[DWARF] Fix debug info generation for function static variables, typedefs, and records

Function static variables, typedefs and records (class, struct or union) declared inside
a lexical scope were associated with the function as their parent scope, rather than the
lexical scope they are defined or declared in.

This fixes PR19238

Patch by: amjad.aboud@intel.com
Differential Revision: http://reviews.llvm.org/D9758

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241153 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/ADT/iterator_range.h

@@ -53,4 +53,7 @@ template <typename T> iterator_range<T> make_range(std::pair<T, T> p) {
 }
 }
 
+template <typename R>
+bool empty(const R& r) { return begin(r) == end(r); }
+
 #endif

lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp

@@ -101,7 +101,7 @@ static const ConstantExpr *getMergedGlobalExpr(const Value *V) {
 
 /// getOrCreateGlobalVariableDIE - get or create global variable DIE.
 DIE *DwarfCompileUnit::getOrCreateGlobalVariableDIE(
-    const DIGlobalVariable *GV) {
+  const DIGlobalVariable *GV, DIE *ContextDIE) {
   // Check for pre-existence.
   if (DIE *Die = getDIE(GV))
     return Die;
@@ -113,7 +113,8 @@ DIE *DwarfCompileUnit::getOrCreateGlobalVariableDIE(
 
   // Construct the context before querying for the existence of the DIE in
   // case such construction creates the DIE.
-  DIE *ContextDIE = getOrCreateContextDIE(GVContext);
+  if (ContextDIE == nullptr)
+    ContextDIE = getOrCreateContextDIE(GVContext);
 
   // Add to map.
   DIE *VariableDIE = &createAndAddDIE(GV->getTag(), *ContextDIE, GV);
@@ -335,17 +336,16 @@ void DwarfCompileUnit::constructScopeDIE(
     // null and the children will be added to the scope DIE.
     createScopeChildrenDIE(Scope, Children, &ChildScopeCount);
 
-    // Skip imported directives in gmlt-like data.
-    if (!includeMinimalInlineScopes()) {
-      // There is no need to emit empty lexical block DIE.
-      for (const auto &E : DD->findImportedEntitiesForScope(DS))
-        Children.push_back(
-            constructImportedEntityDIE(cast<DIImportedEntity>(E.second)));
-    }
+
+    DwarfDebug::LocalDeclMapRange LocalDeclNodeRangeForScope(nullptr, nullptr);
+    // Skip local decls in gmlt-like data.
+    if (!includeMinimalInlineScopes())
+      LocalDeclNodeRangeForScope = DD->findLocalDeclNodesForScope(DS);
 
     // If there are only other scopes as children, put them directly in the
     // parent instead, as this scope would serve no purpose.
-    if (Children.size() == ChildScopeCount) {
+    if (Children.size() == ChildScopeCount &&
+        empty(LocalDeclNodeRangeForScope)) {
       FinalChildren.insert(FinalChildren.end(),
                            std::make_move_iterator(Children.begin()),
                            std::make_move_iterator(Children.end()));
@@ -353,6 +353,15 @@ void DwarfCompileUnit::constructScopeDIE(
     }
     ScopeDIE = constructLexicalScopeDIE(Scope);
     assert(ScopeDIE && "Scope DIE should not be null.");
+
+    for (const auto &DI : LocalDeclNodeRangeForScope) {
+      if (auto *IE = dyn_cast<DIImportedEntity>(DI.second))
+        Children.push_back(constructImportedEntityDIE(IE));
+      else if (auto *GV = dyn_cast<DIGlobalVariable>(DI.second))
+        getOrCreateGlobalVariableDIE(GV, ScopeDIE);
+      else if (auto *RT = dyn_cast<DIType>(DI.second))
+        getOrCreateTypeDIE(RT, ScopeDIE);
+    }
   }
 
   // Add children

lib/CodeGen/AsmPrinter/DwarfCompileUnit.h

@@ -77,8 +77,11 @@ public:
   /// Apply the DW_AT_stmt_list from this compile unit to the specified DIE.
   void applyStmtList(DIE &D);
 
-  /// getOrCreateGlobalVariableDIE - get or create global variable DIE.
-  DIE *getOrCreateGlobalVariableDIE(const DIGlobalVariable *GV);
+  /// Get or create global variable DIE.
+  /// \param GV Global Variable Node
+  /// \param ContextDIE DIE scope for GV Node, if available.
+  DIE *getOrCreateGlobalVariableDIE(const DIGlobalVariable *GV,
+                                    DIE *ContextDIE = nullptr);
 
   /// addLabelAddress - Add a dwarf label attribute data and value using
   /// either DW_FORM_addr or DW_FORM_GNU_addr_index.

lib/CodeGen/AsmPrinter/DwarfDebug.cpp

@@ -449,14 +449,14 @@ void DwarfDebug::beginModule() {
     auto *CUNode = cast<DICompileUnit>(N);
     DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
     for (auto *IE : CUNode->getImportedEntities())
-      ScopesWithImportedEntities.push_back(std::make_pair(IE->getScope(), IE));
-    // Stable sort to preserve the order of appearance of imported entities.
-    // This is to avoid out-of-order processing of interdependent declarations
-    // within the same scope, e.g. { namespace A = base; namespace B = A; }
-    std::stable_sort(ScopesWithImportedEntities.begin(),
-                     ScopesWithImportedEntities.end(), less_first());
-    for (auto *GV : CUNode->getGlobalVariables())
+      ScopesWithLocalDeclNodes.push_back(std::make_pair(IE->getScope(), IE));
+    for (auto *GV : CUNode->getGlobalVariables()) {
+      auto *Context = GV->getScope();
+      if (Context && isa<DILexicalBlockBase>(Context))
+        ScopesWithLocalDeclNodes.push_back(std::make_pair(Context, GV));
+      else
         CU.getOrCreateGlobalVariableDIE(GV);
+    }
     for (auto *SP : CUNode->getSubprograms())
       SPMap.insert(std::make_pair(SP, &CU));
     for (auto *Ty : CUNode->getEnumTypes()) {
@@ -467,12 +467,23 @@ void DwarfDebug::beginModule() {
     for (auto *Ty : CUNode->getRetainedTypes()) {
       // The retained types array by design contains pointers to
       // MDNodes rather than DIRefs. Unique them here.
-      CU.getOrCreateTypeDIE(cast<DIType>(resolve(Ty->getRef())));
+      DIType *RT = cast<DIType>(resolve(Ty->getRef()));
+      auto *Context = resolve(Ty->getScope());
+      if (Context && isa<DILexicalBlockBase>(Context))
+        ScopesWithLocalDeclNodes.push_back(std::make_pair(Context, RT));
+      else
+        CU.getOrCreateTypeDIE(RT);
     }
     // Emit imported_modules last so that the relevant context is already
     // available.
     for (auto *IE : CUNode->getImportedEntities())
       constructAndAddImportedEntityDIE(CU, IE);
+
+    // Stable sort to preserve the order of appearance of imported entities.
+    // This is to avoid out-of-order processing of interdependent declarations
+    // within the same scope, e.g. { namespace A = base; namespace B = A; }
+    std::stable_sort(ScopesWithLocalDeclNodes.begin(),
+                     ScopesWithLocalDeclNodes.end(), less_first());
   }
 
   // Tell MMI that we have debug info.

lib/CodeGen/AsmPrinter/DwarfDebug.h

@@ -278,13 +278,10 @@ class DwarfDebug : public AsmPrinterHandler {
   // Holder for the file specific debug information.
   DwarfFile InfoHolder;
 
-  // Holders for the various debug information flags that we might need to
-  // have exposed. See accessor functions below for description.
-
-  // Holder for imported entities.
+  // Holder for local declaration DI nodes per scope.
   typedef SmallVector<std::pair<const MDNode *, const MDNode *>, 32>
-  ImportedEntityMap;
-  ImportedEntityMap ScopesWithImportedEntities;
+  LocalDeclMap;
+  LocalDeclMap ScopesWithLocalDeclNodes;
 
   // Map from MDNodes for user-defined types to the type units that describe
   // them.
@@ -619,10 +616,12 @@ public:
 
   const MachineFunction *getCurrentFunction() const { return CurFn; }
 
-  iterator_range<ImportedEntityMap::const_iterator>
-  findImportedEntitiesForScope(const MDNode *Scope) const {
+  typedef iterator_range<LocalDeclMap::const_iterator> LocalDeclMapRange;
+  
+  LocalDeclMapRange findLocalDeclNodesForScope(const MDNode *Scope) const {
+    assert(DILexicalBlockBase::classof(Scope) && "Expected LexicalBlock scope");
     return make_range(std::equal_range(
-        ScopesWithImportedEntities.begin(), ScopesWithImportedEntities.end(),
+        ScopesWithLocalDeclNodes.begin(), ScopesWithLocalDeclNodes.end(),
         std::pair<const MDNode *, const MDNode *>(Scope, nullptr),
         less_first()));
   }

lib/CodeGen/AsmPrinter/DwarfUnit.cpp

@@ -704,7 +704,7 @@ DIE *DwarfUnit::createTypeDIE(const DICompositeType *Ty) {
   return &TyDIE;
 }
 
-DIE *DwarfUnit::getOrCreateTypeDIE(const MDNode *TyNode) {
+DIE *DwarfUnit::getOrCreateTypeDIE(const MDNode *TyNode, DIE *ContextDIE) {
   if (!TyNode)
     return nullptr;
 
@@ -714,17 +714,20 @@ DIE *DwarfUnit::getOrCreateTypeDIE(const MDNode *TyNode) {
 
   // DW_TAG_restrict_type is not supported in DWARF2
   if (Ty->getTag() == dwarf::DW_TAG_restrict_type && DD->getDwarfVersion() <= 2)
-    return getOrCreateTypeDIE(resolve(cast<DIDerivedType>(Ty)->getBaseType()));
+    return getOrCreateTypeDIE(resolve(cast<DIDerivedType>(Ty)->getBaseType()),
+                              ContextDIE);
 
   // Construct the context before querying for the existence of the DIE in case
   // such construction creates the DIE.
   auto *Context = resolve(Ty->getScope());
-  DIE *ContextDIE = getOrCreateContextDIE(Context);
-  assert(ContextDIE);
+  if (ContextDIE == nullptr)
+    ContextDIE = getOrCreateContextDIE(Context);
 
   if (DIE *TyDIE = getDIE(Ty))
     return TyDIE;
 
+  assert(ContextDIE);
+
   // Create new type.
   DIE &TyDIE = createAndAddDIE(Ty->getTag(), *ContextDIE, Ty);
 

lib/CodeGen/AsmPrinter/DwarfUnit.h

@@ -298,7 +298,9 @@ public:
                                  bool Minimal = false);
 
   /// \brief Find existing DIE or create new DIE for the given type.
-  DIE *getOrCreateTypeDIE(const MDNode *N);
+  /// \param N Type Node
+  /// \param ContextDIE DIE scope for N Node, if available.
+  DIE *getOrCreateTypeDIE(const MDNode *N, DIE *ContextDIE = nullptr);
 
   /// \brief Get context owner's DIE.
   DIE *createTypeDIE(const DICompositeType *Ty);

test/DebugInfo/lexical-block.ll

@@ -0,0 +1,129 @@
+; RUN: llc -mtriple=x86_64-unknown-linux-gnu -filetype=obj -O0 < %s  | llvm-dwarfdump -debug-dump=info - | FileCheck %s
+
+;; This test checks the following:
+;; 1. Useless lexical block entry is not emitted
+;; 2. Function static variable, typedef, records (structure, class and union)
+;;    that are defined in lexical basic block are emitted as children to
+;;    these lexical blocks.
+;;    * For typedef and record check that both are emitted in lexical block
+;;      where they are declared and not in the one where they are used.
+;;
+;; This test was generated by running following command:
+;; clang -cc1 -O0 -g -emit-llvm foo.cpp 
+;; Where foo.cpp
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;int foo(void) { 
+;;  {
+;;    {
+;;      struct X {
+;;        int x;
+;;      };
+;;      typedef int Y;
+;;      {
+;;        X a;
+;;        Y b;
+;;        static int c;
+;;        return a.x + b + c;
+;;      }
+;;    }
+;;  }
+;;}
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+
+; CHECK:      DW_TAG_subprogram
+; CHECK-NOT: DW_TAG
+; CHECK:        DW_AT_name {{.*}} "foo"
+; CHECK-NOT: NULL
+; CHECK:      DW_TAG_lexical_block
+
+; CHECK-NOT: {{DW_TAG|NULL}}
+; CHECK:        DW_TAG_structure_type
+; CHECK-NOT: {{DW_TAG|NULL}}
+; CHECK:          DW_AT_name {{.*}} "X"
+; CHECK:          NULL
+
+; CHECK-NOT: {{DW_TAG|NULL}}
+; CHECK:        DW_TAG_typedef
+; CHECK-NOT: {{DW_TAG|NULL}}
+; CHECK:          DW_AT_name {{.*}} "Y"
+
+; CHECK-NOT: {{DW_TAG|NULL}}
+; CHECK:        DW_TAG_lexical_block
+
+; CHECK-NOT: {{DW_TAG|NULL}}
+; CHECK:        DW_TAG_variable
+; CHECK-NOT: {{DW_TAG|NULL}}
+; CHECK:          DW_AT_name {{.*}} "c"
+
+; CHECK-NOT: {{DW_TAG|NULL}}
+; CHECK:        DW_TAG_variable
+; CHECK-NOT: {{DW_TAG|NULL}}
+; CHECK:          DW_AT_name {{.*}} "a"
+
+; CHECK-NOT: {{DW_TAG|NULL}}
+; CHECK:        DW_TAG_variable
+; CHECK-NOT: {{DW_TAG|NULL}}
+; CHECK:          DW_AT_name {{.*}} "b"
+
+; CHECK-NOT: {{DW_TAG}}
+; CHECK:        NULL
+
+
+%struct.X = type { i32 }
+
+@_ZZ3foovE1c = internal global i32 0, align 4
+
+; Function Attrs: nounwind
+define i32 @_Z3foov() #0 {
+entry:
+  %a = alloca %struct.X, align 4
+  %b = alloca i32, align 4
+  call void @llvm.dbg.declare(metadata %struct.X* %a, metadata !21, metadata !22), !dbg !23
+  call void @llvm.dbg.declare(metadata i32* %b, metadata !24, metadata !22), !dbg !25
+  %x = getelementptr inbounds %struct.X, %struct.X* %a, i32 0, i32 0, !dbg !26
+  %0 = load i32, i32* %x, align 4, !dbg !26
+  %1 = load i32, i32* %b, align 4, !dbg !26
+  %add = add nsw i32 %0, %1, !dbg !26
+  %2 = load i32, i32* @_ZZ3foovE1c, align 4, !dbg !26
+  %add1 = add nsw i32 %add, %2, !dbg !26
+  ret i32 %add1, !dbg !26
+}
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
+
+attributes #0 = { nounwind "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-realign-stack" "stack-protector-buffer-size"="8" "target-features"="+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { nounwind readnone }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!18, !19}
+!llvm.ident = !{!20}
+
+!0 = !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.7.0 (trunk 237245)", isOptimized: false, runtimeVersion: 0, emissionKind: 1, enums: !2, retainedTypes: !3, subprograms: !14, globals: !15, imports: !2)
+!1 = !DIFile(filename: "foo.cpp", directory: "/")
+!2 = !{}
+!3 = !{!4, !13}
+!4 = !DICompositeType(tag: DW_TAG_structure_type, name: "X", scope: !5, file: !1, line: 4, size: 32, align: 32, elements: !11)
+!5 = distinct !DILexicalBlock(scope: !6, file: !1, line: 3)
+!6 = distinct !DILexicalBlock(scope: !7, file: !1, line: 2)
+!7 = !DISubprogram(name: "foo", linkageName: "_Z3foov", scope: !1, file: !1, line: 1, type: !8, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: false, function: i32 ()* @_Z3foov, variables: !2)
+!8 = !DISubroutineType(types: !9)
+!9 = !{!10}
+!10 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
+!11 = !{!12}
+!12 = !DIDerivedType(tag: DW_TAG_member, name: "x", scope: !4, file: !1, line: 5, baseType: !10, size: 32, align: 32)
+!13 = !DIDerivedType(tag: DW_TAG_typedef, name: "Y", scope: !5, file: !1, line: 7, baseType: !10)
+!14 = !{!7}
+!15 = !{!16}
+!16 = !DIGlobalVariable(name: "c", scope: !17, file: !1, line: 11, type: !10, isLocal: true, isDefinition: true, variable: i32* @_ZZ3foovE1c)
+!17 = distinct !DILexicalBlock(scope: !5, file: !1, line: 8)
+!18 = !{i32 2, !"Dwarf Version", i32 4}
+!19 = !{i32 2, !"Debug Info Version", i32 3}
+!20 = !{!"clang version 3.7.0 (trunk 237245)"}
+!21 = !DILocalVariable(tag: DW_TAG_auto_variable, name: "a", scope: !17, file: !1, line: 9, type: !4)
+!22 = !DIExpression()
+!23 = !DILocation(line: 9, scope: !17)
+!24 = !DILocalVariable(tag: DW_TAG_auto_variable, name: "b", scope: !17, file: !1, line: 10, type: !13)
+!25 = !DILocation(line: 10, scope: !17)
+!26 = !DILocation(line: 12, scope: !17)