Address review and rebaseline wasm2js tests.

system/lib/libc/sbrk.c

@@ -58,21 +58,15 @@ uintptr_t* emscripten_get_sbrk_ptr() {
 // Enforce preserving a minimal alignof(maxalign_t) alignment for sbrk.
 #define SBRK_ALIGNMENT (__alignof__(max_align_t))
 
-#ifdef __EMSCRIPTEN_SHARED_MEMORY__
-#define READ_SBRK_PTR(sbrk_ptr) (__c11_atomic_load((_Atomic(uintptr_t)*)(sbrk_ptr), __ATOMIC_SEQ_CST))
-#else
-#define READ_SBRK_PTR(sbrk_ptr) (*(sbrk_ptr))
-#endif
-
 void *sbrk(intptr_t increment_) {
   uintptr_t increment = (uintptr_t)increment_;
   increment = (increment + (SBRK_ALIGNMENT-1)) & ~(SBRK_ALIGNMENT-1);
-  uintptr_t* sbrk_ptr = emscripten_get_sbrk_ptr();
+  _Atomic(uintptr_t)* sbrk_ptr = (_Atomic(uintptr_t)*)emscripten_get_sbrk_ptr();
 
   // To make sbrk thread-safe, implement a CAS loop to update the
   // value of sbrk_ptr.
   while (1) {
-    uintptr_t old_brk = READ_SBRK_PTR(sbrk_ptr);
+    uintptr_t old_brk = __c11_atomic_load(sbrk_ptr, __ATOMIC_SEQ_CST);
     uintptr_t new_brk = old_brk + increment;
     // Check for a) an overflow, which would indicate that we are trying to
     // allocate over maximum addressable memory. and b) if necessary,
@@ -82,16 +76,15 @@ void *sbrk(intptr_t increment_) {
       SET_ERRNO();
       return (void*)-1;
     }
+#ifdef __EMSCRIPTEN_SHARED_MEMORY__
     // Attempt to update the dynamic top to new value. Another thread may have
     // beat this one to the update, in which case we will need to start over
     // by iterating the loop body again.
     uintptr_t expected = old_brk;
 
-#ifdef __EMSCRIPTEN_SHARED_MEMORY__
-    __c11_atomic_compare_exchange_strong(
-        (_Atomic(uintptr_t)*)sbrk_ptr,
-        &expected, new_brk,
-        __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
+    __c11_atomic_compare_exchange_strong(sbrk_ptr,
+      &expected, new_brk, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
+
     if (expected != old_brk) continue; // CAS failed, another thread raced in between.
 #else
     *sbrk_ptr = new_brk;

test/code_size/hello_webgl2_wasm.json

@@ -4,7 +4,7 @@
   "a.js": 4699,
   "a.js.gz": 2419,
   "a.wasm": 10482,
-  "a.wasm.gz": 6726,
+  "a.wasm.gz": 6728,
   "total": 15750,
-  "total_gz": 9524
+  "total_gz": 9526
 }

test/code_size/hello_webgl2_wasm2js.json

@@ -1,10 +1,10 @@
 {
   "a.html": 567,
   "a.html.gz": 379,
-  "a.js": 18004,
-  "a.js.gz": 8135,
+  "a.js": 18025,
+  "a.js.gz": 8138,
   "a.mem": 3123,
   "a.mem.gz": 2693,
-  "total": 21694,
-  "total_gz": 11207
+  "total": 21715,
+  "total_gz": 11210
 }

test/code_size/hello_webgl_wasm.json

@@ -4,7 +4,7 @@
   "a.js": 4185,
   "a.js.gz": 2243,
   "a.wasm": 10482,
-  "a.wasm.gz": 6726,
+  "a.wasm.gz": 6728,
   "total": 15236,
-  "total_gz": 9348
+  "total_gz": 9350
 }

test/code_size/hello_webgl_wasm2js.json

@@ -1,10 +1,10 @@
 {
   "a.html": 567,
   "a.html.gz": 379,
-  "a.js": 17481,
-  "a.js.gz": 7960,
+  "a.js": 17502,
+  "a.js.gz": 7961,
   "a.mem": 3123,
   "a.mem.gz": 2693,
-  "total": 21171,
-  "total_gz": 11032
+  "total": 21192,
+  "total_gz": 11033
 }