AuroraMiddleware/v8
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Using unsigned shifts and masks when dealing with 64-bit addresses.

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BUG=v8:1037

Review URL: http://codereview.chromium.org/6242005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6388 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
antonm@chromium.org 2011-01-19 11:16:23 +00:00
parent 890a0f6b52
commit b0abe13ed2
3 changed files with 11 additions and 7 deletions
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10
include/v8.h
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@ -3367,7 +3367,7 @@ template <> struct SmiTagging<4> {
// For 32-bit systems any 2 bytes aligned pointer can be encoded as smi
// with a plain reinterpret_cast.
static const intptr_t kEncodablePointerMask = 0x1;
static const uintptr_t kEncodablePointerMask = 0x1;
static const int kPointerToSmiShift = 0;
};
@ -3387,8 +3387,8 @@ template <> struct SmiTagging<8> {
// It might be not enough to cover stack allocated objects on some platforms.
static const int kPointerAlignment = 3;
static const intptr_t kEncodablePointerMask =
~(intptr_t(0xffffffff) << kPointerAlignment);
static const uintptr_t kEncodablePointerMask =
~(uintptr_t(0xffffffff) << kPointerAlignment);
static const int kPointerToSmiShift =
kSmiTagSize + kSmiShiftSize - kPointerAlignment;
@ -3397,7 +3397,7 @@ template <> struct SmiTagging<8> {
typedef SmiTagging<kApiPointerSize> PlatformSmiTagging;
const int kSmiShiftSize = PlatformSmiTagging::kSmiShiftSize;
const int kSmiValueSize = PlatformSmiTagging::kSmiValueSize;
const intptr_t kEncodablePointerMask =
const uintptr_t kEncodablePointerMask =
PlatformSmiTagging::kEncodablePointerMask;
const int kPointerToSmiShift = PlatformSmiTagging::kPointerToSmiShift;
@ -3457,7 +3457,7 @@ class Internals {
}
static inline void* GetExternalPointerFromSmi(internal::Object* value) {
const intptr_t address = reinterpret_cast<intptr_t>(value);
const uintptr_t address = reinterpret_cast<uintptr_t>(value);
return reinterpret_cast<void*>(address >> kPointerToSmiShift);
}

4
src/api.cc
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@ -3267,14 +3267,14 @@ void v8::Object::SetInternalField(int index, v8::Handle<Value> value) {
static bool CanBeEncodedAsSmi(void* ptr) {
const intptr_t address = reinterpret_cast<intptr_t>(ptr);
const uintptr_t address = reinterpret_cast<uintptr_t>(ptr);
return ((address & i::kEncodablePointerMask) == 0);
}
static i::Smi* EncodeAsSmi(void* ptr) {
ASSERT(CanBeEncodedAsSmi(ptr));
const intptr_t address = reinterpret_cast<intptr_t>(ptr);
const uintptr_t address = reinterpret_cast<uintptr_t>(ptr);
i::Smi* result = reinterpret_cast<i::Smi*>(address << i::kPointerToSmiShift);
ASSERT(i::Internals::HasSmiTag(result));
ASSERT_EQ(result, i::Smi::FromInt(result->value()));

4
test/cctest/test-api.cc
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@ -874,6 +874,10 @@ THREADED_TEST(ExternalWrap) {
TestExternalPointerWrapping();
#if defined(V8_HOST_ARCH_X64)
// Check a value with a leading 1 bit in x64 Smi encoding.
expected_ptr = reinterpret_cast<void*>(0x400000000);
TestExternalPointerWrapping();
expected_ptr = reinterpret_cast<void*>(0xdeadbeefdeadbeef);
TestExternalPointerWrapping();