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Diffstat (limited to 'js/src/jit/arm/MoveEmitter-arm.cpp')
| -rw-r--r-- | js/src/jit/arm/MoveEmitter-arm.cpp | 413 |
1 files changed, 413 insertions, 0 deletions
diff --git a/js/src/jit/arm/MoveEmitter-arm.cpp b/js/src/jit/arm/MoveEmitter-arm.cpp new file mode 100644 index 0000000000..1807c41b50 --- /dev/null +++ b/js/src/jit/arm/MoveEmitter-arm.cpp @@ -0,0 +1,413 @@ +/* -*- 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/MoveEmitter-arm.h" + +#include "jit/MacroAssembler-inl.h" + +using namespace js; +using namespace js::jit; + +MoveEmitterARM::MoveEmitterARM(MacroAssembler& masm) + : inCycle_(0), + masm(masm), + pushedAtCycle_(-1), + pushedAtSpill_(-1), + spilledReg_(InvalidReg), + spilledFloatReg_(InvalidFloatReg) { + pushedAtStart_ = masm.framePushed(); +} + +void MoveEmitterARM::emit(const MoveResolver& moves) { + if (moves.numCycles()) { + // Reserve stack for cycle resolution + static_assert(SpillSlotSize == 8); + masm.reserveStack(moves.numCycles() * SpillSlotSize); + pushedAtCycle_ = masm.framePushed(); + } + + for (size_t i = 0; i < moves.numMoves(); i++) { + emit(moves.getMove(i)); + } +} + +MoveEmitterARM::~MoveEmitterARM() { assertDone(); } + +Address MoveEmitterARM::cycleSlot(uint32_t slot, uint32_t subslot) const { + int32_t offset = masm.framePushed() - pushedAtCycle_; + MOZ_ASSERT(offset < 4096 && offset > -4096); + return Address(StackPointer, offset + slot * sizeof(double) + subslot); +} + +Address MoveEmitterARM::spillSlot() const { + int32_t offset = masm.framePushed() - pushedAtSpill_; + MOZ_ASSERT(offset < 4096 && offset > -4096); + return Address(StackPointer, offset); +} + +Address MoveEmitterARM::toAddress(const MoveOperand& operand) const { + MOZ_ASSERT(operand.isMemoryOrEffectiveAddress()); + + if (operand.base() != StackPointer) { + return Address(operand.base(), operand.disp()); + } + + MOZ_ASSERT(operand.disp() >= 0); + + // Otherwise, the stack offset may need to be adjusted. + return Address(StackPointer, + operand.disp() + (masm.framePushed() - pushedAtStart_)); +} + +Register MoveEmitterARM::tempReg() { + if (spilledReg_ != InvalidReg) { + return spilledReg_; + } + + // For now, just pick r12/ip as the eviction point. This is totally random, + // and if it ends up being bad, we can use actual heuristics later. r12 is + // actually a bad choice. It is the scratch register, which is frequently + // used for address computations, such as those found when we attempt to + // access values more than 4096 off of the stack pointer. Instead, use lr, + // the LinkRegister. + spilledReg_ = r14; + if (pushedAtSpill_ == -1) { + masm.Push(spilledReg_); + pushedAtSpill_ = masm.framePushed(); + } else { + ScratchRegisterScope scratch(masm); + masm.ma_str(spilledReg_, spillSlot(), scratch); + } + return spilledReg_; +} + +void MoveEmitterARM::breakCycle(const MoveOperand& from, const MoveOperand& to, + MoveOp::Type type, uint32_t slotId) { + // There is some pattern: + // (A -> B) + // (B -> A) + // + // This case handles (A -> B), which we reach first. We save B, then allow + // the original move to continue. + + ScratchRegisterScope scratch(masm); + + switch (type) { + case MoveOp::FLOAT32: + if (to.isMemory()) { + ScratchFloat32Scope scratchFloat32(masm); + masm.ma_vldr(toAddress(to), scratchFloat32, scratch); + // Since it is uncertain if the load will be aligned or not + // just fill both of them with the same value. + masm.ma_vstr(scratchFloat32, cycleSlot(slotId, 0), scratch); + masm.ma_vstr(scratchFloat32, cycleSlot(slotId, 4), scratch); + } else if (to.isGeneralReg()) { + // Since it is uncertain if the load will be aligned or not + // just fill both of them with the same value. + masm.ma_str(to.reg(), cycleSlot(slotId, 0), scratch); + masm.ma_str(to.reg(), cycleSlot(slotId, 4), scratch); + } else { + FloatRegister src = to.floatReg(); + // Just always store the largest possible size. Currently, this is + // a double. When SIMD is added, two doubles will need to be stored. + masm.ma_vstr(src.doubleOverlay(), cycleSlot(slotId, 0), scratch); + } + break; + case MoveOp::DOUBLE: + if (to.isMemory()) { + ScratchDoubleScope scratchDouble(masm); + masm.ma_vldr(toAddress(to), scratchDouble, scratch); + masm.ma_vstr(scratchDouble, cycleSlot(slotId, 0), scratch); + } else if (to.isGeneralRegPair()) { + ScratchDoubleScope scratchDouble(masm); + masm.ma_vxfer(to.evenReg(), to.oddReg(), scratchDouble); + masm.ma_vstr(scratchDouble, cycleSlot(slotId, 0), scratch); + } else { + masm.ma_vstr(to.floatReg().doubleOverlay(), cycleSlot(slotId, 0), + scratch); + } + break; + case MoveOp::INT32: + case MoveOp::GENERAL: + // an non-vfp value + if (to.isMemory()) { + Register temp = tempReg(); + masm.ma_ldr(toAddress(to), temp, scratch); + masm.ma_str(temp, cycleSlot(0, 0), scratch); + } else { + if (to.reg() == spilledReg_) { + // If the destination was spilled, restore it first. + masm.ma_ldr(spillSlot(), spilledReg_, scratch); + spilledReg_ = InvalidReg; + } + masm.ma_str(to.reg(), cycleSlot(0, 0), scratch); + } + break; + default: + MOZ_CRASH("Unexpected move type"); + } +} + +void MoveEmitterARM::completeCycle(const MoveOperand& from, + const MoveOperand& to, MoveOp::Type type, + uint32_t slotId) { + // There is some pattern: + // (A -> B) + // (B -> A) + // + // This case handles (B -> A), which we reach last. We emit a move from the + // saved value of B, to A. + + ScratchRegisterScope scratch(masm); + + switch (type) { + case MoveOp::FLOAT32: + MOZ_ASSERT(!to.isGeneralRegPair()); + if (to.isMemory()) { + ScratchFloat32Scope scratchFloat32(masm); + masm.ma_vldr(cycleSlot(slotId, 0), scratchFloat32, scratch); + masm.ma_vstr(scratchFloat32, toAddress(to), scratch); + } else if (to.isGeneralReg()) { + MOZ_ASSERT(type == MoveOp::FLOAT32); + masm.ma_ldr(toAddress(from), to.reg(), scratch); + } else { + uint32_t offset = 0; + if ((!from.isMemory()) && from.floatReg().numAlignedAliased() == 1) { + offset = sizeof(float); + } + masm.ma_vldr(cycleSlot(slotId, offset), to.floatReg(), scratch); + } + break; + case MoveOp::DOUBLE: + MOZ_ASSERT(!to.isGeneralReg()); + if (to.isMemory()) { + ScratchDoubleScope scratchDouble(masm); + masm.ma_vldr(cycleSlot(slotId, 0), scratchDouble, scratch); + masm.ma_vstr(scratchDouble, toAddress(to), scratch); + } else if (to.isGeneralRegPair()) { + MOZ_ASSERT(type == MoveOp::DOUBLE); + ScratchDoubleScope scratchDouble(masm); + masm.ma_vldr(toAddress(from), scratchDouble, scratch); + masm.ma_vxfer(scratchDouble, to.evenReg(), to.oddReg()); + } else { + uint32_t offset = 0; + if ((!from.isMemory()) && from.floatReg().numAlignedAliased() == 1) { + offset = sizeof(float); + } + masm.ma_vldr(cycleSlot(slotId, offset), to.floatReg(), scratch); + } + break; + case MoveOp::INT32: + case MoveOp::GENERAL: + MOZ_ASSERT(slotId == 0); + if (to.isMemory()) { + Register temp = tempReg(); + masm.ma_ldr(cycleSlot(slotId, 0), temp, scratch); + masm.ma_str(temp, toAddress(to), scratch); + } else { + if (to.reg() == spilledReg_) { + // Make sure we don't re-clobber the spilled register later. + spilledReg_ = InvalidReg; + } + masm.ma_ldr(cycleSlot(slotId, 0), to.reg(), scratch); + } + break; + default: + MOZ_CRASH("Unexpected move type"); + } +} + +void MoveEmitterARM::emitMove(const MoveOperand& from, const MoveOperand& to) { + // Register pairs are used to store Double values during calls. + MOZ_ASSERT(!from.isGeneralRegPair()); + MOZ_ASSERT(!to.isGeneralRegPair()); + + ScratchRegisterScope scratch(masm); + + if (to.isGeneralReg() && to.reg() == spilledReg_) { + // If the destination is the spilled register, make sure we + // don't re-clobber its value. + spilledReg_ = InvalidReg; + } + + if (from.isGeneralReg()) { + if (from.reg() == spilledReg_) { + // If the source is a register that has been spilled, make sure + // to load the source back into that register. + masm.ma_ldr(spillSlot(), spilledReg_, scratch); + spilledReg_ = InvalidReg; + } + if (to.isMemoryOrEffectiveAddress()) { + masm.ma_str(from.reg(), toAddress(to), scratch); + } else { + masm.ma_mov(from.reg(), to.reg()); + } + } else if (to.isGeneralReg()) { + MOZ_ASSERT(from.isMemoryOrEffectiveAddress()); + if (from.isMemory()) { + masm.ma_ldr(toAddress(from), to.reg(), scratch); + } else { + masm.ma_add(from.base(), Imm32(from.disp()), to.reg(), scratch); + } + } else { + // Memory to memory gpr move. + Register reg = tempReg(); + + MOZ_ASSERT(from.isMemoryOrEffectiveAddress()); + if (from.isMemory()) { + masm.ma_ldr(toAddress(from), reg, scratch); + } else { + masm.ma_add(from.base(), Imm32(from.disp()), reg, scratch); + } + MOZ_ASSERT(to.base() != reg); + masm.ma_str(reg, toAddress(to), scratch); + } +} + +void MoveEmitterARM::emitFloat32Move(const MoveOperand& from, + const MoveOperand& to) { + // Register pairs are used to store Double values during calls. + MOZ_ASSERT(!from.isGeneralRegPair()); + MOZ_ASSERT(!to.isGeneralRegPair()); + + ScratchRegisterScope scratch(masm); + + if (from.isFloatReg()) { + if (to.isFloatReg()) { + masm.ma_vmov_f32(from.floatReg(), to.floatReg()); + } else if (to.isGeneralReg()) { + masm.ma_vxfer(from.floatReg(), to.reg()); + } else { + masm.ma_vstr(VFPRegister(from.floatReg()).singleOverlay(), toAddress(to), + scratch); + } + } else if (from.isGeneralReg()) { + if (to.isFloatReg()) { + masm.ma_vxfer(from.reg(), to.floatReg()); + } else if (to.isGeneralReg()) { + masm.ma_mov(from.reg(), to.reg()); + } else { + masm.ma_str(from.reg(), toAddress(to), scratch); + } + } else if (to.isFloatReg()) { + masm.ma_vldr(toAddress(from), VFPRegister(to.floatReg()).singleOverlay(), + scratch); + } else if (to.isGeneralReg()) { + masm.ma_ldr(toAddress(from), to.reg(), scratch); + } else { + // Memory to memory move. + MOZ_ASSERT(from.isMemory()); + ScratchFloat32Scope scratchFloat32(masm); + masm.ma_vldr(toAddress(from), scratchFloat32, scratch); + masm.ma_vstr(scratchFloat32, toAddress(to), scratch); + } +} + +void MoveEmitterARM::emitDoubleMove(const MoveOperand& from, + const MoveOperand& to) { + // Registers are used to store pointers / int32 / float32 values. + MOZ_ASSERT(!from.isGeneralReg()); + MOZ_ASSERT(!to.isGeneralReg()); + + ScratchRegisterScope scratch(masm); + + if (from.isFloatReg()) { + if (to.isFloatReg()) { + masm.ma_vmov(from.floatReg(), to.floatReg()); + } else if (to.isGeneralRegPair()) { + masm.ma_vxfer(from.floatReg(), to.evenReg(), to.oddReg()); + } else { + masm.ma_vstr(from.floatReg(), toAddress(to), scratch); + } + } else if (from.isGeneralRegPair()) { + if (to.isFloatReg()) { + masm.ma_vxfer(from.evenReg(), from.oddReg(), to.floatReg()); + } else if (to.isGeneralRegPair()) { + MOZ_ASSERT(!from.aliases(to)); + masm.ma_mov(from.evenReg(), to.evenReg()); + masm.ma_mov(from.oddReg(), to.oddReg()); + } else { + ScratchDoubleScope scratchDouble(masm); + masm.ma_vxfer(from.evenReg(), from.oddReg(), scratchDouble); + masm.ma_vstr(scratchDouble, toAddress(to), scratch); + } + } else if (to.isFloatReg()) { + masm.ma_vldr(toAddress(from), to.floatReg(), scratch); + } else if (to.isGeneralRegPair()) { + MOZ_ASSERT(from.isMemory()); + Address src = toAddress(from); + // Note: We can safely use the MoveOperand's displacement here, + // even if the base is SP: MoveEmitter::toOperand adjusts + // SP-relative operands by the difference between the current + // stack usage and stackAdjust, which emitter.finish() resets to + // 0. + // + // Warning: if the offset isn't within [-255,+255] then this + // will assert-fail (or, if non-debug, load the wrong words). + // Nothing uses such an offset at the time of this writing. + masm.ma_ldrd(EDtrAddr(src.base, EDtrOffImm(src.offset)), to.evenReg(), + to.oddReg()); + } else { + // Memory to memory move. + MOZ_ASSERT(from.isMemory()); + ScratchDoubleScope scratchDouble(masm); + masm.ma_vldr(toAddress(from), scratchDouble, scratch); + masm.ma_vstr(scratchDouble, toAddress(to), scratch); + } +} + +void MoveEmitterARM::emit(const MoveOp& move) { + const MoveOperand& from = move.from(); + const MoveOperand& to = move.to(); + + if (move.isCycleEnd() && move.isCycleBegin()) { + // A fun consequence of aliased registers is you can have multiple + // cycles at once, and one can end exactly where another begins. + breakCycle(from, to, move.endCycleType(), move.cycleBeginSlot()); + completeCycle(from, to, move.type(), move.cycleEndSlot()); + return; + } + + if (move.isCycleEnd()) { + MOZ_ASSERT(inCycle_); + completeCycle(from, to, move.type(), move.cycleEndSlot()); + MOZ_ASSERT(inCycle_ > 0); + inCycle_--; + return; + } + + if (move.isCycleBegin()) { + breakCycle(from, to, move.endCycleType(), move.cycleBeginSlot()); + inCycle_++; + } + + switch (move.type()) { + case MoveOp::FLOAT32: + emitFloat32Move(from, to); + break; + case MoveOp::DOUBLE: + emitDoubleMove(from, to); + break; + case MoveOp::INT32: + case MoveOp::GENERAL: + emitMove(from, to); + break; + default: + MOZ_CRASH("Unexpected move type"); + } +} + +void MoveEmitterARM::assertDone() { MOZ_ASSERT(inCycle_ == 0); } + +void MoveEmitterARM::finish() { + assertDone(); + + if (pushedAtSpill_ != -1 && spilledReg_ != InvalidReg) { + ScratchRegisterScope scratch(masm); + masm.ma_ldr(spillSlot(), spilledReg_, scratch); + } + masm.freeStack(masm.framePushed() - pushedAtStart_); +} |