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Assert on proper alignment in dlmalloc #14634

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Merged
merged 5 commits into from
Jul 12, 2021
Merged

Assert on proper alignment in dlmalloc #14634

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7d60057
[ci skip]
kripken Jul 7, 2021
aee56e9
Merge remote-tracking branch 'origin/main' into align
kripken Jul 12, 2021
797f670
fix
kripken Jul 12, 2021
9a760b0
emmalloc too
kripken Jul 12, 2021
1cf6528
feedback
kripken Jul 12, 2021
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11 changes: 11 additions & 0 deletions system/lib/dlmalloc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -24,8 +24,19 @@
#define USE_SPIN_LOCKS 0 // Ensure we use pthread_mutex_t.
#endif

#ifndef MALLOC_ALIGNMENT
#include <stddef.h>
/* `malloc`ed pointers must be aligned at least as strictly as max_align_t. */
#define MALLOC_ALIGNMENT (__alignof__(max_align_t))
/*
Emscripten aligns even float128 to 64-bits, to save size and increase speed.
See https://github.com/emscripten-core/emscripten/issues/10072
*/
_Static_assert(MALLOC_ALIGNMENT == 8, "max_align_t must be 8");
#endif

#endif // __EMSCRIPTEN__
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@sbc100 sbc100 Jul 12, 2021

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This same code should be used in emmalloc too?



#define __THROW
#define __attribute_malloc__
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4 changes: 3 additions & 1 deletion system/lib/emmalloc.cpp
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Expand Up @@ -39,6 +39,7 @@
* malloc.
*/

#include <stddef.h>
#include <stdint.h>
#include <unistd.h>
#include <memory.h>
Expand All @@ -60,7 +61,8 @@ extern "C"

// Configuration: specifies the minimum alignment that malloc()ed memory outputs. Allocation requests with smaller alignment
// than this will yield an allocation with this much alignment.
#define MALLOC_ALIGNMENT 8
#define MALLOC_ALIGNMENT alignof(max_align_t)
_Static_assert(alignof(max_align_t) == 8, "max_align_t must be correct");

#define EMMALLOC_EXPORT __attribute__((weak, __visibility__("default")))

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