Adding upstream version 0.0~git20230821.ec4566b.upstream/0.0_git20230821.ec4566b

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

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. */