src/arm64/lithium-gap-resolver-arm64.cc - platform/external/chromium_org/v8 - Git at Google

 // Copyright 2013 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"

 #include "src/arm64/delayed-masm-arm64-inl.h"
 #include "src/arm64/lithium-codegen-arm64.h"
 #include "src/arm64/lithium-gap-resolver-arm64.h"

 namespace v8 {
 namespace internal {

 #define __ ACCESS_MASM((&masm_))


 void DelayedGapMasm::EndDelayedUse() {
   DelayedMasm::EndDelayedUse();
   if (scratch_register_used()) {
     DCHECK(ScratchRegister().Is(root));
     DCHECK(!pending());
     InitializeRootRegister();
     reset_scratch_register_used();
   }
 }


 LGapResolver::LGapResolver(LCodeGen* owner)
     : cgen_(owner), masm_(owner, owner->masm()), moves_(32, owner->zone()),
       root_index_(0), in_cycle_(false), saved_destination_(NULL) {
 }


 void LGapResolver::Resolve(LParallelMove* parallel_move) {
   DCHECK(moves_.is_empty());
   DCHECK(!masm_.pending());

   // 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 we reach this move again.
       PerformMove(i);
       if (in_cycle_) RestoreValue();
     }
   }

   // Perform the moves with constant sources.
   for (int i = 0; i < moves_.length(); ++i) {
     LMoveOperands move = moves_[i];

     if (!move.IsEliminated()) {
       DCHECK(move.source()->IsConstantOperand());
       EmitMove(i);
     }
   }

   __ EndDelayedUse();

   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.
   LMoveOperands& current_move = moves_[index];

   DCHECK(!current_move.IsPending());
   DCHECK(!current_move.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(current_move.source() != NULL);  // Otherwise it will look eliminated.
   LOperand* destination = current_move.destination();
   current_move.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.
   current_move.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) {
   DCHECK(moves_[index].destination()->Equals(moves_[root_index_].source()));
   DCHECK(!in_cycle_);

   // 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.
   in_cycle_ = true;
   LOperand* source = moves_[index].source();
   saved_destination_ = moves_[index].destination();

   if (source->IsRegister()) {
     AcquireSavedValueRegister();
     __ Mov(SavedValueRegister(), cgen_->ToRegister(source));
   } else if (source->IsStackSlot()) {
     AcquireSavedValueRegister();
     __ Load(SavedValueRegister(), cgen_->ToMemOperand(source));
   } else if (source->IsDoubleRegister()) {
     __ Fmov(SavedFPValueRegister(), cgen_->ToDoubleRegister(source));
   } else if (source->IsDoubleStackSlot()) {
     __ Load(SavedFPValueRegister(), cgen_->ToMemOperand(source));
   } else {
     UNREACHABLE();
   }

   // Mark this move as resolved.
   // This move will be actually performed by moving the saved value to this
   // move's destination in LGapResolver::RestoreValue().
   moves_[index].Eliminate();
 }


 void LGapResolver::RestoreValue() {
   DCHECK(in_cycle_);
   DCHECK(saved_destination_ != NULL);

   if (saved_destination_->IsRegister()) {
     __ Mov(cgen_->ToRegister(saved_destination_), SavedValueRegister());
     ReleaseSavedValueRegister();
   } else if (saved_destination_->IsStackSlot()) {
     __ Store(SavedValueRegister(), cgen_->ToMemOperand(saved_destination_));
     ReleaseSavedValueRegister();
   } else if (saved_destination_->IsDoubleRegister()) {
     __ Fmov(cgen_->ToDoubleRegister(saved_destination_),
             SavedFPValueRegister());
   } else if (saved_destination_->IsDoubleStackSlot()) {
     __ Store(SavedFPValueRegister(), 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());
       __ Store(source_register, cgen_->ToMemOperand(destination));
     }

   } else if (source->IsStackSlot()) {
     MemOperand source_operand = cgen_->ToMemOperand(source);
     if (destination->IsRegister()) {
       __ Load(cgen_->ToRegister(destination), source_operand);
     } else {
       DCHECK(destination->IsStackSlot());
       EmitStackSlotMove(index);
     }

   } else if (source->IsConstantOperand()) {
     LConstantOperand* constant_source = LConstantOperand::cast(source);
     if (destination->IsRegister()) {
       Register dst = cgen_->ToRegister(destination);
       if (cgen_->IsSmi(constant_source)) {
         __ Mov(dst, cgen_->ToSmi(constant_source));
       } else if (cgen_->IsInteger32Constant(constant_source)) {
         __ Mov(dst, cgen_->ToInteger32(constant_source));
       } else {
         __ LoadObject(dst, cgen_->ToHandle(constant_source));
       }
     } else if (destination->IsDoubleRegister()) {
       DoubleRegister result = cgen_->ToDoubleRegister(destination);
       __ Fmov(result, cgen_->ToDouble(constant_source));
     } else {
       DCHECK(destination->IsStackSlot());
       DCHECK(!in_cycle_);  // Constant moves happen after all cycles are gone.
       if (cgen_->IsSmi(constant_source)) {
         Smi* smi = cgen_->ToSmi(constant_source);
         __ StoreConstant(reinterpret_cast<intptr_t>(smi),
                          cgen_->ToMemOperand(destination));
       } else if (cgen_->IsInteger32Constant(constant_source)) {
         __ StoreConstant(cgen_->ToInteger32(constant_source),
                          cgen_->ToMemOperand(destination));
       } else {
         Handle<Object> handle = cgen_->ToHandle(constant_source);
         AllowDeferredHandleDereference smi_object_check;
         if (handle->IsSmi()) {
           Object* obj = *handle;
           DCHECK(!obj->IsHeapObject());
           __ StoreConstant(reinterpret_cast<intptr_t>(obj),
                            cgen_->ToMemOperand(destination));
         } else {
           AcquireSavedValueRegister();
           __ LoadObject(SavedValueRegister(), handle);
           __ Store(SavedValueRegister(), cgen_->ToMemOperand(destination));
           ReleaseSavedValueRegister();
         }
       }
     }

   } else if (source->IsDoubleRegister()) {
     DoubleRegister src = cgen_->ToDoubleRegister(source);
     if (destination->IsDoubleRegister()) {
       __ Fmov(cgen_->ToDoubleRegister(destination), src);
     } else {
       DCHECK(destination->IsDoubleStackSlot());
       __ Store(src, cgen_->ToMemOperand(destination));
     }

   } else if (source->IsDoubleStackSlot()) {
     MemOperand src = cgen_->ToMemOperand(source);
     if (destination->IsDoubleRegister()) {
       __ Load(cgen_->ToDoubleRegister(destination), src);
     } else {
       DCHECK(destination->IsDoubleStackSlot());
       EmitStackSlotMove(index);
     }

   } else {
     UNREACHABLE();
   }

   // The move has been emitted, we can eliminate it.
   moves_[index].Eliminate();
 }

 } }  // namespace v8::internal
	// Copyright 2013 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"

	#include "src/arm64/delayed-masm-arm64-inl.h"
	#include "src/arm64/lithium-codegen-arm64.h"
	#include "src/arm64/lithium-gap-resolver-arm64.h"

	namespace v8 {
	namespace internal {

	#define __ ACCESS_MASM((&masm_))


	void DelayedGapMasm::EndDelayedUse() {
	DelayedMasm::EndDelayedUse();
	if (scratch_register_used()) {
	DCHECK(ScratchRegister().Is(root));
	DCHECK(!pending());
	InitializeRootRegister();
	reset_scratch_register_used();
	}
	}


	LGapResolver::LGapResolver(LCodeGen* owner)
	: cgen_(owner), masm_(owner, owner->masm()), moves_(32, owner->zone()),
	root_index_(0), in_cycle_(false), saved_destination_(NULL) {
	}


	void LGapResolver::Resolve(LParallelMove* parallel_move) {
	DCHECK(moves_.is_empty());
	DCHECK(!masm_.pending());

	// 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 we reach this move again.
	PerformMove(i);
	if (in_cycle_) RestoreValue();
	}
	}

	// Perform the moves with constant sources.
	for (int i = 0; i < moves_.length(); ++i) {
	LMoveOperands move = moves_[i];

	if (!move.IsEliminated()) {
	DCHECK(move.source()->IsConstantOperand());
	EmitMove(i);
	}
	}

	__ EndDelayedUse();

	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.
	LMoveOperands& current_move = moves_[index];

	DCHECK(!current_move.IsPending());
	DCHECK(!current_move.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(current_move.source() != NULL); // Otherwise it will look eliminated.
	LOperand* destination = current_move.destination();
	current_move.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.
	current_move.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) {
	DCHECK(moves_[index].destination()->Equals(moves_[root_index_].source()));
	DCHECK(!in_cycle_);

	// 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.
	in_cycle_ = true;
	LOperand* source = moves_[index].source();
	saved_destination_ = moves_[index].destination();

	if (source->IsRegister()) {
	AcquireSavedValueRegister();
	__ Mov(SavedValueRegister(), cgen_->ToRegister(source));
	} else if (source->IsStackSlot()) {
	AcquireSavedValueRegister();
	__ Load(SavedValueRegister(), cgen_->ToMemOperand(source));
	} else if (source->IsDoubleRegister()) {
	__ Fmov(SavedFPValueRegister(), cgen_->ToDoubleRegister(source));
	} else if (source->IsDoubleStackSlot()) {
	__ Load(SavedFPValueRegister(), cgen_->ToMemOperand(source));
	} else {
	UNREACHABLE();
	}

	// Mark this move as resolved.
	// This move will be actually performed by moving the saved value to this
	// move's destination in LGapResolver::RestoreValue().
	moves_[index].Eliminate();
	}


	void LGapResolver::RestoreValue() {
	DCHECK(in_cycle_);
	DCHECK(saved_destination_ != NULL);

	if (saved_destination_->IsRegister()) {
	__ Mov(cgen_->ToRegister(saved_destination_), SavedValueRegister());
	ReleaseSavedValueRegister();
	} else if (saved_destination_->IsStackSlot()) {
	__ Store(SavedValueRegister(), cgen_->ToMemOperand(saved_destination_));
	ReleaseSavedValueRegister();
	} else if (saved_destination_->IsDoubleRegister()) {
	__ Fmov(cgen_->ToDoubleRegister(saved_destination_),
	SavedFPValueRegister());
	} else if (saved_destination_->IsDoubleStackSlot()) {
	__ Store(SavedFPValueRegister(), 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());
	__ Store(source_register, cgen_->ToMemOperand(destination));
	}

	} else if (source->IsStackSlot()) {
	MemOperand source_operand = cgen_->ToMemOperand(source);
	if (destination->IsRegister()) {
	__ Load(cgen_->ToRegister(destination), source_operand);
	} else {
	DCHECK(destination->IsStackSlot());
	EmitStackSlotMove(index);
	}

	} else if (source->IsConstantOperand()) {
	LConstantOperand* constant_source = LConstantOperand::cast(source);
	if (destination->IsRegister()) {
	Register dst = cgen_->ToRegister(destination);
	if (cgen_->IsSmi(constant_source)) {
	__ Mov(dst, cgen_->ToSmi(constant_source));
	} else if (cgen_->IsInteger32Constant(constant_source)) {
	__ Mov(dst, cgen_->ToInteger32(constant_source));
	} else {
	__ LoadObject(dst, cgen_->ToHandle(constant_source));
	}
	} else if (destination->IsDoubleRegister()) {
	DoubleRegister result = cgen_->ToDoubleRegister(destination);
	__ Fmov(result, cgen_->ToDouble(constant_source));
	} else {
	DCHECK(destination->IsStackSlot());
	DCHECK(!in_cycle_); // Constant moves happen after all cycles are gone.
	if (cgen_->IsSmi(constant_source)) {
	Smi* smi = cgen_->ToSmi(constant_source);
	__ StoreConstant(reinterpret_cast<intptr_t>(smi),
	cgen_->ToMemOperand(destination));
	} else if (cgen_->IsInteger32Constant(constant_source)) {
	__ StoreConstant(cgen_->ToInteger32(constant_source),
	cgen_->ToMemOperand(destination));
	} else {
	Handle<Object> handle = cgen_->ToHandle(constant_source);
	AllowDeferredHandleDereference smi_object_check;
	if (handle->IsSmi()) {
	Object* obj = *handle;
	DCHECK(!obj->IsHeapObject());
	__ StoreConstant(reinterpret_cast<intptr_t>(obj),
	cgen_->ToMemOperand(destination));
	} else {
	AcquireSavedValueRegister();
	__ LoadObject(SavedValueRegister(), handle);
	__ Store(SavedValueRegister(), cgen_->ToMemOperand(destination));
	ReleaseSavedValueRegister();
	}
	}
	}

	} else if (source->IsDoubleRegister()) {
	DoubleRegister src = cgen_->ToDoubleRegister(source);
	if (destination->IsDoubleRegister()) {
	__ Fmov(cgen_->ToDoubleRegister(destination), src);
	} else {
	DCHECK(destination->IsDoubleStackSlot());
	__ Store(src, cgen_->ToMemOperand(destination));
	}

	} else if (source->IsDoubleStackSlot()) {
	MemOperand src = cgen_->ToMemOperand(source);
	if (destination->IsDoubleRegister()) {
	__ Load(cgen_->ToDoubleRegister(destination), src);
	} else {
	DCHECK(destination->IsDoubleStackSlot());
	EmitStackSlotMove(index);
	}

	} else {
	UNREACHABLE();
	}

	// The move has been emitted, we can eliminate it.
	moves_[index].Eliminate();
	}

	} } // namespace v8::internal