Mangle.h

Go to the documentation of this file.

//===--- Mangle.h - Mangle C++ Names ----------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Defines the C++ name mangling interface.
//
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_CLANG_AST_MANGLE_H
#define LLVM_CLANG_AST_MANGLE_H
 
#include "clang/AST/Decl.h"
#include "clang/AST/GlobalDecl.h"
#include "clang/AST/Type.h"
#include "clang/Basic/ABI.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/Support/Casting.h"
#include <optional>
 
namespace llvm {
class raw_ostream;
}
 
namespace clang {
class ASTContext;
class BlockDecl;
class CXXConstructorDecl;
class CXXDestructorDecl;
class CXXMethodDecl;
class FunctionDecl;
struct MethodVFTableLocation;
class NamedDecl;
class ObjCMethodDecl;
class StringLiteral;
struct ThisAdjustment;
struct ThunkInfo;
class VarDecl;
 
/// Extract mangling function name from MangleContext such that swift can call
/// it to prepare for ObjCDirect in swift.
/// Produces the mangling:
///   \01-[ClassName(Category) method:arg1:arg2:]
/// Or, if useDirectABI is true (for Direct ABI):
///   -[ClassName(Category) method:arg1:arg2:]D
void mangleObjCMethodName(raw_ostream &OS, bool includePrefixByte,
                          bool isInstanceMethod, StringRef ClassName,
                          std::optional<StringRef> CategoryName,
                          StringRef MethodName, bool useDirectABI);
 
/// MangleContext - Context for tracking state which persists across multiple
/// calls to the C++ name mangler.
class MangleContext {
public:
  enum ManglerKind { MK_Itanium, MK_Microsoft };
 
private:
  virtual void anchor();
 
  ASTContext &Context;
  DiagnosticsEngine &Diags;
  const ManglerKind Kind;
  /// For aux target. If true, uses mangling number for aux target from
  /// ASTContext.
  bool IsAux = false;
 
  llvm::DenseMap<const BlockDecl *, unsigned> GlobalBlockIds;
  llvm::DenseMap<const BlockDecl *, unsigned> LocalBlockIds;
  llvm::DenseMap<const NamedDecl *, uint64_t> AnonStructIds;
  llvm::DenseMap<const FunctionDecl *, unsigned> FuncAnonStructSize;
 
public:
  ManglerKind getKind() const { return Kind; }
 
  bool isAux() const { return IsAux; }
 
  explicit MangleContext(ASTContext &Context, DiagnosticsEngine &Diags,
                         ManglerKind Kind, bool IsAux = false)
      : Context(Context), Diags(Diags), Kind(Kind), IsAux(IsAux) {}
 
  virtual ~MangleContext() {}
 
  ASTContext &getASTContext() const { return Context; }
 
  DiagnosticsEngine &getDiags() const { return Diags; }
 
  virtual void startNewFunction() { LocalBlockIds.clear(); }
 
  unsigned getBlockId(const BlockDecl *BD, bool Local) {
    llvm::DenseMap<const BlockDecl *, unsigned> &BlockIds =
        Local ? LocalBlockIds : GlobalBlockIds;
    std::pair<llvm::DenseMap<const BlockDecl *, unsigned>::iterator, bool>
        Result = BlockIds.insert(std::make_pair(BD, BlockIds.size()));
    return Result.first->second;
  }
 
  uint64_t getAnonymousStructId(const NamedDecl *D,
                                const FunctionDecl *FD = nullptr) {
    auto FindResult = AnonStructIds.find(D);
    if (FindResult != AnonStructIds.end())
      return FindResult->second;
 
    // If FunctionDecl is passed in, the anonymous structID will be per-function
    // based.
    unsigned Id = FD ? FuncAnonStructSize[FD]++ : AnonStructIds.size();
    std::pair<llvm::DenseMap<const NamedDecl *, uint64_t>::iterator, bool>
        Result = AnonStructIds.insert(std::make_pair(D, Id));
    return Result.first->second;
  }
 
  uint64_t getAnonymousStructIdForDebugInfo(const NamedDecl *D) {
    llvm::DenseMap<const NamedDecl *, uint64_t>::iterator Result =
        AnonStructIds.find(D);
    // The decl should already be inserted, but return 0 in case it is not.
    if (Result == AnonStructIds.end())
      return 0;
    return Result->second;
  }
 
  virtual std::string getLambdaString(const CXXRecordDecl *Lambda) = 0;
 
  /// @name Mangler Entry Points
  /// @{
 
  bool shouldMangleDeclName(const NamedDecl *D);
  virtual bool shouldMangleCXXName(const NamedDecl *D) = 0;
  virtual bool shouldMangleStringLiteral(const StringLiteral *SL) = 0;
 
  /// Return true if \p FD's body contains a direct call back to the symbol it
  /// links as, through an asm label or a __builtin_* alias (PR9614 / glibc's
  /// btowc pattern).  An available_externally body of such a function is not a
  /// valid stand-in for the real implementation and should be dropped before
  /// codegen.  The check keys off the mangled/asm name, hence it lives on
  /// MangleContext.
  bool isTriviallyRecursive(const FunctionDecl *FD);
 
  virtual bool isUniqueInternalLinkageDecl(const NamedDecl *ND) {
    return false;
  }
 
  virtual void needsUniqueInternalLinkageNames() {}
 
  // FIXME: consider replacing raw_ostream & with something like SmallString &.
  void mangleName(GlobalDecl GD, raw_ostream &);
  virtual void mangleCXXName(GlobalDecl GD, raw_ostream &) = 0;
  virtual void mangleThunk(const CXXMethodDecl *MD, const ThunkInfo &Thunk,
                           bool ElideOverrideInfo, raw_ostream &) = 0;
  virtual void mangleCXXDtorThunk(const CXXDestructorDecl *DD, CXXDtorType Type,
                                  const ThunkInfo &Thunk,
                                  bool ElideOverrideInfo, raw_ostream &) = 0;
  virtual void mangleReferenceTemporary(const VarDecl *D,
                                        unsigned ManglingNumber,
                                        raw_ostream &) = 0;
  virtual void mangleCXXVTable(const CXXRecordDecl *RD, raw_ostream &) = 0;
  virtual void mangleCXXRTTI(QualType T, raw_ostream &) = 0;
  virtual void mangleCXXRTTIName(QualType T, raw_ostream &,
                                 bool NormalizeIntegers = false) = 0;
  virtual void mangleStringLiteral(const StringLiteral *SL, raw_ostream &) = 0;
  virtual void mangleMSGuidDecl(const MSGuidDecl *GD, raw_ostream &) const;
 
  void mangleGlobalBlock(const BlockDecl *BD, const NamedDecl *ID,
                         raw_ostream &Out);
  void mangleCtorBlock(const CXXConstructorDecl *CD, CXXCtorType CT,
                       const BlockDecl *BD, raw_ostream &Out);
  void mangleDtorBlock(const CXXDestructorDecl *CD, CXXDtorType DT,
                       const BlockDecl *BD, raw_ostream &Out);
  void mangleBlock(const DeclContext *DC, const BlockDecl *BD,
                   raw_ostream &Out);
 
  void mangleObjCMethodName(const ObjCMethodDecl *MD, raw_ostream &OS,
                            bool includePrefixByte = true,
                            bool includeCategoryNamespace = true,
                            bool useDirectABI = false) const;
  void mangleObjCMethodNameAsSourceName(const ObjCMethodDecl *MD,
                                        raw_ostream &) const;
 
  virtual void mangleStaticGuardVariable(const VarDecl *D, raw_ostream &) = 0;
 
  virtual void mangleDynamicInitializer(const VarDecl *D, raw_ostream &) = 0;
 
  virtual void mangleDynamicAtExitDestructor(const VarDecl *D,
                                             raw_ostream &) = 0;
 
  virtual void mangleSEHFilterExpression(GlobalDecl EnclosingDecl,
                                         raw_ostream &Out) = 0;
 
  virtual void mangleSEHFinallyBlock(GlobalDecl EnclosingDecl,
                                     raw_ostream &Out) = 0;
 
  /// Generates a unique string for an externally visible type for use with TBAA
  /// or type uniquing.
  /// TODO: Extend this to internal types by generating names that are unique
  /// across translation units so it can be used with LTO.
  virtual void mangleCanonicalTypeName(QualType T, raw_ostream &,
                                       bool NormalizeIntegers = false) = 0;
 
  /// @}
};
 
class ItaniumMangleContext : public MangleContext {
public:
  using DiscriminatorOverrideTy = UnsignedOrNone (*)(ASTContext &,
                                                     const NamedDecl *);
  explicit ItaniumMangleContext(ASTContext &C, DiagnosticsEngine &D,
                                bool IsAux = false)
      : MangleContext(C, D, MK_Itanium, IsAux) {}
 
  virtual void mangleCXXVTT(const CXXRecordDecl *RD, raw_ostream &) = 0;
  virtual void mangleCXXCtorVTable(const CXXRecordDecl *RD, int64_t Offset,
                                   const CXXRecordDecl *Type,
                                   raw_ostream &) = 0;
  virtual void mangleItaniumThreadLocalInit(const VarDecl *D,
                                            raw_ostream &) = 0;
  virtual void mangleItaniumThreadLocalWrapper(const VarDecl *D,
                                               raw_ostream &) = 0;
 
  virtual void mangleCXXCtorComdat(const CXXConstructorDecl *D,
                                   raw_ostream &) = 0;
  virtual void mangleCXXDtorComdat(const CXXDestructorDecl *D,
                                   raw_ostream &) = 0;
 
  virtual void mangleLambdaSig(const CXXRecordDecl *Lambda, raw_ostream &) = 0;
 
  virtual void mangleDynamicStermFinalizer(const VarDecl *D, raw_ostream &) = 0;
 
  virtual void mangleModuleInitializer(const Module *Module, raw_ostream &) = 0;
 
  // This has to live here, otherwise the CXXNameMangler won't have access to
  // it.
  virtual DiscriminatorOverrideTy getDiscriminatorOverride() const = 0;
  static bool classof(const MangleContext *C) {
    return C->getKind() == MK_Itanium;
  }
 
  static ItaniumMangleContext *
  create(ASTContext &Context, DiagnosticsEngine &Diags, bool IsAux = false);
  static ItaniumMangleContext *create(ASTContext &Context,
                                      DiagnosticsEngine &Diags,
                                      DiscriminatorOverrideTy Discriminator,
                                      bool IsAux = false);
};
 
class MicrosoftMangleContext : public MangleContext {
public:
  explicit MicrosoftMangleContext(ASTContext &C, DiagnosticsEngine &D,
                                  bool IsAux = false)
      : MangleContext(C, D, MK_Microsoft, IsAux) {}
 
  /// Mangle vftable symbols.  Only a subset of the bases along the path
  /// to the vftable are included in the name.  It's up to the caller to pick
  /// them correctly.
  virtual void mangleCXXVFTable(const CXXRecordDecl *Derived,
                                ArrayRef<const CXXRecordDecl *> BasePath,
                                raw_ostream &Out) = 0;
 
  /// Mangle vbtable symbols.  Only a subset of the bases along the path
  /// to the vbtable are included in the name.  It's up to the caller to pick
  /// them correctly.
  virtual void mangleCXXVBTable(const CXXRecordDecl *Derived,
                                ArrayRef<const CXXRecordDecl *> BasePath,
                                raw_ostream &Out) = 0;
 
  virtual void mangleThreadSafeStaticGuardVariable(const VarDecl *VD,
                                                   unsigned GuardNum,
                                                   raw_ostream &Out) = 0;
 
  virtual void mangleVirtualMemPtrThunk(const CXXMethodDecl *MD,
                                        const MethodVFTableLocation &ML,
                                        raw_ostream &Out) = 0;
 
  virtual void mangleCXXVirtualDisplacementMap(const CXXRecordDecl *SrcRD,
                                               const CXXRecordDecl *DstRD,
                                               raw_ostream &Out) = 0;
 
  virtual void mangleCXXThrowInfo(QualType T, bool IsConst, bool IsVolatile,
                                  bool IsUnaligned, uint32_t NumEntries,
                                  raw_ostream &Out) = 0;
 
  virtual void mangleCXXCatchableTypeArray(QualType T, uint32_t NumEntries,
                                           raw_ostream &Out) = 0;
 
  virtual void mangleCXXCatchableType(QualType T, const CXXConstructorDecl *CD,
                                      CXXCtorType CT, uint32_t Size,
                                      uint32_t NVOffset, int32_t VBPtrOffset,
                                      uint32_t VBIndex, raw_ostream &Out) = 0;
 
  virtual void mangleCXXRTTIBaseClassDescriptor(
      const CXXRecordDecl *Derived, uint32_t NVOffset, int32_t VBPtrOffset,
      uint32_t VBTableOffset, uint32_t Flags, raw_ostream &Out) = 0;
 
  virtual void mangleCXXRTTIBaseClassArray(const CXXRecordDecl *Derived,
                                           raw_ostream &Out) = 0;
  virtual void
  mangleCXXRTTIClassHierarchyDescriptor(const CXXRecordDecl *Derived,
                                        raw_ostream &Out) = 0;
 
  virtual void
  mangleCXXRTTICompleteObjectLocator(const CXXRecordDecl *Derived,
                                     ArrayRef<const CXXRecordDecl *> BasePath,
                                     raw_ostream &Out) = 0;
 
  static bool classof(const MangleContext *C) {
    return C->getKind() == MK_Microsoft;
  }
 
  static MicrosoftMangleContext *
  create(ASTContext &Context, DiagnosticsEngine &Diags, bool IsAux = false);
};
 
class ASTNameGenerator {
public:
  explicit ASTNameGenerator(ASTContext &Ctx);
  ~ASTNameGenerator();
 
  /// Writes name for \p D to \p OS.
  /// \returns true on failure, false on success.
  bool writeName(const Decl *D, raw_ostream &OS);
 
  /// \returns name for \p D
  std::string getName(const Decl *D);
 
  /// \returns all applicable mangled names.
  /// For example C++ constructors/destructors can have multiple.
  std::vector<std::string> getAllManglings(const Decl *D);
 
private:
  class Implementation;
  std::unique_ptr<Implementation> Impl;
};
 
/// Constants used by LLDB for mangling.
struct LLDBManglingABI {
  static constexpr llvm::StringLiteral FunctionLabelPrefix = "$__lldb_func:";
};
} // namespace clang
 
#endif