Changeset 58286 in webkit for trunk/JavaScriptCore/jit/JITStubs.cpp

Timestamp:

Apr 26, 2010, 9:22:46 PM (15 years ago)

Author:

[email protected]

Message:

2010-04-26 Oliver Hunt <​[email protected]>

Reviewed by Gavin Barraclough.

Need to support more efficient dispatch of lightweight builtins
​https://bugs.webkit.org/show_bug.cgi?id=38155

The problem with calling lightweight builtins is that marshalling
the call from the nitro calling convention to the system calling
convention is very expensive relative to the cost of the actually
evaluating the function. To work around this problem this patch
adds the ability to define a custom thunk for a builtin.

This allows us to use high performance custom implementations of
the common and sensible versions of simple builtins. This patch
includes a simple (use of which is currently hardcoded) thunk for
charCodeAt.

This adds a JSInterfaceJIT subclass called SpecializedThunkJIT
that has helper functions to remove (or at least reduce) the need
to have separate thunk implementations for each JSValue encoding.

• GNUmakefile.am:
• JavaScriptCore.pro:
• JavaScriptCore.vcproj/JavaScriptCore/JavaScriptCore.vcproj:
• JavaScriptCore.xcodeproj/project.pbxproj: Many project file updates

• create_hash_table: Add thunk generation callbacks to the hash tables, currently we hardcode the script to only support charCodeAt

• jit/JITStubCall.h:
• jit/JITStubs.cpp: (JSC::JITThunks::~JITThunks): (JSC::JITThunks::specializedThunk):
• jit/JITStubs.h:
• jit/SpecializedThunkJIT.h: Added. (JSC::SpecializedThunkJIT::SpecializedThunkJIT): (JSC::SpecializedThunkJIT::loadCellArgument): (JSC::SpecializedThunkJIT::loadJSStringArgument): (JSC::SpecializedThunkJIT::loadInt32Argument): (JSC::SpecializedThunkJIT::appendFailure): (JSC::SpecializedThunkJIT::returnInt32): (JSC::SpecializedThunkJIT::finalize): (JSC::SpecializedThunkJIT::argumentToVirtualRegister): (JSC::SpecializedThunkJIT::tagReturnAsInt32):
• jit/ThunkGenerators.cpp: Added. (JSC::ThunkHelpers::stringImplDataOffset): (JSC::ThunkHelpers::jsStringLengthOffset): (JSC::ThunkHelpers::jsStringValueOffset): (JSC::charCodeAtThunkGenerator):
• jit/ThunkGenerators.h: Added.
• runtime/Executable.h: (JSC::NativeExecutable::NativeExecutable):
• runtime/JSFunction.cpp: (JSC::JSFunction::JSFunction):
• runtime/JSFunction.h:
• runtime/JSGlobalData.h: (JSC::JSGlobalData::getThunk):
• runtime/JSString.h: (JSC::):
• runtime/JSValue.h: Protect some of the JSVALUE32 and JSVALUE32_64 only constants and function behind appropriate USE() guards to make it harder to use the wrong flags for the target build.
• runtime/Lookup.cpp: (JSC::HashTable::createTable): (JSC::setUpStaticFunctionSlot):
• runtime/Lookup.h: (JSC::HashEntry::initialize): (JSC::HashEntry::generator): (JSC::HashEntry::): Make the lookup tables use a specialized thunkGenerator if present
• wtf/text/StringImpl.h:

2010-04-26 Oliver Hunt <​[email protected]>

Reviewed by Gavin Barraclough.

Need to support more efficient dispatch of lightweight builtins
​https://bugs.webkit.org/show_bug.cgi?id=38155

Update bindings generation to include new thunk generator field
in the property map hash tables.

• bindings/scripts/CodeGeneratorJS.pm:

File:

• trunk/JavaScriptCore/jit/JITStubs.cpp (modified) (2 diffs)

trunk/JavaScriptCore/jit/JITStubs.cpp

@@ -837 +837 @@
 
 #endif
+}
+
+JITThunks::~JITThunks()
+{
 }
 
@@ -3304 +3308 @@
 }
 
+NativeExecutable* JITThunks::specializedThunk(JSGlobalData* globalData, ThunkGenerator generator)
+{
+    std::pair<ThunkMap::iterator, bool> entry = m_thunkMap.add(generator, 0);
+    if (!entry.second)
+        return entry.first->second.get();
+    entry.first->second = generator(globalData, m_executablePool.get());
+    return entry.first->second.get();
+}
+
 } // namespace JSC