Changeset 183724 in webkit for trunk/Source/JavaScriptCore/runtime/SmallStrings.h

Timestamp:

May 2, 2015, 5:15:27 PM (10 years ago)

Author:

[email protected]

Message:

TypeOf should be fast
​https://bugs.webkit.org/show_bug.cgi?id=144396

Reviewed by Geoffrey Garen.

Adds comprehensive support for fast typeof to the optimizing JITs. Calls into the runtime
are only used for very exotic objects - they must have either the MasqueradesAsUndefined or
TypeOfShouldCallGetCallData type flags set. All other cases are handled inline.

This means optimizing IsObjectOrNull, IsFunction, and TypeOf - all node types that used to
rely heavily on C++ calls to fulfill their function.

Because TypeOf is now so fast, we no longer need to do any speculations on this node.

In the FTL, we take this further by querying AI for each branch in the TypeOf decision tree.
This means that if the TypeOf is dominated by any type checks, we will automatically prune
out cases that are redundant.

This patch anticipates the addition of SwitchTypeOf or something like that. So, the TypeOf
code generation is designed to be reusable.

This is a speed-up on most typeof benchmarks. But, it is a slow-down on benchmarks that take
the exotic call trap hook. That hook is now in a deeper slow path than before.

• CMakeLists.txt:
• JavaScriptCore.vcxproj/JavaScriptCore.vcxproj:
• JavaScriptCore.xcodeproj/project.pbxproj:
• dfg/DFGClobberize.h:

(JSC::DFG::clobberize): TypeOf was pure all along, but we failed to realize this.

• dfg/DFGFixupPhase.cpp:

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

• dfg/DFGHeapLocation.cpp:

(WTF::printInternal):

• dfg/DFGHeapLocation.h:
• dfg/DFGOperations.cpp:
• dfg/DFGOperations.h:
• dfg/DFGSpeculativeJIT.cpp:

(JSC::DFG::SpeculativeJIT::compileIsObjectOrNull):
(JSC::DFG::SpeculativeJIT::compileIsFunction):
(JSC::DFG::SpeculativeJIT::compileTypeOf):

• dfg/DFGSpeculativeJIT.h:

(JSC::DFG::SpeculativeJIT::blessedBooleanResult):
(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/FTLIntrinsicRepository.h:
• ftl/FTLLowerDFGToLLVM.cpp:

(JSC::FTL::LowerDFGToLLVM::compileNode):
(JSC::FTL::LowerDFGToLLVM::compileIsObjectOrNull):
(JSC::FTL::LowerDFGToLLVM::compileIsFunction):
(JSC::FTL::LowerDFGToLLVM::compileTypeOf):
(JSC::FTL::LowerDFGToLLVM::buildTypeOf): Reusable TypeOf building for the FTL.
(JSC::FTL::LowerDFGToLLVM::isExoticForTypeof):

• ftl/FTLSwitchCase.h:

(JSC::FTL::SwitchCase::SwitchCase):

• jit/AssemblyHelpers.h:

(JSC::AssemblyHelpers::branchIfNotEqual):
(JSC::AssemblyHelpers::branchIfEqual):
(JSC::AssemblyHelpers::branchIfNumber):
(JSC::AssemblyHelpers::branchIfNotNumber):
(JSC::AssemblyHelpers::branchIfBoolean):
(JSC::AssemblyHelpers::branchIfNotBoolean):
(JSC::AssemblyHelpers::boxBooleanPayload):
(JSC::AssemblyHelpers::boxBoolean):
(JSC::AssemblyHelpers::emitTypeOf): Reusable TypeOf building for assembly JITs.

• jit/JITOperations.h:
• runtime/SmallStrings.h:

(JSC::SmallStrings::typeString):

• runtime/TypeofType.cpp: Added.

(WTF::printInternal):

• runtime/TypeofType.h: Added.
• tests/stress/type-of-functions-and-objects.js: Modified this test to give more comprehensive feedback.

File:

• trunk/Source/JavaScriptCore/runtime/SmallStrings.h (modified) (3 diffs)

trunk/Source/JavaScriptCore/runtime/SmallStrings.h

@@ -1 +1 @@
 /*
- * Copyright (C) 2008, 2009 Apple Inc. All Rights Reserved.
+ * Copyright (C) 2008, 2009, 2015 Apple Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -27 +27 @@
 #define SmallStrings_h
 
+#include "TypeofType.h"
 #include "WriteBarrier.h"
 #include <wtf/Noncopyable.h>
@@ -86 +87 @@
     JSC_COMMON_STRINGS_EACH_NAME(JSC_COMMON_STRINGS_ACCESSOR_DEFINITION)
 #undef JSC_COMMON_STRINGS_ACCESSOR_DEFINITION
+    
+    JSString* typeString(TypeofType type) const
+    {
+        switch (type) {
+        case TypeofType::Undefined:
+            return undefinedString();
+        case TypeofType::Boolean:
+            return booleanString();
+        case TypeofType::Number:
+            return numberString();
+        case TypeofType::String:
+            return stringString();
+        case TypeofType::Symbol:
+            return symbolString();
+        case TypeofType::Object:
+            return objectString();
+        case TypeofType::Function:
+            return functionString();
+        }
+        
+        RELEASE_ASSERT_NOT_REACHED();
+        return nullptr;
+    }
 
     JSString* nullObjectString() const { return m_nullObjectString; }