commit 720e05aeb1e7c00e472d4b57f7403df43a68eaa6
author fpizlo@apple.com <fpizlo@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc> Mon Feb 17 18:59:13 2014 +0000
committer fpizlo@apple.com <fpizlo@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc> Mon Feb 17 18:59:13 2014 +0000
tree a420509b3b3656b438bd97027615b396edcb7ca3
parent 2a0879649d525ad314955422db939fdf1e810c3d

FTL OSR exit shouldn't make X86-specific assumptions
https://bugs.webkit.org/show_bug.cgi?id=128890

Reviewed by Mark Hahnenberg.

Mostly this is about not using push/pop, but instead using the more abstract pushToSave() and popToRestore() while reflecting on the stack alignment.

* assembler/MacroAssembler.h:
(JSC::MacroAssembler::pushToSaveImmediateWithoutTouchingRegisters):
(JSC::MacroAssembler::pushToSaveByteOffset):
* assembler/MacroAssemblerARM64.h:
(JSC::MacroAssemblerARM64::pushToSaveImmediateWithoutTouchingRegisters):
(JSC::MacroAssemblerARM64::pushToSaveByteOffset):
* ftl/FTLExitThunkGenerator.cpp:
(JSC::FTL::ExitThunkGenerator::emitThunk):
* ftl/FTLOSRExitCompiler.cpp:
(JSC::FTL::compileStub):
* ftl/FTLThunks.cpp:
(JSC::FTL::osrExitGenerationThunkGenerator):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@164228 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/JavaScriptCore/ftl/FTLOSRExitCompiler.cpp

diff --git a/Source/JavaScriptCore/ftl/FTLOSRExitCompiler.cpp b/Source/JavaScriptCore/ftl/FTLOSRExitCompiler.cpp
index f37a6f6..c1eb2f9 100644
--- a/Source/JavaScriptCore/ftl/FTLOSRExitCompiler.cpp
+++ b/Source/JavaScriptCore/ftl/FTLOSRExitCompiler.cpp
@@ -70,14 +70,14 @@
     char* registerScratch = bitwise_cast<char*>(scratch + exit.m_values.size());
     uint64_t* unwindScratch = bitwise_cast<uint64_t*>(registerScratch + requiredScratchMemorySizeInBytes());
     
-    // Make sure that saveAllRegisters() has a place on top of the stack to spill things. That
-    // function expects to be able to use top of stack for scratch memory.
-    jit.push(GPRInfo::regT0);
+    // Note that we come in here, the stack used to be as LLVM left it except that someone called pushToSave().
+    // We don't care about the value they saved. But, we do appreciate the fact that they did it, because we use
+    // that slot for saveAllRegisters().
+
     saveAllRegisters(jit, registerScratch);
     
     // Bring the stack back into a sane form.
-    jit.pop(GPRInfo::regT0);
-    jit.pop(GPRInfo::regT0);
+    jit.popToRestore(GPRInfo::regT0);
     
     if (vm->m_perBytecodeProfiler && codeBlock->jitCode()->dfgCommon()->compilation) {
         Profiler::Database& database = *vm->m_perBytecodeProfiler;