Cleanup deoptimization code to make it architecture independent (in progress).

runtime/vm/constants_arm.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_CONSTANTS_ARM_H_
 #define VM_CONSTANTS_ARM_H_
 
 #include "platform/assert.h"
 
 namespace dart {
@@ skipping 164 matching lines @@
 
 // Registers available to Dart that are not preserved by runtime calls.
 const RegList kDartVolatileCpuRegs =
     kDartAvailableCpuRegs & ~kAbiPreservedCpuRegs;
 const int kDartVolatileCpuRegCount = 4;
 const DRegister kDartFirstVolatileFpuReg = D0;
 const DRegister kDartLastVolatileFpuReg = D7;
 const int kDartVolatileFpuRegCount = 8;
 
 
+// TODO(regis): Move these constants to stack_frame_arm.h.
 // Dart stack frame layout.
-static const int kLastParamSlotIndex = 3;
-static const int kFirstLocalSlotIndex = -2;
+static const int kLastParamSlotIndex = 3;  // From fp.
+static const int kFirstLocalSlotIndex = -2;  // From fp.
+static const int kPcSlotIndexFromSp = -2;
 
+/* ARM Dart Frame Layout
+
+               |                   | <- TOS
+Callee frame   | ...               |
+               | current LR        |    (PC of current frame)
+               | PC Marker         |    (callee's frame code entry)
+               +-------------------+
+Current frame  | ...               | <- SP of current frame
+               | first local       |
+               | caller's PP       |
+               | caller's FP       | <- FP of current frame
+               | caller's LR       |    (PC of caller frame)
+               | PC Marker         |    (current frame's code entry)
+               +-------------------+
+Caller frame   | last parameter    |
+               |  ...              |
+*/
 
 // Values for the condition field as defined in section A3.2.
 enum Condition {
   kNoCondition = -1,
   EQ =  0,  // equal
   NE =  1,  // not equal
   CS =  2,  // carry set/unsigned higher or same
   CC =  3,  // carry clear/unsigned lower
   MI =  4,  // minus/negative
   PL =  5,  // plus/positive or zero
@@ skipping 368 matching lines @@
   static Instr* At(uword pc) { return reinterpret_cast<Instr*>(pc); }
 
  private:
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(Instr);
 };
 
 }  // namespace dart
 
 #endif  // VM_CONSTANTS_ARM_H_