ensure we have warnings set everywhere and fix some

BUILD.bazel

@@ -1,5 +1,22 @@
 licenses(["notice"])
 
+COPTS = [
+    "-pedantic",
+    "-pedantic-errors",
+    "-std=c++11",
+    "-Wall",
+    "-Wconversion",
+    "-Wextra",
+    "-Wshadow",
+    #    "-Wshorten-64-to-32",
+    "-Wfloat-equal",
+    "-fstrict-aliasing",
+    ## assert() are used a lot in tests upstream, which may be optimised out leading to
+    ## unused-variable warning.
+    "-Wno-unused-variable",
+    "-Werror=old-style-cast",
+]
+
 config_setting(
     name = "qnx",
     constraint_values = ["@platforms//os:qnx"],
@@ -47,7 +64,7 @@ cc_library(
     ],
     copts = select({
         ":windows": [],
-        "//conditions:default": ["-Werror=old-style-cast"],
+        "//conditions:default": COPTS,
     }),
     defines = [
         "BENCHMARK_STATIC_DEFINE",

CMakeLists.txt

@@ -190,6 +190,7 @@ else()
   add_cxx_compiler_flag(-Wshadow)
   add_cxx_compiler_flag(-Wfloat-equal)
   add_cxx_compiler_flag(-Wold-style-cast)
+  add_cxx_compiler_flag(-Wconversion)
   if(BENCHMARK_ENABLE_WERROR)
       add_cxx_compiler_flag(-Werror)
   endif()

include/benchmark/benchmark.h

@@ -1304,7 +1304,7 @@ class BENCHMARK_EXPORT Benchmark {
  public:
   const char* GetName() const;
   int ArgsCnt() const;
-  const char* GetArgName(int arg) const;
+  const char* GetArgName(size_t arg) const;
 
  private:
   friend class BenchmarkFamilies;

src/benchmark.cc

@@ -407,7 +407,8 @@ void RunBenchmarks(const std::vector<BenchmarkInstance>& benchmarks,
       benchmarks_with_threads += (benchmark.threads() > 1);
       runners.emplace_back(benchmark, &perfcounters, reports_for_family);
       int num_repeats_of_this_instance = runners.back().GetNumRepeats();
-      num_repetitions_total += num_repeats_of_this_instance;
+      num_repetitions_total +=
+          static_cast<size_t>(num_repeats_of_this_instance);
       if (reports_for_family)
         reports_for_family->num_runs_total += num_repeats_of_this_instance;
     }

src/benchmark_register.cc

@@ -480,9 +480,8 @@ int Benchmark::ArgsCnt() const {
   return static_cast<int>(args_.front().size());
 }
 
-const char* Benchmark::GetArgName(int arg) const {
-  BM_CHECK_GE(arg, 0);
-  BM_CHECK_LT(arg, static_cast<int>(arg_names_.size()));
+const char* Benchmark::GetArgName(size_t arg) const {
+  BM_CHECK_LT(arg, arg_names_.size());
   return arg_names_[arg].c_str();
 }
 

src/benchmark_runner.cc

@@ -235,7 +235,7 @@ BenchmarkRunner::BenchmarkRunner(
       has_explicit_iteration_count(b.iterations() != 0 ||
                                    parsed_benchtime_flag.tag ==
                                        BenchTimeType::ITERS),
-      pool(b.threads() - 1),
+      pool(static_cast<size_t>(b.threads() - 1)),
       iters(has_explicit_iteration_count
                 ? ComputeIters(b_, parsed_benchtime_flag)
                 : 1),

src/cycleclock.h

@@ -82,7 +82,7 @@ inline BENCHMARK_ALWAYS_INLINE int64_t Now() {
 #elif defined(__x86_64__) || defined(__amd64__)
   uint64_t low, high;
   __asm__ volatile("rdtsc" : "=a"(low), "=d"(high));
-  return (high << 32) | low;
+  return static_cast<int64_t>((high << 32) | low);
 #elif defined(__powerpc__) || defined(__ppc__)
   // This returns a time-base, which is not always precisely a cycle-count.
 #if defined(__powerpc64__) || defined(__ppc64__)

src/statistics.cc

@@ -97,7 +97,7 @@ std::vector<BenchmarkReporter::Run> ComputeStats(
   auto error_count = std::count_if(reports.begin(), reports.end(),
                                    [](Run const& run) { return run.skipped; });
 
-  if (reports.size() - error_count < 2) {
+  if (reports.size() - static_cast<size_t>(error_count) < 2) {
     // We don't report aggregated data if there was a single run.
     return results;
   }
@@ -179,7 +179,7 @@ std::vector<BenchmarkReporter::Run> ComputeStats(
     // Similarly, if there are N repetitions with 1 iterations each,
     // an aggregate will be computed over N measurements, not 1.
     // Thus it is best to simply use the count of separate reports.
-    data.iterations = reports.size();
+    data.iterations = static_cast<IterationCount>(reports.size());
 
     data.real_accumulated_time = Stat.compute_(real_accumulated_time_stat);
     data.cpu_accumulated_time = Stat.compute_(cpu_accumulated_time_stat);

src/string_util.cc

@@ -56,7 +56,7 @@ void ToExponentAndMantissa(double val, int precision, double one_k,
       scaled /= one_k;
       if (scaled <= big_threshold) {
         mantissa_stream << scaled;
-        *exponent = i + 1;
+        *exponent = static_cast<int64_t>(i + 1);
         *mantissa = mantissa_stream.str();
         return;
       }

src/sysinfo.cc

@@ -120,7 +120,7 @@ struct ValueUnion {
 
   explicit ValueUnion(std::size_t buff_size)
       : size(sizeof(DataT) + buff_size),
-        buff(::new (std::malloc(size)) DataT(), &std::free) {}
+        buff(::new(std::malloc(size)) DataT(), &std::free) {}
 
   ValueUnion(ValueUnion&& other) = default;
 
@@ -837,7 +837,7 @@ std::vector<double> GetLoadAvg() {
     !(defined(__ANDROID__) && __ANDROID_API__ < 29)
   static constexpr int kMaxSamples = 3;
   std::vector<double> res(kMaxSamples, 0.0);
-  const int nelem = getloadavg(res.data(), kMaxSamples);
+  const size_t nelem = static_cast<size_t>(getloadavg(res.data(), kMaxSamples));
   if (nelem < 1) {
     res.clear();
   } else {

src/timers.cc

@@ -245,9 +245,9 @@ std::string LocalDateTimeString() {
       tz_offset_sign = '-';
     }
 
-    tz_len =
+    tz_len = static_cast<size_t>(
         ::snprintf(tz_offset, sizeof(tz_offset), "%c%02li:%02li",
-                   tz_offset_sign, offset_minutes / 100, offset_minutes % 100);
+                   tz_offset_sign, offset_minutes / 100, offset_minutes % 100));
     BM_CHECK(tz_len == kTzOffsetLen);
     ((void)tz_len);  // Prevent unused variable warning in optimized build.
   } else {

test/BUILD

@@ -21,6 +21,7 @@ TEST_COPTS = [
     ## assert() are used a lot in tests upstream, which may be optimised out leading to
     ## unused-variable warning.
     "-Wno-unused-variable",
+    "-Werror=old-style-cast",
 ]
 
 # Some of the issues with DoNotOptimize only occur when optimization is enabled