1 files changed, 28 insertions, 0 deletions
diff --git a/llvm/lib/Analysis/MemoryProfileInfo.cpp b/llvm/lib/Analysis/MemoryProfileInfo.cpp
index 0c1f8db..92a5b6f 100644
--- a/llvm/lib/Analysis/MemoryProfileInfo.cpp
+++ b/llvm/lib/Analysis/MemoryProfileInfo.cpp
@@ -54,6 +54,10 @@ cl::opt<unsigned> MinPercentMaxColdSize(
     "memprof-min-percent-max-cold-size", cl::init(100), cl::Hidden,
     cl::desc("Min percent of max cold bytes for critical cold context"));
 
+LLVM_ABI cl::opt<bool> MemProfUseAmbiguousAttributes(
+    "memprof-ambiguous-attributes", cl::init(true), cl::Hidden,
+    cl::desc("Apply ambiguous memprof attribute to ambiguous allocations"));
+
 } // end namespace llvm
 
 bool llvm::memprof::metadataIncludesAllContextSizeInfo() {
@@ -125,6 +129,26 @@ bool llvm::memprof::hasSingleAllocType(uint8_t AllocTypes) {
   return NumAllocTypes == 1;
 }
 
+void llvm::memprof::removeAnyExistingAmbiguousAttribute(CallBase *CB) {
+  if (!CB->hasFnAttr("memprof"))
+    return;
+  assert(CB->getFnAttr("memprof").getValueAsString() == "ambiguous");
+  CB->removeFnAttr("memprof");
+}
+
+void llvm::memprof::addAmbiguousAttribute(CallBase *CB) {
+  if (!MemProfUseAmbiguousAttributes)
+    return;
+  // We may have an existing ambiguous attribute if we are reanalyzing
+  // after inlining.
+  if (CB->hasFnAttr("memprof")) {
+    assert(CB->getFnAttr("memprof").getValueAsString() == "ambiguous");
+  } else {
+    auto A = llvm::Attribute::get(CB->getContext(), "memprof", "ambiguous");
+    CB->addFnAttr(A);
+  }
+}
+
 void CallStackTrie::addCallStack(
     AllocationType AllocType, ArrayRef<uint64_t> StackIds,
     std::vector<ContextTotalSize> ContextSizeInfo) {
@@ -470,6 +494,9 @@ void CallStackTrie::addSingleAllocTypeAttribute(CallBase *CI, AllocationType AT,
                                                 StringRef Descriptor) {
   auto AllocTypeString = getAllocTypeAttributeString(AT);
   auto A = llvm::Attribute::get(CI->getContext(), "memprof", AllocTypeString);
+  // After inlining we may be able to convert an existing ambiguous allocation
+  // to an unambiguous one.
+  removeAnyExistingAmbiguousAttribute(CI);
   CI->addFnAttr(A);
   if (MemProfReportHintedSizes) {
     std::vector<ContextTotalSize> ContextSizeInfo;
@@ -529,6 +556,7 @@ bool CallStackTrie::buildAndAttachMIBMetadata(CallBase *CI) {
     assert(MIBCallStack.size() == 1 &&
            "Should only be left with Alloc's location in stack");
     CI->setMetadata(LLVMContext::MD_memprof, MDNode::get(Ctx, MIBNodes));
+    addAmbiguousAttribute(CI);
     return true;
   }
   // If there exists corner case that CallStackTrie has one chain to leaf