MS CRT libraries (UCRT, msvcr70+ and os system msvcrt) for functions
_aligned_malloc() and _aligned_offset_malloc() allocate the source buffer
slightly smaller than the mingw-w64 functions in mingw-aligned-malloc.c.
This is because the alignment gap can be used for the user data too.
Do exactly same math calculation in the mingw-w64 implementation as is UCRT
doing. Same calculation is in msvcr70 and probably also in system msvcrt
library (at least different _msize() tests confirms it).
This will allow to call __mingw_aligned_msize() on buffer allocated by
MS CRT _aligned_malloc() function from msvcrt.dll, msvcr70.dll and
msvcrt71.dll CRT libraries. This is very useful because these CRT libraries
do not have _aligned_msize() function and hence mingw-w64 could emulate it
via __mingw_aligned_msize().
---
mingw-w64-crt/misc/mingw-aligned-malloc.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/mingw-w64-crt/misc/mingw-aligned-malloc.c
b/mingw-w64-crt/misc/mingw-aligned-malloc.c
index be07ed6bcfb1..02872c921a18 100644
--- a/mingw-w64-crt/misc/mingw-aligned-malloc.c
+++ b/mingw-w64-crt/misc/mingw-aligned-malloc.c
@@ -22,9 +22,10 @@
#define UI(p) ((uintptr_t) (p))
#define CP(p) ((char *) p)
+#define GAP(offset) ((0 - offset) & (sizeof (void *) -1))
#define PTR_ALIGN(p0, alignment, offset) \
- ((void *) (((UI(p0) + (alignment + sizeof(void*)) + offset)
\
- & (~UI(alignment - 1))) \
+ ((void *) (((UI(p0) + (alignment + GAP(offset) + sizeof(void*)) +
offset) \
+ & (~UI(alignment))) \
- offset))
/* Pointer must sometimes be aligned; assume sizeof(void*) is a power of two.
*/
@@ -44,12 +45,13 @@ __mingw_aligned_offset_malloc (size_t size, size_t
alignment, size_t offset)
return ((void *) 0);
if (alignment < sizeof (void *))
alignment = sizeof (void *);
+ alignment--;
/* Including the extra sizeof(void*) is overkill on a 32-bit
machine, since malloc is already 8-byte aligned, as long
as we enforce alignment >= 8 ...but oh well. */
- p0 = malloc (size + (alignment + sizeof (void *)));
+ p0 = malloc (size + (alignment + GAP (offset) + sizeof (void *)));
if (!p0)
return ((void *) 0);
p = PTR_ALIGN (p0, alignment, offset);
@@ -88,6 +90,7 @@ __mingw_aligned_offset_realloc (void *memblock, size_t size,
}
if (alignment < sizeof (void *))
alignment = sizeof (void *);
+ alignment--;
p0 = ORIG_PTR (memblock);
/* It is an error for the alignment to change. */
@@ -95,7 +98,7 @@ __mingw_aligned_offset_realloc (void *memblock, size_t size,
goto bad;
shift = CP (memblock) - CP (p0);
- p0 = realloc (p0, size + (alignment + sizeof (void *)));
+ p0 = realloc (p0, size + (alignment + GAP (offset) + sizeof (void *)));
if (!p0)
return ((void *) 0);
p = PTR_ALIGN (p0, alignment, offset);
@@ -131,6 +134,7 @@ __mingw_aligned_msize (void *memblock, size_t alignment,
size_t offset)
}
if (alignment < sizeof (void *))
alignment = sizeof (void *);
+ alignment--;
p0 = ORIG_PTR (memblock);
@@ -141,5 +145,5 @@ __mingw_aligned_msize (void *memblock, size_t alignment,
size_t offset)
return (size_t)-1;
}
- return _msize (p0) - (alignment + sizeof (void *));
+ return _msize (p0) - (alignment + GAP (offset) + sizeof (void *));
}
--
2.20.1
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