mirror of
https://github.com/RPCSX/llvm.git
synced 2024-12-15 16:09:02 +00:00
544f63e84a
This patch removes the RNG from Module. Passes should instead create a new RNG for their use as needed. Patch by Stephen Crane @rinon. Differential revision: http://reviews.llvm.org/D4377 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224444 91177308-0d34-0410-b5e6-96231b3b80d8
56 lines
1.8 KiB
C++
56 lines
1.8 KiB
C++
//===-- 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 deterministic 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/CommandLine.h"
|
|
#include "llvm/Support/Debug.h"
|
|
#include "llvm/Support/RandomNumberGenerator.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)
|
|
dbgs() << "Warning! Using unseeded random number generator.\n"
|
|
);
|
|
|
|
// Combine seed and salts using std::seed_seq.
|
|
// Data: Seed-low, Seed-high, Salt
|
|
// Note: std::seed_seq can only store 32-bit values, even though we
|
|
// are using a 64-bit RNG. This isn't a problem since the Mersenne
|
|
// twister constructor copies these correctly into its initial state.
|
|
std::vector<uint32_t> Data;
|
|
Data.reserve(2 + Salt.size());
|
|
Data.push_back(Seed);
|
|
Data.push_back(Seed >> 32);
|
|
|
|
std::copy(Salt.begin(), Salt.end(), Data.end());
|
|
|
|
std::seed_seq SeedSeq(Data.begin(), Data.end());
|
|
Generator.seed(SeedSeq);
|
|
}
|
|
|
|
uint_fast64_t RandomNumberGenerator::operator()() {
|
|
return Generator();
|
|
}
|