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//===--- MacroInfo.h - Information about #defined identifiers ---*- C++ -*-===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
/// \file
/// \brief Defines the clang::MacroInfo and clang::MacroDirective classes.
#include "clang/Lex/Token.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/Allocator.h"
#include <cassert>
namespace clang {
class Preprocessor;
/// \brief Encapsulates the data about a macro definition (e.g. its tokens).
/// There's an instance of this class for every #define.
class MacroInfo {
// State set when the macro is defined.
/// \brief The location the macro is defined.
SourceLocation Location;
/// \brief The location of the last token in the macro.
SourceLocation EndLocation;
/// \brief The list of arguments for a function-like macro.
/// ArgumentList points to the first of NumArguments pointers.
/// This can be empty, for, e.g. "#define X()". In a C99-style variadic macro, this
/// includes the \c __VA_ARGS__ identifier on the list.
IdentifierInfo **ArgumentList;
/// \see ArgumentList
unsigned NumArguments;
/// \brief This is the list of tokens that the macro is defined to.
SmallVector<Token, 8> ReplacementTokens;
/// \brief Length in characters of the macro definition.
mutable unsigned DefinitionLength;
mutable bool IsDefinitionLengthCached : 1;
/// \brief True if this macro is function-like, false if it is object-like.
bool IsFunctionLike : 1;
/// \brief True if this macro is of the form "#define X(...)" or
/// "#define X(Y,Z,...)".
/// The __VA_ARGS__ token should be replaced with the contents of "..." in an
/// invocation.
bool IsC99Varargs : 1;
/// \brief True if this macro is of the form "#define X(a...)".
/// The "a" identifier in the replacement list will be replaced with all arguments
/// of the macro starting with the specified one.
bool IsGNUVarargs : 1;
/// \brief True if this macro requires processing before expansion.
/// This is the case for builtin macros such as __LINE__, so long as they have
/// not been redefined, but not for regular predefined macros from the "<built-in>"
/// memory buffer (see Preprocessing::getPredefinesFileID).
bool IsBuiltinMacro : 1;
/// \brief Whether this macro contains the sequence ", ## __VA_ARGS__"
bool HasCommaPasting : 1;
// State that changes as the macro is used.
/// \brief True if we have started an expansion of this macro already.
/// This disables recursive expansion, which would be quite bad for things
/// like \#define A A.
bool IsDisabled : 1;
/// \brief True if this macro is either defined in the main file and has
/// been used, or if it is not defined in the main file.
/// This is used to emit -Wunused-macros diagnostics.
bool IsUsed : 1;
/// \brief True if this macro can be redefined without emitting a warning.
bool IsAllowRedefinitionsWithoutWarning : 1;
/// \brief Must warn if the macro is unused at the end of translation unit.
bool IsWarnIfUnused : 1;
/// \brief Whether this macro info was loaded from an AST file.
unsigned FromASTFile : 1;
/// \brief Whether this macro was used as header guard.
bool UsedForHeaderGuard : 1;
~MacroInfo() {
assert(!ArgumentList && "Didn't call destroy before dtor!");
MacroInfo(SourceLocation DefLoc);
/// \brief Free the argument list of the macro.
/// This restores this MacroInfo to a state where it can be reused for other
/// devious purposes.
void FreeArgumentList() {
ArgumentList = nullptr;
NumArguments = 0;
/// \brief Destroy this MacroInfo object.
void Destroy() {
/// \brief Return the location that the macro was defined at.
SourceLocation getDefinitionLoc() const { return Location; }
/// \brief Set the location of the last token in the macro.
void setDefinitionEndLoc(SourceLocation EndLoc) { EndLocation = EndLoc; }
/// \brief Return the location of the last token in the macro.
SourceLocation getDefinitionEndLoc() const { return EndLocation; }
/// \brief Get length in characters of the macro definition.
unsigned getDefinitionLength(SourceManager &SM) const {
if (IsDefinitionLengthCached)
return DefinitionLength;
return getDefinitionLengthSlow(SM);
/// \brief Return true if the specified macro definition is equal to
/// this macro in spelling, arguments, and whitespace.
/// \param Syntactically if true, the macro definitions can be identical even
/// if they use different identifiers for the function macro parameters.
/// Otherwise the comparison is lexical and this implements the rules in
/// C99 6.10.3.
bool isIdenticalTo(const MacroInfo &Other, Preprocessor &PP,
bool Syntactically) const;
/// \brief Set or clear the isBuiltinMacro flag.
void setIsBuiltinMacro(bool Val = true) {
IsBuiltinMacro = Val;
/// \brief Set the value of the IsUsed flag.
void setIsUsed(bool Val) {
IsUsed = Val;
/// \brief Set the value of the IsAllowRedefinitionsWithoutWarning flag.
void setIsAllowRedefinitionsWithoutWarning(bool Val) {
IsAllowRedefinitionsWithoutWarning = Val;
/// \brief Set the value of the IsWarnIfUnused flag.
void setIsWarnIfUnused(bool val) {
IsWarnIfUnused = val;
/// \brief Set the specified list of identifiers as the argument list for
/// this macro.
void setArgumentList(IdentifierInfo* const *List, unsigned NumArgs,
llvm::BumpPtrAllocator &PPAllocator) {
assert(ArgumentList == nullptr && NumArguments == 0 &&
"Argument list already set!");
if (NumArgs == 0) return;
NumArguments = NumArgs;
ArgumentList = PPAllocator.Allocate<IdentifierInfo*>(NumArgs);
for (unsigned i = 0; i != NumArgs; ++i)
ArgumentList[i] = List[i];
/// Arguments - The list of arguments for a function-like macro. This can be
/// empty, for, e.g. "#define X()".
typedef IdentifierInfo* const *arg_iterator;
bool arg_empty() const { return NumArguments == 0; }
arg_iterator arg_begin() const { return ArgumentList; }
arg_iterator arg_end() const { return ArgumentList+NumArguments; }
unsigned getNumArgs() const { return NumArguments; }
/// \brief Return the argument number of the specified identifier,
/// or -1 if the identifier is not a formal argument identifier.
int getArgumentNum(IdentifierInfo *Arg) const {
for (arg_iterator I = arg_begin(), E = arg_end(); I != E; ++I)
if (*I == Arg) return I-arg_begin();
return -1;
/// Function/Object-likeness. Keep track of whether this macro has formal
/// parameters.
void setIsFunctionLike() { IsFunctionLike = true; }
bool isFunctionLike() const { return IsFunctionLike; }
bool isObjectLike() const { return !IsFunctionLike; }
/// Varargs querying methods. This can only be set for function-like macros.
void setIsC99Varargs() { IsC99Varargs = true; }
void setIsGNUVarargs() { IsGNUVarargs = true; }
bool isC99Varargs() const { return IsC99Varargs; }
bool isGNUVarargs() const { return IsGNUVarargs; }
bool isVariadic() const { return IsC99Varargs | IsGNUVarargs; }
/// \brief Return true if this macro requires processing before expansion.
/// This is true only for builtin macro, such as \__LINE__, whose values
/// are not given by fixed textual expansions. Regular predefined macros
/// from the "<built-in>" buffer are not reported as builtins by this
/// function.
bool isBuiltinMacro() const { return IsBuiltinMacro; }
bool hasCommaPasting() const { return HasCommaPasting; }
void setHasCommaPasting() { HasCommaPasting = true; }
/// \brief Return false if this macro is defined in the main file and has
/// not yet been used.
bool isUsed() const { return IsUsed; }
/// \brief Return true if this macro can be redefined without warning.
bool isAllowRedefinitionsWithoutWarning() const {
return IsAllowRedefinitionsWithoutWarning;
/// \brief Return true if we should emit a warning if the macro is unused.
bool isWarnIfUnused() const {
return IsWarnIfUnused;
/// \brief Return the number of tokens that this macro expands to.
unsigned getNumTokens() const {
return ReplacementTokens.size();
const Token &getReplacementToken(unsigned Tok) const {
assert(Tok < ReplacementTokens.size() && "Invalid token #");
return ReplacementTokens[Tok];
typedef SmallVectorImpl<Token>::const_iterator tokens_iterator;
tokens_iterator tokens_begin() const { return ReplacementTokens.begin(); }
tokens_iterator tokens_end() const { return ReplacementTokens.end(); }
bool tokens_empty() const { return ReplacementTokens.empty(); }
/// \brief Add the specified token to the replacement text for the macro.
void AddTokenToBody(const Token &Tok) {
assert(!IsDefinitionLengthCached &&
"Changing replacement tokens after definition length got calculated");
/// \brief Return true if this macro is enabled.
/// In other words, that we are not currently in an expansion of this macro.
bool isEnabled() const { return !IsDisabled; }
void EnableMacro() {
assert(IsDisabled && "Cannot enable an already-enabled macro!");
IsDisabled = false;
void DisableMacro() {
assert(!IsDisabled && "Cannot disable an already-disabled macro!");
IsDisabled = true;
/// \brief Determine whether this macro info came from an AST file (such as
/// a precompiled header or module) rather than having been parsed.
bool isFromASTFile() const { return FromASTFile; }
/// \brief Determine whether this macro was used for a header guard.
bool isUsedForHeaderGuard() const { return UsedForHeaderGuard; }
void setUsedForHeaderGuard(bool Val) { UsedForHeaderGuard = Val; }
/// \brief Retrieve the global ID of the module that owns this particular
/// macro info.
unsigned getOwningModuleID() const {
if (isFromASTFile())
return *(const unsigned*)(this+1);
return 0;
void dump() const;
unsigned getDefinitionLengthSlow(SourceManager &SM) const;
void setOwningModuleID(unsigned ID) {
*(unsigned*)(this+1) = ID;
friend class Preprocessor;
class DefMacroDirective;
/// \brief Encapsulates changes to the "macros namespace" (the location where
/// the macro name became active, the location where it was undefined, etc.).
/// MacroDirectives, associated with an identifier, are used to model the macro
/// history. Usually a macro definition (MacroInfo) is where a macro name
/// becomes active (MacroDirective) but modules can have their own macro
/// history, separate from the local (current translation unit) macro history.
/// For example, if "@import A;" imports macro FOO, there will be a new local
/// MacroDirective created to indicate that "FOO" became active at the import
/// location. Module "A" itself will contain another MacroDirective in its macro
/// history (at the point of the definition of FOO) and both MacroDirectives
/// will point to the same MacroInfo object.
class MacroDirective {
enum Kind {
/// \brief Previous macro directive for the same identifier, or NULL.
MacroDirective *Previous;
SourceLocation Loc;
/// \brief MacroDirective kind.
unsigned MDKind : 2;
/// \brief True if the macro directive was loaded from a PCH file.
bool IsFromPCH : 1;
// Used by DefMacroDirective -----------------------------------------------//
/// \brief True if this macro was imported from a module.
bool IsImported : 1;
/// \brief Whether the definition of this macro is ambiguous, due to
/// multiple definitions coming in from multiple modules.
bool IsAmbiguous : 1;
// Used by VisibilityMacroDirective ----------------------------------------//
/// \brief Whether the macro has public visibility (when described in a
/// module).
bool IsPublic : 1;
MacroDirective(Kind K, SourceLocation Loc)
: Previous(nullptr), Loc(Loc), MDKind(K), IsFromPCH(false),
IsImported(false), IsAmbiguous(false),
IsPublic(true) {
Kind getKind() const { return Kind(MDKind); }
SourceLocation getLocation() const { return Loc; }
/// \brief Set previous definition of the macro with the same name.
void setPrevious(MacroDirective *Prev) {
Previous = Prev;
/// \brief Get previous definition of the macro with the same name.
const MacroDirective *getPrevious() const { return Previous; }
/// \brief Get previous definition of the macro with the same name.
MacroDirective *getPrevious() { return Previous; }
/// \brief Return true if the macro directive was loaded from a PCH file.
bool isFromPCH() const { return IsFromPCH; }
void setIsFromPCH() { IsFromPCH = true; }
class DefInfo {
DefMacroDirective *DefDirective;
SourceLocation UndefLoc;
bool IsPublic;
DefInfo() : DefDirective(nullptr) { }
DefInfo(DefMacroDirective *DefDirective, SourceLocation UndefLoc,
bool isPublic)
: DefDirective(DefDirective), UndefLoc(UndefLoc), IsPublic(isPublic) { }
const DefMacroDirective *getDirective() const { return DefDirective; }
DefMacroDirective *getDirective() { return DefDirective; }
inline SourceLocation getLocation() const;
inline MacroInfo *getMacroInfo();
const MacroInfo *getMacroInfo() const {
return const_cast<DefInfo*>(this)->getMacroInfo();
SourceLocation getUndefLocation() const { return UndefLoc; }
bool isUndefined() const { return UndefLoc.isValid(); }
bool isPublic() const { return IsPublic; }
bool isValid() const { return DefDirective != nullptr; }
bool isInvalid() const { return !isValid(); }
LLVM_EXPLICIT operator bool() const { return isValid(); }
inline DefInfo getPreviousDefinition();
const DefInfo getPreviousDefinition() const {
return const_cast<DefInfo*>(this)->getPreviousDefinition();
/// \brief Traverses the macro directives history and returns the next
/// macro definition directive along with info about its undefined location
/// (if there is one) and if it is public or private.
DefInfo getDefinition();
const DefInfo getDefinition() const {
return const_cast<MacroDirective*>(this)->getDefinition();
bool isDefined() const {
if (const DefInfo Def = getDefinition())
return !Def.isUndefined();
return false;
const MacroInfo *getMacroInfo() const {
return getDefinition().getMacroInfo();
MacroInfo *getMacroInfo() {
return getDefinition().getMacroInfo();
/// \brief Find macro definition active in the specified source location. If
/// this macro was not defined there, return NULL.
const DefInfo findDirectiveAtLoc(SourceLocation L, SourceManager &SM) const;
void dump() const;
static bool classof(const MacroDirective *) { return true; }
/// \brief A directive for a defined macro or a macro imported from a module.
class DefMacroDirective : public MacroDirective {
MacroInfo *Info;
explicit DefMacroDirective(MacroInfo *MI)
: MacroDirective(MD_Define, MI->getDefinitionLoc()), Info(MI) {
assert(MI && "MacroInfo is null");
DefMacroDirective(MacroInfo *MI, SourceLocation Loc, bool isImported)
: MacroDirective(MD_Define, Loc), Info(MI) {
assert(MI && "MacroInfo is null");
IsImported = isImported;
/// \brief The data for the macro definition.
const MacroInfo *getInfo() const { return Info; }
MacroInfo *getInfo() { return Info; }
/// \brief True if this macro was imported from a module.
bool isImported() const { return IsImported; }
/// \brief Determine whether this macro definition is ambiguous with
/// other macro definitions.
bool isAmbiguous() const { return IsAmbiguous; }
/// \brief Set whether this macro definition is ambiguous.
void setAmbiguous(bool Val) { IsAmbiguous = Val; }
static bool classof(const MacroDirective *MD) {
return MD->getKind() == MD_Define;
static bool classof(const DefMacroDirective *) { return true; }
/// \brief A directive for an undefined macro.
class UndefMacroDirective : public MacroDirective {
explicit UndefMacroDirective(SourceLocation UndefLoc)
: MacroDirective(MD_Undefine, UndefLoc) {
assert(UndefLoc.isValid() && "Invalid UndefLoc!");
static bool classof(const MacroDirective *MD) {
return MD->getKind() == MD_Undefine;
static bool classof(const UndefMacroDirective *) { return true; }
/// \brief A directive for setting the module visibility of a macro.
class VisibilityMacroDirective : public MacroDirective {
explicit VisibilityMacroDirective(SourceLocation Loc, bool Public)
: MacroDirective(MD_Visibility, Loc) {
IsPublic = Public;
/// \brief Determine whether this macro is part of the public API of its
/// module.
bool isPublic() const { return IsPublic; }
static bool classof(const MacroDirective *MD) {
return MD->getKind() == MD_Visibility;
static bool classof(const VisibilityMacroDirective *) { return true; }
inline SourceLocation MacroDirective::DefInfo::getLocation() const {
if (isInvalid())
return SourceLocation();
return DefDirective->getLocation();
inline MacroInfo *MacroDirective::DefInfo::getMacroInfo() {
if (isInvalid())
return nullptr;
return DefDirective->getInfo();
inline MacroDirective::DefInfo
MacroDirective::DefInfo::getPreviousDefinition() {
if (isInvalid() || DefDirective->getPrevious() == nullptr)
return DefInfo();
return DefDirective->getPrevious()->getDefinition();
} // end namespace clang