1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2004 Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, USA. --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
25 ------------------------------------------------------------------------------
27 with Atree
; use Atree
;
28 with Checks
; use Checks
;
29 with Einfo
; use Einfo
;
30 with Errout
; use Errout
;
31 with Expander
; use Expander
;
32 with Exp_Util
; use Exp_Util
;
33 with Freeze
; use Freeze
;
34 with Lib
.Xref
; use Lib
.Xref
;
35 with Nlists
; use Nlists
;
36 with Nmake
; use Nmake
;
39 with Sem_Case
; use Sem_Case
;
40 with Sem_Ch3
; use Sem_Ch3
;
41 with Sem_Ch8
; use Sem_Ch8
;
42 with Sem_Disp
; use Sem_Disp
;
43 with Sem_Eval
; use Sem_Eval
;
44 with Sem_Res
; use Sem_Res
;
45 with Sem_Type
; use Sem_Type
;
46 with Sem_Util
; use Sem_Util
;
47 with Sem_Warn
; use Sem_Warn
;
48 with Stand
; use Stand
;
49 with Sinfo
; use Sinfo
;
50 with Targparm
; use Targparm
;
51 with Tbuild
; use Tbuild
;
52 with Uintp
; use Uintp
;
54 package body Sem_Ch5
is
56 Unblocked_Exit_Count
: Nat
:= 0;
57 -- This variable is used when processing if statements, case statements,
58 -- and block statements. It counts the number of exit points that are
59 -- not blocked by unconditional transfer instructions (for IF and CASE,
60 -- these are the branches of the conditional, for a block, they are the
61 -- statement sequence of the block, and the statement sequences of any
62 -- exception handlers that are part of the block. When processing is
63 -- complete, if this count is zero, it means that control cannot fall
64 -- through the IF, CASE or block statement. This is used for the
65 -- generation of warning messages. This variable is recursively saved
66 -- on entry to processing the construct, and restored on exit.
68 -----------------------
69 -- Local Subprograms --
70 -----------------------
72 procedure Analyze_Iteration_Scheme
(N
: Node_Id
);
74 procedure Check_Possible_Current_Value_Condition
(Cnode
: Node_Id
);
75 -- Cnode is N_If_Statement, N_Elsif_Part, or N_Iteration_Scheme
76 -- (the latter when a WHILE condition is present). This call checks
77 -- if Condition (Cnode) is of the form ([NOT] var op val), where var
78 -- is a simple object, val is known at compile time, and op is one
79 -- of the six relational operators. If this is the case, and the
80 -- Current_Value field of "var" is not set, then it is set to Cnode.
81 -- See Exp_Util.Set_Current_Value_Condition for further details.
83 ------------------------
84 -- Analyze_Assignment --
85 ------------------------
87 procedure Analyze_Assignment
(N
: Node_Id
) is
88 Lhs
: constant Node_Id
:= Name
(N
);
89 Rhs
: constant Node_Id
:= Expression
(N
);
95 procedure Diagnose_Non_Variable_Lhs
(N
: Node_Id
);
96 -- N is the node for the left hand side of an assignment, and it
97 -- is not a variable. This routine issues an appropriate diagnostic.
99 procedure Set_Assignment_Type
101 Opnd_Type
: in out Entity_Id
);
102 -- Opnd is either the Lhs or Rhs of the assignment, and Opnd_Type
103 -- is the nominal subtype. This procedure is used to deal with cases
104 -- where the nominal subtype must be replaced by the actual subtype.
106 -------------------------------
107 -- Diagnose_Non_Variable_Lhs --
108 -------------------------------
110 procedure Diagnose_Non_Variable_Lhs
(N
: Node_Id
) is
112 -- Not worth posting another error if left hand side already
113 -- flagged as being illegal in some respect
115 if Error_Posted
(N
) then
118 -- Some special bad cases of entity names
120 elsif Is_Entity_Name
(N
) then
121 if Ekind
(Entity
(N
)) = E_In_Parameter
then
123 ("assignment to IN mode parameter not allowed", N
);
125 -- Private declarations in a protected object are turned into
126 -- constants when compiling a protected function.
128 elsif Present
(Scope
(Entity
(N
)))
129 and then Is_Protected_Type
(Scope
(Entity
(N
)))
131 (Ekind
(Current_Scope
) = E_Function
133 Ekind
(Enclosing_Dynamic_Scope
(Current_Scope
)) = E_Function
)
136 ("protected function cannot modify protected object", N
);
138 elsif Ekind
(Entity
(N
)) = E_Loop_Parameter
then
140 ("assignment to loop parameter not allowed", N
);
144 ("left hand side of assignment must be a variable", N
);
147 -- For indexed components or selected components, test prefix
149 elsif Nkind
(N
) = N_Indexed_Component
then
150 Diagnose_Non_Variable_Lhs
(Prefix
(N
));
152 -- Another special case for assignment to discriminant.
154 elsif Nkind
(N
) = N_Selected_Component
then
155 if Present
(Entity
(Selector_Name
(N
)))
156 and then Ekind
(Entity
(Selector_Name
(N
))) = E_Discriminant
159 ("assignment to discriminant not allowed", N
);
161 Diagnose_Non_Variable_Lhs
(Prefix
(N
));
165 -- If we fall through, we have no special message to issue!
167 Error_Msg_N
("left hand side of assignment must be a variable", N
);
169 end Diagnose_Non_Variable_Lhs
;
171 -------------------------
172 -- Set_Assignment_Type --
173 -------------------------
175 procedure Set_Assignment_Type
177 Opnd_Type
: in out Entity_Id
)
180 Require_Entity
(Opnd
);
182 -- If the assignment operand is an in-out or out parameter, then we
183 -- get the actual subtype (needed for the unconstrained case).
184 -- If the operand is the actual in an entry declaration, then within
185 -- the accept statement it is replaced with a local renaming, which
186 -- may also have an actual subtype.
188 if Is_Entity_Name
(Opnd
)
189 and then (Ekind
(Entity
(Opnd
)) = E_Out_Parameter
190 or else Ekind
(Entity
(Opnd
)) =
192 or else Ekind
(Entity
(Opnd
)) =
193 E_Generic_In_Out_Parameter
195 (Ekind
(Entity
(Opnd
)) = E_Variable
196 and then Nkind
(Parent
(Entity
(Opnd
))) =
197 N_Object_Renaming_Declaration
198 and then Nkind
(Parent
(Parent
(Entity
(Opnd
)))) =
201 Opnd_Type
:= Get_Actual_Subtype
(Opnd
);
203 -- If assignment operand is a component reference, then we get the
204 -- actual subtype of the component for the unconstrained case.
207 (Nkind
(Opnd
) = N_Selected_Component
208 or else Nkind
(Opnd
) = N_Explicit_Dereference
)
209 and then not Is_Unchecked_Union
(Opnd_Type
)
211 Decl
:= Build_Actual_Subtype_Of_Component
(Opnd_Type
, Opnd
);
213 if Present
(Decl
) then
214 Insert_Action
(N
, Decl
);
215 Mark_Rewrite_Insertion
(Decl
);
217 Opnd_Type
:= Defining_Identifier
(Decl
);
218 Set_Etype
(Opnd
, Opnd_Type
);
219 Freeze_Itype
(Opnd_Type
, N
);
221 elsif Is_Constrained
(Etype
(Opnd
)) then
222 Opnd_Type
:= Etype
(Opnd
);
225 -- For slice, use the constrained subtype created for the slice
227 elsif Nkind
(Opnd
) = N_Slice
then
228 Opnd_Type
:= Etype
(Opnd
);
230 end Set_Assignment_Type
;
232 -- Start of processing for Analyze_Assignment
239 -- In the most general case, both Lhs and Rhs can be overloaded, and we
240 -- must compute the intersection of the possible types on each side.
242 if Is_Overloaded
(Lhs
) then
249 Get_First_Interp
(Lhs
, I
, It
);
251 while Present
(It
.Typ
) loop
252 if Has_Compatible_Type
(Rhs
, It
.Typ
) then
253 if T1
/= Any_Type
then
255 -- An explicit dereference is overloaded if the prefix
256 -- is. Try to remove the ambiguity on the prefix, the
257 -- error will be posted there if the ambiguity is real.
259 if Nkind
(Lhs
) = N_Explicit_Dereference
then
262 PI1
: Interp_Index
:= 0;
268 Get_First_Interp
(Prefix
(Lhs
), PI
, PIt
);
270 while Present
(PIt
.Typ
) loop
271 if Is_Access_Type
(PIt
.Typ
)
272 and then Has_Compatible_Type
273 (Rhs
, Designated_Type
(PIt
.Typ
))
277 Disambiguate
(Prefix
(Lhs
),
280 if PIt
= No_Interp
then
282 ("ambiguous left-hand side"
283 & " in assignment", Lhs
);
286 Resolve
(Prefix
(Lhs
), PIt
.Typ
);
296 Get_Next_Interp
(PI
, PIt
);
302 ("ambiguous left-hand side in assignment", Lhs
);
310 Get_Next_Interp
(I
, It
);
314 if T1
= Any_Type
then
316 ("no valid types for left-hand side for assignment", Lhs
);
323 if not Is_Variable
(Lhs
) then
324 Diagnose_Non_Variable_Lhs
(Lhs
);
327 elsif Is_Limited_Type
(T1
)
328 and then not Assignment_OK
(Lhs
)
329 and then not Assignment_OK
(Original_Node
(Lhs
))
332 ("left hand of assignment must not be limited type", Lhs
);
333 Explain_Limited_Type
(T1
, Lhs
);
337 -- Resolution may have updated the subtype, in case the left-hand
338 -- side is a private protected component. Use the correct subtype
339 -- to avoid scoping issues in the back-end.
342 Set_Assignment_Type
(Lhs
, T1
);
345 Check_Unset_Reference
(Rhs
);
347 -- Remaining steps are skipped if Rhs was syntactically in error
355 if Covers
(T1
, T2
) then
358 Wrong_Type
(Rhs
, Etype
(Lhs
));
362 Set_Assignment_Type
(Rhs
, T2
);
364 if Total_Errors_Detected
/= 0 then
374 if T1
= Any_Type
or else T2
= Any_Type
then
378 if (Is_Class_Wide_Type
(T2
) or else Is_Dynamically_Tagged
(Rhs
))
379 and then not Is_Class_Wide_Type
(T1
)
381 Error_Msg_N
("dynamically tagged expression not allowed!", Rhs
);
383 elsif Is_Class_Wide_Type
(T1
)
384 and then not Is_Class_Wide_Type
(T2
)
385 and then not Is_Tag_Indeterminate
(Rhs
)
386 and then not Is_Dynamically_Tagged
(Rhs
)
388 Error_Msg_N
("dynamically tagged expression required!", Rhs
);
391 -- Tag propagation is done only in semantics mode only. If expansion
392 -- is on, the rhs tag indeterminate function call has been expanded
393 -- and tag propagation would have happened too late, so the
394 -- propagation take place in expand_call instead.
396 if not Expander_Active
397 and then Is_Class_Wide_Type
(T1
)
398 and then Is_Tag_Indeterminate
(Rhs
)
400 Propagate_Tag
(Lhs
, Rhs
);
405 if Ada_Version
>= Ada_05
406 and then Nkind
(Rhs
) = N_Null
407 and then Is_Access_Type
(T1
)
408 and then not Assignment_OK
(Lhs
)
409 and then ((Is_Entity_Name
(Lhs
)
410 and then Can_Never_Be_Null
(Entity
(Lhs
)))
411 or else Can_Never_Be_Null
(Etype
(Lhs
)))
414 ("(Ada 2005) NULL not allowed in null-excluding objects", Lhs
);
417 if Is_Scalar_Type
(T1
) then
418 Apply_Scalar_Range_Check
(Rhs
, Etype
(Lhs
));
420 elsif Is_Array_Type
(T1
)
422 (Nkind
(Rhs
) /= N_Type_Conversion
423 or else Is_Constrained
(Etype
(Rhs
)))
425 -- Assignment verifies that the length of the Lsh and Rhs are equal,
426 -- but of course the indices do not have to match. If the right-hand
427 -- side is a type conversion to an unconstrained type, a length check
428 -- is performed on the expression itself during expansion. In rare
429 -- cases, the redundant length check is computed on an index type
430 -- with a different representation, triggering incorrect code in
433 Apply_Length_Check
(Rhs
, Etype
(Lhs
));
436 -- Discriminant checks are applied in the course of expansion
441 -- Note: modifications of the Lhs may only be recorded after
442 -- checks have been applied.
444 Note_Possible_Modification
(Lhs
);
446 -- ??? a real accessibility check is needed when ???
448 -- Post warning for useless assignment
450 if Warn_On_Redundant_Constructs
452 -- We only warn for source constructs
454 and then Comes_From_Source
(N
)
456 -- Where the entity is the same on both sides
458 and then Is_Entity_Name
(Lhs
)
459 and then Is_Entity_Name
(Original_Node
(Rhs
))
460 and then Entity
(Lhs
) = Entity
(Original_Node
(Rhs
))
462 -- But exclude the case where the right side was an operation
463 -- that got rewritten (e.g. JUNK + K, where K was known to be
464 -- zero). We don't want to warn in such a case, since it is
465 -- reasonable to write such expressions especially when K is
466 -- defined symbolically in some other package.
468 and then Nkind
(Original_Node
(Rhs
)) not in N_Op
471 ("?useless assignment of & to itself", N
, Entity
(Lhs
));
474 -- Check for non-allowed composite assignment
476 if not Support_Composite_Assign_On_Target
477 and then (Is_Array_Type
(T1
) or else Is_Record_Type
(T1
))
478 and then (not Has_Size_Clause
(T1
) or else Esize
(T1
) > 64)
480 Error_Msg_CRT
("composite assignment", N
);
483 -- One more step. Let's see if we have a simple assignment of a
484 -- known at compile time value to a simple variable. If so, we
485 -- can record the value as the current value providing that:
487 -- We still have a simple assignment statement (no expansion
488 -- activity has modified it in some peculiar manner)
490 -- The type is a discrete type
492 -- The assignment is to a named entity
494 -- The value is known at compile time
496 if Nkind
(N
) /= N_Assignment_Statement
497 or else not Is_Discrete_Type
(T1
)
498 or else not Is_Entity_Name
(Lhs
)
499 or else not Compile_Time_Known_Value
(Rhs
)
506 -- Capture value if save to do so
508 if Safe_To_Capture_Value
(N
, Ent
) then
509 Set_Current_Value
(Ent
, Rhs
);
511 end Analyze_Assignment
;
513 -----------------------------
514 -- Analyze_Block_Statement --
515 -----------------------------
517 procedure Analyze_Block_Statement
(N
: Node_Id
) is
518 Decls
: constant List_Id
:= Declarations
(N
);
519 Id
: constant Node_Id
:= Identifier
(N
);
520 HSS
: constant Node_Id
:= Handled_Statement_Sequence
(N
);
523 -- If no handled statement sequence is present, things are really
524 -- messed up, and we just return immediately (this is a defence
525 -- against previous errors).
531 -- Normal processing with HSS present
534 EH
: constant List_Id
:= Exception_Handlers
(HSS
);
535 Ent
: Entity_Id
:= Empty
;
538 Save_Unblocked_Exit_Count
: constant Nat
:= Unblocked_Exit_Count
;
539 -- Recursively save value of this global, will be restored on exit
542 -- Initialize unblocked exit count for statements of begin block
543 -- plus one for each excption handler that is present.
545 Unblocked_Exit_Count
:= 1;
548 Unblocked_Exit_Count
:= Unblocked_Exit_Count
+ List_Length
(EH
);
551 -- If a label is present analyze it and mark it as referenced
557 -- An error defense. If we have an identifier, but no entity,
558 -- then something is wrong. If we have previous errors, then
559 -- just remove the identifier and continue, otherwise raise
563 if Total_Errors_Detected
/= 0 then
564 Set_Identifier
(N
, Empty
);
570 Set_Ekind
(Ent
, E_Block
);
571 Generate_Reference
(Ent
, N
, ' ');
572 Generate_Definition
(Ent
);
574 if Nkind
(Parent
(Ent
)) = N_Implicit_Label_Declaration
then
575 Set_Label_Construct
(Parent
(Ent
), N
);
580 -- If no entity set, create a label entity
583 Ent
:= New_Internal_Entity
(E_Block
, Current_Scope
, Sloc
(N
), 'B');
584 Set_Identifier
(N
, New_Occurrence_Of
(Ent
, Sloc
(N
)));
588 Set_Etype
(Ent
, Standard_Void_Type
);
589 Set_Block_Node
(Ent
, Identifier
(N
));
592 if Present
(Decls
) then
593 Analyze_Declarations
(Decls
);
598 Process_End_Label
(HSS
, 'e', Ent
);
600 -- If exception handlers are present, then we indicate that
601 -- enclosing scopes contain a block with handlers. We only
602 -- need to mark non-generic scopes.
607 Set_Has_Nested_Block_With_Handler
(S
);
608 exit when Is_Overloadable
(S
)
609 or else Ekind
(S
) = E_Package
610 or else Is_Generic_Unit
(S
);
615 Check_References
(Ent
);
618 if Unblocked_Exit_Count
= 0 then
619 Unblocked_Exit_Count
:= Save_Unblocked_Exit_Count
;
620 Check_Unreachable_Code
(N
);
622 Unblocked_Exit_Count
:= Save_Unblocked_Exit_Count
;
625 end Analyze_Block_Statement
;
627 ----------------------------
628 -- Analyze_Case_Statement --
629 ----------------------------
631 procedure Analyze_Case_Statement
(N
: Node_Id
) is
633 Exp_Type
: Entity_Id
;
634 Exp_Btype
: Entity_Id
;
637 Others_Present
: Boolean;
639 Statements_Analyzed
: Boolean := False;
640 -- Set True if at least some statement sequences get analyzed.
641 -- If False on exit, means we had a serious error that prevented
642 -- full analysis of the case statement, and as a result it is not
643 -- a good idea to output warning messages about unreachable code.
645 Save_Unblocked_Exit_Count
: constant Nat
:= Unblocked_Exit_Count
;
646 -- Recursively save value of this global, will be restored on exit
648 procedure Non_Static_Choice_Error
(Choice
: Node_Id
);
649 -- Error routine invoked by the generic instantiation below when
650 -- the case statment has a non static choice.
652 procedure Process_Statements
(Alternative
: Node_Id
);
653 -- Analyzes all the statements associated to a case alternative.
654 -- Needed by the generic instantiation below.
656 package Case_Choices_Processing
is new
657 Generic_Choices_Processing
658 (Get_Alternatives
=> Alternatives
,
659 Get_Choices
=> Discrete_Choices
,
660 Process_Empty_Choice
=> No_OP
,
661 Process_Non_Static_Choice
=> Non_Static_Choice_Error
,
662 Process_Associated_Node
=> Process_Statements
);
663 use Case_Choices_Processing
;
664 -- Instantiation of the generic choice processing package
666 -----------------------------
667 -- Non_Static_Choice_Error --
668 -----------------------------
670 procedure Non_Static_Choice_Error
(Choice
: Node_Id
) is
673 ("choice given in case statement is not static!", Choice
);
674 end Non_Static_Choice_Error
;
676 ------------------------
677 -- Process_Statements --
678 ------------------------
680 procedure Process_Statements
(Alternative
: Node_Id
) is
681 Choices
: constant List_Id
:= Discrete_Choices
(Alternative
);
685 Unblocked_Exit_Count
:= Unblocked_Exit_Count
+ 1;
686 Statements_Analyzed
:= True;
688 -- An interesting optimization. If the case statement expression
689 -- is a simple entity, then we can set the current value within
690 -- an alternative if the alternative has one possible value.
694 -- when 2 | 3 => beta
695 -- when others => gamma
697 -- Here we know that N is initially 1 within alpha, but for beta
698 -- and gamma, we do not know anything more about the initial value.
700 if Is_Entity_Name
(Exp
) then
703 if Ekind
(Ent
) = E_Variable
705 Ekind
(Ent
) = E_In_Out_Parameter
707 Ekind
(Ent
) = E_Out_Parameter
709 if List_Length
(Choices
) = 1
710 and then Nkind
(First
(Choices
)) in N_Subexpr
711 and then Compile_Time_Known_Value
(First
(Choices
))
713 Set_Current_Value
(Entity
(Exp
), First
(Choices
));
716 Analyze_Statements
(Statements
(Alternative
));
718 -- After analyzing the case, set the current value to empty
719 -- since we won't know what it is for the next alternative
720 -- (unless reset by this same circuit), or after the case.
722 Set_Current_Value
(Entity
(Exp
), Empty
);
727 -- Case where expression is not an entity name of a variable
729 Analyze_Statements
(Statements
(Alternative
));
730 end Process_Statements
;
732 -- Table to record choices. Put after subprograms since we make
733 -- a call to Number_Of_Choices to get the right number of entries.
735 Case_Table
: Choice_Table_Type
(1 .. Number_Of_Choices
(N
));
737 -- Start of processing for Analyze_Case_Statement
740 Unblocked_Exit_Count
:= 0;
741 Exp
:= Expression
(N
);
742 Analyze_And_Resolve
(Exp
, Any_Discrete
);
743 Check_Unset_Reference
(Exp
);
744 Exp_Type
:= Etype
(Exp
);
745 Exp_Btype
:= Base_Type
(Exp_Type
);
747 -- The expression must be of a discrete type which must be determinable
748 -- independently of the context in which the expression occurs, but
749 -- using the fact that the expression must be of a discrete type.
750 -- Moreover, the type this expression must not be a character literal
751 -- (which is always ambiguous) or, for Ada-83, a generic formal type.
753 -- If error already reported by Resolve, nothing more to do
755 if Exp_Btype
= Any_Discrete
756 or else Exp_Btype
= Any_Type
760 elsif Exp_Btype
= Any_Character
then
762 ("character literal as case expression is ambiguous", Exp
);
765 elsif Ada_Version
= Ada_83
766 and then (Is_Generic_Type
(Exp_Btype
)
767 or else Is_Generic_Type
(Root_Type
(Exp_Btype
)))
770 ("(Ada 83) case expression cannot be of a generic type", Exp
);
774 -- If the case expression is a formal object of mode in out, then
775 -- treat it as having a nonstatic subtype by forcing use of the base
776 -- type (which has to get passed to Check_Case_Choices below). Also
777 -- use base type when the case expression is parenthesized.
779 if Paren_Count
(Exp
) > 0
780 or else (Is_Entity_Name
(Exp
)
781 and then Ekind
(Entity
(Exp
)) = E_Generic_In_Out_Parameter
)
783 Exp_Type
:= Exp_Btype
;
786 -- Call instantiated Analyze_Choices which does the rest of the work
789 (N
, Exp_Type
, Case_Table
, Last_Choice
, Dont_Care
, Others_Present
);
791 if Exp_Type
= Universal_Integer
and then not Others_Present
then
792 Error_Msg_N
("case on universal integer requires OTHERS choice", Exp
);
795 -- If all our exits were blocked by unconditional transfers of control,
796 -- then the entire CASE statement acts as an unconditional transfer of
797 -- control, so treat it like one, and check unreachable code. Skip this
798 -- test if we had serious errors preventing any statement analysis.
800 if Unblocked_Exit_Count
= 0 and then Statements_Analyzed
then
801 Unblocked_Exit_Count
:= Save_Unblocked_Exit_Count
;
802 Check_Unreachable_Code
(N
);
804 Unblocked_Exit_Count
:= Save_Unblocked_Exit_Count
;
807 if not Expander_Active
808 and then Compile_Time_Known_Value
(Expression
(N
))
809 and then Serious_Errors_Detected
= 0
812 Chosen
: constant Node_Id
:= Find_Static_Alternative
(N
);
816 Alt
:= First
(Alternatives
(N
));
818 while Present
(Alt
) loop
819 if Alt
/= Chosen
then
820 Remove_Warning_Messages
(Statements
(Alt
));
827 end Analyze_Case_Statement
;
829 ----------------------------
830 -- Analyze_Exit_Statement --
831 ----------------------------
833 -- If the exit includes a name, it must be the name of a currently open
834 -- loop. Otherwise there must be an innermost open loop on the stack,
835 -- to which the statement implicitly refers.
837 procedure Analyze_Exit_Statement
(N
: Node_Id
) is
838 Target
: constant Node_Id
:= Name
(N
);
839 Cond
: constant Node_Id
:= Condition
(N
);
840 Scope_Id
: Entity_Id
;
846 Check_Unreachable_Code
(N
);
849 if Present
(Target
) then
851 U_Name
:= Entity
(Target
);
853 if not In_Open_Scopes
(U_Name
) or else Ekind
(U_Name
) /= E_Loop
then
854 Error_Msg_N
("invalid loop name in exit statement", N
);
857 Set_Has_Exit
(U_Name
);
864 for J
in reverse 0 .. Scope_Stack
.Last
loop
865 Scope_Id
:= Scope_Stack
.Table
(J
).Entity
;
866 Kind
:= Ekind
(Scope_Id
);
869 and then (No
(Target
) or else Scope_Id
= U_Name
) then
870 Set_Has_Exit
(Scope_Id
);
873 elsif Kind
= E_Block
or else Kind
= E_Loop
then
878 ("cannot exit from program unit or accept statement", N
);
883 -- Verify that if present the condition is a Boolean expression
885 if Present
(Cond
) then
886 Analyze_And_Resolve
(Cond
, Any_Boolean
);
887 Check_Unset_Reference
(Cond
);
889 end Analyze_Exit_Statement
;
891 ----------------------------
892 -- Analyze_Goto_Statement --
893 ----------------------------
895 procedure Analyze_Goto_Statement
(N
: Node_Id
) is
896 Label
: constant Node_Id
:= Name
(N
);
897 Scope_Id
: Entity_Id
;
898 Label_Scope
: Entity_Id
;
901 Check_Unreachable_Code
(N
);
905 if Entity
(Label
) = Any_Id
then
908 elsif Ekind
(Entity
(Label
)) /= E_Label
then
909 Error_Msg_N
("target of goto statement must be a label", Label
);
912 elsif not Reachable
(Entity
(Label
)) then
913 Error_Msg_N
("target of goto statement is not reachable", Label
);
917 Label_Scope
:= Enclosing_Scope
(Entity
(Label
));
919 for J
in reverse 0 .. Scope_Stack
.Last
loop
920 Scope_Id
:= Scope_Stack
.Table
(J
).Entity
;
922 if Label_Scope
= Scope_Id
923 or else (Ekind
(Scope_Id
) /= E_Block
924 and then Ekind
(Scope_Id
) /= E_Loop
)
926 if Scope_Id
/= Label_Scope
then
928 ("cannot exit from program unit or accept statement", N
);
936 end Analyze_Goto_Statement
;
938 --------------------------
939 -- Analyze_If_Statement --
940 --------------------------
942 -- A special complication arises in the analysis of if statements.
944 -- The expander has circuitry to completely delete code that it
945 -- can tell will not be executed (as a result of compile time known
946 -- conditions). In the analyzer, we ensure that code that will be
947 -- deleted in this manner is analyzed but not expanded. This is
948 -- obviously more efficient, but more significantly, difficulties
949 -- arise if code is expanded and then eliminated (e.g. exception
950 -- table entries disappear). Similarly, itypes generated in deleted
951 -- code must be frozen from start, because the nodes on which they
952 -- depend will not be available at the freeze point.
954 procedure Analyze_If_Statement
(N
: Node_Id
) is
957 Save_Unblocked_Exit_Count
: constant Nat
:= Unblocked_Exit_Count
;
958 -- Recursively save value of this global, will be restored on exit
960 Save_In_Deleted_Code
: Boolean;
962 Del
: Boolean := False;
963 -- This flag gets set True if a True condition has been found,
964 -- which means that remaining ELSE/ELSIF parts are deleted.
966 procedure Analyze_Cond_Then
(Cnode
: Node_Id
);
967 -- This is applied to either the N_If_Statement node itself or
968 -- to an N_Elsif_Part node. It deals with analyzing the condition
969 -- and the THEN statements associated with it.
971 -----------------------
972 -- Analyze_Cond_Then --
973 -----------------------
975 procedure Analyze_Cond_Then
(Cnode
: Node_Id
) is
976 Cond
: constant Node_Id
:= Condition
(Cnode
);
977 Tstm
: constant List_Id
:= Then_Statements
(Cnode
);
980 Unblocked_Exit_Count
:= Unblocked_Exit_Count
+ 1;
981 Analyze_And_Resolve
(Cond
, Any_Boolean
);
982 Check_Unset_Reference
(Cond
);
983 Check_Possible_Current_Value_Condition
(Cnode
);
985 -- If already deleting, then just analyze then statements
988 Analyze_Statements
(Tstm
);
990 -- Compile time known value, not deleting yet
992 elsif Compile_Time_Known_Value
(Cond
) then
993 Save_In_Deleted_Code
:= In_Deleted_Code
;
995 -- If condition is True, then analyze the THEN statements
996 -- and set no expansion for ELSE and ELSIF parts.
998 if Is_True
(Expr_Value
(Cond
)) then
999 Analyze_Statements
(Tstm
);
1001 Expander_Mode_Save_And_Set
(False);
1002 In_Deleted_Code
:= True;
1004 -- If condition is False, analyze THEN with expansion off
1006 else -- Is_False (Expr_Value (Cond))
1007 Expander_Mode_Save_And_Set
(False);
1008 In_Deleted_Code
:= True;
1009 Analyze_Statements
(Tstm
);
1010 Expander_Mode_Restore
;
1011 In_Deleted_Code
:= Save_In_Deleted_Code
;
1014 -- Not known at compile time, not deleting, normal analysis
1017 Analyze_Statements
(Tstm
);
1019 end Analyze_Cond_Then
;
1021 -- Start of Analyze_If_Statement
1024 -- Initialize exit count for else statements. If there is no else
1025 -- part, this count will stay non-zero reflecting the fact that the
1026 -- uncovered else case is an unblocked exit.
1028 Unblocked_Exit_Count
:= 1;
1029 Analyze_Cond_Then
(N
);
1031 -- Now to analyze the elsif parts if any are present
1033 if Present
(Elsif_Parts
(N
)) then
1034 E
:= First
(Elsif_Parts
(N
));
1035 while Present
(E
) loop
1036 Analyze_Cond_Then
(E
);
1041 if Present
(Else_Statements
(N
)) then
1042 Analyze_Statements
(Else_Statements
(N
));
1045 -- If all our exits were blocked by unconditional transfers of control,
1046 -- then the entire IF statement acts as an unconditional transfer of
1047 -- control, so treat it like one, and check unreachable code.
1049 if Unblocked_Exit_Count
= 0 then
1050 Unblocked_Exit_Count
:= Save_Unblocked_Exit_Count
;
1051 Check_Unreachable_Code
(N
);
1053 Unblocked_Exit_Count
:= Save_Unblocked_Exit_Count
;
1057 Expander_Mode_Restore
;
1058 In_Deleted_Code
:= Save_In_Deleted_Code
;
1061 if not Expander_Active
1062 and then Compile_Time_Known_Value
(Condition
(N
))
1063 and then Serious_Errors_Detected
= 0
1065 if Is_True
(Expr_Value
(Condition
(N
))) then
1066 Remove_Warning_Messages
(Else_Statements
(N
));
1068 if Present
(Elsif_Parts
(N
)) then
1069 E
:= First
(Elsif_Parts
(N
));
1071 while Present
(E
) loop
1072 Remove_Warning_Messages
(Then_Statements
(E
));
1078 Remove_Warning_Messages
(Then_Statements
(N
));
1081 end Analyze_If_Statement
;
1083 ----------------------------------------
1084 -- Analyze_Implicit_Label_Declaration --
1085 ----------------------------------------
1087 -- An implicit label declaration is generated in the innermost
1088 -- enclosing declarative part. This is done for labels as well as
1089 -- block and loop names.
1091 -- Note: any changes in this routine may need to be reflected in
1092 -- Analyze_Label_Entity.
1094 procedure Analyze_Implicit_Label_Declaration
(N
: Node_Id
) is
1095 Id
: constant Node_Id
:= Defining_Identifier
(N
);
1098 Set_Ekind
(Id
, E_Label
);
1099 Set_Etype
(Id
, Standard_Void_Type
);
1100 Set_Enclosing_Scope
(Id
, Current_Scope
);
1101 end Analyze_Implicit_Label_Declaration
;
1103 ------------------------------
1104 -- Analyze_Iteration_Scheme --
1105 ------------------------------
1107 procedure Analyze_Iteration_Scheme
(N
: Node_Id
) is
1108 procedure Check_Controlled_Array_Attribute
(DS
: Node_Id
);
1109 -- If the bounds are given by a 'Range reference on a function call
1110 -- that returns a controlled array, introduce an explicit declaration
1111 -- to capture the bounds, so that the function result can be finalized
1112 -- in timely fashion.
1114 --------------------------------------
1115 -- Check_Controlled_Array_Attribute --
1116 --------------------------------------
1118 procedure Check_Controlled_Array_Attribute
(DS
: Node_Id
) is
1120 if Nkind
(DS
) = N_Attribute_Reference
1121 and then Is_Entity_Name
(Prefix
(DS
))
1122 and then Ekind
(Entity
(Prefix
(DS
))) = E_Function
1123 and then Is_Array_Type
(Etype
(Entity
(Prefix
(DS
))))
1126 Component_Type
(Etype
(Entity
(Prefix
(DS
)))))
1127 and then Expander_Active
1130 Loc
: constant Source_Ptr
:= Sloc
(N
);
1131 Arr
: constant Entity_Id
:=
1132 Etype
(Entity
(Prefix
(DS
)));
1133 Indx
: constant Entity_Id
:=
1134 Base_Type
(Etype
(First_Index
(Arr
)));
1135 Subt
: constant Entity_Id
:=
1136 Make_Defining_Identifier
1137 (Loc
, New_Internal_Name
('S'));
1142 Make_Subtype_Declaration
(Loc
,
1143 Defining_Identifier
=> Subt
,
1144 Subtype_Indication
=>
1145 Make_Subtype_Indication
(Loc
,
1146 Subtype_Mark
=> New_Reference_To
(Indx
, Loc
),
1148 Make_Range_Constraint
(Loc
,
1149 Relocate_Node
(DS
))));
1150 Insert_Before
(Parent
(N
), Decl
);
1154 Make_Attribute_Reference
(Loc
,
1155 Prefix
=> New_Reference_To
(Subt
, Loc
),
1156 Attribute_Name
=> Attribute_Name
(DS
)));
1160 end Check_Controlled_Array_Attribute
;
1162 -- Start of processing for Analyze_Iteration_Scheme
1165 -- For an infinite loop, there is no iteration scheme
1172 Cond
: constant Node_Id
:= Condition
(N
);
1175 -- For WHILE loop, verify that the condition is a Boolean
1176 -- expression and resolve and check it.
1178 if Present
(Cond
) then
1179 Analyze_And_Resolve
(Cond
, Any_Boolean
);
1180 Check_Unset_Reference
(Cond
);
1182 -- Else we have a FOR loop
1186 LP
: constant Node_Id
:= Loop_Parameter_Specification
(N
);
1187 Id
: constant Entity_Id
:= Defining_Identifier
(LP
);
1188 DS
: constant Node_Id
:= Discrete_Subtype_Definition
(LP
);
1193 -- We always consider the loop variable to be referenced,
1194 -- since the loop may be used just for counting purposes.
1196 Generate_Reference
(Id
, N
, ' ');
1198 -- Check for case of loop variable hiding a local
1199 -- variable (used later on to give a nice warning
1200 -- if the hidden variable is never assigned).
1203 H
: constant Entity_Id
:= Homonym
(Id
);
1206 and then Enclosing_Dynamic_Scope
(H
) =
1207 Enclosing_Dynamic_Scope
(Id
)
1208 and then Ekind
(H
) = E_Variable
1209 and then Is_Discrete_Type
(Etype
(H
))
1211 Set_Hiding_Loop_Variable
(H
, Id
);
1215 -- Now analyze the subtype definition
1223 -- The subtype indication may denote the completion
1224 -- of an incomplete type declaration.
1226 if Is_Entity_Name
(DS
)
1227 and then Present
(Entity
(DS
))
1228 and then Is_Type
(Entity
(DS
))
1229 and then Ekind
(Entity
(DS
)) = E_Incomplete_Type
1231 Set_Entity
(DS
, Get_Full_View
(Entity
(DS
)));
1232 Set_Etype
(DS
, Entity
(DS
));
1235 if not Is_Discrete_Type
(Etype
(DS
)) then
1236 Wrong_Type
(DS
, Any_Discrete
);
1237 Set_Etype
(DS
, Any_Type
);
1240 Check_Controlled_Array_Attribute
(DS
);
1241 Make_Index
(DS
, LP
);
1243 Set_Ekind
(Id
, E_Loop_Parameter
);
1244 Set_Etype
(Id
, Etype
(DS
));
1245 Set_Is_Known_Valid
(Id
, True);
1247 -- The loop is not a declarative part, so the only entity
1248 -- declared "within" must be frozen explicitly.
1251 Flist
: constant List_Id
:= Freeze_Entity
(Id
, Sloc
(N
));
1253 if Is_Non_Empty_List
(Flist
) then
1254 Insert_Actions
(N
, Flist
);
1258 -- Check for null or possibly null range and issue warning.
1259 -- We suppress such messages in generic templates and
1260 -- instances, because in practice they tend to be dubious
1263 if Nkind
(DS
) = N_Range
1264 and then Comes_From_Source
(N
)
1267 L
: constant Node_Id
:= Low_Bound
(DS
);
1268 H
: constant Node_Id
:= High_Bound
(DS
);
1278 Determine_Range
(L
, LOK
, Llo
, Lhi
);
1279 Determine_Range
(H
, HOK
, Hlo
, Hhi
);
1281 -- If range of loop is null, issue warning
1283 if (LOK
and HOK
) and then Llo
> Hhi
then
1285 -- Suppress the warning if inside a generic
1286 -- template or instance, since in practice
1287 -- they tend to be dubious in these cases since
1288 -- they can result from intended parametrization.
1290 if not Inside_A_Generic
1291 and then not In_Instance
1294 ("?loop range is null, loop will not execute",
1298 -- Since we know the range of the loop is null,
1299 -- set the appropriate flag to suppress any
1300 -- warnings that would otherwise be issued in
1301 -- the body of the loop that will not execute.
1302 -- We do this even in the generic case, since
1303 -- if it is dubious to warn on the null loop
1304 -- itself, it is certainly dubious to warn for
1305 -- conditions that occur inside it!
1307 Set_Is_Null_Loop
(Parent
(N
));
1309 -- The other case for a warning is a reverse loop
1310 -- where the upper bound is the integer literal
1311 -- zero or one, and the lower bound can be positive.
1313 -- For example, we have
1315 -- for J in reverse N .. 1 loop
1317 -- In practice, this is very likely to be a case
1318 -- of reversing the bounds incorrectly in the range.
1320 elsif Reverse_Present
(LP
)
1321 and then Nkind
(H
) = N_Integer_Literal
1322 and then (Intval
(H
) = Uint_0
1324 Intval
(H
) = Uint_1
)
1327 Error_Msg_N
("?loop range may be null", DS
);
1335 end Analyze_Iteration_Scheme
;
1341 -- Note: the semantic work required for analyzing labels (setting them as
1342 -- reachable) was done in a prepass through the statements in the block,
1343 -- so that forward gotos would be properly handled. See Analyze_Statements
1344 -- for further details. The only processing required here is to deal with
1345 -- optimizations that depend on an assumption of sequential control flow,
1346 -- since of course the occurrence of a label breaks this assumption.
1348 procedure Analyze_Label
(N
: Node_Id
) is
1349 pragma Warnings
(Off
, N
);
1351 Kill_Current_Values
;
1354 --------------------------
1355 -- Analyze_Label_Entity --
1356 --------------------------
1358 procedure Analyze_Label_Entity
(E
: Entity_Id
) is
1360 Set_Ekind
(E
, E_Label
);
1361 Set_Etype
(E
, Standard_Void_Type
);
1362 Set_Enclosing_Scope
(E
, Current_Scope
);
1363 Set_Reachable
(E
, True);
1364 end Analyze_Label_Entity
;
1366 ----------------------------
1367 -- Analyze_Loop_Statement --
1368 ----------------------------
1370 procedure Analyze_Loop_Statement
(N
: Node_Id
) is
1371 Id
: constant Node_Id
:= Identifier
(N
);
1375 if Present
(Id
) then
1377 -- Make name visible, e.g. for use in exit statements. Loop
1378 -- labels are always considered to be referenced.
1382 Generate_Reference
(Ent
, N
, ' ');
1383 Generate_Definition
(Ent
);
1385 -- If we found a label, mark its type. If not, ignore it, since it
1386 -- means we have a conflicting declaration, which would already have
1387 -- been diagnosed at declaration time. Set Label_Construct of the
1388 -- implicit label declaration, which is not created by the parser
1389 -- for generic units.
1391 if Ekind
(Ent
) = E_Label
then
1392 Set_Ekind
(Ent
, E_Loop
);
1394 if Nkind
(Parent
(Ent
)) = N_Implicit_Label_Declaration
then
1395 Set_Label_Construct
(Parent
(Ent
), N
);
1399 -- Case of no identifier present
1402 Ent
:= New_Internal_Entity
(E_Loop
, Current_Scope
, Sloc
(N
), 'L');
1403 Set_Etype
(Ent
, Standard_Void_Type
);
1404 Set_Parent
(Ent
, N
);
1407 -- Kill current values on entry to loop, since statements in body
1408 -- of loop may have been executed before the loop is entered.
1409 -- Similarly we kill values after the loop, since we do not know
1410 -- that the body of the loop was executed.
1412 Kill_Current_Values
;
1414 Analyze_Iteration_Scheme
(Iteration_Scheme
(N
));
1415 Analyze_Statements
(Statements
(N
));
1416 Process_End_Label
(N
, 'e', Ent
);
1418 Kill_Current_Values
;
1419 end Analyze_Loop_Statement
;
1421 ----------------------------
1422 -- Analyze_Null_Statement --
1423 ----------------------------
1425 -- Note: the semantics of the null statement is implemented by a single
1426 -- null statement, too bad everything isn't as simple as this!
1428 procedure Analyze_Null_Statement
(N
: Node_Id
) is
1429 pragma Warnings
(Off
, N
);
1432 end Analyze_Null_Statement
;
1434 ------------------------
1435 -- Analyze_Statements --
1436 ------------------------
1438 procedure Analyze_Statements
(L
: List_Id
) is
1443 -- The labels declared in the statement list are reachable from
1444 -- statements in the list. We do this as a prepass so that any
1445 -- goto statement will be properly flagged if its target is not
1446 -- reachable. This is not required, but is nice behavior!
1449 while Present
(S
) loop
1450 if Nkind
(S
) = N_Label
then
1451 Analyze
(Identifier
(S
));
1452 Lab
:= Entity
(Identifier
(S
));
1454 -- If we found a label mark it as reachable.
1456 if Ekind
(Lab
) = E_Label
then
1457 Generate_Definition
(Lab
);
1458 Set_Reachable
(Lab
);
1460 if Nkind
(Parent
(Lab
)) = N_Implicit_Label_Declaration
then
1461 Set_Label_Construct
(Parent
(Lab
), S
);
1464 -- If we failed to find a label, it means the implicit declaration
1465 -- of the label was hidden. A for-loop parameter can do this to
1466 -- a label with the same name inside the loop, since the implicit
1467 -- label declaration is in the innermost enclosing body or block
1471 Error_Msg_Sloc
:= Sloc
(Lab
);
1473 ("implicit label declaration for & is hidden#",
1481 -- Perform semantic analysis on all statements
1483 Conditional_Statements_Begin
;
1486 while Present
(S
) loop
1491 Conditional_Statements_End
;
1493 -- Make labels unreachable. Visibility is not sufficient, because
1494 -- labels in one if-branch for example are not reachable from the
1495 -- other branch, even though their declarations are in the enclosing
1496 -- declarative part.
1499 while Present
(S
) loop
1500 if Nkind
(S
) = N_Label
then
1501 Set_Reachable
(Entity
(Identifier
(S
)), False);
1506 end Analyze_Statements
;
1508 --------------------------------------------
1509 -- Check_Possible_Current_Value_Condition --
1510 --------------------------------------------
1512 procedure Check_Possible_Current_Value_Condition
(Cnode
: Node_Id
) is
1516 -- Loop to deal with (ignore for now) any NOT operators present
1518 Cond
:= Condition
(Cnode
);
1519 while Nkind
(Cond
) = N_Op_Not
loop
1520 Cond
:= Right_Opnd
(Cond
);
1523 -- Check possible relational operator
1525 if Nkind
(Cond
) = N_Op_Eq
1527 Nkind
(Cond
) = N_Op_Ne
1529 Nkind
(Cond
) = N_Op_Ge
1531 Nkind
(Cond
) = N_Op_Le
1533 Nkind
(Cond
) = N_Op_Gt
1535 Nkind
(Cond
) = N_Op_Lt
1537 if Compile_Time_Known_Value
(Right_Opnd
(Cond
))
1538 and then Nkind
(Left_Opnd
(Cond
)) = N_Identifier
1541 Ent
: constant Entity_Id
:= Entity
(Left_Opnd
(Cond
));
1544 if Ekind
(Ent
) = E_Variable
1546 Ekind
(Ent
) = E_Constant
1550 Ekind
(Ent
) = E_Loop_Parameter
1552 -- Here we have a case where the Current_Value field
1553 -- may need to be set. We set it if it is not already
1554 -- set to a compile time expression value.
1556 -- Note that this represents a decision that one
1557 -- condition blots out another previous one. That's
1558 -- certainly right if they occur at the same level.
1559 -- If the second one is nested, then the decision is
1560 -- neither right nor wrong (it would be equally OK
1561 -- to leave the outer one in place, or take the new
1562 -- inner one. Really we should record both, but our
1563 -- data structures are not that elaborate.
1565 if Nkind
(Current_Value
(Ent
)) not in N_Subexpr
then
1566 Set_Current_Value
(Ent
, Cnode
);
1572 end Check_Possible_Current_Value_Condition
;
1574 ----------------------------
1575 -- Check_Unreachable_Code --
1576 ----------------------------
1578 procedure Check_Unreachable_Code
(N
: Node_Id
) is
1579 Error_Loc
: Source_Ptr
;
1583 if Is_List_Member
(N
)
1584 and then Comes_From_Source
(N
)
1590 Nxt
:= Original_Node
(Next
(N
));
1592 -- If a label follows us, then we never have dead code, since
1593 -- someone could branch to the label, so we just ignore it.
1595 if Nkind
(Nxt
) = N_Label
then
1598 -- Otherwise see if we have a real statement following us
1601 and then Comes_From_Source
(Nxt
)
1602 and then Is_Statement
(Nxt
)
1604 -- Special very annoying exception. If we have a return that
1605 -- follows a raise, then we allow it without a warning, since
1606 -- the Ada RM annoyingly requires a useless return here!
1608 if Nkind
(Original_Node
(N
)) /= N_Raise_Statement
1609 or else Nkind
(Nxt
) /= N_Return_Statement
1611 -- The rather strange shenanigans with the warning message
1612 -- here reflects the fact that Kill_Dead_Code is very good
1613 -- at removing warnings in deleted code, and this is one
1614 -- warning we would prefer NOT to have removed :-)
1616 Error_Loc
:= Sloc
(Nxt
);
1618 -- If we have unreachable code, analyze and remove the
1619 -- unreachable code, since it is useless and we don't
1620 -- want to generate junk warnings.
1622 -- We skip this step if we are not in code generation mode.
1623 -- This is the one case where we remove dead code in the
1624 -- semantics as opposed to the expander, and we do not want
1625 -- to remove code if we are not in code generation mode,
1626 -- since this messes up the ASIS trees.
1628 -- Note that one might react by moving the whole circuit to
1629 -- exp_ch5, but then we lose the warning in -gnatc mode.
1631 if Operating_Mode
= Generate_Code
then
1635 -- Quit deleting when we have nothing more to delete
1636 -- or if we hit a label (since someone could transfer
1637 -- control to a label, so we should not delete it).
1639 exit when No
(Nxt
) or else Nkind
(Nxt
) = N_Label
;
1641 -- Statement/declaration is to be deleted
1645 Kill_Dead_Code
(Nxt
);
1649 -- Now issue the warning
1651 Error_Msg
("?unreachable code", Error_Loc
);
1654 -- If the unconditional transfer of control instruction is
1655 -- the last statement of a sequence, then see if our parent
1656 -- is one of the constructs for which we count unblocked exits,
1657 -- and if so, adjust the count.
1662 -- Statements in THEN part or ELSE part of IF statement
1664 if Nkind
(P
) = N_If_Statement
then
1667 -- Statements in ELSIF part of an IF statement
1669 elsif Nkind
(P
) = N_Elsif_Part
then
1671 pragma Assert
(Nkind
(P
) = N_If_Statement
);
1673 -- Statements in CASE statement alternative
1675 elsif Nkind
(P
) = N_Case_Statement_Alternative
then
1677 pragma Assert
(Nkind
(P
) = N_Case_Statement
);
1679 -- Statements in body of block
1681 elsif Nkind
(P
) = N_Handled_Sequence_Of_Statements
1682 and then Nkind
(Parent
(P
)) = N_Block_Statement
1686 -- Statements in exception handler in a block
1688 elsif Nkind
(P
) = N_Exception_Handler
1689 and then Nkind
(Parent
(P
)) = N_Handled_Sequence_Of_Statements
1690 and then Nkind
(Parent
(Parent
(P
))) = N_Block_Statement
1694 -- None of these cases, so return
1700 -- This was one of the cases we are looking for (i.e. the
1701 -- parent construct was IF, CASE or block) so decrement count.
1703 Unblocked_Exit_Count
:= Unblocked_Exit_Count
- 1;
1707 end Check_Unreachable_Code
;