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):
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@134332 268f45cc-cd09-0410-ab3c-d52691b4dbfc
diff --git a/Source/JavaScriptCore/assembler/MacroAssemblerX86.h b/Source/JavaScriptCore/assembler/MacroAssemblerX86.h
index 8fd3146..123d657 100644
--- a/Source/JavaScriptCore/assembler/MacroAssemblerX86.h
+++ b/Source/JavaScriptCore/assembler/MacroAssemblerX86.h
@@ -253,6 +253,25 @@
return FunctionPtr(reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(call.dataLocation()) + offset));
}
+ static bool canJumpReplacePatchableBranchPtrWithPatch() { return true; }
+
+ static CodeLocationLabel startOfPatchableBranchPtrWithPatch(CodeLocationDataLabelPtr label)
+ {
+ const int opcodeBytes = 1;
+ const int modRMBytes = 1;
+ const int offsetBytes = 0;
+ const int immediateBytes = 4;
+ const int totalBytes = opcodeBytes + modRMBytes + offsetBytes + immediateBytes;
+ ASSERT(totalBytes >= maxJumpReplacementSize());
+ return label.labelAtOffset(-totalBytes);
+ }
+
+ static void revertJumpReplacementToPatchableBranchPtrWithPatch(CodeLocationLabel instructionStart, Address address, void* initialValue)
+ {
+ ASSERT(!address.offset);
+ X86Assembler::revertJumpTo_cmpl_im_force32(instructionStart.executableAddress(), reinterpret_cast<intptr_t>(initialValue), 0, address.base);
+ }
+
private:
friend class LinkBuffer;
friend class RepatchBuffer;
