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

[Rahman Lavaee via llvm-commits]

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@@ -1401,17 +1406,48 @@ void AsmPrinter::emitBBAddrMapSection(const MachineFunction &MF) {
   uint8_t BBAddrMapVersion = OutStreamer->getContext().getBBAddrMapVersion();
   OutStreamer->emitInt8(BBAddrMapVersion);
   OutStreamer->AddComment("feature");
-  auto FeaturesBits = static_cast<uint8_t>(PgoAnalysisMapFeatures.getBits());
-  OutStreamer->emitInt8(FeaturesBits);
-  OutStreamer->AddComment("function address");
-  OutStreamer->emitSymbolValue(FunctionSymbol, getPointerSize());
-  OutStreamer->AddComment("number of basic blocks");
-  OutStreamer->emitULEB128IntValue(MF.size());
-  const MCSymbol *PrevMBBEndSymbol = FunctionSymbol;
+  auto Features = getBBAddrMapFeature(MF, MBBSectionRanges.size());
+  OutStreamer->emitInt8(Features.encode());
   // Emit BB Information for each basic block in the function.
+  if (Features.MultiBBRange) {
+    OutStreamer->AddComment("number of basic block ranges");
+    OutStreamer->emitULEB128IntValue(MBBSectionRanges.size());
+  }
+  // Number of blocks in each MBB section.
+  MapVector<unsigned, unsigned> MBBSectionNumBlocks;
+  const MCSymbol *PrevMBBEndSymbol = nullptr;
+  if (!Features.MultiBBRange) {
+    OutStreamer->AddComment("function address");
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rlavaee wrote:

A second reason is backward and forward compatibility. As written, this PR does not change the encoding for the normal case. So we don't need to add a new version (which leads to even more technical debt).

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