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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/. */
#ifndef jit_mips_BaselineHelpers_mips_h
#define jit_mips_BaselineHelpers_mips_h
#ifdef JS_ION
#include "jit/BaselineFrame.h"
#include "jit/BaselineIC.h"
#include "jit/BaselineRegisters.h"
#include "jit/IonMacroAssembler.h"
namespace js {
namespace jit {
// Distance from sp to the top Value inside an IC stub (no return address on
// the stack on MIPS).
static const size_t ICStackValueOffset = 0;
inline void
EmitRestoreTailCallReg(MacroAssembler &masm)
{
// No-op on MIPS because ra register is always holding the return address.
}
inline void
EmitRepushTailCallReg(MacroAssembler &masm)
{
// No-op on MIPS because ra register is always holding the return address.
}
inline void
EmitCallIC(CodeOffsetLabel *patchOffset, MacroAssembler &masm)
{
// Move ICEntry offset into BaselineStubReg.
CodeOffsetLabel offset = masm.movWithPatch(ImmWord(-1), BaselineStubReg);
*patchOffset = offset;
// Load stub pointer into BaselineStubReg.
masm.loadPtr(Address(BaselineStubReg, ICEntry::offsetOfFirstStub()), BaselineStubReg);
// Load stubcode pointer from BaselineStubEntry.
// R2 won't be active when we call ICs, so we can use it as scratch.
masm.loadPtr(Address(BaselineStubReg, ICStub::offsetOfStubCode()), R2.scratchReg());
// Call the stubcode via a direct jump-and-link
masm.call(R2.scratchReg());
}
inline void
EmitEnterTypeMonitorIC(MacroAssembler &masm,
size_t monitorStubOffset = ICMonitoredStub::offsetOfFirstMonitorStub())
{
// This is expected to be called from within an IC, when BaselineStubReg
// is properly initialized to point to the stub.
masm.loadPtr(Address(BaselineStubReg, (uint32_t) monitorStubOffset), BaselineStubReg);
// Load stubcode pointer from BaselineStubEntry.
// R2 won't be active when we call ICs, so we can use it.
masm.loadPtr(Address(BaselineStubReg, ICStub::offsetOfStubCode()), R2.scratchReg());
// Jump to the stubcode.
masm.branch(R2.scratchReg());
}
inline void
EmitReturnFromIC(MacroAssembler &masm)
{
masm.branch(ra);
}
inline void
EmitChangeICReturnAddress(MacroAssembler &masm, Register reg)
{
masm.movePtr(reg, ra);
}
inline void
EmitTailCallVM(IonCode *target, MacroAssembler &masm, uint32_t argSize)
{
// We assume during this that R0 and R1 have been pushed, and that R2 is
// unused.
MOZ_ASSERT(R2 == ValueOperand(t7, t6));
// Compute frame size.
masm.movePtr(BaselineFrameReg, t6);
masm.addPtr(Imm32(BaselineFrame::FramePointerOffset), t6);
masm.subPtr(BaselineStackReg, t6);
// Store frame size without VMFunction arguments for GC marking.
masm.ma_subu(t7, t6, Imm32(argSize));
masm.storePtr(t7, Address(BaselineFrameReg, BaselineFrame::reverseOffsetOfFrameSize()));
// Push frame descriptor and perform the tail call.
// BaselineTailCallReg (ra) already contains the return address (as we
// keep it there through the stub calls), but the VMWrapper code being
// called expects the return address to also be pushed on the stack.
MOZ_ASSERT(BaselineTailCallReg == ra);
masm.makeFrameDescriptor(t6, IonFrame_BaselineJS);
masm.subPtr(Imm32(sizeof(IonCommonFrameLayout)), StackPointer);
masm.storePtr(t6, Address(StackPointer, IonCommonFrameLayout::offsetOfDescriptor()));
masm.storePtr(ra, Address(StackPointer, IonCommonFrameLayout::offsetOfReturnAddress()));
masm.branch(target);
}
inline void
EmitCreateStubFrameDescriptor(MacroAssembler &masm, Register reg)
{
// Compute stub frame size. We have to add two pointers: the stub reg and
// previous frame pointer pushed by EmitEnterStubFrame.
masm.movePtr(BaselineFrameReg, reg);
masm.addPtr(Imm32(sizeof(intptr_t) * 2), reg);
masm.subPtr(BaselineStackReg, reg);
masm.makeFrameDescriptor(reg, IonFrame_BaselineStub);
}
inline void
EmitCallVM(IonCode *target, MacroAssembler &masm)
{
EmitCreateStubFrameDescriptor(masm, t6);
masm.push(t6);
masm.call(target);
}
struct BaselineStubFrame {
uintptr_t savedFrame;
uintptr_t savedStub;
uintptr_t returnAddress;
uintptr_t descriptor;
};
static const uint32_t STUB_FRAME_SIZE = sizeof(BaselineStubFrame);
static const uint32_t STUB_FRAME_SAVED_STUB_OFFSET = offsetof(BaselineStubFrame, savedStub);
inline void
EmitEnterStubFrame(MacroAssembler &masm, Register scratch)
{
MOZ_ASSERT(scratch != BaselineTailCallReg);
// Compute frame size.
masm.movePtr(BaselineFrameReg, scratch);
masm.addPtr(Imm32(BaselineFrame::FramePointerOffset), scratch);
masm.subPtr(BaselineStackReg, scratch);
masm.storePtr(scratch, Address(BaselineFrameReg, BaselineFrame::reverseOffsetOfFrameSize()));
// Note: when making changes here, don't forget to update
// BaselineStubFrame if needed.
// Push frame descriptor and return address.
masm.makeFrameDescriptor(scratch, IonFrame_BaselineJS);
masm.subPtr(Imm32(STUB_FRAME_SIZE), StackPointer);
masm.storePtr(scratch, Address(StackPointer, offsetof(BaselineStubFrame, descriptor)));
masm.storePtr(BaselineTailCallReg, Address(StackPointer,
offsetof(BaselineStubFrame, returnAddress)));
// Save old frame pointer, stack pointer and stub reg.
masm.storePtr(BaselineStubReg, Address(StackPointer,
offsetof(BaselineStubFrame, savedStub)));
masm.storePtr(BaselineFrameReg, Address(StackPointer,
offsetof(BaselineStubFrame, savedFrame)));
masm.movePtr(BaselineStackReg, BaselineFrameReg);
// We pushed 4 words, so the stack is still aligned to 8 bytes.
masm.checkStackAlignment();
}
inline void
EmitLeaveStubFrame(MacroAssembler &masm, bool calledIntoIon = false)
{
// Ion frames do not save and restore the frame pointer. If we called
// into Ion, we have to restore the stack pointer from the frame descriptor.
// If we performed a VM call, the descriptor has been popped already so
// in that case we use the frame pointer.
if (calledIntoIon) {
masm.pop(ScratchRegister);
masm.rshiftPtr(Imm32(FRAMESIZE_SHIFT), ScratchRegister);
masm.addPtr(ScratchRegister, BaselineStackReg);
} else {
masm.movePtr(BaselineFrameReg, BaselineStackReg);
}
masm.loadPtr(Address(StackPointer, offsetof(BaselineStubFrame, savedFrame)),
BaselineFrameReg);
masm.loadPtr(Address(StackPointer, offsetof(BaselineStubFrame, savedStub)),
BaselineStubReg);
// Load the return address.
masm.loadPtr(Address(StackPointer, offsetof(BaselineStubFrame, returnAddress)),
BaselineTailCallReg);
// Discard the frame descriptor.
masm.loadPtr(Address(StackPointer, offsetof(BaselineStubFrame, descriptor)), ScratchRegister);
masm.addPtr(Imm32(STUB_FRAME_SIZE), StackPointer);
}
inline void
EmitStowICValues(MacroAssembler &masm, int values)
{
MOZ_ASSERT(values >= 0 && values <= 2);
switch(values) {
case 1:
// Stow R0
masm.pushValue(R0);
break;
case 2:
// Stow R0 and R1
masm.pushValue(R0);
masm.pushValue(R1);
break;
}
}
inline void
EmitUnstowICValues(MacroAssembler &masm, int values, bool discard = false)
{
MOZ_ASSERT(values >= 0 && values <= 2);
switch(values) {
case 1:
// Unstow R0.
if (discard)
masm.addPtr(Imm32(sizeof(Value)), BaselineStackReg);
else
masm.popValue(R0);
break;
case 2:
// Unstow R0 and R1.
if (discard) {
masm.addPtr(Imm32(sizeof(Value) * 2), BaselineStackReg);
} else {
masm.popValue(R1);
masm.popValue(R0);
}
break;
}
}
inline void
EmitCallTypeUpdateIC(MacroAssembler &masm, IonCode *code, uint32_t objectOffset)
{
// R0 contains the value that needs to be typechecked.
// The object we're updating is a boxed Value on the stack, at offset
// objectOffset from $sp, excluding the return address.
// Save the current BaselineStubReg to stack, as well as the TailCallReg,
// since on mips, the $ra is live.
masm.subPtr(Imm32(2 * sizeof(intptr_t)), StackPointer);
masm.storePtr(BaselineStubReg, Address(StackPointer, sizeof(intptr_t)));
masm.storePtr(BaselineTailCallReg, Address(StackPointer, 0));
// This is expected to be called from within an IC, when BaselineStubReg
// is properly initialized to point to the stub.
masm.loadPtr(Address(BaselineStubReg, ICUpdatedStub::offsetOfFirstUpdateStub()),
BaselineStubReg);
// Load stubcode pointer from BaselineStubReg into BaselineTailCallReg.
masm.loadPtr(Address(BaselineStubReg, ICStub::offsetOfStubCode()), R2.scratchReg());
// Call the stubcode.
masm.call(R2.scratchReg());
// Restore the old stub reg and tailcall reg.
masm.loadPtr(Address(StackPointer, 0), BaselineTailCallReg);
masm.loadPtr(Address(StackPointer, sizeof(intptr_t)), BaselineStubReg);
masm.addPtr(Imm32(2 * sizeof(intptr_t)), StackPointer);
// The update IC will store 0 or 1 in R1.scratchReg() reflecting if the
// value in R0 type-checked properly or not.
Label success;
masm.ma_b(R1.scratchReg(), Imm32(1), &success, Assembler::Equal, ShortJump);
// If the IC failed, then call the update fallback function.
EmitEnterStubFrame(masm, R1.scratchReg());
masm.loadValue(Address(BaselineStackReg, STUB_FRAME_SIZE + objectOffset), R1);
masm.pushValue(R0);
masm.pushValue(R1);
masm.push(BaselineStubReg);
// Load previous frame pointer, push BaselineFrame *.
masm.loadPtr(Address(BaselineFrameReg, 0), R0.scratchReg());
masm.pushBaselineFramePtr(R0.scratchReg(), R0.scratchReg());
EmitCallVM(code, masm);
EmitLeaveStubFrame(masm);
// Success at end.
masm.bind(&success);
}
template <typename AddrType>
inline void
EmitPreBarrier(MacroAssembler &masm, const AddrType &addr, MIRType type)
{
// On MIPS, $ra is clobbered by patchableCallPreBarrier. Save it first.
masm.push(ra);
masm.patchableCallPreBarrier(addr, type);
masm.pop(ra);
}
inline void
EmitStubGuardFailure(MacroAssembler &masm)
{
// NOTE: This routine assumes that the stub guard code left the stack in
// the same state it was in when it was entered.
// BaselineStubEntry points to the current stub.
// Load next stub into BaselineStubReg
masm.loadPtr(Address(BaselineStubReg, ICStub::offsetOfNext()), BaselineStubReg);
// Load stubcode pointer from BaselineStubEntry into scratch register.
masm.loadPtr(Address(BaselineStubReg, ICStub::offsetOfStubCode()), R2.scratchReg());
// Return address is already loaded, just jump to the next stubcode.
MOZ_ASSERT(BaselineTailCallReg == ra);
masm.branch(R2.scratchReg());
}
} // namespace jit
} // namespace js
#endif // JS_ION
#endif /* jit_mips_BaselineHelpers_mips_h */