https://gcc.gnu.org/g:d8610fb01b7a380acdd5872f4eb080599643f903
commit r16-1145-gd8610fb01b7a380acdd5872f4eb080599643f903
Author: Ronan Desplanques <desplanq...@adacore.com>
Date: Mon Jan 20 13:37:08 2025 +0100
ada: Fix unnecessarily large allocation in New_String
This patches fixes an issue where Interfaces.C.Strings.New_String
allocates more memory than necessary when passed a string that contains
a NUL character.
gcc/ada/ChangeLog:
* libgnat/i-cstrin.adb (New_String): Fix size of allocation.
Diff:
---
gcc/ada/libgnat/i-cstrin.adb | 35 ++++++++++++++++++++++++-----------
1 file changed, 24 insertions(+), 11 deletions(-)
diff --git a/gcc/ada/libgnat/i-cstrin.adb b/gcc/ada/libgnat/i-cstrin.adb
index 6d329254aff3..974ba3a0e8ca 100644
--- a/gcc/ada/libgnat/i-cstrin.adb
+++ b/gcc/ada/libgnat/i-cstrin.adb
@@ -153,20 +153,33 @@ is
-- the result, and doesn't copy the string on the stack, otherwise its
-- use is limited when used from tasks on large strings.
- Result : constant chars_ptr := Memory_Alloc (Str'Length + 1);
+ Len : Natural := 0;
+ -- Length of the longest prefix of Str that doesn't contain NUL
- Result_Array : char_array (1 .. Str'Length + 1);
- for Result_Array'Address use To_Address (Result);
- pragma Import (Ada, Result_Array);
+ Result : chars_ptr;
+ begin
+ for C of Str loop
+ if C = ASCII.NUL then
+ exit;
+ end if;
+ Len := Len + 1;
+ end loop;
- Count : size_t;
+ Result := Memory_Alloc (size_t (Len) + 1);
+
+ declare
+ Result_Array : char_array (1 .. size_t (Len) + 1)
+ with Address => To_Address (Result), Import, Convention => Ada;
+
+ Count : size_t;
+ begin
+ To_C
+ (Item => Str (Str'First .. Str'First + Len - 1),
+ Target => Result_Array,
+ Count => Count,
+ Append_Nul => True);
+ end;
- begin
- To_C
- (Item => Str,
- Target => Result_Array,
- Count => Count,
- Append_Nul => True);
return Result;
end New_String;
