diff options
Diffstat (limited to 'chrome/browser/metrics')
| -rw-r--r-- | chrome/browser/metrics/metrics_log.cc | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/chrome/browser/metrics/metrics_log.cc b/chrome/browser/metrics/metrics_log.cc index 2d00123..cef0a76 100644 --- a/chrome/browser/metrics/metrics_log.cc +++ b/chrome/browser/metrics/metrics_log.cc @@ -108,10 +108,14 @@ std::string MetricsLog::CreateHash(const std::string& value) { MD5Digest digest; MD5Final(&digest, &ctx); - unsigned char reverse[8]; // UMA only uses first 8 chars of hash. - DCHECK(arraysize(digest.a) >= arraysize(reverse)); - for (size_t i = 0; i < arraysize(reverse); ++i) - reverse[i] = digest.a[arraysize(reverse) - i - 1]; + uint64 reverse_uint64; + // UMA only uses first 8 chars of hash. We use the above uint64 instead + // of a unsigned char[8] so that we don't run into strict aliasing issues + // in the LOG statement below when trying to interpret reverse as a uint64. + unsigned char* reverse = reinterpret_cast<unsigned char *>(&reverse_uint64); + DCHECK(arraysize(digest.a) >= sizeof(reverse_uint64)); + for (size_t i = 0; i < sizeof(reverse_uint64); ++i) + reverse[i] = digest.a[sizeof(reverse_uint64) - i - 1]; // The following log is VERY helpful when folks add some named histogram into // the code, but forgot to update the descriptive list of histograms. When // that happens, all we get to see (server side) is a hash of the histogram @@ -119,7 +123,7 @@ std::string MetricsLog::CreateHash(const std::string& value) { // being hashed to a given MD5 value by just running the version of Chromium // in question with --enable-logging. LOG(INFO) << "Metrics: Hash numeric [" << value << "]=[" - << *reinterpret_cast<const uint64*>(&reverse[0]) << "]"; + << reverse_uint64 << "]"; return std::string(reinterpret_cast<char*>(digest.a), arraysize(digest.a)); } |