[debug] Untangle DebugInfo from break point support

src/builtins/ia32/builtins-ia32.cc

Index: src/builtins/ia32/builtins-ia32.cc
diff --git a/src/builtins/ia32/builtins-ia32.cc b/src/builtins/ia32/builtins-ia32.cc
index bcffedfef2ba51010fbfff161b626e0b1a82a4a9..22d88388869b08fa29e10ad162d63974f7942587 100644
--- a/src/builtins/ia32/builtins-ia32.cc
+++ b/src/builtins/ia32/builtins-ia32.cc
@@ -710,12 +710,12 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
 
   // Get the bytecode array from the function object (or from the DebugInfo if
   // it is present) and load it into kInterpreterBytecodeArrayRegister.
+  Label maybe_load_debug_bytecode_array, bytecode_array_loaded;
   __ mov(eax, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
-  Label load_debug_bytecode_array, bytecode_array_loaded;
-  __ JumpIfNotSmi(FieldOperand(eax, SharedFunctionInfo::kDebugInfoOffset),
-                  &load_debug_bytecode_array);
   __ mov(kInterpreterBytecodeArrayRegister,
          FieldOperand(eax, SharedFunctionInfo::kFunctionDataOffset));
+  __ JumpIfNotSmi(FieldOperand(eax, SharedFunctionInfo::kDebugInfoOffset),
+                  &maybe_load_debug_bytecode_array);
   __ bind(&bytecode_array_loaded);
 
   // Check whether we should continue to use the interpreter.
@@ -802,12 +802,17 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
   LeaveInterpreterFrame(masm, ebx, ecx);
   __ ret(0);
 
-  // Load debug copy of the bytecode array.
-  __ bind(&load_debug_bytecode_array);
-  Register debug_info = kInterpreterBytecodeArrayRegister;
-  __ mov(debug_info, FieldOperand(eax, SharedFunctionInfo::kDebugInfoOffset));
+  // Load debug copy of the bytecode array if it exists.
+  // kInterpreterBytecodeArrayRegister is already loaded with
+  // SharedFunctionInfo::kFunctionDataOffset.
+  __ bind(&maybe_load_debug_bytecode_array);
+  __ mov(ecx, FieldOperand(eax, SharedFunctionInfo::kDebugInfoOffset));
+  __ mov(ebx, FieldOperand(ecx, DebugInfo::kFlagsOffset));
+  __ SmiUntag(ebx);
+  __ test(ebx, Immediate(DebugInfo::kHasBreakInfo));
+  __ j(zero, &bytecode_array_loaded);
   __ mov(kInterpreterBytecodeArrayRegister,
-         FieldOperand(debug_info, DebugInfo::kDebugBytecodeArrayIndex));
+         FieldOperand(ecx, DebugInfo::kDebugBytecodeArrayOffset));
   __ jmp(&bytecode_array_loaded);
 
   // If the shared code is no longer this entry trampoline, then the underlying