Collect information about failing histogram factory calls.

base/metrics/statistics_recorder.cc

 // Copyright (c) 2012 The Chromium 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 "base/metrics/statistics_recorder.h"
 
 #include "base/at_exit.h"
+#include "base/debug/alias.h"
 #include "base/debug/leak_annotations.h"
 #include "base/json/string_escape.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/metrics_hashes.h"
 #include "base/stl_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/synchronization/lock.h"
 #include "base/values.h"
@@ skipping 107 matching lines @@
             histogram->SetFlags(HistogramBase::kCallbackExists);
           else
             histogram->ClearFlags(HistogramBase::kCallbackExists);
         }
         histogram_to_return = histogram;
       } else if (histogram == it->second) {
         // The histogram was registered before.
         histogram_to_return = histogram;
       } else {
         // We already have one histogram with this name.
-        DCHECK_EQ(histogram->histogram_name(),
-                  it->second->histogram_name()) << "hash collision";
+        CHECK_EQ(histogram->histogram_name(),
+                 it->second->histogram_name()) << "hash collision";
         histogram_to_return = it->second;
         histogram_to_delete = histogram;
       }
+      base::debug::Alias(&it);
+      base::debug::Alias(&name);
+      base::debug::Alias(&name_hash);
     }
   }
+  base::debug::Alias(&histogram);
   delete histogram_to_delete;
   return histogram_to_return;
 }
 
 // static
 const BucketRanges* StatisticsRecorder::RegisterOrDeleteDuplicateRanges(
     const BucketRanges* ranges) {
   DCHECK(ranges->HasValidChecksum());
   scoped_ptr<const BucketRanges> ranges_deleter;
 
@@ skipping 129 matching lines @@
 }
 
 // static
 HistogramBase* StatisticsRecorder::FindHistogram(base::StringPiece name) {
   if (lock_ == NULL)
     return NULL;
   base::AutoLock auto_lock(*lock_);
   if (histograms_ == NULL)
     return NULL;
 
-  HistogramMap::iterator it = histograms_->find(HashMetricName(name));
+  const uint64_t lookup_hash = HashMetricName(name);
+  HistogramMap::iterator it = histograms_->find(lookup_hash);
   if (histograms_->end() == it)
     return NULL;
-  DCHECK_EQ(name, it->second->histogram_name()) << "hash collision";
+
+  const uint64_t existing_hash = it->first;
+  const char* existing_name = it->second->histogram_name().c_str();
+  HistogramMap* histograms = histograms_;
+  CHECK_EQ(name, it->second->histogram_name()) << "hash collision";
+  base::debug::Alias(&lookup_hash);
+  base::debug::Alias(&existing_hash);
+  base::debug::Alias(&name);
+  base::debug::Alias(&existing_name);
+  base::debug::Alias(&it);
+  base::debug::Alias(&histograms);
+
   return it->second;
 }
 
 // static
 StatisticsRecorder::HistogramIterator StatisticsRecorder::begin(
     bool include_persistent) {
   return HistogramIterator(histograms_->begin(), include_persistent);
 }
 
 // static
@@ skipping 152 matching lines @@
 // static
 StatisticsRecorder::HistogramMap* StatisticsRecorder::histograms_ = NULL;
 // static
 StatisticsRecorder::CallbackMap* StatisticsRecorder::callbacks_ = NULL;
 // static
 StatisticsRecorder::RangesMap* StatisticsRecorder::ranges_ = NULL;
 // static
 base::Lock* StatisticsRecorder::lock_ = NULL;
 
 }  // namespace base