DFGLazyJSValue.cpp [plain text]
#include "config.h"
#include "DFGLazyJSValue.h"
#if ENABLE(DFG_JIT)
#include "CCallHelpers.h"
#include "DFGGraph.h"
#include "JSCInlines.h"
#include "LinkBuffer.h"
namespace JSC { namespace DFG {
LazyJSValue LazyJSValue::newString(Graph& graph, const String& string)
{
LazyJSValue result;
result.m_kind = NewStringImpl;
result.u.stringImpl = graph.m_localStrings.add(string).iterator->impl();
return result;
}
JSValue LazyJSValue::getValue(VM& vm) const
{
switch (m_kind) {
case KnownValue:
return value()->value();
case SingleCharacterString:
return jsSingleCharacterString(&vm, u.character);
case KnownStringImpl:
case NewStringImpl:
return jsString(&vm, u.stringImpl);
}
RELEASE_ASSERT_NOT_REACHED();
return JSValue();
}
static TriState equalToSingleCharacter(JSValue value, UChar character)
{
if (!value.isString())
return FalseTriState;
JSString* jsString = asString(value);
if (jsString->length() != 1)
return FalseTriState;
const StringImpl* string = jsString->tryGetValueImpl();
if (!string)
return MixedTriState;
return triState(string->at(0) == character);
}
static TriState equalToStringImpl(JSValue value, StringImpl* stringImpl)
{
if (!value.isString())
return FalseTriState;
JSString* jsString = asString(value);
const StringImpl* string = jsString->tryGetValueImpl();
if (!string)
return MixedTriState;
return triState(WTF::equal(stringImpl, string));
}
const StringImpl* LazyJSValue::tryGetStringImpl() const
{
switch (m_kind) {
case KnownStringImpl:
case NewStringImpl:
return u.stringImpl;
case KnownValue:
if (JSString* string = value()->dynamicCast<JSString*>())
return string->tryGetValueImpl();
return nullptr;
default:
return nullptr;
}
}
String LazyJSValue::tryGetString(Graph& graph) const
{
switch (m_kind) {
case NewStringImpl:
return u.stringImpl;
case SingleCharacterString:
return String(&u.character, 1);
default:
if (const StringImpl* string = tryGetStringImpl()) {
unsigned ginormousStringLength = 10000;
if (string->length() > ginormousStringLength)
return String();
auto result = graph.m_copiedStrings.add(string, String());
if (result.isNewEntry)
result.iterator->value = string->isolatedCopy();
return result.iterator->value;
}
return String();
}
}
TriState LazyJSValue::strictEqual(const LazyJSValue& other) const
{
switch (m_kind) {
case KnownValue:
switch (other.m_kind) {
case KnownValue:
return JSValue::pureStrictEqual(value()->value(), other.value()->value());
case SingleCharacterString:
return equalToSingleCharacter(value()->value(), other.character());
case KnownStringImpl:
case NewStringImpl:
return equalToStringImpl(value()->value(), other.stringImpl());
}
break;
case SingleCharacterString:
switch (other.m_kind) {
case SingleCharacterString:
return triState(character() == other.character());
case KnownStringImpl:
case NewStringImpl:
if (other.stringImpl()->length() != 1)
return FalseTriState;
return triState(other.stringImpl()->at(0) == character());
default:
return other.strictEqual(*this);
}
break;
case KnownStringImpl:
case NewStringImpl:
switch (other.m_kind) {
case KnownStringImpl:
case NewStringImpl:
return triState(WTF::equal(stringImpl(), other.stringImpl()));
default:
return other.strictEqual(*this);
}
break;
}
RELEASE_ASSERT_NOT_REACHED();
return FalseTriState;
}
uintptr_t LazyJSValue::switchLookupValue(SwitchKind kind) const
{
switch (m_kind) {
case KnownValue:
switch (kind) {
case SwitchImm:
return value()->value().asInt32();
case SwitchCell:
return bitwise_cast<uintptr_t>(value()->value().asCell());
default:
RELEASE_ASSERT_NOT_REACHED();
return 0;
}
case SingleCharacterString:
switch (kind) {
case SwitchChar:
return character();
default:
RELEASE_ASSERT_NOT_REACHED();
return 0;
}
default:
RELEASE_ASSERT_NOT_REACHED();
return 0;
}
}
void LazyJSValue::emit(CCallHelpers& jit, JSValueRegs result) const
{
if (m_kind == KnownValue) {
jit.moveValue(value()->value(), result);
return;
}
#if USE(JSVALUE32_64)
jit.move(CCallHelpers::TrustedImm32(JSValue::CellTag), result.tagGPR());
#endif
CCallHelpers::DataLabelPtr label = jit.moveWithPatch(
CCallHelpers::TrustedImmPtr(static_cast<size_t>(0xd1e7beeflu)),
result.payloadGPR());
LazyJSValue thisValue = *this;
if (m_kind == NewStringImpl)
thisValue.u.stringImpl->ref();
CodeBlock* codeBlock = jit.codeBlock();
jit.addLinkTask(
[codeBlock, label, thisValue] (LinkBuffer& linkBuffer) {
JSValue realValue = thisValue.getValue(linkBuffer.vm());
RELEASE_ASSERT(realValue.isCell());
codeBlock->addConstant(realValue);
if (thisValue.m_kind == NewStringImpl)
thisValue.u.stringImpl->deref();
linkBuffer.patch(label, realValue.asCell());
});
}
void LazyJSValue::dumpInContext(PrintStream& out, DumpContext* context) const
{
switch (m_kind) {
case KnownValue:
value()->dumpInContext(out, context);
return;
case SingleCharacterString:
out.print("Lazy:SingleCharacterString(");
out.printf("%04X", static_cast<unsigned>(character()));
out.print(" / ", StringImpl::utf8ForCharacters(&u.character, 1), ")");
return;
case KnownStringImpl:
out.print("Lazy:KnownString(", stringImpl(), ")");
return;
case NewStringImpl:
out.print("Lazy:NewString(", stringImpl(), ")");
return;
}
RELEASE_ASSERT_NOT_REACHED();
}
void LazyJSValue::dump(PrintStream& out) const
{
dumpInContext(out, 0);
}
} }
#endif // ENABLE(DFG_JIT)