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
38namespace JSC { namespace FTL {
39
40using namespace DFG;
41
42MacroAssemblerCodeRef 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
109static 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
137MacroAssemblerCodeRef 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
204