[llvm] Implement S_INLINEES debug symbol (#67490)

The `S_INLINEES` debug symbol is used to record all the functions that
are directly inlined within the current function (nested inlining is
ignored).

This change implements support for emitting the `S_INLINEES` debug
symbol in LLVM, and cleans up how the `S_INLINEES` and `S_CALLEES` debug
symbols are dumped.

1 files changed, 33 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
index b25a38b..335eccb 100644
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -250,7 +250,10 @@ CodeViewDebug::getInlineSite(const DILocation *InlinedAt,
         InlinedAt->getLine(), InlinedAt->getColumn(), SMLoc());
     Site->Inlinee = Inlinee;
     InlinedSubprograms.insert(Inlinee);
-    getFuncIdForSubprogram(Inlinee);
+    auto InlineeIdx = getFuncIdForSubprogram(Inlinee);
+
+    if (InlinedAt->getInlinedAt() == nullptr)
+      CurFn->Inlinees.insert(InlineeIdx);
   }
   return *Site;
 }
@@ -1194,6 +1197,7 @@ void CodeViewDebug::emitDebugInfoForFunction(const Function *GV,
     OS.emitInt32(uint32_t(FI.FrameProcOpts));
     endSymbolRecord(FrameProcEnd);
 
+    emitInlinees(FI.Inlinees);
     emitLocalVariableList(FI, FI.Locals);
     emitGlobalVariableList(FI.Globals);
     emitLexicalBlockList(FI.ChildBlocks, FI);
@@ -3588,3 +3592,31 @@ void CodeViewDebug::emitDebugInfoForJumpTables(const FunctionInfo &FI) {
     endSymbolRecord(JumpTableEnd);
   }
 }
+
+void CodeViewDebug::emitInlinees(
+    const SmallSet<codeview::TypeIndex, 1> &Inlinees) {
+  // Divide the list of inlinees into chunks such that each chunk fits within
+  // one record.
+  constexpr auto ChunkSize =
+      (MaxRecordLength - sizeof(SymbolKind) - sizeof(uint32_t)) /
+      sizeof(uint32_t);
+
+  SmallVector<TypeIndex> SortedInlinees{Inlinees.begin(), Inlinees.end()};
+  llvm::sort(SortedInlinees);
+
+  uint64_t CurrentIndex = 0;
+  while (CurrentIndex < SortedInlinees.size()) {
+    auto Symbol = beginSymbolRecord(SymbolKind::S_INLINEES);
+    auto CurrentChunkSize =
+        std::min(ChunkSize, SortedInlinees.size() - CurrentIndex);
+    OS.AddComment("Count");
+    OS.emitInt32(CurrentChunkSize);
+
+    const uint64_t CurrentChunkEnd = CurrentIndex + CurrentChunkSize;
+    for (; CurrentIndex < CurrentChunkEnd; ++CurrentIndex) {
+      OS.AddComment("Inlinee");
+      OS.emitInt32(SortedInlinees[CurrentIndex].getIndex());
+    }
+    endSymbolRecord(Symbol);
+  }
+}