From ce7d3124bee8cd4c022a5084461bdf64b55d613c Mon Sep 17 00:00:00 2001 From: Christopher Dykes Date: Mon, 19 Dec 2016 19:32:26 -0800 Subject: [PATCH] Enable -Wunreachable-code Summary: Because it finds dead code. This also removes the dead code found. Reviewed By: yfeldblum Differential Revision: D4342893 fbshipit-source-id: e500734ff5927320b2356106d10016e298d67393 --- folly/Benchmark.cpp | 117 ------------------ folly/dynamic.cpp | 7 +- folly/experimental/DynamicParser.cpp | 1 - .../exception_tracer/ExceptionTracerLib.cpp | 10 +- folly/fibers/test/FibersTest.cpp | 2 +- 5 files changed, 14 insertions(+), 123 deletions(-) diff --git a/folly/Benchmark.cpp b/folly/Benchmark.cpp index ccae0344..2ab417f0 100644 --- a/folly/Benchmark.cpp +++ b/folly/Benchmark.cpp @@ -105,75 +105,6 @@ void detail::addBenchmarkImpl(const char* file, const char* name, benchmarks().emplace_back(file, name, std::move(fun)); } -/** - * Given a point, gives density at that point as a number 0.0 < x <= - * 1.0. The result is 1.0 if all samples are equal to where, and - * decreases near 0 if all points are far away from it. The density is - * computed with the help of a radial basis function. - */ -static double density(const double * begin, const double *const end, - const double where, const double bandwidth) { - assert(begin < end); - assert(bandwidth > 0.0); - double sum = 0.0; - FOR_EACH_RANGE (i, begin, end) { - auto d = (*i - where) / bandwidth; - sum += exp(- d * d); - } - return sum / (end - begin); -} - -/** - * Computes mean and variance for a bunch of data points. Note that - * mean is currently not being used. - */ -static pair -meanVariance(const double * begin, const double *const end) { - assert(begin < end); - double sum = 0.0, sum2 = 0.0; - FOR_EACH_RANGE (i, begin, end) { - sum += *i; - sum2 += *i * *i; - } - auto const n = end - begin; - return make_pair(sum / n, sqrt((sum2 - sum * sum / n) / n)); -} - -/** - * Computes the mode of a sample set through brute force. Assumes - * input is sorted. - */ -static double mode(const double * begin, const double *const end) { - assert(begin < end); - // Lower bound and upper bound for result and their respective - // densities. - auto - result = 0.0, - bestDensity = 0.0; - - // Get the variance so we pass it down to density() - auto const sigma = meanVariance(begin, end).second; - if (!sigma) { - // No variance means constant signal - return *begin; - } - - FOR_EACH_RANGE (i, begin, end) { - assert(i == begin || *i >= i[-1]); - auto candidate = density(begin, end, *i, sigma * sqrt(2.0)); - if (candidate > bestDensity) { - // Found a new best - bestDensity = candidate; - result = *i; - } else { - // Density is decreasing... we could break here if we definitely - // knew this is unimodal. - } - } - - return result; -} - /** * Given a bunch of benchmark samples, estimate the actual run time. */ @@ -182,55 +113,7 @@ static double estimateTime(double * begin, double * end) { // Current state of the art: get the minimum. After some // experimentation, it seems taking the minimum is the best. - return *min_element(begin, end); - - // What follows after estimates the time as the mode of the - // distribution. - - // Select the awesomest (i.e. most frequent) result. We do this by - // sorting and then computing the longest run length. - sort(begin, end); - - // Eliminate outliers. A time much larger than the minimum time is - // considered an outlier. - while (end[-1] > 2.0 * *begin) { - --end; - if (begin == end) { - LOG(INFO) << *begin; - } - assert(begin < end); - } - - double result = 0; - - /* Code used just for comparison purposes */ { - unsigned bestFrequency = 0; - unsigned candidateFrequency = 1; - double candidateValue = *begin; - for (auto current = begin + 1; ; ++current) { - if (current == end || *current != candidateValue) { - // Done with the current run, see if it was best - if (candidateFrequency > bestFrequency) { - bestFrequency = candidateFrequency; - result = candidateValue; - } - if (current == end) { - break; - } - // Start a new run - candidateValue = *current; - candidateFrequency = 1; - } else { - // Cool, inside a run, increase the frequency - ++candidateFrequency; - } - } - } - - result = mode(begin, end); - - return result; } static double runBenchmarkGetNSPerIteration(const BenchmarkFun& fun, diff --git a/folly/dynamic.cpp b/folly/dynamic.cpp index 5e656c5e..e9a37a99 100644 --- a/folly/dynamic.cpp +++ b/folly/dynamic.cpp @@ -14,8 +14,10 @@ * limitations under the License. */ -#include #include + +#include +#include #include namespace folly { @@ -277,9 +279,8 @@ std::size_t dynamic::hash() const { const auto& str = getString(); return ::folly::hash::fnv32_buf(str.data(), str.size()); } - default: - CHECK(0); abort(); } + assume_unreachable(); } char const* dynamic::typeName(Type t) { diff --git a/folly/experimental/DynamicParser.cpp b/folly/experimental/DynamicParser.cpp index 18dd25fd..734013c9 100644 --- a/folly/experimental/DynamicParser.cpp +++ b/folly/experimental/DynamicParser.cpp @@ -96,7 +96,6 @@ void DynamicParser::reportError( break; // Continue parsing case OnError::THROW: stack_.throwErrors(); // Package releaseErrors() into an exception. - LOG(FATAL) << "Not reached"; // silence lint false positive default: LOG(FATAL) << "Bad onError_: " << static_cast(onError_); } diff --git a/folly/experimental/exception_tracer/ExceptionTracerLib.cpp b/folly/experimental/exception_tracer/ExceptionTracerLib.cpp index 2ba97b78..4a10d41c 100644 --- a/folly/experimental/exception_tracer/ExceptionTracerLib.cpp +++ b/folly/experimental/exception_tracer/ExceptionTracerLib.cpp @@ -34,7 +34,6 @@ void __cxa_throw( void (*destructor)(void*)) __attribute__((__noreturn__)); void* __cxa_begin_catch(void* excObj) throw(); void __cxa_rethrow(void) __attribute__((__noreturn__)); -void __cxa_rethrow(void); void __cxa_end_catch(void); } @@ -88,6 +87,15 @@ DECLARE_CALLBACK(RethrowException); } // exception_tracer } // folly +// Clang is smart enough to understand that the symbols we're loading +// are [[noreturn]], but GCC is not. In order to be able to build with +// -Wunreachable-code enable for Clang, these __builtin_unreachable() +// calls need to go away. Everything else is messy though, so just +// #define it to an empty macro under Clang and be done with it. +#ifdef __clang__ +# define __builtin_unreachable() +#endif + namespace __cxxabiv1 { void __cxa_throw(void* thrownException, diff --git a/folly/fibers/test/FibersTest.cpp b/folly/fibers/test/FibersTest.cpp index d096839a..7816f982 100644 --- a/folly/fibers/test/FibersTest.cpp +++ b/folly/fibers/test/FibersTest.cpp @@ -1964,7 +1964,7 @@ TEST(FiberManager, ABD_DispatcherDestroyedBeforeCallingCommit) { dispatchJobs(executor, jobs, results); throw std::runtime_error( "Unexpected exception in user code before commit called"); - atomicBatchDispatcher.commit(); + // atomicBatchDispatcher.commit(); } catch (...) { /* User code handles the exception and does not exit process */ } -- 2.34.1