Revert "[MemProf] Use radix tree for alloc contexts in bitcode summaries" (#117395)

Reverts llvm/llvm-project#117066

This is causing some build bot failures that need investigation.

1 files changed, 16 insertions, 55 deletions

diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index 11fbe6e..3e6abac 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 @@ private:
                                        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);