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author | JF Bastien <jfb@google.com> | 2014-06-18 06:23:25 +0000 |
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committer | JF Bastien <jfb@google.com> | 2014-06-18 06:23:25 +0000 |
commit | 1d04a2324c4e86320b5452f5262782c569cd3315 (patch) | |
tree | b420a99cb06a321a7832af249a3a7d58493651bd /lib/IR | |
parent | 74287ec34c1443e462aba573c6e8f7d7f9defa35 (diff) | |
download | llvm-1d04a2324c4e86320b5452f5262782c569cd3315.tar.gz llvm-1d04a2324c4e86320b5452f5262782c569cd3315.tar.bz2 llvm-1d04a2324c4e86320b5452f5262782c569cd3315.tar.xz |
Random Number Generator (llvm)
Summary:
Provides an abstraction for a random number generator (RNG) that produces a stream of pseudo-random numbers.
The current implementation uses C++11 facilities and is therefore not cryptographically secure.
The RNG is salted with the text of the current command line invocation.
In addition, a user may specify a seed (reproducible builds).
In clang, the seed can be set via
-frandom-seed=X
In the back end, the seed can be set via
-rng-seed=X
This is the llvm part of the patch.
clang part: D3391
Reviewers: ahomescu, rinon, nicholas, jfb
Reviewed By: jfb
Subscribers: jfb, perl
Differential Revision: http://reviews.llvm.org/D3390
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211145 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/IR')
-rw-r--r-- | lib/IR/Module.cpp | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/lib/IR/Module.cpp b/lib/IR/Module.cpp index 6a5b386c19..0f73d44ce4 100644 --- a/lib/IR/Module.cpp +++ b/lib/IR/Module.cpp @@ -24,6 +24,8 @@ #include "llvm/IR/LLVMContext.h" #include "llvm/IR/LeakDetector.h" #include "llvm/Support/Dwarf.h" +#include "llvm/Support/Path.h" +#include "llvm/Support/RandomNumberGenerator.h" #include <algorithm> #include <cstdarg> #include <cstdlib> @@ -44,7 +46,7 @@ template class llvm::SymbolTableListTraits<GlobalAlias, Module>; // Module::Module(StringRef MID, LLVMContext &C) - : Context(C), Materializer(), ModuleID(MID), DL("") { + : Context(C), Materializer(), ModuleID(MID), RNG(nullptr), DL("") { ValSymTab = new ValueSymbolTable(); NamedMDSymTab = new StringMap<NamedMDNode *>(); Context.addModule(this); @@ -59,6 +61,7 @@ Module::~Module() { NamedMDList.clear(); delete ValSymTab; delete static_cast<StringMap<NamedMDNode *> *>(NamedMDSymTab); + delete RNG; } /// getNamedValue - Return the first global value in the module with @@ -355,6 +358,16 @@ const DataLayout *Module::getDataLayout() const { return &DL; } +// We want reproducible builds, but ModuleID may be a full path so we just use +// the filename to salt the RNG (although it is not guaranteed to be unique). +RandomNumberGenerator &Module::getRNG() const { + if (RNG == nullptr) { + StringRef Salt = sys::path::filename(ModuleID); + RNG = new RandomNumberGenerator(Salt); + } + return *RNG; +} + //===----------------------------------------------------------------------===// // Methods to control the materialization of GlobalValues in the Module. // |