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Diffstat (limited to 'chromium/v8/src/x87/lithium-gap-resolver-x87.cc')
| -rw-r--r-- | chromium/v8/src/x87/lithium-gap-resolver-x87.cc | 445 |
1 files changed, 445 insertions, 0 deletions
diff --git a/chromium/v8/src/x87/lithium-gap-resolver-x87.cc b/chromium/v8/src/x87/lithium-gap-resolver-x87.cc new file mode 100644 index 00000000000..9ebfa3a22c2 --- /dev/null +++ b/chromium/v8/src/x87/lithium-gap-resolver-x87.cc @@ -0,0 +1,445 @@ +// 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_X87 + +#include "src/x87/lithium-gap-resolver-x87.h" +#include "src/x87/lithium-codegen-x87.h" + +namespace v8 { +namespace internal { + +LGapResolver::LGapResolver(LCodeGen* owner) + : cgen_(owner), + moves_(32, owner->zone()), + source_uses_(), + destination_uses_(), + spilled_register_(-1) {} + + +void LGapResolver::Resolve(LParallelMove* parallel_move) { + ASSERT(HasBeenReset()); + // 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()) { + ASSERT(moves_[i].source()->IsConstantOperand()); + EmitMove(i); + } + } + + Finish(); + ASSERT(HasBeenReset()); +} + + +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()) AddMove(move); + } + 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. + + ASSERT(!moves_[index].IsPending()); + ASSERT(!moves_[index].IsRedundant()); + + // Clear this move's destination to indicate a pending move. The actual + // destination is saved on the side. + ASSERT(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)) { + RemoveMove(index); + 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)) { + ASSERT(other_move.IsPending()); + EmitSwap(index); + return; + } + } + + // This move is not blocked. + EmitMove(index); +} + + +void LGapResolver::AddMove(LMoveOperands move) { + LOperand* source = move.source(); + if (source->IsRegister()) ++source_uses_[source->index()]; + + LOperand* destination = move.destination(); + if (destination->IsRegister()) ++destination_uses_[destination->index()]; + + moves_.Add(move, cgen_->zone()); +} + + +void LGapResolver::RemoveMove(int index) { + LOperand* source = moves_[index].source(); + if (source->IsRegister()) { + --source_uses_[source->index()]; + ASSERT(source_uses_[source->index()] >= 0); + } + + LOperand* destination = moves_[index].destination(); + if (destination->IsRegister()) { + --destination_uses_[destination->index()]; + ASSERT(destination_uses_[destination->index()] >= 0); + } + + moves_[index].Eliminate(); +} + + +int LGapResolver::CountSourceUses(LOperand* operand) { + int count = 0; + for (int i = 0; i < moves_.length(); ++i) { + if (!moves_[i].IsEliminated() && moves_[i].source()->Equals(operand)) { + ++count; + } + } + return count; +} + + +Register LGapResolver::GetFreeRegisterNot(Register reg) { + int skip_index = reg.is(no_reg) ? -1 : Register::ToAllocationIndex(reg); + for (int i = 0; i < Register::NumAllocatableRegisters(); ++i) { + if (source_uses_[i] == 0 && destination_uses_[i] > 0 && i != skip_index) { + return Register::FromAllocationIndex(i); + } + } + return no_reg; +} + + +bool LGapResolver::HasBeenReset() { + if (!moves_.is_empty()) return false; + if (spilled_register_ >= 0) return false; + + for (int i = 0; i < Register::NumAllocatableRegisters(); ++i) { + if (source_uses_[i] != 0) return false; + if (destination_uses_[i] != 0) return false; + } + return true; +} + + +void LGapResolver::Verify() { +#ifdef ENABLE_SLOW_ASSERTS + // 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_ASSERT(!destination->Equals(moves_[j].destination())); + } + } +#endif +} + + +#define __ ACCESS_MASM(cgen_->masm()) + +void LGapResolver::Finish() { + if (spilled_register_ >= 0) { + __ pop(Register::FromAllocationIndex(spilled_register_)); + spilled_register_ = -1; + } + moves_.Rewind(0); +} + + +void LGapResolver::EnsureRestored(LOperand* operand) { + if (operand->IsRegister() && operand->index() == spilled_register_) { + __ pop(Register::FromAllocationIndex(spilled_register_)); + spilled_register_ = -1; + } +} + + +Register LGapResolver::EnsureTempRegister() { + // 1. We may have already spilled to create a temp register. + if (spilled_register_ >= 0) { + return Register::FromAllocationIndex(spilled_register_); + } + + // 2. We may have a free register that we can use without spilling. + Register free = GetFreeRegisterNot(no_reg); + if (!free.is(no_reg)) return free; + + // 3. Prefer to spill a register that is not used in any remaining move + // because it will not need to be restored until the end. + for (int i = 0; i < Register::NumAllocatableRegisters(); ++i) { + if (source_uses_[i] == 0 && destination_uses_[i] == 0) { + Register scratch = Register::FromAllocationIndex(i); + __ push(scratch); + spilled_register_ = i; + return scratch; + } + } + + // 4. Use an arbitrary register. Register 0 is as arbitrary as any other. + Register scratch = Register::FromAllocationIndex(0); + __ push(scratch); + spilled_register_ = 0; + return scratch; +} + + +void LGapResolver::EmitMove(int index) { + LOperand* source = moves_[index].source(); + LOperand* destination = moves_[index].destination(); + EnsureRestored(source); + EnsureRestored(destination); + + // Dispatch on the source and destination operand kinds. Not all + // combinations are possible. + if (source->IsRegister()) { + ASSERT(destination->IsRegister() || destination->IsStackSlot()); + Register src = cgen_->ToRegister(source); + Operand dst = cgen_->ToOperand(destination); + __ mov(dst, src); + + } else if (source->IsStackSlot()) { + ASSERT(destination->IsRegister() || destination->IsStackSlot()); + Operand src = cgen_->ToOperand(source); + if (destination->IsRegister()) { + Register dst = cgen_->ToRegister(destination); + __ mov(dst, src); + } else { + // Spill on demand to use a temporary register for memory-to-memory + // moves. + Register tmp = EnsureTempRegister(); + Operand dst = cgen_->ToOperand(destination); + __ mov(tmp, src); + __ mov(dst, tmp); + } + + } else if (source->IsConstantOperand()) { + LConstantOperand* constant_source = LConstantOperand::cast(source); + if (destination->IsRegister()) { + Register dst = cgen_->ToRegister(destination); + Representation r = cgen_->IsSmi(constant_source) + ? Representation::Smi() : Representation::Integer32(); + if (cgen_->IsInteger32(constant_source)) { + __ Move(dst, cgen_->ToImmediate(constant_source, r)); + } else { + __ LoadObject(dst, cgen_->ToHandle(constant_source)); + } + } else if (destination->IsDoubleRegister()) { + double v = cgen_->ToDouble(constant_source); + uint64_t int_val = BitCast<uint64_t, double>(v); + int32_t lower = static_cast<int32_t>(int_val); + int32_t upper = static_cast<int32_t>(int_val >> kBitsPerInt); + __ push(Immediate(upper)); + __ push(Immediate(lower)); + X87Register dst = cgen_->ToX87Register(destination); + cgen_->X87Mov(dst, MemOperand(esp, 0)); + __ add(esp, Immediate(kDoubleSize)); + } else { + ASSERT(destination->IsStackSlot()); + Operand dst = cgen_->ToOperand(destination); + Representation r = cgen_->IsSmi(constant_source) + ? Representation::Smi() : Representation::Integer32(); + if (cgen_->IsInteger32(constant_source)) { + __ Move(dst, cgen_->ToImmediate(constant_source, r)); + } else { + Register tmp = EnsureTempRegister(); + __ LoadObject(tmp, cgen_->ToHandle(constant_source)); + __ mov(dst, tmp); + } + } + + } else if (source->IsDoubleRegister()) { + // load from the register onto the stack, store in destination, which must + // be a double stack slot in the non-SSE2 case. + ASSERT(destination->IsDoubleStackSlot()); + Operand dst = cgen_->ToOperand(destination); + X87Register src = cgen_->ToX87Register(source); + cgen_->X87Mov(dst, src); + } else if (source->IsDoubleStackSlot()) { + // load from the stack slot on top of the floating point stack, and then + // store in destination. If destination is a double register, then it + // represents the top of the stack and nothing needs to be done. + if (destination->IsDoubleStackSlot()) { + Register tmp = EnsureTempRegister(); + Operand src0 = cgen_->ToOperand(source); + Operand src1 = cgen_->HighOperand(source); + Operand dst0 = cgen_->ToOperand(destination); + Operand dst1 = cgen_->HighOperand(destination); + __ mov(tmp, src0); // Then use tmp to copy source to destination. + __ mov(dst0, tmp); + __ mov(tmp, src1); + __ mov(dst1, tmp); + } else { + Operand src = cgen_->ToOperand(source); + X87Register dst = cgen_->ToX87Register(destination); + cgen_->X87Mov(dst, src); + } + } else { + UNREACHABLE(); + } + + RemoveMove(index); +} + + +void LGapResolver::EmitSwap(int index) { + LOperand* source = moves_[index].source(); + LOperand* destination = moves_[index].destination(); + EnsureRestored(source); + EnsureRestored(destination); + + // Dispatch on the source and destination operand kinds. Not all + // combinations are possible. + if (source->IsRegister() && destination->IsRegister()) { + // Register-register. + Register src = cgen_->ToRegister(source); + Register dst = cgen_->ToRegister(destination); + __ xchg(dst, src); + + } else if ((source->IsRegister() && destination->IsStackSlot()) || + (source->IsStackSlot() && destination->IsRegister())) { + // Register-memory. Use a free register as a temp if possible. Do not + // spill on demand because the simple spill implementation cannot avoid + // spilling src at this point. + Register tmp = GetFreeRegisterNot(no_reg); + Register reg = + cgen_->ToRegister(source->IsRegister() ? source : destination); + Operand mem = + cgen_->ToOperand(source->IsRegister() ? destination : source); + if (tmp.is(no_reg)) { + __ xor_(reg, mem); + __ xor_(mem, reg); + __ xor_(reg, mem); + } else { + __ mov(tmp, mem); + __ mov(mem, reg); + __ mov(reg, tmp); + } + + } else if (source->IsStackSlot() && destination->IsStackSlot()) { + // Memory-memory. Spill on demand to use a temporary. If there is a + // free register after that, use it as a second temporary. + Register tmp0 = EnsureTempRegister(); + Register tmp1 = GetFreeRegisterNot(tmp0); + Operand src = cgen_->ToOperand(source); + Operand dst = cgen_->ToOperand(destination); + if (tmp1.is(no_reg)) { + // Only one temp register available to us. + __ mov(tmp0, dst); + __ xor_(tmp0, src); + __ xor_(src, tmp0); + __ xor_(tmp0, src); + __ mov(dst, tmp0); + } else { + __ mov(tmp0, dst); + __ mov(tmp1, src); + __ mov(dst, tmp1); + __ mov(src, tmp0); + } + } else { + // No other combinations are possible. + UNREACHABLE(); + } + + // The swap of source and destination has executed a move from source to + // destination. + RemoveMove(index); + + // 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); + } + } + + // In addition to swapping the actual uses as sources, we need to update + // the use counts. + if (source->IsRegister() && destination->IsRegister()) { + int temp = source_uses_[source->index()]; + source_uses_[source->index()] = source_uses_[destination->index()]; + source_uses_[destination->index()] = temp; + } else if (source->IsRegister()) { + // We don't have use counts for non-register operands like destination. + // Compute those counts now. + source_uses_[source->index()] = CountSourceUses(source); + } else if (destination->IsRegister()) { + source_uses_[destination->index()] = CountSourceUses(destination); + } +} + +#undef __ + +} } // namespace v8::internal + +#endif // V8_TARGET_ARCH_X87 |