Use GPRs for mints

runtime/vm/deopt_instructions.h

Index: runtime/vm/deopt_instructions.h
diff --git a/runtime/vm/deopt_instructions.h b/runtime/vm/deopt_instructions.h
index 551d04302ba0761eea836b5496bb4b16cb785f36..23a5e970c614a6566aa28d6b6d14f4184447b18d 100644
--- a/runtime/vm/deopt_instructions.h
+++ b/runtime/vm/deopt_instructions.h
@@ -58,21 +58,29 @@ class DeoptContext {
 
   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);
   }
@@ -216,16 +224,18 @@ class DeoptInstr : public ZoneAllocated {
     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,