diff options
Diffstat (limited to 'dlmalloc/src/malloc.c')
| -rw-r--r-- | dlmalloc/src/malloc.c | 37 |
1 files changed, 16 insertions, 21 deletions
diff --git a/dlmalloc/src/malloc.c b/dlmalloc/src/malloc.c index c9c8ea6..9fdfd8f 100644 --- a/dlmalloc/src/malloc.c +++ b/dlmalloc/src/malloc.c @@ -4593,14 +4593,14 @@ void* dlmalloc(size_t bytes) { ensure_initialization(); /* initialize in sys_alloc if not using locks */ #endif + if (!PREACTION(gm)) { #if __wasilibc_unmodified_upstream // Try to initialize the allocator. #else - if (!is_initialized(gm)) { - try_init_allocator(); - } + if (!is_initialized(gm)) { + try_init_allocator(); + } #endif - if (!PREACTION(gm)) { void* mem; size_t nb; if (bytes <= MAX_SMALL_REQUEST) { @@ -5215,7 +5215,7 @@ static void internal_inspect_all(mstate m, /* Symbol marking the end of data, bss and explicit stack, provided by wasm-ld. */ extern char __heap_base; -extern char __heap_end __attribute__((__weak__)); +extern char __heap_end; /* Initialize the initial state of dlmalloc to be able to use free memory between __heap_base and initial. */ static void try_init_allocator(void) { @@ -5227,23 +5227,18 @@ static void try_init_allocator(void) { char *base = &__heap_base; // Try to use the linker pseudo-symbol `__heap_end` for the initial size of - // the heap, but if that's not defined due to LLVM being too old perhaps then - // round up `base` to the nearest `PAGESIZE`. The initial size of linear - // memory will be at least the heap base to this page boundary, and it's then - // assumed that the initial linear memory image was truncated at that point. - // While this reflects the default behavior of `wasm-ld` it is also possible - // for users to craft larger linear memories by passing options to extend - // beyond this threshold. In this situation the memory will not be used for - // dlmalloc. - // - // Note that `sbrk(0)`, or in dlmalloc-ese `CALL_MORECORE(0)`, is specifically - // not used here. That captures the current size of the heap but is only - // correct if the we're the first to try to grow the heap. If the heap has - // grown elsewhere, such as a different allocator in place, then this would - // incorrectly claim such memroy as our own. + // the heap. char *end = &__heap_end; - if (end == NULL) - end = (char*) page_align((size_t) base); + if (end < base) { + // "end" can be NULL when 1. you are using an old wasm-ld which doesn't + // provide `__heap_end` (< 15.0.7) and 2. something (other libraries + // or maybe your app?) includes a weak reference to `__heap_end` and + // 3. the weak reference is found by the linker before this strong + // reference. + // + // Note: This is a linker bug: https://github.com/llvm/llvm-project/issues/60829 + __builtin_trap(); + } size_t initial_heap_size = end - base; /* Check that initial heap is long enough to serve a minimal allocation request. */ |