1 files changed, 19 insertions, 5 deletions

diff --git a/lib/Transforms/Utils/AddDiscriminators.cpp b/lib/Transforms/Utils/AddDiscriminators.cpp
index 2e95926c0b3f..4c9746b8c691 100644
--- a/lib/Transforms/Utils/AddDiscriminators.cpp
+++ b/lib/Transforms/Utils/AddDiscriminators.cpp
@@ -102,6 +102,10 @@ FunctionPass *llvm::createAddDiscriminatorsPass() {
   return new AddDiscriminatorsLegacyPass();
 }
 
+static bool shouldHaveDiscriminator(const Instruction *I) {
+  return !isa<IntrinsicInst>(I) || isa<MemIntrinsic>(I);
+}
+
 /// \brief Assign DWARF discriminators.
 ///
 /// To assign discriminators, we examine the boundaries of every
@@ -176,7 +180,13 @@ static bool addDiscriminators(Function &F) {
   // discriminator for this instruction.
   for (BasicBlock &B : F) {
     for (auto &I : B.getInstList()) {
-      if (isa<IntrinsicInst>(&I))
+      // Not all intrinsic calls should have a discriminator.
+      // We want to avoid a non-deterministic assignment of discriminators at
+      // different debug levels. We still allow discriminators on memory
+      // intrinsic calls because those can be early expanded by SROA into
+      // pairs of loads and stores, and the expanded load/store instructions
+      // should have a valid discriminator.
+      if (!shouldHaveDiscriminator(&I))
         continue;
       const DILocation *DIL = I.getDebugLoc();
       if (!DIL)
@@ -190,8 +200,8 @@ static bool addDiscriminators(Function &F) {
       // discriminator is needed to distinguish both instructions.
       // Only the lowest 7 bits are used to represent a discriminator to fit
       // it in 1 byte ULEB128 representation.
-      unsigned Discriminator = (R.second ? ++LDM[L] : LDM[L]) & 0x7f;
-      I.setDebugLoc(DIL->cloneWithDiscriminator(Discriminator));
+      unsigned Discriminator = R.second ? ++LDM[L] : LDM[L];
+      I.setDebugLoc(DIL->setBaseDiscriminator(Discriminator));
       DEBUG(dbgs() << DIL->getFilename() << ":" << DIL->getLine() << ":"
                    << DIL->getColumn() << ":" << Discriminator << " " << I
                    << "\n");
@@ -207,6 +217,10 @@ static bool addDiscriminators(Function &F) {
     LocationSet CallLocations;
     for (auto &I : B.getInstList()) {
       CallInst *Current = dyn_cast<CallInst>(&I);
+      // We bypass intrinsic calls for the following two reasons:
+      //  1) We want to avoid a non-deterministic assigment of
+      //     discriminators.
+      //  2) We want to minimize the number of base discriminators used.
       if (!Current || isa<IntrinsicInst>(&I))
         continue;
 
@@ -216,8 +230,8 @@ static bool addDiscriminators(Function &F) {
       Location L =
           std::make_pair(CurrentDIL->getFilename(), CurrentDIL->getLine());
       if (!CallLocations.insert(L).second) {
-        Current->setDebugLoc(
-            CurrentDIL->cloneWithDiscriminator((++LDM[L]) & 0x7f));
+        unsigned Discriminator = ++LDM[L];
+        Current->setDebugLoc(CurrentDIL->setBaseDiscriminator(Discriminator));
         Changed = true;
       }
     }