[llvm] [clang] [lld] [SHT_LLVM_BB_ADDR_MAP] Allow basic-block-sections and labels be used together by decoupling the handling of the two features. (PR #74128)

[Micah Weston via cfe-commits]

================
@@ -719,60 +730,83 @@ decodeBBAddrMapImpl(const ELFFile<ELFT> &EF,
       Feature = Data.getU8(Cur); // Feature byte
       if (!Cur)
         break;
-      auto FeatEnableOrErr = PGOAnalysisMap::Features::decode(Feature);
+      auto FeatEnableOrErr = BBAddrMap::Features::decode(Feature);
       if (!FeatEnableOrErr)
         return FeatEnableOrErr.takeError();
-      FeatEnable =
-          FeatEnableOrErr ? *FeatEnableOrErr : PGOAnalysisMap::Features{};
+      FeatEnable = FeatEnableOrErr ? *FeatEnableOrErr : BBAddrMap::Features{};
       if (Feature != 0 && Version < 2 && Cur)
         return createError(
             "version should be >= 2 for SHT_LLVM_BB_ADDR_MAP when "
             "PGO features are enabled: version = " +
             Twine(static_cast<int>(Version)) +
             " feature = " + Twine(static_cast<int>(Feature)));
     }
-    uint64_t SectionOffset = Cur.tell();
-    auto Address =
-        static_cast<typename ELFFile<ELFT>::uintX_t>(Data.getAddress(Cur));
-    if (!Cur)
-      return Cur.takeError();
-    if (IsRelocatable) {
-      assert(Address == 0);
-      auto FOTIterator = FunctionOffsetTranslations.find(SectionOffset);
-      if (FOTIterator == FunctionOffsetTranslations.end()) {
-        return createError("failed to get relocation data for offset: " +
-                           Twine::utohexstr(SectionOffset) + " in section " +
-                           describe(EF, Sec));
-      }
-      Address = FOTIterator->second;
-    }
-    uint32_t NumBlocks = readULEB128As<uint32_t>(Data, Cur, ULEBSizeErr);
-
+    uint32_t NumBlocksInBBRange = 0;
+    uint32_t NumBBRanges = 1;
+    typename ELFFile<ELFT>::uintX_t RangeBaseAddress = 0;
     std::vector<BBAddrMap::BBEntry> BBEntries;
-    uint32_t PrevBBEndOffset = 0;
-    for (uint32_t BlockIndex = 0;
-         !MetadataDecodeErr && !ULEBSizeErr && Cur && (BlockIndex < NumBlocks);
-         ++BlockIndex) {
-      uint32_t ID = Version >= 2
-                        ? readULEB128As<uint32_t>(Data, Cur, ULEBSizeErr)
-                        : BlockIndex;
-      uint32_t Offset = readULEB128As<uint32_t>(Data, Cur, ULEBSizeErr);
-      uint32_t Size = readULEB128As<uint32_t>(Data, Cur, ULEBSizeErr);
-      uint32_t MD = readULEB128As<uint32_t>(Data, Cur, ULEBSizeErr);
-      if (Version >= 1) {
-        // Offset is calculated relative to the end of the previous BB.
-        Offset += PrevBBEndOffset;
-        PrevBBEndOffset = Offset + Size;
+    if (FeatEnable.MultiBBRange) {
+      NumBBRanges = readULEB128As<uint32_t>(Data, Cur, ULEBSizeErr);
+    } else {
+      uint64_t RelocationOffsetInSection = Cur.tell();
+      RangeBaseAddress =
+          static_cast<typename ELFFile<ELFT>::uintX_t>(Data.getAddress(Cur));
+      if (!Cur)
+        return Cur.takeError();
+      if (IsRelocatable) {
+        Expected<unsigned> AddressOrErr =
+            GetAddressForRelocation(RelocationOffsetInSection);
+        if (!AddressOrErr)
+          return AddressOrErr.takeError();
+        RangeBaseAddress = *AddressOrErr;
       }
-      Expected<BBAddrMap::BBEntry::Metadata> MetadataOrErr =
-          BBAddrMap::BBEntry::Metadata::decode(MD);
-      if (!MetadataOrErr) {
-        MetadataDecodeErr = MetadataOrErr.takeError();
-        break;
+      NumBlocksInBBRange = readULEB128As<uint32_t>(Data, Cur, ULEBSizeErr);
+    }
+    std::vector<BBAddrMap::BBRangeEntry> BBRangeEntries;
+    uint32_t TotalNumBlocks = 0;
+    for (uint32_t BBRangeIndex = 0; BBRangeIndex < NumBBRanges;
+         ++BBRangeIndex) {
+      uint32_t PrevBBEndOffset = 0;
+      if (FeatEnable.MultiBBRange) {
+        uint64_t RelocationOffsetInSection = Cur.tell();
+        RangeBaseAddress =
+            static_cast<typename ELFFile<ELFT>::uintX_t>(Data.getAddress(Cur));
+        if (IsRelocatable) {
+          assert(RangeBaseAddress == 0);
+          Expected<unsigned> AddressOrErr =
+              GetAddressForRelocation(RelocationOffsetInSection);
+          if (!AddressOrErr)
+            return AddressOrErr.takeError();
+          RangeBaseAddress = *AddressOrErr;
+        }
+        NumBlocksInBBRange = readULEB128As<uint32_t>(Data, Cur, ULEBSizeErr);
----------------
red1bluelost wrote:

This seems nearly the same as at line 751. The differences seem to be this has an assert on the RangeBaseAddress and 751 short circuits on Cur. If it is possible, could it be moved into a lambda so that this and 751 can just call the lambda?

https://github.com/llvm/llvm-project/pull/74128