Address comments

Author: vogelsgesang

llvm/docs/LangRef.rst

@@ -6983,10 +6983,13 @@ present in. The ``line:`` and ``column:`` field are the source line and column
 within the file where the label is declared.
 
 Furthermore, a label can be marked as artificial, i.e. compiler-generated,
-using ``isArtificial:``. Such artitificial labels are generated, e.g., by
+using ``isArtificial:``. Such artificial labels are generated, e.g., by
 the ``CoroSplit`` pass. In addition, the ``CoroSplit`` pass also uses the
 ``coroSuspendIdx:`` field to identify the coroutine suspend points.
 
+``scope:``, ``name:``, ``file:`` and ``line:`` are mandatory. The remaining
+fields are optional.
+
 .. code-block:: text
 
   !2 = !DILabel(scope: !0, name: "foo", file: !1, line: 7, column: 4)

llvm/lib/Bitcode/Reader/MetadataLoader.cpp

@@ -1133,7 +1133,6 @@ Error MetadataLoader::MetadataLoaderImpl::parseMetadata(bool ModuleLevel) {
     ++NumMDRecordLoaded;
     if (Expected<unsigned> MaybeCode =
             Stream.readRecord(Entry.ID, Record, &Blob)) {
-      // Crashes called from here!
       if (Error Err = parseOneMetadata(Record, MaybeCode.get(), Placeholders,
                                        Blob, NextMetadataNo))
         return Err;
@@ -1320,7 +1319,6 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
     unsigned Size = Record.size();
     NamedMDNode *NMD = TheModule.getOrInsertNamedMetadata(Name);
     for (unsigned i = 0; i != Size; ++i) {
-      // Crashes here!
       MDNode *MD = MetadataList.getMDNodeFwdRefOrNull(Record[i]);
       if (!MD)
         return error("Invalid named metadata: expect fwd ref to MDNode");
@@ -2251,8 +2249,8 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
     bool IsArtificial = Record[0] & 2;
     std::optional<unsigned> CoroSuspendIdx;
     if (Record.size() > 6) {
-      unsigned RawSuspendIdx = Record[6];
-      if (RawSuspendIdx != std::numeric_limits<unsigned>::max()) {
+      uint64_t RawSuspendIdx = Record[6];
+      if (RawSuspendIdx != std::numeric_limits<uint64_t>::max()) {
         if (RawSuspendIdx > (uint64_t)std::numeric_limits<unsigned>::max())
           return error("CoroSuspendIdx value is too large");
         CoroSuspendIdx = RawSuspendIdx;

llvm/lib/CodeGen/LiveDebugVariables.cpp

@@ -715,7 +715,6 @@ static void printExtendedName(raw_ostream &OS, const DINode *Node,
     Res = V->getName();
     Line = V->getLine();
   } else if (const auto *L = dyn_cast<const DILabel>(Node)) {
-    // XXX what are we doing here? Adjust it?
     Res = L->getName();
     Line = L->getLine();
   }

llvm/lib/Transforms/Coroutines/CoroFrame.cpp

@@ -689,8 +689,7 @@ static void buildFrameDebugInfo(Function &F, coro::Shape &Shape,
                                 FrameDataInfo &FrameData) {
   DISubprogram *DIS = F.getSubprogram();
   // If there is no DISubprogram for F, it implies the function is compiled
-  // without debug info. So we also don't generate debug info for the frame,
-  // either.
+  // without debug info. So we also don't generate debug info for the frame.
   if (!DIS || !DIS->getUnit() ||
       !dwarf::isCPlusPlus(
           (dwarf::SourceLanguage)DIS->getUnit()->getSourceLanguage()) ||

llvm/lib/Transforms/Coroutines/CoroSplit.cpp

@@ -1483,7 +1483,7 @@ struct SwitchCoroutineSplitter {
     DISubprogram *DIS = F.getSubprogram();
     // If there is no DISubprogram for F, it implies the function is compiled
     // without debug info. So we also don't generate debug info for the
-    // suspension points, either.
+    // suspension points.
     bool AddDebugLabels =
         (DIS && DIS->getUnit() &&
          (DIS->getUnit()->getEmissionKind() ==
@@ -1552,7 +1552,7 @@ struct SwitchCoroutineSplitter {
       //     br label %resume.0.landing
       //
       //  resume.0: ; <--- jump from the switch in the resume.entry
-      //     XXX: label
+      //        #dbg_label(...)  ; <--- artificial label for debuggers
       //     %0 = tail call i8 @llvm.coro.suspend(token none, i1 false)
       //     br label %resume.0.landing
       //

llvm/test/Transforms/Coroutines/coro-split-dbg-labels.ll

@@ -85,7 +85,7 @@ coro_Suspend:                                     ; preds = %for.cond, %if.then,
 ; CHECK: ![[DESTROY_1]] = !DILabel(scope: !{{[0-9]+}}, name: "__coro_resume_1", file: !{{[0-9]*}}, line: 14, column: 6, isArtificial: true, coroSuspendIdx: 1)
 
 ; DWARF:        {{.*}}DW_TAG_label
-; DWARF-LABEL:   DW_AT_name ("__coro_resume_0")
+; DWARF-NEXT:    DW_AT_name ("__coro_resume_0")
 ; DWARF-NEXT:    DW_AT_decl_file
 ; DWARF-NEXT:    DW_AT_decl_line    (12)
 ; DWARF-NEXT:    DW_AT_decl_column  (6)