Fix issues with Arm's use of embedded constant pools

src/arm/builtins-arm.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_ARM
 
 #include "src/codegen.h"
 #include "src/debug.h"
@@ skipping 1148 matching lines @@
   __ b(ne, &skip);
   __ Ret();
 
   __ bind(&skip);
 
   // Load deoptimization data from the code object.
   // <deopt_data> = <code>[#deoptimization_data_offset]
   __ ldr(r1, FieldMemOperand(r0, Code::kDeoptimizationDataOffset));
 
   { ConstantPoolUnavailableScope constant_pool_unavailable(masm);
+    __ add(r0, r0, Operand(Code::kHeaderSize - kHeapObjectTag));  // Code start
+
     if (FLAG_enable_embedded_constant_pool) {
       __ LoadConstantPoolPointerRegisterFromCodeTargetAddress(r0);
     }
 
     // Load the OSR entrypoint offset from the deoptimization data.
     // <osr_offset> = <deopt_data>[#header_size + #osr_pc_offset]
     __ ldr(r1, FieldMemOperand(r1, FixedArray::OffsetOfElementAt(
         DeoptimizationInputData::kOsrPcOffsetIndex)));
 
-    // Compute the target address = code_obj + header_size + osr_offset
-    // <entry_addr> = <code_obj> + #header_size + <osr_offset>
-    __ add(r0, r0, Operand::SmiUntag(r1));
-    __ add(lr, r0, Operand(Code::kHeaderSize - kHeapObjectTag));
+    // Compute the target address = code start + osr_offset
+    __ add(lr, r0, Operand::SmiUntag(r1));
 
     // And "return" to the OSR entry point of the function.
     __ Ret();
   }
 }
 
 
 void Builtins::Generate_OsrAfterStackCheck(MacroAssembler* masm) {
   // We check the stack limit as indicator that recompilation might be done.
   Label ok;
@@ skipping 618 matching lines @@
   }
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM