https://gcc.gnu.org/g:d9ba2b857eb39ab52b1e2f93246af444e837dce4
commit r15-6517-gd9ba2b857eb39ab52b1e2f93246af444e837dce4
Author: Eric Botcazou <ebotca...@adacore.com>
Date: Sun Dec 1 11:46:46 2024 +0100
ada: Preliminary work in analysis and expansion of initialized allocators
This makes the expansion of the various cases of initialized allocators more
uniform by factoring out common processing as much as possible. This also
avoids giving the warning or error for a default-initialized allocator when
it is marked with No_Initialization. No functional changes.
gcc/ada/ChangeLog:
* checks.adb (Apply_Predicate_Check): Preserve Comes_From_Source.
* exp_ch4.adb (Expand_Allocator_Expression): Factor out common code
for the various cases. Also delay applying the 2nd predicate check.
In the default case, defer to Make_Build_In_Place_Call_In_Allocator
entirely in the build-in-place case.
* sem_ch4.adb (Analyze_Allocator): Do not give the warning or error
for a default-initialized allocator with No_Initialization.
Diff:
---
gcc/ada/checks.adb | 4 +
gcc/ada/exp_ch4.adb | 309 ++++++++++++++++++++++++++--------------------------
gcc/ada/sem_ch4.adb | 6 +-
3 files changed, 160 insertions(+), 159 deletions(-)
diff --git a/gcc/ada/checks.adb b/gcc/ada/checks.adb
index c30c99b31aa2..467661bf4186 100644
--- a/gcc/ada/checks.adb
+++ b/gcc/ada/checks.adb
@@ -2893,6 +2893,10 @@ package body Checks is
if Deref then
Expr := Make_Explicit_Dereference (Loc, Prefix => Expr);
+
+ -- Preserve Comes_From_Source for Predicate_Check_In_Scope
+
+ Preserve_Comes_From_Source (Expr, N);
end if;
-- Disable checks to prevent an infinite recursion
diff --git a/gcc/ada/exp_ch4.adb b/gcc/ada/exp_ch4.adb
index 6f54b5c04b4f..7fda62216612 100644
--- a/gcc/ada/exp_ch4.adb
+++ b/gcc/ada/exp_ch4.adb
@@ -566,18 +566,25 @@ package body Exp_Ch4 is
PtrT : constant Entity_Id := Etype (N);
DesigT : constant Entity_Id := Designated_Type (PtrT);
Special_Return : constant Boolean := For_Special_Return_Object (N);
+ Static_Match : constant Boolean :=
+ not Is_Constrained (DesigT)
+ or else Subtypes_Statically_Match (T, DesigT);
procedure Build_Aggregate_In_Place (Temp : Entity_Id; Typ : Entity_Id);
-- If Exp is an aggregate to build in place, build the declaration of
- -- Temp with Typ and initializing expression an uninitialized allocator
- -- for Etype (Exp), then perform an in-place aggregate assignment of Exp
- -- into the allocated memory.
+ -- object Temp with Typ and initialization expression an uninitialized
+ -- allocator for Etype (Exp), then perform in-place aggregate assignment
+ -- of Exp into the newly allocated memory.
procedure Build_Explicit_Assignment (Temp : Entity_Id; Typ : Entity_Id);
-- If Exp is a conditional expression whose expansion has been delayed,
- -- build the declaration of Temp with Typ and initializing expression an
- -- uninitialized allocator for Etype (Exp), then perform an assignment
- -- of Exp into the allocated memory.
+ -- build the declaration of object Temp with Typ and initialization
+ -- expression an uninitialized allocator for Etype (Exp), then perform
+ -- assignment of Exp into the newly allocated memory.
+
+ procedure Build_Simple_Allocation (Temp : Entity_Id; Typ : Entity_Id);
+ -- Build the declaration of object Temp with Typ and initialization
+ -- expression the allocator N.
------------------------------
-- Build_Aggregate_In_Place --
@@ -587,6 +594,7 @@ package body Exp_Ch4 is
Temp_Decl : constant Node_Id :=
Make_Object_Declaration (Loc,
Defining_Identifier => Temp,
+ Constant_Present => True,
Object_Definition => New_Occurrence_Of (Typ, Loc),
Expression =>
Make_Allocator (Loc,
@@ -625,6 +633,7 @@ package body Exp_Ch4 is
Temp_Decl : constant Node_Id :=
Make_Object_Declaration (Loc,
Defining_Identifier => Temp,
+ Constant_Present => True,
Object_Definition => New_Occurrence_Of (Typ, Loc),
Expression =>
Make_Allocator (Loc,
@@ -653,15 +662,32 @@ package body Exp_Ch4 is
Insert_Action (N, Assign);
end Build_Explicit_Assignment;
+ -----------------------------
+ -- Build_Simple_Allocation --
+ -----------------------------
+
+ procedure Build_Simple_Allocation (Temp : Entity_Id; Typ : Entity_Id) is
+ New_N : constant Node_Id := Relocate_Node (N);
+ Temp_Decl : constant Node_Id :=
+ Make_Object_Declaration (Loc,
+ Defining_Identifier => Temp,
+ Constant_Present => True,
+ Object_Definition => New_Occurrence_Of (Typ, Loc),
+ Expression => New_N);
+
+ begin
+ -- Avoid recursion in the mechanism
+
+ Set_Analyzed (New_N);
+
+ Insert_Action (N, Temp_Decl);
+ end Build_Simple_Allocation;
+
-- Local variables
- Adj_Call : Node_Id;
Aggr_In_Place : Boolean;
Container_Aggr : Boolean;
Delayed_Cond_Expr : Boolean;
- Node : Node_Id;
- Temp : Entity_Id;
- Temp_Decl : Node_Id;
TagT : Entity_Id := Empty;
-- Type used as source for tag assignment
@@ -669,6 +695,9 @@ package body Exp_Ch4 is
TagR : Node_Id := Empty;
-- Target reference for tag assignment
+ Temp : Entity_Id;
+ -- Temporary used to hold the result of the allocator
+
-- Start of processing for Expand_Allocator_Expression
begin
@@ -688,31 +717,42 @@ package body Exp_Ch4 is
-- both constraints. First check against the type of the qualified
-- expression.
+ -- Note that we delay applying predicate checks, because this may
+ -- cause the creation of a temporary, which is illegal for limited
+ -- types and just inefficient in the other cases.
+
Apply_Constraint_Check (Exp, T, No_Sliding => True);
- Aggr_In_Place := Is_Delayed_Aggregate (Exp);
- Delayed_Cond_Expr := Is_Delayed_Conditional_Expression (Exp);
- Container_Aggr := Nkind (Exp) = N_Aggregate
- and then Has_Aspect (T, Aspect_Aggregate);
+ if Do_Range_Check (Exp) then
+ Generate_Range_Check (Exp, T, CE_Range_Check_Failed);
+ end if;
- -- If the expression is an aggregate to be built in place, then we need
- -- to delay applying predicate checks, because this would result in the
- -- creation of a temporary, which is illegal for limited types and just
- -- inefficient in the other cases. Likewise for a conditional expression
- -- whose expansion has been delayed and for container aggregates.
+ -- A check is also needed in cases where the designated subtype is
+ -- constrained and differs from the subtype given in the qualified
+ -- expression. Note that the check on the qualified expression does
+ -- not allow sliding, but this check does (a relaxation from Ada 83).
- if not Aggr_In_Place
- and then not Delayed_Cond_Expr
- and then not Container_Aggr
- then
- Apply_Predicate_Check (Exp, T);
+ if not Static_Match then
+ Apply_Constraint_Check (Exp, DesigT, No_Sliding => False);
+
+ if Do_Range_Check (Exp) then
+ Generate_Range_Check (Exp, DesigT, CE_Range_Check_Failed);
+ end if;
+ end if;
+
+ -- Propagate Constraint_Error and return
+
+ if Nkind (Exp) = N_Raise_Constraint_Error then
+ Rewrite (N, New_Copy (Exp));
+ Set_Etype (N, PtrT);
+ return;
end if;
-- Check that any anonymous access discriminants are suitable
-- for use in an allocator.
- -- Note: This check is performed here instead of during analysis so that
- -- we can check against the fully resolved etype of Exp.
+ -- Note: This check is performed here instead of during analysis
+ -- so that we can check against the fully resolved Etype of Exp.
if Is_Entity_Name (Exp)
and then Has_Anonymous_Access_Discriminant (Etype (Exp))
@@ -740,49 +780,22 @@ package body Exp_Ch4 is
end if;
end if;
- if Do_Range_Check (Exp) then
- Generate_Range_Check (Exp, T, CE_Range_Check_Failed);
- end if;
-
- -- A check is also needed in cases where the designated subtype is
- -- constrained and differs from the subtype given in the qualified
- -- expression. Note that the check on the qualified expression does
- -- not allow sliding, but this check does (a relaxation from Ada 83).
-
- if Is_Constrained (DesigT)
- and then not Subtypes_Statically_Match (T, DesigT)
- then
- Apply_Constraint_Check (Exp, DesigT, No_Sliding => False);
-
- Apply_Predicate_Check (Exp, DesigT);
-
- if Do_Range_Check (Exp) then
- Generate_Range_Check (Exp, DesigT, CE_Range_Check_Failed);
- end if;
- end if;
-
- if Nkind (Exp) = N_Raise_Constraint_Error then
- Rewrite (N, New_Copy (Exp));
- Set_Etype (N, PtrT);
- return;
- end if;
+ Aggr_In_Place := Is_Delayed_Aggregate (Exp);
+ Delayed_Cond_Expr := Is_Delayed_Conditional_Expression (Exp);
+ Container_Aggr := Nkind (Exp) = N_Aggregate
+ and then Has_Aspect (T, Aspect_Aggregate);
-- An allocator with a container aggregate as qualified expression must
-- be rewritten into the form expected by Expand_Container_Aggregate.
if Container_Aggr then
Temp := Make_Temporary (Loc, 'P', N);
- Temp_Decl :=
+ Set_Analyzed (Exp, False);
+ Insert_Action (N,
Make_Object_Declaration (Loc,
Defining_Identifier => Temp,
Object_Definition => New_Occurrence_Of (PtrT, Loc),
- Expression => Relocate_Node (N));
-
- Set_Analyzed (Exp, False);
- Insert_Action (N, Temp_Decl);
- Rewrite (N, New_Occurrence_Of (Temp, Loc));
- Analyze_And_Resolve (N, PtrT);
- Apply_Predicate_Check (N, T, Deref => True);
+ Expression => Relocate_Node (N)));
-- Case of tagged type or type requiring finalization
@@ -812,21 +825,11 @@ package body Exp_Ch4 is
return;
end if;
- -- Actions inserted before:
- -- Temp : constant PtrT := new T'(Expression);
- -- Temp._tag = T'tag; -- when not class-wide
- -- [Deep_]Adjust (Temp.all);
-
- -- We analyze by hand the new internal allocator to avoid any
- -- recursion and inappropriate call to Initialize.
-
- Temp := Make_Temporary (Loc, 'P', N);
-
-- For a class wide allocation generate the following code:
-- type Equiv_Record is record ... end record;
-- implicit subtype CW is <Class_Wide_Subytpe>;
- -- temp : PtrT := new CW'(CW!(expr));
+ -- Temp : PtrT := new CW'(CW!(expr));
if Is_Class_Wide_Type (T) then
Expand_Subtype_From_Expr (Empty, T, Indic, Exp);
@@ -859,6 +862,16 @@ package body Exp_Ch4 is
Analyze_And_Resolve (Expression (N), Entity (Indic));
end if;
+ -- Actions inserted before:
+ -- Temp : constant PtrT := new T'(Expression);
+ -- Temp._tag = T'tag; -- when not class-wide
+ -- [Deep_]Adjust (Temp.all);
+
+ -- We analyze by hand the new internal allocator to avoid any
+ -- recursion and inappropriate call to Initialize.
+
+ Temp := Make_Temporary (Loc, 'P', N);
+
-- Processing for allocators returning non-interface types
if not Is_Interface (DesigT) then
@@ -869,17 +882,7 @@ package body Exp_Ch4 is
Build_Explicit_Assignment (Temp, PtrT);
else
- Node := Relocate_Node (N);
- Set_Analyzed (Node);
-
- Temp_Decl :=
- Make_Object_Declaration (Loc,
- Defining_Identifier => Temp,
- Constant_Present => True,
- Object_Definition => New_Occurrence_Of (PtrT, Loc),
- Expression => Node);
-
- Insert_Action (N, Temp_Decl);
+ Build_Simple_Allocation (Temp, PtrT);
end if;
-- Ada 2005 (AI-251): Handle allocators whose designated type is an
@@ -888,11 +891,11 @@ package body Exp_Ch4 is
else
declare
- Def_Id : constant Entity_Id := Make_Temporary (Loc, 'T');
- New_Decl : Node_Id;
+ Def_Id : constant Entity_Id := Make_Temporary (Loc, 'T', N);
+ New_Temp : constant Entity_Id := Make_Temporary (Loc, 'P', N);
begin
- New_Decl :=
+ Insert_Action (N,
Make_Full_Type_Declaration (Loc,
Defining_Identifier => Def_Id,
Type_Definition =>
@@ -900,11 +903,9 @@ package body Exp_Ch4 is
All_Present => True,
Null_Exclusion_Present => False,
Constant_Present =>
- Is_Access_Constant (Etype (N)),
+ Is_Access_Constant (PtrT),
Subtype_Indication =>
- New_Occurrence_Of (Etype (Exp), Loc)));
-
- Insert_Action (N, New_Decl);
+ New_Occurrence_Of (Etype (Exp), Loc))));
-- Inherit the allocation-related attributes from the original
-- access type.
@@ -918,23 +919,13 @@ package body Exp_Ch4 is
-- Declare the object using the previous type declaration
if Aggr_In_Place then
- Build_Aggregate_In_Place (Temp, Def_Id);
+ Build_Aggregate_In_Place (New_Temp, Def_Id);
elsif Delayed_Cond_Expr then
- Build_Explicit_Assignment (Temp, Def_Id);
+ Build_Explicit_Assignment (New_Temp, Def_Id);
else
- Node := Relocate_Node (N);
- Set_Analyzed (Node);
-
- Temp_Decl :=
- Make_Object_Declaration (Loc,
- Defining_Identifier => Temp,
- Constant_Present => True,
- Object_Definition => New_Occurrence_Of (Def_Id, Loc),
- Expression => Node);
-
- Insert_Action (N, Temp_Decl);
+ Build_Simple_Allocation (New_Temp, Def_Id);
end if;
-- Generate an additional object containing the address of the
@@ -944,18 +935,13 @@ package body Exp_Ch4 is
-- this pointer to reference the component associated with the
-- interface type will be done at the end of common processing.
- New_Decl :=
+ Insert_Action (N,
Make_Object_Declaration (Loc,
- Defining_Identifier => Make_Temporary (Loc, 'P'),
+ Defining_Identifier => Temp,
Object_Definition => New_Occurrence_Of (PtrT, Loc),
Expression =>
Unchecked_Convert_To (PtrT,
- New_Occurrence_Of (Temp, Loc)));
-
- Insert_Action (N, New_Decl);
-
- Temp_Decl := New_Decl;
- Temp := Defining_Identifier (New_Decl);
+ New_Occurrence_Of (New_Temp, Loc))));
end;
end if;
@@ -970,9 +956,8 @@ package body Exp_Ch4 is
-- Ada 2005 (AI-251): Suppress the tag assignment with class-wide
-- interface objects because in this case the tag does not change.
- elsif Is_Interface (Directly_Designated_Type (Etype (N))) then
- pragma Assert (Is_Class_Wide_Type
- (Directly_Designated_Type (Etype (N))));
+ elsif Is_Interface (DesigT) then
+ pragma Assert (Is_Class_Wide_Type (DesigT));
null;
-- Likewise if the allocator is made for a special return object
@@ -1022,21 +1007,23 @@ package body Exp_Ch4 is
and then Nkind (Exp) /= N_Function_Call
and then not Special_Return
then
- -- An unchecked conversion is needed in the classwide case because
- -- the designated type can be an ancestor of the subtype mark of
- -- the allocator.
-
- Adj_Call :=
- Make_Adjust_Call
- (Obj_Ref =>
- Unchecked_Convert_To (T,
- Make_Explicit_Dereference (Loc,
- Prefix => New_Occurrence_Of (Temp, Loc))),
- Typ => T);
-
- if Present (Adj_Call) then
- Insert_Action (N, Adj_Call);
- end if;
+ declare
+ Adj_Call : constant Node_Id :=
+ Make_Adjust_Call
+ (Obj_Ref =>
+ Unchecked_Convert_To (T,
+ Make_Explicit_Dereference (Loc,
+ Prefix => New_Occurrence_Of (Temp, Loc))),
+ Typ => T);
+ -- An unchecked conversion is needed in the CW case because
+ -- the designated type can be an ancestor of the subtype mark
+ -- of the allocator.
+
+ begin
+ if Present (Adj_Call) then
+ Insert_Action (N, Adj_Call);
+ end if;
+ end;
end if;
-- This needs to done before generating the accessibility check below
@@ -1051,30 +1038,12 @@ package body Exp_Ch4 is
Apply_Accessibility_Check_For_Allocator (N, Exp, Temp);
- Rewrite (N, New_Occurrence_Of (Temp, Loc));
- Analyze_And_Resolve (N, PtrT);
-
- if Aggr_In_Place or else Delayed_Cond_Expr then
- Apply_Predicate_Check (N, T, Deref => True);
- end if;
-
- -- Ada 2005 (AI-251): Displace the pointer to reference the record
- -- component containing the secondary dispatch table of the interface
- -- type.
-
- if Is_Interface (DesigT) then
- Displace_Allocator_Pointer (N);
- end if;
-
-- Case of aggregate built in place
elsif Aggr_In_Place then
Temp := Make_Temporary (Loc, 'P', N);
Build_Aggregate_In_Place (Temp, PtrT);
Build_Allocate_Deallocate_Proc (Declaration_Node (Temp), Mark => N);
- Rewrite (N, New_Occurrence_Of (Temp, Loc));
- Analyze_And_Resolve (N, PtrT);
- Apply_Predicate_Check (N, T, Deref => True);
-- If the initialization expression is a conditional expression whose
-- expansion has been delayed, assign it explicitly to the allocator,
@@ -1084,13 +1053,19 @@ package body Exp_Ch4 is
Temp := Make_Temporary (Loc, 'P', N);
Build_Explicit_Assignment (Temp, PtrT);
Build_Allocate_Deallocate_Proc (Declaration_Node (Temp), Mark => N);
- Rewrite (N, New_Occurrence_Of (Temp, Loc));
- Analyze_And_Resolve (N, PtrT);
- Apply_Predicate_Check (N, T, Deref => True);
-- Default case
else
+ -- Ada 2005 (AI-318-02): If the initialization expression is a call
+ -- to a build-in-place function, then access to the allocated object
+ -- must be passed to the function.
+
+ if Is_Build_In_Place_Function_Call (Exp) then
+ Make_Build_In_Place_Call_In_Allocator (N, Exp);
+ return;
+ end if;
+
if Is_Access_Type (T) and then Can_Never_Be_Null (T) then
Install_Null_Excluding_Check (Exp);
end if;
@@ -1111,8 +1086,6 @@ package body Exp_Ch4 is
end if;
end if;
- Build_Allocate_Deallocate_Proc (N);
-
-- For an access-to-unconstrained-packed-array type, build an
-- expression with a constrained subtype in order for the code
-- generator to compute the proper size for the allocator.
@@ -1132,13 +1105,37 @@ package body Exp_Ch4 is
end;
end if;
- -- Ada 2005 (AI-318-02): If the initialization expression is a call
- -- to a build-in-place function, then access to the allocated object
- -- must be passed to the function.
+ -- ??? If the allocator is present inside a record type, then the
+ -- actions are attached to the current scope, to be inserted and
+ -- analyzed on exit from the scope, so we cannot do any rewriting.
- if Is_Build_In_Place_Function_Call (Exp) then
- Make_Build_In_Place_Call_In_Allocator (N, Exp);
+ if Is_Record_Type (Current_Scope)
+ and then not Is_Frozen (Current_Scope)
+ then
+ Build_Allocate_Deallocate_Proc (N);
+ return;
end if;
+
+ Temp := Make_Temporary (Loc, 'P', N);
+ Build_Simple_Allocation (Temp, PtrT);
+ Build_Allocate_Deallocate_Proc (Declaration_Node (Temp), Mark => N);
+ end if;
+
+ Rewrite (N, New_Occurrence_Of (Temp, Loc));
+ Preserve_Comes_From_Source (N, Original_Node (N));
+ Analyze_And_Resolve (N, PtrT);
+
+ Apply_Predicate_Check (N, T, Deref => True);
+ if not Static_Match then
+ Apply_Predicate_Check (N, DesigT, Deref => True);
+ end if;
+
+ -- Ada 2005 (AI-251): Displace the pointer to reference the record
+ -- component containing the secondary dispatch table of the interface
+ -- type.
+
+ if Is_Interface (DesigT) then
+ Displace_Allocator_Pointer (N);
end if;
exception
diff --git a/gcc/ada/sem_ch4.adb b/gcc/ada/sem_ch4.adb
index 68e0eb9b10d7..70abf7ccc7de 100644
--- a/gcc/ada/sem_ch4.adb
+++ b/gcc/ada/sem_ch4.adb
@@ -731,14 +731,14 @@ package body Sem_Ch4 is
Check_Fully_Declared (Type_Id, N);
-- Ada 2005 (AI-231): If the designated type is itself an access
- -- type that excludes null, its default initialization will
- -- be a null object, and we can insert an unconditional raise
+ -- type that excludes null, its default initialization (if any)
+ -- will be a null object and we can insert an unconditional raise
-- before the allocator.
-- Ada 2012 (AI-104): A not null indication here is altogether
-- illegal.
- if Can_Never_Be_Null (Type_Id) then
+ if Can_Never_Be_Null (Type_Id) and then not No_Initialization (N) then
if Expander_Active then
Apply_Compile_Time_Constraint_Error
(N, "null value not allowed here??", CE_Null_Not_Allowed);
