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sem_util.ads (Indexed_Component_Bit_Offset): Declare. 

2016-06-16  Eric Botcazou  <ebotcazou@adacore.com>

	* sem_util.ads (Indexed_Component_Bit_Offset): Declare.
	* sem_util.adb (Indexed_Component_Bit_Offset): New
	function returning the offset of an indexed component.
	(Has_Compatible_Alignment_Internal): Call it.
	* sem_ch13.adb (Offset_Value): New function returning the offset of an
	Address attribute reference from the underlying entity.
	(Validate_Address_Clauses): Call it and take the offset into
	account for the size warning.

From-SVN: r237511
This commit is contained in:
Eric Botcazou 2016-06-16 10:19:51 +00:00 committed by Arnaud Charlet
parent 3455747810
commit 36d3d5d3db
4 changed files with 139 additions and 17 deletions
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11
gcc/ada/ChangeLog
View File

@ -1,3 +1,14 @@
2016-06-16 Eric Botcazou <ebotcazou@adacore.com>
* sem_util.ads (Indexed_Component_Bit_Offset): Declare.
* sem_util.adb (Indexed_Component_Bit_Offset): New
function returning the offset of an indexed component.
(Has_Compatible_Alignment_Internal): Call it.
* sem_ch13.adb (Offset_Value): New function returning the offset of an
Address attribute reference from the underlying entity.
(Validate_Address_Clauses): Call it and take the offset into
account for the size warning.
2016-06-16 Hristian Kirtchev <kirtchev@adacore.com>
* bindgen.adb, exp_util.adb, sem_ch9.adb, sem_util.adb: Minor

67
gcc/ada/sem_ch13.adb
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@ -13626,6 +13626,53 @@ package body Sem_Ch13 is
------------------------------
procedure Validate_Address_Clauses is
function Offset_Value (Expr : Node_Id) return Uint;
-- Given an Address attribute reference, return the value in bits of its
-- offset from the first bit of the underlying entity, or 0 if it is not
-- known at compile time.
------------------
-- Offset_Value --
------------------
function Offset_Value (Expr : Node_Id) return Uint is
N : Node_Id := Prefix (Expr);
Off : Uint;
Val : Uint := Uint_0;
begin
-- Climb the prefix chain and compute the cumulative offset
loop
if Is_Entity_Name (N) then
return Val;
elsif Nkind (N) = N_Selected_Component then
Off := Component_Bit_Offset (Entity (Selector_Name (N)));
if Off /= No_Uint and then Off >= Uint_0 then
Val := Val + Off;
N := Prefix (N);
else
return Uint_0;
end if;
elsif Nkind (N) = N_Indexed_Component then
Off := Indexed_Component_Bit_Offset (N);
if Off /= No_Uint then
Val := Val + Off;
N := Prefix (N);
else
return Uint_0;
end if;
else
return Uint_0;
end if;
end loop;
end Offset_Value;
-- Start of processing for Validate_Address_Clauses
begin
for J in Address_Clause_Checks.First .. Address_Clause_Checks.Last loop
declare
@ -13640,6 +13687,8 @@ package body Sem_Ch13 is
X_Size : Uint;
Y_Size : Uint;
X_Offs : Uint;
begin
-- Skip processing of this entry if warning already posted
@ -13651,16 +13700,25 @@ package body Sem_Ch13 is
X_Alignment := Alignment (ACCR.X);
Y_Alignment := Alignment (ACCR.Y);
-- Similarly obtain sizes
-- Similarly obtain sizes and offset
X_Size := Esize (ACCR.X);
Y_Size := Esize (ACCR.Y);
if ACCR.Off
and then Nkind (Expr) = N_Attribute_Reference
and then Attribute_Name (Expr) = Name_Address
then
X_Offs := Offset_Value (Expr);
else
X_Offs := Uint_0;
end if;
-- Check for large object overlaying smaller one
if Y_Size > Uint_0
and then X_Size > Uint_0
and then X_Size > Y_Size
and then X_Offs + X_Size > Y_Size
then
Error_Msg_NE ("??& overlays smaller object", ACCR.N, ACCR.X);
Error_Msg_N
@ -13672,6 +13730,11 @@ package body Sem_Ch13 is
Error_Msg_Uint_1 := Y_Size;
Error_Msg_NE ("\??size of & is ^", ACCR.N, ACCR.Y);
if X_Offs /= Uint_0 then
Error_Msg_Uint_1 := X_Offs;
Error_Msg_NE ("\??and offset of & is ^", ACCR.N, ACCR.X);
end if;
-- Check for inadequate alignment, both of the base object
-- and of the offset, if any. We only do this check if the
-- run-time Alignment_Check is active. No point in warning

72
gcc/ada/sem_util.adb
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@ -8780,7 +8780,6 @@ package body Sem_Util is
elsif Nkind (Expr) = N_Indexed_Component then
declare
Typ : constant Entity_Id := Etype (Prefix (Expr));
Ind : constant Node_Id := First_Index (Typ);
begin
-- Packing generates unknown alignment if layout is not done
@ -8789,22 +8788,12 @@ package body Sem_Util is
Set_Result (Unknown);
end if;
-- Check prefix and component offset
-- Check prefix and component offset (or at least size)
Check_Prefix;
Offs := Component_Size (Typ);
-- Small optimization: compute the full offset when possible
if Offs /= No_Uint
and then Offs > Uint_0
and then Present (Ind)
and then Nkind (Ind) = N_Range
and then Compile_Time_Known_Value (Low_Bound (Ind))
and then Compile_Time_Known_Value (First (Expressions (Expr)))
then
Offs := Offs * (Expr_Value (First (Expressions (Expr)))
- Expr_Value (Low_Bound ((Ind))));
Offs := Indexed_Component_Bit_Offset (Expr);
if Offs = No_Uint then
Offs := Component_Size (Typ);
end if;
end;
end if;
@ -11064,6 +11053,59 @@ package body Sem_Util is
return Empty;
end Incomplete_Or_Partial_View;
----------------------------------
-- Indexed_Component_Bit_Offset --
----------------------------------
function Indexed_Component_Bit_Offset (N : Node_Id) return Uint is
Exp : constant Node_Id := First (Expressions (N));
Typ : constant Entity_Id := Etype (Prefix (N));
Off : constant Uint := Component_Size (Typ);
Ind : Node_Id;
begin
-- Return early if the component size is not known or variable
if Off = No_Uint or else Off < Uint_0 then
return No_Uint;
end if;
-- Deal with the degenerate case of an empty component
if Off = Uint_0 then
return Off;
end if;
-- Check that both the index value and the low bound are known
if not Compile_Time_Known_Value (Exp) then
return No_Uint;
end if;
Ind := First_Index (Typ);
if No (Ind) then
return No_Uint;
end if;
if Nkind (Ind) = N_Subtype_Indication then
Ind := Constraint (Ind);
if Nkind (Ind) = N_Range_Constraint then
Ind := Range_Expression (Ind);
end if;
end if;
if Nkind (Ind) /= N_Range
or else not Compile_Time_Known_Value (Low_Bound (Ind))
then
return No_Uint;
end if;
-- Return the scaled offset
return Off * (Expr_Value (Exp) - Expr_Value (Low_Bound ((Ind))));
end Indexed_Component_Bit_Offset;
-----------------------------------------
-- Inherit_Default_Init_Cond_Procedure --
-----------------------------------------

6
gcc/ada/sem_util.ads
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@ -1232,6 +1232,12 @@ package Sem_Util is
-- partial view of the same entity. Note that Id may not have a partial
-- view in which case the function returns Empty.
function Indexed_Component_Bit_Offset (N : Node_Id) return Uint;
-- Given an N_Indexed_Component node, return the first bit position of the
-- component if it is known at compile time. A value of No_Uint means that
-- either the value is not yet known before back-end processing or it is
-- not known at compile time after back-end processing.
procedure Inherit_Default_Init_Cond_Procedure (Typ : Entity_Id);
-- Inherit the default initial condition procedure from the parent type of
-- derived type Typ.