Adds support for ARMv6.

runtime/vm/assembler_arm.h

Index: runtime/vm/assembler_arm.h
===================================================================
--- runtime/vm/assembler_arm.h	(revision 33351)
+++ runtime/vm/assembler_arm.h	(working copy)
@@ -63,6 +63,7 @@
   DISALLOW_COPY_AND_ASSIGN(Label);
 };
 
+
 // Encodes Addressing Mode 1 - Data-processing operands.
 class ShifterOperand : public ValueObject {
  public:
@@ -590,6 +591,7 @@
                      DRegister tmpl, DRegister tmpr);
 
   // Load and Store. May clobber IP.
+  void LoadLargeImmediate(Register rd, int32_t value, Condition cond = AL);

[regis, 2014/03/06 17:32:11]

The function LoadImmediate below is also able to load a large immediate value.
The key here is not that you load a large immediate, but that you can decode the
emitted instructions, or that you can patch the immediate value.
Instead of adding LoadLargeImmediate, I would add 2 functions for clarity:
LoadDecodableImmediate and LoadPatchableImmediate.
On ARMv6, LoadDecodableImmediate would forward to LoadPatchableImmediate (same
code as in your LoadLargeImmediate).
On ARMv7, LoadDecodableImmediate would emit movw and optionally movt, whereas
LoadPatchableImmediate would always emit both movw and movt.

[zra, 2014/03/07 19:00:17]

Done.

   void LoadImmediate(Register rd, int32_t value, Condition cond = AL);
   void LoadSImmediate(SRegister sd, float value, Condition cond = AL);
   void LoadDImmediate(DRegister dd, double value,
@@ -755,6 +757,9 @@
   int32_t AddObject(const Object& obj);
   int32_t AddExternalLabel(const ExternalLabel* label);
 
+  void BindARMv6(Label* label);
+  void BindARMv7(Label* label);
+
   class CodeComment : public ZoneAllocated {
    public:
     CodeComment(intptr_t pc_offset, const String& comment)