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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
commit5f8de423f190bbb79a62f804151bc24824fa32d8 (patch)
tree10027f336435511475e392454359edea8e25895d /js/src/jit/arm64/Trampoline-arm64.cpp
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
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Add m-esr52 at 52.6.0
Diffstat (limited to 'js/src/jit/arm64/Trampoline-arm64.cpp')
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diff --git a/js/src/jit/arm64/Trampoline-arm64.cpp b/js/src/jit/arm64/Trampoline-arm64.cpp
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ * 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/Bailouts.h"
+#include "jit/JitCompartment.h"
+#include "jit/JitFrames.h"
+#include "jit/Linker.h"
+#ifdef JS_ION_PERF
+# include "jit/PerfSpewer.h"
+#endif
+#include "jit/arm64/SharedICHelpers-arm64.h"
+#include "jit/VMFunctions.h"
+
+#include "jit/MacroAssembler-inl.h"
+
+using namespace js;
+using namespace js::jit;
+
+// All registers to save and restore. This includes the stack pointer, since we
+// use the ability to reference register values on the stack by index.
+static const LiveRegisterSet AllRegs =
+ LiveRegisterSet(GeneralRegisterSet(Registers::AllMask & ~(1 << 31 | 1 << 30 | 1 << 29| 1 << 28)),
+ FloatRegisterSet(FloatRegisters::AllMask));
+
+/* This method generates a trampoline on ARM64 for a c++ function with
+ * the following signature:
+ * bool blah(void* code, int argc, Value* argv, JSObject* scopeChain, Value* vp)
+ * ...using standard AArch64 calling convention
+ */
+JitCode*
+JitRuntime::generateEnterJIT(JSContext* cx, EnterJitType type)
+{
+ MacroAssembler masm(cx);
+
+ const Register reg_code = IntArgReg0; // EnterJitData::jitcode.
+ const Register reg_argc = IntArgReg1; // EnterJitData::maxArgc.
+ const Register reg_argv = IntArgReg2; // EnterJitData::maxArgv.
+ const Register reg_osrFrame = IntArgReg3; // EnterJitData::osrFrame.
+ const Register reg_callee = IntArgReg4; // EnterJitData::calleeToken.
+ const Register reg_scope = IntArgReg5; // EnterJitData::scopeChain.
+ const Register reg_osrNStack = IntArgReg6; // EnterJitData::osrNumStackValues.
+ const Register reg_vp = IntArgReg7; // Address of EnterJitData::result.
+
+ MOZ_ASSERT(OsrFrameReg == IntArgReg3);
+
+ // During the pushes below, use the normal stack pointer.
+ masm.SetStackPointer64(sp);
+
+ // Save old frame pointer and return address; set new frame pointer.
+ masm.push(r29, r30);
+ masm.moveStackPtrTo(r29);
+
+ // Save callee-save integer registers.
+ // Also save x7 (reg_vp) and x30 (lr), for use later.
+ masm.push(r19, r20, r21, r22);
+ masm.push(r23, r24, r25, r26);
+ masm.push(r27, r28, r7, r30);
+
+ // Save callee-save floating-point registers.
+ // AArch64 ABI specifies that only the lower 64 bits must be saved.
+ masm.push(d8, d9, d10, d11);
+ masm.push(d12, d13, d14, d15);
+
+#ifdef DEBUG
+ // Emit stack canaries.
+ masm.movePtr(ImmWord(0xdeadd00d), r23);
+ masm.movePtr(ImmWord(0xdeadd11d), r24);
+ masm.push(r23, r24);
+#endif
+
+ // Common code below attempts to push single registers at a time,
+ // which breaks the stack pointer's 16-byte alignment requirement.
+ // Note that movePtr() is invalid because StackPointer is treated as xzr.
+ //
+ // FIXME: After testing, this entire function should be rewritten to not
+ // use the PseudoStackPointer: since the amount of data pushed is precalculated,
+ // we can just allocate the whole frame header at once and index off sp.
+ // This will save a significant number of instructions where Push() updates sp.
+ masm.Mov(PseudoStackPointer64, sp);
+ masm.SetStackPointer64(PseudoStackPointer64);
+
+ // Save the stack pointer at this point for Baseline OSR.
+ masm.moveStackPtrTo(BaselineFrameReg);
+ // Remember stack depth without padding and arguments.
+ masm.moveStackPtrTo(r19);
+
+ // If constructing, include newTarget in argument vector.
+ {
+ Label noNewTarget;
+ Imm32 constructingToken(CalleeToken_FunctionConstructing);
+ masm.branchTest32(Assembler::Zero, reg_callee, constructingToken, &noNewTarget);
+ masm.add32(Imm32(1), reg_argc);
+ masm.bind(&noNewTarget);
+ }
+
+ // JitFrameLayout is as follows (higher is higher in memory):
+ // N*8 - [ JS argument vector ] (base 16-byte aligned)
+ // 8 - numActualArgs
+ // 8 - calleeToken (16-byte aligned)
+ // 8 - frameDescriptor
+ // 8 - returnAddress (16-byte aligned, pushed by callee)
+
+ // Push the argument vector onto the stack.
+ // WARNING: destructively modifies reg_argv
+ {
+ vixl::UseScratchRegisterScope temps(&masm.asVIXL());
+
+ const ARMRegister tmp_argc = temps.AcquireX();
+ const ARMRegister tmp_sp = temps.AcquireX();
+
+ Label noArguments;
+ Label loopHead;
+
+ masm.movePtr(reg_argc, tmp_argc.asUnsized());
+
+ // sp -= 8
+ // Since we're using PostIndex Str below, this is necessary to avoid overwriting
+ // the SPS mark pushed above.
+ masm.subFromStackPtr(Imm32(8));
+
+ // sp -= 8 * argc
+ masm.Sub(PseudoStackPointer64, PseudoStackPointer64, Operand(tmp_argc, vixl::SXTX, 3));
+
+ // Give sp 16-byte alignment and sync stack pointers.
+ masm.andToStackPtr(Imm32(~0xff));
+ masm.moveStackPtrTo(tmp_sp.asUnsized());
+
+ masm.branchTestPtr(Assembler::Zero, reg_argc, reg_argc, &noArguments);
+
+ // Begin argument-pushing loop.
+ // This could be optimized using Ldp and Stp.
+ {
+ masm.bind(&loopHead);
+
+ // Load an argument from argv, then increment argv by 8.
+ masm.Ldr(x24, MemOperand(ARMRegister(reg_argv, 64), Operand(8), vixl::PostIndex));
+
+ // Store the argument to tmp_sp, then increment tmp_sp by 8.
+ masm.Str(x24, MemOperand(tmp_sp, Operand(8), vixl::PostIndex));
+
+ // Set the condition codes for |cmp tmp_argc, 2| (using the old value).
+ masm.Subs(tmp_argc, tmp_argc, Operand(1));
+
+ // Branch if arguments remain.
+ masm.B(&loopHead, vixl::Condition::ge);
+ }
+
+ masm.bind(&noArguments);
+ }
+ masm.checkStackAlignment();
+
+ // Push the number of actual arguments and the calleeToken.
+ // The result address is used to store the actual number of arguments
+ // without adding an argument to EnterJIT.
+ masm.unboxInt32(Address(reg_vp, 0x0), ip0);
+ masm.push(ip0, reg_callee);
+ masm.checkStackAlignment();
+
+ // Calculate the number of bytes pushed so far.
+ masm.subStackPtrFrom(r19);
+
+ // Push the frameDescriptor.
+ masm.makeFrameDescriptor(r19, JitFrame_Entry, JitFrameLayout::Size());
+ masm.Push(r19);
+
+ Label osrReturnPoint;
+ if (type == EnterJitBaseline) {
+ // Check for OSR.
+ Label notOsr;
+ masm.branchTestPtr(Assembler::Zero, OsrFrameReg, OsrFrameReg, &notOsr);
+
+ // Push return address and previous frame pointer.
+ masm.Adr(ScratchReg2_64, &osrReturnPoint);
+ masm.push(ScratchReg2, BaselineFrameReg);
+
+ // Reserve frame.
+ masm.subFromStackPtr(Imm32(BaselineFrame::Size()));
+ masm.moveStackPtrTo(BaselineFrameReg);
+
+ // Reserve space for locals and stack values.
+ masm.Lsl(w19, ARMRegister(reg_osrNStack, 32), 3); // w19 = num_stack_values * sizeof(Value).
+ masm.subFromStackPtr(r19);
+
+ // Enter exit frame.
+ masm.addPtr(Imm32(BaselineFrame::Size() + BaselineFrame::FramePointerOffset), r19);
+ masm.makeFrameDescriptor(r19, JitFrame_BaselineJS, ExitFrameLayout::Size());
+ masm.asVIXL().Push(x19, xzr); // Push xzr for a fake return address.
+ // No GC things to mark: push a bare token.
+ masm.enterFakeExitFrame(ExitFrameLayoutBareToken);
+
+ masm.push(BaselineFrameReg, reg_code);
+
+ // Initialize the frame, including filling in the slots.
+ masm.setupUnalignedABICall(r19);
+ masm.passABIArg(BaselineFrameReg); // BaselineFrame.
+ masm.passABIArg(reg_osrFrame); // InterpreterFrame.
+ masm.passABIArg(reg_osrNStack);
+ masm.callWithABI(JS_FUNC_TO_DATA_PTR(void*, jit::InitBaselineFrameForOsr));
+
+ masm.pop(r19, BaselineFrameReg);
+ MOZ_ASSERT(r19 != ReturnReg);
+
+ masm.addToStackPtr(Imm32(ExitFrameLayout::SizeWithFooter()));
+ masm.addPtr(Imm32(BaselineFrame::Size()), BaselineFrameReg);
+
+ Label error;
+ masm.branchIfFalseBool(ReturnReg, &error);
+
+ masm.jump(r19);
+
+ // OOM: load error value, discard return address and previous frame
+ // pointer, and return.
+ masm.bind(&error);
+ masm.Add(masm.GetStackPointer64(), BaselineFrameReg64, Operand(2 * sizeof(uintptr_t)));
+ masm.syncStackPtr();
+ masm.moveValue(MagicValue(JS_ION_ERROR), JSReturnOperand);
+ masm.B(&osrReturnPoint);
+
+ masm.bind(&notOsr);
+ masm.movePtr(reg_scope, R1_);
+ }
+
+ // Call function.
+ // Since AArch64 doesn't have the pc register available, the callee must push lr.
+ masm.callJitNoProfiler(reg_code);
+
+ // Baseline OSR will return here.
+ if (type == EnterJitBaseline)
+ masm.bind(&osrReturnPoint);
+
+ // Return back to SP.
+ masm.Pop(r19);
+ masm.Add(masm.GetStackPointer64(), masm.GetStackPointer64(),
+ Operand(x19, vixl::LSR, FRAMESIZE_SHIFT));
+ masm.syncStackPtr();
+ masm.SetStackPointer64(sp);
+
+#ifdef DEBUG
+ // Check that canaries placed on function entry are still present.
+ masm.pop(r24, r23);
+ Label x23OK, x24OK;
+
+ masm.branchPtr(Assembler::Equal, r23, ImmWord(0xdeadd00d), &x23OK);
+ masm.breakpoint();
+ masm.bind(&x23OK);
+
+ masm.branchPtr(Assembler::Equal, r24, ImmWord(0xdeadd11d), &x24OK);
+ masm.breakpoint();
+ masm.bind(&x24OK);
+#endif
+
+ // Restore callee-save floating-point registers.
+ masm.pop(d15, d14, d13, d12);
+ masm.pop(d11, d10, d9, d8);
+
+ // Restore callee-save integer registers.
+ // Also restore x7 (reg_vp) and x30 (lr).
+ masm.pop(r30, r7, r28, r27);
+ masm.pop(r26, r25, r24, r23);
+ masm.pop(r22, r21, r20, r19);
+
+ // Store return value (in JSReturnReg = x2 to just-popped reg_vp).
+ masm.storeValue(JSReturnOperand, Address(reg_vp, 0));
+
+ // Restore old frame pointer.
+ masm.pop(r30, r29);
+
+ // Return using the value popped into x30.
+ masm.abiret();
+
+ Linker linker(masm);
+ AutoFlushICache afc("EnterJIT");
+ JitCode* code = linker.newCode<NoGC>(cx, OTHER_CODE);
+
+#ifdef JS_ION_PERF
+ writePerfSpewerJitCodeProfile(code, "EnterJIT");
+#endif
+
+ return code;
+}
+
+JitCode*
+JitRuntime::generateInvalidator(JSContext* cx)
+{
+ MacroAssembler masm;
+
+ masm.push(r0, r1, r2, r3);
+
+ masm.PushRegsInMask(AllRegs);
+ masm.moveStackPtrTo(r0);
+
+ masm.Sub(x1, masm.GetStackPointer64(), Operand(sizeof(size_t)));
+ masm.Sub(x2, masm.GetStackPointer64(), Operand(sizeof(size_t) + sizeof(void*)));
+ masm.moveToStackPtr(r2);
+
+ masm.setupUnalignedABICall(r10);
+ masm.passABIArg(r0);
+ masm.passABIArg(r1);
+ masm.passABIArg(r2);
+
+ masm.callWithABI(JS_FUNC_TO_DATA_PTR(void*, InvalidationBailout));
+
+ masm.pop(r2, r1);
+
+ masm.Add(masm.GetStackPointer64(), masm.GetStackPointer64(), x1);
+ masm.Add(masm.GetStackPointer64(), masm.GetStackPointer64(),
+ Operand(sizeof(InvalidationBailoutStack)));
+ masm.syncStackPtr();
+
+ JitCode* bailoutTail = cx->runtime()->jitRuntime()->getBailoutTail();
+ masm.branch(bailoutTail);
+
+ Linker linker(masm);
+ AutoFlushICache afc("Invalidator");
+ return linker.newCode<NoGC>(cx, OTHER_CODE);
+}
+
+JitCode*
+JitRuntime::generateArgumentsRectifier(JSContext* cx, void** returnAddrOut)
+{
+ MacroAssembler masm;
+
+ // Save the return address for later.
+ masm.push(lr);
+
+ // Load the information that the rectifier needs from the stack.
+ masm.Ldr(w0, MemOperand(masm.GetStackPointer64(), RectifierFrameLayout::offsetOfNumActualArgs()));
+ masm.Ldr(x1, MemOperand(masm.GetStackPointer64(), RectifierFrameLayout::offsetOfCalleeToken()));
+
+ // Extract a JSFunction pointer from the callee token and keep the
+ // intermediary to avoid later recalculation.
+ masm.And(x5, x1, Operand(CalleeTokenMask));
+
+ // Get the arguments from the function object.
+ masm.Ldrh(x6, MemOperand(x5, JSFunction::offsetOfNargs()));
+
+ static_assert(CalleeToken_FunctionConstructing == 0x1, "Constructing must be low-order bit");
+ masm.And(x4, x1, Operand(CalleeToken_FunctionConstructing));
+ masm.Add(x7, x6, x4);
+
+ // Calculate the position that our arguments are at before sp gets modified.
+ MOZ_ASSERT(ArgumentsRectifierReg == r8, "x8 used for argc in Arguments Rectifier");
+ masm.Add(x3, masm.GetStackPointer64(), Operand(x8, vixl::LSL, 3));
+ masm.Add(x3, x3, Operand(sizeof(RectifierFrameLayout)));
+
+ // Pad to a multiple of 16 bytes. This neglects the |this| value,
+ // which will also be pushed, because the rest of the frame will
+ // round off that value. See pushes of |argc|, |callee| and |desc| below.
+ Label noPadding;
+ masm.Tbnz(x7, 0, &noPadding);
+ masm.asVIXL().Push(xzr);
+ masm.Add(x7, x7, Operand(1));
+ masm.bind(&noPadding);
+
+ {
+ Label notConstructing;
+ masm.Cbz(x4, &notConstructing);
+
+ // new.target lives at the end of the pushed args
+ // NB: The arg vector holder starts at the beginning of the last arg,
+ // add a value to get to argv[argc]
+ masm.loadPtr(Address(r3, sizeof(Value)), r4);
+ masm.Push(r4);
+
+ masm.bind(&notConstructing);
+ }
+
+ // Calculate the number of undefineds that need to be pushed.
+ masm.Sub(w2, w6, w8);
+
+ // Put an undefined in a register so it can be pushed.
+ masm.moveValue(UndefinedValue(), r4);
+
+ // Push undefined N times.
+ {
+ Label undefLoopTop;
+ masm.bind(&undefLoopTop);
+ masm.Push(r4);
+ masm.Subs(w2, w2, Operand(1));
+ masm.B(&undefLoopTop, Assembler::NonZero);
+ }
+
+ // Arguments copy loop. Copy for x8 >= 0 to include |this|.
+ {
+ Label copyLoopTop;
+ masm.bind(&copyLoopTop);
+ masm.Ldr(x4, MemOperand(x3, -sizeof(Value), vixl::PostIndex));
+ masm.Push(r4);
+ masm.Subs(x8, x8, Operand(1));
+ masm.B(&copyLoopTop, Assembler::NotSigned);
+ }
+
+ // Fix up the size of the stack frame. +1 accounts for |this|.
+ masm.Add(x6, x7, Operand(1));
+ masm.Lsl(x6, x6, 3);
+
+ // Make that into a frame descriptor.
+ masm.makeFrameDescriptor(r6, JitFrame_Rectifier, JitFrameLayout::Size());
+
+ masm.push(r0, // Number of actual arguments.
+ r1, // Callee token.
+ r6); // Frame descriptor.
+
+ // Load the address of the code that is getting called.
+ masm.Ldr(x3, MemOperand(x5, JSFunction::offsetOfNativeOrScript()));
+ masm.loadBaselineOrIonRaw(r3, r3, nullptr);
+ uint32_t returnOffset = masm.callJitNoProfiler(r3);
+
+ // Clean up!
+ // Get the size of the stack frame, and clean up the later fixed frame.
+ masm.Ldr(x4, MemOperand(masm.GetStackPointer64(), 24, vixl::PostIndex));
+
+ // Now that the size of the stack frame sans the fixed frame has been loaded,
+ // add that onto the stack pointer.
+ masm.Add(masm.GetStackPointer64(), masm.GetStackPointer64(),
+ Operand(x4, vixl::LSR, FRAMESIZE_SHIFT));
+
+ // Pop the return address from earlier and branch.
+ masm.ret();
+
+ Linker linker(masm);
+ AutoFlushICache afc("ArgumentsRectifier");
+ JitCode* code = linker.newCode<NoGC>(cx, OTHER_CODE);
+
+ if (returnAddrOut)
+ *returnAddrOut = (void*) (code->raw() + returnOffset);
+
+ return code;
+}
+
+static void
+PushBailoutFrame(MacroAssembler& masm, uint32_t frameClass, Register spArg)
+{
+ // 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
+
+ // We don't have to push everything, but this is likely easier.
+ // Setting regs_.
+ masm.subFromStackPtr(Imm32(Registers::TotalPhys * sizeof(void*)));
+ for (uint32_t i = 0; i < Registers::TotalPhys; i += 2) {
+ masm.Stp(ARMRegister::XRegFromCode(i),
+ ARMRegister::XRegFromCode(i + 1),
+ MemOperand(masm.GetStackPointer64(), i * sizeof(void*)));
+ }
+
+ // 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.
+ masm.subFromStackPtr(Imm32(FloatRegisters::TotalPhys * sizeof(double)));
+ for (uint32_t i = 0; i < FloatRegisters::TotalPhys; i += 2) {
+ masm.Stp(ARMFPRegister::DRegFromCode(i),
+ ARMFPRegister::DRegFromCode(i + 1),
+ MemOperand(masm.GetStackPointer64(), i * sizeof(void*)));
+ }
+
+ // 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.Mov(x9, frameClass);
+
+ // 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.push(r30, r9);
+ masm.moveStackPtrTo(spArg);
+}
+
+static void
+GenerateBailoutThunk(JSContext* cx, MacroAssembler& masm, uint32_t frameClass)
+{
+ 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.
+ // Make space for the BaselineBailoutInfo* outparam.
+ const int sizeOfBailoutInfo = sizeof(void*) * 2;
+ masm.reserveStack(sizeOfBailoutInfo);
+ masm.moveStackPtrTo(r1);
+
+ masm.setupUnalignedABICall(r2);
+ masm.passABIArg(r0);
+ masm.passABIArg(r1);
+ masm.callWithABI(JS_FUNC_TO_DATA_PTR(void*, Bailout));
+
+ masm.Ldr(x2, MemOperand(masm.GetStackPointer64(), 0));
+ masm.addToStackPtr(Imm32(sizeOfBailoutInfo));
+
+ static const uint32_t BailoutDataSize = sizeof(void*) * Registers::Total +
+ sizeof(double) * FloatRegisters::TotalPhys;
+
+ if (frameClass == NO_FRAME_SIZE_CLASS_ID) {
+ vixl::UseScratchRegisterScope temps(&masm.asVIXL());
+ const ARMRegister scratch64 = temps.AcquireX();
+
+ masm.Ldr(scratch64, MemOperand(masm.GetStackPointer64(), sizeof(uintptr_t)));
+ masm.addToStackPtr(Imm32(BailoutDataSize + 32));
+ masm.addToStackPtr(scratch64.asUnsized());
+ } else {
+ uint32_t frameSize = FrameSizeClass::FromClass(frameClass).frameSize();
+ masm.addToStackPtr(Imm32(frameSize + BailoutDataSize + sizeof(void*)));
+ }
+
+ // Jump to shared bailout tail. The BailoutInfo pointer has to be in r9.
+ JitCode* bailoutTail = cx->runtime()->jitRuntime()->getBailoutTail();
+ masm.branch(bailoutTail);
+}
+
+JitCode*
+JitRuntime::generateBailoutTable(JSContext* cx, uint32_t frameClass)
+{
+ // FIXME: Implement.
+ MacroAssembler masm;
+ masm.breakpoint();
+ Linker linker(masm);
+ AutoFlushICache afc("BailoutTable");
+ return linker.newCode<NoGC>(cx, OTHER_CODE);
+}
+
+JitCode*
+JitRuntime::generateBailoutHandler(JSContext* cx)
+{
+ MacroAssembler masm(cx);
+ GenerateBailoutThunk(cx, masm, NO_FRAME_SIZE_CLASS_ID);
+
+#ifdef JS_ION_PERF
+ writePerfSpewerJitCodeProfile(code, "BailoutHandler");
+#endif
+
+ Linker linker(masm);
+ AutoFlushICache afc("BailoutHandler");
+ return linker.newCode<NoGC>(cx, OTHER_CODE);
+}
+
+JitCode*
+JitRuntime::generateVMWrapper(JSContext* cx, const VMFunction& f)
+{
+ MOZ_ASSERT(functionWrappers_);
+ MOZ_ASSERT(functionWrappers_->initialized());
+ VMWrapperMap::AddPtr p = functionWrappers_->lookupForAdd(&f);
+ if (p)
+ return p->value();
+
+ MacroAssembler masm(cx);
+
+ // Avoid conflicts with argument registers while discarding the result after
+ // the function call.
+ AllocatableGeneralRegisterSet regs(Register::Codes::WrapperMask);
+
+ // Wrapper register set is a superset of the Volatile register set.
+ JS_STATIC_ASSERT((Register::Codes::VolatileMask & ~Register::Codes::WrapperMask) == 0);
+
+ // Unlike on other platforms, it is the responsibility of the VM *callee* to
+ // push the return address, while the caller must ensure that the address
+ // is stored in lr on entry. This allows the VM wrapper to work with both direct
+ // calls and tail calls.
+ masm.push(lr);
+
+ // First argument is the JSContext.
+ Register reg_cx = IntArgReg0;
+ regs.take(reg_cx);
+
+ // Stack is:
+ // ... frame ...
+ // +12 [args]
+ // +8 descriptor
+ // +0 returnAddress (pushed by this function, caller sets as lr)
+ //
+ // We're aligned to an exit frame, so link it up.
+ masm.enterExitFrame(&f);
+ masm.loadJSContext(reg_cx);
+
+ // Save the current stack pointer as the base for copying arguments.
+ Register argsBase = InvalidReg;
+ if (f.explicitArgs) {
+ // argsBase can't be an argument register. Bad things would happen if
+ // the MoveResolver didn't throw an assertion failure first.
+ argsBase = r8;
+ regs.take(argsBase);
+ masm.Add(ARMRegister(argsBase, 64), masm.GetStackPointer64(),
+ Operand(ExitFrameLayout::SizeWithFooter()));
+ }
+
+ // Reserve space for any outparameter.
+ Register outReg = InvalidReg;
+ switch (f.outParam) {
+ case Type_Value:
+ outReg = regs.takeAny();
+ masm.reserveStack(sizeof(Value));
+ masm.moveStackPtrTo(outReg);
+ break;
+
+ case Type_Handle:
+ outReg = regs.takeAny();
+ masm.PushEmptyRooted(f.outParamRootType);
+ masm.moveStackPtrTo(outReg);
+ break;
+
+ case Type_Int32:
+ case Type_Bool:
+ outReg = regs.takeAny();
+ masm.reserveStack(sizeof(int64_t));
+ masm.moveStackPtrTo(outReg);
+ break;
+
+ case Type_Double:
+ outReg = regs.takeAny();
+ masm.reserveStack(sizeof(double));
+ masm.moveStackPtrTo(outReg);
+ break;
+
+ case Type_Pointer:
+ outReg = regs.takeAny();
+ masm.reserveStack(sizeof(uintptr_t));
+ masm.moveStackPtrTo(outReg);
+ break;
+
+ default:
+ MOZ_ASSERT(f.outParam == Type_Void);
+ break;
+ }
+
+ if (!generateTLEnterVM(cx, masm, f))
+ return nullptr;
+
+ masm.setupUnalignedABICall(regs.getAny());
+ masm.passABIArg(reg_cx);
+
+ size_t argDisp = 0;
+
+ // Copy arguments.
+ for (uint32_t explicitArg = 0; explicitArg < f.explicitArgs; explicitArg++) {
+ MoveOperand from;
+ switch (f.argProperties(explicitArg)) {
+ case VMFunction::WordByValue:
+ masm.passABIArg(MoveOperand(argsBase, argDisp),
+ (f.argPassedInFloatReg(explicitArg) ? MoveOp::DOUBLE : MoveOp::GENERAL));
+ argDisp += sizeof(void*);
+ break;
+
+ case VMFunction::WordByRef:
+ masm.passABIArg(MoveOperand(argsBase, argDisp, MoveOperand::EFFECTIVE_ADDRESS),
+ MoveOp::GENERAL);
+ argDisp += sizeof(void*);
+ break;
+
+ case VMFunction::DoubleByValue:
+ case VMFunction::DoubleByRef:
+ MOZ_CRASH("NYI: AArch64 callVM should not be used with 128bit values.");
+ }
+ }
+
+ // Copy the semi-implicit outparam, if any.
+ // It is not a C++-abi outparam, which would get passed in the
+ // outparam register, but a real parameter to the function, which
+ // was stack-allocated above.
+ if (outReg != InvalidReg)
+ masm.passABIArg(outReg);
+
+ masm.callWithABI(f.wrapped);
+
+ if (!generateTLExitVM(cx, masm, f))
+ return nullptr;
+
+ // SP is used to transfer stack across call boundaries.
+ if (!masm.GetStackPointer64().Is(vixl::sp))
+ masm.Mov(masm.GetStackPointer64(), vixl::sp);
+
+ // 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;
+ default:
+ MOZ_CRASH("unknown failure kind");
+ }
+
+ // Load the outparam and free any allocated stack.
+ switch (f.outParam) {
+ case Type_Value:
+ masm.Ldr(ARMRegister(JSReturnReg, 64), MemOperand(masm.GetStackPointer64()));
+ masm.freeStack(sizeof(Value));
+ break;
+
+ case Type_Handle:
+ masm.popRooted(f.outParamRootType, ReturnReg, JSReturnOperand);
+ break;
+
+ case Type_Int32:
+ masm.Ldr(ARMRegister(ReturnReg, 32), MemOperand(masm.GetStackPointer64()));
+ masm.freeStack(sizeof(int64_t));
+ break;
+
+ case Type_Bool:
+ masm.Ldrb(ARMRegister(ReturnReg, 32), MemOperand(masm.GetStackPointer64()));
+ masm.freeStack(sizeof(int64_t));
+ break;
+
+ case Type_Double:
+ MOZ_ASSERT(cx->runtime()->jitSupportsFloatingPoint);
+ masm.Ldr(ARMFPRegister(ReturnDoubleReg, 64), MemOperand(masm.GetStackPointer64()));
+ masm.freeStack(sizeof(double));
+ break;
+
+ case Type_Pointer:
+ masm.Ldr(ARMRegister(ReturnReg, 64), MemOperand(masm.GetStackPointer64()));
+ masm.freeStack(sizeof(uintptr_t));
+ break;
+
+ default:
+ MOZ_ASSERT(f.outParam == Type_Void);
+ break;
+ }
+
+ masm.leaveExitFrame();
+ masm.retn(Imm32(sizeof(ExitFrameLayout) +
+ f.explicitStackSlots() * sizeof(void*) +
+ f.extraValuesToPop * sizeof(Value)));
+
+ Linker linker(masm);
+ AutoFlushICache afc("VMWrapper");
+ JitCode* wrapper = linker.newCode<NoGC>(cx, OTHER_CODE);
+ if (!wrapper)
+ return nullptr;
+
+#ifdef JS_ION_PERF
+ writePerfSpewerJitCodeProfile(wrapper, "VMWrapper");
+#endif
+
+ // linker.newCode may trigger a GC and sweep functionWrappers_ so we have to
+ // use relookupOrAdd instead of add.
+ if (!functionWrappers_->relookupOrAdd(p, &f, wrapper))
+ return nullptr;
+
+ return wrapper;
+}
+
+JitCode*
+JitRuntime::generatePreBarrier(JSContext* cx, MIRType type)
+{
+ MacroAssembler masm(cx);
+
+ LiveRegisterSet regs = LiveRegisterSet(GeneralRegisterSet(Registers::VolatileMask),
+ FloatRegisterSet(FloatRegisters::VolatileMask));
+
+ // Also preserve the return address.
+ regs.add(lr);
+
+ masm.PushRegsInMask(regs);
+
+ MOZ_ASSERT(PreBarrierReg == r1);
+ masm.movePtr(ImmPtr(cx->runtime()), r3);
+
+ masm.setupUnalignedABICall(r0);
+ masm.passABIArg(r3);
+ masm.passABIArg(PreBarrierReg);
+ masm.callWithABI(IonMarkFunction(type));
+
+ // Pop the volatile regs and restore LR.
+ masm.PopRegsInMask(regs);
+
+ masm.abiret();
+
+ Linker linker(masm);
+ AutoFlushICache afc("PreBarrier");
+ return linker.newCode<NoGC>(cx, OTHER_CODE);
+}
+
+typedef bool (*HandleDebugTrapFn)(JSContext*, BaselineFrame*, uint8_t*, bool*);
+static const VMFunction HandleDebugTrapInfo =
+ FunctionInfo<HandleDebugTrapFn>(HandleDebugTrap, "HandleDebugTrap");
+
+JitCode*
+JitRuntime::generateDebugTrapHandler(JSContext* cx)
+{
+ MacroAssembler masm(cx);
+#ifndef JS_USE_LINK_REGISTER
+ // The first value contains the return addres,
+ // which we pull into ICTailCallReg for tail calls.
+ masm.setFramePushed(sizeof(intptr_t));
+#endif
+
+ Register scratch1 = r0;
+ Register scratch2 = r1;
+
+ // Load BaselineFrame pointer into scratch1.
+ masm.Sub(ARMRegister(scratch1, 64), BaselineFrameReg64, Operand(BaselineFrame::Size()));
+
+ // Enter a stub frame and call the HandleDebugTrap VM function. Ensure the
+ // stub frame has a nullptr ICStub pointer, since this pointer is marked
+ // during GC.
+ masm.movePtr(ImmPtr(nullptr), ICStubReg);
+ EmitBaselineEnterStubFrame(masm, scratch2);
+
+ JitCode* code = cx->runtime()->jitRuntime()->getVMWrapper(HandleDebugTrapInfo);
+ if (!code)
+ return nullptr;
+
+ masm.asVIXL().Push(vixl::lr, ARMRegister(scratch1, 64));
+ EmitBaselineCallVM(code, masm);
+
+ EmitBaselineLeaveStubFrame(masm);
+
+ // If the stub returns |true|, we have to perform a forced return (return
+ // from the JS frame). If the stub returns |false|, just return from the
+ // trap stub so that execution continues at the current pc.
+ Label forcedReturn;
+ masm.branchTest32(Assembler::NonZero, ReturnReg, ReturnReg, &forcedReturn);
+ masm.abiret();
+
+ masm.bind(&forcedReturn);
+ masm.loadValue(Address(BaselineFrameReg, BaselineFrame::reverseOffsetOfReturnValue()),
+ JSReturnOperand);
+ masm.Mov(masm.GetStackPointer64(), BaselineFrameReg64);
+
+ masm.pop(BaselineFrameReg, lr);
+ masm.syncStackPtr();
+ masm.abiret();
+
+ Linker linker(masm);
+ AutoFlushICache afc("DebugTrapHandler");
+ JitCode* codeDbg = linker.newCode<NoGC>(cx, OTHER_CODE);
+
+#ifdef JS_ION_PERF
+ writePerfSpewerJitCodeProfile(codeDbg, "DebugTrapHandler");
+#endif
+
+ return codeDbg;
+}
+
+JitCode*
+JitRuntime::generateExceptionTailStub(JSContext* cx, void* handler)
+{
+ MacroAssembler masm(cx);
+
+ masm.handleFailureWithHandlerTail(handler);
+
+ Linker linker(masm);
+ AutoFlushICache afc("ExceptionTailStub");
+ JitCode* code = linker.newCode<NoGC>(cx, OTHER_CODE);
+
+#ifdef JS_ION_PERF
+ writePerfSpewerJitCodeProfile(code, "ExceptionTailStub");
+#endif
+
+ return code;
+}
+
+JitCode*
+JitRuntime::generateBailoutTailStub(JSContext* cx)
+{
+ MacroAssembler masm(cx);
+
+ masm.generateBailoutTail(r1, r2);
+
+ Linker linker(masm);
+ AutoFlushICache afc("BailoutTailStub");
+ JitCode* code = linker.newCode<NoGC>(cx, OTHER_CODE);
+
+#ifdef JS_ION_PERF
+ writePerfSpewerJitCodeProfile(code, "BailoutTailStub");
+#endif
+
+ return code;
+}
+JitCode*
+JitRuntime::generateProfilerExitFrameTailStub(JSContext* cx)
+{
+ MacroAssembler masm;
+
+ Register scratch1 = r8;
+ Register scratch2 = r9;
+ Register scratch3 = r10;
+ Register scratch4 = r11;
+
+ //
+ // 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:
+ //
+ // <Baseline-Or-Ion>
+ // ^
+ // |
+ // ^--- Ion
+ // |
+ // ^--- Baseline Stub <---- Baseline
+ // |
+ // ^--- Argument Rectifier
+ // | ^
+ // | |
+ // | ^--- Ion
+ // | |
+ // | ^--- Baseline Stub <---- Baseline
+ // |
+ // ^--- Entry Frame (From C++)
+ //
+ Register actReg = scratch4;
+ AbsoluteAddress activationAddr(GetJitContext()->runtime->addressOfProfilingActivation());
+ masm.loadPtr(activationAddr, 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.branchStackPtr(Assembler::Equal, 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(masm.getStackPointer(), JitFrameLayout::offsetOfDescriptor()), scratch1);
+
+ // Going into the conditionals, we will have:
+ // FrameDescriptor.size in scratch1
+ // FrameDescriptor.type in scratch2
+ masm.and32(Imm32((1 << FRAMETYPE_BITS) - 1), scratch1, scratch2);
+ 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_IonAccessorIC;
+ Label handle_Entry;
+ Label end;
+
+ masm.branch32(Assembler::Equal, scratch2, Imm32(JitFrame_IonJS), &handle_IonJS);
+ masm.branch32(Assembler::Equal, scratch2, Imm32(JitFrame_BaselineJS), &handle_IonJS);
+ masm.branch32(Assembler::Equal, scratch2, Imm32(JitFrame_BaselineStub), &handle_BaselineStub);
+ masm.branch32(Assembler::Equal, scratch2, Imm32(JitFrame_Rectifier), &handle_Rectifier);
+ masm.branch32(Assembler::Equal, scratch2, Imm32(JitFrame_IonAccessorIC), &handle_IonAccessorIC);
+ masm.branch32(Assembler::Equal, scratch2, Imm32(JitFrame_Entry), &handle_Entry);
+
+ masm.assumeUnreachable("Invalid caller frame type when exiting from Ion frame.");
+
+ //
+ // JitFrame_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(masm.getStackPointer(), JitFrameLayout::offsetOfReturnAddress()),
+ scratch2);
+ masm.storePtr(scratch2, lastProfilingCallSite);
+
+ // Store return frame in lastProfilingFrame.
+ // scratch2 := masm.getStackPointer() + Descriptor.size*1 + JitFrameLayout::Size();
+ masm.addPtr(masm.getStackPointer(), scratch1, scratch2);
+ masm.syncStackPtr();
+ masm.addPtr(Imm32(JitFrameLayout::Size()), scratch2, scratch2);
+ masm.storePtr(scratch2, lastProfilingFrame);
+ masm.ret();
+ }
+
+ //
+ // JitFrame_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.addPtr(masm.getStackPointer(), scratch1, scratch3);
+ masm.syncStackPtr();
+ 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();
+ }
+
+
+ //
+ // JitFrame_Rectifier
+ //
+ // The rectifier frame can be preceded by either an IonJS or a
+ // BaselineStub frame.
+ //
+ // Stack layout if caller of rectifier was Ion:
+ //
+ // 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.addPtr(masm.getStackPointer(), scratch1, scratch2);
+ masm.syncStackPtr();
+ masm.add32(Imm32(JitFrameLayout::Size()), scratch2);
+ masm.loadPtr(Address(scratch2, RectifierFrameLayout::offsetOfDescriptor()), scratch3);
+ masm.rshiftPtr(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
+
+ // Check for either Ion or BaselineStub frame.
+ Label handle_Rectifier_BaselineStub;
+ masm.branch32(Assembler::NotEqual, scratch3, Imm32(JitFrame_IonJS),
+ &handle_Rectifier_BaselineStub);
+
+ // 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.addPtr(scratch2, scratch1, scratch3);
+ masm.add32(Imm32(RectifierFrameLayout::Size()), scratch3);
+ masm.storePtr(scratch3, lastProfilingFrame);
+ masm.ret();
+
+ // Handle Rectifier <- BaselineStub <- BaselineJS
+ masm.bind(&handle_Rectifier_BaselineStub);
+#ifdef DEBUG
+ {
+ Label checkOk;
+ masm.branch32(Assembler::Equal, scratch3, Imm32(JitFrame_BaselineStub), &checkOk);
+ masm.assumeUnreachable("Unrecognized frame preceding baselineStub.");
+ masm.bind(&checkOk);
+ }
+#endif
+ masm.addPtr(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();
+ }
+
+ // JitFrame_IonAccessorIC
+ //
+ // The caller is always an IonJS frame.
+ //
+ // Ion-Descriptor
+ // Ion-ReturnAddr
+ // ... ion frame data ... |- AccFrame-Descriptor.Size
+ // StubCode |
+ // AccFrame-Descriptor |- IonAccessorICFrameLayout::Size()
+ // AccFrame-ReturnAddr |
+ // ... accessor frame data & args ... |- Descriptor.Size
+ // ActualArgc |
+ // CalleeToken |- JitFrameLayout::Size()
+ // Descriptor |
+ // FP -----> ReturnAddr |
+ masm.bind(&handle_IonAccessorIC);
+ {
+ // scratch2 := StackPointer + Descriptor.size + JitFrameLayout::Size()
+ masm.addPtr(masm.getStackPointer(), scratch1, scratch2);
+ masm.syncStackPtr();
+ masm.addPtr(Imm32(JitFrameLayout::Size()), scratch2);
+
+ // scratch3 := AccFrame-Descriptor.Size
+ masm.loadPtr(Address(scratch2, IonAccessorICFrameLayout::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(JitFrame_IonJS), &checkOk);
+ masm.assumeUnreachable("IonAccessorIC frame must be preceded by IonJS frame");
+ masm.bind(&checkOk);
+ }
+#endif
+ masm.rshiftPtr(Imm32(FRAMESIZE_SHIFT), scratch3);
+
+ // lastProfilingCallSite := AccFrame-ReturnAddr
+ masm.loadPtr(Address(scratch2, IonAccessorICFrameLayout::offsetOfReturnAddress()), scratch1);
+ masm.storePtr(scratch1, lastProfilingCallSite);
+
+ // lastProfilingFrame := AccessorFrame + AccFrame-Descriptor.Size +
+ // IonAccessorICFrameLayout::Size()
+ masm.addPtr(scratch2, scratch3, scratch1);
+ masm.addPtr(Imm32(IonAccessorICFrameLayout::Size()), scratch1);
+ masm.storePtr(scratch1, lastProfilingFrame);
+ masm.ret();
+ }
+
+ //
+ // JitFrame_Entry
+ //
+ // If at an entry frame, store null into both fields.
+ //
+ masm.bind(&handle_Entry);
+ {
+ masm.movePtr(ImmPtr(nullptr), scratch1);
+ masm.storePtr(scratch1, lastProfilingCallSite);
+ masm.storePtr(scratch1, lastProfilingFrame);
+ masm.ret();
+ }
+
+ Linker linker(masm);
+ AutoFlushICache afc("ProfilerExitFrameTailStub");
+ JitCode* code = linker.newCode<NoGC>(cx, OTHER_CODE);
+
+#ifdef JS_ION_PERF
+ writePerfSpewerJitCodeProfile(code, "ProfilerExitFrameStub");
+#endif
+
+ return code;
+}