Changeset 96375 in webkit for trunk/Source/JavaScriptCore/dfg/DFGDriver.cpp

Timestamp:

Sep 29, 2011, 4:17:19 PM (14 years ago)

Author:

[email protected]

Message:

DFG JIT should infer which uses of a variable are not aliased
​https://bugs.webkit.org/show_bug.cgi?id=68593

Reviewed by Oliver Hunt.

This separates how a variable is stored (i.e. its virtual register)
from how it's predicted. Each variable now takes a
VariableAccessData as its operand, instead of the virtual register.
The VariableAccessData stores the operand and the prediction. If
multiple uses of a variable are aliased, their VariableAccessDatas
are unified.

This also adds tracking of which argument values are used. It
correctly observes that an argument value is not used, if the
argument is assigned to inside the function before being used.

This also adds tracking of which variables are live at the head of
a basic block, and separates that from a variable being live at the
tail.

Finally, this communicates to both OSR entry and OSR exit code how
a variable is predicted at a particular point in the code, rather
than just communicating how it was predicted in the entire code
block (since with this patch there is no longer the notion of a
variable having just one prediction for a code block).

• JavaScriptCore.vcproj/JavaScriptCore/JavaScriptCore.vcproj:
• JavaScriptCore.vcproj/WTF/WTF.vcproj:
• JavaScriptCore.xcodeproj/project.pbxproj:
• bytecode/ActionablePrediction.h: Added.

(JSC::actionablePredictionFromPredictedType):
(JSC::valueObeysPrediction):
(JSC::actionablePredictionToString):
(JSC::ActionablePredictions::ActionablePredictions):
(JSC::ActionablePredictions::setArgument):
(JSC::ActionablePredictions::argument):
(JSC::ActionablePredictions::setVariable):
(JSC::ActionablePredictions::variable):
(JSC::ActionablePredictions::argumentUpperBound):
(JSC::ActionablePredictions::variableUpperBound):
(JSC::ActionablePredictions::pack):
(JSC::ActionablePredictions::packVector):

• bytecode/CodeBlock.h:
• bytecode/PredictionTracker.h:
• dfg/DFGByteCodeParser.cpp:

(JSC::DFG::ByteCodeParser::newVariableAccessData):
(JSC::DFG::ByteCodeParser::getLocal):
(JSC::DFG::ByteCodeParser::setLocal):
(JSC::DFG::ByteCodeParser::getArgument):
(JSC::DFG::ByteCodeParser::setArgument):
(JSC::DFG::ByteCodeParser::parseBlock):
(JSC::DFG::ByteCodeParser::processPhiStack):
(JSC::DFG::ByteCodeParser::parse):

• dfg/DFGDriver.cpp:

(JSC::DFG::compile):

• dfg/DFGGraph.cpp:

(JSC::DFG::Graph::nameOfVariableAccessData):
(JSC::DFG::Graph::dump):
(JSC::DFG::Graph::predictArgumentTypes):

• dfg/DFGGraph.h:

(JSC::DFG::operandIsArgument):
(JSC::DFG::VariableRecord::setFirstTime):
(JSC::DFG::BasicBlock::BasicBlock):
(JSC::DFG::Graph::predict):
(JSC::DFG::Graph::getPrediction):

• dfg/DFGJITCompiler.h:

(JSC::DFG::JITCompiler::noticeOSREntry):

• dfg/DFGNode.h:

(JSC::DFG::Node::hasVariableAccessData):
(JSC::DFG::Node::hasLocal):
(JSC::DFG::Node::variableAccessData):
(JSC::DFG::Node::local):

• dfg/DFGOSREntry.cpp:

(JSC::DFG::prepareOSREntry):

• dfg/DFGOSREntry.h:
• dfg/DFGPropagator.cpp:

(JSC::DFG::Propagator::propagateNodePredictions):

• dfg/DFGSpeculativeJIT.cpp:

(JSC::DFG::ValueSource::dump):
(JSC::DFG::OSRExit::OSRExit):
(JSC::DFG::SpeculativeJIT::compile):
(JSC::DFG::SpeculativeJIT::checkArgumentTypes):
(JSC::DFG::SpeculativeJIT::computeValueRecoveryFor):

• dfg/DFGSpeculativeJIT.h:

(JSC::DFG::ValueSource::ValueSource):
(JSC::DFG::ValueSource::forPrediction):
(JSC::DFG::ValueSource::isSet):
(JSC::DFG::ValueSource::kind):
(JSC::DFG::ValueSource::nodeIndex):
(JSC::DFG::ValueSource::nodeIndexFromKind):
(JSC::DFG::ValueSource::kindFromNodeIndex):
(JSC::DFG::SpeculativeJIT::isKnownArray):
(JSC::DFG::SpeculativeJIT::computeValueRecoveryFor):
(JSC::DFG::SpeculativeJIT::SpeculativeJIT):

• dfg/DFGSpeculativeJIT32_64.cpp:

(JSC::DFG::OSRExit::OSRExit):
(JSC::DFG::SpeculativeJIT::compile):
(JSC::DFG::SpeculativeJIT::checkArgumentTypes):
(JSC::DFG::SpeculativeJIT::computeValueRecoveryFor):

• wtf/PackedIntVector.h: Added.

(WTF::PackedIntVector::PackedIntVector):
(WTF::PackedIntVector::operator=):
(WTF::PackedIntVector::size):
(WTF::PackedIntVector::ensureSize):
(WTF::PackedIntVector::resize):
(WTF::PackedIntVector::clearAll):
(WTF::PackedIntVector::get):
(WTF::PackedIntVector::set):
(WTF::PackedIntVector::mask):

• wtf/Platform.h:
• wtf/UnionFind.h: Added.

(WTF::UnionFind::UnionFind):
(WTF::UnionFind::find):
(WTF::UnionFind::unify):

File:

• trunk/Source/JavaScriptCore/dfg/DFGDriver.cpp (modified) (2 diffs)

trunk/Source/JavaScriptCore/dfg/DFGDriver.cpp

@@ -39 +39 @@
 {
     JSGlobalData* globalData = &exec->globalData();
-    Graph dfg(codeBlock->m_numParameters, codeBlock->m_numVars);
+    Graph dfg;
     if (!parse(dfg, globalData, codeBlock))
         return false;
@@ -47 +47 @@
     
     propagate(dfg, globalData, codeBlock);
-    
-    // Save the predictions we've made, so that OSR entry can verify them. Predictions
-    // are saved in the CodeBlock from which we will be doing OSR entry, since the
-    // CodeBlock to which we are OSRing may be replaced at any time.
-    OwnPtr<PredictionTracker> predictions = adoptPtr(new PredictionTracker());
-    *predictions = dfg.predictions();
-    ASSERT(codeBlock->alternative());
-    ASSERT(codeBlock->alternative()->getJITType() == JITCode::BaselineJIT);
-    codeBlock->alternative()->setPredictions(predictions.release());
     
     JITCompiler dataFlowJIT(globalData, dfg, codeBlock);