::make_select_statement(Location location
)
5037 return new Select_statement(location
);
5040 // Class For_statement.
5045 For_statement::do_traverse(Traverse
* traverse
)
5047 if (this->init_
!= NULL
)
5049 if (this->init_
->traverse(traverse
) == TRAVERSE_EXIT
)
5050 return TRAVERSE_EXIT
;
5052 if (this->cond_
!= NULL
)
5054 if (this->traverse_expression(traverse
, &this->cond_
) == TRAVERSE_EXIT
)
5055 return TRAVERSE_EXIT
;
5057 if (this->post_
!= NULL
)
5059 if (this->post_
->traverse(traverse
) == TRAVERSE_EXIT
)
5060 return TRAVERSE_EXIT
;
5062 return this->statements_
->traverse(traverse
);
5065 // Lower a For_statement into if statements and gotos. Getting rid of
5066 // complex statements make it easier to handle garbage collection.
5069 For_statement::do_lower(Gogo
*, Named_object
*, Block
* enclosing
,
5070 Statement_inserter
*)
5073 Location loc
= this->location();
5075 Block
* b
= new Block(enclosing
, this->location());
5076 if (this->init_
!= NULL
)
5078 s
= Statement::make_block_statement(this->init_
,
5079 this->init_
->start_location());
5080 b
->add_statement(s
);
5083 Unnamed_label
* entry
= NULL
;
5084 if (this->cond_
!= NULL
)
5086 entry
= new Unnamed_label(this->location());
5087 b
->add_statement(Statement::make_goto_unnamed_statement(entry
, loc
));
5090 Unnamed_label
* top
= new Unnamed_label(this->location());
5091 top
->set_derived_from(this);
5092 b
->add_statement(Statement::make_unnamed_label_statement(top
));
5094 s
= Statement::make_block_statement(this->statements_
,
5095 this->statements_
->start_location());
5096 b
->add_statement(s
);
5098 Location end_loc
= this->statements_
->end_location();
5100 Unnamed_label
* cont
= this->continue_label_
;
5102 b
->add_statement(Statement::make_unnamed_label_statement(cont
));
5104 if (this->post_
!= NULL
)
5106 s
= Statement::make_block_statement(this->post_
,
5107 this->post_
->start_location());
5108 b
->add_statement(s
);
5109 end_loc
= this->post_
->end_location();
5112 if (this->cond_
== NULL
)
5113 b
->add_statement(Statement::make_goto_unnamed_statement(top
, end_loc
));
5116 b
->add_statement(Statement::make_unnamed_label_statement(entry
));
5118 Location cond_loc
= this->cond_
->location();
5119 Block
* then_block
= new Block(b
, cond_loc
);
5120 s
= Statement::make_goto_unnamed_statement(top
, cond_loc
);
5121 then_block
->add_statement(s
);
5123 s
= Statement::make_if_statement(this->cond_
, then_block
, NULL
, cond_loc
);
5124 b
->add_statement(s
);
5127 Unnamed_label
* brk
= this->break_label_
;
5129 b
->add_statement(Statement::make_unnamed_label_statement(brk
));
5131 b
->set_end_location(end_loc
);
5133 Statement
* bs
= Statement::make_block_statement(b
, loc
);
5134 bs
->block_statement()->set_is_lowered_for_statement();
5138 // Return the break label, creating it if necessary.
5141 For_statement::break_label()
5143 if (this->break_label_
== NULL
)
5144 this->break_label_
= new Unnamed_label(this->location());
5145 return this->break_label_
;
5148 // Return the continue LABEL_EXPR.
5151 For_statement::continue_label()
5153 if (this->continue_label_
== NULL
)
5154 this->continue_label_
= new Unnamed_label(this->location());
5155 return this->continue_label_
;
5158 // Set the break and continue labels a for statement. This is used
5159 // when lowering a for range statement.
5162 For_statement::set_break_continue_labels(Unnamed_label
* break_label
,
5163 Unnamed_label
* continue_label
)
5165 go_assert(this->break_label_
== NULL
&& this->continue_label_
== NULL
);
5166 this->break_label_
= break_label
;
5167 this->continue_label_
= continue_label
;
5170 // Whether the overall statement may fall through.
5173 For_statement::do_may_fall_through() const
5175 // A for loop is terminating if it has no condition and
5176 // no break statement.
5177 if(this->cond_
!= NULL
)
5179 if(this->break_label_
!= NULL
)
5184 // Dump the AST representation for a for statement.
5187 For_statement::do_dump_statement(Ast_dump_context
* ast_dump_context
) const
5189 if (this->init_
!= NULL
&& ast_dump_context
->dump_subblocks())
5191 ast_dump_context
->print_indent();
5192 ast_dump_context
->indent();
5193 ast_dump_context
->ostream() << "// INIT " << std::endl
;
5194 ast_dump_context
->dump_block(this->init_
);
5195 ast_dump_context
->unindent();
5197 ast_dump_context
->print_indent();
5198 ast_dump_context
->ostream() << "for ";
5199 if (this->cond_
!= NULL
)
5200 ast_dump_context
->dump_expression(this->cond_
);
5202 if (ast_dump_context
->dump_subblocks())
5204 ast_dump_context
->ostream() << " {" << std::endl
;
5205 ast_dump_context
->dump_block(this->statements_
);
5206 if (this->init_
!= NULL
)
5208 ast_dump_context
->print_indent();
5209 ast_dump_context
->ostream() << "// POST " << std::endl
;
5210 ast_dump_context
->dump_block(this->post_
);
5212 ast_dump_context
->unindent();
5214 ast_dump_context
->print_indent();
5215 ast_dump_context
->ostream() << "}";
5218 ast_dump_context
->ostream() << dsuffix(location()) << std::endl
;
5221 // Make a for statement.
5224 Statement::make_for_statement(Block
* init
, Expression
* cond
, Block
* post
,
5227 return new For_statement(init
, cond
, post
, location
);
5230 // Class For_range_statement.
5235 For_range_statement::do_traverse(Traverse
* traverse
)
5237 if (this->index_var_
!= NULL
)
5239 if (this->traverse_expression(traverse
, &this->index_var_
)
5241 return TRAVERSE_EXIT
;
5243 if (this->value_var_
!= NULL
)
5245 if (this->traverse_expression(traverse
, &this->value_var_
)
5247 return TRAVERSE_EXIT
;
5249 if (this->traverse_expression(traverse
, &this->range_
) == TRAVERSE_EXIT
)
5250 return TRAVERSE_EXIT
;
5251 return this->statements_
->traverse(traverse
);
5254 // Lower a for range statement. For simplicity we lower this into a
5255 // for statement, which will then be lowered in turn to goto
5259 For_range_statement::do_lower(Gogo
* gogo
, Named_object
*, Block
* enclosing
,
5260 Statement_inserter
*)
5262 Type
* range_type
= this->range_
->type();
5263 if (range_type
->points_to() != NULL
5264 && range_type
->points_to()->array_type() != NULL
5265 && !range_type
->points_to()->is_slice_type())
5266 range_type
= range_type
->points_to();
5269 Type
* value_type
= NULL
;
5270 if (range_type
->array_type() != NULL
)
5272 index_type
= Type::lookup_integer_type("int");
5273 value_type
= range_type
->array_type()->element_type();
5275 else if (range_type
->is_string_type())
5277 index_type
= Type::lookup_integer_type("int");
5278 value_type
= gogo
->lookup_global("rune")->type_value();
5280 else if (range_type
->map_type() != NULL
)
5282 index_type
= range_type
->map_type()->key_type();
5283 value_type
= range_type
->map_type()->val_type();
5285 else if (range_type
->channel_type() != NULL
)
5287 index_type
= range_type
->channel_type()->element_type();
5288 if (this->value_var_
!= NULL
)
5290 if (!this->value_var_
->type()->is_error())
5291 this->report_error(_("too many variables for range clause "
5293 return Statement::make_error_statement(this->location());
5298 this->report_error(_("range clause must have "
5299 "array, slice, string, map, or channel type"));
5300 return Statement::make_error_statement(this->location());
5303 Location loc
= this->location();
5304 Block
* temp_block
= new Block(enclosing
, loc
);
5306 Named_object
* range_object
= NULL
;
5307 Temporary_statement
* range_temp
= NULL
;
5308 Var_expression
* ve
= this->range_
->var_expression();
5310 range_object
= ve
->named_object();
5313 range_temp
= Statement::make_temporary(NULL
, this->range_
, loc
);
5314 temp_block
->add_statement(range_temp
);
5315 this->range_
= NULL
;
5318 Temporary_statement
* index_temp
= Statement::make_temporary(index_type
,
5320 temp_block
->add_statement(index_temp
);
5322 Temporary_statement
* value_temp
= NULL
;
5323 if (this->value_var_
!= NULL
)
5325 value_temp
= Statement::make_temporary(value_type
, NULL
, loc
);
5326 temp_block
->add_statement(value_temp
);
5329 Block
* body
= new Block(temp_block
, loc
);
5336 // Arrange to do a loop appropriate for the type. We will produce
5337 // for INIT ; COND ; POST {
5339 // INDEX = INDEX_TEMP
5340 // VALUE = VALUE_TEMP // If there is a value
5341 // original statements
5344 if (range_type
->is_slice_type())
5345 this->lower_range_slice(gogo
, temp_block
, body
, range_object
, range_temp
,
5346 index_temp
, value_temp
, &init
, &cond
, &iter_init
,
5348 else if (range_type
->array_type() != NULL
)
5349 this->lower_range_array(gogo
, temp_block
, body
, range_object
, range_temp
,
5350 index_temp
, value_temp
, &init
, &cond
, &iter_init
,
5352 else if (range_type
->is_string_type())
5353 this->lower_range_string(gogo
, temp_block
, body
, range_object
, range_temp
,
5354 index_temp
, value_temp
, &init
, &cond
, &iter_init
,
5356 else if (range_type
->map_type() != NULL
)
5357 this->lower_range_map(gogo
, range_type
->map_type(), temp_block
, body
,
5358 range_object
, range_temp
, index_temp
, value_temp
,
5359 &init
, &cond
, &iter_init
, &post
);
5360 else if (range_type
->channel_type() != NULL
)
5361 this->lower_range_channel(gogo
, temp_block
, body
, range_object
, range_temp
,
5362 index_temp
, value_temp
, &init
, &cond
, &iter_init
,
5367 if (iter_init
!= NULL
)
5368 body
->add_statement(Statement::make_block_statement(iter_init
, loc
));
5370 if (this->index_var_
!= NULL
)
5373 Expression
* index_ref
=
5374 Expression::make_temporary_reference(index_temp
, loc
);
5375 if (this->value_var_
== NULL
)
5376 assign
= Statement::make_assignment(this->index_var_
, index_ref
, loc
);
5379 Expression_list
* lhs
= new Expression_list();
5380 lhs
->push_back(this->index_var_
);
5381 lhs
->push_back(this->value_var_
);
5383 Expression_list
* rhs
= new Expression_list();
5384 rhs
->push_back(index_ref
);
5385 rhs
->push_back(Expression::make_temporary_reference(value_temp
, loc
));
5387 assign
= Statement::make_tuple_assignment(lhs
, rhs
, loc
);
5389 body
->add_statement(assign
);
5392 body
->add_statement(Statement::make_block_statement(this->statements_
, loc
));
5394 body
->set_end_location(this->statements_
->end_location());
5396 For_statement
* loop
= Statement::make_for_statement(init
, cond
, post
,
5398 loop
->add_statements(body
);
5399 loop
->set_break_continue_labels(this->break_label_
, this->continue_label_
);
5401 temp_block
->add_statement(loop
);
5403 return Statement::make_block_statement(temp_block
, loc
);
5406 // Return a reference to the range, which may be in RANGE_OBJECT or in
5410 For_range_statement::make_range_ref(Named_object
* range_object
,
5411 Temporary_statement
* range_temp
,
5414 if (range_object
!= NULL
)
5415 return Expression::make_var_reference(range_object
, loc
);
5417 return Expression::make_temporary_reference(range_temp
, loc
);
5420 // Return a call to the predeclared function FUNCNAME passing a
5421 // reference to the temporary variable ARG.
5424 For_range_statement::call_builtin(Gogo
* gogo
, const char* funcname
,
5428 Named_object
* no
= gogo
->lookup_global(funcname
);
5429 go_assert(no
!= NULL
&& no
->is_function_declaration());
5430 Expression
* func
= Expression::make_func_reference(no
, NULL
, loc
);
5431 Expression_list
* params
= new Expression_list();
5432 params
->push_back(arg
);
5433 return Expression::make_call(func
, params
, false, loc
);
5436 // Lower a for range over an array.
5439 For_range_statement::lower_range_array(Gogo
* gogo
,
5442 Named_object
* range_object
,
5443 Temporary_statement
* range_temp
,
5444 Temporary_statement
* index_temp
,
5445 Temporary_statement
* value_temp
,
5451 Location loc
= this->location();
5453 // The loop we generate:
5454 // len_temp := len(range)
5455 // range_temp := range
5456 // for index_temp = 0; index_temp < len_temp; index_temp++ {
5457 // value_temp = range_temp[index_temp]
5458 // index = index_temp
5459 // value = value_temp
5465 // len_temp = len(range)
5468 Block
* init
= new Block(enclosing
, loc
);
5470 Expression
* ref
= this->make_range_ref(range_object
, range_temp
, loc
);
5471 range_temp
= Statement::make_temporary(NULL
, ref
, loc
);
5472 Expression
* len_call
= this->call_builtin(gogo
, "len", ref
, loc
);
5473 Temporary_statement
* len_temp
= Statement::make_temporary(index_temp
->type(),
5475 init
->add_statement(range_temp
);
5476 init
->add_statement(len_temp
);
5478 Expression
* zexpr
= Expression::make_integer_ul(0, NULL
, loc
);
5480 Temporary_reference_expression
* tref
=
5481 Expression::make_temporary_reference(index_temp
, loc
);
5482 tref
->set_is_lvalue();
5483 Statement
* s
= Statement::make_assignment(tref
, zexpr
, loc
);
5484 init
->add_statement(s
);
5489 // index_temp < len_temp
5491 ref
= Expression::make_temporary_reference(index_temp
, loc
);
5492 Expression
* ref2
= Expression::make_temporary_reference(len_temp
, loc
);
5493 Expression
* lt
= Expression::make_binary(OPERATOR_LT
, ref
, ref2
, loc
);
5497 // Set *PITER_INIT to
5498 // value_temp = range[index_temp]
5500 Block
* iter_init
= NULL
;
5501 if (value_temp
!= NULL
)
5503 iter_init
= new Block(body_block
, loc
);
5505 ref
= Expression::make_temporary_reference(range_temp
, loc
);
5506 Expression
* ref2
= Expression::make_temporary_reference(index_temp
, loc
);
5507 Expression
* index
= Expression::make_index(ref
, ref2
, NULL
, NULL
, loc
);
5509 tref
= Expression::make_temporary_reference(value_temp
, loc
);
5510 tref
->set_is_lvalue();
5511 s
= Statement::make_assignment(tref
, index
, loc
);
5513 iter_init
->add_statement(s
);
5515 *piter_init
= iter_init
;
5520 Block
* post
= new Block(enclosing
, loc
);
5521 tref
= Expression::make_temporary_reference(index_temp
, loc
);
5522 tref
->set_is_lvalue();
5523 s
= Statement::make_inc_statement(tref
);
5524 post
->add_statement(s
);
5528 // Lower a for range over a slice.
5531 For_range_statement::lower_range_slice(Gogo
* gogo
,
5534 Named_object
* range_object
,
5535 Temporary_statement
* range_temp
,
5536 Temporary_statement
* index_temp
,
5537 Temporary_statement
* value_temp
,
5543 Location loc
= this->location();
5545 // The loop we generate:
5546 // for_temp := range
5547 // len_temp := len(for_temp)
5548 // for index_temp = 0; index_temp < len_temp; index_temp++ {
5549 // value_temp = for_temp[index_temp]
5550 // index = index_temp
5551 // value = value_temp
5555 // Using for_temp means that we don't need to check bounds when
5556 // fetching range_temp[index_temp].
5559 // range_temp := range
5561 // len_temp = len(range_temp)
5564 Block
* init
= new Block(enclosing
, loc
);
5566 Expression
* ref
= this->make_range_ref(range_object
, range_temp
, loc
);
5567 Temporary_statement
* for_temp
= Statement::make_temporary(NULL
, ref
, loc
);
5568 init
->add_statement(for_temp
);
5570 ref
= Expression::make_temporary_reference(for_temp
, loc
);
5571 Expression
* len_call
= this->call_builtin(gogo
, "len", ref
, loc
);
5572 Temporary_statement
* len_temp
= Statement::make_temporary(index_temp
->type(),
5574 init
->add_statement(len_temp
);
5576 Expression
* zexpr
= Expression::make_integer_ul(0, NULL
, loc
);
5578 Temporary_reference_expression
* tref
=
5579 Expression::make_temporary_reference(index_temp
, loc
);
5580 tref
->set_is_lvalue();
5581 Statement
* s
= Statement::make_assignment(tref
, zexpr
, loc
);
5582 init
->add_statement(s
);
5587 // index_temp < len_temp
5589 ref
= Expression::make_temporary_reference(index_temp
, loc
);
5590 Expression
* ref2
= Expression::make_temporary_reference(len_temp
, loc
);
5591 Expression
* lt
= Expression::make_binary(OPERATOR_LT
, ref
, ref2
, loc
);
5595 // Set *PITER_INIT to
5596 // value_temp = range[index_temp]
5598 Block
* iter_init
= NULL
;
5599 if (value_temp
!= NULL
)
5601 iter_init
= new Block(body_block
, loc
);
5603 ref
= Expression::make_temporary_reference(for_temp
, loc
);
5604 Expression
* ref2
= Expression::make_temporary_reference(index_temp
, loc
);
5605 Expression
* index
= Expression::make_index(ref
, ref2
, NULL
, NULL
, loc
);
5607 tref
= Expression::make_temporary_reference(value_temp
, loc
);
5608 tref
->set_is_lvalue();
5609 s
= Statement::make_assignment(tref
, index
, loc
);
5611 iter_init
->add_statement(s
);
5613 *piter_init
= iter_init
;
5618 Block
* post
= new Block(enclosing
, loc
);
5619 tref
= Expression::make_temporary_reference(index_temp
, loc
);
5620 tref
->set_is_lvalue();
5621 s
= Statement::make_inc_statement(tref
);
5622 post
->add_statement(s
);
5626 // Lower a for range over a string.
5629 For_range_statement::lower_range_string(Gogo
* gogo
,
5632 Named_object
* range_object
,
5633 Temporary_statement
* range_temp
,
5634 Temporary_statement
* index_temp
,
5635 Temporary_statement
* value_temp
,
5641 Location loc
= this->location();
5643 // The loop we generate:
5644 // len_temp := len(range)
5645 // var next_index_temp int
5646 // for index_temp = 0; index_temp < len_temp; index_temp = next_index_temp {
5647 // value_temp = rune(range[index_temp])
5648 // if value_temp < utf8.RuneSelf {
5649 // next_index_temp = index_temp + 1
5651 // value_temp, next_index_temp = decoderune(range, index_temp)
5653 // index = index_temp
5654 // value = value_temp
5659 // len_temp := len(range)
5660 // var next_index_temp int
5662 // var value_temp rune // if value_temp not passed in
5664 Block
* init
= new Block(enclosing
, loc
);
5666 Expression
* ref
= this->make_range_ref(range_object
, range_temp
, loc
);
5667 Call_expression
* call
= this->call_builtin(gogo
, "len", ref
, loc
);
5668 Temporary_statement
* len_temp
=
5669 Statement::make_temporary(index_temp
->type(), call
, loc
);
5670 init
->add_statement(len_temp
);
5672 Temporary_statement
* next_index_temp
=
5673 Statement::make_temporary(index_temp
->type(), NULL
, loc
);
5674 init
->add_statement(next_index_temp
);
5676 Temporary_reference_expression
* index_ref
=
5677 Expression::make_temporary_reference(index_temp
, loc
);
5678 index_ref
->set_is_lvalue();
5679 Expression
* zexpr
= Expression::make_integer_ul(0, index_temp
->type(), loc
);
5680 Statement
* s
= Statement::make_assignment(index_ref
, zexpr
, loc
);
5681 init
->add_statement(s
);
5684 if (value_temp
!= NULL
)
5685 rune_type
= value_temp
->type();
5688 rune_type
= gogo
->lookup_global("rune")->type_value();
5689 value_temp
= Statement::make_temporary(rune_type
, NULL
, loc
);
5690 init
->add_statement(value_temp
);
5696 // index_temp < len_temp
5698 index_ref
= Expression::make_temporary_reference(index_temp
, loc
);
5699 Expression
* len_ref
=
5700 Expression::make_temporary_reference(len_temp
, loc
);
5701 *pcond
= Expression::make_binary(OPERATOR_LT
, index_ref
, len_ref
, loc
);
5703 // Set *PITER_INIT to
5704 // value_temp = rune(range[index_temp])
5705 // if value_temp < utf8.RuneSelf {
5706 // next_index_temp = index_temp + 1
5708 // value_temp, next_index_temp = decoderune(range, index_temp)
5711 Block
* iter_init
= new Block(body_block
, loc
);
5713 ref
= this->make_range_ref(range_object
, range_temp
, loc
);
5714 index_ref
= Expression::make_temporary_reference(index_temp
, loc
);
5715 ref
= Expression::make_string_index(ref
, index_ref
, NULL
, loc
);
5716 ref
= Expression::make_cast(rune_type
, ref
, loc
);
5717 Temporary_reference_expression
* value_ref
=
5718 Expression::make_temporary_reference(value_temp
, loc
);
5719 value_ref
->set_is_lvalue();
5720 s
= Statement::make_assignment(value_ref
, ref
, loc
);
5721 iter_init
->add_statement(s
);
5723 value_ref
= Expression::make_temporary_reference(value_temp
, loc
);
5724 Expression
* rune_self
= Expression::make_integer_ul(0x80, rune_type
, loc
);
5725 Expression
* cond
= Expression::make_binary(OPERATOR_LT
, value_ref
, rune_self
,
5728 Block
* then_block
= new Block(iter_init
, loc
);
5730 Temporary_reference_expression
* lhs
=
5731 Expression::make_temporary_reference(next_index_temp
, loc
);
5732 lhs
->set_is_lvalue();
5733 index_ref
= Expression::make_temporary_reference(index_temp
, loc
);
5734 Expression
* one
= Expression::make_integer_ul(1, index_temp
->type(), loc
);
5735 Expression
* sum
= Expression::make_binary(OPERATOR_PLUS
, index_ref
, one
,
5737 s
= Statement::make_assignment(lhs
, sum
, loc
);
5738 then_block
->add_statement(s
);
5740 Block
* else_block
= new Block(iter_init
, loc
);
5742 ref
= this->make_range_ref(range_object
, range_temp
, loc
);
5743 index_ref
= Expression::make_temporary_reference(index_temp
, loc
);
5744 call
= Runtime::make_call(Runtime::DECODERUNE
, loc
, 2, ref
, index_ref
);
5746 value_ref
= Expression::make_temporary_reference(value_temp
, loc
);
5747 value_ref
->set_is_lvalue();
5748 Expression
* res
= Expression::make_call_result(call
, 0);
5749 s
= Statement::make_assignment(value_ref
, res
, loc
);
5750 else_block
->add_statement(s
);
5752 lhs
= Expression::make_temporary_reference(next_index_temp
, loc
);
5753 lhs
->set_is_lvalue();
5754 res
= Expression::make_call_result(call
, 1);
5755 s
= Statement::make_assignment(lhs
, res
, loc
);
5756 else_block
->add_statement(s
);
5758 s
= Statement::make_if_statement(cond
, then_block
, else_block
, loc
);
5759 iter_init
->add_statement(s
);
5761 *piter_init
= iter_init
;
5764 // index_temp = next_index_temp
5766 Block
* post
= new Block(enclosing
, loc
);
5768 index_ref
= Expression::make_temporary_reference(index_temp
, loc
);
5769 index_ref
->set_is_lvalue();
5770 ref
= Expression::make_temporary_reference(next_index_temp
, loc
);
5771 s
= Statement::make_assignment(index_ref
, ref
, loc
);
5773 post
->add_statement(s
);
5777 // Lower a for range over a map.
5780 For_range_statement::lower_range_map(Gogo
* gogo
,
5784 Named_object
* range_object
,
5785 Temporary_statement
* range_temp
,
5786 Temporary_statement
* index_temp
,
5787 Temporary_statement
* value_temp
,
5793 Location loc
= this->location();
5795 // The runtime uses a struct to handle ranges over a map. The
5796 // struct is built by Map_type::hiter_type for a specific map type.
5798 // The loop we generate:
5799 // var hiter map_iteration_struct
5800 // for mapiterinit(type, range, &hiter); hiter.key != nil; mapiternext(&hiter) {
5801 // index_temp = *hiter.key
5802 // value_temp = *hiter.val
5803 // index = index_temp
5804 // value = value_temp
5809 // var hiter map_iteration_struct
5810 // runtime.mapiterinit(type, range, &hiter)
5812 Block
* init
= new Block(enclosing
, loc
);
5814 Type
* map_iteration_type
= map_type
->hiter_type(gogo
);
5815 Temporary_statement
* hiter
= Statement::make_temporary(map_iteration_type
,
5817 init
->add_statement(hiter
);
5819 Expression
* p1
= Expression::make_type_descriptor(map_type
, loc
);
5820 Expression
* p2
= this->make_range_ref(range_object
, range_temp
, loc
);
5821 Expression
* ref
= Expression::make_temporary_reference(hiter
, loc
);
5822 Expression
* p3
= Expression::make_unary(OPERATOR_AND
, ref
, loc
);
5823 Expression
* call
= Runtime::make_call(Runtime::MAPITERINIT
, loc
, 3,
5825 init
->add_statement(Statement::make_statement(call
, true));
5832 ref
= Expression::make_temporary_reference(hiter
, loc
);
5833 ref
= Expression::make_field_reference(ref
, 0, loc
);
5834 Expression
* ne
= Expression::make_binary(OPERATOR_NOTEQ
, ref
,
5835 Expression::make_nil(loc
),
5839 // Set *PITER_INIT to
5840 // index_temp = *hiter.key
5841 // value_temp = *hiter.val
5843 Block
* iter_init
= new Block(body_block
, loc
);
5845 Expression
* lhs
= Expression::make_temporary_reference(index_temp
, loc
);
5846 Expression
* rhs
= Expression::make_temporary_reference(hiter
, loc
);
5847 rhs
= Expression::make_field_reference(ref
, 0, loc
);
5848 rhs
= Expression::make_dereference(ref
, Expression::NIL_CHECK_NOT_NEEDED
,
5850 Statement
* set
= Statement::make_assignment(lhs
, rhs
, loc
);
5851 iter_init
->add_statement(set
);
5853 if (value_temp
!= NULL
)
5855 lhs
= Expression::make_temporary_reference(value_temp
, loc
);
5856 rhs
= Expression::make_temporary_reference(hiter
, loc
);
5857 rhs
= Expression::make_field_reference(rhs
, 1, loc
);
5858 rhs
= Expression::make_dereference(rhs
, Expression::NIL_CHECK_NOT_NEEDED
,
5860 set
= Statement::make_assignment(lhs
, rhs
, loc
);
5861 iter_init
->add_statement(set
);
5864 *piter_init
= iter_init
;
5867 // mapiternext(&hiter)
5869 Block
* post
= new Block(enclosing
, loc
);
5871 ref
= Expression::make_temporary_reference(hiter
, loc
);
5872 p1
= Expression::make_unary(OPERATOR_AND
, ref
, loc
);
5873 call
= Runtime::make_call(Runtime::MAPITERNEXT
, loc
, 1, p1
);
5874 post
->add_statement(Statement::make_statement(call
, true));
5879 // Lower a for range over a channel.
5882 For_range_statement::lower_range_channel(Gogo
*,
5885 Named_object
* range_object
,
5886 Temporary_statement
* range_temp
,
5887 Temporary_statement
* index_temp
,
5888 Temporary_statement
* value_temp
,
5894 go_assert(value_temp
== NULL
);
5896 Location loc
= this->location();
5898 // The loop we generate:
5900 // index_temp, ok_temp = <-range
5904 // index = index_temp
5908 // We have no initialization code, no condition, and no post code.
5914 // Set *PITER_INIT to
5915 // index_temp, ok_temp = <-range
5920 Block
* iter_init
= new Block(body_block
, loc
);
5922 Temporary_statement
* ok_temp
=
5923 Statement::make_temporary(Type::lookup_bool_type(), NULL
, loc
);
5924 iter_init
->add_statement(ok_temp
);
5926 Expression
* cref
= this->make_range_ref(range_object
, range_temp
, loc
);
5927 Temporary_reference_expression
* iref
=
5928 Expression::make_temporary_reference(index_temp
, loc
);
5929 iref
->set_is_lvalue();
5930 Temporary_reference_expression
* oref
=
5931 Expression::make_temporary_reference(ok_temp
, loc
);
5932 oref
->set_is_lvalue();
5933 Statement
* s
= Statement::make_tuple_receive_assignment(iref
, oref
, cref
,
5935 iter_init
->add_statement(s
);
5937 Block
* then_block
= new Block(iter_init
, loc
);
5938 s
= Statement::make_break_statement(this->break_label(), loc
);
5939 then_block
->add_statement(s
);
5941 oref
= Expression::make_temporary_reference(ok_temp
, loc
);
5942 Expression
* cond
= Expression::make_unary(OPERATOR_NOT
, oref
, loc
);
5943 s
= Statement::make_if_statement(cond
, then_block
, NULL
, loc
);
5944 iter_init
->add_statement(s
);
5946 *piter_init
= iter_init
;
5949 // Return the break LABEL_EXPR.
5952 For_range_statement::break_label()
5954 if (this->break_label_
== NULL
)
5955 this->break_label_
= new Unnamed_label(this->location());
5956 return this->break_label_
;
5959 // Return the continue LABEL_EXPR.
5962 For_range_statement::continue_label()
5964 if (this->continue_label_
== NULL
)
5965 this->continue_label_
= new Unnamed_label(this->location());
5966 return this->continue_label_
;
5969 // Dump the AST representation for a for range statement.
5972 For_range_statement::do_dump_statement(Ast_dump_context
* ast_dump_context
) const
5975 ast_dump_context
->print_indent();
5976 ast_dump_context
->ostream() << "for ";
5977 ast_dump_context
->dump_expression(this->index_var_
);
5978 if (this->value_var_
!= NULL
)
5980 ast_dump_context
->ostream() << ", ";
5981 ast_dump_context
->dump_expression(this->value_var_
);
5984 ast_dump_context
->ostream() << " = range ";
5985 ast_dump_context
->dump_expression(this->range_
);
5986 if (ast_dump_context
->dump_subblocks())
5988 ast_dump_context
->ostream() << " {" << std::endl
;
5990 ast_dump_context
->indent();
5992 ast_dump_context
->dump_block(this->statements_
);
5994 ast_dump_context
->unindent();
5995 ast_dump_context
->print_indent();
5996 ast_dump_context
->ostream() << "}";
5998 ast_dump_context
->ostream() << dsuffix(location()) << std::endl
;
6001 // Make a for statement with a range clause.
6003 For_range_statement
*
6004 Statement::make_for_range_statement(Expression
* index_var
,
6005 Expression
* value_var
,
6009 return new For_range_statement(index_var
, value_var
, range
, location
);