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//===--- MacroExpansion.cpp - Top level Macro Expansion -------------------===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
// This file implements the top level handling of macro expasion for the
// preprocessor.
#include "clang/Lex/Preprocessor.h"
#include "MacroArgs.h"
#include "clang/Lex/MacroInfo.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/FileManager.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Lex/LexDiagnostic.h"
#include "clang/Lex/CodeCompletionHandler.h"
#include "clang/Lex/ExternalPreprocessorSource.h"
#include "clang/Lex/LiteralSupport.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Config/llvm-config.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/ErrorHandling.h"
#include <cstdio>
#include <ctime>
using namespace clang;
MacroInfo *Preprocessor::getInfoForMacro(IdentifierInfo *II) const {
assert(II->hasMacroDefinition() && "Identifier is not a macro!");
llvm::DenseMap<IdentifierInfo*, MacroInfo*>::const_iterator Pos
= Macros.find(II);
if (Pos == Macros.end()) {
// Load this macro from the external source.
Pos = Macros.find(II);
assert(Pos != Macros.end() && "Identifier macro info is missing!");
return Pos->second;
/// setMacroInfo - Specify a macro for this identifier.
void Preprocessor::setMacroInfo(IdentifierInfo *II, MacroInfo *MI,
bool LoadedFromAST) {
if (MI) {
Macros[II] = MI;
if (II->isFromAST() && !LoadedFromAST)
} else if (II->hasMacroDefinition()) {
if (II->isFromAST() && !LoadedFromAST)
/// RegisterBuiltinMacro - Register the specified identifier in the identifier
/// table and mark it as a builtin macro to be expanded.
static IdentifierInfo *RegisterBuiltinMacro(Preprocessor &PP, const char *Name){
// Get the identifier.
IdentifierInfo *Id = PP.getIdentifierInfo(Name);
// Mark it as being a macro that is builtin.
MacroInfo *MI = PP.AllocateMacroInfo(SourceLocation());
PP.setMacroInfo(Id, MI);
return Id;
/// RegisterBuiltinMacros - Register builtin macros, such as __LINE__ with the
/// identifier table.
void Preprocessor::RegisterBuiltinMacros() {
Ident__LINE__ = RegisterBuiltinMacro(*this, "__LINE__");
Ident__FILE__ = RegisterBuiltinMacro(*this, "__FILE__");
Ident__DATE__ = RegisterBuiltinMacro(*this, "__DATE__");
Ident__TIME__ = RegisterBuiltinMacro(*this, "__TIME__");
Ident__COUNTER__ = RegisterBuiltinMacro(*this, "__COUNTER__");
Ident_Pragma = RegisterBuiltinMacro(*this, "_Pragma");
// GCC Extensions.
Ident__BASE_FILE__ = RegisterBuiltinMacro(*this, "__BASE_FILE__");
Ident__INCLUDE_LEVEL__ = RegisterBuiltinMacro(*this, "__INCLUDE_LEVEL__");
Ident__TIMESTAMP__ = RegisterBuiltinMacro(*this, "__TIMESTAMP__");
// Clang Extensions.
Ident__has_feature = RegisterBuiltinMacro(*this, "__has_feature");
Ident__has_extension = RegisterBuiltinMacro(*this, "__has_extension");
Ident__has_builtin = RegisterBuiltinMacro(*this, "__has_builtin");
Ident__has_attribute = RegisterBuiltinMacro(*this, "__has_attribute");
Ident__has_include = RegisterBuiltinMacro(*this, "__has_include");
Ident__has_include_next = RegisterBuiltinMacro(*this, "__has_include_next");
Ident__has_warning = RegisterBuiltinMacro(*this, "__has_warning");
// Microsoft Extensions.
if (Features.MicrosoftExt)
Ident__pragma = RegisterBuiltinMacro(*this, "__pragma");
Ident__pragma = 0;
/// isTrivialSingleTokenExpansion - Return true if MI, which has a single token
/// in its expansion, currently expands to that token literally.
static bool isTrivialSingleTokenExpansion(const MacroInfo *MI,
const IdentifierInfo *MacroIdent,
Preprocessor &PP) {
IdentifierInfo *II = MI->getReplacementToken(0).getIdentifierInfo();
// If the token isn't an identifier, it's always literally expanded.
if (II == 0) return true;
// If the information about this identifier is out of date, update it from
// the external source.
if (II->isOutOfDate())
// If the identifier is a macro, and if that macro is enabled, it may be
// expanded so it's not a trivial expansion.
if (II->hasMacroDefinition() && PP.getMacroInfo(II)->isEnabled() &&
// Fast expanding "#define X X" is ok, because X would be disabled.
II != MacroIdent)
return false;
// If this is an object-like macro invocation, it is safe to trivially expand
// it.
if (MI->isObjectLike()) return true;
// If this is a function-like macro invocation, it's safe to trivially expand
// as long as the identifier is not a macro argument.
for (MacroInfo::arg_iterator I = MI->arg_begin(), E = MI->arg_end();
I != E; ++I)
if (*I == II)
return false; // Identifier is a macro argument.
return true;
/// isNextPPTokenLParen - Determine whether the next preprocessor token to be
/// lexed is a '('. If so, consume the token and return true, if not, this
/// method should have no observable side-effect on the lexed tokens.
bool Preprocessor::isNextPPTokenLParen() {
// Do some quick tests for rejection cases.
unsigned Val;
if (CurLexer)
Val = CurLexer->isNextPPTokenLParen();
else if (CurPTHLexer)
Val = CurPTHLexer->isNextPPTokenLParen();
Val = CurTokenLexer->isNextTokenLParen();
if (Val == 2) {
// We have run off the end. If it's a source file we don't
// examine enclosing ones (C99 Otherwise walk up the
// macro stack.
if (CurPPLexer)
return false;
for (unsigned i = IncludeMacroStack.size(); i != 0; --i) {
IncludeStackInfo &Entry = IncludeMacroStack[i-1];
if (Entry.TheLexer)
Val = Entry.TheLexer->isNextPPTokenLParen();
else if (Entry.ThePTHLexer)
Val = Entry.ThePTHLexer->isNextPPTokenLParen();
Val = Entry.TheTokenLexer->isNextTokenLParen();
if (Val != 2)
// Ran off the end of a source file?
if (Entry.ThePPLexer)
return false;
// Okay, if we know that the token is a '(', lex it and return. Otherwise we
// have found something that isn't a '(' or we found the end of the
// translation unit. In either case, return false.
return Val == 1;
/// HandleMacroExpandedIdentifier - If an identifier token is read that is to be
/// expanded as a macro, handle it and return the next token as 'Identifier'.
bool Preprocessor::HandleMacroExpandedIdentifier(Token &Identifier,
MacroInfo *MI) {
// If this is a macro expansion in the "#if !defined(x)" line for the file,
// then the macro could expand to different things in other contexts, we need
// to disable the optimization in this case.
if (CurPPLexer) CurPPLexer->MIOpt.ExpandedMacro();
// If this is a builtin macro, like __LINE__ or _Pragma, handle it specially.
if (MI->isBuiltinMacro()) {
if (Callbacks) Callbacks->MacroExpands(Identifier, MI,
return false;
/// Args - If this is a function-like macro expansion, this contains,
/// for each macro argument, the list of tokens that were provided to the
/// invocation.
MacroArgs *Args = 0;
// Remember where the end of the expansion occurred. For an object-like
// macro, this is the identifier. For a function-like macro, this is the ')'.
SourceLocation ExpansionEnd = Identifier.getLocation();
// If this is a function-like macro, read the arguments.
if (MI->isFunctionLike()) {
// C99 6.10.3p10: If the preprocessing token immediately after the the macro
// name isn't a '(', this macro should not be expanded.
if (!isNextPPTokenLParen())
return true;
// Remember that we are now parsing the arguments to a macro invocation.
// Preprocessor directives used inside macro arguments are not portable, and
// this enables the warning.
InMacroArgs = true;
Args = ReadFunctionLikeMacroArgs(Identifier, MI, ExpansionEnd);
// Finished parsing args.
InMacroArgs = false;
// If there was an error parsing the arguments, bail out.
if (Args == 0) return false;
} else {
// Notice that this macro has been used.
// Remember where the token is expanded.
SourceLocation ExpandLoc = Identifier.getLocation();
if (Callbacks) Callbacks->MacroExpands(Identifier, MI,
SourceRange(ExpandLoc, ExpansionEnd));
// If we started lexing a macro, enter the macro expansion body.
// If this macro expands to no tokens, don't bother to push it onto the
// expansion stack, only to take it right back off.
if (MI->getNumTokens() == 0) {
// No need for arg info.
if (Args) Args->destroy(*this);
// Ignore this macro use, just return the next token in the current
// buffer.
bool HadLeadingSpace = Identifier.hasLeadingSpace();
bool IsAtStartOfLine = Identifier.isAtStartOfLine();
// If the identifier isn't on some OTHER line, inherit the leading
// whitespace/first-on-a-line property of this token. This handles
// stuff like "! XX," -> "! ," and " XX," -> " ,", when XX is
// empty.
if (!Identifier.isAtStartOfLine()) {
if (IsAtStartOfLine) Identifier.setFlag(Token::StartOfLine);
if (HadLeadingSpace) Identifier.setFlag(Token::LeadingSpace);
return false;
} else if (MI->getNumTokens() == 1 &&
isTrivialSingleTokenExpansion(MI, Identifier.getIdentifierInfo(),
*this)) {
// Otherwise, if this macro expands into a single trivially-expanded
// token: expand it now. This handles common cases like
// "#define VAL 42".
// No need for arg info.
if (Args) Args->destroy(*this);
// Propagate the isAtStartOfLine/hasLeadingSpace markers of the macro
// identifier to the expanded token.
bool isAtStartOfLine = Identifier.isAtStartOfLine();
bool hasLeadingSpace = Identifier.hasLeadingSpace();
// Replace the result token.
Identifier = MI->getReplacementToken(0);
// Restore the StartOfLine/LeadingSpace markers.
Identifier.setFlagValue(Token::StartOfLine , isAtStartOfLine);
Identifier.setFlagValue(Token::LeadingSpace, hasLeadingSpace);
// Update the tokens location to include both its expansion and physical
// locations.
SourceLocation Loc =
SourceMgr.createExpansionLoc(Identifier.getLocation(), ExpandLoc,
// If this is a disabled macro or #define X X, we must mark the result as
// unexpandable.
if (IdentifierInfo *NewII = Identifier.getIdentifierInfo()) {
if (MacroInfo *NewMI = getMacroInfo(NewII))
if (!NewMI->isEnabled() || NewMI == MI) {
Diag(Identifier, diag::pp_disabled_macro_expansion);
// Since this is not an identifier token, it can't be macro expanded, so
// we're done.
return false;
// Start expanding the macro.
EnterMacro(Identifier, ExpansionEnd, Args);
// Now that the macro is at the top of the include stack, ask the
// preprocessor to read the next token from it.
return false;
/// ReadFunctionLikeMacroArgs - After reading "MACRO" and knowing that the next
/// token is the '(' of the macro, this method is invoked to read all of the
/// actual arguments specified for the macro invocation. This returns null on
/// error.
MacroArgs *Preprocessor::ReadFunctionLikeMacroArgs(Token &MacroName,
MacroInfo *MI,
SourceLocation &MacroEnd) {
// The number of fixed arguments to parse.
unsigned NumFixedArgsLeft = MI->getNumArgs();
bool isVariadic = MI->isVariadic();
// Outer loop, while there are more arguments, keep reading them.
Token Tok;
// Read arguments as unexpanded tokens. This avoids issues, e.g., where
// an argument value in a macro could expand to ',' or '(' or ')'.
assert( && "Error computing l-paren-ness?");
// ArgTokens - Build up a list of tokens that make up each argument. Each
// argument is separated by an EOF token. Use a SmallVector so we can avoid
// heap allocations in the common case.
SmallVector<Token, 64> ArgTokens;
unsigned NumActuals = 0;
while (Tok.isNot(tok::r_paren)) {
assert(( || &&
"only expect argument separators here");
unsigned ArgTokenStart = ArgTokens.size();
SourceLocation ArgStartLoc = Tok.getLocation();
// C99 6.10.3p11: Keep track of the number of l_parens we have seen. Note
// that we already consumed the first one.
unsigned NumParens = 0;
while (1) {
// Read arguments as unexpanded tokens. This avoids issues, e.g., where
// an argument value in a macro could expand to ',' or '(' or ')'.
if ( || { // "#if f(<eof>" & "#if f(\n"
Diag(MacroName, diag::err_unterm_macro_invoc);
// Do not lose the EOF/EOD. Return it to the client.
MacroName = Tok;
return 0;
} else if ( {
// If we found the ) token, the macro arg list is done.
if (NumParens-- == 0) {
MacroEnd = Tok.getLocation();
} else if ( {
} else if ( && NumParens == 0) {
// Comma ends this argument if there are more fixed arguments expected.
// However, if this is a variadic macro, and this is part of the
// variadic part, then the comma is just an argument token.
if (!isVariadic) break;
if (NumFixedArgsLeft > 1)
} else if ( && !KeepMacroComments) {
// If this is a comment token in the argument list and we're just in
// -C mode (not -CC mode), discard the comment.
} else if (Tok.getIdentifierInfo() != 0) {
// Reading macro arguments can cause macros that we are currently
// expanding from to be popped off the expansion stack. Doing so causes
// them to be reenabled for expansion. Here we record whether any
// identifiers we lex as macro arguments correspond to disabled macros.
// If so, we mark the token as noexpand. This is a subtle aspect of
// C99
if (MacroInfo *MI = getMacroInfo(Tok.getIdentifierInfo()))
if (!MI->isEnabled())
} else if ( {
if (CodeComplete)
MI, NumActuals);
// Don't mark that we reached the code-completion point because the
// parser is going to handle the token and there will be another
// code-completion callback.
// If this was an empty argument list foo(), don't add this as an empty
// argument.
if (ArgTokens.empty() && Tok.getKind() == tok::r_paren)
// If this is not a variadic macro, and too many args were specified, emit
// an error.
if (!isVariadic && NumFixedArgsLeft == 0) {
if (ArgTokens.size() != ArgTokenStart)
ArgStartLoc = ArgTokens[ArgTokenStart].getLocation();
// Emit the diagnostic at the macro name in case there is a missing ).
// Emitting it at the , could be far away from the macro name.
Diag(ArgStartLoc, diag::err_too_many_args_in_macro_invoc);
return 0;
// Empty arguments are standard in C99 and C++0x, and are supported as an extension in
// other modes.
if (ArgTokens.size() == ArgTokenStart && !Features.C99)
Diag(Tok, Features.CPlusPlus0x ?
diag::warn_cxx98_compat_empty_fnmacro_arg :
// Add a marker EOF token to the end of the token list for this argument.
Token EOFTok;
assert(NumFixedArgsLeft != 0 && "Too many arguments parsed");
// Okay, we either found the r_paren. Check to see if we parsed too few
// arguments.
unsigned MinArgsExpected = MI->getNumArgs();
// See MacroArgs instance var for description of this.
bool isVarargsElided = false;
if (NumActuals < MinArgsExpected) {
// There are several cases where too few arguments is ok, handle them now.
if (NumActuals == 0 && MinArgsExpected == 1) {
// #define A(X) or #define A(...) ---> A()
// If there is exactly one argument, and that argument is missing,
// then we have an empty "()" argument empty list. This is fine, even if
// the macro expects one argument (the argument is just empty).
isVarargsElided = MI->isVariadic();
} else if (MI->isVariadic() &&
(NumActuals+1 == MinArgsExpected || // A(x, ...) -> A(X)
(NumActuals == 0 && MinArgsExpected == 2))) {// A(x,...) -> A()
// Varargs where the named vararg parameter is missing: ok as extension.
// #define A(x, ...)
// A("blah")
Diag(Tok, diag::ext_missing_varargs_arg);
// Remember this occurred, allowing us to elide the comma when used for
// cases like:
// #define A(x, foo...) blah(a, ## foo)
// #define B(x, ...) blah(a, ## __VA_ARGS__)
// #define C(...) blah(a, ## __VA_ARGS__)
// A(x) B(x) C()
isVarargsElided = true;
} else {
// Otherwise, emit the error.
Diag(Tok, diag::err_too_few_args_in_macro_invoc);
return 0;
// Add a marker EOF token to the end of the token list for this argument.
SourceLocation EndLoc = Tok.getLocation();
// If we expect two arguments, add both as empty.
if (NumActuals == 0 && MinArgsExpected == 2)
} else if (NumActuals > MinArgsExpected && !MI->isVariadic()) {
// Emit the diagnostic at the macro name in case there is a missing ).
// Emitting it at the , could be far away from the macro name.
Diag(MacroName, diag::err_too_many_args_in_macro_invoc);
return 0;
return MacroArgs::create(MI, ArgTokens, isVarargsElided, *this);
/// \brief Keeps macro expanded tokens for TokenLexers.
/// Works like a stack; a TokenLexer adds the macro expanded tokens that is
/// going to lex in the cache and when it finishes the tokens are removed
/// from the end of the cache.
Token *Preprocessor::cacheMacroExpandedTokens(TokenLexer *tokLexer,
ArrayRef<Token> tokens) {
if (tokens.empty())
return 0;
size_t newIndex = MacroExpandedTokens.size();
bool cacheNeedsToGrow = tokens.size() >
MacroExpandedTokens.append(tokens.begin(), tokens.end());
if (cacheNeedsToGrow) {
// Go through all the TokenLexers whose 'Tokens' pointer points in the
// buffer and update the pointers to the (potential) new buffer array.
for (unsigned i = 0, e = MacroExpandingLexersStack.size(); i != e; ++i) {
TokenLexer *prevLexer;
size_t tokIndex;
llvm::tie(prevLexer, tokIndex) = MacroExpandingLexersStack[i];
prevLexer->Tokens = + tokIndex;
MacroExpandingLexersStack.push_back(std::make_pair(tokLexer, newIndex));
return + newIndex;
void Preprocessor::removeCachedMacroExpandedTokensOfLastLexer() {
size_t tokIndex = MacroExpandingLexersStack.back().second;
assert(tokIndex < MacroExpandedTokens.size());
// Pop the cached macro expanded tokens from the end.
/// ComputeDATE_TIME - Compute the current time, enter it into the specified
/// scratch buffer, then return DATELoc/TIMELoc locations with the position of
/// the identifier tokens inserted.
static void ComputeDATE_TIME(SourceLocation &DATELoc, SourceLocation &TIMELoc,
Preprocessor &PP) {
time_t TT = time(0);
struct tm *TM = localtime(&TT);
static const char * const Months[] = {
char TmpBuffer[32];
#ifdef LLVM_ON_WIN32
sprintf(TmpBuffer, "\"%s %2d %4d\"", Months[TM->tm_mon], TM->tm_mday,
snprintf(TmpBuffer, sizeof(TmpBuffer), "\"%s %2d %4d\"", Months[TM->tm_mon], TM->tm_mday,
Token TmpTok;
PP.CreateString(TmpBuffer, strlen(TmpBuffer), TmpTok);
DATELoc = TmpTok.getLocation();
#ifdef LLVM_ON_WIN32
sprintf(TmpBuffer, "\"%02d:%02d:%02d\"", TM->tm_hour, TM->tm_min, TM->tm_sec);
snprintf(TmpBuffer, sizeof(TmpBuffer), "\"%02d:%02d:%02d\"", TM->tm_hour, TM->tm_min, TM->tm_sec);
PP.CreateString(TmpBuffer, strlen(TmpBuffer), TmpTok);
TIMELoc = TmpTok.getLocation();
/// HasFeature - Return true if we recognize and implement the feature
/// specified by the identifier as a standard language feature.
static bool HasFeature(const Preprocessor &PP, const IdentifierInfo *II) {
const LangOptions &LangOpts = PP.getLangOptions();
return llvm::StringSwitch<bool>(II->getName())
.Case("address_sanitizer", LangOpts.AddressSanitizer)
.Case("attribute_analyzer_noreturn", true)
.Case("attribute_availability", true)
.Case("attribute_cf_returns_not_retained", true)
.Case("attribute_cf_returns_retained", true)
.Case("attribute_deprecated_with_message", true)
.Case("attribute_ext_vector_type", true)
.Case("attribute_ns_returns_not_retained", true)
.Case("attribute_ns_returns_retained", true)
.Case("attribute_ns_consumes_self", true)
.Case("attribute_ns_consumed", true)
.Case("attribute_cf_consumed", true)
.Case("attribute_objc_ivar_unused", true)
.Case("attribute_objc_method_family", true)
.Case("attribute_overloadable", true)
.Case("attribute_unavailable_with_message", true)
.Case("blocks", LangOpts.Blocks)
.Case("cxx_exceptions", LangOpts.Exceptions)
.Case("cxx_rtti", LangOpts.RTTI)
.Case("enumerator_attributes", true)
// Objective-C features
.Case("objc_arr", LangOpts.ObjCAutoRefCount) // FIXME: REMOVE?
.Case("objc_arc", LangOpts.ObjCAutoRefCount)
.Case("objc_arc_weak", LangOpts.ObjCAutoRefCount &&
.Case("objc_fixed_enum", LangOpts.ObjC2)
.Case("objc_instancetype", LangOpts.ObjC2)
.Case("objc_modules", LangOpts.ObjC2 && LangOpts.Modules)
.Case("objc_nonfragile_abi", LangOpts.ObjCNonFragileABI)
.Case("objc_weak_class", LangOpts.ObjCNonFragileABI)
.Case("ownership_holds", true)
.Case("ownership_returns", true)
.Case("ownership_takes", true)
.Case("arc_cf_code_audited", true)
// C11 features
.Case("c_alignas", LangOpts.C11)
.Case("c_atomic", LangOpts.C11)
.Case("c_generic_selections", LangOpts.C11)
.Case("c_static_assert", LangOpts.C11)
// C++0x features
.Case("cxx_access_control_sfinae", LangOpts.CPlusPlus0x)
.Case("cxx_alias_templates", LangOpts.CPlusPlus0x)
.Case("cxx_alignas", LangOpts.CPlusPlus0x)
.Case("cxx_atomic", LangOpts.CPlusPlus0x)
.Case("cxx_attributes", LangOpts.CPlusPlus0x)
.Case("cxx_auto_type", LangOpts.CPlusPlus0x)
//.Case("cxx_constexpr", false);
.Case("cxx_decltype", LangOpts.CPlusPlus0x)
.Case("cxx_default_function_template_args", LangOpts.CPlusPlus0x)
.Case("cxx_defaulted_functions", LangOpts.CPlusPlus0x)
.Case("cxx_delegating_constructors", LangOpts.CPlusPlus0x)
.Case("cxx_deleted_functions", LangOpts.CPlusPlus0x)
.Case("cxx_explicit_conversions", LangOpts.CPlusPlus0x)
//.Case("cxx_generalized_initializers", LangOpts.CPlusPlus0x)
.Case("cxx_implicit_moves", LangOpts.CPlusPlus0x)
//.Case("cxx_inheriting_constructors", false)
.Case("cxx_inline_namespaces", LangOpts.CPlusPlus0x)
//.Case("cxx_lambdas", false)
.Case("cxx_nonstatic_member_init", LangOpts.CPlusPlus0x)
.Case("cxx_noexcept", LangOpts.CPlusPlus0x)
.Case("cxx_nullptr", LangOpts.CPlusPlus0x)
.Case("cxx_override_control", LangOpts.CPlusPlus0x)
.Case("cxx_range_for", LangOpts.CPlusPlus0x)
.Case("cxx_raw_string_literals", LangOpts.CPlusPlus0x)
.Case("cxx_reference_qualified_functions", LangOpts.CPlusPlus0x)
.Case("cxx_rvalue_references", LangOpts.CPlusPlus0x)
.Case("cxx_strong_enums", LangOpts.CPlusPlus0x)
.Case("cxx_static_assert", LangOpts.CPlusPlus0x)
.Case("cxx_trailing_return", LangOpts.CPlusPlus0x)
.Case("cxx_unicode_literals", LangOpts.CPlusPlus0x)
//.Case("cxx_unrestricted_unions", false)
//.Case("cxx_user_literals", false)
.Case("cxx_variadic_templates", LangOpts.CPlusPlus0x)
// Type traits
.Case("has_nothrow_assign", LangOpts.CPlusPlus)
.Case("has_nothrow_copy", LangOpts.CPlusPlus)
.Case("has_nothrow_constructor", LangOpts.CPlusPlus)
.Case("has_trivial_assign", LangOpts.CPlusPlus)
.Case("has_trivial_copy", LangOpts.CPlusPlus)
.Case("has_trivial_constructor", LangOpts.CPlusPlus)
.Case("has_trivial_destructor", LangOpts.CPlusPlus)
.Case("has_virtual_destructor", LangOpts.CPlusPlus)
.Case("is_abstract", LangOpts.CPlusPlus)
.Case("is_base_of", LangOpts.CPlusPlus)
.Case("is_class", LangOpts.CPlusPlus)
.Case("is_convertible_to", LangOpts.CPlusPlus)
// __is_empty is available only if the horrible
// "struct __is_empty" parsing hack hasn't been needed in this
// translation unit. If it has, __is_empty reverts to a normal
// identifier and __has_feature(is_empty) evaluates false.
LangOpts.CPlusPlus &&
!= tok::identifier)
.Case("is_enum", LangOpts.CPlusPlus)
.Case("is_final", LangOpts.CPlusPlus)
.Case("is_literal", LangOpts.CPlusPlus)
.Case("is_standard_layout", LangOpts.CPlusPlus)
// __is_pod is available only if the horrible
// "struct __is_pod" parsing hack hasn't been needed in this
// translation unit. If it has, __is_pod reverts to a normal
// identifier and __has_feature(is_pod) evaluates false.
LangOpts.CPlusPlus &&
!= tok::identifier)
.Case("is_polymorphic", LangOpts.CPlusPlus)
.Case("is_trivial", LangOpts.CPlusPlus)
.Case("is_trivially_copyable", LangOpts.CPlusPlus)
.Case("is_union", LangOpts.CPlusPlus)
.Case("modules", LangOpts.Modules)
.Case("tls", PP.getTargetInfo().isTLSSupported())
.Case("underlying_type", LangOpts.CPlusPlus)
/// HasExtension - Return true if we recognize and implement the feature
/// specified by the identifier, either as an extension or a standard language
/// feature.
static bool HasExtension(const Preprocessor &PP, const IdentifierInfo *II) {
if (HasFeature(PP, II))
return true;
// If the use of an extension results in an error diagnostic, extensions are
// effectively unavailable, so just return false here.
if (PP.getDiagnostics().getExtensionHandlingBehavior() ==
return false;
const LangOptions &LangOpts = PP.getLangOptions();
// Because we inherit the feature list from HasFeature, this string switch
// must be less restrictive than HasFeature's.
return llvm::StringSwitch<bool>(II->getName())
// C11 features supported by other languages as extensions.
.Case("c_alignas", true)
.Case("c_atomic", true)
.Case("c_generic_selections", true)
.Case("c_static_assert", true)
// C++0x features supported by other languages as extensions.
.Case("cxx_atomic", LangOpts.CPlusPlus)
.Case("cxx_deleted_functions", LangOpts.CPlusPlus)
.Case("cxx_explicit_conversions", LangOpts.CPlusPlus)
.Case("cxx_inline_namespaces", LangOpts.CPlusPlus)
.Case("cxx_nonstatic_member_init", LangOpts.CPlusPlus)
.Case("cxx_override_control", LangOpts.CPlusPlus)
.Case("cxx_range_for", LangOpts.CPlusPlus)
.Case("cxx_reference_qualified_functions", LangOpts.CPlusPlus)
.Case("cxx_rvalue_references", LangOpts.CPlusPlus)
/// HasAttribute - Return true if we recognize and implement the attribute
/// specified by the given identifier.
static bool HasAttribute(const IdentifierInfo *II) {
return llvm::StringSwitch<bool>(II->getName())
#include "clang/Lex/"
/// EvaluateHasIncludeCommon - Process a '__has_include("path")'
/// or '__has_include_next("path")' expression.
/// Returns true if successful.
static bool EvaluateHasIncludeCommon(Token &Tok,
IdentifierInfo *II, Preprocessor &PP,
const DirectoryLookup *LookupFrom) {
SourceLocation LParenLoc;
// Get '('.
// Ensure we have a '('.
if (Tok.isNot(tok::l_paren)) {
PP.Diag(Tok.getLocation(), diag::err_pp_missing_lparen) << II->getName();
return false;
// Save '(' location for possible missing ')' message.
LParenLoc = Tok.getLocation();
// Get the file name.
// Reserve a buffer to get the spelling.
llvm::SmallString<128> FilenameBuffer;
StringRef Filename;
SourceLocation EndLoc;
switch (Tok.getKind()) {
case tok::eod:
// If the token kind is EOD, the error has already been diagnosed.
return false;
case tok::angle_string_literal:
case tok::string_literal: {
bool Invalid = false;
Filename = PP.getSpelling(Tok, FilenameBuffer, &Invalid);
if (Invalid)
return false;
case tok::less:
// This could be a <foo/bar.h> file coming from a macro expansion. In this
// case, glue the tokens together into FilenameBuffer and interpret those.
if (PP.ConcatenateIncludeName(FilenameBuffer, EndLoc))
return false; // Found <eod> but no ">"? Diagnostic already emitted.
Filename = FilenameBuffer.str();
PP.Diag(Tok.getLocation(), diag::err_pp_expects_filename);
return false;
bool isAngled = PP.GetIncludeFilenameSpelling(Tok.getLocation(), Filename);
// If GetIncludeFilenameSpelling set the start ptr to null, there was an
// error.
if (Filename.empty())
return false;
// Search include directories.
const DirectoryLookup *CurDir;
const FileEntry *File =
PP.LookupFile(Filename, isAngled, LookupFrom, CurDir, NULL, NULL, NULL);
// Get the result value. Result = true means the file exists.
bool Result = File != 0;
// Get ')'.
// Ensure we have a trailing ).
if (Tok.isNot(tok::r_paren)) {
PP.Diag(Tok.getLocation(), diag::err_pp_missing_rparen) << II->getName();
PP.Diag(LParenLoc, diag::note_matching) << "(";
return false;
return Result;
/// EvaluateHasInclude - Process a '__has_include("path")' expression.
/// Returns true if successful.
static bool EvaluateHasInclude(Token &Tok, IdentifierInfo *II,
Preprocessor &PP) {
return EvaluateHasIncludeCommon(Tok, II, PP, NULL);
/// EvaluateHasIncludeNext - Process '__has_include_next("path")' expression.
/// Returns true if successful.
static bool EvaluateHasIncludeNext(Token &Tok,
IdentifierInfo *II, Preprocessor &PP) {
// __has_include_next is like __has_include, except that we start
// searching after the current found directory. If we can't do this,
// issue a diagnostic.
const DirectoryLookup *Lookup = PP.GetCurDirLookup();
if (PP.isInPrimaryFile()) {
Lookup = 0;
PP.Diag(Tok, diag::pp_include_next_in_primary);
} else if (Lookup == 0) {
PP.Diag(Tok, diag::pp_include_next_absolute_path);
} else {
// Start looking up in the next directory.
return EvaluateHasIncludeCommon(Tok, II, PP, Lookup);
/// ExpandBuiltinMacro - If an identifier token is read that is to be expanded
/// as a builtin macro, handle it and return the next token as 'Tok'.
void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
// Figure out which token this is.
IdentifierInfo *II = Tok.getIdentifierInfo();
assert(II && "Can't be a macro without id info!");
// If this is an _Pragma or Microsoft __pragma directive, expand it,
// invoke the pragma handler, then lex the token after it.
if (II == Ident_Pragma)
return Handle_Pragma(Tok);
else if (II == Ident__pragma) // in non-MS mode this is null
return HandleMicrosoft__pragma(Tok);
llvm::SmallString<128> TmpBuffer;
llvm::raw_svector_ostream OS(TmpBuffer);
// Set up the return result.
if (II == Ident__LINE__) {
// C99 6.10.8: "__LINE__: The presumed line number (within the current
// source file) of the current source line (an integer constant)". This can
// be affected by #line.
SourceLocation Loc = Tok.getLocation();
// Advance to the location of the first _, this might not be the first byte
// of the token if it starts with an escaped newline.
Loc = AdvanceToTokenCharacter(Loc, 0);
// One wrinkle here is that GCC expands __LINE__ to location of the *end* of
// a macro expansion. This doesn't matter for object-like macros, but
// can matter for a function-like macro that expands to contain __LINE__.
// Skip down through expansion points until we find a file loc for the
// end of the expansion history.
Loc = SourceMgr.getExpansionRange(Loc).second;
PresumedLoc PLoc = SourceMgr.getPresumedLoc(Loc);
// __LINE__ expands to a simple numeric value.
OS << (PLoc.isValid()? PLoc.getLine() : 1);
} else if (II == Ident__FILE__ || II == Ident__BASE_FILE__) {
// C99 6.10.8: "__FILE__: The presumed name of the current source file (a
// character string literal)". This can be affected by #line.
PresumedLoc PLoc = SourceMgr.getPresumedLoc(Tok.getLocation());
// __BASE_FILE__ is a GNU extension that returns the top of the presumed
// #include stack instead of the current file.
if (II == Ident__BASE_FILE__ && PLoc.isValid()) {
SourceLocation NextLoc = PLoc.getIncludeLoc();
while (NextLoc.isValid()) {
PLoc = SourceMgr.getPresumedLoc(NextLoc);
if (PLoc.isInvalid())
NextLoc = PLoc.getIncludeLoc();
// Escape this filename. Turn '\' -> '\\' '"' -> '\"'
llvm::SmallString<128> FN;
if (PLoc.isValid()) {
FN += PLoc.getFilename();
OS << '"' << FN.str() << '"';
} else if (II == Ident__DATE__) {
if (!DATELoc.isValid())
ComputeDATE_TIME(DATELoc, TIMELoc, *this);
Tok.setLength(strlen("\"Mmm dd yyyy\""));
Tok.setLocation(SourceMgr.createExpansionLoc(DATELoc, Tok.getLocation(),
} else if (II == Ident__TIME__) {
if (!TIMELoc.isValid())
ComputeDATE_TIME(DATELoc, TIMELoc, *this);
Tok.setLocation(SourceMgr.createExpansionLoc(TIMELoc, Tok.getLocation(),
} else if (II == Ident__INCLUDE_LEVEL__) {
// Compute the presumed include depth of this token. This can be affected
// by GNU line markers.
unsigned Depth = 0;
PresumedLoc PLoc = SourceMgr.getPresumedLoc(Tok.getLocation());
if (PLoc.isValid()) {
PLoc = SourceMgr.getPresumedLoc(PLoc.getIncludeLoc());
for (; PLoc.isValid(); ++Depth)
PLoc = SourceMgr.getPresumedLoc(PLoc.getIncludeLoc());
// __INCLUDE_LEVEL__ expands to a simple numeric value.
OS << Depth;
} else if (II == Ident__TIMESTAMP__) {
// MSVC, ICC, GCC, VisualAge C++ extension. The generated string should be
// of the form "Ddd Mmm dd hh::mm::ss yyyy", which is returned by asctime.
// Get the file that we are lexing out of. If we're currently lexing from
// a macro, dig into the include stack.
const FileEntry *CurFile = 0;
PreprocessorLexer *TheLexer = getCurrentFileLexer();
if (TheLexer)
CurFile = SourceMgr.getFileEntryForID(TheLexer->getFileID());
const char *Result;
if (CurFile) {
time_t TT = CurFile->getModificationTime();
struct tm *TM = localtime(&TT);
Result = asctime(TM);
} else {
Result = "??? ??? ?? ??:??:?? ????\n";
// Surround the string with " and strip the trailing newline.
OS << '"' << StringRef(Result, strlen(Result)-1) << '"';
} else if (II == Ident__COUNTER__) {
// __COUNTER__ expands to a simple numeric value.
OS << CounterValue++;
} else if (II == Ident__has_feature ||
II == Ident__has_extension ||
II == Ident__has_builtin ||
II == Ident__has_attribute) {
// The argument to these builtins should be a parenthesized identifier.
SourceLocation StartLoc = Tok.getLocation();
bool IsValid = false;
IdentifierInfo *FeatureII = 0;
// Read the '('.
if ( {
// Read the identifier
if ( {
FeatureII = Tok.getIdentifierInfo();
// Read the ')'.
if (
IsValid = true;
bool Value = false;
if (!IsValid)
Diag(StartLoc, diag::err_feature_check_malformed);
else if (II == Ident__has_builtin) {
// Check for a builtin is trivial.
Value = FeatureII->getBuiltinID() != 0;
} else if (II == Ident__has_attribute)
Value = HasAttribute(FeatureII);
else if (II == Ident__has_extension)
Value = HasExtension(*this, FeatureII);
else {
assert(II == Ident__has_feature && "Must be feature check");
Value = HasFeature(*this, FeatureII);
OS << (int)Value;
} else if (II == Ident__has_include ||
II == Ident__has_include_next) {
// The argument to these two builtins should be a parenthesized
// file name string literal using angle brackets (<>) or
// double-quotes ("").
bool Value;
if (II == Ident__has_include)
Value = EvaluateHasInclude(Tok, II, *this);
Value = EvaluateHasIncludeNext(Tok, II, *this);
OS << (int)Value;
} else if (II == Ident__has_warning) {
// The argument should be a parenthesized string literal.
// The argument to these builtins should be a parenthesized identifier.
SourceLocation StartLoc = Tok.getLocation();
bool IsValid = false;
bool Value = false;
// Read the '('.
do {
if ( {
// Read the string.
// We need at least one string literal.
if (! {
StartLoc = Tok.getLocation();
IsValid = false;
// Eat tokens until ')'.
do Lex(Tok); while (!( ||;
// String concatenation allows multiple strings, which can even come
// from macro expansion.
SmallVector<Token, 4> StrToks;
while ( {
// Is the end a ')'?
if (!(IsValid =
// Concatenate and parse the strings.
StringLiteralParser Literal(&StrToks[0], StrToks.size(), *this);
assert(Literal.isAscii() && "Didn't allow wide strings in");
if (Literal.hadError)
if (Literal.Pascal) {
Diag(Tok, diag::warn_pragma_diagnostic_invalid);
StringRef WarningName(Literal.GetString());
if (WarningName.size() < 3 || WarningName[0] != '-' ||
WarningName[1] != 'W') {
Diag(StrToks[0].getLocation(), diag::warn_has_warning_invalid_option);
// Finally, check if the warning flags maps to a diagnostic group.
// We construct a SmallVector here to talk to getDiagnosticIDs().
// Although we don't use the result, this isn't a hot path, and not
// worth special casing.
llvm::SmallVector<diag::kind, 10> Diags;
Value = !getDiagnostics().getDiagnosticIDs()->
getDiagnosticsInGroup(WarningName.substr(2), Diags);
} while (false);
if (!IsValid)
Diag(StartLoc, diag::err_warning_check_malformed);
OS << (int)Value;
} else {
llvm_unreachable("Unknown identifier!");
CreateString(OS.str().data(), OS.str().size(), Tok,
Tok.getLocation(), Tok.getLocation());
void Preprocessor::markMacroAsUsed(MacroInfo *MI) {
// If the 'used' status changed, and the macro requires 'unused' warning,
// remove its SourceLocation from the warn-for-unused-macro locations.
if (MI->isWarnIfUnused() && !MI->isUsed())