DebugInfo: pass alignment value only if it was forced

Preparation to implement DW_AT_alignment support:
 - We pass non-zero align value to DIBuilder only when alignment was forced
 - Modify tests to match this change

Differential Revision: https://reviews.llvm.org/D24426

llvm-svn: 284679

2 files changed, 85 insertions, 51 deletions

diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 1d80a1bf9da..9b623d7443c 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -44,6 +44,19 @@
 using namespace clang;
 using namespace clang::CodeGen;
 
+static uint32_t getTypeAlignIfRequired(const Type *Ty, const ASTContext &Ctx) {
+  auto TI = Ctx.getTypeInfo(Ty);
+  return TI.AlignIsRequired ? TI.Align : 0;
+}
+
+static uint32_t getTypeAlignIfRequired(QualType Ty, const ASTContext &Ctx) {
+  return getTypeAlignIfRequired(Ty.getTypePtr(), Ctx);
+}
+
+static uint32_t getDeclAlignIfRequired(const Decl *D, const ASTContext &Ctx) {
+  return D->hasAttr<AlignedAttr>() ? D->getMaxAlignment() : 0;
+}
+
 CGDebugInfo::CGDebugInfo(CodeGenModule &CGM)
     : CGM(CGM), DebugKind(CGM.getCodeGenOpts().getDebugInfo()),
       DebugTypeExtRefs(CGM.getCodeGenOpts().DebugTypeExtRefs),
@@ -594,21 +607,19 @@ llvm::DIType *CGDebugInfo::CreateType(const BuiltinType *BT) {
     BTName = BT->getName(CGM.getLangOpts());
     break;
   }
-  // Bit size, align and offset of the type.
+  // Bit size and offset of the type.
   uint64_t Size = CGM.getContext().getTypeSize(BT);
-  uint32_t Align = CGM.getContext().getTypeAlign(BT);
-  return DBuilder.createBasicType(BTName, Size, Align, Encoding);
+  return DBuilder.createBasicType(BTName, Size, Encoding);
 }
 
 llvm::DIType *CGDebugInfo::CreateType(const ComplexType *Ty) {
-  // Bit size, align and offset of the type.
+  // Bit size and offset of the type.
   llvm::dwarf::TypeKind Encoding = llvm::dwarf::DW_ATE_complex_float;
   if (Ty->isComplexIntegerType())
     Encoding = llvm::dwarf::DW_ATE_lo_user;
 
   uint64_t Size = CGM.getContext().getTypeSize(Ty);
-  uint32_t Align = CGM.getContext().getTypeAlign(Ty);
-  return DBuilder.createBasicType("complex", Size, Align, Encoding);
+  return DBuilder.createBasicType("complex", Size, Encoding);
 }
 
 llvm::DIType *CGDebugInfo::CreateQualifiedType(QualType Ty,
@@ -726,7 +737,7 @@ CGDebugInfo::getOrCreateRecordFwdDecl(const RecordType *Ty,
   const RecordDecl *D = RD->getDefinition();
   if (D && D->isCompleteDefinition()) {
     Size = CGM.getContext().getTypeSize(Ty);
-    Align = CGM.getContext().getTypeAlign(Ty);
+    Align = getDeclAlignIfRequired(D, CGM.getContext());
   }
 
   // Create the type.
@@ -749,7 +760,7 @@ llvm::DIType *CGDebugInfo::CreatePointerLikeType(llvm::dwarf::Tag Tag,
   // because that does not return the correct value for references.
   unsigned AS = CGM.getContext().getTargetAddressSpace(PointeeTy);
   uint64_t Size = CGM.getTarget().getPointerWidth(AS);
-  uint32_t Align = CGM.getContext().getTypeAlign(Ty);
+  auto Align = getTypeAlignIfRequired(Ty, CGM.getContext());
 
   if (Tag == llvm::dwarf::DW_TAG_reference_type ||
       Tag == llvm::dwarf::DW_TAG_rvalue_reference_type)
@@ -965,21 +976,20 @@ llvm::DIType *CGDebugInfo::createBitFieldType(const FieldDecl *BitFieldDecl,
       CGM.getTypes().getCGRecordLayout(RD).getBitFieldInfo(BitFieldDecl);
   uint64_t SizeInBits = BitFieldInfo.Size;
   assert(SizeInBits > 0 && "found named 0-width bitfield");
-  uint32_t AlignInBits = CGM.getContext().getTypeAlign(Ty);
   uint64_t StorageOffsetInBits =
       CGM.getContext().toBits(BitFieldInfo.StorageOffset);
   uint64_t OffsetInBits = StorageOffsetInBits + BitFieldInfo.Offset;
   llvm::DINode::DIFlags Flags = getAccessFlag(BitFieldDecl->getAccess(), RD);
   return DBuilder.createBitFieldMemberType(
-      RecordTy, Name, File, Line, SizeInBits, AlignInBits, OffsetInBits,
-      StorageOffsetInBits, Flags, DebugType);
+      RecordTy, Name, File, Line, SizeInBits, OffsetInBits, StorageOffsetInBits,
+      Flags, DebugType);
 }
 
 llvm::DIType *
 CGDebugInfo::createFieldType(StringRef name, QualType type, SourceLocation loc,
                              AccessSpecifier AS, uint64_t offsetInBits,
-                             llvm::DIFile *tunit, llvm::DIScope *scope,
-                             const RecordDecl *RD) {
+                             uint32_t AlignInBits, llvm::DIFile *tunit,
+                             llvm::DIScope *scope, const RecordDecl *RD) {
   llvm::DIType *debugType = getOrCreateType(type, tunit);
 
   // Get the location for the field.
@@ -987,16 +997,17 @@ CGDebugInfo::createFieldType(StringRef name, QualType type, SourceLocation loc,
   unsigned line = getLineNumber(loc);
 
   uint64_t SizeInBits = 0;
-  uint32_t AlignInBits = 0;
+  auto Align = AlignInBits;
   if (!type->isIncompleteArrayType()) {
     TypeInfo TI = CGM.getContext().getTypeInfo(type);
     SizeInBits = TI.Width;
-    AlignInBits = TI.Align;
+    if (!Align)
+      Align = getTypeAlignIfRequired(type, CGM.getContext());
   }
 
   llvm::DINode::DIFlags flags = getAccessFlag(AS, RD);
   return DBuilder.createMemberType(scope, name, file, line, SizeInBits,
-                                   AlignInBits, offsetInBits, flags, debugType);
+                                   Align, offsetInBits, flags, debugType);
 }
 
 void CGDebugInfo::CollectRecordLambdaFields(
@@ -1018,9 +1029,10 @@ void CGDebugInfo::CollectRecordLambdaFields(
       VarDecl *V = C.getCapturedVar();
       StringRef VName = V->getName();
       llvm::DIFile *VUnit = getOrCreateFile(Loc);
+      auto Align = getDeclAlignIfRequired(V, CGM.getContext());
       llvm::DIType *FieldType = createFieldType(
           VName, Field->getType(), Loc, Field->getAccess(),
-          layout.getFieldOffset(fieldno), VUnit, RecordTy, CXXDecl);
+          layout.getFieldOffset(fieldno), Align, VUnit, RecordTy, CXXDecl);
       elements.push_back(FieldType);
     } else if (C.capturesThis()) {
       // TODO: Need to handle 'this' in some way by probably renaming the
@@ -1062,8 +1074,9 @@ CGDebugInfo::CreateRecordStaticField(const VarDecl *Var, llvm::DIType *RecordTy,
   }
 
   llvm::DINode::DIFlags Flags = getAccessFlag(Var->getAccess(), RD);
+  auto Align = getDeclAlignIfRequired(Var, CGM.getContext());
   llvm::DIDerivedType *GV = DBuilder.createStaticMemberType(
-      RecordTy, VName, VUnit, LineNumber, VTy, Flags, C);
+      RecordTy, VName, VUnit, LineNumber, VTy, Flags, C, Align);
   StaticDataMemberCache[Var->getCanonicalDecl()].reset(GV);
   return GV;
 }
@@ -1083,9 +1096,10 @@ void CGDebugInfo::CollectRecordNormalField(
   if (field->isBitField()) {
     FieldType = createBitFieldType(field, RecordTy, RD);
   } else {
+    auto Align = getDeclAlignIfRequired(field, CGM.getContext());
     FieldType =
         createFieldType(name, type, field->getLocation(), field->getAccess(),
-                        OffsetInBits, tunit, RecordTy, RD);
+                        OffsetInBits, Align, tunit, RecordTy, RD);
   }
 
   elements.push_back(FieldType);
@@ -1181,7 +1195,7 @@ llvm::DISubroutineType *CGDebugInfo::getOrCreateInstanceMethodType(
     QualType PointeeTy = ThisPtrTy->getPointeeType();
     unsigned AS = CGM.getContext().getTargetAddressSpace(PointeeTy);
     uint64_t Size = CGM.getTarget().getPointerWidth(AS);
-    uint32_t Align = CGM.getContext().getTypeAlign(ThisPtrTy);
+    auto Align = getTypeAlignIfRequired(ThisPtrTy, CGM.getContext());
     llvm::DIType *PointeeType = getOrCreateType(PointeeTy, Unit);
     llvm::DIType *ThisPtrType =
         DBuilder.createPointerType(PointeeType, Size, Align);
@@ -1968,7 +1982,7 @@ llvm::DIType *CGDebugInfo::CreateTypeDefinition(const ObjCInterfaceType *Ty,
 
   // Bit size, align and offset of the type.
   uint64_t Size = CGM.getContext().getTypeSize(Ty);
-  uint32_t Align = CGM.getContext().getTypeAlign(Ty);
+  auto Align = getTypeAlignIfRequired(Ty, CGM.getContext());
 
   llvm::DINode::DIFlags Flags = llvm::DINode::FlagZero;
   if (ID->getImplementation())
@@ -2060,7 +2074,7 @@ llvm::DIType *CGDebugInfo::CreateTypeDefinition(const ObjCInterfaceType *Ty,
       FieldSize = Field->isBitField()
                       ? Field->getBitWidthValue(CGM.getContext())
                       : CGM.getContext().getTypeSize(FType);
-      FieldAlign = CGM.getContext().getTypeAlign(FType);
+      FieldAlign = getTypeAlignIfRequired(FType, CGM.getContext());
     }
 
     uint64_t FieldOffset;
@@ -2134,7 +2148,7 @@ llvm::DIType *CGDebugInfo::CreateType(const VectorType *Ty,
   llvm::DINodeArray SubscriptArray = DBuilder.getOrCreateArray(Subscript);
 
   uint64_t Size = CGM.getContext().getTypeSize(Ty);
-  uint32_t Align = CGM.getContext().getTypeAlign(Ty);
+  auto Align = getTypeAlignIfRequired(Ty, CGM.getContext());
 
   return DBuilder.createVectorType(Size, Align, ElementTy, SubscriptArray);
 }
@@ -2146,21 +2160,21 @@ llvm::DIType *CGDebugInfo::CreateType(const ArrayType *Ty, llvm::DIFile *Unit) {
   // FIXME: make getTypeAlign() aware of VLAs and incomplete array types
   if (const auto *VAT = dyn_cast<VariableArrayType>(Ty)) {
     Size = 0;
-    Align =
-        CGM.getContext().getTypeAlign(CGM.getContext().getBaseElementType(VAT));
+    Align = getTypeAlignIfRequired(CGM.getContext().getBaseElementType(VAT),
+                                   CGM.getContext());
   } else if (Ty->isIncompleteArrayType()) {
     Size = 0;
     if (Ty->getElementType()->isIncompleteType())
       Align = 0;
     else
-      Align = CGM.getContext().getTypeAlign(Ty->getElementType());
+      Align = getTypeAlignIfRequired(Ty->getElementType(), CGM.getContext());
   } else if (Ty->isIncompleteType()) {
     Size = 0;
     Align = 0;
   } else {
     // Size and align of the whole array, not the element type.
     Size = CGM.getContext().getTypeSize(Ty);
-    Align = CGM.getContext().getTypeAlign(Ty);
+    Align = getTypeAlignIfRequired(Ty, CGM.getContext());
   }
 
   // Add the dimensions of the array.  FIXME: This loses CV qualifiers from
@@ -2269,7 +2283,7 @@ llvm::DIType *CGDebugInfo::CreateEnumType(const EnumType *Ty) {
   uint32_t Align = 0;
   if (!ED->getTypeForDecl()->isIncompleteType()) {
     Size = CGM.getContext().getTypeSize(ED->getTypeForDecl());
-    Align = CGM.getContext().getTypeAlign(ED->getTypeForDecl());
+    Align = getDeclAlignIfRequired(ED, CGM.getContext());
   }
 
   SmallString<256> FullName = getUniqueTagTypeName(Ty, CGM, TheCU);
@@ -2312,7 +2326,7 @@ llvm::DIType *CGDebugInfo::CreateTypeDefinition(const EnumType *Ty) {
   uint32_t Align = 0;
   if (!ED->getTypeForDecl()->isIncompleteType()) {
     Size = CGM.getContext().getTypeSize(ED->getTypeForDecl());
-    Align = CGM.getContext().getTypeAlign(ED->getTypeForDecl());
+    Align = getDeclAlignIfRequired(ED, CGM.getContext());
   }
 
   SmallString<256> FullName = getUniqueTagTypeName(Ty, CGM, TheCU);
@@ -2609,7 +2623,7 @@ llvm::DICompositeType *CGDebugInfo::CreateLimitedType(const RecordType *Ty) {
     return getOrCreateRecordFwdDecl(Ty, RDContext);
 
   uint64_t Size = CGM.getContext().getTypeSize(Ty);
-  uint32_t Align = CGM.getContext().getTypeAlign(Ty);
+  auto Align = getDeclAlignIfRequired(D, CGM.getContext());
 
   SmallString<256> FullName = getUniqueTagTypeName(Ty, CGM, TheCU);
 
@@ -2678,7 +2692,7 @@ llvm::DIType *CGDebugInfo::CreateMemberType(llvm::DIFile *Unit, QualType FType,
                                             StringRef Name, uint64_t *Offset) {
   llvm::DIType *FieldTy = CGDebugInfo::getOrCreateType(FType, Unit);
   uint64_t FieldSize = CGM.getContext().getTypeSize(FType);
-  uint32_t FieldAlign = CGM.getContext().getTypeAlign(FType);
+  auto FieldAlign = getTypeAlignIfRequired(FType, CGM.getContext());
   llvm::DIType *Ty =
       DBuilder.createMemberType(Unit, Name, Unit, 0, FieldSize, FieldAlign,
                                 *Offset, llvm::DINode::FlagZero, FieldTy);
@@ -2812,9 +2826,10 @@ CGDebugInfo::getGlobalVariableForwardDeclaration(const VarDecl *VD) {
   unsigned Line = getLineNumber(Loc);
 
   collectVarDeclProps(VD, Unit, Line, T, Name, LinkageName, DContext);
+  auto Align = getDeclAlignIfRequired(VD, CGM.getContext());
   auto *GV = DBuilder.createTempGlobalVariableFwdDecl(
       DContext, Name, LinkageName, Unit, Line, getOrCreateType(T, Unit),
-      !VD->isExternallyVisible(), nullptr, nullptr);
+      !VD->isExternallyVisible(), nullptr, nullptr, Align);
   FwdDeclReplaceMap.emplace_back(
       std::piecewise_construct,
       std::make_tuple(cast<VarDecl>(VD->getCanonicalDecl())),
@@ -3243,6 +3258,9 @@ void CGDebugInfo::EmitDeclare(const VarDecl *VD, llvm::Value *Storage,
   llvm::DINode::DIFlags Flags = llvm::DINode::FlagZero;
   if (VD->isImplicit())
     Flags |= llvm::DINode::FlagArtificial;
+
+  auto Align = getDeclAlignIfRequired(VD, CGM.getContext());
+
   // If this is the first argument and it is implicit then
   // give it an object pointer flag.
   // FIXME: There has to be a better way to do this, but for static
@@ -3277,7 +3295,7 @@ void CGDebugInfo::EmitDeclare(const VarDecl *VD, llvm::Value *Storage,
                     ? DBuilder.createParameterVariable(Scope, VD->getName(),
                                                        *ArgNo, Unit, Line, Ty)
                     : DBuilder.createAutoVariable(Scope, VD->getName(), Unit,
-                                                  Line, Ty);
+                                                  Line, Ty, Align);
 
       // Insert an llvm.dbg.declare into the current block.
       DBuilder.insertDeclare(Storage, D, DBuilder.createExpression(Expr),
@@ -3307,9 +3325,10 @@ void CGDebugInfo::EmitDeclare(const VarDecl *VD, llvm::Value *Storage,
           continue;
 
         // Use VarDecl's Tag, Scope and Line number.
+        auto FieldAlign = getDeclAlignIfRequired(Field, CGM.getContext());
         auto *D = DBuilder.createAutoVariable(
             Scope, FieldName, Unit, Line, FieldTy, CGM.getLangOpts().Optimize,
-            Flags | llvm::DINode::FlagArtificial);
+            Flags | llvm::DINode::FlagArtificial, FieldAlign);
 
         // Insert an llvm.dbg.declare into the current block.
         DBuilder.insertDeclare(Storage, D, DBuilder.createExpression(Expr),
@@ -3320,13 +3339,13 @@ void CGDebugInfo::EmitDeclare(const VarDecl *VD, llvm::Value *Storage,
   }
 
   // Create the descriptor for the variable.
-  auto *D =
-      ArgNo
-          ? DBuilder.createParameterVariable(Scope, Name, *ArgNo, Unit, Line,
-                                             Ty, CGM.getLangOpts().Optimize,
-                                             Flags)
-          : DBuilder.createAutoVariable(Scope, Name, Unit, Line, Ty,
-                                        CGM.getLangOpts().Optimize, Flags);
+  auto *D = ArgNo
+                ? DBuilder.createParameterVariable(
+                      Scope, Name, *ArgNo, Unit, Line, Ty,
+                      CGM.getLangOpts().Optimize, Flags)
+                : DBuilder.createAutoVariable(Scope, Name, Unit, Line, Ty,
+                                              CGM.getLangOpts().Optimize, Flags,
+                                              Align);
 
   // Insert an llvm.dbg.declare into the current block.
   DBuilder.insertDeclare(Storage, D, DBuilder.createExpression(Expr),
@@ -3405,9 +3424,10 @@ void CGDebugInfo::EmitDeclareOfBlockDeclRefVariable(
   }
 
   // Create the descriptor for the variable.
+  auto Align = getDeclAlignIfRequired(VD, CGM.getContext());
   auto *D = DBuilder.createAutoVariable(
       cast<llvm::DILocalScope>(LexicalBlockStack.back()), VD->getName(), Unit,
-      Line, Ty);
+      Line, Ty, false, llvm::DINode::FlagZero, Align);
 
   // Insert an llvm.dbg.declare into the current block.
   auto DL = llvm::DebugLoc::get(Line, Column, LexicalBlockStack.back());
@@ -3536,17 +3556,19 @@ void CGDebugInfo::EmitDeclareOfBlockLiteralArgVariable(const CGBlockInfo &block,
     llvm::DIType *fieldType;
     if (capture->isByRef()) {
       TypeInfo PtrInfo = C.getTypeInfo(C.VoidPtrTy);
+      auto Align = PtrInfo.AlignIsRequired ? PtrInfo.Align : 0;
 
       // FIXME: this creates a second copy of this type!
       uint64_t xoffset;
       fieldType = EmitTypeForVarWithBlocksAttr(variable, &xoffset);
       fieldType = DBuilder.createPointerType(fieldType, PtrInfo.Width);
-      fieldType = DBuilder.createMemberType(
-          tunit, name, tunit, line, PtrInfo.Width, PtrInfo.Align, offsetInBits,
-          llvm::DINode::FlagZero, fieldType);
+      fieldType = DBuilder.createMemberType(tunit, name, tunit, line,
+                                            PtrInfo.Width, Align, offsetInBits,
+                                            llvm::DINode::FlagZero, fieldType);
     } else {
+      auto Align = getDeclAlignIfRequired(variable, CGM.getContext());
       fieldType = createFieldType(name, variable->getType(), loc, AS_public,
-                                  offsetInBits, tunit, tunit);
+                                  offsetInBits, Align, tunit, tunit);
     }
     fields.push_back(fieldType);
   }
@@ -3559,8 +3581,7 @@ void CGDebugInfo::EmitDeclareOfBlockLiteralArgVariable(const CGBlockInfo &block,
 
   llvm::DIType *type =
       DBuilder.createStructType(tunit, typeName.str(), tunit, line,
-                                CGM.getContext().toBits(block.BlockSize),
-                                CGM.getContext().toBits(block.BlockAlign),
+                                CGM.getContext().toBits(block.BlockSize), 0,
                                 llvm::DINode::FlagZero, nullptr, fieldsArray);
   type = DBuilder.createPointerType(type, CGM.PointerWidthInBits);
 
@@ -3654,10 +3675,11 @@ void CGDebugInfo::EmitGlobalVariable(llvm::GlobalVariable *Var,
            "unnamed non-anonymous struct or union?");
     GV = CollectAnonRecordDecls(RD, Unit, LineNo, LinkageName, Var, DContext);
   } else {
+    auto Align = getDeclAlignIfRequired(D, CGM.getContext());
     GV = DBuilder.createGlobalVariable(
         DContext, DeclName, LinkageName, Unit, LineNo, getOrCreateType(T, Unit),
         Var->hasLocalLinkage(), /*Expr=*/nullptr,
-        getOrCreateStaticDataMemberDeclarationOrNull(D));
+        getOrCreateStaticDataMemberDeclarationOrNull(D), Align);
     Var->addDebugInfo(GV);
   }
   DeclCache[D->getCanonicalDecl()].reset(GV);
@@ -3667,6 +3689,7 @@ void CGDebugInfo::EmitGlobalVariable(const ValueDecl *VD, const APValue &Init) {
   assert(DebugKind >= codegenoptions::LimitedDebugInfo);
   if (VD->hasAttr<NoDebugAttr>())
     return;
+  auto Align = getDeclAlignIfRequired(VD, CGM.getContext());
   // Create the descriptor for the variable.
   llvm::DIFile *Unit = getOrCreateFile(VD->getLocation());
   StringRef Name = VD->getName();
@@ -3709,7 +3732,8 @@ void CGDebugInfo::EmitGlobalVariable(const ValueDecl *VD, const APValue &Init) {
         DBuilder.createConstantValueExpression(Init.getInt().getExtValue());
   GV.reset(DBuilder.createGlobalVariable(
       DContext, Name, StringRef(), Unit, getLineNumber(VD->getLocation()), Ty,
-      true, InitExpr, getOrCreateStaticDataMemberDeclarationOrNull(VarD)));
+      true, InitExpr, getOrCreateStaticDataMemberDeclarationOrNull(VarD),
+      Align));
 }
 
 llvm::DIScope *CGDebugInfo::getCurrentContextDescriptor(const Decl *D) {
diff --git a/clang/lib/CodeGen/CGDebugInfo.h b/clang/lib/CodeGen/CGDebugInfo.h
index 17a94633142..d2af9be9b6c 100644
--- a/clang/lib/CodeGen/CGDebugInfo.h
+++ b/clang/lib/CodeGen/CGDebugInfo.h
@@ -235,9 +235,19 @@ class CGDebugInfo {
 
   llvm::DIType *createFieldType(StringRef name, QualType type,
                                 SourceLocation loc, AccessSpecifier AS,
+                                uint64_t offsetInBits,
+                                uint32_t AlignInBits,
+                                llvm::DIFile *tunit, llvm::DIScope *scope,
+                                const RecordDecl *RD = nullptr);
+
+  llvm::DIType *createFieldType(StringRef name, QualType type,
+                                SourceLocation loc, AccessSpecifier AS,
                                 uint64_t offsetInBits, llvm::DIFile *tunit,
                                 llvm::DIScope *scope,
-                                const RecordDecl *RD = nullptr);
+                                const RecordDecl *RD = nullptr) {
+    return createFieldType(name, type, loc, AS, offsetInBits, 0, tunit, scope,
+                           RD);
+  }
 
   /// Create new bit field member.
   llvm::DIType *createBitFieldType(const FieldDecl *BitFieldDecl,