| // Copyright 2011 the V8 project authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "src/v8.h" |
| |
| #if V8_TARGET_ARCH_X64 |
| |
| #include "src/x64/lithium-codegen-x64.h" |
| #include "src/x64/lithium-gap-resolver-x64.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| LGapResolver::LGapResolver(LCodeGen* owner) |
| : cgen_(owner), moves_(32, owner->zone()) {} |
| |
| |
| void LGapResolver::Resolve(LParallelMove* parallel_move) { |
| DCHECK(moves_.is_empty()); |
| // Build up a worklist of moves. |
| BuildInitialMoveList(parallel_move); |
| |
| for (int i = 0; i < moves_.length(); ++i) { |
| LMoveOperands move = moves_[i]; |
| // Skip constants to perform them last. They don't block other moves |
| // and skipping such moves with register destinations keeps those |
| // registers free for the whole algorithm. |
| if (!move.IsEliminated() && !move.source()->IsConstantOperand()) { |
| PerformMove(i); |
| } |
| } |
| |
| // Perform the moves with constant sources. |
| for (int i = 0; i < moves_.length(); ++i) { |
| if (!moves_[i].IsEliminated()) { |
| DCHECK(moves_[i].source()->IsConstantOperand()); |
| EmitMove(i); |
| } |
| } |
| |
| moves_.Rewind(0); |
| } |
| |
| |
| void LGapResolver::BuildInitialMoveList(LParallelMove* parallel_move) { |
| // Perform a linear sweep of the moves to add them to the initial list of |
| // moves to perform, ignoring any move that is redundant (the source is |
| // the same as the destination, the destination is ignored and |
| // unallocated, or the move was already eliminated). |
| const ZoneList<LMoveOperands>* moves = parallel_move->move_operands(); |
| for (int i = 0; i < moves->length(); ++i) { |
| LMoveOperands move = moves->at(i); |
| if (!move.IsRedundant()) moves_.Add(move, cgen_->zone()); |
| } |
| Verify(); |
| } |
| |
| |
| void LGapResolver::PerformMove(int index) { |
| // Each call to this function performs a move and deletes it from the move |
| // graph. We first recursively perform any move blocking this one. We |
| // mark a move as "pending" on entry to PerformMove in order to detect |
| // cycles in the move graph. We use operand swaps to resolve cycles, |
| // which means that a call to PerformMove could change any source operand |
| // in the move graph. |
| |
| DCHECK(!moves_[index].IsPending()); |
| DCHECK(!moves_[index].IsRedundant()); |
| |
| // Clear this move's destination to indicate a pending move. The actual |
| // destination is saved in a stack-allocated local. Recursion may allow |
| // multiple moves to be pending. |
| DCHECK(moves_[index].source() != NULL); // Or else it will look eliminated. |
| LOperand* destination = moves_[index].destination(); |
| moves_[index].set_destination(NULL); |
| |
| // Perform a depth-first traversal of the move graph to resolve |
| // dependencies. Any unperformed, unpending move with a source the same |
| // as this one's destination blocks this one so recursively perform all |
| // such moves. |
| for (int i = 0; i < moves_.length(); ++i) { |
| LMoveOperands other_move = moves_[i]; |
| if (other_move.Blocks(destination) && !other_move.IsPending()) { |
| // Though PerformMove can change any source operand in the move graph, |
| // this call cannot create a blocking move via a swap (this loop does |
| // not miss any). Assume there is a non-blocking move with source A |
| // and this move is blocked on source B and there is a swap of A and |
| // B. Then A and B must be involved in the same cycle (or they would |
| // not be swapped). Since this move's destination is B and there is |
| // only a single incoming edge to an operand, this move must also be |
| // involved in the same cycle. In that case, the blocking move will |
| // be created but will be "pending" when we return from PerformMove. |
| PerformMove(i); |
| } |
| } |
| |
| // We are about to resolve this move and don't need it marked as |
| // pending, so restore its destination. |
| moves_[index].set_destination(destination); |
| |
| // This move's source may have changed due to swaps to resolve cycles and |
| // so it may now be the last move in the cycle. If so remove it. |
| if (moves_[index].source()->Equals(destination)) { |
| moves_[index].Eliminate(); |
| return; |
| } |
| |
| // The move may be blocked on a (at most one) pending move, in which case |
| // we have a cycle. Search for such a blocking move and perform a swap to |
| // resolve it. |
| for (int i = 0; i < moves_.length(); ++i) { |
| LMoveOperands other_move = moves_[i]; |
| if (other_move.Blocks(destination)) { |
| DCHECK(other_move.IsPending()); |
| EmitSwap(index); |
| return; |
| } |
| } |
| |
| // This move is not blocked. |
| EmitMove(index); |
| } |
| |
| |
| void LGapResolver::Verify() { |
| #ifdef ENABLE_SLOW_DCHECKS |
| // No operand should be the destination for more than one move. |
| for (int i = 0; i < moves_.length(); ++i) { |
| LOperand* destination = moves_[i].destination(); |
| for (int j = i + 1; j < moves_.length(); ++j) { |
| SLOW_DCHECK(!destination->Equals(moves_[j].destination())); |
| } |
| } |
| #endif |
| } |
| |
| |
| #define __ ACCESS_MASM(cgen_->masm()) |
| |
| |
| void LGapResolver::EmitMove(int index) { |
| LOperand* source = moves_[index].source(); |
| LOperand* destination = moves_[index].destination(); |
| |
| // Dispatch on the source and destination operand kinds. Not all |
| // combinations are possible. |
| if (source->IsRegister()) { |
| Register src = cgen_->ToRegister(source); |
| if (destination->IsRegister()) { |
| Register dst = cgen_->ToRegister(destination); |
| __ movp(dst, src); |
| } else { |
| DCHECK(destination->IsStackSlot()); |
| Operand dst = cgen_->ToOperand(destination); |
| __ movp(dst, src); |
| } |
| |
| } else if (source->IsStackSlot()) { |
| Operand src = cgen_->ToOperand(source); |
| if (destination->IsRegister()) { |
| Register dst = cgen_->ToRegister(destination); |
| __ movp(dst, src); |
| } else { |
| DCHECK(destination->IsStackSlot()); |
| Operand dst = cgen_->ToOperand(destination); |
| __ movp(kScratchRegister, src); |
| __ movp(dst, kScratchRegister); |
| } |
| |
| } else if (source->IsConstantOperand()) { |
| LConstantOperand* constant_source = LConstantOperand::cast(source); |
| if (destination->IsRegister()) { |
| Register dst = cgen_->ToRegister(destination); |
| if (cgen_->IsSmiConstant(constant_source)) { |
| __ Move(dst, cgen_->ToSmi(constant_source)); |
| } else if (cgen_->IsInteger32Constant(constant_source)) { |
| int32_t constant = cgen_->ToInteger32(constant_source); |
| // Do sign extension only for constant used as de-hoisted array key. |
| // Others only need zero extension, which saves 2 bytes. |
| if (cgen_->IsDehoistedKeyConstant(constant_source)) { |
| __ Set(dst, constant); |
| } else { |
| __ Set(dst, static_cast<uint32_t>(constant)); |
| } |
| } else { |
| __ Move(dst, cgen_->ToHandle(constant_source)); |
| } |
| } else if (destination->IsDoubleRegister()) { |
| double v = cgen_->ToDouble(constant_source); |
| uint64_t int_val = bit_cast<uint64_t, double>(v); |
| XMMRegister dst = cgen_->ToDoubleRegister(destination); |
| if (int_val == 0) { |
| __ xorps(dst, dst); |
| } else { |
| __ Set(kScratchRegister, int_val); |
| __ movq(dst, kScratchRegister); |
| } |
| } else { |
| DCHECK(destination->IsStackSlot()); |
| Operand dst = cgen_->ToOperand(destination); |
| if (cgen_->IsSmiConstant(constant_source)) { |
| __ Move(dst, cgen_->ToSmi(constant_source)); |
| } else if (cgen_->IsInteger32Constant(constant_source)) { |
| // Do sign extension to 64 bits when stored into stack slot. |
| __ movp(dst, Immediate(cgen_->ToInteger32(constant_source))); |
| } else { |
| __ Move(kScratchRegister, cgen_->ToHandle(constant_source)); |
| __ movp(dst, kScratchRegister); |
| } |
| } |
| |
| } else if (source->IsDoubleRegister()) { |
| XMMRegister src = cgen_->ToDoubleRegister(source); |
| if (destination->IsDoubleRegister()) { |
| __ movaps(cgen_->ToDoubleRegister(destination), src); |
| } else { |
| DCHECK(destination->IsDoubleStackSlot()); |
| __ movsd(cgen_->ToOperand(destination), src); |
| } |
| } else if (source->IsDoubleStackSlot()) { |
| Operand src = cgen_->ToOperand(source); |
| if (destination->IsDoubleRegister()) { |
| __ movsd(cgen_->ToDoubleRegister(destination), src); |
| } else { |
| DCHECK(destination->IsDoubleStackSlot()); |
| __ movsd(xmm0, src); |
| __ movsd(cgen_->ToOperand(destination), xmm0); |
| } |
| } else { |
| UNREACHABLE(); |
| } |
| |
| moves_[index].Eliminate(); |
| } |
| |
| |
| void LGapResolver::EmitSwap(int index) { |
| LOperand* source = moves_[index].source(); |
| LOperand* destination = moves_[index].destination(); |
| |
| // Dispatch on the source and destination operand kinds. Not all |
| // combinations are possible. |
| if (source->IsRegister() && destination->IsRegister()) { |
| // Swap two general-purpose registers. |
| Register src = cgen_->ToRegister(source); |
| Register dst = cgen_->ToRegister(destination); |
| __ xchgq(dst, src); |
| |
| } else if ((source->IsRegister() && destination->IsStackSlot()) || |
| (source->IsStackSlot() && destination->IsRegister())) { |
| // Swap a general-purpose register and a stack slot. |
| Register reg = |
| cgen_->ToRegister(source->IsRegister() ? source : destination); |
| Operand mem = |
| cgen_->ToOperand(source->IsRegister() ? destination : source); |
| __ movp(kScratchRegister, mem); |
| __ movp(mem, reg); |
| __ movp(reg, kScratchRegister); |
| |
| } else if ((source->IsStackSlot() && destination->IsStackSlot()) || |
| (source->IsDoubleStackSlot() && destination->IsDoubleStackSlot())) { |
| // Swap two stack slots or two double stack slots. |
| Operand src = cgen_->ToOperand(source); |
| Operand dst = cgen_->ToOperand(destination); |
| __ movsd(xmm0, src); |
| __ movp(kScratchRegister, dst); |
| __ movsd(dst, xmm0); |
| __ movp(src, kScratchRegister); |
| |
| } else if (source->IsDoubleRegister() && destination->IsDoubleRegister()) { |
| // Swap two double registers. |
| XMMRegister source_reg = cgen_->ToDoubleRegister(source); |
| XMMRegister destination_reg = cgen_->ToDoubleRegister(destination); |
| __ movaps(xmm0, source_reg); |
| __ movaps(source_reg, destination_reg); |
| __ movaps(destination_reg, xmm0); |
| |
| } else if (source->IsDoubleRegister() || destination->IsDoubleRegister()) { |
| // Swap a double register and a double stack slot. |
| DCHECK((source->IsDoubleRegister() && destination->IsDoubleStackSlot()) || |
| (source->IsDoubleStackSlot() && destination->IsDoubleRegister())); |
| XMMRegister reg = cgen_->ToDoubleRegister(source->IsDoubleRegister() |
| ? source |
| : destination); |
| LOperand* other = source->IsDoubleRegister() ? destination : source; |
| DCHECK(other->IsDoubleStackSlot()); |
| Operand other_operand = cgen_->ToOperand(other); |
| __ movsd(xmm0, other_operand); |
| __ movsd(other_operand, reg); |
| __ movaps(reg, xmm0); |
| |
| } else { |
| // No other combinations are possible. |
| UNREACHABLE(); |
| } |
| |
| // The swap of source and destination has executed a move from source to |
| // destination. |
| moves_[index].Eliminate(); |
| |
| // Any unperformed (including pending) move with a source of either |
| // this move's source or destination needs to have their source |
| // changed to reflect the state of affairs after the swap. |
| for (int i = 0; i < moves_.length(); ++i) { |
| LMoveOperands other_move = moves_[i]; |
| if (other_move.Blocks(source)) { |
| moves_[i].set_source(destination); |
| } else if (other_move.Blocks(destination)) { |
| moves_[i].set_source(source); |
| } |
| } |
| } |
| |
| #undef __ |
| |
| } } // namespace v8::internal |
| |
| #endif // V8_TARGET_ARCH_X64 |