Make --trace-deopt --code-comments print the Lithium instruction that caused deoptimization.

src/deoptimizer.cc

 // Copyright 2011 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 329 matching lines @@
     function->PrintName();
     PrintF(" at ast id #%u, address 0x%" V8PRIxPTR ", frame size %d\n",
            bailout_id,
            reinterpret_cast<intptr_t>(from),
            fp_to_sp_delta - (2 * kPointerSize));
   }
   // Find the optimized code.
   if (type == EAGER) {
     ASSERT(from == NULL);
     optimized_code_ = function_->code();
+    if (FLAG_trace_deopt && FLAG_code_comments) {
+      // Print instruction associated with this bailout.
+      const char* last_comment = NULL;
+      int mask = RelocInfo::ModeMask(RelocInfo::COMMENT)
+          | RelocInfo::ModeMask(RelocInfo::RUNTIME_ENTRY);
+      for (RelocIterator it(optimized_code_, mask); !it.done(); it.next()) {
+        RelocInfo* info = it.rinfo();
+        if (info->rmode() == RelocInfo::COMMENT) {
+          last_comment = reinterpret_cast<const char*>(info->data());
+        }
+        if (info->rmode() == RelocInfo::RUNTIME_ENTRY) {
+          unsigned id = Deoptimizer::GetDeoptimizationId(
+              info->target_address(), Deoptimizer::EAGER);
+          if (id == bailout_id && last_comment != NULL) {
+            PrintF("            %s\n", last_comment);
+            break;
+          }
+        }
+      }
+    }
   } else if (type == LAZY) {
     optimized_code_ = FindDeoptimizingCodeFromAddress(from);
     ASSERT(optimized_code_ != NULL);
   } else if (type == OSR) {
     // The function has already been optimized and we're transitioning
     // from the unoptimized shared version to the optimized one in the
     // function. The return address (from) points to unoptimized code.
     optimized_code_ = function_->code();
     ASSERT(optimized_code_->kind() == Code::OPTIMIZED_FUNCTION);
     ASSERT(!optimized_code_->contains(from));
@@ skipping 1120 matching lines @@
 
 void DeoptimizedFrameInfo::Iterate(ObjectVisitor* v) {
   v->VisitPointer(BitCast<Object**>(&function_));
   v->VisitPointers(parameters_, parameters_ + parameters_count_);
   v->VisitPointers(expression_stack_, expression_stack_ + expression_count_);
 }
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 } }  // namespace v8::internal