Use separate random number generator for each randomization pass

src/IceELFObjectWriter.cpp

Index: src/IceELFObjectWriter.cpp
diff --git a/src/IceELFObjectWriter.cpp b/src/IceELFObjectWriter.cpp
index f32a2b6671bb9b2857cfa77387f7f68c6edbd6e8..cb553a133be90d84643c97e59733137def5db3c8 100644
--- a/src/IceELFObjectWriter.cpp
+++ b/src/IceELFObjectWriter.cpp
@@ -512,11 +512,17 @@ template <typename ConstType> void ELFObjectWriter::writeConstantPool(Type Ty) {
 
   // If the -reorder-pooled-constant option is set to true, we should shuffle
   // the constants before we emit them.
-  auto *CtxPtr = &Ctx;
-  if (Ctx.getFlags().shouldReorderPooledConstants())
-    RandomShuffle(Pool.begin(), Pool.end(), [CtxPtr](uint64_t N) {
-      return (uint32_t)CtxPtr->getRNG().next(N);
-    });
+  if (Ctx.getFlags().shouldReorderPooledConstants()) {
+    if (!Pool.empty()) {

[Jim Stichnoth, 2015/08/19 19:03:04]

Can combine this and the above condition, as noted in another comment.

[qining, 2015/08/19 23:25:48]

Done.

+      // Use the constant's kind value as the salt for creating random number
+      // generator.
+      Operand::OperandKind K = (*Pool.begin())->getKind();
+      RandomNumberGenerator RNG(Ctx.getFlags().getRandomSeed(),
+                                RS_PooledConstantReordering, K);
+      RandomShuffle(Pool.begin(), Pool.end(),
+                    [&RNG](uint64_t N) { return (uint32_t)RNG.next(N); });
+    }
+  }
   // Write the data.
   for (Constant *C : Pool) {
     if (!C->getShouldBePooled())