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Guarded allocator: Ensure alignment and size of MemHead

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Ensure that the MemHead and MemHeadAligned are such that memory
allocation followed with the head offset keeps the allocation
aligned to at least MEM_MIN_CPP_ALIGNMENT.

Pull Request: https://projects.blender.org/blender/blender/pulls/120582
This commit is contained in:
Sergey Sharybin
2024-04-12 17:22:46 +02:00
committed by Sergey Sharybin
parent fac451e513
commit a4b36cd0d5
3 changed files with 13 additions and 0 deletions
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7
intern/guardedalloc/MEM_guardedalloc.h
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@@ -258,6 +258,13 @@ void MEM_use_guarded_allocator(void);
# include <type_traits>
# include <utility>
/* Conservative value of memory alignment returned by non-aligned OS-level memory allocation
* functions. For alignments smaller than this value, using non-aligned versions of allocator API
* functions is okay, allowing use of calloc, for example. */
# define MEM_MIN_CPP_ALIGNMENT \
(__STDCPP_DEFAULT_NEW_ALIGNMENT__ < alignof(void *) ? __STDCPP_DEFAULT_NEW_ALIGNMENT__ : \
alignof(void *))
/**
* Allocate new memory for and constructs an object of type #T.
* #MEM_delete should be used to delete the object. Just calling #MEM_freeN is not enough when #T

2
intern/guardedalloc/intern/mallocn_guarded_impl.cc
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@@ -129,6 +129,8 @@ typedef struct MemHead {
#endif
} MemHead;
static_assert(MEM_MIN_CPP_ALIGNMENT <= alignof(MemHead), "Bad alignment of MemHead");
static_assert(MEM_MIN_CPP_ALIGNMENT <= sizeof(MemHead), "Bad size of MemHead");
typedef MemHead MemHeadAligned;

4
intern/guardedalloc/intern/mallocn_lockfree_impl.cc
View File

@@ -32,11 +32,15 @@ typedef struct MemHead {
/* Length of allocated memory block. */
size_t len;
} MemHead;
static_assert(MEM_MIN_CPP_ALIGNMENT <= alignof(MemHead), "Bad alignment of MemHead");
static_assert(MEM_MIN_CPP_ALIGNMENT <= sizeof(MemHead), "Bad size of MemHead");
typedef struct MemHeadAligned {
short alignment;
size_t len;
} MemHeadAligned;
static_assert(MEM_MIN_CPP_ALIGNMENT <= alignof(MemHeadAligned), "Bad alignment of MemHeadAligned");
static_assert(MEM_MIN_CPP_ALIGNMENT <= sizeof(MemHeadAligned), "Bad size of MemHeadAligned");
static bool malloc_debug_memset = false;