// Copyright 2012 the V8 project authors. All rights reserved.
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-// * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-// * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following
-// disclaimer in the documentation and/or other materials provided
-// with the distribution.
-// * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived
-// from this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
#include "v8.h"
namespace v8 {
namespace internal {
-static const Register kSavedValueRegister = { 9 };
+// 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) { }
+ saved_destination_(NULL), need_to_restore_root_(false) { }
+
+
+#define __ ACCESS_MASM(cgen_->masm())
void LGapResolver::Resolve(LParallelMove* parallel_move) {
}
}
+ if (need_to_restore_root_) {
+ ASSERT(kSavedValueRegister.is(kRootRegister));
+ __ InitializeRootRegister();
+ need_to_restore_root_ = false;
+ }
+
moves_.Rewind(0);
}
#endif
}
-#define __ ACCESS_MASM(cgen_->masm())
void LGapResolver::BreakCycle(int index) {
- // We save in a register the value that should end up in the source of
- // moves_[root_index]. After performing all moves in the tree rooted
- // in that move, we save the value to that source.
+ // 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.
ASSERT(moves_[index].destination()->Equals(moves_[root_index_].source()));
ASSERT(!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));
ASSERT(in_cycle_);
ASSERT(saved_destination_ != NULL);
- // Spilled value is in kSavedValueRegister or kSavedDoubleValueRegister.
if (saved_destination_->IsRegister()) {
__ mov(cgen_->ToRegister(saved_destination_), kSavedValueRegister);
} else if (saved_destination_->IsStackSlot()) {
} else {
ASSERT(destination->IsStackSlot());
MemOperand destination_operand = cgen_->ToMemOperand(destination);
- if (in_cycle_) {
- 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);
- }
+ 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(kSavedValueRegister, source_operand);
- __ str(kSavedValueRegister, destination_operand);
+ __ ldr(ip, source_operand);
+ __ str(ip, destination_operand);
}
}
} else {
ASSERT(destination->IsStackSlot());
ASSERT(!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));
+ __ Move(kSavedValueRegister, cgen_->ToHandle(constant_source));
}
__ str(kSavedValueRegister, cgen_->ToMemOperand(destination));
}
ASSERT(destination->IsDoubleStackSlot());
MemOperand destination_operand = cgen_->ToMemOperand(destination);
if (in_cycle_) {
- // kSavedDoubleValueRegister was used to break the cycle,
- // but kSavedValueRegister is free.
- MemOperand source_high_operand =
- cgen_->ToHighMemOperand(source);
- MemOperand destination_high_operand =
- cgen_->ToHighMemOperand(destination);
- __ ldr(kSavedValueRegister, source_operand);
- __ str(kSavedValueRegister, destination_operand);
- __ ldr(kSavedValueRegister, source_high_operand);
- __ str(kSavedValueRegister, destination_high_operand);
+ // kScratchDoubleReg was used to break the cycle.
+ __ vstm(db_w, sp, kScratchDoubleReg, kScratchDoubleReg);
+ __ vldr(kScratchDoubleReg, source_operand);
+ __ vstr(kScratchDoubleReg, destination_operand);
+ __ vldm(ia_w, sp, kScratchDoubleReg, kScratchDoubleReg);
} else {
__ vldr(kScratchDoubleReg, source_operand);
__ vstr(kScratchDoubleReg, destination_operand);
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