Use GPRs for mints

runtime/vm/deopt_instructions.h

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_DEOPT_INSTRUCTIONS_H_
 #define VM_DEOPT_INSTRUCTIONS_H_
 
 #include "vm/allocation.h"
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
@@ skipping 40 matching lines @@
   intptr_t GetCallerFp() const;
   void SetCallerFp(intptr_t callers_fp);
 
   RawObject* ObjectAt(intptr_t index) const {
     const Array& object_table = Array::Handle(object_table_);
     return object_table.At(index);
   }
 
   intptr_t RegisterValue(Register reg) const {
     ASSERT(cpu_registers_ != NULL);
+    ASSERT(reg >= 0);
+    ASSERT(reg < kNumberOfCpuRegisters);
     return cpu_registers_[reg];
   }
 
   double FpuRegisterValue(FpuRegister reg) const {
     ASSERT(fpu_registers_ != NULL);
+    ASSERT(reg >= 0);
+    ASSERT(reg < kNumberOfFpuRegisters);
     return *reinterpret_cast<double*>(&fpu_registers_[reg]);
   }
 
   int64_t FpuRegisterValueAsInt64(FpuRegister reg) const {
     ASSERT(fpu_registers_ != NULL);
+    ASSERT(reg >= 0);
+    ASSERT(reg < kNumberOfFpuRegisters);
     return *reinterpret_cast<int64_t*>(&fpu_registers_[reg]);
   }
 
   simd128_value_t FpuRegisterValueAsSimd128(FpuRegister reg) const {
     ASSERT(fpu_registers_ != NULL);
+    ASSERT(reg >= 0);
+    ASSERT(reg < kNumberOfFpuRegisters);
     const float* address = reinterpret_cast<float*>(&fpu_registers_[reg]);
     return simd128_value_t().readFrom(address);
   }
 
   void set_dest_frame(intptr_t* dest_frame) {
     ASSERT(dest_frame != NULL && dest_frame_ == NULL);
     dest_frame_ = dest_frame;
   }
 
   Isolate* isolate() const { return isolate_; }
@@ skipping 123 matching lines @@
 // Represents one deopt instruction, e.g, setup return address, store object,
 // store register, etc. The target is defined by instruction's position in
 // the deopt-info array.
 class DeoptInstr : public ZoneAllocated {
  public:
   enum Kind {
     kRetAddress,
     kConstant,
     kRegister,
     kFpuRegister,
-    kInt64FpuRegister,
+    kInt64RegisterPair,

[regis, 2014/05/22 17:09:40]

Why not kRegisterPair?
kInt64RegisterPair sounds like a pair of 64-bit registers.

[Cutch, 2014/05/23 21:33:54]

A kInt64RegisterPair is a mint (64-bit integer) which is in two register
locations. 

A kInt64StackSlotPair is a mint which is in two stack slots.

A kInt64StackSlotRegister is a mint which has one half in a register location
and the other half in a stack location.

[regis, 2014/05/23 22:36:59]

Do I understand correctly that some of these are for 32-bit architectures only
and others for 64-bit architectures only?

Marking these as such would avoid confusion:
  kInt64RegisterPair,  // On 32-bit architectures only.
  kInt64StackSlot,  // On 64-bit architectures only.
  kInt64StackSlotPair,  // On 32-bit architectures only.
etc...

Maybe I still do not get it.
Let's chat next week.

     kFloat32x4FpuRegister,
     kFloat64x2FpuRegister,
     kInt32x4FpuRegister,
     kStackSlot,
     kDoubleStackSlot,
     kInt64StackSlot,
+    kInt64StackSlotPair,
     kFloat32x4StackSlot,
     kFloat64x2StackSlot,
     kInt32x4StackSlot,
+    kInt64StackSlotRegister,

[regis, 2014/05/22 17:09:40]

Comments would help here. What is the difference between a kInt64StackSlot, a
kInt64StackSlotPair, and a kInt64StackSlotRegister? I hope a kInt64StackSlotPair
is twice the size of a kInt64StackSlot, is it?

[Cutch, 2014/05/23 21:33:54]

See above.

     kPcMarker,
     kPp,
     kCallerFp,
     kCallerPp,
     kCallerPc,
     kSuffix,
     kMaterializedObjectRef,
     kMaterializeObject
   };
 
@@ skipping 143 matching lines @@
                        DeoptInfo* info,
                        Smi* reason);
 
  private:
   static const intptr_t kEntrySize = 3;
 };
 
 }  // namespace dart
 
 #endif  // VM_DEOPT_INSTRUCTIONS_H_