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-rw-r--r--js/src/jit/arm64/Trampoline-arm64.cpp840
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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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+++ b/js/src/jit/arm64/Trampoline-arm64.cpp
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+/* -*- 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/arm64/SharedICHelpers-arm64.h"
+#include "jit/Bailouts.h"
+#include "jit/BaselineFrame.h"
+#include "jit/CalleeToken.h"
+#include "jit/JitFrames.h"
+#include "jit/JitRuntime.h"
+#include "jit/PerfSpewer.h"
+#include "jit/VMFunctions.h"
+#include "vm/JitActivation.h" // js::jit::JitActivation
+#include "vm/JSContext.h"
+
+#include "jit/MacroAssembler-inl.h"
+
+using namespace js;
+using namespace js::jit;
+
+/* 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
+ */
+void JitRuntime::generateEnterJIT(JSContext* cx, MacroAssembler& masm) {
+ AutoCreatedBy acb(masm, "JitRuntime::generateEnterJIT");
+
+ enterJITOffset_ = startTrampolineCode(masm);
+
+ 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.
+
+ static_assert(OsrFrameReg == IntArgReg3);
+
+ // During the pushes below, use the normal stack pointer.
+ masm.SetStackPointer64(sp);
+
+ // Save return address and old frame pointer; set new frame pointer.
+ masm.push(r30, r29);
+ 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);
+
+ // 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 - calleeToken
+ // 8 - frameDescriptor (16-byte aligned)
+ // 8 - returnAddress
+ // 8 - frame pointer (16-byte aligned, pushed by callee)
+
+ // Touch frame incrementally (a requirement for Windows).
+ //
+ // Use already saved callee-save registers r20 and r21 as temps.
+ //
+ // This has to be done outside the ScratchRegisterScope, as the temps are
+ // under demand inside the touchFrameValues call.
+
+ // Give sp 16-byte alignment and sync stack pointers.
+ masm.andToStackPtr(Imm32(~0xf));
+ // We needn't worry about the Gecko Profiler mark because touchFrameValues
+ // touches in large increments.
+ masm.touchFrameValues(reg_argc, r20, r21);
+ // Restore stack pointer, preserved above.
+ masm.moveToStackPtr(r19);
+
+ // 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 Gecko Profiler 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(~0xf));
+ 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));
+
+ // Decrement tmp_argc and set the condition codes for the new value.
+ masm.Subs(tmp_argc, tmp_argc, Operand(1));
+
+ // Branch if arguments remain.
+ masm.B(&loopHead, vixl::Condition::NonZero);
+ }
+
+ masm.bind(&noArguments);
+ }
+ masm.checkStackAlignment();
+
+ // Push the calleeToken and the frame descriptor.
+ // The result address is used to store the actual number of arguments
+ // without adding an argument to EnterJIT.
+ {
+ vixl::UseScratchRegisterScope temps(&masm.asVIXL());
+ MOZ_ASSERT(temps.IsAvailable(ScratchReg64)); // ip0
+ temps.Exclude(ScratchReg64);
+ Register scratch = ScratchReg64.asUnsized();
+ masm.push(reg_callee);
+
+ // Push the descriptor.
+ masm.unboxInt32(Address(reg_vp, 0x0), scratch);
+ masm.PushFrameDescriptorForJitCall(FrameType::CppToJSJit, scratch, scratch);
+ }
+ masm.checkStackAlignment();
+
+ Label osrReturnPoint;
+ {
+ // Check for Interpreter -> Baseline OSR.
+
+ AllocatableGeneralRegisterSet regs(GeneralRegisterSet::All());
+ MOZ_ASSERT(!regs.has(FramePointer));
+ regs.take(OsrFrameReg);
+ regs.take(reg_code);
+ regs.take(reg_osrNStack);
+ MOZ_ASSERT(!regs.has(ReturnReg), "ReturnReg matches reg_code");
+
+ Label notOsr;
+ masm.branchTestPtr(Assembler::Zero, OsrFrameReg, OsrFrameReg, &notOsr);
+
+ Register scratch = regs.takeAny();
+
+ // Frame prologue.
+ masm.Adr(ARMRegister(scratch, 64), &osrReturnPoint);
+ masm.push(scratch, FramePointer);
+ masm.moveStackPtrTo(FramePointer);
+
+ // Reserve frame.
+ masm.subFromStackPtr(Imm32(BaselineFrame::Size()));
+
+ Register framePtrScratch = regs.takeAny();
+ masm.touchFrameValues(reg_osrNStack, scratch, framePtrScratch);
+ masm.moveStackPtrTo(framePtrScratch);
+
+ // Reserve space for locals and stack values.
+ // scratch = num_stack_values * sizeof(Value).
+ masm.Lsl(ARMRegister(scratch, 32), ARMRegister(reg_osrNStack, 32), 3);
+ masm.subFromStackPtr(scratch);
+
+ // Enter exit frame.
+ masm.pushFrameDescriptor(FrameType::BaselineJS);
+ masm.push(xzr); // Push xzr for a fake return address.
+ masm.push(FramePointer);
+ // No GC things to mark: push a bare token.
+ masm.loadJSContext(scratch);
+ masm.enterFakeExitFrame(scratch, scratch, ExitFrameType::Bare);
+
+ masm.push(reg_code);
+
+ // Initialize the frame, including filling in the slots.
+ using Fn = bool (*)(BaselineFrame * frame, InterpreterFrame * interpFrame,
+ uint32_t numStackValues);
+ masm.setupUnalignedABICall(r19);
+ masm.passABIArg(framePtrScratch); // BaselineFrame.
+ masm.passABIArg(reg_osrFrame); // InterpreterFrame.
+ masm.passABIArg(reg_osrNStack);
+ masm.callWithABI<Fn, jit::InitBaselineFrameForOsr>(
+ MoveOp::GENERAL, CheckUnsafeCallWithABI::DontCheckHasExitFrame);
+
+ masm.pop(scratch);
+ MOZ_ASSERT(scratch != ReturnReg);
+
+ masm.addToStackPtr(Imm32(ExitFrameLayout::SizeWithFooter()));
+
+ Label error;
+ masm.branchIfFalseBool(ReturnReg, &error);
+
+ // If OSR-ing, then emit instrumentation for setting lastProfilerFrame
+ // if profiler instrumentation is enabled.
+ {
+ Label skipProfilingInstrumentation;
+ AbsoluteAddress addressOfEnabled(
+ cx->runtime()->geckoProfiler().addressOfEnabled());
+ masm.branch32(Assembler::Equal, addressOfEnabled, Imm32(0),
+ &skipProfilingInstrumentation);
+ masm.profilerEnterFrame(FramePointer, regs.getAny());
+ masm.bind(&skipProfilingInstrumentation);
+ }
+
+ masm.jump(scratch);
+
+ // OOM: frame epilogue, load error value, discard return address and return.
+ masm.bind(&error);
+ masm.moveToStackPtr(FramePointer);
+ masm.pop(FramePointer);
+ masm.addToStackPtr(Imm32(sizeof(uintptr_t))); // Return address.
+ masm.syncStackPtr();
+ masm.moveValue(MagicValue(JS_ION_ERROR), JSReturnOperand);
+ masm.B(&osrReturnPoint);
+
+ masm.bind(&notOsr);
+ masm.movePtr(reg_scope, R1_);
+ }
+
+ // The callee will push the return address and frame pointer on the stack,
+ // thus we check that the stack would be aligned once the call is complete.
+ masm.assertStackAlignment(JitStackAlignment, 2 * sizeof(uintptr_t));
+
+ // Call function.
+ // Since AArch64 doesn't have the pc register available, the callee must push
+ // lr.
+ masm.callJitNoProfiler(reg_code);
+
+ // Interpreter -> Baseline OSR will return here.
+ masm.bind(&osrReturnPoint);
+
+ // Discard arguments and padding. Set sp to the address of the saved
+ // registers. In debug builds we have to include the two stack canaries
+ // checked below.
+#ifdef DEBUG
+ static constexpr size_t SavedRegSize = 22 * sizeof(void*);
+#else
+ static constexpr size_t SavedRegSize = 20 * sizeof(void*);
+#endif
+ masm.computeEffectiveAddress(Address(FramePointer, -int32_t(SavedRegSize)),
+ masm.getStackPointer());
+
+ 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(r29, r30);
+
+ // Return using the value popped into x30.
+ masm.abiret();
+
+ // Reset stack pointer.
+ masm.SetStackPointer64(PseudoStackPointer64);
+}
+
+// static
+mozilla::Maybe<::JS::ProfilingFrameIterator::RegisterState>
+JitRuntime::getCppEntryRegisters(JitFrameLayout* frameStackAddress) {
+ // Not supported, or not implemented yet.
+ // TODO: Implement along with the corresponding stack-walker changes, in
+ // coordination with the Gecko Profiler, see bug 1635987 and follow-ups.
+ return mozilla::Nothing{};
+}
+
+static void PushRegisterDump(MacroAssembler& masm) {
+ const LiveRegisterSet First28GeneralRegisters = LiveRegisterSet(
+ GeneralRegisterSet(Registers::AllMask &
+ ~(1 << 31 | 1 << 30 | 1 << 29 | 1 << 28)),
+ FloatRegisterSet(FloatRegisters::NoneMask));
+
+ const LiveRegisterSet AllFloatRegisters =
+ LiveRegisterSet(GeneralRegisterSet(Registers::NoneMask),
+ FloatRegisterSet(FloatRegisters::AllMask));
+
+ // Push all general-purpose registers.
+ //
+ // The ARM64 ABI does not treat SP as a normal register that can
+ // be pushed. So pushing happens in two phases.
+ //
+ // Registers are pushed in reverse order of code.
+ //
+ // See block comment in MacroAssembler.h for further required invariants.
+
+ // First, push the last four registers, passing zero for sp.
+ // Zero is pushed for x28 and x31: the pseudo-SP and SP, respectively.
+ masm.asVIXL().Push(xzr, x30, x29, xzr);
+
+ // Second, push the first 28 registers that serve no special purpose.
+ masm.PushRegsInMask(First28GeneralRegisters);
+
+ // Finally, push all floating-point registers, completing the RegisterDump.
+ masm.PushRegsInMask(AllFloatRegisters);
+}
+
+void JitRuntime::generateInvalidator(MacroAssembler& masm, Label* bailoutTail) {
+ AutoCreatedBy acb(masm, "JitRuntime::generateInvalidator");
+
+ invalidatorOffset_ = startTrampolineCode(masm);
+
+ // The InvalidationBailoutStack saved in r0 must be:
+ // - osiPointReturnAddress_
+ // - ionScript_ (pushed by CodeGeneratorARM64::generateInvalidateEpilogue())
+ // - regs_ (pushed here)
+ // - fpregs_ (pushed here) [=r0]
+ PushRegisterDump(masm);
+ masm.moveStackPtrTo(r0);
+
+ // Reserve space for InvalidationBailout's bailoutInfo outparam.
+ masm.Sub(x1, masm.GetStackPointer64(), Operand(sizeof(void*)));
+ masm.moveToStackPtr(r1);
+
+ using Fn =
+ bool (*)(InvalidationBailoutStack * sp, BaselineBailoutInfo * *info);
+ masm.setupUnalignedABICall(r10);
+ masm.passABIArg(r0);
+ masm.passABIArg(r1);
+
+ masm.callWithABI<Fn, InvalidationBailout>(
+ MoveOp::GENERAL, CheckUnsafeCallWithABI::DontCheckOther);
+
+ masm.pop(r2); // Get the bailoutInfo outparam.
+
+ // Pop the machine state and the dead frame.
+ masm.moveToStackPtr(FramePointer);
+
+ // Jump to shared bailout tail. The BailoutInfo pointer has to be in r2.
+ masm.jump(bailoutTail);
+}
+
+void JitRuntime::generateArgumentsRectifier(MacroAssembler& masm,
+ ArgumentsRectifierKind kind) {
+ AutoCreatedBy acb(masm, "JitRuntime::generateArgumentsRectifier");
+
+ switch (kind) {
+ case ArgumentsRectifierKind::Normal:
+ argumentsRectifierOffset_ = startTrampolineCode(masm);
+ break;
+ case ArgumentsRectifierKind::TrialInlining:
+ trialInliningArgumentsRectifierOffset_ = startTrampolineCode(masm);
+ break;
+ }
+
+ // Save the return address for later.
+ masm.push(lr);
+
+ // Frame prologue.
+ //
+ // NOTE: if this changes, fix the Baseline bailout code too!
+ // See BaselineStackBuilder::calculatePrevFramePtr and
+ // BaselineStackBuilder::buildRectifierFrame (in BaselineBailouts.cpp).
+ masm.push(FramePointer);
+ masm.moveStackPtrTo(FramePointer);
+
+ // Load the information that the rectifier needs from the stack.
+ masm.loadNumActualArgs(FramePointer, r0);
+ masm.loadPtr(
+ Address(FramePointer, RectifierFrameLayout::offsetOfCalleeToken()), r1);
+
+ // 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.loadFunctionArgCount(x5.asUnsized(), x6.asUnsized());
+
+ static_assert(CalleeToken_FunctionConstructing == 0x1,
+ "Constructing must be low-order bit");
+ masm.And(x4, x1, Operand(CalleeToken_FunctionConstructing));
+ masm.Add(x7, x6, x4);
+
+ // Copy the number of actual arguments into r8.
+ masm.mov(r0, r8);
+
+ // Calculate the position that our arguments are at before sp gets modified.
+ masm.Add(x3, masm.GetStackPointer64(), Operand(x8, vixl::LSL, 3));
+ masm.Add(x3, x3, Operand(sizeof(RectifierFrameLayout)));
+
+ // If the number of Values without |this| is even, push 8 padding bytes to
+ // ensure the stack is 16-byte aligned.
+ Label noPadding;
+ masm.Tbnz(x7, 0, &noPadding);
+ masm.asVIXL().Push(xzr);
+ 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(), ValueOperand(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);
+ }
+
+ masm.push(r1); // Callee token.
+ masm.pushFrameDescriptorForJitCall(FrameType::Rectifier, r0, r0);
+
+ // Call the target function.
+ switch (kind) {
+ case ArgumentsRectifierKind::Normal:
+ masm.loadJitCodeRaw(r5, r3);
+ argumentsRectifierReturnOffset_ = masm.callJitNoProfiler(r3);
+ break;
+ case ArgumentsRectifierKind::TrialInlining:
+ Label noBaselineScript, done;
+ masm.loadBaselineJitCodeRaw(r5, r3, &noBaselineScript);
+ masm.callJitNoProfiler(r3);
+ masm.jump(&done);
+
+ // See BaselineCacheIRCompiler::emitCallInlinedFunction.
+ masm.bind(&noBaselineScript);
+ masm.loadJitCodeRaw(r5, r3);
+ masm.callJitNoProfiler(r3);
+ masm.bind(&done);
+ break;
+ }
+
+ masm.moveToStackPtr(FramePointer);
+ masm.pop(FramePointer);
+ masm.ret();
+}
+
+static void PushBailoutFrame(MacroAssembler& masm, Register spArg) {
+ // This assumes no SIMD registers, as JS does not support SIMD.
+
+ // The stack saved in spArg must be (higher entries have higher memory
+ // addresses):
+ // - snapshotOffset_
+ // - frameSize_
+ // - regs_
+ // - fpregs_ (spArg + 0)
+ PushRegisterDump(masm);
+ masm.moveStackPtrTo(spArg);
+}
+
+static void GenerateBailoutThunk(MacroAssembler& masm, Label* bailoutTail) {
+ PushBailoutFrame(masm, 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.
+ masm.reserveStack(sizeof(void*));
+ masm.moveStackPtrTo(r1);
+
+ using Fn = bool (*)(BailoutStack * sp, BaselineBailoutInfo * *info);
+ masm.setupUnalignedABICall(r2);
+ masm.passABIArg(r0);
+ masm.passABIArg(r1);
+ masm.callWithABI<Fn, Bailout>(MoveOp::GENERAL,
+ CheckUnsafeCallWithABI::DontCheckOther);
+
+ // Get the bailoutInfo outparam.
+ masm.pop(r2);
+
+ // Remove both the bailout frame and the topmost Ion frame's stack.
+ masm.moveToStackPtr(FramePointer);
+
+ // Jump to shared bailout tail. The BailoutInfo pointer has to be in r2.
+ masm.jump(bailoutTail);
+}
+
+void JitRuntime::generateBailoutHandler(MacroAssembler& masm,
+ Label* bailoutTail) {
+ AutoCreatedBy acb(masm, "JitRuntime::generateBailoutHandler");
+
+ bailoutHandlerOffset_ = startTrampolineCode(masm);
+
+ GenerateBailoutThunk(masm, bailoutTail);
+}
+
+bool JitRuntime::generateVMWrapper(JSContext* cx, MacroAssembler& masm,
+ const VMFunctionData& f, DynFn nativeFun,
+ uint32_t* wrapperOffset) {
+ AutoCreatedBy acb(masm, "JitRuntime::generateVMWrapper");
+
+ *wrapperOffset = startTrampolineCode(masm);
+
+ // Avoid conflicts with argument registers while discarding the result after
+ // the function call.
+ AllocatableGeneralRegisterSet regs(Register::Codes::WrapperMask);
+
+ static_assert(
+ (Register::Codes::VolatileMask & ~Register::Codes::WrapperMask) == 0,
+ "Wrapper register set must be a superset of the Volatile register set.");
+
+ // 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)
+ //
+ // Push the frame pointer to finish the exit frame, then link it up.
+ masm.Push(FramePointer);
+ masm.moveStackPtrTo(FramePointer);
+ masm.loadJSContext(reg_cx);
+ masm.enterExitFrame(reg_cx, regs.getAny(), &f);
+
+ // 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;
+ }
+
+ masm.setupUnalignedABICall(regs.getAny());
+ masm.passABIArg(reg_cx);
+
+ size_t argDisp = 0;
+
+ // Copy arguments.
+ for (uint32_t explicitArg = 0; explicitArg < f.explicitArgs; explicitArg++) {
+ switch (f.argProperties(explicitArg)) {
+ case VMFunctionData::WordByValue:
+ masm.passABIArg(MoveOperand(argsBase, argDisp),
+ (f.argPassedInFloatReg(explicitArg) ? MoveOp::DOUBLE
+ : MoveOp::GENERAL));
+ argDisp += sizeof(void*);
+ break;
+
+ case VMFunctionData::WordByRef:
+ masm.passABIArg(
+ MoveOperand(argsBase, argDisp, MoveOperand::Kind::EffectiveAddress),
+ MoveOp::GENERAL);
+ argDisp += sizeof(void*);
+ break;
+
+ case VMFunctionData::DoubleByValue:
+ case VMFunctionData::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(nativeFun, MoveOp::GENERAL,
+ CheckUnsafeCallWithABI::DontCheckHasExitFrame);
+
+ // SP is used to transfer stack across call boundaries.
+ masm.initPseudoStackPtr();
+
+ // Test for failure.
+ switch (f.failType()) {
+ case Type_Cell:
+ 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_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:
+ 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;
+ }
+
+ // Until C++ code is instrumented against Spectre, prevent speculative
+ // execution from returning any private data.
+ if (f.returnsData() && JitOptions.spectreJitToCxxCalls) {
+ masm.speculationBarrier();
+ }
+
+ // Pop ExitFooterFrame and the frame pointer.
+ masm.leaveExitFrame(0);
+ masm.pop(FramePointer);
+
+ // Return. Subtract sizeof(void*) for the frame pointer.
+ masm.retn(Imm32(sizeof(ExitFrameLayout) - sizeof(void*) +
+ f.explicitStackSlots() * sizeof(void*) +
+ f.extraValuesToPop * sizeof(Value)));
+
+ return true;
+}
+
+uint32_t JitRuntime::generatePreBarrier(JSContext* cx, MacroAssembler& masm,
+ MIRType type) {
+ AutoCreatedBy acb(masm, "JitRuntime::generatePreBarrier");
+
+ uint32_t offset = startTrampolineCode(masm);
+
+ 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 regs =
+ LiveRegisterSet(GeneralRegisterSet(Registers::VolatileMask),
+ FloatRegisterSet(FloatRegisters::VolatileMask));
+
+ // Also preserve the return address.
+ regs.add(lr);
+
+ masm.PushRegsInMask(regs);
+
+ masm.movePtr(ImmPtr(cx->runtime()), r3);
+
+ masm.setupUnalignedABICall(r0);
+ masm.passABIArg(r3);
+ masm.passABIArg(PreBarrierReg);
+ masm.callWithABI(JitPreWriteBarrier(type));
+
+ // Pop the volatile regs and restore LR.
+ masm.PopRegsInMask(regs);
+ masm.abiret();
+
+ masm.bind(&noBarrier);
+ masm.pop(temp3);
+ masm.pop(temp2);
+ masm.pop(temp1);
+ masm.abiret();
+
+ return offset;
+}
+
+void JitRuntime::generateBailoutTailStub(MacroAssembler& masm,
+ Label* bailoutTail) {
+ AutoCreatedBy acb(masm, "JitRuntime::generateBailoutTailStub");
+
+ masm.bind(bailoutTail);
+ masm.generateBailoutTail(r1, r2);
+}