gcc/ada/exp_ch6.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                              E X P _ C H 6                               --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2013, Free Software Foundation, Inc.         --
  10 --                                                                          --
  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 3,  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 COPYING3.  If not, go to --
  19 -- http://www.gnu.org/licenses for a complete copy of the license.          --
  20 --                                                                          --
  21 -- GNAT was originally developed  by the GNAT team at  New York University. --
  22 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  23 --                                                                          --
  24 ------------------------------------------------------------------------------
  25
  26 --  Expand routines for chapter 6 constructs
  27
  28 with Types; use Types;
  29
  30 package Exp_Ch6 is
  31
  32    procedure Expand_N_Extended_Return_Statement (N : Node_Id);
  33    procedure Expand_N_Function_Call             (N : Node_Id);
  34    procedure Expand_N_Procedure_Call_Statement  (N : Node_Id);
  35    procedure Expand_N_Simple_Return_Statement   (N : Node_Id);
  36    procedure Expand_N_Subprogram_Body           (N : Node_Id);
  37    procedure Expand_N_Subprogram_Body_Stub      (N : Node_Id);
  38    procedure Expand_N_Subprogram_Declaration    (N : Node_Id);
  39
  40    procedure Expand_Actuals (N : Node_Id; Subp : Entity_Id);
  41    --  For each actual of an in-out or out parameter which is a numeric
  42    --  (view) conversion of the form T (A), where A denotes a variable,
  43    --  we insert the declaration:
  44    --
  45    --    Temp : T[ := T (A)];
  46    --
  47    --  prior to the call. Then we replace the actual with a reference to Temp,
  48    --  and append the assignment:
  49    --
  50    --    A := TypeA (Temp);
  51    --
  52    --  after the call. Here TypeA is the actual type of variable A. For out
  53    --  parameters, the initial declaration has no expression. If A is not an
  54    --  entity name, we generate instead:
  55    --
  56    --    Var  : TypeA renames A;
  57    --    Temp : T := Var;       --  omitting expression for out parameter.
  58    --    ...
  59    --    Var := TypeA (Temp);
  60    --
  61    --  For other in-out parameters, we emit the required constraint checks
  62    --  before and/or after the call.
  63    --
  64    --  For all parameter modes, actuals that denote components and slices of
  65    --  packed arrays are expanded into suitable temporaries.
  66    --
  67    --  For non-scalar objects that are possibly unaligned, add call by copy
  68    --  code (copy in for IN and IN OUT, copy out for OUT and IN OUT).
  69
  70    procedure Expand_Call (N : Node_Id);
  71    --  This procedure contains common processing for Expand_N_Function_Call,
  72    --  Expand_N_Procedure_Statement, and Expand_N_Entry_Call.
  73
  74    procedure Expand_Contract_Cases
  75      (CCs     : Node_Id;
  76       Subp_Id : Entity_Id;
  77       Decls   : List_Id;
  78       Stmts   : in out List_Id);
  79    --  Given pragma Contract_Cases CCs, create the circuitry needed to evaluate
  80    --  case guards and trigger consequence expressions. Subp_Id is the related
  81    --  subprogram for which the pragma applies. Decls are the declarations of
  82    --  Subp_Id's body. All generated code is added to list Stmts. If Stmts is
  83    --  empty, a new list is created.
  84
  85    procedure Freeze_Subprogram (N : Node_Id);
  86    --  generate the appropriate expansions related to Subprogram freeze
  87    --  nodes (e.g. the filling of the corresponding Dispatch Table for
  88    --  Primitive Operations)
  89
  90    --  The following type defines the various forms of allocation used for the
  91    --  results of build-in-place function calls.
  92
  93    type BIP_Allocation_Form is
  94      (Unspecified,
  95       Caller_Allocation,
  96       Secondary_Stack,
  97       Global_Heap,
  98       User_Storage_Pool);
  99
 100    type BIP_Formal_Kind is
 101    --  Ada 2005 (AI-318-02): This type defines the kinds of implicit extra
 102    --  formals created for build-in-place functions. The order of these
 103    --  enumeration literals matches the order in which the formals are
 104    --  declared. See Sem_Ch6.Create_Extra_Formals.
 105
 106      (BIP_Alloc_Form,
 107       --  Present if result subtype is unconstrained or tagged. Indicates
 108       --  whether the return object is allocated by the caller or callee, and
 109       --  if the callee, whether to use the secondary stack or the heap. See
 110       --  Create_Extra_Formals.
 111
 112       BIP_Storage_Pool,
 113       --  Present if result subtype is unconstrained or tagged. If
 114       --  BIP_Alloc_Form = User_Storage_Pool, this is a pointer to the pool
 115       --  (of type access to Root_Storage_Pool'Class). Otherwise null.
 116
 117       BIP_Finalization_Master,
 118       --  Present if result type needs finalization. Pointer to caller's
 119       --  finalization master.
 120
 121       BIP_Task_Master,
 122       --  Present if result type contains tasks. Master associated with
 123       --  calling context.
 124
 125       BIP_Activation_Chain,
 126       --  Present if result type contains tasks. Caller's activation chain
 127
 128       BIP_Object_Access);
 129       --  Present for all build-in-place functions. Address at which to place
 130       --  the return object, or null if BIP_Alloc_Form indicates allocated by
 131       --  callee.
 132       --
 133       --  ??? We might also need to be able to pass in a constrained flag.
 134
 135    function BIP_Formal_Suffix (Kind : BIP_Formal_Kind) return String;
 136    --  Ada 2005 (AI-318-02): Returns a string to be used as the suffix of names
 137    --  for build-in-place formal parameters of the given kind.
 138
 139    function Build_In_Place_Formal
 140      (Func : Entity_Id;
 141       Kind : BIP_Formal_Kind) return Entity_Id;
 142    --  Ada 2005 (AI-318-02): Locates and returns the entity for the implicit
 143    --  build-in-place formal parameter of the given kind associated with the
 144    --  function Func, and returns its Entity_Id. It is a bug if not found; the
 145    --  caller should ensure this is called only when the extra formal exists.
 146
 147    function Is_Build_In_Place_Function (E : Entity_Id) return Boolean;
 148    --  Ada 2005 (AI-318-02): Returns True if E denotes a function, generic
 149    --  function, or access-to-function type whose result must be built in
 150    --  place; otherwise returns False. For Ada 2005, this is currently
 151    --  restricted to the set of functions whose result subtype is an inherently
 152    --  limited type. In Ada 95, this must be False for inherently limited
 153    --  result types (but currently returns False for all Ada 95 functions).
 154    --  Eventually we plan to support build-in-place for nonlimited types.
 155    --  Build-in-place is usually more efficient for large things, and less
 156    --  efficient for small things. However, we never use build-in-place if the
 157    --  convention is other than Ada, because that would disturb mixed-language
 158    --  programs. Note that for the non-inherently-limited cases, we must make
 159    --  the same decision for Ada 95 and 2005, so that mixed-dialect programs
 160    --  will work.
 161
 162    function Is_Build_In_Place_Function_Call (N : Node_Id) return Boolean;
 163    --  Ada 2005 (AI-318-02): Returns True if N denotes a call to a function
 164    --  that requires handling as a build-in-place call or is a qualified
 165    --  expression applied to such a call; otherwise returns False.
 166
 167    function Is_Null_Procedure (Subp : Entity_Id) return Boolean;
 168    --  Predicate to recognize stubbed procedures and null procedures, which
 169    --  can be inlined unconditionally in all cases.
 170
 171    procedure List_Inlining_Info;
 172    --  Generate listing of calls inlined by the frontend plus listing of
 173    --  calls to inline subprograms passed to the backend.
 174
 175    procedure Make_Build_In_Place_Call_In_Allocator
 176      (Allocator     : Node_Id;
 177       Function_Call : Node_Id);
 178    --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that
 179    --  occurs as the expression initializing an allocator, by passing access
 180    --  to the allocated object as an additional parameter of the function call.
 181    --  A new access object is declared that is initialized to the result of the
 182    --  allocator, passed to the function, and the allocator is rewritten to
 183    --  refer to that access object. Function_Call must denote either an
 184    --  N_Function_Call node for which Is_Build_In_Place_Call is True, or else
 185    --  an N_Qualified_Expression node applied to such a function call.
 186
 187    procedure Make_Build_In_Place_Call_In_Anonymous_Context
 188      (Function_Call : Node_Id);
 189    --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that
 190    --  occurs in a context that does not provide a separate object. A temporary
 191    --  object is created to act as the return object and an access to the
 192    --  temporary is passed as an additional parameter of the call. This occurs
 193    --  in contexts such as subprogram call actuals and object renamings.
 194    --  Function_Call must denote either an N_Function_Call node for which
 195    --  Is_Build_In_Place_Call is True, or else an N_Qualified_Expression node
 196    --  applied to such a function call.
 197
 198    procedure Make_Build_In_Place_Call_In_Assignment
 199      (Assign        : Node_Id;
 200       Function_Call : Node_Id);
 201    --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that
 202    --  occurs as the right-hand side of an assignment statement by passing
 203    --  access to the left-hand side as an additional parameter of the function
 204    --  call. Assign must denote a N_Assignment_Statement. Function_Call must
 205    --  denote either an N_Function_Call node for which Is_Build_In_Place_Call
 206    --  is True, or an N_Qualified_Expression node applied to such a function
 207    --  call.
 208
 209    procedure Make_Build_In_Place_Call_In_Object_Declaration
 210      (Object_Decl   : Node_Id;
 211       Function_Call : Node_Id);
 212    --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that
 213    --  occurs as the expression initializing an object declaration by
 214    --  passing access to the declared object as an additional parameter of the
 215    --  function call. Function_Call must denote either an N_Function_Call node
 216    --  for which Is_Build_In_Place_Call is True, or an N_Qualified_Expression
 217    --  node applied to such a function call.
 218
 219    procedure Make_CPP_Constructor_Call_In_Allocator
 220      (Allocator     : Node_Id;
 221       Function_Call : Node_Id);
 222    --  Handle a call to a CPP constructor that occurs as the expression that
 223    --  initializes an allocator, by passing access to the allocated object as
 224    --  an additional parameter of the constructor call. A new access object is
 225    --  declared that is initialized to the result of the allocator, passed to
 226    --  the constructor, and the allocator is rewritten to refer to that access
 227    --  object. Function_Call must denote a call to a CPP_Constructor function.
 228
 229    function Needs_BIP_Alloc_Form (Func_Id : Entity_Id) return Boolean;
 230    --  Ada 2005 (AI-318-02): Return True if the function needs an implicit
 231    --  BIP_Alloc_Form parameter (see type BIP_Formal_Kind).
 232
 233    function Needs_BIP_Finalization_Master (Func_Id : Entity_Id) return Boolean;
 234    --  Ada 2005 (AI-318-02): Return True if the result subtype of function
 235    --  Func_Id needs finalization actions.
 236
 237    function Needs_Result_Accessibility_Level
 238      (Func_Id : Entity_Id) return Boolean;
 239    --  Ada 2012 (AI05-0234): Return True if the function needs an implicit
 240    --  parameter to identify the accessibility level of the function result
 241    --  "determined by the point of call".
 242
 243    procedure Add_Extra_Actual_To_Call
 244      (Subprogram_Call : Node_Id;
 245       Extra_Formal    : Entity_Id;
 246       Extra_Actual    : Node_Id);
 247    --  Adds Extra_Actual as a named parameter association for the formal
 248    --  Extra_Formal in Subprogram_Call.
 249
 250 end Exp_Ch6;