Add "has fast elements" bit to maps and use it in inlined keyed loads.

src/arm/macro-assembler-arm.cc

 // Copyright 2006-2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1530 matching lines @@
 void MacroAssembler::Check(Condition cc, const char* msg) {
   Label L;
   b(cc, &L);
   Abort(msg);
   // will not return here
   bind(&L);
 }
 
 
 void MacroAssembler::Abort(const char* msg) {
+  Label abort_start;
+  bind(&abort_start);
   // We want to pass the msg string like a smi to avoid GC
   // problems, however msg is not guaranteed to be aligned
   // properly. Instead, we pass an aligned pointer that is
   // a proper v8 smi, but also pass the alignment difference
   // from the real pointer as a smi.
   intptr_t p1 = reinterpret_cast<intptr_t>(msg);
   intptr_t p0 = (p1 & ~kSmiTagMask) + kSmiTag;
   ASSERT(reinterpret_cast<Object*>(p0)->IsSmi());
 #ifdef DEBUG
   if (msg != NULL) {
     RecordComment("Abort message: ");
     RecordComment(msg);
   }
 #endif
   // Disable stub call restrictions to always allow calls to abort.
   set_allow_stub_calls(true);
 
   mov(r0, Operand(p0));
   push(r0);
   mov(r0, Operand(Smi::FromInt(p1 - p0)));
   push(r0);
   CallRuntime(Runtime::kAbort, 2);
   // will not return here
+  if (is_const_pool_blocked()) {
+    // If the calling code cares about the exact number of
+    // instructions generated, we insert padding here to keep the size
+    // of the Abort macro constant.
+    static const int kExpectedAbortInstructions = 10;
+    int abort_instructions = InstructionsGeneratedSince(&abort_start);
+    ASSERT(abort_instructions <= kExpectedAbortInstructions);
+    while (abort_instructions++ < kExpectedAbortInstructions) {
+      nop();
+    }
+  }
 }
 
 
 void MacroAssembler::LoadContext(Register dst, int context_chain_length) {
   if (context_chain_length > 0) {
     // Move up the chain of contexts to the context containing the slot.
     ldr(dst, MemOperand(cp, Context::SlotOffset(Context::CLOSURE_INDEX)));
     // Load the function context (which is the incoming, outer context).
     ldr(dst, FieldMemOperand(dst, JSFunction::kContextOffset));
     for (int i = 1; i < context_chain_length; i++) {
@@ skipping 239 matching lines @@
 
 void CodePatcher::Emit(Address addr) {
   masm()->emit(reinterpret_cast<Instr>(addr));
 }
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM