michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
michael@0:  * vim: set ts=8 sts=4 et sw=4 tw=99:
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef jit_mips_BaselineHelpers_mips_h
michael@0: #define jit_mips_BaselineHelpers_mips_h
michael@0: 
michael@0: #ifdef JS_ION
michael@0: #include "jit/BaselineFrame.h"
michael@0: #include "jit/BaselineIC.h"
michael@0: #include "jit/BaselineRegisters.h"
michael@0: #include "jit/IonMacroAssembler.h"
michael@0: 
michael@0: namespace js {
michael@0: namespace jit {
michael@0: 
michael@0: // Distance from sp to the top Value inside an IC stub (no return address on
michael@0: // the stack on MIPS).
michael@0: static const size_t ICStackValueOffset = 0;
michael@0: 
michael@0: inline void
michael@0: EmitRestoreTailCallReg(MacroAssembler &masm)
michael@0: {
michael@0:     // No-op on MIPS because ra register is always holding the return address.
michael@0: }
michael@0: 
michael@0: inline void
michael@0: EmitRepushTailCallReg(MacroAssembler &masm)
michael@0: {
michael@0:     // No-op on MIPS because ra register is always holding the return address.
michael@0: }
michael@0: 
michael@0: inline void
michael@0: EmitCallIC(CodeOffsetLabel *patchOffset, MacroAssembler &masm)
michael@0: {
michael@0:     // Move ICEntry offset into BaselineStubReg.
michael@0:     CodeOffsetLabel offset = masm.movWithPatch(ImmWord(-1), BaselineStubReg);
michael@0:     *patchOffset = offset;
michael@0: 
michael@0:     // Load stub pointer into BaselineStubReg.
michael@0:     masm.loadPtr(Address(BaselineStubReg, ICEntry::offsetOfFirstStub()), BaselineStubReg);
michael@0: 
michael@0:     // Load stubcode pointer from BaselineStubEntry.
michael@0:     // R2 won't be active when we call ICs, so we can use it as scratch.
michael@0:     masm.loadPtr(Address(BaselineStubReg, ICStub::offsetOfStubCode()), R2.scratchReg());
michael@0: 
michael@0:     // Call the stubcode via a direct jump-and-link
michael@0:     masm.call(R2.scratchReg());
michael@0: }
michael@0: 
michael@0: inline void
michael@0: EmitEnterTypeMonitorIC(MacroAssembler &masm,
michael@0:                        size_t monitorStubOffset = ICMonitoredStub::offsetOfFirstMonitorStub())
michael@0: {
michael@0:     // This is expected to be called from within an IC, when BaselineStubReg
michael@0:     // is properly initialized to point to the stub.
michael@0:     masm.loadPtr(Address(BaselineStubReg, (uint32_t) monitorStubOffset), BaselineStubReg);
michael@0: 
michael@0:     // Load stubcode pointer from BaselineStubEntry.
michael@0:     // R2 won't be active when we call ICs, so we can use it.
michael@0:     masm.loadPtr(Address(BaselineStubReg, ICStub::offsetOfStubCode()), R2.scratchReg());
michael@0: 
michael@0:     // Jump to the stubcode.
michael@0:     masm.branch(R2.scratchReg());
michael@0: }
michael@0: 
michael@0: inline void
michael@0: EmitReturnFromIC(MacroAssembler &masm)
michael@0: {
michael@0:     masm.branch(ra);
michael@0: }
michael@0: 
michael@0: inline void
michael@0: EmitChangeICReturnAddress(MacroAssembler &masm, Register reg)
michael@0: {
michael@0:     masm.movePtr(reg, ra);
michael@0: }
michael@0: 
michael@0: inline void
michael@0: EmitTailCallVM(JitCode *target, MacroAssembler &masm, uint32_t argSize)
michael@0: {
michael@0:     // We assume during this that R0 and R1 have been pushed, and that R2 is
michael@0:     // unused.
michael@0:     MOZ_ASSERT(R2 == ValueOperand(t7, t6));
michael@0: 
michael@0:     // Compute frame size.
michael@0:     masm.movePtr(BaselineFrameReg, t6);
michael@0:     masm.addPtr(Imm32(BaselineFrame::FramePointerOffset), t6);
michael@0:     masm.subPtr(BaselineStackReg, t6);
michael@0: 
michael@0:     // Store frame size without VMFunction arguments for GC marking.
michael@0:     masm.ma_subu(t7, t6, Imm32(argSize));
michael@0:     masm.storePtr(t7, Address(BaselineFrameReg, BaselineFrame::reverseOffsetOfFrameSize()));
michael@0: 
michael@0:     // Push frame descriptor and perform the tail call.
michael@0:     // BaselineTailCallReg (ra) already contains the return address (as we
michael@0:     // keep it there through the stub calls), but the VMWrapper code being
michael@0:     // called expects the return address to also be pushed on the stack.
michael@0:     MOZ_ASSERT(BaselineTailCallReg == ra);
michael@0:     masm.makeFrameDescriptor(t6, JitFrame_BaselineJS);
michael@0:     masm.subPtr(Imm32(sizeof(IonCommonFrameLayout)), StackPointer);
michael@0:     masm.storePtr(t6, Address(StackPointer, IonCommonFrameLayout::offsetOfDescriptor()));
michael@0:     masm.storePtr(ra, Address(StackPointer, IonCommonFrameLayout::offsetOfReturnAddress()));
michael@0: 
michael@0:     masm.branch(target);
michael@0: }
michael@0: 
michael@0: inline void
michael@0: EmitCreateStubFrameDescriptor(MacroAssembler &masm, Register reg)
michael@0: {
michael@0:     // Compute stub frame size. We have to add two pointers: the stub reg and
michael@0:     // previous frame pointer pushed by EmitEnterStubFrame.
michael@0:     masm.movePtr(BaselineFrameReg, reg);
michael@0:     masm.addPtr(Imm32(sizeof(intptr_t) * 2), reg);
michael@0:     masm.subPtr(BaselineStackReg, reg);
michael@0: 
michael@0:     masm.makeFrameDescriptor(reg, JitFrame_BaselineStub);
michael@0: }
michael@0: 
michael@0: inline void
michael@0: EmitCallVM(JitCode *target, MacroAssembler &masm)
michael@0: {
michael@0:     EmitCreateStubFrameDescriptor(masm, t6);
michael@0:     masm.push(t6);
michael@0:     masm.call(target);
michael@0: }
michael@0: 
michael@0: struct BaselineStubFrame {
michael@0:     uintptr_t savedFrame;
michael@0:     uintptr_t savedStub;
michael@0:     uintptr_t returnAddress;
michael@0:     uintptr_t descriptor;
michael@0: };
michael@0: 
michael@0: static const uint32_t STUB_FRAME_SIZE = sizeof(BaselineStubFrame);
michael@0: static const uint32_t STUB_FRAME_SAVED_STUB_OFFSET = offsetof(BaselineStubFrame, savedStub);
michael@0: 
michael@0: inline void
michael@0: EmitEnterStubFrame(MacroAssembler &masm, Register scratch)
michael@0: {
michael@0:     MOZ_ASSERT(scratch != BaselineTailCallReg);
michael@0: 
michael@0:     // Compute frame size.
michael@0:     masm.movePtr(BaselineFrameReg, scratch);
michael@0:     masm.addPtr(Imm32(BaselineFrame::FramePointerOffset), scratch);
michael@0:     masm.subPtr(BaselineStackReg, scratch);
michael@0: 
michael@0:     masm.storePtr(scratch, Address(BaselineFrameReg, BaselineFrame::reverseOffsetOfFrameSize()));
michael@0: 
michael@0:     // Note: when making changes here, don't forget to update
michael@0:     // BaselineStubFrame if needed.
michael@0: 
michael@0:     // Push frame descriptor and return address.
michael@0:     masm.makeFrameDescriptor(scratch, JitFrame_BaselineJS);
michael@0:     masm.subPtr(Imm32(STUB_FRAME_SIZE), StackPointer);
michael@0:     masm.storePtr(scratch, Address(StackPointer, offsetof(BaselineStubFrame, descriptor)));
michael@0:     masm.storePtr(BaselineTailCallReg, Address(StackPointer,
michael@0:                                                offsetof(BaselineStubFrame, returnAddress)));
michael@0: 
michael@0:     // Save old frame pointer, stack pointer and stub reg.
michael@0:     masm.storePtr(BaselineStubReg, Address(StackPointer,
michael@0:                                            offsetof(BaselineStubFrame, savedStub)));
michael@0:     masm.storePtr(BaselineFrameReg, Address(StackPointer,
michael@0:                                             offsetof(BaselineStubFrame, savedFrame)));
michael@0:     masm.movePtr(BaselineStackReg, BaselineFrameReg);
michael@0: 
michael@0:     // We pushed 4 words, so the stack is still aligned to 8 bytes.
michael@0:     masm.checkStackAlignment();
michael@0: }
michael@0: 
michael@0: inline void
michael@0: EmitLeaveStubFrame(MacroAssembler &masm, bool calledIntoIon = false)
michael@0: {
michael@0:     // Ion frames do not save and restore the frame pointer. If we called
michael@0:     // into Ion, we have to restore the stack pointer from the frame descriptor.
michael@0:     // If we performed a VM call, the descriptor has been popped already so
michael@0:     // in that case we use the frame pointer.
michael@0:     if (calledIntoIon) {
michael@0:         masm.pop(ScratchRegister);
michael@0:         masm.rshiftPtr(Imm32(FRAMESIZE_SHIFT), ScratchRegister);
michael@0:         masm.addPtr(ScratchRegister, BaselineStackReg);
michael@0:     } else {
michael@0:         masm.movePtr(BaselineFrameReg, BaselineStackReg);
michael@0:     }
michael@0: 
michael@0:     masm.loadPtr(Address(StackPointer, offsetof(BaselineStubFrame, savedFrame)),
michael@0:                  BaselineFrameReg);
michael@0:     masm.loadPtr(Address(StackPointer, offsetof(BaselineStubFrame, savedStub)),
michael@0:                  BaselineStubReg);
michael@0: 
michael@0:     // Load the return address.
michael@0:     masm.loadPtr(Address(StackPointer, offsetof(BaselineStubFrame, returnAddress)),
michael@0:                  BaselineTailCallReg);
michael@0: 
michael@0:     // Discard the frame descriptor.
michael@0:     masm.loadPtr(Address(StackPointer, offsetof(BaselineStubFrame, descriptor)), ScratchRegister);
michael@0:     masm.addPtr(Imm32(STUB_FRAME_SIZE), StackPointer);
michael@0: }
michael@0: 
michael@0: inline void
michael@0: EmitStowICValues(MacroAssembler &masm, int values)
michael@0: {
michael@0:     MOZ_ASSERT(values >= 0 && values <= 2);
michael@0:     switch(values) {
michael@0:       case 1:
michael@0:         // Stow R0
michael@0:         masm.pushValue(R0);
michael@0:         break;
michael@0:       case 2:
michael@0:         // Stow R0 and R1
michael@0:         masm.pushValue(R0);
michael@0:         masm.pushValue(R1);
michael@0:         break;
michael@0:     }
michael@0: }
michael@0: 
michael@0: inline void
michael@0: EmitUnstowICValues(MacroAssembler &masm, int values, bool discard = false)
michael@0: {
michael@0:     MOZ_ASSERT(values >= 0 && values <= 2);
michael@0:     switch(values) {
michael@0:       case 1:
michael@0:         // Unstow R0.
michael@0:         if (discard)
michael@0:             masm.addPtr(Imm32(sizeof(Value)), BaselineStackReg);
michael@0:         else
michael@0:             masm.popValue(R0);
michael@0:         break;
michael@0:       case 2:
michael@0:         // Unstow R0 and R1.
michael@0:         if (discard) {
michael@0:             masm.addPtr(Imm32(sizeof(Value) * 2), BaselineStackReg);
michael@0:         } else {
michael@0:             masm.popValue(R1);
michael@0:             masm.popValue(R0);
michael@0:         }
michael@0:         break;
michael@0:     }
michael@0: }
michael@0: 
michael@0: inline void
michael@0: EmitCallTypeUpdateIC(MacroAssembler &masm, JitCode *code, uint32_t objectOffset)
michael@0: {
michael@0:     // R0 contains the value that needs to be typechecked.
michael@0:     // The object we're updating is a boxed Value on the stack, at offset
michael@0:     // objectOffset from $sp, excluding the return address.
michael@0: 
michael@0:     // Save the current BaselineStubReg to stack, as well as the TailCallReg,
michael@0:     // since on mips, the $ra is live.
michael@0:     masm.subPtr(Imm32(2 * sizeof(intptr_t)), StackPointer);
michael@0:     masm.storePtr(BaselineStubReg, Address(StackPointer, sizeof(intptr_t)));
michael@0:     masm.storePtr(BaselineTailCallReg, Address(StackPointer, 0));
michael@0: 
michael@0:     // This is expected to be called from within an IC, when BaselineStubReg
michael@0:     // is properly initialized to point to the stub.
michael@0:     masm.loadPtr(Address(BaselineStubReg, ICUpdatedStub::offsetOfFirstUpdateStub()),
michael@0:                  BaselineStubReg);
michael@0: 
michael@0:     // Load stubcode pointer from BaselineStubReg into BaselineTailCallReg.
michael@0:     masm.loadPtr(Address(BaselineStubReg, ICStub::offsetOfStubCode()), R2.scratchReg());
michael@0: 
michael@0:     // Call the stubcode.
michael@0:     masm.call(R2.scratchReg());
michael@0: 
michael@0:     // Restore the old stub reg and tailcall reg.
michael@0:     masm.loadPtr(Address(StackPointer, 0), BaselineTailCallReg);
michael@0:     masm.loadPtr(Address(StackPointer, sizeof(intptr_t)), BaselineStubReg);
michael@0:     masm.addPtr(Imm32(2 * sizeof(intptr_t)), StackPointer);
michael@0: 
michael@0:     // The update IC will store 0 or 1 in R1.scratchReg() reflecting if the
michael@0:     // value in R0 type-checked properly or not.
michael@0:     Label success;
michael@0:     masm.ma_b(R1.scratchReg(), Imm32(1), &success, Assembler::Equal, ShortJump);
michael@0: 
michael@0:     // If the IC failed, then call the update fallback function.
michael@0:     EmitEnterStubFrame(masm, R1.scratchReg());
michael@0: 
michael@0:     masm.loadValue(Address(BaselineStackReg, STUB_FRAME_SIZE + objectOffset), R1);
michael@0: 
michael@0:     masm.pushValue(R0);
michael@0:     masm.pushValue(R1);
michael@0:     masm.push(BaselineStubReg);
michael@0: 
michael@0:     // Load previous frame pointer, push BaselineFrame *.
michael@0:     masm.loadPtr(Address(BaselineFrameReg, 0), R0.scratchReg());
michael@0:     masm.pushBaselineFramePtr(R0.scratchReg(), R0.scratchReg());
michael@0: 
michael@0:     EmitCallVM(code, masm);
michael@0:     EmitLeaveStubFrame(masm);
michael@0: 
michael@0:     // Success at end.
michael@0:     masm.bind(&success);
michael@0: }
michael@0: 
michael@0: template <typename AddrType>
michael@0: inline void
michael@0: EmitPreBarrier(MacroAssembler &masm, const AddrType &addr, MIRType type)
michael@0: {
michael@0:     // On MIPS, $ra is clobbered by patchableCallPreBarrier. Save it first.
michael@0:     masm.push(ra);
michael@0:     masm.patchableCallPreBarrier(addr, type);
michael@0:     masm.pop(ra);
michael@0: }
michael@0: 
michael@0: inline void
michael@0: EmitStubGuardFailure(MacroAssembler &masm)
michael@0: {
michael@0:     // NOTE: This routine assumes that the stub guard code left the stack in
michael@0:     // the same state it was in when it was entered.
michael@0: 
michael@0:     // BaselineStubEntry points to the current stub.
michael@0: 
michael@0:     // Load next stub into BaselineStubReg
michael@0:     masm.loadPtr(Address(BaselineStubReg, ICStub::offsetOfNext()), BaselineStubReg);
michael@0: 
michael@0:     // Load stubcode pointer from BaselineStubEntry into scratch register.
michael@0:     masm.loadPtr(Address(BaselineStubReg, ICStub::offsetOfStubCode()), R2.scratchReg());
michael@0: 
michael@0:     // Return address is already loaded, just jump to the next stubcode.
michael@0:     MOZ_ASSERT(BaselineTailCallReg == ra);
michael@0:     masm.branch(R2.scratchReg());
michael@0: }
michael@0: 
michael@0: 
michael@0: } // namespace jit
michael@0: } // namespace js
michael@0: 
michael@0: #endif // JS_ION
michael@0: 
michael@0: #endif /* jit_mips_BaselineHelpers_mips_h */
michael@0: