AuroraMiddleware/v8
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- Do not allocate proxy objects if the pointer can be wrapped in a Smi representation.

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Review URL: http://codereview.chromium.org/42466

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1568 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
iposva@chromium.org 2009-03-20 22:13:50 +00:00
parent 80ce1b2500
commit 1db91bee34
4 changed files with 37 additions and 3 deletions
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4
include/v8.h
View File

@ -1151,6 +1151,10 @@ class V8EXPORT External : public Value {
static External* Cast(Value* obj);
void* Value() const;
private:
enum {
kAlignedPointerMask = 3,
kAlignedPointerShift = 2
};
External();
};

15
src/api.cc
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@ -1447,7 +1447,7 @@ Local<Integer> Value::ToInteger() const {
External* External::Cast(v8::Value* that) {
if (IsDeadCheck("v8::External::Cast()")) return 0;
i::Handle<i::Object> obj = Utils::OpenHandle(that);
ApiCheck(obj->IsProxy(),
ApiCheck(obj->IsProxy() || obj->IsSmi(),
"v8::External::Cast()",
"Could not convert to external");
return static_cast<External*>(that);
@ -2229,6 +2229,11 @@ int32_t Int32::Value() const {
void* External::Value() const {
if (IsDeadCheck("v8::External::Value()")) return 0;
i::Handle<i::Object> obj = Utils::OpenHandle(this);
if (obj->IsSmi()) {
// The external value was an aligned pointer.
return reinterpret_cast<void*>(
i::Smi::cast(*obj)->value() << kAlignedPointerShift);
}
return reinterpret_cast<void*>(i::Proxy::cast(*obj)->proxy());
}
@ -2467,8 +2472,14 @@ Local<External> v8::External::New(void* data) {
STATIC_ASSERT(sizeof(data) == sizeof(i::Address));
LOG_API("External::New");
EnsureInitialized("v8::External::New()");
i::Handle<i::Proxy> obj = i::Factory::NewProxy(static_cast<i::Address>(data));
if ((reinterpret_cast<intptr_t>(data) & kAlignedPointerMask) == 0) {
uintptr_t data_ptr = reinterpret_cast<uintptr_t>(data);
int data_value = static_cast<int>(data_ptr >> kAlignedPointerShift);
STATIC_ASSERT(sizeof(data_ptr) == sizeof(data_value));
i::Handle<i::Smi> obj(i::Smi::FromInt(data_value));
return Utils::ToLocal(obj);
}
return Utils::ToLocal(i::Factory::NewProxy(static_cast<i::Address>(data)));
}

3
src/api.h
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@ -181,6 +181,8 @@ class Utils {
v8::internal::Handle<v8::internal::JSArray> obj);
static inline Local<External> ToLocal(
v8::internal::Handle<v8::internal::Proxy> obj);
static inline Local<External> ToLocal(
v8::internal::Handle<v8::internal::Smi> obj);
static inline Local<Message> MessageToLocal(
v8::internal::Handle<v8::internal::Object> obj);
static inline Local<Number> NumberToLocal(
@ -256,6 +258,7 @@ MAKE_TO_LOCAL(ToLocal, String, String)
MAKE_TO_LOCAL(ToLocal, JSObject, Object)
MAKE_TO_LOCAL(ToLocal, JSArray, Array)
MAKE_TO_LOCAL(ToLocal, Proxy, External)
MAKE_TO_LOCAL(ToLocal, Smi, External)
MAKE_TO_LOCAL(ToLocal, FunctionTemplateInfo, FunctionTemplate)
MAKE_TO_LOCAL(ToLocal, ObjectTemplateInfo, ObjectTemplate)
MAKE_TO_LOCAL(ToLocal, SignatureInfo, Signature)

16
test/cctest/test-api.cc
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@ -1339,6 +1339,22 @@ THREADED_TEST(External) {
CHECK_EQ(x, 3);
*ptr = 10;
CHECK_EQ(x, 10);
// Make sure unaligned pointers are wrapped properly.
char* data = "0123456789";
Local<v8::External> zero = v8::External::New(&data[0]);
Local<v8::External> one = v8::External::New(&data[1]);
Local<v8::External> two = v8::External::New(&data[2]);
Local<v8::External> three = v8::External::New(&data[3]);
char* char_ptr = reinterpret_cast<char*>(zero->Value());
CHECK_EQ('0', *char_ptr);
char_ptr = reinterpret_cast<char*>(one->Value());
CHECK_EQ('1', *char_ptr);
char_ptr = reinterpret_cast<char*>(two->Value());
CHECK_EQ('2', *char_ptr);
char_ptr = reinterpret_cast<char*>(three->Value());
CHECK_EQ('3', *char_ptr);
}