Random Number Generator (llvm)

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

URL: http://reviews.llvm.org/D3390
Author: yln

I'm landing this for the second time, it broke Windows bots the first time around.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211705 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 0 deletions

diff --git a/include/llvm/IR/Module.h b/include/llvm/IR/Module.h
index 7230df9f79..77e5d21e29 100644
--- a/include/llvm/IR/Module.h
+++ b/include/llvm/IR/Module.h
@@ -29,6 +29,7 @@ namespace llvm {
 class FunctionType;
 class GVMaterializer;
 class LLVMContext;
+class RandomNumberGenerator;
 class StructType;
 template<typename T> struct DenseMapInfo;
 template<typename KeyT, typename ValueT, typename KeyInfoT> class DenseMap;
@@ -201,6 +202,8 @@ private:
   std::string ModuleID;           ///< Human readable identifier for the module
   std::string TargetTriple;       ///< Platform target triple Module compiled on
   void *NamedMDSymTab;            ///< NamedMDNode names.
+  // Allow lazy initialization in const method.
+  mutable RandomNumberGenerator *RNG; ///< The random number generator for this module.
 
   // We need to keep the string because the C API expects us to own the string
   // representation.
@@ -249,6 +252,11 @@ public:
   /// @returns a string containing the module-scope inline assembly blocks.
   const std::string &getModuleInlineAsm() const { return GlobalScopeAsm; }
 
+  /// Get the RandomNumberGenerator for this module. The RNG can be
+  /// seeded via -rng-seed=<uint64> and is salted with the ModuleID.
+  /// The returned RNG should not be shared across threads.
+  RandomNumberGenerator &getRNG() const;
+
 /// @}
 /// @name Module Level Mutators
 /// @{