[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.

llvm/include/llvm/DebugInfo/LogicalView/Readers/LVCodeViewVisitor.h

@@ -226,6 +226,7 @@ public:
   Error visitKnownRecord(CVSymbol &Record, UDTSym &UDT) override;
   Error visitKnownRecord(CVSymbol &Record, UsingNamespaceSym &UN) override;
   Error visitKnownRecord(CVSymbol &Record, JumpTableSym &JumpTable) override;
+  Error visitKnownRecord(CVSymbol &Record, CallerSym &Caller) override;
 };
 
 // Visitor for CodeView types and symbols to populate elements.

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);
+  }
+}

llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.h

@@ -20,6 +20,7 @@
 #include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/PointerUnion.h"
 #include "llvm/ADT/SetVector.h"
+#include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/CodeGen/DbgEntityHistoryCalculator.h"
 #include "llvm/CodeGen/DebugHandlerBase.h"
@@ -158,6 +159,9 @@ private:
     /// Ordered list of top-level inlined call sites.
     SmallVector<const DILocation *, 1> ChildSites;
 
+    /// Set of all functions directly inlined into this one.
+    SmallSet<codeview::TypeIndex, 1> Inlinees;
+
     SmallVector<LocalVariable, 1> Locals;
     SmallVector<CVGlobalVariable, 1> Globals;
 
@@ -371,6 +375,8 @@ private:
   void emitInlinedCallSite(const FunctionInfo &FI, const DILocation *InlinedAt,
                            const InlineSite &Site);
 
+  void emitInlinees(const SmallSet<codeview::TypeIndex, 1> &Inlinees);
+
   using InlinedEntity = DbgValueHistoryMap::InlinedEntity;
 
   void collectGlobalVariableInfo();

llvm/lib/DebugInfo/CodeView/SymbolDumper.cpp

@@ -589,7 +589,22 @@ Error CVSymbolDumperImpl::visitKnownRecord(CVSymbol &CVR,
 }
 
 Error CVSymbolDumperImpl::visitKnownRecord(CVSymbol &CVR, CallerSym &Caller) {
-  ListScope S(W, CVR.kind() == S_CALLEES ? "Callees" : "Callers");
+  llvm::StringRef ScopeName;
+  switch (CVR.kind()) {
+  case S_CALLEES:
+    ScopeName = "Callees";
+    break;
+  case S_CALLERS:
+    ScopeName = "Callers";
+    break;
+  case S_INLINEES:
+    ScopeName = "Inlinees";
+    break;
+  default:
+    return llvm::make_error<CodeViewError>(
+        "Unknown CV Record type for a CallerSym object!");
+  }
+  ListScope S(W, ScopeName);
   for (auto FuncID : Caller.Indices)
     printTypeIndex("FuncID", FuncID);
   return Error::success();

llvm/lib/DebugInfo/LogicalView/Readers/LVCodeViewVisitor.cpp

@@ -1705,6 +1705,31 @@ Error LVSymbolVisitor::visitKnownRecord(CVSymbol &CVR,
   return Error::success();
 }
 
+// S_CALLERS, S_CALLEES, S_INLINEES
+Error LVSymbolVisitor::visitKnownRecord(CVSymbol &Record, CallerSym &Caller) {
+  LLVM_DEBUG({
+    llvm::StringRef FieldName;
+    switch (Caller.getKind()) {
+    case SymbolRecordKind::CallerSym:
+      FieldName = "Callee";
+      break;
+    case SymbolRecordKind::CalleeSym:
+      FieldName = "Caller";
+      break;
+    case SymbolRecordKind::InlineesSym:
+      FieldName = "Inlinee";
+      break;
+    default:
+      return llvm::make_error<CodeViewError>(
+          "Unknown CV Record type for a CallerSym object!");
+    }
+    for (auto FuncID : Caller.Indices) {
+      printTypeIndex(FieldName, FuncID);
+    }
+  });
+  return Error::success();
+}
+
 #undef DEBUG_TYPE
 #define DEBUG_TYPE "CodeViewLogicalVisitor"
 

llvm/test/DebugInfo/COFF/inlining-files.ll

@@ -21,6 +21,12 @@
 ; OBJ:    {{.*}}Proc{{.*}}Sym {
 ; OBJ:      DisplayName: f
 ; OBJ:    }
+; OBJ:     InlineesSym {
+; OBJ-NEXT:  Kind: S_INLINEES (0x1168)
+; OBJ-NEXT:  Inlinees [
+; OBJ-NEXT:    FuncID: file_change (0x1002)
+; OBJ-NEXT:  ]
+; OBJ-NEXT:}
 ; OBJ:    InlineSiteSym {
 ; OBJ:      PtrParent: 0x0
 ; OBJ:      PtrEnd: 0x0

llvm/test/DebugInfo/COFF/inlining-header.ll

@@ -75,6 +75,13 @@
 ; OBJ:     LinkageName: _main
 ; OBJ:   }
 
+; OBJ:        InlineesSym {
+; OBJ-NEXT:     Kind: S_INLINEES (0x1168)
+; OBJ-NEXT:     Inlinees [
+; OBJ-NEXT:       FuncID: g (0x1002)
+; OBJ-NEXT:     ]
+; OBJ-NEXT:   }
+
 ; Previously, g's InlineSiteSym referenced t.h, which was wasteful.
 ; OBJ:        InlineSiteSym {
 ; OBJ:          Inlinee: g (0x1002)

llvm/test/DebugInfo/COFF/inlining-levels.ll

@@ -19,6 +19,12 @@
 ; OBJ: Subsection [
 ; OBJ:   SubSectionType: Symbols (0xF1)
 ; OBJ:   {{.*}}Proc{{.*}}Sym {
+; OBJ:   InlineesSym {
+; OBJ-NEXT:  Kind: S_INLINEES (0x1168)
+; OBJ-NEXT:  Inlinees [
+; OBJ-NEXT:    FuncID: h (0x1002)
+; OBJ-NEXT:  ]
+; OBJ-NEXT:}
 ; OBJ:   InlineSiteSym {
 ; OBJ:     Inlinee: h (0x1002)
 ; OBJ:   }

llvm/test/DebugInfo/COFF/inlining-padding.ll

@@ -33,6 +33,15 @@
 ; CHECK:    )
 ; CHECK:  }
 
+; CHECK:      InlineesSym {
+; CHECK-NEXT:   Kind: S_INLINEES (0x1168)
+; CHECK-NEXT:   Inlinees [
+; CHECK-NEXT:     FuncID: a (0x1002)
+; CHECK-NEXT:     FuncID: ab (0x1003)
+; CHECK-NEXT:     FuncID: abc (0x1004)
+; CHECK-NEXT:     FuncID: abcd (0x1005)
+; CHECK-NEXT:   ]
+
 ; C++ source used to generate the IR:
 ;
 ; extern volatile int x;

llvm/test/DebugInfo/COFF/inlining-same-name.ll

@@ -18,6 +18,12 @@
 ; CHECK:     {{.*}}Proc{{.*}}Sym {
 ; CHECK:       DisplayName: main
 ; CHECK:     }
+; CHECK:     InlineesSym {
+; CHECK-NEXT:  Kind: S_INLINEES (0x1168)
+; CHECK-NEXT:  Inlinees [
+; CHECK-NEXT:    FuncID: same_name (0x1002)
+; CHECK-NEXT:  ]
+; CHECK-NEXT:}
 ; CHECK:     InlineSiteSym {
 ; CHECK:       Inlinee: same_name (0x1002)
 ; CHECK:     }

llvm/test/DebugInfo/COFF/inlining.ll

@@ -166,6 +166,12 @@
 ; OBJ:     DisplayName: baz
 ; OBJ:     LinkageName: ?baz@@YAXXZ
 ; OBJ:   }
+; OBJ:   InlineesSym {
+; OBJ-NEXT:  Kind: S_INLINEES (0x1168)
+; OBJ-NEXT:  Inlinees [
+; OBJ-NEXT:    FuncID: bar (0x1002)
+; OBJ-NEXT:  ]
+; OBJ-NEXT:}
 ; OBJ:   InlineSiteSym {
 ; OBJ:     PtrParent: 0x0
 ; OBJ:     PtrEnd: 0x0

llvm/test/tools/llvm-readobj/COFF/codeview-inlinees.test

@@ -28,7 +28,7 @@ CHECK:      Kind: S_INLINESITE (0x114D)
 CHECK:      Inlinee: f (0x1003)
 CHECK:    InlineesSym {
 CHECK-NEXT:      Kind: S_INLINEES (0x1168)
-CHECK-NEXT:      Callers [
+CHECK-NEXT:      Inlinees [
 CHECK-NEXT:        FuncID: f (0x1003)
 CHECK-NEXT:        FuncID: h (0x1004)
 CHECK-NEXT:      ]

llvm/tools/llvm-pdbutil/MinimalSymbolDumper.cpp

@@ -875,9 +875,24 @@ Error MinimalSymbolDumper::visitKnownRecord(CVSymbol &CVR,
 }
 
 Error MinimalSymbolDumper::visitKnownRecord(CVSymbol &CVR, CallerSym &Caller) {
+  const char *Format;
+  switch (CVR.kind()) {
+  case S_CALLEES:
+    Format = "callee: {0}";
+    break;
+  case S_CALLERS:
+    Format = "caller: {0}";
+    break;
+  case S_INLINEES:
+    Format = "inlinee: {0}";
+    break;
+  default:
+    return llvm::make_error<CodeViewError>(
+        "Unknown CV Record type for a CallerSym object!");
+  }
   AutoIndent Indent(P, 7);
   for (const auto &I : Caller.Indices) {
-    P.formatLine("callee: {0}", idIndex(I));
+    P.formatLine(Format, idIndex(I));
   }
   return Error::success();
 }