Add llvm.codeview.annotation to implement MSVC __annotation

[rnk]

Summary

This intrinsic represents a label with a list of associated metadata
strings. It is not zero-cost, since it is modelled as reading and
writing memory.

MSVC does not clone annotations when inlining, so we follow suit.

[majnemer]

llvm/include/llvm/IR/Intrinsics.td

638

This seems wrong: https://godbolt.org/g/ZCpdBY

[majnemer]

I wonder if the right way to model it is with inaccessiblememonly?

[rnk]

In D36904#846066, @majnemer wrote:

I wonder if the right way to model it is with inaccessiblememonly?

Oh, I forgot about that.

In general, I was just aiming for something conservatively correct that would survive the optimizer at all costs. It should be code generated at most once (so noduplicate). In practice, MSVC removes annotations during inlining, and does not appear to duplicate them in any other way. We could try lambdas or other tricks that force them to double-emit them, though.

[rnk]

• Use inaccessiblememonly

[majnemer]

LGTM

llvm/docs/LangRef.rst

 Semantics:
 """"""""""
 
 This intrinsic allows annotations to be put on arbitrary expressions
 with arbitrary strings. This can be useful for special purpose
 optimizations that want to look for these annotations. These have no
 other defined use; they are ignored by code generation and optimization.
 
+'``llvm.codeview.annotation``' Intrinsic
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Syntax:
+"""""""
+
+This annotation emits a label at its program point and an associated
+``S_ANNOTATION`` codeview record with some additional string metadata. It is
+modelled as reading and writing memory, so loads and stores cannot be reordered
+past it. This is used to implement MSVC's ``__annotation`` intrinsic.
+
+::
+
+      declare void @llvm.label.annotation(metadata)
+
+Arguments:
+""""""""""
+
+The argument should be an MDTuple containing any number of MDStrings.
+
 '``llvm.trap``' Intrinsic
 ^^^^^^^^^^^^^^^^^^^^^^^^^
 
 Syntax:
 """""""
 
 ::
 

llvm/include/llvm/CodeGen/ISDOpcodes.h

enum NodeType {
     /// SDOperands.
     INLINEASM,
 
     /// EH_LABEL - Represents a label in mid basic block used to track
     /// locations needed for debug and exception handling tables.  These nodes
     /// take a chain as input and return a chain.
     EH_LABEL,
 
+    /// ANNOTATION_LABEL - Represents a mid basic block label used by
+    /// annotations. This should remain within the basic block and be ordered
+    /// with respect to other call instructions, but loads and stores may float
+    /// past it.
+    ANNOTATION_LABEL,
+
     /// CATCHPAD - Represents a catchpad instruction.
     CATCHPAD,
 
     /// CATCHRET - Represents a return from a catch block funclet. Used for
     /// MSVC compatible exception handling. Takes a chain operand and a
     /// destination basic block operand.
     CATCHRET,
 

llvm/include/llvm/CodeGen/MachineFunction.h

class MachineFunction {
   std::vector<LandingPadInfo> LandingPads;
 
   /// Map a landing pad's EH symbol to the call site indexes.
   DenseMap<MCSymbol*, SmallVector<unsigned, 4>> LPadToCallSiteMap;
 
   /// Map of invoke call site index values to associated begin EH_LABEL.
   DenseMap<MCSymbol*, unsigned> CallSiteMap;
 
+  /// CodeView label annotations.
+  std::vector<std::pair<MCSymbol *, MDNode *>> CodeViewAnnotations;
+
   bool CallsEHReturn = false;
   bool CallsUnwindInit = false;
   bool HasEHFunclets = false;
 
   /// List of C++ TypeInfo used.
   std::vector<const GlobalValue *> TypeInfos;
 
   /// List of typeids encoding filters used.
unsigned getCallSiteBeginLabel(MCSymbol *BeginLabel) const {
     return CallSiteMap.lookup(BeginLabel);
   }
 
   /// Return true if the begin label has a call site number associated with it.
   bool hasCallSiteBeginLabel(MCSymbol *BeginLabel) const {
     return CallSiteMap.count(BeginLabel);
   }
 
+  /// Record annotations associated with a particular label.
+  void addCodeViewAnnotation(MCSymbol *Label, MDNode *MD) {
+    CodeViewAnnotations.push_back({Label, MD});
+  }
+
+  ArrayRef<std::pair<MCSymbol *, MDNode *>> getCodeViewAnnotations() const {
+    return CodeViewAnnotations;
+  }
+
   /// Return a reference to the C++ typeinfo for the current function.
   const std::vector<const GlobalValue *> &getTypeInfos() const {
     return TypeInfos;
   }
 
   /// Return a reference to the typeids encoding filters used in the current
   /// function.
   const std::vector<unsigned> &getFilterIds() const {

llvm/include/llvm/CodeGen/SelectionDAG.h

#endif
   SDValue getTargetExternalSymbol(const char *Sym, EVT VT,
                                   unsigned char TargetFlags = 0);
   SDValue getMCSymbol(MCSymbol *Sym, EVT VT);
 
   SDValue getValueType(EVT);
   SDValue getRegister(unsigned Reg, EVT VT);
   SDValue getRegisterMask(const uint32_t *RegMask);
   SDValue getEHLabel(const SDLoc &dl, SDValue Root, MCSymbol *Label);
+  SDValue getLabelNode(unsigned Opcode, const SDLoc &dl, SDValue Root,
+                       MCSymbol *Label);
   SDValue getBlockAddress(const BlockAddress *BA, EVT VT,
                           int64_t Offset = 0, bool isTarget = false,
                           unsigned char TargetFlags = 0);
   SDValue getTargetBlockAddress(const BlockAddress *BA, EVT VT,
                                 int64_t Offset = 0,
                                 unsigned char TargetFlags = 0) {
     return getBlockAddress(BA, VT, Offset, true, TargetFlags);
   }

llvm/include/llvm/CodeGen/SelectionDAGNodes.h

public:
   unsigned char getTargetFlags() const { return TargetFlags; }
 
   static bool classof(const SDNode *N) {
     return N->getOpcode() == ISD::BlockAddress ||
            N->getOpcode() == ISD::TargetBlockAddress;
   }
 };
 
-class EHLabelSDNode : public SDNode {
+class LabelSDNode : public SDNode {
   friend class SelectionDAG;
 
   MCSymbol *Label;
 
-  EHLabelSDNode(unsigned Order, const DebugLoc &dl, MCSymbol *L)
+  LabelSDNode(unsigned Order, const DebugLoc &dl, MCSymbol *L)
       : SDNode(ISD::EH_LABEL, Order, dl, getSDVTList(MVT::Other)), Label(L) {}
 
 public:
   MCSymbol *getLabel() const { return Label; }
 
   static bool classof(const SDNode *N) {
-    return N->getOpcode() == ISD::EH_LABEL;
+    return N->getOpcode() == ISD::EH_LABEL ||
+           N->getOpcode() == ISD::ANNOTATION_LABEL;
   }
 };
 
 class ExternalSymbolSDNode : public SDNode {
   friend class SelectionDAG;
 
   const char *Symbol;
   unsigned char TargetFlags;

llvm/include/llvm/DebugInfo/CodeView/SymbolRecord.h

public:
   TypeIndex Type;
   uint32_t DataOffset;
   uint16_t Segment;
   StringRef Name;
 
   uint32_t RecordOffset;
 };
 
+// S_ANNOTATION
+
 using CVSymbol = CVRecord<SymbolKind>;
 using CVSymbolArray = VarStreamArray<CVSymbol>;
 
 Expected<CVSymbol> readSymbolFromStream(BinaryStreamRef Stream,
                                         uint32_t Offset);
 
 } // end namespace codeview
 } // end namespace llvm
 
 #endif // LLVM_DEBUGINFO_CODEVIEW_SYMBOLRECORD_H

llvm/include/llvm/IR/Intrinsics.td

def int_ptr_annotation : Intrinsic<[LLVMAnyPointerType<llvm_anyint_ty>],
                                    [LLVMMatchType<0>, llvm_ptr_ty, llvm_ptr_ty,
                                     llvm_i32_ty],
                                    [], "llvm.ptr.annotation">;
 def int_annotation : Intrinsic<[llvm_anyint_ty],
                                [LLVMMatchType<0>, llvm_ptr_ty,
                                 llvm_ptr_ty, llvm_i32_ty],
                                [], "llvm.annotation">;
 
+// Annotates the current program point with arbitrary metadata. It is not zero
+// cost, as it is modeled as possibly reading or writing escaped memory.
+def int_codeview_annotation : Intrinsic<[], [llvm_metadata_ty], [IntrNoDuplicate],
+                                        "llvm.codeview.annotation">;
+
 //===------------------------ Trampoline Intrinsics -----------------------===//
 //
 def int_init_trampoline : Intrinsic<[],
                                     [llvm_ptr_ty, llvm_ptr_ty, llvm_ptr_ty],
                                     [IntrArgMemOnly, NoCapture<0>]>,
                                    GCCBuiltin<"__builtin_init_trampoline">;
 
 def int_adjust_trampoline : Intrinsic<[llvm_ptr_ty], [llvm_ptr_ty],

llvm/include/llvm/Target/Target.td

 }
 def GC_LABEL : Instruction {
   let OutOperandList = (outs);
   let InOperandList = (ins i32imm:$id);
   let AsmString = "";
   let hasCtrlDep = 1;
   let isNotDuplicable = 1;
 }
+def ANNOTATION_LABEL : Instruction {
+  let OutOperandList = (outs);
+  let InOperandList = (ins i32imm:$id);
+  let AsmString = "";
+  let hasCtrlDep = 1;
+  let isNotDuplicable = 1;
+}
 def KILL : Instruction {
   let OutOperandList = (outs);
   let InOperandList = (ins variable_ops);
   let AsmString = "";
   let hasSideEffects = 0;
 }
 def EXTRACT_SUBREG : Instruction {
   let OutOperandList = (outs unknown:$dst);

llvm/include/llvm/Target/TargetOpcodes.def

 
 /// Every instruction defined here must also appear in Target.td.
 ///
 HANDLE_TARGET_OPCODE(PHI)
 HANDLE_TARGET_OPCODE(INLINEASM)
 HANDLE_TARGET_OPCODE(CFI_INSTRUCTION)
 HANDLE_TARGET_OPCODE(EH_LABEL)
 HANDLE_TARGET_OPCODE(GC_LABEL)
+HANDLE_TARGET_OPCODE(ANNOTATION_LABEL)
 
 /// KILL - This instruction is a noop that is used only to adjust the
 /// liveness of registers. This can be useful when dealing with
 /// sub-registers.
 HANDLE_TARGET_OPCODE(KILL)
 
 /// EXTRACT_SUBREG - This instruction takes two operands: a register
 /// that has subregisters, and a subregister index. It returns the

llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.h

struct FunctionInfo {
     /// call sites. Listed in program order.
     std::unordered_map<const DILocation *, InlineSite> InlineSites;
 
     /// Ordered list of top-level inlined call sites.
     SmallVector<const DILocation *, 1> ChildSites;
 
     SmallVector<LocalVariable, 1> Locals;
 
+    std::vector<std::pair<MCSymbol *, MDNode *>> Annotations;
+
     const MCSymbol *Begin = nullptr;
     const MCSymbol *End = nullptr;
     unsigned FuncId = 0;
     unsigned LastFileId = 0;
     bool HaveLineInfo = false;
   };
   FunctionInfo *CurFn = nullptr;
 

llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

MCSymbol *SymbolsEnd = beginCVSubsection(DebugSubsectionKind::Symbols);
     // of their parent inline site.
     for (const DILocation *InlinedAt : FI.ChildSites) {
       auto I = FI.InlineSites.find(InlinedAt);
       assert(I != FI.InlineSites.end() &&
              "child site not in function inline site map");
       emitInlinedCallSite(FI, InlinedAt, I->second);
     }
 
+    for (auto Annot : FI.Annotations) {
+      MCSymbol *Label = Annot.first;
+      MDTuple *Strs = cast<MDTuple>(Annot.second);
+      MCSymbol *AnnotBegin = MMI->getContext().createTempSymbol(),
+               *AnnotEnd = MMI->getContext().createTempSymbol();
+      OS.AddComment("Record length");
+      OS.emitAbsoluteSymbolDiff(AnnotEnd, AnnotBegin, 2);
+      OS.EmitLabel(AnnotBegin);
+      OS.AddComment("Record kind: S_ANNOTATION");
+      OS.EmitIntValue(SymbolKind::S_ANNOTATION, 2);
+      OS.EmitCOFFSecRel32(Label, /*Offset=*/0);
+      // FIXME: Make sure we don't overflow the max record size.
+      OS.EmitCOFFSectionIndex(Label);
+      OS.EmitIntValue(Strs->getNumOperands(), 2);
+      for (Metadata *MD : Strs->operands()) {
+        // MDStrings are null terminated, so we can do EmitBytes and get the
+        // nice .asciz directive.
+        StringRef Str = cast<MDString>(MD)->getString();
+        assert(Str.data()[Str.size()] == '\0' && "non-nullterminated MDString");
+        OS.EmitBytes(StringRef(Str.data(), Str.size() + 1));
+      }
+      OS.EmitLabel(AnnotEnd);
+    }
+
     if (SP != nullptr)
       emitDebugInfoForUDTs(LocalUDTs);
 
     // We're done with this function.
     OS.AddComment("Record length");
     OS.EmitIntValue(0x0002, 2);
     OS.AddComment("Record kind: S_PROC_ID_END");
     OS.EmitIntValue(unsigned(SymbolKind::S_PROC_ID_END), 2);
void CodeViewDebug::endFunctionImpl(const MachineFunction *MF) {
 
   // Don't emit anything if we don't have any line tables.
   if (!CurFn->HaveLineInfo) {
     FnDebugInfo.erase(GV);
     CurFn = nullptr;
     return;
   }
 
+  CurFn->Annotations = MF->getCodeViewAnnotations();
+
   CurFn->End = Asm->getFunctionEnd();
 
   CurFn = nullptr;
 }
 
 void CodeViewDebug::beginInstruction(const MachineInstr *MI) {
   DebugHandlerBase::beginInstruction(MI);
 

llvm/lib/CodeGen/MachineFunction.cpp

void MachineFunction::clear() {
   //
   // Do call MachineBasicBlock destructors, it contains std::vectors.
   for (iterator I = begin(), E = end(); I != E; I = BasicBlocks.erase(I))
     I->Insts.clearAndLeakNodesUnsafely();
 
   InstructionRecycler.clear(Allocator);
   OperandRecycler.clear(Allocator);
   BasicBlockRecycler.clear(Allocator);
+  CodeViewAnnotations.clear();
   VariableDbgInfos.clear();
   if (RegInfo) {
     RegInfo->~MachineRegisterInfo();
     Allocator.Deallocate(RegInfo);
   }
   if (MFInfo) {
     MFInfo->~MachineFunctionInfo();
     Allocator.Deallocate(MFInfo);

llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp

BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TargetOpcode::COPY),
             DestReg).addReg(SrcReg);
     break;
   }
   case ISD::CopyFromReg: {
     unsigned SrcReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg();
     EmitCopyFromReg(Node, 0, IsClone, IsCloned, SrcReg, VRBaseMap);
     break;
   }
-  case ISD::EH_LABEL: {
-    MCSymbol *S = cast<EHLabelSDNode>(Node)->getLabel();
+  case ISD::EH_LABEL:
+  case ISD::ANNOTATION_LABEL: {
+    unsigned Opc = (Node->getOpcode() == ISD::EH_LABEL)
+                       ? TargetOpcode::EH_LABEL
+                       : TargetOpcode::ANNOTATION_LABEL;
+    MCSymbol *S = cast<LabelSDNode>(Node)->getLabel();
     BuildMI(*MBB, InsertPos, Node->getDebugLoc(),
-            TII->get(TargetOpcode::EH_LABEL)).addSym(S);
+            TII->get(Opc)).addSym(S);
     break;
   }
 
   case ISD::LIFETIME_START:
   case ISD::LIFETIME_END: {
     unsigned TarOp = (Node->getOpcode() == ISD::LIFETIME_START) ?
     TargetOpcode::LIFETIME_START : TargetOpcode::LIFETIME_END;
 

llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

SDValue SelectionDAG::getRegisterMask(const uint32_t *RegMask) {
   auto *N = newSDNode<RegisterMaskSDNode>(RegMask);
   CSEMap.InsertNode(N, IP);
   InsertNode(N);
   return SDValue(N, 0);
 }
 
 SDValue SelectionDAG::getEHLabel(const SDLoc &dl, SDValue Root,
                                  MCSymbol *Label) {
+  return getLabelNode(ISD::EH_LABEL, dl, Root, Label);
+}
+
+SDValue SelectionDAG::getLabelNode(unsigned Opcode, const SDLoc &dl,
+                                   SDValue Root, MCSymbol *Label) {
   FoldingSetNodeID ID;
   SDValue Ops[] = { Root };
-  AddNodeIDNode(ID, ISD::EH_LABEL, getVTList(MVT::Other), Ops);
+  AddNodeIDNode(ID, Opcode, getVTList(MVT::Other), Ops);
   ID.AddPointer(Label);
   void *IP = nullptr;
   if (SDNode *E = FindNodeOrInsertPos(ID, IP))
     return SDValue(E, 0);
 
-  auto *N = newSDNode<EHLabelSDNode>(dl.getIROrder(), dl.getDebugLoc(), Label);
+  auto *N = newSDNode<LabelSDNode>(dl.getIROrder(), dl.getDebugLoc(), Label);
   createOperands(N, Ops);
 
   CSEMap.InsertNode(N, IP);
   InsertNode(N);
   return SDValue(N, 0);
 }
 
 SDValue SelectionDAG::getBlockAddress(const BlockAddress *BA, EVT VT,

llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

case Intrinsic::invariant_group_barrier:
     // Drop the intrinsic, but forward the value
     setValue(&I, getValue(I.getOperand(0)));
     return nullptr;
   case Intrinsic::assume:
   case Intrinsic::var_annotation:
     // Discard annotate attributes and assumptions
     return nullptr;
 
+  case Intrinsic::codeview_annotation: {
+    // Emit a label associated with this metadata.
+    MachineFunction &MF = DAG.getMachineFunction();
+    MCSymbol *Label =
+        MF.getMMI().getContext().createTempSymbol("annotation", true);
+    Metadata *MD = cast<MetadataAsValue>(I.getArgOperand(0))->getMetadata();
+    MF.addCodeViewAnnotation(Label, cast<MDNode>(MD));
+    Res = DAG.getLabelNode(ISD::ANNOTATION_LABEL, sdl, getRoot(), Label);
+    DAG.setRoot(Res);
+    return nullptr;
+  }
+
   case Intrinsic::init_trampoline: {
     const Function *F = cast<Function>(I.getArgOperand(1)->stripPointerCasts());
 
     SDValue Ops[6];
     Ops[0] = getRoot();
     Ops[1] = getValue(I.getArgOperand(0));
     Ops[2] = getValue(I.getArgOperand(1));
     Ops[3] = getValue(I.getArgOperand(2));

llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp

void SelectionDAGISel::SelectCodeCommon(SDNode *NodeToMatch,
   case ISD::TargetBlockAddress:
   case ISD::TargetJumpTable:
   case ISD::TargetGlobalTLSAddress:
   case ISD::TargetGlobalAddress:
   case ISD::TokenFactor:
   case ISD::CopyFromReg:
   case ISD::CopyToReg:
   case ISD::EH_LABEL:
+  case ISD::ANNOTATION_LABEL:
   case ISD::LIFETIME_START:
   case ISD::LIFETIME_END:
     NodeToMatch->setNodeId(-1); // Mark selected.
     return;
   case ISD::AssertSext:
   case ISD::AssertZext:
     CurDAG->ReplaceAllUsesOfValueWith(SDValue(NodeToMatch, 0),
                                       NodeToMatch->getOperand(0));

llvm/test/CodeGen/X86/label-annotation.ll

+; RUN: llc < %s | FileCheck %s
+; FIXME: fastisel screws up the order here.
+; RUNX: llc -O0 < %s | FileCheck %s
+
+; Source to regenerate:
+; $ clang --target=x86_64-windows-msvc -S annotation.c  -g -gcodeview -o t.ll \
+;      -emit-llvm -O1 -Xclang -disable-llvm-passes -fms-extensions
+; void g(void);
+; void f(void) {
+;   g();
+;   __annotation(L"a1", L"a2");
+;   g();
+; }
+
+; ModuleID = 'annotation.c'
+source_filename = "annotation.c"
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc19.0.24215"
+
+; Function Attrs: nounwind uwtable
+define void @f() #0 !dbg !8 {
+entry:
+  call void @g(), !dbg !11
+  call void @llvm.codeview.annotation(metadata !12), !dbg !13
+  call void @g(), !dbg !14
+  ret void, !dbg !15
+}
+
+; CHECK-LABEL: f: # @f
+; CHECK: callq g
+; CHECK: .Lannotation0:
+; CHECK: callq g
+; CHECK: retq
+
+; CHECK-LABEL: .short  4423                    # Record kind: S_GPROC32_ID
+; CHECK:       .short  4121                    # Record kind: S_ANNOTATION
+; CHECK-NEXT:  .secrel32       .Lannotation0
+; CHECK-NEXT:  .secidx .Lannotation0
+; CHECK-NEXT:  .short  2
+; CHECK-NEXT:  .asciz  "a1"
+; CHECK-NEXT:  .asciz  "a2"
+
+; CHECK-LABEL: .short  4431                    # Record kind: S_PROC_ID_END
+
+declare void @g() #1
+
+; Function Attrs: nounwind
+declare void @llvm.codeview.annotation(metadata) #2
+
+attributes #0 = { nounwind uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #2 = { nounwind }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5, !6}
+!llvm.ident = !{!7}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 6.0.0 ", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+!1 = !DIFile(filename: "annotation.c", directory: "C:\5Csrc\5Cllvm-project\5Cbuild", checksumkind: CSK_MD5, checksum: "51164221112d8a5baa55a995027e4ba5")
+!2 = !{}
+!3 = !{i32 2, !"CodeView", i32 1}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 2}
+!6 = !{i32 7, !"PIC Level", i32 2}
+!7 = !{!"clang version 6.0.0 "}
+!8 = distinct !DISubprogram(name: "f", scope: !1, file: !1, line: 2, type: !9, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !2)
+!9 = !DISubroutineType(types: !10)
+!10 = !{null}
+!11 = !DILocation(line: 3, column: 3, scope: !8)
+!12 = !{!"a1", !"a2"}
+!13 = !DILocation(line: 4, column: 3, scope: !8)
+!14 = !DILocation(line: 5, column: 3, scope: !8)
+!15 = !DILocation(line: 6, column: 1, scope: !8)

llvm/test/Transforms/Inline/label-annotation.ll

+; Inlining should not clone label annotations.
+; Currently we block all duplication for simplicity.
+
+; RUN: opt < %s -S -inline | FileCheck %s
+
+@the_global = global i32 0
+
+declare void @llvm.codeview.annotation(metadata)
+
+define void @inlinee() {
+entry:
+  store i32 42, i32* @the_global
+  call void @llvm.codeview.annotation(metadata !0)
+  ret void
+}
+
+define void @caller() {
+entry:
+  call void @inlinee()
+  ret void
+}
+
+!0 = !{!"annotation"}
+
+; CHECK-LABEL: define void @inlinee()
+; CHECK: store i32 42, i32* @the_global
+; CHECK: call void @llvm.codeview.annotation(metadata !0)
+; CHECK: ret void
+
+; CHECK-LABEL: define void @caller()
+;       MSVC can inline this. If we ever do, check for the store but make sure
+;       there is no annotation.
+; CHECK: call void @inlinee()
+; CHECK-NOT: call void @llvm.codeview.annotation
+; CHECK: ret void