lib/CodeGen/CGDebugInfo.h

//===--- CGDebugInfo.h - DebugInfo for LLVM CodeGen -------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This is the source-level debug info generator for llvm translation.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_LIB_CODEGEN_CGDEBUGINFO_H
#define LLVM_CLANG_LIB_CODEGEN_CGDEBUGINFO_H

#include "CGBuilder.h"
#include "clang/AST/Expr.h"
#include "clang/AST/Type.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Frontend/CodeGenOptions.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/IR/DIBuilder.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/Support/Allocator.h"

namespace llvm {
  class MDNode;
}

namespace clang {
  class CXXMethodDecl;
  class VarDecl;
  class ObjCInterfaceDecl;
  class ObjCIvarDecl;
  class ClassTemplateSpecializationDecl;
  class GlobalDecl;
  class UsingDecl;

namespace CodeGen {
  class CodeGenModule;
  class CodeGenFunction;
  class CGBlockInfo;

/// \brief This class gathers all debug information during compilation
/// and is responsible for emitting to llvm globals or pass directly to
/// the backend.
class CGDebugInfo {
  friend class ApplyDebugLocation;
  friend class SaveAndRestoreLocation;
  CodeGenModule &CGM;
  const CodeGenOptions::DebugInfoKind DebugKind;
  llvm::DIBuilder DBuilder;
  llvm::DICompileUnit TheCU;
  SourceLocation CurLoc;
  llvm::DIType VTablePtrType;
  llvm::DIType ClassTy;
  llvm::MDCompositeType *ObjTy = nullptr;
  llvm::DIType SelTy;
  llvm::DIType OCLImage1dDITy, OCLImage1dArrayDITy, OCLImage1dBufferDITy;
  llvm::DIType OCLImage2dDITy, OCLImage2dArrayDITy;
  llvm::DIType OCLImage3dDITy;
  llvm::DIType OCLEventDITy;
  llvm::DIType BlockLiteralGeneric;

  /// \brief Cache of previously constructed Types.
  llvm::DenseMap<const void *, llvm::TrackingMDRef> TypeCache;

  struct ObjCInterfaceCacheEntry {
    const ObjCInterfaceType *Type;
    llvm::DIType Decl;
    llvm::DIFile Unit;
    ObjCInterfaceCacheEntry(const ObjCInterfaceType *Type, llvm::DIType Decl,
                            llvm::DIFile Unit)
        : Type(Type), Decl(Decl), Unit(Unit) {}
  };

  /// \brief Cache of previously constructed interfaces
  /// which may change.
  llvm::SmallVector<ObjCInterfaceCacheEntry, 32> ObjCInterfaceCache;

  /// \brief list of interfaces we want to keep even if orphaned.
  std::vector<void *> RetainedTypes;

  /// \brief Cache of forward declared types to RAUW at the end of
  /// compilation.
  std::vector<std::pair<const TagType *, llvm::TrackingMDRef>> ReplaceMap;

  /// \brief Cache of replaceable forward declarartions (functions and
  /// variables) to RAUW at the end of compilation.
  std::vector<std::pair<const DeclaratorDecl *, llvm::TrackingMDRef>>
      FwdDeclReplaceMap;

  // LexicalBlockStack - Keep track of our current nested lexical block.
  std::vector<llvm::TrackingMDNodeRef> LexicalBlockStack;
  llvm::DenseMap<const Decl *, llvm::TrackingMDRef> RegionMap;
  // FnBeginRegionCount - Keep track of LexicalBlockStack counter at the
  // beginning of a function. This is used to pop unbalanced regions at
  // the end of a function.
  std::vector<unsigned> FnBeginRegionCount;

  /// \brief This is a storage for names that are
  /// constructed on demand. For example, C++ destructors, C++ operators etc..
  llvm::BumpPtrAllocator DebugInfoNames;
  StringRef CWDName;

  llvm::DenseMap<const char *, llvm::TrackingMDRef> DIFileCache;
  llvm::DenseMap<const FunctionDecl *, llvm::TrackingMDRef> SPCache;
  /// \brief Cache declarations relevant to DW_TAG_imported_declarations (C++
  /// using declarations) that aren't covered by other more specific caches.
  llvm::DenseMap<const Decl *, llvm::TrackingMDRef> DeclCache;
  llvm::DenseMap<const NamespaceDecl *, llvm::TrackingMDRef> NameSpaceCache;
  llvm::DenseMap<const NamespaceAliasDecl *, llvm::TrackingMDRef>
      NamespaceAliasCache;
  llvm::DenseMap<const Decl *, llvm::TrackingMDRef> StaticDataMemberCache;

  /// Helper functions for getOrCreateType.
  unsigned Checksum(const ObjCInterfaceDecl *InterfaceDecl);
  llvm::DIType CreateType(const BuiltinType *Ty);
  llvm::DIType CreateType(const ComplexType *Ty);
  llvm::DIType CreateQualifiedType(QualType Ty, llvm::DIFile Fg);
  llvm::DIType CreateType(const TypedefType *Ty, llvm::DIFile Fg);
  llvm::DIType CreateType(const TemplateSpecializationType *Ty, llvm::DIFile Fg);
  llvm::DIType CreateType(const ObjCObjectPointerType *Ty,
                          llvm::DIFile F);
  llvm::DIType CreateType(const PointerType *Ty, llvm::DIFile F);
  llvm::DIType CreateType(const BlockPointerType *Ty, llvm::DIFile F);
  llvm::DIType CreateType(const FunctionType *Ty, llvm::DIFile F);
  llvm::DIType CreateType(const RecordType *Tyg);
  llvm::DIType CreateTypeDefinition(const RecordType *Ty);
  llvm::MDCompositeType *CreateLimitedType(const RecordType *Ty);
  void CollectContainingType(const CXXRecordDecl *RD,
                             llvm::MDCompositeType *CT);
  llvm::DIType CreateType(const ObjCInterfaceType *Ty, llvm::DIFile F);
  llvm::DIType CreateTypeDefinition(const ObjCInterfaceType *Ty, llvm::DIFile F);
  llvm::DIType CreateType(const ObjCObjectType *Ty, llvm::DIFile F);
  llvm::DIType CreateType(const VectorType *Ty, llvm::DIFile F);
  llvm::DIType CreateType(const ArrayType *Ty, llvm::DIFile F);
  llvm::DIType CreateType(const LValueReferenceType *Ty, llvm::DIFile F);
  llvm::DIType CreateType(const RValueReferenceType *Ty, llvm::DIFile Unit);
  llvm::DIType CreateType(const MemberPointerType *Ty, llvm::DIFile F);
  llvm::DIType CreateType(const AtomicType *Ty, llvm::DIFile F);
  llvm::DIType CreateEnumType(const EnumType *Ty);
  llvm::DIType CreateTypeDefinition(const EnumType *Ty);
  llvm::DIType CreateSelfType(const QualType &QualTy, llvm::DIType Ty);
  llvm::DIType getTypeOrNull(const QualType);
  llvm::MDSubroutineType *getOrCreateMethodType(const CXXMethodDecl *Method,
                                                llvm::DIFile F);
  llvm::MDSubroutineType *
  getOrCreateInstanceMethodType(QualType ThisPtr, const FunctionProtoType *Func,
                                llvm::DIFile Unit);
  llvm::MDSubroutineType *
  getOrCreateFunctionType(const Decl *D, QualType FnType, llvm::DIFile F);
  llvm::DIType getOrCreateVTablePtrType(llvm::DIFile F);
  llvm::DINameSpace getOrCreateNameSpace(const NamespaceDecl *N);
  llvm::DIType getOrCreateTypeDeclaration(QualType PointeeTy, llvm::DIFile F);
  llvm::DIType CreatePointerLikeType(llvm::dwarf::Tag Tag,
                                     const Type *Ty, QualType PointeeTy,
                                     llvm::DIFile F);

  llvm::Value *getCachedInterfaceTypeOrNull(const QualType Ty);
  llvm::DIType getOrCreateStructPtrType(StringRef Name, llvm::DIType &Cache);

  llvm::DISubprogram CreateCXXMemberFunction(const CXXMethodDecl *Method,
                                             llvm::DIFile F,
                                             llvm::DIType RecordTy);

  void CollectCXXMemberFunctions(const CXXRecordDecl *Decl, llvm::DIFile F,
                                 SmallVectorImpl<llvm::Metadata *> &E,
                                 llvm::DIType T);

  void CollectCXXBases(const CXXRecordDecl *Decl, llvm::DIFile F,
                       SmallVectorImpl<llvm::Metadata *> &EltTys,
                       llvm::DIType RecordTy);

  llvm::DIArray
  CollectTemplateParams(const TemplateParameterList *TPList,
                        ArrayRef<TemplateArgument> TAList,
                        llvm::DIFile Unit);
  llvm::DIArray
  CollectFunctionTemplateParams(const FunctionDecl *FD, llvm::DIFile Unit);
  llvm::DIArray
  CollectCXXTemplateParams(const ClassTemplateSpecializationDecl *TS,
                           llvm::DIFile F);

  llvm::DIType createFieldType(StringRef name, QualType type,
                               uint64_t sizeInBitsOverride, SourceLocation loc,
                               AccessSpecifier AS,
                               uint64_t offsetInBits,
                               llvm::DIFile tunit,
                               llvm::DIScope scope,
                               const RecordDecl* RD = nullptr);

  // Helpers for collecting fields of a record.
  void CollectRecordLambdaFields(const CXXRecordDecl *CXXDecl,
                                 SmallVectorImpl<llvm::Metadata *> &E,
                                 llvm::DIType RecordTy);
  llvm::DIDerivedType CreateRecordStaticField(const VarDecl *Var,
                                              llvm::DIType RecordTy,
                                              const RecordDecl* RD);
  void CollectRecordNormalField(const FieldDecl *Field, uint64_t OffsetInBits,
                                llvm::DIFile F,
                                SmallVectorImpl<llvm::Metadata *> &E,
                                llvm::DIType RecordTy, const RecordDecl *RD);
  void CollectRecordFields(const RecordDecl *Decl, llvm::DIFile F,
                           SmallVectorImpl<llvm::Metadata *> &E,
                           llvm::DICompositeType RecordTy);

  void CollectVTableInfo(const CXXRecordDecl *Decl, llvm::DIFile F,
                         SmallVectorImpl<llvm::Metadata *> &EltTys);

  // CreateLexicalBlock - Create a new lexical block node and push it on
  // the stack.
  void CreateLexicalBlock(SourceLocation Loc);

public:
  CGDebugInfo(CodeGenModule &CGM);
  ~CGDebugInfo();

  void finalize();

  /// \brief Update the current source location. If \arg loc is
  /// invalid it is ignored.
  void setLocation(SourceLocation Loc);

  /// \brief Emit metadata to indicate a change in line/column
  /// information in the source file.
  void EmitLocation(CGBuilderTy &Builder, SourceLocation Loc);

  /// \brief Emit a call to llvm.dbg.function.start to indicate
  /// start of a new function.
  /// \param Loc       The location of the function header.
  /// \param ScopeLoc  The location of the function body.
  void EmitFunctionStart(GlobalDecl GD,
                         SourceLocation Loc, SourceLocation ScopeLoc,
                         QualType FnType, llvm::Function *Fn,
                         CGBuilderTy &Builder);

  /// \brief Constructs the debug code for exiting a function.
  void EmitFunctionEnd(CGBuilderTy &Builder);

  /// \brief Emit metadata to indicate the beginning of a
  /// new lexical block and push the block onto the stack.
  void EmitLexicalBlockStart(CGBuilderTy &Builder, SourceLocation Loc);

  /// \brief Emit metadata to indicate the end of a new lexical
  /// block and pop the current block.
  void EmitLexicalBlockEnd(CGBuilderTy &Builder, SourceLocation Loc);

  /// \brief Emit call to llvm.dbg.declare for an automatic
  /// variable declaration.
  void EmitDeclareOfAutoVariable(const VarDecl *Decl, llvm::Value *AI,
                                 CGBuilderTy &Builder);

  /// \brief Emit call to llvm.dbg.declare for an
  /// imported variable declaration in a block.
  void EmitDeclareOfBlockDeclRefVariable(const VarDecl *variable,
                                         llvm::Value *storage,
                                         CGBuilderTy &Builder,
                                         const CGBlockInfo &blockInfo,
                                         llvm::Instruction *InsertPoint = 0);

  /// \brief Emit call to llvm.dbg.declare for an argument
  /// variable declaration.
  void EmitDeclareOfArgVariable(const VarDecl *Decl, llvm::Value *AI,
                                unsigned ArgNo, CGBuilderTy &Builder);

  /// \brief Emit call to
  /// llvm.dbg.declare for the block-literal argument to a block
  /// invocation function.
  void EmitDeclareOfBlockLiteralArgVariable(const CGBlockInfo &block,
                                            llvm::Value *Arg, unsigned ArgNo,
                                            llvm::Value *LocalAddr,
                                            CGBuilderTy &Builder);

  /// \brief Emit information about a global variable.
  void EmitGlobalVariable(llvm::GlobalVariable *GV, const VarDecl *Decl);

  /// \brief Emit global variable's debug info.
  void EmitGlobalVariable(const ValueDecl *VD, llvm::Constant *Init);

  /// \brief Emit C++ using directive.
  void EmitUsingDirective(const UsingDirectiveDecl &UD);

  /// \brief Emit the type explicitly casted to.
  void EmitExplicitCastType(QualType Ty);

  /// \brief Emit C++ using declaration.
  void EmitUsingDecl(const UsingDecl &UD);

  /// \brief Emit C++ namespace alias.
  llvm::DIImportedEntity EmitNamespaceAlias(const NamespaceAliasDecl &NA);

  /// \brief Emit record type's standalone debug info.
  llvm::DIType getOrCreateRecordType(QualType Ty, SourceLocation L);

  /// \brief Emit an objective c interface type standalone
  /// debug info.
  llvm::DIType getOrCreateInterfaceType(QualType Ty,
                                        SourceLocation Loc);

  void completeType(const EnumDecl *ED);
  void completeType(const RecordDecl *RD);
  void completeRequiredType(const RecordDecl *RD);
  void completeClassData(const RecordDecl *RD);

  void completeTemplateDefinition(const ClassTemplateSpecializationDecl &SD);

private:
  /// \brief Emit call to llvm.dbg.declare for a variable declaration.
  /// Tag accepts custom types DW_TAG_arg_variable and DW_TAG_auto_variable,
  /// otherwise would be of type llvm::dwarf::Tag.
  void EmitDeclare(const VarDecl *decl, llvm::dwarf::Tag Tag, llvm::Value *AI,
                   unsigned ArgNo, CGBuilderTy &Builder);

  // EmitTypeForVarWithBlocksAttr - Build up structure info for the byref.
  // See BuildByRefType.
  llvm::DIType EmitTypeForVarWithBlocksAttr(const VarDecl *VD,
                                            uint64_t *OffSet);

  /// \brief Get context info for the decl.
  llvm::DIScope getContextDescriptor(const Decl *Decl);

  llvm::DIScope getCurrentContextDescriptor(const Decl *Decl);

  /// \brief Create a forward decl for a RecordType in a given context.
  llvm::MDCompositeType *getOrCreateRecordFwdDecl(const RecordType *,
                                                  llvm::MDScope *);

  /// \brief Create a set of decls for the context chain.
  llvm::DIDescriptor createContextChain(const Decl *Decl);

  /// \brief Return current directory name.
  StringRef getCurrentDirname();

  /// \brief Create new compile unit.
  void CreateCompileUnit();

  /// \brief Get the file debug info descriptor for the input
  /// location.
  llvm::DIFile getOrCreateFile(SourceLocation Loc);

  /// \brief Get the file info for main compile unit.
  llvm::DIFile getOrCreateMainFile();

  /// \brief Get the type from the cache or create a new type if
  /// necessary.
  llvm::DIType getOrCreateType(QualType Ty, llvm::DIFile Fg);

  /// \brief Get the type from the cache or create a new
  /// partial type if necessary.
  llvm::DIType getOrCreateLimitedType(const RecordType *Ty, llvm::DIFile F);

  /// \brief Create type metadata for a source language type.
  llvm::DIType CreateTypeNode(QualType Ty, llvm::DIFile Fg);

  /// \brief return the underlying ObjCInterfaceDecl
  /// if Ty is an ObjCInterface or a pointer to one.
  ObjCInterfaceDecl* getObjCInterfaceDecl(QualType Ty);

  /// \brief Create new member and increase Offset by FType's size.
  llvm::DIType CreateMemberType(llvm::DIFile Unit, QualType FType,
                                StringRef Name, uint64_t *Offset);

  /// \brief Retrieve the DIDescriptor, if any, for the canonical form of this
  /// declaration.
  llvm::DebugNode *getDeclarationOrDefinition(const Decl *D);

  /// \brief Return debug info descriptor to describe method
  /// declaration for the given method definition.
  llvm::DISubprogram getFunctionDeclaration(const Decl *D);

  /// Return debug info descriptor to describe in-class static data member
  /// declaration for the given out-of-class definition.
  llvm::DIDerivedType
  getOrCreateStaticDataMemberDeclarationOrNull(const VarDecl *D);

  /// \brief Create a DISubprogram describing the forward
  /// decalration represented in the given FunctionDecl.
  llvm::DISubprogram getFunctionForwardDeclaration(const FunctionDecl *FD);

  /// \brief Create a DIGlobalVariable describing the forward
  /// decalration represented in the given VarDecl.
  llvm::DIGlobalVariable getGlobalVariableForwardDeclaration(const VarDecl *VD);

  /// Return a global variable that represents one of the collection of
  /// global variables created for an anonmyous union.
  llvm::DIGlobalVariable
  CollectAnonRecordDecls(const RecordDecl *RD, llvm::DIFile Unit,
                         unsigned LineNo, StringRef LinkageName,
                         llvm::GlobalVariable *Var, llvm::MDScope *DContext);

  /// \brief Get function name for the given FunctionDecl. If the
  /// name is constructed on demand (e.g. C++ destructor) then the name
  /// is stored on the side.
  StringRef getFunctionName(const FunctionDecl *FD);

  /// \brief Returns the unmangled name of an Objective-C method.
  /// This is the display name for the debugging info.
  StringRef getObjCMethodName(const ObjCMethodDecl *FD);

  /// \brief Return selector name. This is used for debugging
  /// info.
  StringRef getSelectorName(Selector S);

  /// \brief Get class name including template argument list.
  StringRef getClassName(const RecordDecl *RD);

  /// \brief Get vtable name for the given Class.
  StringRef getVTableName(const CXXRecordDecl *Decl);

  /// \brief Get line number for the location. If location is invalid
  /// then use current location.
  unsigned getLineNumber(SourceLocation Loc);

  /// \brief Get column number for the location. If location is
  /// invalid then use current location.
  /// \param Force  Assume DebugColumnInfo option is true.
  unsigned getColumnNumber(SourceLocation Loc, bool Force=false);

  /// \brief Collect various properties of a FunctionDecl.
  /// \param GD  A GlobalDecl whose getDecl() must return a FunctionDecl.
  void collectFunctionDeclProps(GlobalDecl GD, llvm::DIFile Unit,
                                StringRef &Name, StringRef &LinkageName,
                                llvm::MDScope *&FDContext,
                                llvm::DIArray &TParamsArray, unsigned &Flags);

  /// \brief Collect various properties of a VarDecl.
  void collectVarDeclProps(const VarDecl *VD, llvm::DIFile &Unit,
                           unsigned &LineNo, QualType &T, StringRef &Name,
                           StringRef &LinkageName, llvm::MDScope *&VDContext);

  /// \brief Allocate a copy of \p A using the DebugInfoNames allocator
  /// and return a reference to it. If multiple arguments are given the strings
  /// are concatenated.
  StringRef internString(StringRef A, StringRef B = StringRef()) {
    char *Data = DebugInfoNames.Allocate<char>(A.size() + B.size());
    std::memcpy(Data, A.data(), A.size());
    std::memcpy(Data + A.size(), B.data(), B.size());
    return StringRef(Data, A.size() + B.size());
  }
};

/// \brief A scoped helper to set the current debug location to the specified
/// location or preferred location of the specified Expr.
class ApplyDebugLocation {
private:
  void init(SourceLocation TemporaryLocation, bool DefaultToEmpty = false);
  ApplyDebugLocation(CodeGenFunction &CGF, bool DefaultToEmpty,
                     SourceLocation TemporaryLocation);

  llvm::DebugLoc OriginalLocation;
  CodeGenFunction &CGF;
public:

  /// \brief Set the location to the (valid) TemporaryLocation.
  ApplyDebugLocation(CodeGenFunction &CGF, SourceLocation TemporaryLocation);
  ApplyDebugLocation(CodeGenFunction &CGF, const Expr *E);
  ApplyDebugLocation(CodeGenFunction &CGF, llvm::DebugLoc Loc);

  ~ApplyDebugLocation();

  /// \brief Apply TemporaryLocation if it is valid. Otherwise switch to an
  /// artificial debug location that has a valid scope, but no line information.
  ///
  /// Artificial locations are useful when emitting compiler-generated helper
  /// functions that have no source location associated with them. The DWARF
  /// specification allows the compiler to use the special line number 0 to
  /// indicate code that can not be attributed to any source location. Note that
  /// passing an empty SourceLocation to CGDebugInfo::setLocation() will result
  /// in the last valid location being reused.
  static ApplyDebugLocation CreateArtificial(CodeGenFunction &CGF) {
    return ApplyDebugLocation(CGF, false, SourceLocation());
  }
  /// \brief Apply TemporaryLocation if it is valid. Otherwise switch to an
  /// artificial debug location that has a valid scope, but no line information.
  static ApplyDebugLocation CreateDefaultArtificial(CodeGenFunction &CGF,
                                             SourceLocation TemporaryLocation) {
    return ApplyDebugLocation(CGF, false, TemporaryLocation);
  }

  /// \brief Set the IRBuilder to not attach debug locations.  Note that passing
  /// an empty SourceLocation to CGDebugInfo::setLocation() will result in the
  /// last valid location being reused.  Note that all instructions that do not
  /// have a location at the beginning of a function are counted towards to
  /// funciton prologue.
  static ApplyDebugLocation CreateEmpty(CodeGenFunction &CGF) {
    return ApplyDebugLocation(CGF, true, SourceLocation());
  }

  /// \brief Apply TemporaryLocation if it is valid. Otherwise set the IRBuilder
  /// to not attach debug locations.
  static ApplyDebugLocation CreateDefaultEmpty(CodeGenFunction &CGF,
                                             SourceLocation TemporaryLocation) {
    return ApplyDebugLocation(CGF, true, TemporaryLocation);
  }

};


} // namespace CodeGen
} // namespace clang


#endif