Merge pull request #8837 from ziglang/cc-wasm32-wasi

cc,wasi: ship WASI libc and autobuild it when needed

1 files changed, 98 insertions, 0 deletions

diff --git a/lib/libc/wasi/dlmalloc/src/dlmalloc.c b/lib/libc/wasi/dlmalloc/src/dlmalloc.c
new file mode 100644
index 0000000000..331536b44f
--- /dev/null
+++ b/lib/libc/wasi/dlmalloc/src/dlmalloc.c
@@ -0,0 +1,98 @@
+// This file is a wrapper around malloc.c, which is the upstream source file.
+// It sets configuration flags and controls which symbols are exported.
+
+#include <stddef.h>
+#include <malloc.h>
+
+// Define configuration macros for dlmalloc.
+
+// WebAssembly doesn't have mmap-style memory allocation.
+#define HAVE_MMAP 0
+
+// WebAssembly doesn't support shrinking linear memory.
+#define MORECORE_CANNOT_TRIM 1
+
+// Disable sanity checks to reduce code size.
+#define ABORT __builtin_unreachable()
+
+// If threads are enabled, enable support for threads.
+#ifdef _REENTRANT
+#define USE_LOCKS 1
+#endif
+
+// Make malloc deterministic.
+#define LACKS_TIME_H 1
+
+// Disable malloc statistics generation to reduce code size.
+#define NO_MALLINFO 1
+#define NO_MALLOC_STATS 1
+
+// Align malloc regions to 16, to avoid unaligned SIMD accesses.
+#define MALLOC_ALIGNMENT 16
+
+// Declare errno values used by dlmalloc. We define them like this to avoid
+// putting specific errno values in the ABI.
+extern const int __ENOMEM;
+#define ENOMEM __ENOMEM
+extern const int __EINVAL;
+#define EINVAL __EINVAL
+
+// Define USE_DL_PREFIX so that we leave dlmalloc's names prefixed with 'dl'.
+// We define them as "static", and we wrap them with public names below. This
+// serves two purposes:
+//
+// One is to make it easy to control which symbols are exported; dlmalloc
+// defines several non-standard functions and we wish to explicitly control
+// which functions are part of our public-facing interface.
+//
+// The other is to protect against compilers optimizing based on the assumption
+// that they know what functions with names like "malloc" do. Code in the
+// implementation will call functions like "dlmalloc" and assume it can use
+// the resulting pointers to access the metadata outside of the nominally
+// allocated objects. However, if the function were named "malloc", compilers
+// might see code like that and assume it has undefined behavior and can be
+// optimized away. By using "dlmalloc" in the implementation, we don't need
+// -fno-builtin to avoid this problem.
+#define USE_DL_PREFIX 1
+#define DLMALLOC_EXPORT static inline
+
+// This isn't declared with DLMALLOC_EXPORT so make it static explicitly.
+static size_t dlmalloc_usable_size(void*);
+
+// Include the upstream dlmalloc's malloc.c.
+#include "malloc.c"
+
+// Export the public names.
+
+void *malloc(size_t size) {
+    return dlmalloc(size);
+}
+
+void free(void *ptr) {
+    dlfree(ptr);
+}
+
+void *calloc(size_t nmemb, size_t size) {
+    return dlcalloc(nmemb, size);
+}
+
+void *realloc(void *ptr, size_t size) {
+    return dlrealloc(ptr, size);
+}
+
+int posix_memalign(void **memptr, size_t alignment, size_t size) {
+    return dlposix_memalign(memptr, alignment, size);
+}
+
+void* aligned_alloc(size_t alignment, size_t bytes) {
+    return dlmemalign(alignment, bytes);
+}
+
+size_t malloc_usable_size(void *ptr) {
+    return dlmalloc_usable_size(ptr);
+}
+
+// Define these to satisfy musl references.
+void *__libc_malloc(size_t) __attribute__((alias("malloc")));
+void __libc_free(void *) __attribute__((alias("free")));
+void *__libc_calloc(size_t nmemb, size_t size) __attribute__((alias("calloc")));