Debug info for optimized code: Support variables that are on the stack and described by DBG_VALUEs during their lifetime.

[aprantl]

Summary

Debug info for optimized code: Support variables that are on the stack and described by DBG_VALUEs during their lifetime.

Previously, when a variable was at a FrameIndex for any part of its
lifetime, this would shadow all other DBG_VALUEs and only a single
fbreg location would be emitted, which in fact is only valid for a small
range and not the entire lexical scope of the variable. The included
dbg-value-const-byref testcase demonstrates this.

This patch fixes this by
Local.cpp
- emitting dbg.value intrinsics for allocas that are passed by reference
- dropping all dbg.declares (they are now fully lowered to dbg.values)
SelectionDAG
- renamed constructors for SDDbgValue for better readability.
- fix UserValue::match() to handle indirect values correctly
- not inserting an MMI table entries for dbg.values that describe allocas.
- lowering dbg.values that describe allocas into *indirect* DBG_VALUEs.
CodeGenPrepare
- leaving dbg.values for an alloca were they are (see comment)
DwarfDebug
Other
- regenerated/updated instcombine-intrinsics testcase and included source

[echristo]

Looks like a good incremental change to get us somewhere good for debug info. OK with the typo in the comment fixed :)

lib/CodeGen/CodeGenPrepare.cpp

3057

"where"

include/llvm/CodeGen/SelectionDAG.h

 
   /// getDbgValue - Creates a SDDbgValue node.
   ///
-  SDDbgValue *getDbgValue(MDNode *MDPtr, SDNode *N, unsigned R, uint64_t Off,
-                          DebugLoc DL, unsigned O);
-  SDDbgValue *getDbgValue(MDNode *MDPtr, const Value *C, uint64_t Off,
-                          DebugLoc DL, unsigned O);
-  SDDbgValue *getDbgValue(MDNode *MDPtr, unsigned FI, uint64_t Off,
+  SDDbgValue *getDbgValue(MDNode *MDPtr, SDNode *N, unsigned R,
+        bool IsIndirect, uint64_t Off,
                           DebugLoc DL, unsigned O);
+  /// Constant.
+  SDDbgValue *getConstantDbgValue(MDNode *MDPtr, const Value *C, uint64_t Off,
+          DebugLoc DL, unsigned O);
+  /// Frame index.
+  SDDbgValue *getFrameIndexDbgValue(MDNode *MDPtr, unsigned FI, uint64_t Off,
+            DebugLoc DL, unsigned O);
 
   /// RemoveDeadNode - Remove the specified node from the system. If any of its
   /// operands then becomes dead, remove them as well. Inform UpdateListener

lib/CodeGen/CodeGenPrepare.cpp

     for (BasicBlock::iterator BI = I->begin(), BE = I->end(); BI != BE;) {
       Instruction *Insn = BI; ++BI;
       DbgValueInst *DVI = dyn_cast<DbgValueInst>(Insn);
-      if (!DVI) {
+      // Leave dbg.values that refer to an alloca alone. These
+      // instrinsics describe the address of a variable (= the alloca)
+      // being taken.  They should not be moved next to the alloca
+      // (and to the beginning of the scope), but rather stay close to
+      // were said address is used.
+      if (!DVI || (DVI->getValue() && isa<AllocaInst>(DVI->getValue()))) {
         PrevNonDbgInst = Insn;
         continue;
       }

lib/CodeGen/LiveDebugVariables.cpp

   UserValue *getNext() const { return next; }
 
   /// match - Does this UserValue match the parameters?
-  bool match(const MDNode *Var, unsigned Offset) const {
-    return Var == variable && Offset == offset;
+  bool match(const MDNode *Var, unsigned Offset, bool indirect) const {
+    return Var == variable && Offset == offset && indirect == IsIndirect;
   }
 
   /// merge - Merge equivalence classes.

     UserValue *UV = Leader->getLeader();
     Leader = UV;
     for (; UV; UV = UV->getNext())
-      if (UV->match(Var, Offset))
+      if (UV->match(Var, Offset, IsIndirect))
         return UV;
   }
 

lib/CodeGen/SelectionDAG/InstrEmitter.cpp

     MIB.addReg(0U);
   }
 
-  if (Offset != 0) // Indirect addressing.
+  // Indirect addressing is indicated by an Imm as the second parameter.
+  if (SD->isIndirect())
     MIB.addImm(Offset);
-  else
+  else {
+    assert(Offset == 0 && "direct value cannot have an offset");
     MIB.addReg(0U, RegState::Debug);
+  }
 
   MIB.addMetadata(MDPtr);
 

lib/CodeGen/SelectionDAG/SDNodeDbgValue.h

     unsigned FrameIx;       // valid for stack objects
   } u;
   MDNode *mdPtr;
+  bool IsIndirect;
   uint64_t Offset;
   DebugLoc DL;
   unsigned Order;
   bool Invalid;
 public:
   // Constructor for non-constants.
-  SDDbgValue(MDNode *mdP, SDNode *N, unsigned R, uint64_t off, DebugLoc dl,
-             unsigned O) : mdPtr(mdP), Offset(off), DL(dl), Order(O),
+  SDDbgValue(MDNode *mdP, SDNode *N, unsigned R,
+       bool indir, uint64_t off, DebugLoc dl,
+             unsigned O) : mdPtr(mdP), IsIndirect(indir),
+         Offset(off), DL(dl), Order(O),
                            Invalid(false) {
     kind = SDNODE;
     u.s.Node = N;

   // Constructor for constants.
   SDDbgValue(MDNode *mdP, const Value *C, uint64_t off, DebugLoc dl,
              unsigned O) : 
-    mdPtr(mdP), Offset(off), DL(dl), Order(O), Invalid(false) {
+    mdPtr(mdP), IsIndirect(false), Offset(off), DL(dl), Order(O),
+    Invalid(false) {
     kind = CONST;
     u.Const = C;
   }
 
   // Constructor for frame indices.
   SDDbgValue(MDNode *mdP, unsigned FI, uint64_t off, DebugLoc dl, unsigned O) : 
-    mdPtr(mdP), Offset(off), DL(dl), Order(O), Invalid(false) {
+    mdPtr(mdP), IsIndirect(false), Offset(off), DL(dl), Order(O),
+    Invalid(false) {
     kind = FRAMEIX;
     u.FrameIx = FI;
   }

   // Returns the FrameIx for a stack object
   unsigned getFrameIx() { assert (kind==FRAMEIX); return u.FrameIx; }
 
+  // Returns whether this is an indirect value.
+  bool isIndirect() { return IsIndirect; }
+
   // Returns the offset.
   uint64_t getOffset() { return Offset; }
 

lib/CodeGen/SelectionDAG/SelectionDAG.cpp

 
 /// getDbgValue - Creates a SDDbgValue node.
 ///
+/// SDNode
 SDDbgValue *
-SelectionDAG::getDbgValue(MDNode *MDPtr, SDNode *N, unsigned R, uint64_t Off,
+SelectionDAG::getDbgValue(MDNode *MDPtr, SDNode *N, unsigned R,
+        bool IsIndirect, uint64_t Off,
                           DebugLoc DL, unsigned O) {
-  return new (Allocator) SDDbgValue(MDPtr, N, R, Off, DL, O);
+  return new (Allocator) SDDbgValue(MDPtr, N, R, IsIndirect, Off, DL, O);
 }
 
+/// Constant
 SDDbgValue *
-SelectionDAG::getDbgValue(MDNode *MDPtr, const Value *C, uint64_t Off,
-                          DebugLoc DL, unsigned O) {
+SelectionDAG::getConstantDbgValue(MDNode *MDPtr, const Value *C,
+          uint64_t Off,
+          DebugLoc DL, unsigned O) {
   return new (Allocator) SDDbgValue(MDPtr, C, Off, DL, O);
 }
 
+/// FrameIndex
 SDDbgValue *
-SelectionDAG::getDbgValue(MDNode *MDPtr, unsigned FI, uint64_t Off,
-                          DebugLoc DL, unsigned O) {
+SelectionDAG::getFrameIndexDbgValue(MDNode *MDPtr, unsigned FI, uint64_t Off,
+            DebugLoc DL, unsigned O) {
   return new (Allocator) SDDbgValue(MDPtr, FI, Off, DL, O);
 }
 

     SDDbgValue *Dbg = *I;
     if (Dbg->getKind() == SDDbgValue::SDNODE) {
       SDDbgValue *Clone = getDbgValue(Dbg->getMDPtr(), ToNode, To.getResNo(),
+              Dbg->isIndirect(),
                                       Dbg->getOffset(), Dbg->getDebugLoc(),
                                       Dbg->getOrder());
       ClonedDVs.push_back(Clone);

lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

     unsigned DbgSDNodeOrder = DDI.getSDNodeOrder();
     MDNode *Variable = DI->getVariable();
     uint64_t Offset = DI->getOffset();
+    // FIXME: This does not handle indirect values at offset 0.
+    bool IsIndirect = (Offset != 0);
     SDDbgValue *SDV;
     if (Val.getNode()) {
       if (!EmitFuncArgumentDbgValue(V, Variable, Offset, Val)) {
         SDV = DAG.getDbgValue(Variable, Val.getNode(),
-                              Val.getResNo(), Offset, dl, DbgSDNodeOrder);
+                              Val.getResNo(), IsIndirect,
+            Offset, dl, DbgSDNodeOrder);
         DAG.AddDbgValue(SDV, Val.getNode(), false);
       }
     } else

         FrameIndexSDNode *FINode = dyn_cast<FrameIndexSDNode>(N.getNode());
         if (FINode)
           // Byval parameter.  We have a frame index at this point.
-          SDV = DAG.getDbgValue(Variable, FINode->getIndex(),
-                                0, dl, SDNodeOrder);
+          SDV = DAG.getFrameIndexDbgValue(Variable, FINode->getIndex(),
+            0, dl, SDNodeOrder);
         else {
           // Address is an argument, so try to emit its dbg value using
           // virtual register info from the FuncInfo.ValueMap.

         }
       } else if (AI)
         SDV = DAG.getDbgValue(Variable, N.getNode(), N.getResNo(),
-                              0, dl, SDNodeOrder);
+                              true, 0, dl, SDNodeOrder);
       else {
         // Can't do anything with other non-AI cases yet.
         DEBUG(dbgs() << "Dropping debug info for " << DI << "\n");

             DenseMap<const AllocaInst*, int>::iterator SI =
               FuncInfo.StaticAllocaMap.find(AI);
             if (SI != FuncInfo.StaticAllocaMap.end()) {
-              SDV = DAG.getDbgValue(Variable, SI->second,
+              SDV = DAG.getFrameIndexDbgValue(Variable, SI->second,
                                               0, dl, SDNodeOrder);
               DAG.AddDbgValue(SDV, nullptr, false);
               return nullptr;
             }

 
     SDDbgValue *SDV;
     if (isa<ConstantInt>(V) || isa<ConstantFP>(V) || isa<UndefValue>(V)) {
-      SDV = DAG.getDbgValue(Variable, V, Offset, dl, SDNodeOrder);
+      SDV = DAG.getConstantDbgValue(Variable, V, Offset, dl, SDNodeOrder);
       DAG.AddDbgValue(SDV, nullptr, false);
     } else {
       // Do not use getValue() in here; we don't want to generate code at

         N = UnusedArgNodeMap[V];
       if (N.getNode()) {
         if (!EmitFuncArgumentDbgValue(V, Variable, Offset, N)) {
+    // A dbg.value for an alloca is always indirect.
+    bool IsIndirect(isa<AllocaInst>(V));
           SDV = DAG.getDbgValue(Variable, N.getNode(),
-                                N.getResNo(), Offset, dl, SDNodeOrder);
+                                N.getResNo(), IsIndirect,
+        Offset, dl, SDNodeOrder);
           DAG.AddDbgValue(SDV, N.getNode(), false);
         }
       } else if (!V->use_empty() ) {

       FuncInfo.StaticAllocaMap.find(AI);
     if (SI == FuncInfo.StaticAllocaMap.end())
       return nullptr; // VLAs.
-    int FI = SI->second;
-
-    MachineModuleInfo &MMI = DAG.getMachineFunction().getMMI();
-    if (!DI.getDebugLoc().isUnknown() && MMI.hasDebugInfo())
-      MMI.setVariableDbgInfo(Variable, FI, DI.getDebugLoc());
     return nullptr;
   }
 

lib/Transforms/Utils/Local.cpp

     AllocaInst *AI = dyn_cast_or_null<AllocaInst>(DDI->getAddress());
     // If this is an alloca for a scalar variable, insert a dbg.value
     // at each load and store to the alloca and erase the dbg.declare.
+    // The dbg.values allow tracking a variable even if it is not
+    // stored on the stack, while the dbg.declare can only describe
+    // the stack slot (and at a lexical-scope granularity). Later
+    // passes will attempt to elide the stack slot.
     if (AI && !AI->isArrayAllocation()) {
-
-      // We only remove the dbg.declare intrinsic if all uses are
-      // converted to dbg.value intrinsics.
-      bool RemoveDDI = true;
       for (User *U : AI->users())
         if (StoreInst *SI = dyn_cast<StoreInst>(U))
           ConvertDebugDeclareToDebugValue(DDI, SI, DIB);
         else if (LoadInst *LI = dyn_cast<LoadInst>(U))
           ConvertDebugDeclareToDebugValue(DDI, LI, DIB);
-        else
-          RemoveDDI = false;
-      if (RemoveDDI)
-        DDI->eraseFromParent();
+        else if (Instruction *I = dyn_cast<Instruction>(U)) {
+    // This is a call by-value or some other instruction that
+    // takes a pointer to the variable. Insert a *value*
+    // intrinsic that describes the alloca.
+    auto DbgVal =
+      DIB.insertDbgValueIntrinsic(AI, 0,
+          DIVariable(DDI->getVariable()), I);
+    DbgVal->setDebugLoc(I->getDebugLoc());
+  }
+      DDI->eraseFromParent();
     }
   }
   return true;

test/DebugInfo/X86/dbg-value-const-byref.ll

 ; CHECK: Beginning address offset: [[C2]]
 ; CHECK:    Ending address offset: [[R1:.*]]
 ; CHECK:     Location description: 50 93 04
+;         rdi+0
+; CHECK: Beginning address offset: [[R1]]
+; CHECK:    Ending address offset: [[R2:.*]]
+; CHECK:     Location description: 75 00 
 ;
 target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-apple-macosx10.9.0"

   %call1 = call i32 (...)* @f1() #3, !dbg !19
   call void @llvm.dbg.value(metadata !{i32 %call1}, i64 0, metadata !10), !dbg !19
   store i32 %call1, i32* %i, align 4, !dbg !19, !tbaa !20
+  call void @llvm.dbg.value(metadata !{i32* %i}, i64 0, metadata !10), !dbg !24
   call void @f2(i32* %i) #3, !dbg !24
   ret i32 0, !dbg !25
 }

test/DebugInfo/X86/instcombine-instrinsics.ll

-; RUN: opt < %s -O2 -S | FileCheck %s
+; RUN: opt %s -O2 -S -o - | FileCheck %s
 ; Verify that we emit the same intrinsic at most once.
-; CHECK: call void @llvm.dbg.value(metadata !{%struct.i14** %i14}
-; CHECK-NOT: call void @llvm.dbg.value(metadata !{%struct.i14** %i14}
+; rdar://problem/13056109
+;
+; CHECK: call void @llvm.dbg.value(metadata !{%struct.i14** %p}
+; CHECK-NOT: call void @llvm.dbg.value(metadata !{%struct.i14** %p}
+; CHECK-NEXT: call i32 @foo
 ; CHECK: ret
-
-;*** IR Dump After Dead Argument Elimination ***
-target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
-target triple = "x86_64-apple-macosx10.8.0"
-
-%struct.i3 = type { i32 }
-%struct.i14 = type { i32 }
-%struct.i24 = type opaque
-
-define %struct.i3* @barz(i64 %i9) nounwind {
-entry:
-  br label %while.cond
-
-while.cond:                                       ; preds = %while.body, %entry
-  br label %while.body
-
-while.body:                                       ; preds = %while.cond
-  br label %while.cond
-}
-
-declare void @llvm.dbg.declare(metadata, metadata)
-
-define void @init() nounwind {
-entry:
-  %i14 = alloca %struct.i14*, align 8
-  call void @llvm.dbg.declare(metadata !{%struct.i14** %i14}, metadata !25)
-  store %struct.i14* null, %struct.i14** %i14, align 8
-  %call = call i32 @foo(i8* bitcast (void ()* @bar to i8*), %struct.i14** %i14)
-  %0 = load %struct.i14** %i14, align 8
-  %i16 = getelementptr inbounds %struct.i14* %0, i32 0, i32 0
-  %1 = load i32* %i16, align 4
-  %or = or i32 %1, 4
-  store i32 %or, i32* %i16, align 4
-  %call4 = call i32 @foo(i8* bitcast (void ()* @baz to i8*), %struct.i14** %i14)
-  ret void
+;
+;
+; typedef struct {
+;   long i;
+; } i14;
+;
+; int foo(i14**);
+;
+;   void init() {
+;     i14* p = 0;
+;     foo(&p);
+;     p->i |= 4;
+;     foo(&p);
+;   }
+;
+; ModuleID = 'instcombine_intrinsics.c'
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.9.0"
+
+%struct.i14 = type { i64 }
+
+; Function Attrs: nounwind ssp uwtable
+define void @init() #0 {
+  %p = alloca %struct.i14*, align 8
+  call void @llvm.dbg.declare(metadata !{%struct.i14** %p}, metadata !11), !dbg !18
+  store %struct.i14* null, %struct.i14** %p, align 8, !dbg !18
+  %1 = call i32 @foo(%struct.i14** %p), !dbg !19
+  %2 = load %struct.i14** %p, align 8, !dbg !20
+  %3 = getelementptr inbounds %struct.i14* %2, i32 0, i32 0, !dbg !20
+  %4 = load i64* %3, align 8, !dbg !20
+  %5 = or i64 %4, 4, !dbg !20
+  store i64 %5, i64* %3, align 8, !dbg !20
+  %6 = call i32 @foo(%struct.i14** %p), !dbg !21
+  ret void, !dbg !22
 }
 
-declare i32 @foo(i8*, %struct.i14**) nounwind
-
-define internal void @bar() nounwind {
-entry:
-  %i9 = alloca i64, align 8
-  store i64 0, i64* %i9, align 8
-  %call = call i32 @put(i64 0, i64* %i9, i64 0, %struct.i24* null)
-  ret void
-}
-
-define internal void @baz() nounwind {
-entry:
-  ret void
-}
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.declare(metadata, metadata) #1
 
-declare i32 @put(i64, i64*, i64, %struct.i24*) nounwind readnone
+declare i32 @foo(%struct.i14**)
 
-declare void @llvm.dbg.value(metadata, i64, metadata) nounwind readnone
+attributes #0 = { nounwind ssp uwtable }
+attributes #1 = { nounwind readnone }
 
 !llvm.dbg.cu = !{!0}
-!llvm.module.flags = !{!73}
+!llvm.module.flags = !{!8, !9}
+!llvm.ident = !{!10}
 
-!0 = metadata !{i32 786449, metadata !1, i32 12, metadata !"clang version 3.3 ", i1 true, metadata !"", i32 0, metadata !2, metadata !2, metadata !3, metadata !48, null, metadata !""} ; [ DW_TAG_compile_unit ]
-!1 = metadata !{metadata !"i1", metadata !""}
-!2 = metadata !{i32 0}
-!3 = metadata !{metadata !4, metadata !21, metadata !33, metadata !47}
-!4 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"i2", metadata !"i2", metadata !"", i32 31, metadata !6, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 true, %struct.i3* (i64)* @barz, null, null, metadata !16, i32 32} ; [ DW_TAG_subprogram ] [line 31]  [scope 32]
-!5 = metadata !{i32 786473, metadata !1}          ; [ DW_TAG_file_type ]
+!0 = metadata !{i32 786449, metadata !1, i32 12, metadata !"clang version 3.5.0 ", i1 false, metadata !"", i32 0, metadata !2, metadata !2, metadata !3, metadata !2, metadata !2, metadata !"", i32 1} ; [ DW_TAG_compile_unit ] [instcombine_intrinsics.c] [DW_LANG_C99]
+!1 = metadata !{metadata !"instcombine_intrinsics.c", metadata !""}
+!2 = metadata !{}
+!3 = metadata !{metadata !4}
+!4 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"init", metadata !"init", metadata !"", i32 7, metadata !6, i1 false, i1 true, i32 0, i32 0, null, i32 0, i1 false, void ()* @init, null, null, metadata !2, i32 7} ; [ DW_TAG_subprogram ] [line 7] [def] [init]
+!5 = metadata !{i32 786473, metadata !1}          ; [ DW_TAG_file_type ] [instcombine_intrinsics.c]
 !6 = metadata !{i32 786453, i32 0, null, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !7, i32 0, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
-!7 = metadata !{metadata !8, metadata !13}
-!8 = metadata !{i32 786447, null, null, metadata !"", i32 0, i64 64, i64 64, i64 0, i32 0, metadata !9} ; [ DW_TAG_pointer_type ] [line 0, size 64, align 64, offset 0] [from i3]
-!9 = metadata !{i32 786451, metadata !1, null, metadata !"i3", i32 25, i64 32, i64 32, i32 0, i32 0, null, metadata !10, i32 0, null, null, null} ; [ DW_TAG_structure_type ] [i3] [line 25, size 32, align 32, offset 0] [def] [from ]
-!10 = metadata !{metadata !11}
-!11 = metadata !{i32 786445, metadata !1, metadata !9, metadata !"i4", i32 26, i64 32, i64 32, i64 0, i32 0, metadata !12} ; [ DW_TAG_member ]  [line 26, size 32, align 32, offset 0] [from i5]
-!12 = metadata !{i32 786468, null, null, metadata !"i5", i32 0, i64 32, i64 32, i64 0, i32 0, i32 7} ; [ DW_TAG_base_type ]  [line 0, size 32, align 32, offset 0, enc DW_ATE_unsigned]
-!13 = metadata !{i32 786454, metadata !1, null, metadata !"i6", i32 5, i64 0, i64 0, i64 0, i32 0, metadata !14} ; [ DW_TAG_typedef ]  [line 5, size 0, align 0, offset 0] [from i7]
-!14 = metadata !{i32 786454, metadata !1, null, metadata !"i7", i32 2, i64 0, i64 0, i64 0, i32 0, metadata !15} ; [ DW_TAG_typedef ]  [line 2, size 0, align 0, offset 0] [from i8]
-!15 = metadata !{i32 786468, null, null, metadata !"i8", i32 0, i64 64, i64 64, i64 0, i32 0, i32 7} ; [ DW_TAG_base_type ]  [line 0, size 64, align 64, offset 0, enc DW_ATE_unsigned]
-!16 = metadata !{}
-!21 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"i13", metadata !"i13", metadata !"", i32 42, metadata !22, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 true, void ()* @init, null, null, metadata !24, i32 43} ; [ DW_TAG_subprogram ] [line 42]  [scope 43]
-!22 = metadata !{i32 786453, i32 0, null, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !34, i32 0, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
-!23 = metadata !{null}
-!24 = metadata !{metadata !25}
-!25 = metadata !{i32 786688, metadata !21, metadata !"i14", metadata !5, i32 45, metadata !27, i32 0, i32 0} ; [ DW_TAG_auto_variable ]  [line 45]
-!27 = metadata !{i32 786447, null, null, metadata !"", i32 0, i64 64, i64 64, i64 0, i32 0, metadata !28} ; [ DW_TAG_pointer_type ] [line 0, size 64, align 64, offset 0] [from i14]
-!28 = metadata !{i32 786451, metadata !1, null, metadata !"i14", i32 16, i64 32, i64 32, i32 0, i32 0, null, metadata !29, i32 0, null, null, null} ; [ DW_TAG_structure_type ] [i14] [line 16, size 32, align 32, offset 0] [def] [from ]
-!29 = metadata !{metadata !30}
-!30 = metadata !{i32 786445, metadata !1, metadata !28, metadata !"i16", i32 17, i64 32, i64 32, i64 0, i32 0, metadata !31} ; [ DW_TAG_member ]  [line 17, size 32, align 32, offset 0] [from i17]
-!31 = metadata !{i32 786454, metadata !1, null, metadata !"i17", i32 7, i64 0, i64 0, i64 0, i32 0, metadata !32} ; [ DW_TAG_typedef ]  [line 7, size 0, align 0, offset 0] [from int]
-!32 = metadata !{i32 786468, null, null, metadata !"int", i32 0, i64 32, i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ]  [line 0, size 32, align 32, offset 0, enc DW_ATE_signed]
-!33 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"i18", metadata !"i18", metadata !"", i32 54, metadata !22, i1 true, i1 true, i32 0, i32 0, null, i32 256, i1 true, void ()* @bar, null, null, metadata !34, i32 55} ; [ DW_TAG_subprogram ] [line 54]   [scope 55]
-!34 = metadata !{null}
-!47 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"i29", metadata !"i29", metadata !"", i32 53, metadata !22, i1 true, i1 true, i32 0, i32 0, null, i32 256, i1 true, void ()* @baz, null, null, metadata !2, i32 53} ; [ DW_TAG_subprogram ] [line 53]
-!48 = metadata !{metadata !49}
-!49 = metadata !{i32 786484, i32 0, metadata !21, metadata !"i30", metadata !"i30", metadata !"", metadata !5, i32 44, metadata !50, i32 1, i32 1, null, null}
-!50 = metadata !{i32 786454, metadata !1, null, metadata !"i31", i32 6, i64 0, i64 0, i64 0, i32 0, metadata !32} ; [ DW_TAG_typedef ]  [line 6, size 0, align 0, offset 0] [from int]
-!52 = metadata !{i64 0}
-!55 = metadata !{%struct.i3* null}
-!72 = metadata !{%struct.i24* null}
-!73 = metadata !{i32 1, metadata !"Debug Info Version", i32 1}
+!7 = metadata !{null}
+!8 = metadata !{i32 2, metadata !"Dwarf Version", i32 2}
+!9 = metadata !{i32 1, metadata !"Debug Info Version", i32 1}
+!10 = metadata !{metadata !"clang version 3.5.0 "}
+!11 = metadata !{i32 786688, metadata !4, metadata !"p", metadata !5, i32 8, metadata !12, i32 0, i32 0} ; [ DW_TAG_auto_variable ] [p] [line 8]
+!12 = metadata !{i32 786447, null, null, metadata !"", i32 0, i64 64, i64 64, i64 0, i32 0, metadata !13} ; [ DW_TAG_pointer_type ] [line 0, size 64, align 64, offset 0] [from i14]
+!13 = metadata !{i32 786454, metadata !1, null, metadata !"i14", i32 3, i64 0, i64 0, i64 0, i32 0, metadata !14} ; [ DW_TAG_typedef ] [i14] [line 3, size 0, align 0, offset 0] [from ]
+!14 = metadata !{i32 786451, metadata !1, null, metadata !"", i32 1, i64 64, i64 64, i32 0, i32 0, null, metadata !15, i32 0, null, null, null} ; [ DW_TAG_structure_type ] [line 1, size 64, align 64, offset 0] [def] [from ]
+!15 = metadata !{metadata !16}
+!16 = metadata !{i32 786445, metadata !1, metadata !14, metadata !"i", i32 2, i64 64, i64 64, i64 0, i32 0, metadata !17} ; [ DW_TAG_member ] [i] [line 2, size 64, align 64, offset 0] [from long int]
+!17 = metadata !{i32 786468, null, null, metadata !"long int", i32 0, i64 64, i64 64, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ] [long int] [line 0, size 64, align 64, offset 0, enc DW_ATE_signed]
+!18 = metadata !{i32 8, i32 0, metadata !4, null} ; [ DW_TAG_imported_declaration ]
+!19 = metadata !{i32 9, i32 0, metadata !4, null}
+!20 = metadata !{i32 10, i32 0, metadata !4, null}
+!21 = metadata !{i32 11, i32 0, metadata !4, null}
+!22 = metadata !{i32 12, i32 0, metadata !4, null}