static void slowPathFor(
CCallHelpers& jit, VM* vm, Sprt_JITOperation_ECli slowPathFunction)
{
jit.emitFunctionPrologue();
jit.storePtr(GPRInfo::callFrameRegister, &vm->topCallFrame);
#if OS(WINDOWS) && CPU(X86_64)
// Windows X86_64 needs some space pointed to by arg0 for return types larger than 64 bits.
// Other argument values are shift by 1. Use space on the stack for our two return values.
// Moving the stack down maxFrameExtentForSlowPathCall bytes gives us room for our 3 arguments
// and space for the 16 byte return area.
jit.addPtr(CCallHelpers::TrustedImm32(-maxFrameExtentForSlowPathCall), CCallHelpers::stackPointerRegister);
jit.move(GPRInfo::regT2, GPRInfo::argumentGPR2);
jit.addPtr(CCallHelpers::TrustedImm32(32), CCallHelpers::stackPointerRegister, GPRInfo::argumentGPR0);
jit.move(GPRInfo::callFrameRegister, GPRInfo::argumentGPR1);
jit.move(CCallHelpers::TrustedImmPtr(bitwise_cast<void*>(slowPathFunction)), GPRInfo::nonArgGPR0);
emitPointerValidation(jit, GPRInfo::nonArgGPR0);
jit.call(GPRInfo::nonArgGPR0);
jit.loadPtr(CCallHelpers::Address(GPRInfo::returnValueGPR, 8), GPRInfo::returnValueGPR2);
jit.loadPtr(CCallHelpers::Address(GPRInfo::returnValueGPR), GPRInfo::returnValueGPR);
jit.addPtr(CCallHelpers::TrustedImm32(maxFrameExtentForSlowPathCall), CCallHelpers::stackPointerRegister);
#else
if (maxFrameExtentForSlowPathCall)
jit.addPtr(CCallHelpers::TrustedImm32(-maxFrameExtentForSlowPathCall), CCallHelpers::stackPointerRegister);
jit.setupArgumentsWithExecState(GPRInfo::regT2);
jit.move(CCallHelpers::TrustedImmPtr(bitwise_cast<void*>(slowPathFunction)), GPRInfo::nonArgGPR0);
emitPointerValidation(jit, GPRInfo::nonArgGPR0);
jit.call(GPRInfo::nonArgGPR0);
if (maxFrameExtentForSlowPathCall)
jit.addPtr(CCallHelpers::TrustedImm32(maxFrameExtentForSlowPathCall), CCallHelpers::stackPointerRegister);
#endif
// This slow call will return the address of one of the following:
// 1) Exception throwing thunk.
// 2) Host call return value returner thingy.
// 3) The function to call.
// The second return value GPR will hold a non-zero value for tail calls.
emitPointerValidation(jit, GPRInfo::returnValueGPR);
jit.emitFunctionEpilogue();
RELEASE_ASSERT(reinterpret_cast<void*>(KeepTheFrame) == reinterpret_cast<void*>(0));
CCallHelpers::Jump doNotTrash = jit.branchTestPtr(CCallHelpers::Zero, GPRInfo::returnValueGPR2);
jit.preserveReturnAddressAfterCall(GPRInfo::nonPreservedNonReturnGPR);
jit.prepareForTailCallSlow(GPRInfo::returnValueGPR);
doNotTrash.link(&jit);
jit.jump(GPRInfo::returnValueGPR);
}
static void slowPathFor(
CCallHelpers& jit, VM* vm, P_JITOperation_E slowPathFunction)
{
jit.emitFunctionPrologue();
jit.storePtr(GPRInfo::callFrameRegister, &vm->topCallFrame);
if (maxFrameExtentForSlowPathCall)
jit.addPtr(CCallHelpers::TrustedImm32(-maxFrameExtentForSlowPathCall), CCallHelpers::stackPointerRegister);
jit.setupArgumentsExecState();
jit.move(CCallHelpers::TrustedImmPtr(bitwise_cast<void*>(slowPathFunction)), GPRInfo::nonArgGPR0);
emitPointerValidation(jit, GPRInfo::nonArgGPR0);
jit.call(GPRInfo::nonArgGPR0);
if (maxFrameExtentForSlowPathCall)
jit.addPtr(CCallHelpers::TrustedImm32(maxFrameExtentForSlowPathCall), CCallHelpers::stackPointerRegister);
// This slow call will return the address of one of the following:
// 1) Exception throwing thunk.
// 2) Host call return value returner thingy.
// 3) The function to call.
emitPointerValidation(jit, GPRInfo::returnValueGPR);
jit.emitFunctionEpilogue();
jit.jump(GPRInfo::returnValueGPR);
}
void generate(Code& code, CCallHelpers& jit)
{
TimingScope timingScope("Air::generate");
// We don't expect the incoming code to have predecessors computed.
code.resetReachability();
if (shouldValidateIR())
validate(code);
// If we're doing super verbose dumping, the phase scope of any phase will already do a dump.
if (shouldDumpIR() && !shouldDumpIRAtEachPhase()) {
dataLog("Initial air:\n");
dataLog(code);
}
// This is where we run our optimizations and transformations.
// FIXME: Add Air optimizations.
// https://bugs.webkit.org/show_bug.cgi?id=150456
eliminateDeadCode(code);
// This is where we would have a real register allocator. Then, we could use spillEverything()
// in place of the register allocator only for testing.
// FIXME: https://bugs.webkit.org/show_bug.cgi?id=150457
spillEverything(code);
// Prior to this point the prologue and epilogue is implicit. This makes it explicit. It also
// does things like identify which callee-saves we're using and saves them.
handleCalleeSaves(code);
// This turns all Stack and CallArg Args into Addr args that use the frame pointer. It does
// this by first-fit allocating stack slots. It should be pretty darn close to optimal, so we
// shouldn't have to worry about this very much.
allocateStack(code);
// If we coalesced moves then we can unbreak critical edges. This is the main reason for this
// phase.
simplifyCFG(code);
// FIXME: We should really have a code layout optimization here.
// https://bugs.webkit.org/show_bug.cgi?id=150478
reportUsedRegisters(code);
if (shouldValidateIR())
validate(code);
// Do a final dump of Air. Note that we have to do this even if we are doing per-phase dumping,
// since the final generation is not a phase.
if (shouldDumpIR()) {
dataLog("Air after ", code.lastPhaseName(), ", before generation:\n");
dataLog(code);
}
TimingScope codeGenTimingScope("Air::generate backend");
// And now, we generate code.
jit.emitFunctionPrologue();
jit.addPtr(CCallHelpers::TrustedImm32(-code.frameSize()), MacroAssembler::stackPointerRegister);
GenerationContext context;
context.code = &code;
IndexMap<BasicBlock, CCallHelpers::Label> blockLabels(code.size());
IndexMap<BasicBlock, CCallHelpers::JumpList> blockJumps(code.size());
auto link = [&] (CCallHelpers::Jump jump, BasicBlock* target) {
if (blockLabels[target].isSet()) {
jump.linkTo(blockLabels[target], &jit);
return;
}
blockJumps[target].append(jump);
};
for (BasicBlock* block : code) {
blockJumps[block].link(&jit);
ASSERT(block->size() >= 1);
for (unsigned i = 0; i < block->size() - 1; ++i) {
CCallHelpers::Jump jump = block->at(i).generate(jit, context);
ASSERT_UNUSED(jump, !jump.isSet());
}
if (block->last().opcode == Jump
&& block->successorBlock(0) == code.findNextBlock(block))
continue;
if (block->last().opcode == Ret) {
// We currently don't represent the full prologue/epilogue in Air, so we need to
// have this override.
jit.emitFunctionEpilogue();
jit.ret();
continue;
}
CCallHelpers::Jump jump = block->last().generate(jit, context);
for (Inst& inst : *block)
jump = inst.generate(jit, context);
switch (block->numSuccessors()) {
case 0:
ASSERT(!jump.isSet());
break;
case 1:
link(jump, block->successorBlock(0));
break;
case 2:
link(jump, block->successorBlock(0));
if (block->successorBlock(1) != code.findNextBlock(block))
link(jit.jump(), block->successorBlock(1));
break;
default:
RELEASE_ASSERT_NOT_REACHED();
break;
}
}
for (auto& latePath : context.latePaths)
latePath->run(jit, context);
}
void generate(Code& code, CCallHelpers& jit)
{
TimingScope timingScope("Air::generate");
DisallowMacroScratchRegisterUsage disallowScratch(jit);
// And now, we generate code.
jit.emitFunctionPrologue();
if (code.frameSize())
jit.addPtr(CCallHelpers::TrustedImm32(-code.frameSize()), MacroAssembler::stackPointerRegister);
GenerationContext context;
context.code = &code;
IndexMap<BasicBlock, CCallHelpers::Label> blockLabels(code.size());
IndexMap<BasicBlock, CCallHelpers::JumpList> blockJumps(code.size());
auto link = [&] (CCallHelpers::Jump jump, BasicBlock* target) {
if (blockLabels[target].isSet()) {
jump.linkTo(blockLabels[target], &jit);
return;
}
blockJumps[target].append(jump);
};
for (BasicBlock* block : code) {
blockJumps[block].link(&jit);
blockLabels[block] = jit.label();
ASSERT(block->size() >= 1);
for (unsigned i = 0; i < block->size() - 1; ++i) {
CCallHelpers::Jump jump = block->at(i).generate(jit, context);
ASSERT_UNUSED(jump, !jump.isSet());
}
if (block->last().opcode == Jump
&& block->successorBlock(0) == code.findNextBlock(block))
continue;
if (block->last().opcode == Ret) {
// We currently don't represent the full prologue/epilogue in Air, so we need to
// have this override.
if (code.frameSize())
jit.emitFunctionEpilogue();
else
jit.emitFunctionEpilogueWithEmptyFrame();
jit.ret();
continue;
}
CCallHelpers::Jump jump = block->last().generate(jit, context);
switch (block->numSuccessors()) {
case 0:
ASSERT(!jump.isSet());
break;
case 1:
link(jump, block->successorBlock(0));
break;
case 2:
link(jump, block->successorBlock(0));
if (block->successorBlock(1) != code.findNextBlock(block))
link(jit.jump(), block->successorBlock(1));
break;
default:
RELEASE_ASSERT_NOT_REACHED();
break;
}
}
for (auto& latePath : context.latePaths)
latePath->run(jit, context);
}
