Enables per-function far-branches for ARM and MIPS.

runtime/vm/assembler_ia32.h

Index: runtime/vm/assembler_ia32.h
===================================================================
--- runtime/vm/assembler_ia32.h	(revision 25620)
+++ runtime/vm/assembler_ia32.h	(working copy)
@@ -307,11 +307,14 @@
 
 class Assembler : public ValueObject {
  public:
-  Assembler()
+  explicit Assembler(bool use_far_branches = false)
       : buffer_(),
         object_pool_(GrowableObjectArray::Handle()),
         prologue_offset_(-1),
-        comments_() { }
+        comments_() {
+    // This mode is only needed and implemented for MIPS and ARM.
+    ASSERT(!use_far_branches);

[srdjan, 2013/07/31 22:52:27]

I would not assert at all, does not matter if we pass true or false.

[zra, 2013/08/01 00:28:32]

I like it as a check that the loop/logic in the compiler in
CompileParsedFunctionHelper is correct. For ARM and MIPS, If there is a logic
error, I could be passing true all the time and never notice, but then if I run
on ia32, It'll fail immediately.

+  }
   ~Assembler() { }
 
   static const bool kNearJump = true;