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Replaced SDL_SIMDAlloc(), SDL_SIMDRealloc(), and SDL_SIMDFree() with SDL_aligned_alloc() and SDL_aligned_free()

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Fixes https://github.com/libsdl-org/SDL/issues/5641
This commit is contained in:
Sam Lantinga
2023-01-09 17:42:16 -08:00
parent 9597c482fa
commit 2aa9569b3e
13 changed files with 132 additions and 194 deletions
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87
src/cpuinfo/SDL_cpuinfo.c
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@@ -139,7 +139,7 @@ static int CPU_haveCPUID(void)
: "%eax", "%ecx"
);
#elif (defined(__GNUC__) || defined(__llvm__)) && defined(__x86_64__)
/* Technically, if this is being compiled under __x86_64__ then it has
/* Technically, if this is being compiled under __x86_64__ then it has
CPUid by definition. But it's nice to be able to prove it. :) */
__asm__ (
" pushfq # Get original EFLAGS \n"
@@ -1094,91 +1094,6 @@ SDL_SIMDGetAlignment(void)
return SDL_SIMDAlignment;
}
void *
SDL_SIMDAlloc(const size_t len)
{
const size_t alignment = SDL_SIMDGetAlignment();
const size_t padding = (alignment - (len % alignment)) % alignment;
Uint8 *retval = NULL;
Uint8 *ptr;
size_t to_allocate;
/* alignment + padding + sizeof (void *) is bounded (a few hundred
* bytes max), so no need to check for overflow within that argument */
if (SDL_size_add_overflow(len, alignment + padding + sizeof(void *), &to_allocate)) {
return NULL;
}
ptr = (Uint8 *)SDL_malloc(to_allocate);
if (ptr) {
/* store the actual allocated pointer right before our aligned pointer. */
retval = ptr + sizeof(void *);
retval += alignment - (((size_t)retval) % alignment);
*(((void **)retval) - 1) = ptr;
}
return retval;
}
void *
SDL_SIMDRealloc(void *mem, const size_t len)
{
const size_t alignment = SDL_SIMDGetAlignment();
const size_t padding = (alignment - (len % alignment)) % alignment;
Uint8 *retval = (Uint8 *)mem;
void *oldmem = mem;
size_t memdiff = 0, ptrdiff;
Uint8 *ptr;
size_t to_allocate;
/* alignment + padding + sizeof (void *) is bounded (a few hundred
* bytes max), so no need to check for overflow within that argument */
if (SDL_size_add_overflow(len, alignment + padding + sizeof(void *), &to_allocate)) {
return NULL;
}
if (mem) {
mem = *(((void **)mem) - 1);
/* Check the delta between the real pointer and user pointer */
memdiff = ((size_t)oldmem) - ((size_t)mem);
}
ptr = (Uint8 *)SDL_realloc(mem, to_allocate);
if (ptr == NULL) {
return NULL; /* Out of memory, bail! */
}
/* Store the actual allocated pointer right before our aligned pointer. */
retval = ptr + sizeof(void *);
retval += alignment - (((size_t)retval) % alignment);
/* Make sure the delta is the same! */
if (mem) {
ptrdiff = ((size_t)retval) - ((size_t)ptr);
if (memdiff != ptrdiff) { /* Delta has changed, copy to new offset! */
oldmem = (void *)(((uintptr_t)ptr) + memdiff);
/* Even though the data past the old `len` is undefined, this is the
* only length value we have, and it guarantees that we copy all the
* previous memory anyhow.
*/
SDL_memmove(retval, oldmem, len);
}
}
/* Actually store the allocated pointer, finally. */
*(((void **)retval) - 1) = ptr;
return retval;
}
void SDL_SIMDFree(void *ptr)
{
if (ptr) {
SDL_free(*(((void **)ptr) - 1));
}
}
#ifdef TEST_MAIN
#include <stdio.h>