ftl/FTLThunks.cpp

   1 /*
   2  * Copyright (C) 2013 Apple Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "config.h"
  27 #include "FTLThunks.h"
  28
  29 #if ENABLE(FTL_JIT)
  30
  31 #include "AssemblyHelpers.h"
  32 #include "FPRInfo.h"
  33 #include "FTLOSRExitCompiler.h"
  34 #include "FTLSaveRestore.h"
  35 #include "GPRInfo.h"
  36 #include "LinkBuffer.h"
  37
  38 namespace JSC { namespace FTL {
  39
  40 using namespace DFG;
  41
  42 MacroAssemblerCodeRef osrExitGenerationThunkGenerator(VM* vm)
  43 {
  44     AssemblyHelpers jit(vm, 0);
  45
  46     // Note that the "return address" will be the OSR exit ID.
  47
  48     ptrdiff_t stackMisalignment = MacroAssembler::pushToSaveByteOffset();
  49
  50     // Pretend that we're a C call frame.
  51     jit.pushToSave(MacroAssembler::framePointerRegister);
  52     jit.move(MacroAssembler::stackPointerRegister, MacroAssembler::framePointerRegister);
  53     stackMisalignment += MacroAssembler::pushToSaveByteOffset();
  54
  55     // Now create ourselves enough stack space to give saveAllRegisters() a scratch slot.
  56     unsigned numberOfRequiredPops = 0;
  57     do {
  58         jit.pushToSave(GPRInfo::regT0);
  59         stackMisalignment += MacroAssembler::pushToSaveByteOffset();
  60         numberOfRequiredPops++;
  61     } while (stackMisalignment % stackAlignmentBytes());
  62
  63     ScratchBuffer* scratchBuffer = vm->scratchBufferForSize(requiredScratchMemorySizeInBytes());
  64     char* buffer = static_cast<char*>(scratchBuffer->dataBuffer());
  65
  66     saveAllRegisters(jit, buffer);
  67
  68     // Tell GC mark phase how much of the scratch buffer is active during call.
  69     jit.move(MacroAssembler::TrustedImmPtr(scratchBuffer->activeLengthPtr()), GPRInfo::nonArgGPR1);
  70     jit.storePtr(MacroAssembler::TrustedImmPtr(requiredScratchMemorySizeInBytes()), GPRInfo::nonArgGPR1);
  71
  72     jit.loadPtr(GPRInfo::callFrameRegister, GPRInfo::argumentGPR0);
  73     jit.peek(
  74         GPRInfo::argumentGPR1,
  75         (stackMisalignment - MacroAssembler::pushToSaveByteOffset()) / sizeof(void*));
  76     MacroAssembler::Call functionCall = jit.call();
  77
  78     // At this point we want to make a tail call to what was returned to us in the
  79     // returnValueGPR. But at the same time as we do this, we must restore all registers.
  80     // The way we will accomplish this is by arranging to have the tail call target in the
  81     // return address "slot" (be it a register or the stack).
  82
  83     jit.move(GPRInfo::returnValueGPR, GPRInfo::regT0);
  84
  85     // Make sure we tell the GC that we're not using the scratch buffer anymore.
  86     jit.move(MacroAssembler::TrustedImmPtr(scratchBuffer->activeLengthPtr()), GPRInfo::regT1);
  87     jit.storePtr(MacroAssembler::TrustedImmPtr(0), GPRInfo::regT1);
  88
  89     // Prepare for tail call.
  90     while (numberOfRequiredPops--)
  91         jit.popToRestore(GPRInfo::regT1);
  92     jit.popToRestore(MacroAssembler::framePointerRegister);
  93
  94     // At this point we're sitting on the return address - so if we did a jump right now, the
  95     // tail-callee would be happy. Instead we'll stash the callee in the return address and then
  96     // restore all registers.
  97
  98     jit.restoreReturnAddressBeforeReturn(GPRInfo::regT0);
  99
 100     restoreAllRegisters(jit, buffer);
 101
 102     jit.ret();
 103
 104     LinkBuffer patchBuffer(*vm, jit, GLOBAL_THUNK_ID);
 105     patchBuffer.link(functionCall, compileFTLOSRExit);
 106     return FINALIZE_CODE(patchBuffer, ("FTL OSR exit generation thunk"));
 107 }
 108
 109 static void registerClobberCheck(AssemblyHelpers& jit, RegisterSet dontClobber)
 110 {
 111     if (!Options::clobberAllRegsInFTLICSlowPath())
 112         return;
 113
 114     RegisterSet clobber = RegisterSet::allRegisters();
 115     clobber.exclude(RegisterSet::reservedHardwareRegisters());
 116     clobber.exclude(RegisterSet::stackRegisters());
 117     clobber.exclude(RegisterSet::calleeSaveRegisters());
 118     clobber.exclude(dontClobber);
 119
 120     GPRReg someGPR;
 121     for (Reg reg = Reg::first(); reg <= Reg::last(); reg = reg.next()) {
 122         if (!clobber.get(reg) || !reg.isGPR())
 123             continue;
 124
 125         jit.move(AssemblyHelpers::TrustedImm32(0x1337beef), reg.gpr());
 126         someGPR = reg.gpr();
 127     }
 128
 129     for (Reg reg = Reg::first(); reg <= Reg::last(); reg = reg.next()) {
 130         if (!clobber.get(reg) || !reg.isFPR())
 131             continue;
 132
 133         jit.move64ToDouble(someGPR, reg.fpr());
 134     }
 135 }
 136
 137 MacroAssemblerCodeRef slowPathCallThunkGenerator(VM& vm, const SlowPathCallKey& key)
 138 {
 139     AssemblyHelpers jit(&vm, 0);
 140
 141     // We want to save the given registers at the given offset, then we want to save the
 142     // old return address somewhere past that offset, and then finally we want to make the
 143     // call.
 144
 145     size_t currentOffset = key.offset() + sizeof(void*);
 146
 147 #if CPU(X86) || CPU(X86_64)
 148     currentOffset += sizeof(void*);
 149 #endif
 150
 151     for (MacroAssembler::RegisterID reg = MacroAssembler::firstRegister(); reg <= MacroAssembler::lastRegister(); reg = static_cast<MacroAssembler::RegisterID>(reg + 1)) {
 152         if (!key.usedRegisters().get(reg))
 153             continue;
 154         jit.storePtr(reg, AssemblyHelpers::Address(MacroAssembler::stackPointerRegister, currentOffset));
 155         currentOffset += sizeof(void*);
 156     }
 157
 158     for (MacroAssembler::FPRegisterID reg = MacroAssembler::firstFPRegister(); reg <= MacroAssembler::lastFPRegister(); reg = static_cast<MacroAssembler::FPRegisterID>(reg + 1)) {
 159         if (!key.usedRegisters().get(reg))
 160             continue;
 161         jit.storeDouble(reg, AssemblyHelpers::Address(MacroAssembler::stackPointerRegister, currentOffset));
 162         currentOffset += sizeof(double);
 163     }
 164
 165     jit.preserveReturnAddressAfterCall(GPRInfo::nonArgGPR0);
 166     jit.storePtr(GPRInfo::nonArgGPR0, AssemblyHelpers::Address(MacroAssembler::stackPointerRegister, key.offset()));
 167
 168     registerClobberCheck(jit, key.argumentRegisters());
 169
 170     AssemblyHelpers::Call call = jit.call();
 171
 172     jit.loadPtr(AssemblyHelpers::Address(MacroAssembler::stackPointerRegister, key.offset()), GPRInfo::nonPreservedNonReturnGPR);
 173     jit.restoreReturnAddressBeforeReturn(GPRInfo::nonPreservedNonReturnGPR);
 174
 175     for (MacroAssembler::FPRegisterID reg = MacroAssembler::lastFPRegister(); ; reg = static_cast<MacroAssembler::FPRegisterID>(reg - 1)) {
 176         if (key.usedRegisters().get(reg)) {
 177             currentOffset -= sizeof(double);
 178             jit.loadDouble(AssemblyHelpers::Address(MacroAssembler::stackPointerRegister, currentOffset), reg);
 179         }
 180         if (reg == MacroAssembler::firstFPRegister())
 181             break;
 182     }
 183
 184     for (MacroAssembler::RegisterID reg = MacroAssembler::lastRegister(); ; reg = static_cast<MacroAssembler::RegisterID>(reg - 1)) {
 185         if (key.usedRegisters().get(reg)) {
 186             currentOffset -= sizeof(void*);
 187             jit.loadPtr(AssemblyHelpers::Address(MacroAssembler::stackPointerRegister, currentOffset), reg);
 188         }
 189         if (reg == MacroAssembler::firstRegister())
 190             break;
 191     }
 192
 193     jit.ret();
 194
 195     LinkBuffer patchBuffer(vm, jit, GLOBAL_THUNK_ID);
 196     patchBuffer.link(call, FunctionPtr(key.callTarget()));
 197     return FINALIZE_CODE(patchBuffer, ("FTL slow path call thunk for %s", toCString(key).data()));
 198 }
 199
 200 } } // namespace JSC::FTL
 201
 202 #endif // ENABLE(FTL_JIT)
 203