Fix initial value of sbrk(0)

emcc.py

@@ -3001,6 +3001,8 @@ def do_binaryen(target, asm_target, options, memfile, wasm_binary_target,
       # (we can't add this value when we placed post-emscripten in the proper position in the list of
       # passes because that was before the value was computed)
       options.binaryen_passes += ['--pass-arg=emscripten-sbrk-ptr@%d' % shared.Settings.DYNAMICTOP_PTR]
+      if shared.Settings.STANDALONE_WASM:
+        options.binaryen_passes += ['--pass-arg=emscripten-sbrk-val@%d' % shared.Settings.DYNAMIC_BASE]
     if DEBUG:
       shared.safe_copy(wasm_binary_target, os.path.join(shared.get_emscripten_temp_dir(), os.path.basename(wasm_binary_target) + '.pre-byn'))
     cmd = [os.path.join(binaryen_bin, 'wasm-opt'), wasm_binary_target, '-o', wasm_binary_target] + options.binaryen_passes

emscripten.py

@@ -798,6 +798,8 @@ def apply_memory(js):
 
   logger.debug('global_base: %d stack_base: %d, stack_max: %d, dynamic_base: %d, static bump: %d', memory.global_base, memory.stack_base, memory.stack_max, memory.dynamic_base, memory.static_bump)
 
+  shared.Settings.DYNAMIC_BASE = memory.dynamic_base
+
   return js
 
 

src/runtime_init_memory.js

@@ -77,7 +77,9 @@ updateGlobalBufferAndViews(buffer);
 #if USE_PTHREADS
 if (!ENVIRONMENT_IS_PTHREAD) { // Pthreads have already initialized these variables in src/worker.js, where they were passed to the thread worker at startup time
 #endif
+#if !STANDALONE_WASM // in standalone mode the value is in the wasm
 HEAP32[DYNAMICTOP_PTR>>2] = DYNAMIC_BASE;
+#endif // !STANDALONE_WASM
 #if USE_PTHREADS
 }
 #endif

src/settings.js

@@ -1642,6 +1642,10 @@ var MAIN_READS_PARAMS = 1;
 // The computed location of the pointer to the sbrk position.
 var DYNAMICTOP_PTR = -1;
 
+// The computed initial value of the program break (the sbrk position), which
+// is called DYNAMIC_BASE as it is the start of dynamically-allocated memory.
+var DYNAMIC_BASE = -1;
+
 // Legacy settings that have been removed or renamed.
 // For renamed settings the format is:
 // [OLD_NAME, NEW_NAME]

tests/other/metadce/hello_world_Oz.exports

@@ -1 +1,2 @@
 c
+d

tests/other/metadce/hello_world_Oz.funcs

@@ -4,6 +4,7 @@ $__fwritex
 $__overflow
 $__stdio_write
 $__towrite
+$__wasm_call_ctors
 $fwrite
 $main
 $memcpy

tests/other/metadce/minimal_Oz.exports

@@ -1 +1,2 @@
 a
+b

tests/other/metadce/minimal_Oz.funcs

@@ -1 +1,2 @@
+$__wasm_call_ctors
 $add

tests/test_other.py

@@ -7348,6 +7348,7 @@ def test(p1, p2, p3, last, expected):
       print(first, second, third)
       assert first < second and second < third, [first, second, third]
 
+  @no_wasm_backend('ctor evaller disabled, see https://github.com/emscripten-core/emscripten/issues/9527')
   @uses_canonical_tmp
   @with_env_modify({'EMCC_DEBUG': '1'})
   def test_eval_ctors_debug_output(self):
@@ -8089,7 +8090,7 @@ def strip_numeric_suffixes(funcname):
     # in -O3, -Os and -Oz we metadce, and they shrink it down to the minimal output we want
     'O3': (['-O3'],  2, [], [],          85,  0,  2,  2), # noqa
     'Os': (['-Os'],  2, [], [],          85,  0,  2,  2), # noqa
-    'Oz': (['-Oz'],  2, [], [],          54,  0,  1,  1), # noqa
+    'Oz': (['-Oz'],  2, [], [],          85,  0,  2,  2), # noqa
   })
   @no_fastcomp()
   def test_binaryen_metadce_minimal(self, *args):
@@ -8130,7 +8131,7 @@ def test_binaryen_metadce_cxx_fastcomp(self, *args):
     'O2': (['-O2'],  7, [], ['waka'], 10183,  6,  14, 24), # noqa
     'O3': (['-O3'],  4, [], [],        1957,  4,   2, 12), # noqa; in -O3, -Os and -Oz we metadce
     'Os': (['-Os'],  4, [], [],        1963,  4,   2, 12), # noqa
-    'Oz': (['-Oz'],  4, [], [],        1929,  4,   1, 11), # noqa
+    'Oz': (['-Oz'],  4, [], [],        1929,  4,   2, 12), # noqa
     # finally, check what happens when we export nothing. wasm should be almost empty
     'export_nothing':
           (['-Os', '-s', 'EXPORTED_FUNCTIONS=[]'],

tools/shared.py

@@ -1170,7 +1170,10 @@ def apply_opt_level(cls, opt_level, shrink_level=0, noisy=False):
         cls.attrs['ASSERTIONS'] = 0
         cls.attrs['ALIASING_FUNCTION_POINTERS'] = 1
       if shrink_level >= 2:
-        cls.attrs['EVAL_CTORS'] = 1
+        # Ctor evalling in the wasm backend is disabled due to
+        # https://github.com/emscripten-core/emscripten/issues/9527
+        if not Settings.WASM_BACKEND:
+          cls.attrs['EVAL_CTORS'] = 1
 
     def keys(self):
       return self.attrs.keys()