Changeset 192814 in webkit for trunk/Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp

Timestamp:

Nov 30, 2015, 12:36:54 PM (10 years ago)

Author:

[email protected]

Message:

implement op_get_rest_length so that we can allocate the rest array with the right size from the start
​https://bugs.webkit.org/show_bug.cgi?id=151467

Reviewed by Geoffrey Garen and Mark Lam.

This patch implements op_get_rest_length which returns the length
that the rest parameter array will be. We're implementing this because
it might be a constant value in the presence of inlining in the DFG.
We will take advantage of this optimization opportunity in a future patch:
​https://bugs.webkit.org/show_bug.cgi?id=151454
to emit better code for op_copy_rest.

op_get_rest_length has two operands:
1) a destination
2) A constant indicating the number of parameters to skip when copying the rest array.

op_get_rest_length lowers to a JSConstant node when we're inlined
and not a varargs call (in this case, we statically know the arguments
length). When that condition isn't met, we lower op_get_rest_length to
GetRestArray. GetRestArray produces its result as an int32.

• bytecode/BytecodeList.json:
• bytecode/BytecodeUseDef.h:

(JSC::computeUsesForBytecodeOffset):
(JSC::computeDefsForBytecodeOffset):

• bytecode/CodeBlock.cpp:

(JSC::CodeBlock::dumpBytecode):

• bytecompiler/BytecodeGenerator.cpp:

(JSC::BytecodeGenerator::emitNewArray):
(JSC::BytecodeGenerator::emitNewArrayWithSize):
(JSC::BytecodeGenerator::emitNewFunction):
(JSC::BytecodeGenerator::emitExpectedFunctionSnippet):
(JSC::BytecodeGenerator::emitRestParameter):

• bytecompiler/BytecodeGenerator.h:
• bytecompiler/NodesCodegen.cpp:

(JSC::RestParameterNode::emit):

• dfg/DFGAbstractInterpreterInlines.h:

(JSC::DFG::AbstractInterpreter<AbstractStateType>::executeEffects):

• dfg/DFGByteCodeParser.cpp:

(JSC::DFG::ByteCodeParser::parseBlock):

• dfg/DFGCapabilities.cpp:

(JSC::DFG::capabilityLevel):

• dfg/DFGClobberize.h:

(JSC::DFG::clobberize):

• dfg/DFGDoesGC.cpp:

(JSC::DFG::doesGC):

• dfg/DFGFixupPhase.cpp:

(JSC::DFG::FixupPhase::fixupNode):

• dfg/DFGMayExit.cpp:

(JSC::DFG::mayExit):

• dfg/DFGNode.h:

(JSC::DFG::Node::numberOfArgumentsToSkip):

• dfg/DFGNodeType.h:
• dfg/DFGOperations.cpp:
• dfg/DFGOperations.h:
• dfg/DFGPredictionPropagationPhase.cpp:

(JSC::DFG::PredictionPropagationPhase::propagate):

• dfg/DFGSafeToExecute.h:

(JSC::DFG::safeToExecute):

• dfg/DFGSpeculativeJIT.cpp:

(JSC::DFG::SpeculativeJIT::compileCopyRest):
(JSC::DFG::SpeculativeJIT::compileGetRestLength):
(JSC::DFG::SpeculativeJIT::compileNotifyWrite):

• dfg/DFGSpeculativeJIT.h:

(JSC::DFG::SpeculativeJIT::callOperation):

• dfg/DFGSpeculativeJIT32_64.cpp:

(JSC::DFG::SpeculativeJIT::compile):

• dfg/DFGSpeculativeJIT64.cpp:

(JSC::DFG::SpeculativeJIT::compile):

• ftl/FTLCapabilities.cpp:

(JSC::FTL::canCompile):

• ftl/FTLLowerDFGToLLVM.cpp:

(JSC::FTL::DFG::LowerDFGToLLVM::compileNode):
(JSC::FTL::DFG::LowerDFGToLLVM::compileCopyRest):
(JSC::FTL::DFG::LowerDFGToLLVM::compileGetRestLength):
(JSC::FTL::DFG::LowerDFGToLLVM::compileNewObject):

• jit/JIT.cpp:

(JSC::JIT::privateCompileMainPass):

• jit/JIT.h:
• jit/JITOpcodes.cpp:

(JSC::JIT::emit_op_copy_rest):
(JSC::JIT::emit_op_get_rest_length):

• llint/LowLevelInterpreter.asm:
• llint/LowLevelInterpreter32_64.asm:
• llint/LowLevelInterpreter64.asm:
• runtime/CommonSlowPaths.cpp:

(JSC::SLOW_PATH_DECL):

File:

• trunk/Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp (modified) (1 diff)

trunk/Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp

@@ -3332 +3332 @@
         }
 
+        case op_get_rest_length: {
+            InlineCallFrame* inlineCallFrame = this->inlineCallFrame();
+            Node* length;
+            if (inlineCallFrame && !inlineCallFrame->isVarargs()) {
+                unsigned argumentsLength = inlineCallFrame->arguments.size() - 1;
+                unsigned numParamsToSkip = currentInstruction[2].u.unsignedValue;
+                JSValue restLength;
+                if (argumentsLength <= numParamsToSkip)
+                    restLength = jsNumber(0);
+                else
+                    restLength = jsNumber(argumentsLength - numParamsToSkip);
+
+                length = jsConstant(restLength);
+            } else
+                length = addToGraph(GetRestLength, OpInfo(currentInstruction[2].u.unsignedValue));
+            set(VirtualRegister(currentInstruction[1].u.operand), length);
+            NEXT_OPCODE(op_get_rest_length);
+        }
+
         case op_copy_rest: {
             noticeArgumentsUse();
-            addToGraph(CopyRest,
-                OpInfo(currentInstruction[2].u.unsignedValue), get(VirtualRegister(currentInstruction[1].u.operand)));
+            Node* array = get(VirtualRegister(currentInstruction[1].u.operand));
+            Node* arrayLength = get(VirtualRegister(currentInstruction[2].u.operand));
+            addToGraph(CopyRest, OpInfo(currentInstruction[3].u.unsignedValue),
+                array, arrayLength);
             NEXT_OPCODE(op_copy_rest);
         }