Changeset 128544 in webkit for trunk/Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp

Timestamp:

Sep 13, 2012, 7:17:01 PM (13 years ago)

Author:

[email protected]

Message:

Refactored the DFG to make fewer assumptions about variable capture
​https://bugs.webkit.org/show_bug.cgi?id=96680

Reviewed by Gavin Barraclough.

A variable capture optimization patch I'm working on broke DFG
correctness and the arguments simplification optimization phase, so I've
refactored both to make fewer assumptions about variable capture.

• bytecode/CodeBlock.h:

(JSC::CodeBlock::isCaptured): This is the new One True Way to find out
if a variable was captured. This gives us a single point of maintenance
as we chagne capture behavior.

• dfg/DFGAbstractState.cpp:

(JSC::DFG::AbstractState::clobberCapturedVars): Don't assume that captured
variables have any particular location. Instead, ask the One True Function.

• dfg/DFGArgumentsSimplificationPhase.cpp:

(JSC::DFG::ArgumentsSimplificationPhase::run):
(JSC::DFG::ArgumentsSimplificationPhase::observeProperArgumentsUse):
(JSC::DFG::ArgumentsSimplificationPhase::isOKToOptimize): Mechanical
changes to separate being captured from being 'arguments'. What used
to be

if (captured)

if (arguments)

x

y

is now

if (arguments)

x
y

else if (captured)

y

• dfg/DFGByteCodeParser.cpp:

(JSC::DFG::ByteCodeParser::getLocal):
(JSC::DFG::ByteCodeParser::setLocal):
(JSC::DFG::ByteCodeParser::getArgument):
(JSC::DFG::ByteCodeParser::setArgument):
(JSC::DFG::ByteCodeParser::flushDirect):
(JSC::DFG::ByteCodeParser::parseBlock):
(JSC::DFG::ByteCodeParser::InlineStackEntry::InlineStackEntry):

• dfg/DFGSpeculativeJIT.cpp:

(JSC::DFG::SpeculativeJIT::compile): Use the One True Function.

File:

• trunk/Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp (modified) (7 diffs)

trunk/Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp

@@ -194 +194 @@
     {
         NodeIndex nodeIndex = m_currentBlock->variablesAtTail.local(operand);
-        bool isCaptured = m_codeBlock->localIsCaptured(m_inlineStackTop->m_inlineCallFrame, operand);
+        bool isCaptured = m_codeBlock->isCaptured(operand, m_inlineStackTop->m_inlineCallFrame);
         
         if (nodeIndex != NoNode) {
@@ -254 +254 @@
     void setLocal(unsigned operand, NodeIndex value, SetMode setMode = NormalSet)
     {
-        bool isCaptured = m_codeBlock->localIsCaptured(m_inlineStackTop->m_inlineCallFrame, operand);
+        bool isCaptured = m_codeBlock->isCaptured(operand, m_inlineStackTop->m_inlineCallFrame);
         
         if (setMode == NormalSet) {
@@ -273 +273 @@
     {
         unsigned argument = operandToArgument(operand);
-        
-        bool isCaptured = m_codeBlock->argumentIsCaptured(argument);
-        
         ASSERT(argument < m_numArguments);
         
         NodeIndex nodeIndex = m_currentBlock->variablesAtTail.argument(argument);
+        bool isCaptured = m_codeBlock->isCaptured(operand);
 
         if (nodeIndex != NoNode) {
@@ -340 +338 @@
     {
         unsigned argument = operandToArgument(operand);
-        bool isCaptured = m_codeBlock->argumentIsCaptured(argument);
-        
         ASSERT(argument < m_numArguments);
         
+        bool isCaptured = m_codeBlock->isCaptured(operand);
+
         // Always flush arguments, except for 'this'.
         if (argument && setMode == NormalSet)
@@ -403 +401 @@
         // some other local variable.
         
-        bool isCaptured = m_codeBlock->isCaptured(m_inlineStackTop->m_inlineCallFrame, operand);
+        bool isCaptured = m_codeBlock->isCaptured(operand, m_inlineStackTop->m_inlineCallFrame);
         
         ASSERT(operand < FirstConstantRegisterIndex);
@@ -1774 +1772 @@
         for (unsigned argument = 0; argument < m_numArguments; ++argument) {
             VariableAccessData* variable = newVariableAccessData(
-                argumentToOperand(argument), m_codeBlock->argumentIsCaptured(argument));
+                argumentToOperand(argument), m_codeBlock->isCaptured(argumentToOperand(argument)));
             variable->mergeStructureCheckHoistingFailed(
                 m_inlineStackTop->m_exitProfile.hasExitSite(m_currentIndex, BadCache));
@@ -3191 +3189 @@
             inlineCallFrame.capturedVars = inlineCallFrame.caller.inlineCallFrame->capturedVars;
         else {
-            for (int i = byteCodeParser->m_codeBlock->m_numCapturedVars; i--;)
-                inlineCallFrame.capturedVars.set(i);
-        }
-        
-        if (codeBlock->argumentsAreCaptured()) {
-            for (int i = argumentCountIncludingThis; i--;)
+            for (int i = byteCodeParser->m_codeBlock->m_numVars; i--;) {
+                if (byteCodeParser->m_codeBlock->isCaptured(i))
+                    inlineCallFrame.capturedVars.set(i);
+            }
+        }
+
+        for (int i = argumentCountIncludingThis; i--;) {
+            if (codeBlock->isCaptured(argumentToOperand(i)))
                 inlineCallFrame.capturedVars.set(argumentToOperand(i) + inlineCallFrame.stackOffset);
         }
-        for (int i = codeBlock->m_numCapturedVars; i--;)
-            inlineCallFrame.capturedVars.set(i + inlineCallFrame.stackOffset);
-        
+        for (size_t i = codeBlock->m_numVars; i--;) {
+            if (codeBlock->isCaptured(i))
+                inlineCallFrame.capturedVars.set(i + inlineCallFrame.stackOffset);
+        }
+
 #if DFG_ENABLE(DEBUG_VERBOSE)
         dataLog("Current captured variables: ");