[wasm]: Load and store globals properly on big-endian

TEST=wasm-spec-tests/tests/exports,wasm-spec-tests/tests/data

Change-Id: I5c1001b00f2a7eab41e6e143afa19803969c0fe4
Reviewed-on: https://chromium-review.googlesource.com/1181022Reviewed-by: Junliang Yan <jyan@ca.ibm.com>
Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Sreten Kovacevic <skovacevic@wavecomp.com>
Cr-Commit-Position: refs/heads/master@{#55274}

src/wasm/module-compiler.cc

@@ -1294,7 +1294,8 @@ uint32_t InstanceBuilder::EvalUint32InitExpr(const WasmInitExpr& expr) {
       return expr.val.i32_const;
     case WasmInitExpr::kGlobalIndex: {
       uint32_t offset = module_->globals[expr.val.global_index].offset;
-      return *reinterpret_cast<uint32_t*>(raw_buffer_ptr(globals_, offset));
+      return ReadLittleEndianValue<uint32_t>(
+          reinterpret_cast<Address>(raw_buffer_ptr(globals_, offset)));
     }
     default:
       UNREACHABLE();

src/wasm/wasm-objects-inl.h

@@ -108,28 +108,36 @@ Address WasmGlobalObject::address() const {
   return Address(array_buffer()->backing_store()) + offset();
 }
 
-int32_t WasmGlobalObject::GetI32() { return Memory::int32_at(address()); }
+int32_t WasmGlobalObject::GetI32() {
+  return ReadLittleEndianValue<int32_t>(address());
+}
 
-int64_t WasmGlobalObject::GetI64() { return Memory::int64_at(address()); }
+int64_t WasmGlobalObject::GetI64() {
+  return ReadLittleEndianValue<int64_t>(address());
+}
 
-float WasmGlobalObject::GetF32() { return Memory::float_at(address()); }
+float WasmGlobalObject::GetF32() {
+  return ReadLittleEndianValue<float>(address());
+}
 
-double WasmGlobalObject::GetF64() { return Memory::double_at(address()); }
+double WasmGlobalObject::GetF64() {
+  return ReadLittleEndianValue<double>(address());
+}
 
 void WasmGlobalObject::SetI32(int32_t value) {
-  Memory::int32_at(address()) = value;
+  WriteLittleEndianValue<int32_t>(address(), value);
 }
 
 void WasmGlobalObject::SetI64(int64_t value) {
-  Memory::int64_at(address()) = value;
+  WriteLittleEndianValue<int64_t>(address(), value);
 }
 
 void WasmGlobalObject::SetF32(float value) {
-  Memory::float_at(address()) = value;
+  WriteLittleEndianValue<float>(address(), value);
 }
 
 void WasmGlobalObject::SetF64(double value) {
-  Memory::double_at(address()) = value;
+  WriteLittleEndianValue<double>(address(), value);
 }
 
 // WasmInstanceObject