text: /*
   * Copyright (C) 2011-2018 Apple Inc. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
   * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
   * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
   */
  
  #include "config.h"
  #include "DFGThunks.h"
  
  #if ENABLE(DFG_JIT)
  
  #include "CCallHelpers.h"
  #include "DFGJITCode.h"
  #include "DFGOSRExit.h"
  #include "FPRInfo.h"
  #include "GPRInfo.h"
  #include "LinkBuffer.h"
  #include "MacroAssembler.h"
  #include "JSCInlines.h"
  #include "DFGOSRExitCompilerCommon.h"
  
  namespace JSC { namespace DFG {
  
  MacroAssemblerCodeRef osrExitThunkGenerator(VM* vm)
  {
      MacroAssembler jit;
      jit.probe(OSRExit::executeOSRExit, vm);
      LinkBuffer patchBuffer(jit, GLOBAL_THUNK_ID);
      return FINALIZE_CODE(patchBuffer, "DFG OSR exit thunk");
  }
  
  MacroAssemblerCodeRef osrExitGenerationThunkGenerator(VM* vm)
  {
      MacroAssembler jit;
  
      // This needs to happen before we use the scratch buffer because this function also uses the scratch buffer.
      adjustFrameAndStackInOSRExitCompilerThunk<DFG::JITCode>(jit, vm, JITCode::DFGJIT);
      
      size_t scratchSize = sizeof(EncodedJSValue) * (GPRInfo::numberOfRegisters + FPRInfo::numberOfRegisters);
      ScratchBuffer* scratchBuffer = vm->scratchBufferForSize(scratchSize);
      EncodedJSValue* buffer = static_cast<EncodedJSValue*>(scratchBuffer->dataBuffer());
      
      for (unsigned i = 0; i < GPRInfo::numberOfRegisters; ++i) {
  #if USE(JSVALUE64)
          jit.store64(GPRInfo::toRegister(i), buffer + i);
  #else
          jit.store32(GPRInfo::toRegister(i), buffer + i);
  #endif
      }
      for (unsigned i = 0; i < FPRInfo::numberOfRegisters; ++i) {
          jit.move(MacroAssembler::TrustedImmPtr(buffer + GPRInfo::numberOfRegisters + i), GPRInfo::regT0);
          jit.storeDouble(FPRInfo::toRegister(i), MacroAssembler::Address(GPRInfo::regT0));
      }
      
      // Tell GC mark phase how much of the scratch buffer is active during call.
      jit.move(MacroAssembler::TrustedImmPtr(scratchBuffer->addressOfActiveLength()), GPRInfo::regT0);
      jit.storePtr(MacroAssembler::TrustedImmPtr(scratchSize), MacroAssembler::Address(GPRInfo::regT0));
  
      // Set up one argument.
  #if CPU(X86)
      jit.poke(GPRInfo::callFrameRegister, 0);
  #else
      jit.move(GPRInfo::callFrameRegister, GPRInfo::argumentGPR0);
  #endif
  
      MacroAssembler::Call functionCall = jit.call();
  
      jit.move(MacroAssembler::TrustedImmPtr(scratchBuffer->addressOfActiveLength()), GPRInfo::regT0);
      jit.storePtr(MacroAssembler::TrustedImmPtr(nullptr), MacroAssembler::Address(GPRInfo::regT0));
  
      for (unsigned i = 0; i < FPRInfo::numberOfRegisters; ++i) {
          jit.move(MacroAssembler::TrustedImmPtr(buffer + GPRInfo::numberOfRegisters + i), GPRInfo::regT0);
          jit.loadDouble(MacroAssembler::Address(GPRInfo::regT0), FPRInfo::toRegister(i));
      }
      for (unsigned i = 0; i < GPRInfo::numberOfRegisters; ++i) {
  #if USE(JSVALUE64)
          jit.load64(buffer + i, GPRInfo::toRegister(i));
  #else
          jit.load32(buffer + i, GPRInfo::toRegister(i));
  #endif
      }
      
      jit.jump(MacroAssembler::AbsoluteAddress(&vm->osrExitJumpDestination));
      
      LinkBuffer patchBuffer(jit, GLOBAL_THUNK_ID);
      
      patchBuffer.link(functionCall, OSRExit::compileOSRExit);
      
      return FINALIZE_CODE(patchBuffer, "DFG OSR exit generation thunk");
  }
  
  MacroAssemblerCodeRef osrEntryThunkGenerator(VM* vm)
  {
      AssemblyHelpers jit(nullptr);
  
      // We get passed the address of a scratch buffer. The first 8-byte slot of the buffer
      // is the frame size. The second 8-byte slot is the pointer to where we are supposed to
      // jump. The remaining bytes are the new call frame header followed by the locals.
      
      ptrdiff_t offsetOfFrameSize = 0; // This is the DFG frame count.
      ptrdiff_t offsetOfTargetPC = offsetOfFrameSize + sizeof(EncodedJSValue);
      ptrdiff_t offsetOfPayload = offsetOfTargetPC + sizeof(EncodedJSValue);
      ptrdiff_t offsetOfLocals = offsetOfPayload + sizeof(Register) * CallFrame::headerSizeInRegisters;
      
      jit.move(GPRInfo::returnValueGPR2, GPRInfo::regT0);
      jit.loadPtr(MacroAssembler::Address(GPRInfo::regT0, offsetOfFrameSize), GPRInfo::regT1); // Load the frame size.
      jit.negPtr(GPRInfo::regT1, GPRInfo::regT2);
      jit.getEffectiveAddress(MacroAssembler::BaseIndex(GPRInfo::callFrameRegister, GPRInfo::regT2, MacroAssembler::TimesEight), MacroAssembler::stackPointerRegister);
      
      MacroAssembler::Label loop = jit.label();
      jit.subPtr(MacroAssembler::TrustedImm32(1), GPRInfo::regT1);
      jit.negPtr(GPRInfo::regT1, GPRInfo::regT4);
      jit.load32(MacroAssembler::BaseIndex(GPRInfo::regT0, GPRInfo::regT1, MacroAssembler::TimesEight, offsetOfLocals), GPRInfo::regT2);
      jit.load32(MacroAssembler::BaseIndex(GPRInfo::regT0, GPRInfo::regT1, MacroAssembler::TimesEight, offsetOfLocals + sizeof(int32_t)), GPRInfo::regT3);
      jit.store32(GPRInfo::regT2, MacroAssembler::BaseIndex(GPRInfo::callFrameRegister, GPRInfo::regT4, MacroAssembler::TimesEight, -static_cast<intptr_t>(sizeof(Register))));
      jit.store32(GPRInfo::regT3, MacroAssembler::BaseIndex(GPRInfo::callFrameRegister, GPRInfo::regT4, MacroAssembler::TimesEight, -static_cast<intptr_t>(sizeof(Register)) + static_cast<intptr_t>(sizeof(int32_t))));
      jit.branchPtr(MacroAssembler::NotEqual, GPRInfo::regT1, MacroAssembler::TrustedImmPtr(bitwise_cast<void*>(-static_cast<intptr_t>(CallFrame::headerSizeInRegisters)))).linkTo(loop, &jit);
      
      jit.loadPtr(MacroAssembler::Address(GPRInfo::regT0, offsetOfTargetPC), GPRInfo::regT1);
      MacroAssembler::Jump ok = jit.branchPtr(MacroAssembler::Above, GPRInfo::regT1, MacroAssembler::TrustedImmPtr(bitwise_cast<void*>(static_cast<intptr_t>(1000))));
      jit.abortWithReason(DFGUnreasonableOSREntryJumpDestination);
  
      ok.link(&jit);
      jit.restoreCalleeSavesFromEntryFrameCalleeSavesBuffer(vm->topEntryFrame);
      jit.emitMaterializeTagCheckRegisters();
  
      jit.jump(GPRInfo::regT1);
      
      LinkBuffer patchBuffer(jit, GLOBAL_THUNK_ID);
      return FINALIZE_CODE(patchBuffer, "DFG OSR entry thunk");
  }
  
  } } // namespace JSC::DFG
  
  #endif // ENABLE(DFG_JIT)
  