Index: src/arm/lithium-gap-resolver-arm.cc |
diff --git a/src/arm/lithium-gap-resolver-arm.cc b/src/arm/lithium-gap-resolver-arm.cc |
deleted file mode 100644 |
index e1bd47b2ec034fed49e4dc7f5b061056029a703e..0000000000000000000000000000000000000000 |
--- a/src/arm/lithium-gap-resolver-arm.cc |
+++ /dev/null |
@@ -1,301 +0,0 @@ |
-// Copyright 2012 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/arm/lithium-codegen-arm.h" |
-#include "src/arm/lithium-gap-resolver-arm.h" |
- |
-namespace v8 { |
-namespace internal { |
- |
-// We use the root register to spill a value while breaking a cycle in parallel |
-// moves. We don't need access to roots while resolving the move list and using |
-// the root register has two advantages: |
-// - It is not in crankshaft allocatable registers list, so it can't interfere |
-// with any of the moves we are resolving. |
-// - We don't need to push it on the stack, as we can reload it with its value |
-// once we have resolved a cycle. |
-#define kSavedValueRegister kRootRegister |
- |
- |
-LGapResolver::LGapResolver(LCodeGen* owner) |
- : cgen_(owner), moves_(32, owner->zone()), root_index_(0), in_cycle_(false), |
- saved_destination_(NULL), need_to_restore_root_(false) { } |
- |
- |
-#define __ ACCESS_MASM(cgen_->masm()) |
- |
- |
-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()) { |
- root_index_ = i; // Any cycle is found when by reaching this move again. |
- PerformMove(i); |
- if (in_cycle_) { |
- RestoreValue(); |
- } |
- } |
- } |
- |
- // 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); |
- } |
- } |
- |
- if (need_to_restore_root_) { |
- DCHECK(kSavedValueRegister.is(kRootRegister)); |
- __ InitializeRootRegister(); |
- need_to_restore_root_ = false; |
- } |
- |
- 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 can only find a cycle, when doing a depth-first traversal of moves, |
- // be encountering the starting move again. So by spilling the source of |
- // the starting move, we break the cycle. All moves are then unblocked, |
- // and the starting move is completed by writing the spilled value to |
- // its destination. All other moves from the spilled source have been |
- // completed prior to breaking the cycle. |
- // An additional complication is that moves to MemOperands with large |
- // offsets (more than 1K or 4K) require us to spill this spilled value to |
- // the stack, to free up the register. |
- 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. Multiple moves can |
- // be pending because this function is recursive. |
- 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()) { |
- PerformMove(i); |
- // If there is a blocking, pending move it must be moves_[root_index_] |
- // and all other moves with the same source as moves_[root_index_] are |
- // sucessfully executed (because they are cycle-free) by this loop. |
- } |
- } |
- |
- // We are about to resolve this move and don't need it marked as |
- // pending, so restore its destination. |
- moves_[index].set_destination(destination); |
- |
- // The move may be blocked on a pending move, which must be the starting move. |
- // In this case, we have a cycle, and we save the source of this move to |
- // a scratch register to break it. |
- LMoveOperands other_move = moves_[root_index_]; |
- if (other_move.Blocks(destination)) { |
- DCHECK(other_move.IsPending()); |
- BreakCycle(index); |
- return; |
- } |
- |
- // This move is no longer 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 |
-} |
- |
- |
-void LGapResolver::BreakCycle(int index) { |
- // We save in a register the source of that move and we remember its |
- // destination. Then we mark this move as resolved so the cycle is |
- // broken and we can perform the other moves. |
- DCHECK(moves_[index].destination()->Equals(moves_[root_index_].source())); |
- DCHECK(!in_cycle_); |
- in_cycle_ = true; |
- LOperand* source = moves_[index].source(); |
- saved_destination_ = moves_[index].destination(); |
- if (source->IsRegister()) { |
- need_to_restore_root_ = true; |
- __ mov(kSavedValueRegister, cgen_->ToRegister(source)); |
- } else if (source->IsStackSlot()) { |
- need_to_restore_root_ = true; |
- __ ldr(kSavedValueRegister, cgen_->ToMemOperand(source)); |
- } else if (source->IsDoubleRegister()) { |
- __ vmov(kScratchDoubleReg, cgen_->ToDoubleRegister(source)); |
- } else if (source->IsDoubleStackSlot()) { |
- __ vldr(kScratchDoubleReg, cgen_->ToMemOperand(source)); |
- } else { |
- UNREACHABLE(); |
- } |
- // This move will be done by restoring the saved value to the destination. |
- moves_[index].Eliminate(); |
-} |
- |
- |
-void LGapResolver::RestoreValue() { |
- DCHECK(in_cycle_); |
- DCHECK(saved_destination_ != NULL); |
- |
- if (saved_destination_->IsRegister()) { |
- __ mov(cgen_->ToRegister(saved_destination_), kSavedValueRegister); |
- } else if (saved_destination_->IsStackSlot()) { |
- __ str(kSavedValueRegister, cgen_->ToMemOperand(saved_destination_)); |
- } else if (saved_destination_->IsDoubleRegister()) { |
- __ vmov(cgen_->ToDoubleRegister(saved_destination_), kScratchDoubleReg); |
- } else if (saved_destination_->IsDoubleStackSlot()) { |
- __ vstr(kScratchDoubleReg, cgen_->ToMemOperand(saved_destination_)); |
- } else { |
- UNREACHABLE(); |
- } |
- |
- in_cycle_ = false; |
- saved_destination_ = NULL; |
-} |
- |
- |
-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 source_register = cgen_->ToRegister(source); |
- if (destination->IsRegister()) { |
- __ mov(cgen_->ToRegister(destination), source_register); |
- } else { |
- DCHECK(destination->IsStackSlot()); |
- __ str(source_register, cgen_->ToMemOperand(destination)); |
- } |
- } else if (source->IsStackSlot()) { |
- MemOperand source_operand = cgen_->ToMemOperand(source); |
- if (destination->IsRegister()) { |
- __ ldr(cgen_->ToRegister(destination), source_operand); |
- } else { |
- DCHECK(destination->IsStackSlot()); |
- MemOperand destination_operand = cgen_->ToMemOperand(destination); |
- if (!destination_operand.OffsetIsUint12Encodable()) { |
- // ip is overwritten while saving the value to the destination. |
- // Therefore we can't use ip. It is OK if the read from the source |
- // destroys ip, since that happens before the value is read. |
- __ vldr(kScratchDoubleReg.low(), source_operand); |
- __ vstr(kScratchDoubleReg.low(), destination_operand); |
- } else { |
- __ ldr(ip, source_operand); |
- __ str(ip, destination_operand); |
- } |
- } |
- |
- } 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)) { |
- __ mov(dst, Operand(cgen_->ToRepresentation(constant_source, r))); |
- } else { |
- __ Move(dst, cgen_->ToHandle(constant_source)); |
- } |
- } else if (destination->IsDoubleRegister()) { |
- DwVfpRegister result = cgen_->ToDoubleRegister(destination); |
- double v = cgen_->ToDouble(constant_source); |
- __ Vmov(result, v, ip); |
- } else { |
- DCHECK(destination->IsStackSlot()); |
- DCHECK(!in_cycle_); // Constant moves happen after all cycles are gone. |
- need_to_restore_root_ = true; |
- Representation r = cgen_->IsSmi(constant_source) |
- ? Representation::Smi() : Representation::Integer32(); |
- if (cgen_->IsInteger32(constant_source)) { |
- __ mov(kSavedValueRegister, |
- Operand(cgen_->ToRepresentation(constant_source, r))); |
- } else { |
- __ Move(kSavedValueRegister, cgen_->ToHandle(constant_source)); |
- } |
- __ str(kSavedValueRegister, cgen_->ToMemOperand(destination)); |
- } |
- |
- } else if (source->IsDoubleRegister()) { |
- DwVfpRegister source_register = cgen_->ToDoubleRegister(source); |
- if (destination->IsDoubleRegister()) { |
- __ vmov(cgen_->ToDoubleRegister(destination), source_register); |
- } else { |
- DCHECK(destination->IsDoubleStackSlot()); |
- __ vstr(source_register, cgen_->ToMemOperand(destination)); |
- } |
- |
- } else if (source->IsDoubleStackSlot()) { |
- MemOperand source_operand = cgen_->ToMemOperand(source); |
- if (destination->IsDoubleRegister()) { |
- __ vldr(cgen_->ToDoubleRegister(destination), source_operand); |
- } else { |
- DCHECK(destination->IsDoubleStackSlot()); |
- MemOperand destination_operand = cgen_->ToMemOperand(destination); |
- if (in_cycle_) { |
- // kScratchDoubleReg was used to break the cycle. |
- __ vpush(kScratchDoubleReg); |
- __ vldr(kScratchDoubleReg, source_operand); |
- __ vstr(kScratchDoubleReg, destination_operand); |
- __ vpop(kScratchDoubleReg); |
- } else { |
- __ vldr(kScratchDoubleReg, source_operand); |
- __ vstr(kScratchDoubleReg, destination_operand); |
- } |
- } |
- } else { |
- UNREACHABLE(); |
- } |
- |
- moves_[index].Eliminate(); |
-} |
- |
- |
-#undef __ |
- |
-} // namespace internal |
-} // namespace v8 |