1 files changed, 92 insertions, 8 deletions

diff --git a/Source/JavaScriptCore/dfg/DFGOSRExitCompilerCommon.h b/Source/JavaScriptCore/dfg/DFGOSRExitCompilerCommon.h
index 8ceb8b6d4..8d278ce71 100644
--- a/Source/JavaScriptCore/dfg/DFGOSRExitCompilerCommon.h
+++ b/Source/JavaScriptCore/dfg/DFGOSRExitCompilerCommon.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2013 Apple Inc. All rights reserved.
+ * Copyright (C) 2013, 2015 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -23,15 +23,16 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
  */
 
-#ifndef DFGOSRExitCompilerCommon_h
-#define DFGOSRExitCompilerCommon_h
-
-#include <wtf/Platform.h>
+#pragma once
 
 #if ENABLE(DFG_JIT)
 
 #include "CCallHelpers.h"
 #include "DFGOSRExit.h"
+#include "DFGCommonData.h"
+#include "DFGJITCode.h"
+#include "FTLJITCode.h"
+#include "RegisterSet.h"
 
 namespace JSC { namespace DFG {
 
@@ -39,9 +40,92 @@ void handleExitCounts(CCallHelpers&, const OSRExitBase&);
 void reifyInlinedCallFrames(CCallHelpers&, const OSRExitBase&);
 void adjustAndJumpToTarget(CCallHelpers&, const OSRExitBase&);
 
-} } // namespace JSC::DFG
+template <typename JITCodeType>
+void adjustFrameAndStackInOSRExitCompilerThunk(MacroAssembler& jit, VM* vm, JITCode::JITType jitType)
+{
+    ASSERT(jitType == JITCode::DFGJIT || jitType == JITCode::FTLJIT);
 
-#endif // ENABLE(DFG_JIT)
+    bool isFTLOSRExit = jitType == JITCode::FTLJIT;
+    RegisterSet registersToPreserve;
+    registersToPreserve.set(GPRInfo::regT0);
+    if (isFTLOSRExit) {
+        // FTL can use the scratch registers for values. The code below uses
+        // the scratch registers. We need to preserve them before doing anything.
+        registersToPreserve.merge(RegisterSet::macroScratchRegisters());
+    }
+
+    size_t scratchSize = sizeof(void*) * registersToPreserve.numberOfSetGPRs();
+    if (isFTLOSRExit)
+        scratchSize += sizeof(void*);
+
+    ScratchBuffer* scratchBuffer = vm->scratchBufferForSize(scratchSize);
+    char* buffer = static_cast<char*>(scratchBuffer->dataBuffer());
+
+    jit.pushToSave(GPRInfo::regT1);
+    jit.move(MacroAssembler::TrustedImmPtr(buffer), GPRInfo::regT1);
+
+    unsigned storeOffset = 0;
+    registersToPreserve.forEach([&](Reg reg) {
+        jit.storePtr(reg.gpr(), MacroAssembler::Address(GPRInfo::regT1, storeOffset));
+        storeOffset += sizeof(void*);
+    });
+
+    if (isFTLOSRExit) {
+        // FTL OSRExits are entered via the code FTLExitThunkGenerator emits which does
+        // pushToSaveImmediateWithoutTouchRegisters with the OSR exit index. We need to load
+        // that top value and then push it back when we reset our SP.
+        jit.loadPtr(MacroAssembler::Address(MacroAssembler::stackPointerRegister, MacroAssembler::pushToSaveByteOffset()), GPRInfo::regT0);
+        jit.storePtr(GPRInfo::regT0, MacroAssembler::Address(GPRInfo::regT1, registersToPreserve.numberOfSetGPRs() * sizeof(void*)));
+    }
+    jit.popToRestore(GPRInfo::regT1);
 
-#endif // DFGOSRExitCompilerCommon_h
+    // We need to reset FP in the case of an exception.
+    jit.loadPtr(vm->addressOfCallFrameForCatch(), GPRInfo::regT0);
+    MacroAssembler::Jump didNotHaveException = jit.branchTestPtr(MacroAssembler::Zero, GPRInfo::regT0);
+    jit.move(GPRInfo::regT0, GPRInfo::callFrameRegister);
+    didNotHaveException.link(&jit);
+    // We need to make sure SP is correct in case of an exception.
+    jit.loadPtr(MacroAssembler::Address(GPRInfo::callFrameRegister, CallFrameSlot::codeBlock * static_cast<int>(sizeof(Register))), GPRInfo::regT0);
+    jit.loadPtr(MacroAssembler::Address(GPRInfo::regT0, CodeBlock::jitCodeOffset()), GPRInfo::regT0);
+    jit.addPtr(MacroAssembler::TrustedImm32(JITCodeType::commonDataOffset()), GPRInfo::regT0);
+    jit.load32(MacroAssembler::Address(GPRInfo::regT0, CommonData::frameRegisterCountOffset()), GPRInfo::regT0);
+    // This does virtualRegisterForLocal(frameRegisterCount - 1)*sizeof(Register) where:
+    // virtualRegisterForLocal(frameRegisterCount - 1)
+    //     = VirtualRegister::localToOperand(frameRegisterCount - 1)
+    //     = -1 - (frameRegisterCount - 1)
+    //     = -frameRegisterCount
+    jit.neg32(GPRInfo::regT0);
+    jit.mul32(MacroAssembler::TrustedImm32(sizeof(Register)), GPRInfo::regT0, GPRInfo::regT0);
+#if USE(JSVALUE64)
+    jit.signExtend32ToPtr(GPRInfo::regT0, GPRInfo::regT0);
+#endif
+    jit.addPtr(GPRInfo::callFrameRegister, GPRInfo::regT0);
+    jit.move(GPRInfo::regT0, MacroAssembler::stackPointerRegister);
 
+    if (isFTLOSRExit) {
+        // Leave space for saving the OSR Exit Index.
+        jit.subPtr(MacroAssembler::TrustedImm32(MacroAssembler::pushToSaveByteOffset()), MacroAssembler::stackPointerRegister);
+    }
+    jit.pushToSave(GPRInfo::regT1);
+
+    jit.move(MacroAssembler::TrustedImmPtr(buffer), GPRInfo::regT1);
+    if (isFTLOSRExit) {
+        // FTL OSRExits are entered via FTLExitThunkGenerator code with does
+        // pushToSaveImmediateWithoutTouchRegisters. We need to load that top
+        // register and then store it back when we have our SP back to a safe value.
+        jit.loadPtr(MacroAssembler::Address(GPRInfo::regT1, registersToPreserve.numberOfSetGPRs() * sizeof(void*)), GPRInfo::regT0);
+        jit.storePtr(GPRInfo::regT0, MacroAssembler::Address(MacroAssembler::stackPointerRegister, MacroAssembler::pushToSaveByteOffset()));
+    }
+
+    unsigned loadOffset = 0;
+    registersToPreserve.forEach([&](Reg reg) {
+        jit.loadPtr(MacroAssembler::Address(GPRInfo::regT1, loadOffset), reg.gpr());
+        loadOffset += sizeof(void*);
+    });
+    jit.popToRestore(GPRInfo::regT1);
+}
+
+
+} } // namespace JSC::DFG
+
+#endif // ENABLE(DFG_JIT)