/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- * vim: set ts=8 sts=2 et sw=2 tw=80: * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ #include "jit/arm/SharedICHelpers-arm.h" #include "jit/Bailouts.h" #include "jit/BaselineFrame.h" #include "jit/CalleeToken.h" #include "jit/JitFrames.h" #include "jit/JitRuntime.h" #include "jit/JitSpewer.h" #ifdef JS_ION_PERF # include "jit/PerfSpewer.h" #endif #include "jit/VMFunctions.h" #include "vm/JitActivation.h" // js::jit::JitActivation #include "vm/JSContext.h" #include "vm/Realm.h" #include "jit/MacroAssembler-inl.h" using namespace js; using namespace js::jit; static const FloatRegisterSet NonVolatileFloatRegs = FloatRegisterSet( (1ULL << FloatRegisters::d8) | (1ULL << FloatRegisters::d9) | (1ULL << FloatRegisters::d10) | (1ULL << FloatRegisters::d11) | (1ULL << FloatRegisters::d12) | (1ULL << FloatRegisters::d13) | (1ULL << FloatRegisters::d14) | (1ULL << FloatRegisters::d15)); static void GenerateReturn(MacroAssembler& masm, int returnCode) { // Restore non-volatile floating point registers. masm.transferMultipleByRuns(NonVolatileFloatRegs, IsLoad, StackPointer, IA); // Get rid of padding word. masm.addPtr(Imm32(sizeof(void*)), sp); // Set up return value masm.ma_mov(Imm32(returnCode), r0); // Pop and return masm.startDataTransferM(IsLoad, sp, IA, WriteBack); masm.transferReg(r4); masm.transferReg(r5); masm.transferReg(r6); masm.transferReg(r7); masm.transferReg(r8); masm.transferReg(r9); masm.transferReg(r10); masm.transferReg(r11); // r12 isn't saved, so it shouldn't be restored. masm.transferReg(pc); masm.finishDataTransfer(); masm.flushBuffer(); } struct EnterJITStack { double d8; double d9; double d10; double d11; double d12; double d13; double d14; double d15; // Padding. void* padding; // Non-volatile registers. void* r4; void* r5; void* r6; void* r7; void* r8; void* r9; void* r10; void* r11; // The abi does not expect r12 (ip) to be preserved void* lr; // Arguments. // code == r0 // argc == r1 // argv == r2 // frame == r3 CalleeToken token; JSObject* scopeChain; size_t numStackValues; Value* vp; }; /* * This method generates a trampoline for a c++ function with the following * signature: * void enter(void* code, int argc, Value* argv, InterpreterFrame* fp, * CalleeToken calleeToken, JSObject* scopeChain, Value* vp) * ...using standard EABI calling convention */ void JitRuntime::generateEnterJIT(JSContext* cx, MacroAssembler& masm) { enterJITOffset_ = startTrampolineCode(masm); const Address slot_token(sp, offsetof(EnterJITStack, token)); const Address slot_vp(sp, offsetof(EnterJITStack, vp)); static_assert(OsrFrameReg == r3); Assembler* aasm = &masm; // Save non-volatile registers. These must be saved by the trampoline, // rather than the JIT'd code, because they are scanned by the conservative // scanner. masm.startDataTransferM(IsStore, sp, DB, WriteBack); masm.transferReg(r4); // [sp,0] masm.transferReg(r5); // [sp,4] masm.transferReg(r6); // [sp,8] masm.transferReg(r7); // [sp,12] masm.transferReg(r8); // [sp,16] masm.transferReg(r9); // [sp,20] masm.transferReg(r10); // [sp,24] masm.transferReg(r11); // [sp,28] // The abi does not expect r12 (ip) to be preserved masm.transferReg(lr); // [sp,32] // The 5th argument is located at [sp, 36] masm.finishDataTransfer(); // Add padding word. masm.subPtr(Imm32(sizeof(void*)), sp); // Push the float registers. masm.transferMultipleByRuns(NonVolatileFloatRegs, IsStore, sp, DB); // Save stack pointer into r8 masm.movePtr(sp, r8); // Load calleeToken into r9. masm.loadPtr(slot_token, r9); // Save stack pointer. masm.movePtr(sp, r11); // Load the number of actual arguments into r10. masm.loadPtr(slot_vp, r10); masm.unboxInt32(Address(r10, 0), r10); { Label noNewTarget; masm.branchTest32(Assembler::Zero, r9, Imm32(CalleeToken_FunctionConstructing), &noNewTarget); masm.add32(Imm32(1), r1); masm.bind(&noNewTarget); } // Guarantee stack alignment of Jit frames. // // This code moves the stack pointer to the location where it should be when // we enter the Jit frame. It moves the stack pointer such that we have // enough space reserved for pushing the arguments, and the JitFrameLayout. // The stack pointer is also aligned on the alignment expected by the Jit // frames. // // At the end the register r4, is a pointer to the stack where the first // argument is expected by the Jit frame. // aasm->as_sub(r4, sp, O2RegImmShift(r1, LSL, 3)); // r4 = sp - argc*8 aasm->as_bic(r4, r4, Imm8(JitStackAlignment - 1)); // r4 is now the aligned on the bottom of the list of arguments. static_assert( sizeof(JitFrameLayout) % JitStackAlignment == 0, "No need to consider the JitFrameLayout for aligning the stack"); // sp' = ~(JitStackAlignment - 1) & (sp - argc * sizeof(Value)) // - sizeof(JitFrameLayout) aasm->as_sub(sp, r4, Imm8(sizeof(JitFrameLayout))); // Get a copy of the number of args to use as a decrement counter, also set // the zero condition code. aasm->as_mov(r5, O2Reg(r1), SetCC); // Loop over arguments, copying them from an unknown buffer onto the Ion // stack so they can be accessed from JIT'ed code. { Label header, footer; // If there aren't any arguments, don't do anything. aasm->as_b(&footer, Assembler::Zero); // Get the top of the loop. masm.bind(&header); aasm->as_sub(r5, r5, Imm8(1), SetCC); // We could be more awesome, and unroll this, using a loadm // (particularly since the offset is effectively 0) but that seems more // error prone, and complex. // BIG FAT WARNING: this loads both r6 and r7. aasm->as_extdtr(IsLoad, 64, true, PostIndex, r6, EDtrAddr(r2, EDtrOffImm(8))); aasm->as_extdtr(IsStore, 64, true, PostIndex, r6, EDtrAddr(r4, EDtrOffImm(8))); aasm->as_b(&header, Assembler::NonZero); masm.bind(&footer); } masm.ma_sub(r8, sp, r8); masm.makeFrameDescriptor(r8, FrameType::CppToJSJit, JitFrameLayout::Size()); masm.startDataTransferM(IsStore, sp, IB, NoWriteBack); // [sp] = return address (written later) masm.transferReg(r8); // [sp',4] = descriptor, argc*8+20 masm.transferReg(r9); // [sp',8] = callee token masm.transferReg(r10); // [sp',12] = actual arguments masm.finishDataTransfer(); Label returnLabel; { // Handle Interpreter -> Baseline OSR. AllocatableGeneralRegisterSet regs(GeneralRegisterSet::All()); regs.take(JSReturnOperand); regs.takeUnchecked(OsrFrameReg); regs.take(r11); regs.take(ReturnReg); const Address slot_numStackValues(r11, offsetof(EnterJITStack, numStackValues)); Label notOsr; masm.branchTestPtr(Assembler::Zero, OsrFrameReg, OsrFrameReg, ¬Osr); Register scratch = regs.takeAny(); Register numStackValues = regs.takeAny(); masm.load32(slot_numStackValues, numStackValues); // Write return address. On ARM, CodeLabel is only used for tableswitch, // so we can't use it here to get the return address. Instead, we use pc // + a fixed offset to a jump to returnLabel. The pc register holds pc + // 8, so we add the size of 2 instructions to skip the instructions // emitted by storePtr and jump(&skipJump). { AutoForbidPoolsAndNops afp(&masm, 5); Label skipJump; masm.mov(pc, scratch); masm.addPtr(Imm32(2 * sizeof(uint32_t)), scratch); masm.storePtr(scratch, Address(sp, 0)); masm.jump(&skipJump); masm.jump(&returnLabel); masm.bind(&skipJump); } // Push previous frame pointer. masm.push(r11); // Reserve frame. Register framePtr = r11; masm.subPtr(Imm32(BaselineFrame::Size()), sp); masm.touchFrameValues(numStackValues, scratch, framePtr); masm.mov(sp, framePtr); // Reserve space for locals and stack values. masm.ma_lsl(Imm32(3), numStackValues, scratch); masm.ma_sub(sp, scratch, sp); // Enter exit frame. masm.addPtr( Imm32(BaselineFrame::Size() + BaselineFrame::FramePointerOffset), scratch); masm.makeFrameDescriptor(scratch, FrameType::BaselineJS, ExitFrameLayout::Size()); masm.push(scratch); masm.push(Imm32(0)); // Fake return address. // No GC things to mark on the stack, push a bare token. masm.loadJSContext(scratch); masm.enterFakeExitFrame(scratch, scratch, ExitFrameType::Bare); masm.push(framePtr); // BaselineFrame masm.push(r0); // jitcode using Fn = bool (*)(BaselineFrame * frame, InterpreterFrame * interpFrame, uint32_t numStackValues); masm.setupUnalignedABICall(scratch); masm.passABIArg(r11); // BaselineFrame masm.passABIArg(OsrFrameReg); // InterpreterFrame masm.passABIArg(numStackValues); masm.callWithABI( MoveOp::GENERAL, CheckUnsafeCallWithABI::DontCheckHasExitFrame); Register jitcode = regs.takeAny(); masm.pop(jitcode); masm.pop(framePtr); MOZ_ASSERT(jitcode != ReturnReg); Label error; masm.addPtr(Imm32(ExitFrameLayout::SizeWithFooter()), sp); masm.addPtr(Imm32(BaselineFrame::Size()), framePtr); masm.branchIfFalseBool(ReturnReg, &error); // If OSR-ing, then emit instrumentation for setting lastProfilerFrame // if profiler instrumentation is enabled. { Label skipProfilingInstrumentation; Register realFramePtr = numStackValues; AbsoluteAddress addressOfEnabled( cx->runtime()->geckoProfiler().addressOfEnabled()); masm.branch32(Assembler::Equal, addressOfEnabled, Imm32(0), &skipProfilingInstrumentation); masm.as_add(realFramePtr, framePtr, Imm8(sizeof(void*))); masm.profilerEnterFrame(realFramePtr, scratch); masm.bind(&skipProfilingInstrumentation); } masm.jump(jitcode); // OOM: Load error value, discard return address and previous frame // pointer and return. masm.bind(&error); masm.mov(framePtr, sp); masm.addPtr(Imm32(2 * sizeof(uintptr_t)), sp); masm.moveValue(MagicValue(JS_ION_ERROR), JSReturnOperand); masm.jump(&returnLabel); masm.bind(¬Osr); // Load the scope chain in R1. MOZ_ASSERT(R1.scratchReg() != r0); masm.loadPtr(Address(r11, offsetof(EnterJITStack, scopeChain)), R1.scratchReg()); } // The Data transfer is pushing 4 words, which already account for the // return address space of the Jit frame. We have to undo what the data // transfer did before making the call. masm.addPtr(Imm32(sizeof(uintptr_t)), sp); // The callee will push the return address on the stack, thus we check that // the stack would be aligned once the call is complete. masm.assertStackAlignment(JitStackAlignment, sizeof(uintptr_t)); // Call the function. masm.callJitNoProfiler(r0); // Interpreter -> Baseline OSR will return here. masm.bind(&returnLabel); // The top of the stack now points to the address of the field following the // return address because the return address is popped for the return, so we // need to remove the size of the return address field. aasm->as_sub(sp, sp, Imm8(4)); // Load off of the stack the size of our local stack. masm.loadPtr(Address(sp, JitFrameLayout::offsetOfDescriptor()), r5); aasm->as_add(sp, sp, lsr(r5, FRAMESIZE_SHIFT)); // Store the returned value into the slot_vp masm.loadPtr(slot_vp, r5); masm.storeValue(JSReturnOperand, Address(r5, 0)); // :TODO: Optimize storeValue with: // We're using a load-double here. In order for that to work, the data needs // to be stored in two consecutive registers, make sure this is the case // MOZ_ASSERT(JSReturnReg_Type.code() == JSReturnReg_Data.code()+1); // aasm->as_extdtr(IsStore, 64, true, Offset, // JSReturnReg_Data, EDtrAddr(r5, EDtrOffImm(0))); // Restore non-volatile registers and return. GenerateReturn(masm, true); } void JitRuntime::generateInvalidator(MacroAssembler& masm, Label* bailoutTail) { // See large comment in x86's JitRuntime::generateInvalidator. invalidatorOffset_ = startTrampolineCode(masm); // At this point, one of two things has happened: // 1) Execution has just returned from C code, which left the stack aligned // 2) Execution has just returned from Ion code, which left the stack // unaligned. The old return address should not matter, but we still want the // stack to be aligned, and there is no good reason to automatically align it // with a call to setupUnalignedABICall. masm.as_bic(sp, sp, Imm8(7)); masm.startDataTransferM(IsStore, sp, DB, WriteBack); // We don't have to push everything, but this is likely easier. // Setting regs_. for (uint32_t i = 0; i < Registers::Total; i++) { masm.transferReg(Register::FromCode(i)); } masm.finishDataTransfer(); // Since our datastructures for stack inspection are compile-time fixed, // if there are only 16 double registers, then we need to reserve // space on the stack for the missing 16. if (FloatRegisters::ActualTotalPhys() != FloatRegisters::TotalPhys) { ScratchRegisterScope scratch(masm); int missingRegs = FloatRegisters::TotalPhys - FloatRegisters::ActualTotalPhys(); masm.ma_sub(Imm32(missingRegs * sizeof(double)), sp, scratch); } masm.startFloatTransferM(IsStore, sp, DB, WriteBack); for (uint32_t i = 0; i < FloatRegisters::ActualTotalPhys(); i++) { masm.transferFloatReg(FloatRegister(i, FloatRegister::Double)); } masm.finishFloatTransfer(); masm.ma_mov(sp, r0); const int sizeOfRetval = sizeof(size_t) * 2; masm.reserveStack(sizeOfRetval); masm.mov(sp, r1); const int sizeOfBailoutInfo = sizeof(void*) * 2; masm.reserveStack(sizeOfBailoutInfo); masm.mov(sp, r2); using Fn = bool (*)(InvalidationBailoutStack * sp, size_t * frameSizeOut, BaselineBailoutInfo * *info); masm.setupAlignedABICall(); masm.passABIArg(r0); masm.passABIArg(r1); masm.passABIArg(r2); masm.callWithABI( MoveOp::GENERAL, CheckUnsafeCallWithABI::DontCheckOther); masm.ma_ldr(DTRAddr(sp, DtrOffImm(0)), r2); { ScratchRegisterScope scratch(masm); masm.ma_ldr(Address(sp, sizeOfBailoutInfo), r1, scratch); } // Remove the return address, the IonScript, the register state // (InvaliationBailoutStack) and the space that was allocated for the return // value. { ScratchRegisterScope scratch(masm); masm.ma_add(sp, Imm32(sizeof(InvalidationBailoutStack) + sizeOfRetval + sizeOfBailoutInfo), sp, scratch); } // Remove the space that this frame was using before the bailout (computed // by InvalidationBailout) masm.ma_add(sp, r1, sp); // Jump to shared bailout tail. The BailoutInfo pointer has to be in r2. masm.jump(bailoutTail); } void JitRuntime::generateArgumentsRectifier(MacroAssembler& masm, ArgumentsRectifierKind kind) { switch (kind) { case ArgumentsRectifierKind::Normal: argumentsRectifierOffset_ = startTrampolineCode(masm); break; case ArgumentsRectifierKind::TrialInlining: trialInliningArgumentsRectifierOffset_ = startTrampolineCode(masm); break; } masm.pushReturnAddress(); // Copy number of actual arguments into r0 and r8. masm.ma_ldr( DTRAddr(sp, DtrOffImm(RectifierFrameLayout::offsetOfNumActualArgs())), r0); masm.mov(r0, r8); // Load the number of |undefined|s to push into r6. masm.ma_ldr( DTRAddr(sp, DtrOffImm(RectifierFrameLayout::offsetOfCalleeToken())), r1); { ScratchRegisterScope scratch(masm); masm.ma_and(Imm32(CalleeTokenMask), r1, r6, scratch); } masm.ma_ldrh(EDtrAddr(r6, EDtrOffImm(JSFunction::offsetOfNargs())), r6); masm.ma_sub(r6, r8, r2); // Get the topmost argument. { ScratchRegisterScope scratch(masm); masm.ma_alu(sp, lsl(r8, 3), r3, OpAdd); // r3 <- r3 + nargs * 8 masm.ma_add(r3, Imm32(sizeof(RectifierFrameLayout)), r3, scratch); } { Label notConstructing; masm.branchTest32(Assembler::Zero, r1, Imm32(CalleeToken_FunctionConstructing), ¬Constructing); // Add sizeof(Value) to overcome |this| masm.as_extdtr(IsLoad, 64, true, Offset, r4, EDtrAddr(r3, EDtrOffImm(8))); masm.as_extdtr(IsStore, 64, true, PreIndex, r4, EDtrAddr(sp, EDtrOffImm(-8))); // Include the newly pushed newTarget value in the frame size // calculated below. masm.add32(Imm32(1), r6); masm.bind(¬Constructing); } // Push undefined. masm.moveValue(UndefinedValue(), ValueOperand(r5, r4)); { Label undefLoopTop; masm.bind(&undefLoopTop); masm.as_extdtr(IsStore, 64, true, PreIndex, r4, EDtrAddr(sp, EDtrOffImm(-8))); masm.as_sub(r2, r2, Imm8(1), SetCC); masm.ma_b(&undefLoopTop, Assembler::NonZero); } // Push arguments, |nargs| + 1 times (to include |this|). { Label copyLoopTop; masm.bind(©LoopTop); masm.as_extdtr(IsLoad, 64, true, PostIndex, r4, EDtrAddr(r3, EDtrOffImm(-8))); masm.as_extdtr(IsStore, 64, true, PreIndex, r4, EDtrAddr(sp, EDtrOffImm(-8))); masm.as_sub(r8, r8, Imm8(1), SetCC); masm.ma_b(©LoopTop, Assembler::NotSigned); } // translate the framesize from values into bytes masm.as_add(r6, r6, Imm8(1)); masm.ma_lsl(Imm32(3), r6, r6); // Construct sizeDescriptor. masm.makeFrameDescriptor(r6, FrameType::Rectifier, JitFrameLayout::Size()); // Construct JitFrameLayout. masm.ma_push(r0); // actual arguments. masm.ma_push(r1); // callee token masm.ma_push(r6); // frame descriptor. // Call the target function. masm.andPtr(Imm32(CalleeTokenMask), r1); switch (kind) { case ArgumentsRectifierKind::Normal: masm.loadJitCodeRaw(r1, r3); argumentsRectifierReturnOffset_ = masm.callJitNoProfiler(r3); break; case ArgumentsRectifierKind::TrialInlining: Label noBaselineScript, done; masm.loadBaselineJitCodeRaw(r1, r3, &noBaselineScript); masm.callJitNoProfiler(r3); masm.jump(&done); // See BaselineCacheIRCompiler::emitCallInlinedFunction. masm.bind(&noBaselineScript); masm.loadJitCodeRaw(r1, r3); masm.callJitNoProfiler(r3); masm.bind(&done); break; } // arg1 // ... // argN // num actual args // callee token // sizeDescriptor <- sp now // return address // Remove the rectifier frame. { ScratchRegisterScope scratch(masm); masm.ma_dtr(IsLoad, sp, Imm32(12), r4, scratch, PostIndex); } // arg1 // ... // argN <- sp now; r4 <- frame descriptor // num actual args // callee token // sizeDescriptor // return address // Discard pushed arguments. masm.ma_alu(sp, lsr(r4, FRAMESIZE_SHIFT), sp, OpAdd); masm.ret(); } static void PushBailoutFrame(MacroAssembler& masm, uint32_t frameClass, Register spArg) { #ifdef ENABLE_WASM_SIMD # error "Needs more careful logic if SIMD is enabled" #endif // the stack should look like: // [IonFrame] // bailoutFrame.registersnapshot // bailoutFrame.fpsnapshot // bailoutFrame.snapshotOffset // bailoutFrame.frameSize // STEP 1a: Save our register sets to the stack so Bailout() can read // everything. // sp % 8 == 0 masm.startDataTransferM(IsStore, sp, DB, WriteBack); // We don't have to push everything, but this is likely easier. // Setting regs_. for (uint32_t i = 0; i < Registers::Total; i++) { masm.transferReg(Register::FromCode(i)); } masm.finishDataTransfer(); ScratchRegisterScope scratch(masm); // Since our datastructures for stack inspection are compile-time fixed, // if there are only 16 double registers, then we need to reserve // space on the stack for the missing 16. if (FloatRegisters::ActualTotalPhys() != FloatRegisters::TotalPhys) { int missingRegs = FloatRegisters::TotalPhys - FloatRegisters::ActualTotalPhys(); masm.ma_sub(Imm32(missingRegs * sizeof(double)), sp, scratch); } masm.startFloatTransferM(IsStore, sp, DB, WriteBack); for (uint32_t i = 0; i < FloatRegisters::ActualTotalPhys(); i++) { masm.transferFloatReg(FloatRegister(i, FloatRegister::Double)); } masm.finishFloatTransfer(); // STEP 1b: Push both the "return address" of the function call (the address // of the instruction after the call that we used to get here) as // well as the callee token onto the stack. The return address is // currently in r14. We will proceed by loading the callee token // into a sacrificial register <= r14, then pushing both onto the // stack. // Now place the frameClass onto the stack, via a register. masm.ma_mov(Imm32(frameClass), r4); // And onto the stack. Since the stack is full, we need to put this one past // the end of the current stack. Sadly, the ABI says that we need to always // point to the lowest place that has been written. The OS is free to do // whatever it wants below sp. masm.startDataTransferM(IsStore, sp, DB, WriteBack); // Set frameClassId_. masm.transferReg(r4); // Set tableOffset_; higher registers are stored at higher locations on the // stack. masm.transferReg(lr); masm.finishDataTransfer(); masm.ma_mov(sp, spArg); } static void GenerateBailoutThunk(MacroAssembler& masm, uint32_t frameClass, Label* bailoutTail) { PushBailoutFrame(masm, frameClass, r0); // SP % 8 == 4 // STEP 1c: Call the bailout function, giving a pointer to the // structure we just blitted onto the stack. const int sizeOfBailoutInfo = sizeof(void*) * 2; masm.reserveStack(sizeOfBailoutInfo); masm.mov(sp, r1); using Fn = bool (*)(BailoutStack * sp, BaselineBailoutInfo * *info); masm.setupAlignedABICall(); // Decrement sp by another 4, so we keep alignment. Not Anymore! Pushing // both the snapshotoffset as well as the: masm.as_sub(sp, sp, Imm8(4)); // Set the old (4-byte aligned) value of the sp as the first argument. masm.passABIArg(r0); masm.passABIArg(r1); // Sp % 8 == 0 masm.callWithABI(MoveOp::GENERAL, CheckUnsafeCallWithABI::DontCheckOther); masm.ma_ldr(DTRAddr(sp, DtrOffImm(0)), r2); { ScratchRegisterScope scratch(masm); masm.ma_add(sp, Imm32(sizeOfBailoutInfo), sp, scratch); } // Common size of a bailout frame. uint32_t bailoutFrameSize = 0 + sizeof(void*) // frameClass + sizeof(RegisterDump); if (frameClass == NO_FRAME_SIZE_CLASS_ID) { // Make sure the bailout frame size fits into the offset for a load. masm.as_dtr(IsLoad, 32, Offset, r4, DTRAddr(sp, DtrOffImm(4))); // Used to be: offsetof(BailoutStack, frameSize_) // This structure is no longer available to us :( // We add 12 to the bailoutFrameSize because: // sizeof(uint32_t) for the tableOffset that was pushed onto the stack // sizeof(uintptr_t) for the snapshotOffset; // alignment to round the uintptr_t up to a multiple of 8 bytes. ScratchRegisterScope scratch(masm); masm.ma_add(sp, Imm32(bailoutFrameSize + 12), sp, scratch); masm.as_add(sp, sp, O2Reg(r4)); } else { ScratchRegisterScope scratch(masm); uint32_t frameSize = FrameSizeClass::FromClass(frameClass).frameSize(); masm.ma_add(Imm32( // The frame that was added when we entered the most // recent function. frameSize // The size of the "return address" that was dumped on // the stack. + sizeof(void*) // Everything else that was pushed on the stack. + bailoutFrameSize), sp, scratch); } // Jump to shared bailout tail. The BailoutInfo pointer has to be in r2. masm.jump(bailoutTail); } JitRuntime::BailoutTable JitRuntime::generateBailoutTable(MacroAssembler& masm, Label* bailoutTail, uint32_t frameClass) { uint32_t offset = startTrampolineCode(masm); { // Emit the table without any pools being inserted. Label bailout; AutoForbidPoolsAndNops afp(&masm, BAILOUT_TABLE_SIZE); for (size_t i = 0; i < BAILOUT_TABLE_SIZE; i++) { masm.ma_bl(&bailout); } masm.bind(&bailout); } GenerateBailoutThunk(masm, frameClass, bailoutTail); return BailoutTable(offset, masm.currentOffset() - offset); } void JitRuntime::generateBailoutHandler(MacroAssembler& masm, Label* bailoutTail) { bailoutHandlerOffset_ = startTrampolineCode(masm); GenerateBailoutThunk(masm, NO_FRAME_SIZE_CLASS_ID, bailoutTail); } bool JitRuntime::generateVMWrapper(JSContext* cx, MacroAssembler& masm, const VMFunctionData& f, DynFn nativeFun, uint32_t* wrapperOffset) { *wrapperOffset = startTrampolineCode(masm); AllocatableGeneralRegisterSet regs(Register::Codes::WrapperMask); static_assert( (Register::Codes::VolatileMask & ~Register::Codes::WrapperMask) == 0, "Wrapper register set must be a superset of Volatile register set."); // The context is the first argument; r0 is the first argument register. Register cxreg = r0; regs.take(cxreg); // Stack is: // ... frame ... // +8 [args] + argPadding // +0 ExitFrame // // We're aligned to an exit frame, so link it up. // If it isn't a tail call, then the return address needs to be saved if (f.expectTailCall == NonTailCall) { masm.pushReturnAddress(); } masm.loadJSContext(cxreg); masm.enterExitFrame(cxreg, regs.getAny(), &f); // Save the base of the argument set stored on the stack. Register argsBase = InvalidReg; if (f.explicitArgs) { argsBase = r5; regs.take(argsBase); ScratchRegisterScope scratch(masm); masm.ma_add(sp, Imm32(ExitFrameLayout::SizeWithFooter()), argsBase, scratch); } // Reserve space for the outparameter. Register outReg = InvalidReg; switch (f.outParam) { case Type_Value: outReg = r4; regs.take(outReg); masm.reserveStack(sizeof(Value)); masm.ma_mov(sp, outReg); break; case Type_Handle: outReg = r4; regs.take(outReg); masm.PushEmptyRooted(f.outParamRootType); masm.ma_mov(sp, outReg); break; case Type_Int32: case Type_Pointer: case Type_Bool: outReg = r4; regs.take(outReg); masm.reserveStack(sizeof(int32_t)); masm.ma_mov(sp, outReg); break; case Type_Double: outReg = r4; regs.take(outReg); masm.reserveStack(sizeof(double)); masm.ma_mov(sp, outReg); break; default: MOZ_ASSERT(f.outParam == Type_Void); break; } if (!generateTLEnterVM(masm, f)) { return false; } masm.setupUnalignedABICall(regs.getAny()); masm.passABIArg(cxreg); size_t argDisp = 0; // Copy any arguments. for (uint32_t explicitArg = 0; explicitArg < f.explicitArgs; explicitArg++) { switch (f.argProperties(explicitArg)) { case VMFunctionData::WordByValue: masm.passABIArg(MoveOperand(argsBase, argDisp), MoveOp::GENERAL); argDisp += sizeof(void*); break; case VMFunctionData::DoubleByValue: // Values should be passed by reference, not by value, so we assert // that the argument is a double-precision float. MOZ_ASSERT(f.argPassedInFloatReg(explicitArg)); masm.passABIArg(MoveOperand(argsBase, argDisp), MoveOp::DOUBLE); argDisp += sizeof(double); break; case VMFunctionData::WordByRef: masm.passABIArg( MoveOperand(argsBase, argDisp, MoveOperand::EFFECTIVE_ADDRESS), MoveOp::GENERAL); argDisp += sizeof(void*); break; case VMFunctionData::DoubleByRef: masm.passABIArg( MoveOperand(argsBase, argDisp, MoveOperand::EFFECTIVE_ADDRESS), MoveOp::GENERAL); argDisp += 2 * sizeof(void*); break; } } // Copy the implicit outparam, if any. if (outReg != InvalidReg) { masm.passABIArg(outReg); } masm.callWithABI(nativeFun, MoveOp::GENERAL, CheckUnsafeCallWithABI::DontCheckHasExitFrame); if (!generateTLExitVM(masm, f)) { return false; } // Test for failure. switch (f.failType()) { case Type_Object: masm.branchTestPtr(Assembler::Zero, r0, r0, masm.failureLabel()); break; case Type_Bool: masm.branchIfFalseBool(r0, masm.failureLabel()); break; case Type_Void: break; default: MOZ_CRASH("unknown failure kind"); } // Load the outparam and free any allocated stack. switch (f.outParam) { case Type_Handle: masm.popRooted(f.outParamRootType, ReturnReg, JSReturnOperand); break; case Type_Value: masm.loadValue(Address(sp, 0), JSReturnOperand); masm.freeStack(sizeof(Value)); break; case Type_Int32: case Type_Pointer: masm.load32(Address(sp, 0), ReturnReg); masm.freeStack(sizeof(int32_t)); break; case Type_Bool: masm.load8ZeroExtend(Address(sp, 0), ReturnReg); masm.freeStack(sizeof(int32_t)); break; case Type_Double: if (JitOptions.supportsFloatingPoint) { masm.loadDouble(Address(sp, 0), ReturnDoubleReg); } else { masm.assumeUnreachable( "Unable to load into float reg, with no FP support."); } masm.freeStack(sizeof(double)); break; default: MOZ_ASSERT(f.outParam == Type_Void); break; } // Until C++ code is instrumented against Spectre, prevent speculative // execution from returning any private data. if (f.returnsData() && JitOptions.spectreJitToCxxCalls) { masm.speculationBarrier(); } masm.leaveExitFrame(); masm.retn(Imm32(sizeof(ExitFrameLayout) + f.explicitStackSlots() * sizeof(void*) + f.extraValuesToPop * sizeof(Value))); return true; } uint32_t JitRuntime::generatePreBarrier(JSContext* cx, MacroAssembler& masm, MIRType type) { uint32_t offset = startTrampolineCode(masm); masm.pushReturnAddress(); static_assert(PreBarrierReg == r1); Register temp1 = r2; Register temp2 = r3; Register temp3 = r4; masm.push(temp1); masm.push(temp2); masm.push(temp3); Label noBarrier; masm.emitPreBarrierFastPath(cx->runtime(), type, temp1, temp2, temp3, &noBarrier); // Call into C++ to mark this GC thing. masm.pop(temp3); masm.pop(temp2); masm.pop(temp1); LiveRegisterSet save; if (JitOptions.supportsFloatingPoint) { save.set() = RegisterSet(GeneralRegisterSet(Registers::VolatileMask), FloatRegisterSet(FloatRegisters::VolatileDoubleMask)); } else { save.set() = RegisterSet(GeneralRegisterSet(Registers::VolatileMask), FloatRegisterSet()); } masm.PushRegsInMask(save); masm.movePtr(ImmPtr(cx->runtime()), r0); masm.setupUnalignedABICall(r2); masm.passABIArg(r0); masm.passABIArg(r1); masm.callWithABI(JitMarkFunction(type)); masm.PopRegsInMask(save); masm.ret(); masm.bind(&noBarrier); masm.pop(temp3); masm.pop(temp2); masm.pop(temp1); masm.ret(); return offset; } void JitRuntime::generateExceptionTailStub(MacroAssembler& masm, Label* profilerExitTail) { exceptionTailOffset_ = startTrampolineCode(masm); masm.bind(masm.failureLabel()); masm.handleFailureWithHandlerTail(profilerExitTail); } void JitRuntime::generateBailoutTailStub(MacroAssembler& masm, Label* bailoutTail) { bailoutTailOffset_ = startTrampolineCode(masm); masm.bind(bailoutTail); masm.generateBailoutTail(r1, r2); } void JitRuntime::generateProfilerExitFrameTailStub(MacroAssembler& masm, Label* profilerExitTail) { profilerExitFrameTailOffset_ = startTrampolineCode(masm); masm.bind(profilerExitTail); Register scratch1 = r5; Register scratch2 = r6; Register scratch3 = r7; Register scratch4 = r8; // // The code generated below expects that the current stack pointer points // to an Ion or Baseline frame, at the state it would be immediately // before a ret(). Thus, after this stub's business is done, it executes // a ret() and returns directly to the caller script, on behalf of the // callee script that jumped to this code. // // Thus the expected stack is: // // StackPointer ----+ // v // ..., ActualArgc, CalleeToken, Descriptor, ReturnAddr // MEM-HI MEM-LOW // // // The generated jitcode is responsible for overwriting the // jitActivation->lastProfilingFrame field with a pointer to the previous // Ion or Baseline jit-frame that was pushed before this one. It is also // responsible for overwriting jitActivation->lastProfilingCallSite with // the return address into that frame. The frame could either be an // immediate "caller" frame, or it could be a frame in a previous // JitActivation (if the current frame was entered from C++, and the C++ // was entered by some caller jit-frame further down the stack). // // So this jitcode is responsible for "walking up" the jit stack, finding // the previous Ion or Baseline JS frame, and storing its address and the // return address into the appropriate fields on the current jitActivation. // // There are a fixed number of different path types that can lead to the // current frame, which is either a baseline or ion frame: // // // ^ // | // ^--- Ion // | // ^--- Baseline Stub <---- Baseline // | // ^--- Argument Rectifier // | ^ // | | // | ^--- Ion // | | // | ^--- Baseline Stub <---- Baseline // | // ^--- Entry Frame (From C++) // Register actReg = scratch4; masm.loadJSContext(actReg); masm.loadPtr(Address(actReg, offsetof(JSContext, profilingActivation_)), actReg); Address lastProfilingFrame(actReg, JitActivation::offsetOfLastProfilingFrame()); Address lastProfilingCallSite(actReg, JitActivation::offsetOfLastProfilingCallSite()); #ifdef DEBUG // Ensure that frame we are exiting is current lastProfilingFrame { masm.loadPtr(lastProfilingFrame, scratch1); Label checkOk; masm.branchPtr(Assembler::Equal, scratch1, ImmWord(0), &checkOk); masm.branchPtr(Assembler::Equal, StackPointer, scratch1, &checkOk); masm.assumeUnreachable( "Mismatch between stored lastProfilingFrame and current stack " "pointer."); masm.bind(&checkOk); } #endif // Load the frame descriptor into |scratch1|, figure out what to do depending // on its type. masm.loadPtr(Address(StackPointer, JitFrameLayout::offsetOfDescriptor()), scratch1); // Going into the conditionals, we will have: // FrameDescriptor.size in scratch1 // FrameDescriptor.type in scratch2 { ScratchRegisterScope asmScratch(masm); masm.ma_and(Imm32((1 << FRAMETYPE_BITS) - 1), scratch1, scratch2, asmScratch); } masm.rshiftPtr(Imm32(FRAMESIZE_SHIFT), scratch1); // Handling of each case is dependent on FrameDescriptor.type Label handle_IonJS; Label handle_BaselineStub; Label handle_Rectifier; Label handle_IonICCall; Label handle_Entry; Label end; masm.branch32(Assembler::Equal, scratch2, Imm32(FrameType::IonJS), &handle_IonJS); masm.branch32(Assembler::Equal, scratch2, Imm32(FrameType::BaselineJS), &handle_IonJS); masm.branch32(Assembler::Equal, scratch2, Imm32(FrameType::BaselineStub), &handle_BaselineStub); masm.branch32(Assembler::Equal, scratch2, Imm32(FrameType::Rectifier), &handle_Rectifier); masm.branch32(Assembler::Equal, scratch2, Imm32(FrameType::IonICCall), &handle_IonICCall); masm.branch32(Assembler::Equal, scratch2, Imm32(FrameType::CppToJSJit), &handle_Entry); // The WasmToJSJit is just another kind of entry. masm.branch32(Assembler::Equal, scratch2, Imm32(FrameType::WasmToJSJit), &handle_Entry); masm.assumeUnreachable( "Invalid caller frame type when exiting from Ion frame."); // // FrameType::IonJS // // Stack layout: // ... // Ion-Descriptor // Prev-FP ---> Ion-ReturnAddr // ... previous frame data ... |- Descriptor.Size // ... arguments ... | // ActualArgc | // CalleeToken |- JitFrameLayout::Size() // Descriptor | // FP -----> ReturnAddr | // masm.bind(&handle_IonJS); { // |scratch1| contains Descriptor.size // returning directly to an IonJS frame. Store return addr to frame // in lastProfilingCallSite. masm.loadPtr(Address(StackPointer, JitFrameLayout::offsetOfReturnAddress()), scratch2); masm.storePtr(scratch2, lastProfilingCallSite); // Store return frame in lastProfilingFrame. // scratch2 := StackPointer + Descriptor.size*1 + JitFrameLayout::Size(); masm.ma_add(StackPointer, scratch1, scratch2); masm.as_add(scratch2, scratch2, Imm8(JitFrameLayout::Size())); masm.storePtr(scratch2, lastProfilingFrame); masm.ret(); } // // FrameType::BaselineStub // // Look past the stub and store the frame pointer to // the baselineJS frame prior to it. // // Stack layout: // ... // BL-Descriptor // Prev-FP ---> BL-ReturnAddr // +-----> BL-PrevFramePointer // | ... BL-FrameData ... // | BLStub-Descriptor // | BLStub-ReturnAddr // | BLStub-StubPointer | // +------ BLStub-SavedFramePointer |- Descriptor.Size // ... arguments ... | // ActualArgc | // CalleeToken |- JitFrameLayout::Size() // Descriptor | // FP -----> ReturnAddr | // // We take advantage of the fact that the stub frame saves the frame // pointer pointing to the baseline frame, so a bunch of calculation can // be avoided. // masm.bind(&handle_BaselineStub); { masm.ma_add(StackPointer, scratch1, scratch3); Address stubFrameReturnAddr( scratch3, JitFrameLayout::Size() + BaselineStubFrameLayout::offsetOfReturnAddress()); masm.loadPtr(stubFrameReturnAddr, scratch2); masm.storePtr(scratch2, lastProfilingCallSite); Address stubFrameSavedFramePtr( scratch3, JitFrameLayout::Size() - (2 * sizeof(void*))); masm.loadPtr(stubFrameSavedFramePtr, scratch2); masm.addPtr(Imm32(sizeof(void*)), scratch2); // Skip past BL-PrevFramePtr masm.storePtr(scratch2, lastProfilingFrame); masm.ret(); } // // FrameType::Rectifier // // The rectifier frame can be preceded by either an IonJS, a BaselineStub, // or a CppToJSJit/WasmToJSJit frame. // // Stack layout if caller of rectifier was Ion or CppToJSJit/WasmToJSJit: // // Ion-Descriptor // Ion-ReturnAddr // ... ion frame data ... |- Rect-Descriptor.Size // < COMMON LAYOUT > // // Stack layout if caller of rectifier was Baseline: // // BL-Descriptor // Prev-FP ---> BL-ReturnAddr // +-----> BL-SavedFramePointer // | ... baseline frame data ... // | BLStub-Descriptor // | BLStub-ReturnAddr // | BLStub-StubPointer | // +------ BLStub-SavedFramePointer |- Rect-Descriptor.Size // ... args to rectifier ... | // < COMMON LAYOUT > // // Common stack layout: // // ActualArgc | // CalleeToken |- IonRectitiferFrameLayout::Size() // Rect-Descriptor | // Rect-ReturnAddr | // ... rectifier data & args ... |- Descriptor.Size // ActualArgc | // CalleeToken |- JitFrameLayout::Size() // Descriptor | // FP -----> ReturnAddr | // masm.bind(&handle_Rectifier); { // scratch2 := StackPointer + Descriptor.size*1 + JitFrameLayout::Size(); masm.ma_add(StackPointer, scratch1, scratch2); masm.add32(Imm32(JitFrameLayout::Size()), scratch2); masm.loadPtr(Address(scratch2, RectifierFrameLayout::offsetOfDescriptor()), scratch3); masm.ma_lsr(Imm32(FRAMESIZE_SHIFT), scratch3, scratch1); masm.and32(Imm32((1 << FRAMETYPE_BITS) - 1), scratch3); // Now |scratch1| contains Rect-Descriptor.Size // and |scratch2| points to Rectifier frame // and |scratch3| contains Rect-Descriptor.Type masm.assertRectifierFrameParentType(scratch3); // Check for either Ion or BaselineStub frame. Label notIonFrame; masm.branch32(Assembler::NotEqual, scratch3, Imm32(FrameType::IonJS), ¬IonFrame); // Handle Rectifier <- IonJS // scratch3 := RectFrame[ReturnAddr] masm.loadPtr( Address(scratch2, RectifierFrameLayout::offsetOfReturnAddress()), scratch3); masm.storePtr(scratch3, lastProfilingCallSite); // scratch3 := RectFrame + Rect-Descriptor.Size + // RectifierFrameLayout::Size() masm.ma_add(scratch2, scratch1, scratch3); masm.add32(Imm32(RectifierFrameLayout::Size()), scratch3); masm.storePtr(scratch3, lastProfilingFrame); masm.ret(); masm.bind(¬IonFrame); // Check for either BaselineStub or a CppToJSJit/WasmToJSJit entry // frame. masm.branch32(Assembler::NotEqual, scratch3, Imm32(FrameType::BaselineStub), &handle_Entry); // Handle Rectifier <- BaselineStub <- BaselineJS masm.ma_add(scratch2, scratch1, scratch3); Address stubFrameReturnAddr( scratch3, RectifierFrameLayout::Size() + BaselineStubFrameLayout::offsetOfReturnAddress()); masm.loadPtr(stubFrameReturnAddr, scratch2); masm.storePtr(scratch2, lastProfilingCallSite); Address stubFrameSavedFramePtr( scratch3, RectifierFrameLayout::Size() - (2 * sizeof(void*))); masm.loadPtr(stubFrameSavedFramePtr, scratch2); masm.addPtr(Imm32(sizeof(void*)), scratch2); masm.storePtr(scratch2, lastProfilingFrame); masm.ret(); } // FrameType::IonICCall // // The caller is always an IonJS frame. // // Ion-Descriptor // Ion-ReturnAddr // ... ion frame data ... |- CallFrame-Descriptor.Size // StubCode | // ICCallFrame-Descriptor |- IonICCallFrameLayout::Size() // ICCallFrame-ReturnAddr | // ... call frame data & args ... |- Descriptor.Size // ActualArgc | // CalleeToken |- JitFrameLayout::Size() // Descriptor | // FP -----> ReturnAddr | masm.bind(&handle_IonICCall); { // scratch2 := StackPointer + Descriptor.size + JitFrameLayout::Size() masm.ma_add(StackPointer, scratch1, scratch2); masm.addPtr(Imm32(JitFrameLayout::Size()), scratch2); // scratch3 := ICCallFrame-Descriptor.Size masm.loadPtr(Address(scratch2, IonICCallFrameLayout::offsetOfDescriptor()), scratch3); #ifdef DEBUG // Assert previous frame is an IonJS frame. masm.movePtr(scratch3, scratch1); masm.and32(Imm32((1 << FRAMETYPE_BITS) - 1), scratch1); { Label checkOk; masm.branch32(Assembler::Equal, scratch1, Imm32(FrameType::IonJS), &checkOk); masm.assumeUnreachable("IonICCall frame must be preceded by IonJS frame"); masm.bind(&checkOk); } #endif masm.rshiftPtr(Imm32(FRAMESIZE_SHIFT), scratch3); // lastProfilingCallSite := ICCallFrame-ReturnAddr masm.loadPtr( Address(scratch2, IonICCallFrameLayout::offsetOfReturnAddress()), scratch1); masm.storePtr(scratch1, lastProfilingCallSite); // lastProfilingFrame := ICCallFrame + ICCallFrame-Descriptor.Size + // IonICCallFrameLayout::Size() masm.ma_add(scratch2, scratch3, scratch1); masm.addPtr(Imm32(IonICCallFrameLayout::Size()), scratch1); masm.storePtr(scratch1, lastProfilingFrame); masm.ret(); } // // FrameType::CppToJSJit / FrameType::WasmToJSJit // // If at an entry frame, store null into both fields. // A fast-path wasm->jit transition frame is an entry frame from the point // of view of the JIT. // masm.bind(&handle_Entry); { masm.movePtr(ImmPtr(nullptr), scratch1); masm.storePtr(scratch1, lastProfilingCallSite); masm.storePtr(scratch1, lastProfilingFrame); masm.ret(); } }