Changeset 134332 in webkit for trunk/Source/JavaScriptCore/assembler/RepatchBuffer.h

Timestamp:

Nov 12, 2012, 5:55:42 PM (13 years ago)

Author:

[email protected]

Message:

Patching of jumps to stubs should use jump replacement rather than branch destination overwrite
​https://bugs.webkit.org/show_bug.cgi?id=101909

Reviewed by Geoffrey Garen.

This saves a few instructions in inline cases, on those architectures where it is
easy to figure out where to put the jump replacement. Sub-1% speed-up across the
board.

• assembler/MacroAssemblerARMv7.h:

(MacroAssemblerARMv7):
(JSC::MacroAssemblerARMv7::canJumpReplacePatchableBranchPtrWithPatch):
(JSC::MacroAssemblerARMv7::startOfPatchableBranchPtrWithPatch):
(JSC::MacroAssemblerARMv7::revertJumpReplacementToPatchableBranchPtrWithPatch):

• assembler/MacroAssemblerX86.h:

(JSC::MacroAssemblerX86::canJumpReplacePatchableBranchPtrWithPatch):
(MacroAssemblerX86):
(JSC::MacroAssemblerX86::startOfPatchableBranchPtrWithPatch):
(JSC::MacroAssemblerX86::revertJumpReplacementToPatchableBranchPtrWithPatch):

• assembler/MacroAssemblerX86_64.h:

(JSC::MacroAssemblerX86_64::canJumpReplacePatchableBranchPtrWithPatch):
(MacroAssemblerX86_64):
(JSC::MacroAssemblerX86_64::startOfPatchableBranchPtrWithPatch):
(JSC::MacroAssemblerX86_64::revertJumpReplacementToPatchableBranchPtrWithPatch):

• assembler/RepatchBuffer.h:

(JSC::RepatchBuffer::startOfPatchableBranchPtrWithPatch):
(RepatchBuffer):
(JSC::RepatchBuffer::replaceWithJump):
(JSC::RepatchBuffer::revertJumpReplacementToPatchableBranchPtrWithPatch):

• assembler/X86Assembler.h:

(X86Assembler):
(JSC::X86Assembler::revertJumpTo_movq_i64r):
(JSC::X86Assembler::revertJumpTo_cmpl_im_force32):
(X86InstructionFormatter):

• bytecode/StructureStubInfo.h:
• dfg/DFGRepatch.cpp:

(JSC::DFG::replaceWithJump):
(DFG):
(JSC::DFG::tryCacheGetByID):
(JSC::DFG::tryBuildGetByIDList):
(JSC::DFG::tryBuildGetByIDProtoList):
(JSC::DFG::tryCachePutByID):
(JSC::DFG::dfgResetGetByID):
(JSC::DFG::dfgResetPutByID):

File:

• trunk/Source/JavaScriptCore/assembler/RepatchBuffer.h (modified) (1 diff)

trunk/Source/JavaScriptCore/assembler/RepatchBuffer.h

@@ -142 +142 @@
     }
 
+    static CodeLocationLabel startOfPatchableBranchPtrWithPatch(CodeLocationDataLabelPtr label)
+    {
+        return MacroAssembler::startOfPatchableBranchPtrWithPatch(label);
+    }
+    
+    void replaceWithJump(CodeLocationLabel instructionStart, CodeLocationLabel destination)
+    {
+        MacroAssembler::replaceWithJump(instructionStart, destination);
+    }
+    
+    // This is a *bit* of a silly API, since we currently always also repatch the
+    // immediate after calling this. But I'm fine with that, since this just feels
+    // less yucky.
+    void revertJumpReplacementToPatchableBranchPtrWithPatch(CodeLocationLabel instructionStart, MacroAssembler::Address address, void* value)
+    {
+        MacroAssembler::revertJumpReplacementToPatchableBranchPtrWithPatch(instructionStart, address, value);
+    }
+
 private:
     void* m_start;