Revert "[MemProf] Use radix tree for alloc contexts in bitcode summaries"

[teresajohnson]

Reverts #117066

This is causing some build bot failures that need investigation.

[llvmbot]

@llvm/pr-subscribers-pgo

@llvm/pr-subscribers-lto

Author: Teresa Johnson (teresajohnson)

Changes

Reverts llvm/llvm-project#117066

This is causing some build bot failures that need investigation.

---

Patch is 22.22 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/117395.diff

7 Files Affected:

• (modified) llvm/include/llvm/Bitcode/LLVMBitCodes.h (+3-7)
• (modified) llvm/lib/Bitcode/Reader/BitcodeAnalyzer.cpp (-1)
• (modified) llvm/lib/Bitcode/Reader/BitcodeReader.cpp (+16-55)
• (modified) llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (+11-147)
• (modified) llvm/lib/ProfileData/MemProf.cpp (-5)
• (removed) llvm/test/ThinLTO/X86/Inputs/memprof-old-alloc-context-summary.bc ()
• (removed) llvm/test/ThinLTO/X86/memprof-old-alloc-context-summary.ll (-28)

diff --git a/llvm/include/llvm/Bitcode/LLVMBitCodes.h b/llvm/include/llvm/Bitcode/LLVMBitCodes.h
index 41909a8fc1d590..a0fb32f67e3858 100644
--- a/llvm/include/llvm/Bitcode/LLVMBitCodes.h
+++ b/llvm/include/llvm/Bitcode/LLVMBitCodes.h
@@ -307,12 +307,12 @@ enum GlobalValueSummarySymtabCodes {
   // [valueid, n x stackidindex]
   FS_PERMODULE_CALLSITE_INFO = 26,
   // Summary of per-module allocation memprof metadata.
-  // [nummib, nummib x (alloc type, context radix tree index),
+  // [nummib, nummib x (alloc type, numstackids, numstackids x stackidindex),
   // [nummib x (numcontext x total size)]?]
   FS_PERMODULE_ALLOC_INFO = 27,
   // Summary of combined index memprof callsite metadata.
-  // [valueid, context radix tree index, numver,
-  //  numver x version]
+  // [valueid, numstackindices, numver,
+  //  numstackindices x stackidindex, numver x version]
   FS_COMBINED_CALLSITE_INFO = 28,
   // Summary of combined index allocation memprof metadata.
   // [nummib, numver,
@@ -331,10 +331,6 @@ enum GlobalValueSummarySymtabCodes {
   // the entries must be in the exact same order as the corresponding sizes.
   // [nummib x (numcontext x full stack id)]
   FS_ALLOC_CONTEXT_IDS = 31,
-  // Linearized radix tree of allocation contexts. See the description above the
-  // CallStackRadixTreeBuilder class in ProfileData/MemProf.h for format.
-  // [n x entry]
-  FS_CONTEXT_RADIX_TREE_ARRAY = 32,
 };
 
 enum MetadataCodes {
diff --git a/llvm/lib/Bitcode/Reader/BitcodeAnalyzer.cpp b/llvm/lib/Bitcode/Reader/BitcodeAnalyzer.cpp
index 032c0de3c7a00f..8f79ccdb9ff75f 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeAnalyzer.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeAnalyzer.cpp
@@ -329,7 +329,6 @@ GetCodeName(unsigned CodeID, unsigned BlockID,
       STRINGIFY_CODE(FS, COMBINED_ALLOC_INFO)
       STRINGIFY_CODE(FS, STACK_IDS)
       STRINGIFY_CODE(FS, ALLOC_CONTEXT_IDS)
-      STRINGIFY_CODE(FS, CONTEXT_RADIX_TREE_ARRAY)
     }
   case bitc::METADATA_ATTACHMENT_ID:
     switch (CodeID) {
diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index 11fbe6e6158eec..3e6abacac27261 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -987,10 +987,6 @@ class ModuleSummaryIndexBitcodeReader : public BitcodeReaderBase {
   /// ids from the lists in the callsite and alloc entries to the index.
   std::vector<uint64_t> StackIds;
 
-  /// Linearized radix tree of allocation contexts. See the description above
-  /// the CallStackRadixTreeBuilder class in ProfileData/MemProf.h for format.
-  std::vector<uint64_t> RadixArray;
-
 public:
   ModuleSummaryIndexBitcodeReader(
       BitstreamCursor Stream, StringRef Strtab, ModuleSummaryIndex &TheIndex,
@@ -1017,8 +1013,6 @@ class ModuleSummaryIndexBitcodeReader : public BitcodeReaderBase {
                                        TypeIdCompatibleVtableInfo &TypeId);
   std::vector<FunctionSummary::ParamAccess>
   parseParamAccesses(ArrayRef<uint64_t> Record);
-  SmallVector<unsigned> parseAllocInfoContext(ArrayRef<uint64_t> Record,
-                                              unsigned &I);
 
   template <bool AllowNullValueInfo = false>
   std::pair<ValueInfo, GlobalValue::GUID>
@@ -7550,48 +7544,6 @@ void ModuleSummaryIndexBitcodeReader::parseTypeIdCompatibleVtableSummaryRecord(
     parseTypeIdCompatibleVtableInfo(Record, Slot, TypeId);
 }
 
-SmallVector<unsigned> ModuleSummaryIndexBitcodeReader::parseAllocInfoContext(
-    ArrayRef<uint64_t> Record, unsigned &I) {
-  SmallVector<unsigned> StackIdList;
-  // For backwards compatibility with old format before radix tree was
-  // used, simply see if we found a radix tree array record (and thus if
-  // the RadixArray is non-empty).
-  if (RadixArray.empty()) {
-    unsigned NumStackEntries = Record[I++];
-    assert(Record.size() - I >= NumStackEntries);
-    StackIdList.reserve(NumStackEntries);
-    for (unsigned J = 0; J < NumStackEntries; J++) {
-      assert(Record[I] < StackIds.size());
-      StackIdList.push_back(
-          TheIndex.addOrGetStackIdIndex(StackIds[Record[I++]]));
-    }
-  } else {
-    unsigned RadixIndex = Record[I++];
-    // See the comments above CallStackRadixTreeBuilder in ProfileData/MemProf.h
-    // for a detailed description of the radix tree array format. Briefly, the
-    // first entry will be the number of frames, any negative values are the
-    // negative of the offset of the next frame, and otherwise the frames are in
-    // increasing linear order.
-    assert(RadixIndex < RadixArray.size());
-    unsigned NumStackIds = RadixArray[RadixIndex++];
-    StackIdList.reserve(NumStackIds);
-    while (NumStackIds--) {
-      assert(RadixIndex < RadixArray.size());
-      unsigned Elem = RadixArray[RadixIndex];
-      if (static_cast<std::make_signed_t<unsigned>>(Elem) < 0) {
-        RadixIndex = RadixIndex - Elem;
-        assert(RadixIndex < RadixArray.size());
-        Elem = RadixArray[RadixIndex];
-        // We shouldn't encounter a second offset in a row.
-        assert(static_cast<std::make_signed_t<unsigned>>(Elem) >= 0);
-      }
-      RadixIndex++;
-      StackIdList.push_back(TheIndex.addOrGetStackIdIndex(StackIds[Elem]));
-    }
-  }
-  return StackIdList;
-}
-
 static void setSpecialRefs(SmallVectorImpl<ValueInfo> &Refs, unsigned ROCnt,
                            unsigned WOCnt) {
   // Readonly and writeonly refs are in the end of the refs list.
@@ -8058,11 +8010,6 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(unsigned ID) {
       break;
     }
 
-    case bitc::FS_CONTEXT_RADIX_TREE_ARRAY: { // [n x entry]
-      RadixArray = ArrayRef<uint64_t>(Record);
-      break;
-    }
-
     case bitc::FS_PERMODULE_CALLSITE_INFO: {
       unsigned ValueID = Record[0];
       SmallVector<unsigned> StackIdList;
@@ -8118,7 +8065,14 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(unsigned ID) {
              (Version < 10 && I < Record.size())) {
         assert(Record.size() - I >= 2);
         AllocationType AllocType = (AllocationType)Record[I++];
-        auto StackIdList = parseAllocInfoContext(Record, I);
+        unsigned NumStackEntries = Record[I++];
+        assert(Record.size() - I >= NumStackEntries);
+        SmallVector<unsigned> StackIdList;
+        for (unsigned J = 0; J < NumStackEntries; J++) {
+          assert(Record[I] < StackIds.size());
+          StackIdList.push_back(
+              TheIndex.addOrGetStackIdIndex(StackIds[Record[I++]]));
+        }
         MIBs.push_back(MIBInfo(AllocType, std::move(StackIdList)));
       }
       // We either have nothing left or at least NumMIBs context size info
@@ -8169,7 +8123,14 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(unsigned ID) {
       while (MIBsRead++ < NumMIBs) {
         assert(Record.size() - I >= 2);
         AllocationType AllocType = (AllocationType)Record[I++];
-        auto StackIdList = parseAllocInfoContext(Record, I);
+        unsigned NumStackEntries = Record[I++];
+        assert(Record.size() - I >= NumStackEntries);
+        SmallVector<unsigned> StackIdList;
+        for (unsigned J = 0; J < NumStackEntries; J++) {
+          assert(Record[I] < StackIds.size());
+          StackIdList.push_back(
+              TheIndex.addOrGetStackIdIndex(StackIds[Record[I++]]));
+        }
         MIBs.push_back(MIBInfo(AllocType, std::move(StackIdList)));
       }
       assert(Record.size() - I >= NumVersions);
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 8f22a50a5e0245..59e070a5110620 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -60,7 +60,6 @@
 #include "llvm/MC/StringTableBuilder.h"
 #include "llvm/MC/TargetRegistry.h"
 #include "llvm/Object/IRSymtab.h"
-#include "llvm/ProfileData/MemProf.h"
 #include "llvm/Support/AtomicOrdering.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/CommandLine.h"
@@ -84,7 +83,6 @@
 #include <vector>
 
 using namespace llvm;
-using namespace llvm::memprof;
 
 static cl::opt<unsigned>
     IndexThreshold("bitcode-mdindex-threshold", cl::Hidden, cl::init(25),
@@ -233,8 +231,7 @@ class ModuleBitcodeWriterBase : public BitcodeWriterBase {
       SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
       unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
       unsigned CallsiteAbbrev, unsigned AllocAbbrev, unsigned ContextIdAbbvId,
-      const Function &F, DenseMap<CallStackId, LinearCallStackId> &CallStackPos,
-      CallStackId &CallStackCount);
+      const Function &F);
   void writeModuleLevelReferences(const GlobalVariable &V,
                                   SmallVector<uint64_t, 64> &NameVals,
                                   unsigned FSModRefsAbbrev,
@@ -4198,58 +4195,12 @@ static void writeTypeIdCompatibleVtableSummaryRecord(
   }
 }
 
-// Adds the allocation contexts to the CallStacks map. We simply use the
-// size at the time the context was added as the CallStackId. This works because
-// when we look up the call stacks later on we process the function summaries
-// and their allocation records in the same exact order.
-static void collectMemProfCallStacks(
-    FunctionSummary *FS, std::function<LinearFrameId(unsigned)> GetStackIndex,
-    MapVector<CallStackId, llvm::SmallVector<LinearFrameId>> &CallStacks) {
-  // The interfaces in ProfileData/MemProf.h use a type alias for a stack frame
-  // id offset into the index of the full stack frames. The ModuleSummaryIndex
-  // currently uses unsigned. Make sure these stay in sync.
-  static_assert(std::is_same_v<LinearFrameId, unsigned>);
-  for (auto &AI : FS->allocs()) {
-    for (auto &MIB : AI.MIBs) {
-      SmallVector<unsigned> StackIdIndices;
-      StackIdIndices.reserve(MIB.StackIdIndices.size());
-      for (auto Id : MIB.StackIdIndices)
-        StackIdIndices.push_back(GetStackIndex(Id));
-      // The CallStackId is the size at the time this context was inserted.
-      CallStacks.insert({CallStacks.size(), StackIdIndices});
-    }
-  }
-}
-
-// Build the radix tree from the accumulated CallStacks, write out the resulting
-// linearized radix tree array, and return the map of call stack positions into
-// this array for use when writing the allocation records. The returned map is
-// indexed by a CallStackId which in this case is implicitly determined by the
-// order of function summaries and their allocation infos being written.
-static DenseMap<CallStackId, LinearCallStackId> writeMemoryProfileRadixTree(
-    MapVector<CallStackId, llvm::SmallVector<LinearFrameId>> &&CallStacks,
-    BitstreamWriter &Stream, unsigned RadixAbbrev) {
-  assert(!CallStacks.empty());
-  DenseMap<unsigned, FrameStat> FrameHistogram =
-      computeFrameHistogram<LinearFrameId>(CallStacks);
-  CallStackRadixTreeBuilder<LinearFrameId> Builder;
-  // We don't need a MemProfFrameIndexes map as we have already converted the
-  // full stack id hash to a linear offset into the StackIds array.
-  Builder.build(std::move(CallStacks), /*MemProfFrameIndexes=*/std::nullopt,
-                FrameHistogram);
-  Stream.EmitRecord(bitc::FS_CONTEXT_RADIX_TREE_ARRAY, Builder.getRadixArray(),
-                    RadixAbbrev);
-  return Builder.takeCallStackPos();
-}
-
 static void writeFunctionHeapProfileRecords(
     BitstreamWriter &Stream, FunctionSummary *FS, unsigned CallsiteAbbrev,
     unsigned AllocAbbrev, unsigned ContextIdAbbvId, bool PerModule,
     std::function<unsigned(const ValueInfo &VI)> GetValueID,
     std::function<unsigned(unsigned)> GetStackIndex,
-    bool WriteContextSizeInfoIndex,
-    DenseMap<CallStackId, LinearCallStackId> &CallStackPos,
-    CallStackId &CallStackCount) {
+    bool WriteContextSizeInfoIndex) {
   SmallVector<uint64_t> Record;
 
   for (auto &CI : FS->callsites()) {
@@ -4283,9 +4234,9 @@ static void writeFunctionHeapProfileRecords(
       Record.push_back(AI.Versions.size());
     for (auto &MIB : AI.MIBs) {
       Record.push_back((uint8_t)MIB.AllocType);
-      // Record the index into the radix tree array for this context.
-      assert(CallStackCount <= CallStackPos.size());
-      Record.push_back(CallStackPos[CallStackCount++]);
+      Record.push_back(MIB.StackIdIndices.size());
+      for (auto Id : MIB.StackIdIndices)
+        Record.push_back(GetStackIndex(Id));
     }
     if (!PerModule) {
       for (auto V : AI.Versions)
@@ -4331,9 +4282,7 @@ void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
     unsigned ValueID, unsigned FSCallsRelBFAbbrev,
     unsigned FSCallsProfileAbbrev, unsigned CallsiteAbbrev,
-    unsigned AllocAbbrev, unsigned ContextIdAbbvId, const Function &F,
-    DenseMap<CallStackId, LinearCallStackId> &CallStackPos,
-    CallStackId &CallStackCount) {
+    unsigned AllocAbbrev, unsigned ContextIdAbbvId, const Function &F) {
   NameVals.push_back(ValueID);
 
   FunctionSummary *FS = cast<FunctionSummary>(Summary);
@@ -4348,7 +4297,7 @@ void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
       /*PerModule*/ true,
       /*GetValueId*/ [&](const ValueInfo &VI) { return getValueId(VI); },
       /*GetStackIndex*/ [&](unsigned I) { return I; },
-      /*WriteContextSizeInfoIndex*/ true, CallStackPos, CallStackCount);
+      /*WriteContextSizeInfoIndex*/ true);
 
   auto SpecialRefCnts = FS->specialRefCounts();
   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
@@ -4581,54 +4530,12 @@ void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
   Abbv = std::make_shared<BitCodeAbbrev>();
   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_ALLOC_INFO));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // nummib
-  // n x (alloc type, context radix tree index)
+  // n x (alloc type, numstackids, numstackids x stackidindex)
   // optional: nummib x (numcontext x total size)
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
 
-  Abbv = std::make_shared<BitCodeAbbrev>();
-  Abbv->Add(BitCodeAbbrevOp(bitc::FS_CONTEXT_RADIX_TREE_ARRAY));
-  // n x entry
-  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
-  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
-  unsigned RadixAbbrev = Stream.EmitAbbrev(std::move(Abbv));
-
-  // First walk through all the functions and collect the allocation contexts in
-  // their associated summaries, for use in constructing a radix tree of
-  // contexts. Note that we need to do this in the same order as the functions
-  // are processed further below since the call stack positions in the resulting
-  // radix tree array are identified based on this order.
-  MapVector<CallStackId, llvm::SmallVector<LinearFrameId>> CallStacks;
-  for (const Function &F : M) {
-    // Summary emission does not support anonymous functions, they have to be
-    // renamed using the anonymous function renaming pass.
-    if (!F.hasName())
-      report_fatal_error("Unexpected anonymous function when writing summary");
-
-    ValueInfo VI = Index->getValueInfo(F.getGUID());
-    if (!VI || VI.getSummaryList().empty()) {
-      // Only declarations should not have a summary (a declaration might
-      // however have a summary if the def was in module level asm).
-      assert(F.isDeclaration());
-      continue;
-    }
-    auto *Summary = VI.getSummaryList()[0].get();
-    FunctionSummary *FS = cast<FunctionSummary>(Summary);
-    collectMemProfCallStacks(
-        FS, /*GetStackIndex*/ [](unsigned I) { return I; }, CallStacks);
-  }
-  // Finalize the radix tree, write it out, and get the map of positions in the
-  // linearized tree array.
-  DenseMap<CallStackId, LinearCallStackId> CallStackPos;
-  if (!CallStacks.empty()) {
-    CallStackPos =
-        writeMemoryProfileRadixTree(std::move(CallStacks), Stream, RadixAbbrev);
-  }
-
-  // Keep track of the current index into the CallStackPos map.
-  CallStackId CallStackCount = 0;
-
   SmallVector<uint64_t, 64> NameVals;
   // Iterate over the list of functions instead of the Index to
   // ensure the ordering is stable.
@@ -4648,8 +4555,7 @@ void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
     auto *Summary = VI.getSummaryList()[0].get();
     writePerModuleFunctionSummaryRecord(
         NameVals, Summary, VE.getValueID(&F), FSCallsRelBFAbbrev,
-        FSCallsProfileAbbrev, CallsiteAbbrev, AllocAbbrev, ContextIdAbbvId, F,
-        CallStackPos, CallStackCount);
+        FSCallsProfileAbbrev, CallsiteAbbrev, AllocAbbrev, ContextIdAbbvId, F);
   }
 
   // Capture references from GlobalVariable initializers, which are outside
@@ -4786,20 +4692,13 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALLOC_INFO));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // nummib
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numver
-  // nummib x (alloc type, context radix tree index),
+  // nummib x (alloc type, numstackids, numstackids x stackidindex),
   // numver x version
   // optional: nummib x total size
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
 
-  Abbv = std::make_shared<BitCodeAbbrev>();
-  Abbv->Add(BitCodeAbbrevOp(bitc::FS_CONTEXT_RADIX_TREE_ARRAY));
-  // n x entry
-  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
-  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
-  unsigned RadixAbbrev = Stream.EmitAbbrev(std::move(Abbv));
-
   auto shouldImportValueAsDecl = [&](GlobalValueSummary *GVS) -> bool {
     if (DecSummaries == nullptr)
       return false;
@@ -4836,41 +4735,6 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
     NameVals.clear();
   };
 
-  // First walk through all the functions and collect the allocation contexts in
-  // their associated summaries, for use in constructing a radix tree of
-  // contexts. Note that we need to do this in the same order as the functions
-  // are processed further below since the call stack positions in the resulting
-  // radix tree array are identified based on this order.
-  MapVector<CallStackId, llvm::SmallVector<LinearFrameId>> CallStacks;
-  forEachSummary([&](GVInfo I, bool IsAliasee) {
-    GlobalValueSummary *S = I.second;
-    assert(S);
-    auto *FS = dyn_cast<FunctionSummary>(S);
-    if (!FS)
-      return;
-    collectMemProfCallStacks(
-        FS,
-        /*GetStackIndex*/
-        [&](unsigned I) {
-          // Get the corresponding index into the list of StackIds actually
-          // being written for this combined index (which may be a subset in
-          // the case of distributed indexes).
-          assert(StackIdIndicesToIndex.contains(I));
-          return StackIdIndicesToIndex[I];
-        },
-        CallStacks);
-  });
-  // Finalize the radix tree, write it out, and get the map of positions in the
-  // linearized tree array.
-  DenseMap<CallStackId, LinearCallStackId> CallStackPos;
-  if (!CallStacks.empty()) {
-    CallStackPos =
-        writeMemoryProfileRadixTree(std::move(CallStacks), Stream, RadixAbbrev);
-  }
-
-  // Keep track of the current index into the CallStackPos map.
-  CallStackId CallStackCount = 0;
-
   DenseSet<GlobalValue::GUID> DefOrUseGUIDs;
   forEachSummary([&](GVInfo I, bool IsAliasee) {
     GlobalValueSummary *S = I.second;
@@ -4949,7 +4813,7 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
           assert(StackIdIndicesToIndex.contains(I));
           return StackIdIndicesToIndex[I];
         },
-        /*WriteContextSizeInfoIndex*/ false, CallStackPos, CallStackCount);
+        /*WriteContextSizeInfoIndex*/ false);
 
     NameVals.push_back(*ValueId);
     assert(ModuleIdMap.count(FS->modulePath()));
diff --git a/llvm/lib/ProfileData/MemProf.cpp b/llvm/lib/ProfileData/MemProf.cpp
index 70741ee4850bd8..9615fdf77eb27e 100644
--- a/llvm/lib/ProfileData/MemProf.cpp
+++ b/llvm/lib/ProfileData/MemProf.cpp
@@ -510,7 +510,6 @@ void CallStackRadixTreeBuilder<FrameIdTy>::build(
 
 // Explicitly instantiate class with the utilized FrameIdTy.
 template class CallStackRadixTreeBuilder<FrameId>;
-template class CallStackRadixTreeBuilder<LinearFrameId>;
 
 template <typen...
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