Fix stack alignment corruption for MinGW32 build

test/cctest/test-assembler-ia32.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 455 matching lines @@
       Code::ComputeFlags(Code::STUB),
       Handle<Code>())->ToObjectChecked());
   CHECK(code->IsCode());
 
   F0 f = FUNCTION_CAST<F0>(code->entry());
   int res = f();
   CHECK_EQ(42, res);
 }
 
 
+#ifdef __GNUC__
+#define ELEMENT_COUNT 4
+
+void DoSSE2(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  Isolate* isolate = reinterpret_cast<Isolate*>(CcTest::isolate());
+  HandleScope scope(isolate);
+
+  CHECK(args[0]->IsArray());
+  v8::Local<v8::Array> vec = v8::Local<v8::Array>::Cast(args[0]);
+  CHECK_EQ(ELEMENT_COUNT, vec->Length());
+
+  v8::internal::byte buffer[256];
+  Assembler assm(isolate, buffer, sizeof buffer);
+
+  if (CpuFeatures::IsSupported(SSE2)) {

[Jakob Kummerow, 2013/07/02 15:24:18]

I think you should just ASSERT(CpuFeatures::IsSupported(SSE2)) at the beginning
of this function to make it clear that it must not be called when SSE2 is not
supported.

+    CpuFeatureScope fscope(&assm, SSE2);
+
+    // Remove return address from the stack for fix stack frame alignment

[Jakob Kummerow, 2013/07/02 15:24:18]

nit: All comments should end with appropriate punctuation, e.g. a full stop.
(This applies to pretty much all comments in this patch.)

+    __ pop(ecx);
+
+    // Store input vector on the stack
+    for (int i = 0; i < ELEMENT_COUNT; ++i)
+      __ push(Immediate(vec->Get(i)->Int32Value()));

[Jakob Kummerow, 2013/07/02 15:24:18]

nit: {} please

+
+    // Read vector into a xmm register
+    __ pxor(xmm0, xmm0);
+    __ movdqa(xmm0, Operand(esp, 0));
+    // Create mask and store it in the return register
+    __ movmskps(eax, xmm0);
+
+    // Remove unused data from the stack
+    __ add(esp, Immediate(ELEMENT_COUNT * sizeof(int32_t)));
+    // Restore return address
+    __ push(ecx);
+
+    __ ret(0);
+  }
+
+  CodeDesc desc;
+  assm.GetCode(&desc);
+
+  Object* code = isolate->heap()->CreateCode(
+      desc,
+      Code::ComputeFlags(Code::STUB),
+      Handle<Code>())->ToObjectChecked();
+  CHECK(code->IsCode());
+
+  F0 f = FUNCTION_CAST<F0>(Code::cast(code)->entry());
+#ifdef OBJECT_PRINT
+  Code::cast(code)->Print();

[Jakob Kummerow, 2013/07/02 15:24:18]

debugging leftover?

+#endif
+  int res = f();
+  ::printf("f() = %d\n", res);

[Jakob Kummerow, 2013/07/02 15:24:18]

debugging leftover?

+  args.GetReturnValue().Set(v8::Integer::New(res));
+}
+
+TEST(StackAlignmentForSSE2) {
+  CcTest::InitializeVM();
+  if (!CpuFeatures::IsSupported(SSE2)) return;
+
+  CHECK_EQ(0, OS::ActivationFrameAlignment() % 16);
+
+  v8::Isolate* isolate = v8::Isolate::GetCurrent();
+  v8::HandleScope handle_scope(isolate);
+  v8::Handle<v8::ObjectTemplate> global_template = v8::ObjectTemplate::New();
+  global_template->Set(v8_str("do_sse2"), v8::FunctionTemplate::New(DoSSE2));
+
+  LocalContext env(NULL, global_template);
+  CompileRun(
+    "function foo(vec) {"

[Jakob Kummerow, 2013/07/02 15:24:18]

nit: indentation (4 spaces when you break inside a call's arguments list)

+    " return do_sse2(vec);"

[Jakob Kummerow, 2013/07/02 15:24:18]

nit: indentation (2 spaces inside function body, i.e.: "  return ...)

+    "}");
+
+  v8::Local<v8::Object> global_object = env->Global();
+  v8::Local<v8::Function> foo =
+    v8::Local<v8::Function>::Cast(global_object->Get(v8_str("foo")));

[Jakob Kummerow, 2013/07/02 15:24:18]

nit: indentation (4 spaces when you break after '=')

+
+  int32_t vec[ELEMENT_COUNT] = { -1, 1, 1, 1 };
+  v8::Local<v8::Array> v8_vec = v8::Array::New(ELEMENT_COUNT);
+  for (int i = 0; i < ELEMENT_COUNT; i++)
+    v8_vec->Set(i, v8_num(vec[i]));

[Jakob Kummerow, 2013/07/02 15:24:18]

nit: {} please

+
+  v8::Local<v8::Value> args[] = { v8_vec };
+  v8::Local<v8::Value> result = foo->Call(global_object, 1, args);
+
+  // The mask should be 0b1000
+  CHECK_EQ(8, result->Int32Value());
+}
+
+#undef ELEMENT_COUNT
+#endif  // __GNUC__
+
+

[Jakob Kummerow, 2013/07/02 15:24:18]

nit: two empty lines is enough

 
 
 #undef __