From: Javier Miranda <mira...@adacore.com>
When the type imposed by the context for an interpolated string is
constrained, the compiler silently omits adding a runtime check.
gcc/ada/ChangeLog:
* exp_ch2.adb (Expand_N_Interpolated_String_Literal): Use the
base type of the type imposed by the context for building the
interpolated string image; required to allow the expander adding
the missing runtime check when the target type is constrained.
(Apply_Static_Length_Check): New subprogram.
Tested on x86_64-pc-linux-gnu, committed on master.
---
gcc/ada/exp_ch2.adb | 72 +++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 69 insertions(+), 3 deletions(-)
diff --git a/gcc/ada/exp_ch2.adb b/gcc/ada/exp_ch2.adb
index 99a16947525..aacf26c5128 100644
--- a/gcc/ada/exp_ch2.adb
+++ b/gcc/ada/exp_ch2.adb
@@ -51,7 +51,9 @@ with Sinfo.Utils; use Sinfo.Utils;
with Sinput; use Sinput;
with Snames; use Snames;
with Stand;
+with Stringt; use Stringt;
with Tbuild; use Tbuild;
+with Uintp; use Uintp;
package body Exp_Ch2 is
@@ -721,6 +723,12 @@ package body Exp_Ch2 is
procedure Expand_N_Interpolated_String_Literal (N : Node_Id) is
+ procedure Apply_Static_Length_Check (Typ : Entity_Id);
+ -- Tries to determine statically whether the length of the interpolated
+ -- string N exceeds the length of the target subtype Typ. If it can be
+ -- determined at compile time then an N_Raise_Constraint_Error node
+ -- replaces the interpolated string N, and a warning message is issued.
+
function Build_Interpolated_String_Image (N : Node_Id) return Node_Id;
-- Build the following Expression_With_Actions node:
-- do
@@ -733,6 +741,47 @@ package body Exp_Ch2 is
-- Destroy (Sink);
-- in Result end
+ -------------------------------
+ -- Apply_Static_Length_Check --
+ -------------------------------
+
+ procedure Apply_Static_Length_Check (Typ : Entity_Id) is
+ HB : constant Node_Id := High_Bound (First_Index (Typ));
+ LB : constant Node_Id := Low_Bound (First_Index (Typ));
+ Str_Elem : Node_Id;
+ Str_Length : Nat;
+ Typ_Length : Nat;
+
+ begin
+ if Compile_Time_Known_Value (LB)
+ and then Compile_Time_Known_Value (HB)
+ then
+ Typ_Length := UI_To_Int (Expr_Value (HB) - Expr_Value (LB) + 1);
+
+ -- Compute the minimum length of the interpolated string: the
+ -- length of the concatenation of the string literals composing
+ -- the interpolated string.
+
+ Str_Length := 0;
+ Str_Elem := First (Expressions (N));
+ while Present (Str_Elem) loop
+ if Nkind (Str_Elem) = N_String_Literal then
+ Str_Length := Str_Length + String_Length (Strval (Str_Elem));
+ end if;
+
+ Next (Str_Elem);
+ end loop;
+
+ if Str_Length > Typ_Length then
+ Apply_Compile_Time_Constraint_Error
+ (N, "wrong length for interpolated string of}??",
+ CE_Length_Check_Failed,
+ Ent => Typ,
+ Typ => Typ);
+ end if;
+ end if;
+ end Apply_Static_Length_Check;
+
-------------------------------------
-- Build_Interpolated_String_Image --
-------------------------------------
@@ -747,10 +796,11 @@ package body Exp_Ch2 is
Object_Definition =>
New_Occurrence_Of (RTE (RE_Buffer_Type), Loc));
+ B_Type : constant Entity_Id := Base_Type (Etype (N));
Get_Id : constant RE_Id :=
- (if Etype (N) = Stand.Standard_String then
+ (if B_Type = Stand.Standard_String then
RE_Get
- elsif Etype (N) = Stand.Standard_Wide_String then
+ elsif B_Type = Stand.Standard_Wide_String then
RE_Wide_Get
else
RE_Wide_Wide_Get);
@@ -760,7 +810,7 @@ package body Exp_Ch2 is
Make_Object_Declaration (Loc,
Defining_Identifier => Result_Entity,
Object_Definition =>
- New_Occurrence_Of (Etype (N), Loc),
+ New_Occurrence_Of (B_Type, Loc),
Expression =>
Make_Function_Call (Loc,
Name => New_Occurrence_Of (RTE (Get_Id), Loc),
@@ -838,8 +888,24 @@ package body Exp_Ch2 is
-- Start of processing for Expand_N_Interpolated_String_Literal
begin
+ -- If the type imposed by the context is constrained then check that
+ -- the statically known length of the interpolated string does not
+ -- exceed the length of its type.
+
+ if Is_Constrained (Typ) then
+ Apply_Static_Length_Check (Typ);
+
+ if Nkind (N) = N_Raise_Constraint_Error then
+ return;
+ end if;
+ end if;
+
Rewrite (N, Build_Interpolated_String_Image (N));
Analyze_And_Resolve (N, Typ);
+
+ if Is_Constrained (Typ) then
+ Apply_Length_Check (Expression (N), Typ);
+ end if;
end Expand_N_Interpolated_String_Literal;
end Exp_Ch2;
--
2.43.0
