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| author | dim <dim@FreeBSD.org> | 2014-11-24 17:02:24 +0000 |
|---|---|---|
| committer | dim <dim@FreeBSD.org> | 2014-11-24 17:02:24 +0000 |
| commit | 2c8643c6396b0a3db33430cf9380e70bbb9efce0 (patch) | |
| tree | 4df130b28021d86e13bf4565ef58c1c5a5e093b4 /contrib/llvm/lib/Support/RandomNumberGenerator.cpp | |
| parent | 678318cd20f7db4e6c6b85d83fe00fa327b04fca (diff) | |
| parent | e27feadae0885aa074df58ebfda2e7a7f7a7d590 (diff) | |
| download | FreeBSD-src-2c8643c6396b0a3db33430cf9380e70bbb9efce0.zip FreeBSD-src-2c8643c6396b0a3db33430cf9380e70bbb9efce0.tar.gz | |
Merge llvm 3.5.0 release from ^/vendor/llvm/dist, resolve conflicts, and
preserve our customizations, where necessary.
Diffstat (limited to 'contrib/llvm/lib/Support/RandomNumberGenerator.cpp')
| -rw-r--r-- | contrib/llvm/lib/Support/RandomNumberGenerator.cpp | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Support/RandomNumberGenerator.cpp b/contrib/llvm/lib/Support/RandomNumberGenerator.cpp new file mode 100644 index 0000000..c50e7cb --- /dev/null +++ b/contrib/llvm/lib/Support/RandomNumberGenerator.cpp @@ -0,0 +1,61 @@ +//===-- RandomNumberGenerator.cpp - Implement RNG class -------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements random number generation (RNG). +// The current implementation is NOT cryptographically secure as it uses +// the C++11 <random> facilities. +// +//===----------------------------------------------------------------------===// + +#define DEBUG_TYPE "rng" +#include "llvm/Support/RandomNumberGenerator.h" +#include "llvm/Support/CommandLine.h" +#include "llvm/Support/Debug.h" + +using namespace llvm; + +// Tracking BUG: 19665 +// http://llvm.org/bugs/show_bug.cgi?id=19665 +// +// Do not change to cl::opt<uint64_t> since this silently breaks argument parsing. +static cl::opt<unsigned long long> +Seed("rng-seed", cl::value_desc("seed"), + cl::desc("Seed for the random number generator"), cl::init(0)); + +RandomNumberGenerator::RandomNumberGenerator(StringRef Salt) { + DEBUG( + if (Seed == 0) + errs() << "Warning! Using unseeded random number generator.\n" + ); + + // Combine seed and salt using std::seed_seq. + // Entropy: Seed-low, Seed-high, Salt... + std::vector<uint32_t> Data; + Data.reserve(2 + Salt.size()/4 + 1); + Data.push_back(Seed); + Data.push_back(Seed >> 32); + + uint32_t Pack = 0; + for (size_t I = 0; I < Salt.size(); ++I) { + Pack <<= 8; + Pack += Salt[I]; + + if (I%4 == 3) + Data.push_back(Pack); + } + Data.push_back(Pack); + + std::seed_seq SeedSeq(Data.begin(), Data.end()); + Generator.seed(SeedSeq); +} + +uint64_t RandomNumberGenerator::next(uint64_t Max) { + std::uniform_int_distribution<uint64_t> distribution(0, Max - 1); + return distribution(Generator); +} |
