[Turbofan] Add concept of FP register aliasing on ARM 32.

src/compiler/instruction.h

 // Copyright 2014 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.
 
 #ifndef V8_COMPILER_INSTRUCTION_H_
 #define V8_COMPILER_INSTRUCTION_H_
 
 #include <deque>
 #include <iosfwd>
 #include <map>
@@ skipping 10 matching lines @@
 #include "src/register-configuration.h"
 #include "src/zone/zone-allocator.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 // Forward declarations.
 class Schedule;
 
-
-class InstructionOperand {
+class V8_EXPORT_PRIVATE InstructionOperand {
  public:
   static const int kInvalidVirtualRegister = -1;
 
   // TODO(dcarney): recover bit. INVALID can be represented as UNALLOCATED with
   // kInvalidVirtualRegister and some DCHECKS.
   enum Kind {
     INVALID,
     UNALLOCATED,
     CONSTANT,
     IMMEDIATE,
@@ skipping 69 matching lines @@
   }
 
   bool EqualsCanonicalized(const InstructionOperand& that) const {
     return this->GetCanonicalizedValue() == that.GetCanonicalizedValue();
   }
 
   bool CompareCanonicalized(const InstructionOperand& that) const {
     return this->GetCanonicalizedValue() < that.GetCanonicalizedValue();
   }
 
-  bool InterferesWith(const InstructionOperand& that) const;
+  bool InterferesWith(const InstructionOperand& other) const;
 
   // APIs to aid debugging. For general-stream APIs, use operator<<
   void Print(const RegisterConfiguration* config) const;
   void Print() const;
 
  protected:
   explicit InstructionOperand(Kind kind) : value_(KindField::encode(kind)) {}
 
   inline uint64_t GetCanonicalizedValue() const;
 
@@ skipping 501 matching lines @@
          LocationOperand::cast(this)->location_kind() ==
              LocationOperand::STACK_SLOT &&
          LocationOperand::cast(this)->representation() ==
              MachineRepresentation::kSimd128;
 }
 
 uint64_t InstructionOperand::GetCanonicalizedValue() const {
   if (IsAnyLocationOperand()) {
     MachineRepresentation canonical = MachineRepresentation::kNone;
     if (IsFPRegister()) {
-      // We treat all FP register operands the same for simple aliasing.
-      canonical = MachineRepresentation::kFloat64;
+      if (kSimpleFPAliasing) {
+        // We treat all FP register operands the same for simple aliasing.
+        canonical = MachineRepresentation::kFloat64;
+      } else {
+        // We need to distinguish FP register operands of different reps when
+        // aliasing is not simple (e.g. ARM).
+        canonical = LocationOperand::cast(this)->representation();
+      }
     }
     return InstructionOperand::KindField::update(
         LocationOperand::RepresentationField::update(this->value_, canonical),
         LocationOperand::EXPLICIT);
   }
   return this->value_;
 }
 
 // Required for maps that don't care about machine type.
 struct CompareOperandModuloType {
   bool operator()(const InstructionOperand& a,
                   const InstructionOperand& b) const {
     return a.CompareCanonicalized(b);
   }
 };
 
-
-class MoveOperands final : public ZoneObject {
+class V8_EXPORT_PRIVATE MoveOperands final : public ZoneObject {

[jochen (gone - plz use gerrit), 2016/10/25 11:56:07]

if you export a class, you have to annotated unexported base classes, i.e., here
it's

public NON_EXPORTED_BASE(ZoneObject) (defined in src/base/compiler-specific.h)

[bbudge, 2016/10/25 14:01:09]

Done. Here and below.

  public:
   MoveOperands(const InstructionOperand& source,
                const InstructionOperand& destination)
       : source_(source), destination_(destination) {
     DCHECK(!source.IsInvalid() && !destination.IsInvalid());
   }
 
   const InstructionOperand& source() const { return source_; }
   InstructionOperand& source() { return source_; }
   void set_source(const InstructionOperand& operand) { source_ = operand; }
 
   const InstructionOperand& destination() const { return destination_; }
   InstructionOperand& destination() { return destination_; }
   void set_destination(const InstructionOperand& operand) {
     destination_ = operand;
   }
 
   // The gap resolver marks moves as "in-progress" by clearing the
   // destination (but not the source).
   bool IsPending() const {
     return destination_.IsInvalid() && !source_.IsInvalid();
   }
   void SetPending() { destination_ = InstructionOperand(); }
 
-  // True if this move is a move into the given destination operand.
-  bool Blocks(const InstructionOperand& destination) const {
-    return !IsEliminated() && source().InterferesWith(destination);
-  }
-
   // A move is redundant if it's been eliminated or if its source and
   // destination are the same.
   bool IsRedundant() const {
     DCHECK_IMPLIES(!destination_.IsInvalid(), !destination_.IsConstant());
     return IsEliminated() || source_.EqualsCanonicalized(destination_);
   }
 
   // We clear both operands to indicate move that's been eliminated.
   void Eliminate() { source_ = destination_ = InstructionOperand(); }
   bool IsEliminated() const {
@@ skipping 14 matching lines @@
 
 
 struct PrintableMoveOperands {
   const RegisterConfiguration* register_configuration_;
   const MoveOperands* move_operands_;
 };
 
 
 std::ostream& operator<<(std::ostream& os, const PrintableMoveOperands& mo);
 
-
-class ParallelMove final : public ZoneVector<MoveOperands*>, public ZoneObject {
+class V8_EXPORT_PRIVATE ParallelMove final : public ZoneVector<MoveOperands *>,

[jochen (gone - plz use gerrit), 2016/10/25 11:56:07]

ZoneVector<T> is implemented as std::vector<T, zone_allocator<T>> or similar.
Since we haven't yet updated to MSVS 2015 (crbug.com/603131 ), the allocator
needs to have a default constructor.

If you add a constructor like zone_allocator() : zone_(nullptr) {} the error
should go away.

The allocator also needs to have a copy constructor, so maybe you'll need to
drop the "explicit" from the existing copy constructor.

[bbudge, 2016/10/25 14:01:09]

I stumbled on that fix in patchset #22 (adding a default constructor), but it
has to be public, which seems undesirable in this case. Should I add a TODO to
remove the ctor when we update to MSVS 2015?

Thanks for your help.

+                                             public ZoneObject {
  public:
   explicit ParallelMove(Zone* zone) : ZoneVector<MoveOperands*>(zone) {
     reserve(4);
   }
 
   MoveOperands* AddMove(const InstructionOperand& from,
                         const InstructionOperand& to) {
     Zone* zone = get_allocator().zone();
     return AddMove(from, to, zone);
   }
 
   MoveOperands* AddMove(const InstructionOperand& from,
                         const InstructionOperand& to,
                         Zone* operand_allocation_zone) {
     MoveOperands* move = new (operand_allocation_zone) MoveOperands(from, to);
     push_back(move);
     return move;
   }
 
   bool IsRedundant() const;
 
   // Prepare this ParallelMove to insert move as if it happened in a subsequent
-  // ParallelMove.  move->source() may be changed.  The MoveOperand returned
-  // must be Eliminated.
-  MoveOperands* PrepareInsertAfter(MoveOperands* move) const;
+  // ParallelMove.  move->source() may be changed.  Any MoveOperands added to
+  // to_eliminate must be Eliminated.
+  void PrepareInsertAfter(MoveOperands* move,
+                          ZoneVector<MoveOperands*>* to_eliminate) const;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ParallelMove);
 };
 
 
 struct PrintableParallelMove {
   const RegisterConfiguration* register_configuration_;
   const ParallelMove* parallel_move_;
 };
@@ skipping 771 matching lines @@
 };
 
 V8_EXPORT_PRIVATE std::ostream& operator<<(
     std::ostream& os, const PrintableInstructionSequence& code);
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_INSTRUCTION_H_