Commit cbbf8c8a2d77d84ce88ea1cef9a3e7d54081e33d | zig

author	Frank Denis <124872+jedisct1@users.noreply.github.com> 2023-01-12 14:48:14+01:00
committer	GitHub <noreply@github.com> 2023-01-12 13:48:14+00:00
log	cbbf8c8a2d77d84ce88ea1cef9a3e7d54081e33d
tree	dc5243974d7ffa4b2ea42ae5f3607a1f4965298e
parent	4b329176460d91056b75f0798778b1c58e0f104b
signature	Signed by PGP key 4AEE18F83AFDEB23

wasi-libc: use __heap_end if available (#14273)

The symbol was introduced in LLD 15.0.7, as a way to know how
much memory can be allocated:

https://github.com/llvm/llvm-project/commit/1095870e8ceddc5371f446f4e7c3473f89a461cd
https://github.com/WebAssembly/wasi-libc/pull/377

1 files changed, 5 insertions(+), 1 deletions(-)

lib
- libc
  - wasi
    emmalloc
    emmalloc.c

lib/libc/wasi/emmalloc/emmalloc.c+5-1

...	@@ -56,6 +56,7 @@	...	@@ -56,6 +56,7 @@
56		56
57	// Defind by the linker to have the address of the start of the heap.	57	// Defind by the linker to have the address of the start of the heap.
58	extern unsigned char __heap_base;	58	extern unsigned char __heap_base;
		59	extern unsigned char __heap_end __attribute__((__weak__));
59		60
60	// Behavior of right shifting a signed integer is compiler implementation defined.	61	// Behavior of right shifting a signed integer is compiler implementation defined.
61	static_assert((((int32_t)0x80000000U) >> 31) == -1, "This malloc implementation requires that right-shifting a signed integer produces a sign-extending (arithmetic) shift!");	62	static_assert((((int32_t)0x80000000U) >> 31) == -1, "This malloc implementation requires that right-shifting a signed integer produces a sign-extending (arithmetic) shift!");
...	@@ -545,7 +546,10 @@ static bool claim_more_memory(size_t numBytes)	...	@@ -545,7 +546,10 @@ static bool claim_more_memory(size_t numBytes)
545	// If this is the first time we're called, see if we can use	546	// If this is the first time we're called, see if we can use
546	// the initial heap memory set up by wasm-ld.	547	// the initial heap memory set up by wasm-ld.
547	if (!listOfAllRegions) {	548	if (!listOfAllRegions) {
548	unsigned char *heap_end = sbrk(0);	549	unsigned char *heap_end = &__heap_end;
		550	if (heap_end == NULL)
		551	heap_end = sbrk(0);
		552
549	if (numBytes <= (size_t)(heap_end - &__heap_base)) {	553	if (numBytes <= (size_t)(heap_end - &__heap_base)) {
550	startPtr = &__heap_base;	554	startPtr = &__heap_base;
551	endPtr = heap_end;	555	endPtr = heap_end;