Fix preparing log file name.

src/log.cc

 // Copyright 2011 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/log.h"
 
 #include <cstdarg>
 #include <sstream>
 
 #include "src/v8.h"
@@ skipping 1749 matching lines @@
 
 
 static void AddIsolateIdIfNeeded(std::ostream& os,  // NOLINT
                                  Isolate* isolate) {
   if (FLAG_logfile_per_isolate) os << "isolate-" << isolate << "-";
 }
 
 
 static void PrepareLogFileName(std::ostream& os,  // NOLINT
                                Isolate* isolate, const char* file_name) {
-  AddIsolateIdIfNeeded(os, isolate);
+  int dir_separator_count = 0;
   for (const char* p = file_name; *p; p++) {
+    if (base::OS::isDirectorySeparator(*p)) dir_separator_count++;
+  }
+
+  for (const char* p = file_name; *p; p++) {
+    if (dir_separator_count == 0) {
+      AddIsolateIdIfNeeded(os, isolate);
+      dir_separator_count--;
+    }
     if (*p == '%') {
       p++;
       switch (*p) {
         case '\0':
           // If there's a % at the end of the string we back up
           // one character so we can escape the loop properly.
           p--;
           break;
         case 'p':
           os << base::OS::GetCurrentProcessId();
           break;
         case 't':
           // %t expands to the current time in milliseconds.
           os << static_cast<int64_t>(base::OS::TimeCurrentMillis());
           break;
         case '%':
           // %% expands (contracts really) to %.
           os << '%';
           break;
         default:
           // All other %'s expand to themselves.
           os << '%' << *p;
           break;
       }
     } else {
+      if (base::OS::isDirectorySeparator(*p)) dir_separator_count--;
       os << *p;
     }
   }
 }
 
 
 bool Logger::SetUp(Isolate* isolate) {
   // Tests and EnsureInitialize() can call this twice in a row. It's harmless.
   if (is_initialized_) return true;
   is_initialized_ = true;
@@ skipping 101 matching lines @@
   if (jit_logger_) {
     removeCodeEventListener(jit_logger_);
     delete jit_logger_;
     jit_logger_ = NULL;
   }
 
   return log_->Close();
 }
 
 } }  // namespace v8::internal