[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.

Author: dpaoliello

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

@@ -226,6 +226,7 @@ class LVSymbolVisitor final : public SymbolVisitorCallbacks {
  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 @@ class LLVM_LIBRARY_VISIBILITY CodeViewDebug : public DebugHandlerBase {
  /// 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 @@ class LLVM_LIBRARY_VISIBILITY CodeViewDebug : public DebugHandlerBase {
  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: }