Migrated to use Module::createRNG and removed anonymous namespace where static functions were appropriate

include/DuplicateBB.h

@@ -17,6 +17,11 @@
 #include "llvm/Pass.h"
 
 #include <map>
+#include <memory>
+
+namespace llvm {
+class RandomNumberGenerator;
+} // namespace llvm
 
 //------------------------------------------------------------------------------
 // New PM interface
@@ -51,6 +56,8 @@ struct DuplicateBB : public llvm::PassInfoMixin<DuplicateBB> {
   // decorated with the optnone LLVM attribute. Note that clang -O0 decorates
   // all functions with optnone.
   static bool isRequired() { return true; }
+
+  std::unique_ptr<llvm::RandomNumberGenerator> pRNG;
 };
 
 #endif

lib/ConvertFCmpEq.cpp

@@ -47,9 +47,7 @@
 using namespace llvm;
 
 // Unnamed namespace for private functions
-namespace {
-
-FCmpInst *convertFCmpEqInstruction(FCmpInst *FCmp) noexcept {
+static FCmpInst *convertFCmpEqInstruction(FCmpInst *FCmp) noexcept {
   assert(FCmp && "The given fcmp instruction is null");
 
   if (!FCmp->isEquality()) {
@@ -115,8 +113,6 @@ FCmpInst *convertFCmpEqInstruction(FCmpInst *FCmp) noexcept {
   return FCmp;
 }
 
-} // namespace
-
 static constexpr char PassArg[] = "convert-fcmp-eq";
 static constexpr char PassName[] =
     "Convert floating-point equality comparisons";

lib/DuplicateBB.cpp

@@ -84,6 +84,7 @@
 #include "llvm/Passes/PassPlugin.h"
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
 #include "llvm/Transforms/Utils/Cloning.h"
+#include "llvm/Support/RandomNumberGenerator.h"
 
 #include <random>
 
@@ -100,15 +101,6 @@ DuplicateBB::BBToSingleRIVMap
 DuplicateBB::findBBsToDuplicate(Function &F, const RIV::Result &RIVResult) {
   BBToSingleRIVMap BlocksToDuplicate;
 
-  // Get a random number generator. This will be used to choose a context
-  // value for the injected `if-then-else` construct.
-  // FIXME Switch to 'F.getParent()->createRNG("DuplicateBB")' once possible.
-  // This patch implements the necessary API:
-  //    * https://reviews.llvm.org/rG73713f3e5ef2ecf1e5afafa89f76ab89cc06b18e
-  // It should be available in LLVM 11.
-  std::random_device RD;
-  std::mt19937_64 RNG(RD());
-
   for (BasicBlock &BB : F) {
     // Basic blocks which are landing pads are used for handling exceptions.
     // That's out of scope of this pass.
@@ -129,7 +121,7 @@ DuplicateBB::findBBsToDuplicate(Function &F, const RIV::Result &RIVResult) {
     // Get a random context value from the RIV set
     auto Iter = ReachableValues.begin();
     std::uniform_int_distribution<> Dist(0, ReachableValuesCount - 1);
-    std::advance(Iter, Dist(RNG));
+    std::advance(Iter, Dist(*pRNG));
 
     if (dyn_cast<GlobalValue>(*Iter)) {
       LLVM_DEBUG(errs() << "Random context value is a global variable. "
@@ -243,6 +235,9 @@ void DuplicateBB::cloneBB(BasicBlock &BB, Value *ContextValue,
 
 PreservedAnalyses DuplicateBB::run(llvm::Function &F,
                                    llvm::FunctionAnalysisManager &FAM) {
+  if (!pRNG)
+    pRNG = F.getParent()->createRNG("duplicate-bb");
+
   BBToSingleRIVMap Targets = findBBsToDuplicate(F, FAM.getResult<RIV>(F));
 
   // This map is used to keep track of the new bindings. Otherwise, the

lib/FindFCmpEq.cpp

@@ -45,9 +45,6 @@
 
 using namespace llvm;
 
-// Unnamed namespace for internal functions
-namespace {
-
 static void
 printFCmpEqInstructions(raw_ostream &OS, Function &Func,
                         const FindFCmpEq::Result &FCmpEqInsts) noexcept {
@@ -68,8 +65,6 @@ printFCmpEqInstructions(raw_ostream &OS, Function &Func,
   }
 }
 
-} // namespace
-
 static constexpr char PassArg[] = "find-fcmp-eq";
 static constexpr char PassName[] =
     "Floating-point equality comparisons locator";