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//===--- PPLexerChange.cpp - Handle changing lexers in the preprocessor ---===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// This file implements pieces of the Preprocessor interface that manage the
// current lexer stack.
#include "clang/Lex/Preprocessor.h"
#include "clang/Lex/PreprocessorOptions.h"
#include "clang/Basic/FileManager.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Lex/HeaderSearch.h"
#include "clang/Lex/LexDiagnostic.h"
#include "clang/Lex/MacroInfo.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Path.h"
using namespace clang;
PPCallbacks::~PPCallbacks() {}
// Miscellaneous Methods.
/// isInPrimaryFile - Return true if we're in the top-level file, not in a
/// \#include. This looks through macro expansions and active _Pragma lexers.
bool Preprocessor::isInPrimaryFile() const {
if (IsFileLexer())
return IncludeMacroStack.empty();
// If there are any stacked lexers, we're in a #include.
assert(IsFileLexer(IncludeMacroStack[0]) &&
"Top level include stack isn't our primary lexer?");
return std::none_of(
IncludeMacroStack.begin() + 1, IncludeMacroStack.end(),
[&](const IncludeStackInfo &ISI) -> bool { return IsFileLexer(ISI); });
/// getCurrentLexer - Return the current file lexer being lexed from. Note
/// that this ignores any potentially active macro expansions and _Pragma
/// expansions going on at the time.
PreprocessorLexer *Preprocessor::getCurrentFileLexer() const {
if (IsFileLexer())
return CurPPLexer;
// Look for a stacked lexer.
for (const IncludeStackInfo &ISI : llvm::reverse(IncludeMacroStack)) {
if (IsFileLexer(ISI))
return ISI.ThePPLexer;
return nullptr;
// Methods for Entering and Callbacks for leaving various contexts
/// EnterSourceFile - Add a source file to the top of the include stack and
/// start lexing tokens from it instead of the current buffer.
bool Preprocessor::EnterSourceFile(FileID FID, const DirectoryLookup *CurDir,
SourceLocation Loc) {
assert(!CurTokenLexer && "Cannot #include a file inside a macro!");
if (MaxIncludeStackDepth < IncludeMacroStack.size())
MaxIncludeStackDepth = IncludeMacroStack.size();
// Get the MemoryBuffer for this FID, if it fails, we fail.
bool Invalid = false;
const llvm::MemoryBuffer *InputFile =
getSourceManager().getBuffer(FID, Loc, &Invalid);
if (Invalid) {
SourceLocation FileStart = SourceMgr.getLocForStartOfFile(FID);
Diag(Loc, diag::err_pp_error_opening_file)
<< std::string(SourceMgr.getBufferName(FileStart)) << "";
return true;
if (isCodeCompletionEnabled() &&
SourceMgr.getFileEntryForID(FID) == CodeCompletionFile) {
CodeCompletionFileLoc = SourceMgr.getLocForStartOfFile(FID);
CodeCompletionLoc =
EnterSourceFileWithLexer(new Lexer(FID, InputFile, *this), CurDir);
return false;
/// EnterSourceFileWithLexer - Add a source file to the top of the include stack
/// and start lexing tokens from it instead of the current buffer.
void Preprocessor::EnterSourceFileWithLexer(Lexer *TheLexer,
const DirectoryLookup *CurDir) {
// Add the current lexer to the include stack.
if (CurPPLexer || CurTokenLexer)
CurPPLexer = TheLexer;
CurDirLookup = CurDir;
CurLexerSubmodule = nullptr;
if (CurLexerKind != CLK_LexAfterModuleImport)
CurLexerKind = CLK_Lexer;
// Notify the client, if desired, that we are in a new source file.
if (Callbacks && !CurLexer->Is_PragmaLexer) {
SrcMgr::CharacteristicKind FileType =
PPCallbacks::EnterFile, FileType);
/// EnterMacro - Add a Macro to the top of the include stack and start lexing
/// tokens from it instead of the current buffer.
void Preprocessor::EnterMacro(Token &Tok, SourceLocation ILEnd,
MacroInfo *Macro, MacroArgs *Args) {
std::unique_ptr<TokenLexer> TokLexer;
if (NumCachedTokenLexers == 0) {
TokLexer = std::make_unique<TokenLexer>(Tok, ILEnd, Macro, Args, *this);
} else {
TokLexer = std::move(TokenLexerCache[--NumCachedTokenLexers]);
TokLexer->Init(Tok, ILEnd, Macro, Args);
CurDirLookup = nullptr;
CurTokenLexer = std::move(TokLexer);
if (CurLexerKind != CLK_LexAfterModuleImport)
CurLexerKind = CLK_TokenLexer;
/// EnterTokenStream - Add a "macro" context to the top of the include stack,
/// which will cause the lexer to start returning the specified tokens.
/// If DisableMacroExpansion is true, tokens lexed from the token stream will
/// not be subject to further macro expansion. Otherwise, these tokens will
/// be re-macro-expanded when/if expansion is enabled.
/// If OwnsTokens is false, this method assumes that the specified stream of
/// tokens has a permanent owner somewhere, so they do not need to be copied.
/// If it is true, it assumes the array of tokens is allocated with new[] and
/// must be freed.
void Preprocessor::EnterTokenStream(const Token *Toks, unsigned NumToks,
bool DisableMacroExpansion, bool OwnsTokens,
bool IsReinject) {
if (CurLexerKind == CLK_CachingLexer) {
if (CachedLexPos < CachedTokens.size()) {
assert(IsReinject && "new tokens in the middle of cached stream");
// We're entering tokens into the middle of our cached token stream. We
// can't represent that, so just insert the tokens into the buffer.
CachedTokens.insert(CachedTokens.begin() + CachedLexPos,
Toks, Toks + NumToks);
if (OwnsTokens)
delete [] Toks;
// New tokens are at the end of the cached token sequnece; insert the
// token stream underneath the caching lexer.
EnterTokenStream(Toks, NumToks, DisableMacroExpansion, OwnsTokens,
// Create a macro expander to expand from the specified token stream.
std::unique_ptr<TokenLexer> TokLexer;
if (NumCachedTokenLexers == 0) {
TokLexer = std::make_unique<TokenLexer>(
Toks, NumToks, DisableMacroExpansion, OwnsTokens, IsReinject, *this);
} else {
TokLexer = std::move(TokenLexerCache[--NumCachedTokenLexers]);
TokLexer->Init(Toks, NumToks, DisableMacroExpansion, OwnsTokens,
// Save our current state.
CurDirLookup = nullptr;
CurTokenLexer = std::move(TokLexer);
if (CurLexerKind != CLK_LexAfterModuleImport)
CurLexerKind = CLK_TokenLexer;
/// Compute the relative path that names the given file relative to
/// the given directory.
static void computeRelativePath(FileManager &FM, const DirectoryEntry *Dir,
const FileEntry *File,
SmallString<128> &Result) {
StringRef FilePath = File->getDir()->getName();
StringRef Path = FilePath;
while (!Path.empty()) {
if (auto CurDir = FM.getDirectory(Path)) {
if (*CurDir == Dir) {
Result = FilePath.substr(Path.size());
Path = llvm::sys::path::parent_path(Path);
Result = File->getName();
void Preprocessor::PropagateLineStartLeadingSpaceInfo(Token &Result) {
if (CurTokenLexer) {
if (CurLexer) {
// FIXME: Handle other kinds of lexers? It generally shouldn't matter,
// but it might if they're empty?
/// Determine the location to use as the end of the buffer for a lexer.
/// If the file ends with a newline, form the EOF token on the newline itself,
/// rather than "on the line following it", which doesn't exist. This makes
/// diagnostics relating to the end of file include the last file that the user
/// actually typed, which is goodness.
const char *Preprocessor::getCurLexerEndPos() {
const char *EndPos = CurLexer->BufferEnd;
if (EndPos != CurLexer->BufferStart &&
(EndPos[-1] == '\n' || EndPos[-1] == '\r')) {
// Handle \n\r and \r\n:
if (EndPos != CurLexer->BufferStart &&
(EndPos[-1] == '\n' || EndPos[-1] == '\r') &&
EndPos[-1] != EndPos[0])
return EndPos;
static void collectAllSubModulesWithUmbrellaHeader(
const Module &Mod, SmallVectorImpl<const Module *> &SubMods) {
if (Mod.getUmbrellaHeader())
for (auto *M : Mod.submodules())
collectAllSubModulesWithUmbrellaHeader(*M, SubMods);
void Preprocessor::diagnoseMissingHeaderInUmbrellaDir(const Module &Mod) {
assert(Mod.getUmbrellaHeader() && "Module must use umbrella header");
SourceLocation StartLoc =
if (getDiagnostics().isIgnored(diag::warn_uncovered_module_header, StartLoc))
ModuleMap &ModMap = getHeaderSearchInfo().getModuleMap();
const DirectoryEntry *Dir = Mod.getUmbrellaDir().Entry;
llvm::vfs::FileSystem &FS = FileMgr.getVirtualFileSystem();
std::error_code EC;
for (llvm::vfs::recursive_directory_iterator Entry(FS, Dir->getName(), EC),
Entry != End && !EC; Entry.increment(EC)) {
using llvm::StringSwitch;
// Check whether this entry has an extension typically associated with
// headers.
if (!StringSwitch<bool>(llvm::sys::path::extension(Entry->path()))
.Cases(".h", ".H", ".hh", ".hpp", true)
if (auto Header = getFileManager().getFile(Entry->path()))
if (!getSourceManager().hasFileInfo(*Header)) {
if (!ModMap.isHeaderInUnavailableModule(*Header)) {
// Find the relative path that would access this header.
SmallString<128> RelativePath;
computeRelativePath(FileMgr, Dir, *Header, RelativePath);
Diag(StartLoc, diag::warn_uncovered_module_header)
<< Mod.getFullModuleName() << RelativePath;
/// HandleEndOfFile - This callback is invoked when the lexer hits the end of
/// the current file. This either returns the EOF token or pops a level off
/// the include stack and keeps going.
bool Preprocessor::HandleEndOfFile(Token &Result, bool isEndOfMacro) {
assert(!CurTokenLexer &&
"Ending a file when currently in a macro!");
// If we have an unclosed module region from a pragma at the end of a
// module, complain and close it now.
const bool LeavingSubmodule = CurLexer && CurLexerSubmodule;
if ((LeavingSubmodule || IncludeMacroStack.empty()) &&
!BuildingSubmoduleStack.empty() &&
BuildingSubmoduleStack.back().IsPragma) {
Module *M = LeaveSubmodule(/*ForPragma*/true);
const char *EndPos = getCurLexerEndPos();
CurLexer->BufferPtr = EndPos;
CurLexer->FormTokenWithChars(Result, EndPos, tok::annot_module_end);
return true;
// See if this file had a controlling macro.
if (CurPPLexer) { // Not ending a macro, ignore it.
if (const IdentifierInfo *ControllingMacro =
CurPPLexer->MIOpt.GetControllingMacroAtEndOfFile()) {
// Okay, this has a controlling macro, remember in HeaderFileInfo.
if (const FileEntry *FE = CurPPLexer->getFileEntry()) {
HeaderInfo.SetFileControllingMacro(FE, ControllingMacro);
if (MacroInfo *MI =
if (const IdentifierInfo *DefinedMacro =
CurPPLexer->MIOpt.GetDefinedMacro()) {
if (!isMacroDefined(ControllingMacro) &&
DefinedMacro != ControllingMacro &&
HeaderInfo.FirstTimeLexingFile(FE)) {
// If the edit distance between the two macros is more than 50%,
// DefinedMacro may not be header guard, or can be header guard of
// another header file. Therefore, it maybe defining something
// completely different. This can be observed in the wild when
// handling feature macros or header guards in different files.
const StringRef ControllingMacroName = ControllingMacro->getName();
const StringRef DefinedMacroName = DefinedMacro->getName();
const size_t MaxHalfLength = std::max(ControllingMacroName.size(),
DefinedMacroName.size()) / 2;
const unsigned ED = ControllingMacroName.edit_distance(
DefinedMacroName, true, MaxHalfLength);
if (ED <= MaxHalfLength) {
// Emit a warning for a bad header guard.
<< CurPPLexer->MIOpt.GetMacroLocation() << ControllingMacro;
<< CurPPLexer->MIOpt.GetDefinedLocation() << DefinedMacro
<< ControllingMacro
<< FixItHint::CreateReplacement(
// Complain about reaching a true EOF within arc_cf_code_audited.
// We don't want to complain about reaching the end of a macro
// instantiation or a _Pragma.
if (PragmaARCCFCodeAuditedInfo.second.isValid() && !isEndOfMacro &&
!(CurLexer && CurLexer->Is_PragmaLexer)) {
// Recover by leaving immediately.
PragmaARCCFCodeAuditedInfo = {nullptr, SourceLocation()};
// Complain about reaching a true EOF within assume_nonnull.
// We don't want to complain about reaching the end of a macro
// instantiation or a _Pragma.
if (PragmaAssumeNonNullLoc.isValid() &&
!isEndOfMacro && !(CurLexer && CurLexer->Is_PragmaLexer)) {
Diag(PragmaAssumeNonNullLoc, diag::err_pp_eof_in_assume_nonnull);
// Recover by leaving immediately.
PragmaAssumeNonNullLoc = SourceLocation();
bool LeavingPCHThroughHeader = false;
// If this is a #include'd file, pop it off the include stack and continue
// lexing the #includer file.
if (!IncludeMacroStack.empty()) {
// If we lexed the code-completion file, act as if we reached EOF.
if (isCodeCompletionEnabled() && CurPPLexer &&
SourceMgr.getLocForStartOfFile(CurPPLexer->getFileID()) ==
CodeCompletionFileLoc) {
assert(CurLexer && "Got EOF but no current lexer set!");
CurLexer->FormTokenWithChars(Result, CurLexer->BufferEnd, tok::eof);
CurPPLexer = nullptr;
return true;
if (!isEndOfMacro && CurPPLexer &&
SourceMgr.getIncludeLoc(CurPPLexer->getFileID()).isValid()) {
// Notify SourceManager to record the number of FileIDs that were created
// during lexing of the #include'd file.
unsigned NumFIDs =
SourceMgr.local_sloc_entry_size() -
CurPPLexer->getInitialNumSLocEntries() + 1/*#include'd file*/;
SourceMgr.setNumCreatedFIDsForFileID(CurPPLexer->getFileID(), NumFIDs);
bool ExitedFromPredefinesFile = false;
FileID ExitedFID;
if (!isEndOfMacro && CurPPLexer) {
ExitedFID = CurPPLexer->getFileID();
assert(PredefinesFileID.isValid() &&
"HandleEndOfFile is called before PredefinesFileId is set");
ExitedFromPredefinesFile = (PredefinesFileID == ExitedFID);
if (LeavingSubmodule) {
// We're done with this submodule.
Module *M = LeaveSubmodule(/*ForPragma*/false);
// Notify the parser that we've left the module.
const char *EndPos = getCurLexerEndPos();
CurLexer->BufferPtr = EndPos;
CurLexer->FormTokenWithChars(Result, EndPos, tok::annot_module_end);
bool FoundPCHThroughHeader = false;
if (CurPPLexer && creatingPCHWithThroughHeader() &&
FoundPCHThroughHeader = true;
// We're done with the #included file.
// Propagate info about start-of-line/leading white-space/etc.
// Notify the client, if desired, that we are in a new source file.
if (Callbacks && !isEndOfMacro && CurPPLexer) {
SrcMgr::CharacteristicKind FileType =
PPCallbacks::ExitFile, FileType, ExitedFID);
// Restore conditional stack from the preamble right after exiting from the
// predefines file.
if (ExitedFromPredefinesFile)
if (!isEndOfMacro && CurPPLexer && FoundPCHThroughHeader &&
(isInPrimaryFile() ||
CurPPLexer->getFileID() == getPredefinesFileID())) {
// Leaving the through header. Continue directly to end of main file
// processing.
LeavingPCHThroughHeader = true;
} else {
// Client should lex another token unless we generated an EOM.
return LeavingSubmodule;
// If this is the end of the main file, form an EOF token.
assert(CurLexer && "Got EOF but no current lexer set!");
const char *EndPos = getCurLexerEndPos();
CurLexer->BufferPtr = EndPos;
CurLexer->FormTokenWithChars(Result, EndPos, tok::eof);
if (isCodeCompletionEnabled()) {
// Inserting the code-completion point increases the source buffer by 1,
// but the main FileID was created before inserting the point.
// Compensate by reducing the EOF location by 1, otherwise the location
// will point to the next FileID.
// FIXME: This is hacky, the code-completion point should probably be
// inserted before the main FileID is created.
if (CurLexer->getFileLoc() == CodeCompletionFileLoc)
if (creatingPCHWithThroughHeader() && !LeavingPCHThroughHeader) {
// Reached the end of the compilation without finding the through header.
Diag(CurLexer->getFileLoc(), diag::err_pp_through_header_not_seen)
<< PPOpts->PCHThroughHeader << 0;
if (!isIncrementalProcessingEnabled())
// We're done with lexing.
if (!isIncrementalProcessingEnabled())
CurPPLexer = nullptr;
if (TUKind == TU_Complete) {
// This is the end of the top-level file. 'WarnUnusedMacroLocs' has
// collected all macro locations that we need to warn because they are not
// used.
for (WarnUnusedMacroLocsTy::iterator
I=WarnUnusedMacroLocs.begin(), E=WarnUnusedMacroLocs.end();
I!=E; ++I)
Diag(*I, diag::pp_macro_not_used);
// If we are building a module that has an umbrella header, make sure that
// each of the headers within the directory, including all submodules, is
// covered by the umbrella header was actually included by the umbrella
// header.
if (Module *Mod = getCurrentModule()) {
llvm::SmallVector<const Module *, 4> AllMods;
collectAllSubModulesWithUmbrellaHeader(*Mod, AllMods);
for (auto *M : AllMods)
return true;
/// HandleEndOfTokenLexer - This callback is invoked when the current TokenLexer
/// hits the end of its token stream.
bool Preprocessor::HandleEndOfTokenLexer(Token &Result) {
assert(CurTokenLexer && !CurPPLexer &&
"Ending a macro when currently in a #include file!");
if (!MacroExpandingLexersStack.empty() &&
MacroExpandingLexersStack.back().first == CurTokenLexer.get())
// Delete or cache the now-dead macro expander.
if (NumCachedTokenLexers == TokenLexerCacheSize)
TokenLexerCache[NumCachedTokenLexers++] = std::move(CurTokenLexer);
// Handle this like a #include file being popped off the stack.
return HandleEndOfFile(Result, true);
/// RemoveTopOfLexerStack - Pop the current lexer/macro exp off the top of the
/// lexer stack. This should only be used in situations where the current
/// state of the top-of-stack lexer is unknown.
void Preprocessor::RemoveTopOfLexerStack() {
assert(!IncludeMacroStack.empty() && "Ran out of stack entries to load");
if (CurTokenLexer) {
// Delete or cache the now-dead macro expander.
if (NumCachedTokenLexers == TokenLexerCacheSize)
TokenLexerCache[NumCachedTokenLexers++] = std::move(CurTokenLexer);
/// HandleMicrosoftCommentPaste - When the macro expander pastes together a
/// comment (/##/) in microsoft mode, this method handles updating the current
/// state, returning the token on the next source line.
void Preprocessor::HandleMicrosoftCommentPaste(Token &Tok) {
assert(CurTokenLexer && !CurPPLexer &&
"Pasted comment can only be formed from macro");
// We handle this by scanning for the closest real lexer, switching it to
// raw mode and preprocessor mode. This will cause it to return \n as an
// explicit EOD token.
PreprocessorLexer *FoundLexer = nullptr;
bool LexerWasInPPMode = false;
for (const IncludeStackInfo &ISI : llvm::reverse(IncludeMacroStack)) {
if (ISI.ThePPLexer == nullptr) continue; // Scan for a real lexer.
// Once we find a real lexer, mark it as raw mode (disabling macro
// expansions) and preprocessor mode (return EOD). We know that the lexer
// was *not* in raw mode before, because the macro that the comment came
// from was expanded. However, it could have already been in preprocessor
// mode (#if COMMENT) in which case we have to return it to that mode and
// return EOD.
FoundLexer = ISI.ThePPLexer;
FoundLexer->LexingRawMode = true;
LexerWasInPPMode = FoundLexer->ParsingPreprocessorDirective;
FoundLexer->ParsingPreprocessorDirective = true;
// Okay, we either found and switched over the lexer, or we didn't find a
// lexer. In either case, finish off the macro the comment came from, getting
// the next token.
if (!HandleEndOfTokenLexer(Tok)) Lex(Tok);
// Discarding comments as long as we don't have EOF or EOD. This 'comments
// out' the rest of the line, including any tokens that came from other macros
// that were active, as in:
// #define submacro a COMMENT b
// submacro c
// which should lex to 'a' only: 'b' and 'c' should be removed.
while (Tok.isNot(tok::eod) && Tok.isNot(tok::eof))
// If we got an eod token, then we successfully found the end of the line.
if ( {
assert(FoundLexer && "Can't get end of line without an active lexer");
// Restore the lexer back to normal mode instead of raw mode.
FoundLexer->LexingRawMode = false;
// If the lexer was already in preprocessor mode, just return the EOD token
// to finish the preprocessor line.
if (LexerWasInPPMode) return;
// Otherwise, switch out of PP mode and return the next lexed token.
FoundLexer->ParsingPreprocessorDirective = false;
return Lex(Tok);
// If we got an EOF token, then we reached the end of the token stream but
// didn't find an explicit \n. This can only happen if there was no lexer
// active (an active lexer would return EOD at EOF if there was no \n in
// preprocessor directive mode), so just return EOF as our token.
assert(!FoundLexer && "Lexer should return EOD before EOF in PP mode");
void Preprocessor::EnterSubmodule(Module *M, SourceLocation ImportLoc,
bool ForPragma) {
if (!getLangOpts().ModulesLocalVisibility) {
// Just track that we entered this submodule.
BuildingSubmoduleInfo(M, ImportLoc, ForPragma, CurSubmoduleState,
if (Callbacks)
Callbacks->EnteredSubmodule(M, ImportLoc, ForPragma);
// Resolve as much of the module definition as we can now, before we enter
// one of its headers.
// FIXME: Can we enable Complain here?
// FIXME: Can we do this when local visibility is disabled?
ModuleMap &ModMap = getHeaderSearchInfo().getModuleMap();
ModMap.resolveExports(M, /*Complain=*/false);
ModMap.resolveUses(M, /*Complain=*/false);
ModMap.resolveConflicts(M, /*Complain=*/false);
// If this is the first time we've entered this module, set up its state.
auto R = Submodules.insert(std::make_pair(M, SubmoduleState()));
auto &State = R.first->second;
bool FirstTime = R.second;
if (FirstTime) {
// Determine the set of starting macros for this submodule; take these
// from the "null" module (the predefines buffer).
// FIXME: If we have local visibility but not modules enabled, the
// NullSubmoduleState is polluted by #defines in the top-level source
// file.
auto &StartingMacros = NullSubmoduleState.Macros;
// Restore to the starting state.
// FIXME: Do this lazily, when each macro name is first referenced.
for (auto &Macro : StartingMacros) {
// Skip uninteresting macros.
if (!Macro.second.getLatest() &&
MacroState MS(Macro.second.getLatest());
MS.setOverriddenMacros(*this, Macro.second.getOverriddenMacros());
State.Macros.insert(std::make_pair(Macro.first, std::move(MS)));
// Track that we entered this module.
BuildingSubmoduleInfo(M, ImportLoc, ForPragma, CurSubmoduleState,
if (Callbacks)
Callbacks->EnteredSubmodule(M, ImportLoc, ForPragma);
// Switch to this submodule as the current submodule.
CurSubmoduleState = &State;
// This module is visible to itself.
if (FirstTime)
makeModuleVisible(M, ImportLoc);
bool Preprocessor::needModuleMacros() const {
// If we're not within a submodule, we never need to create ModuleMacros.
if (BuildingSubmoduleStack.empty())
return false;
// If we are tracking module macro visibility even for textually-included
// headers, we need ModuleMacros.
if (getLangOpts().ModulesLocalVisibility)
return true;
// Otherwise, we only need module macros if we're actually compiling a module
// interface.
return getLangOpts().isCompilingModule();
Module *Preprocessor::LeaveSubmodule(bool ForPragma) {
if (BuildingSubmoduleStack.empty() ||
BuildingSubmoduleStack.back().IsPragma != ForPragma) {
assert(ForPragma && "non-pragma module enter/leave mismatch");
return nullptr;
auto &Info = BuildingSubmoduleStack.back();
Module *LeavingMod = Info.M;
SourceLocation ImportLoc = Info.ImportLoc;
if (!needModuleMacros() ||
(!getLangOpts().ModulesLocalVisibility &&
LeavingMod->getTopLevelModuleName() != getLangOpts().CurrentModule)) {
// If we don't need module macros, or this is not a module for which we
// are tracking macro visibility, don't build any, and preserve the list
// of pending names for the surrounding submodule.
if (Callbacks)
Callbacks->LeftSubmodule(LeavingMod, ImportLoc, ForPragma);
makeModuleVisible(LeavingMod, ImportLoc);
return LeavingMod;
// Create ModuleMacros for any macros defined in this submodule.
llvm::SmallPtrSet<const IdentifierInfo*, 8> VisitedMacros;
for (unsigned I = Info.OuterPendingModuleMacroNames;
I != PendingModuleMacroNames.size(); ++I) {
auto *II = const_cast<IdentifierInfo*>(PendingModuleMacroNames[I]);
if (!VisitedMacros.insert(II).second)
auto MacroIt = CurSubmoduleState->Macros.find(II);
if (MacroIt == CurSubmoduleState->Macros.end())
auto &Macro = MacroIt->second;
// Find the starting point for the MacroDirective chain in this submodule.
MacroDirective *OldMD = nullptr;
auto *OldState = Info.OuterSubmoduleState;
if (getLangOpts().ModulesLocalVisibility)
OldState = &NullSubmoduleState;
if (OldState && OldState != CurSubmoduleState) {
// FIXME: It'd be better to start at the state from when we most recently
// entered this submodule, but it doesn't really matter.
auto &OldMacros = OldState->Macros;
auto OldMacroIt = OldMacros.find(II);
if (OldMacroIt == OldMacros.end())
OldMD = nullptr;
OldMD = OldMacroIt->second.getLatest();
// This module may have exported a new macro. If so, create a ModuleMacro
// representing that fact.
bool ExplicitlyPublic = false;
for (auto *MD = Macro.getLatest(); MD != OldMD; MD = MD->getPrevious()) {
assert(MD && "broken macro directive chain");
if (auto *VisMD = dyn_cast<VisibilityMacroDirective>(MD)) {
// The latest visibility directive for a name in a submodule affects
// all the directives that come before it.
if (VisMD->isPublic())
ExplicitlyPublic = true;
else if (!ExplicitlyPublic)
// Private with no following public directive: not exported.
} else {
MacroInfo *Def = nullptr;
if (DefMacroDirective *DefMD = dyn_cast<DefMacroDirective>(MD))
Def = DefMD->getInfo();
// FIXME: Issue a warning if multiple headers for the same submodule
// define a macro, rather than silently ignoring all but the first.
bool IsNew;
// Don't bother creating a module macro if it would represent a #undef
// that doesn't override anything.
if (Def || !Macro.getOverriddenMacros().empty())
addModuleMacro(LeavingMod, II, Def,
Macro.getOverriddenMacros(), IsNew);
if (!getLangOpts().ModulesLocalVisibility) {
// This macro is exposed to the rest of this compilation as a
// ModuleMacro; we don't need to track its MacroDirective any more.
Macro.setOverriddenMacros(*this, {});
// FIXME: Before we leave this submodule, we should parse all the other
// headers within it. Otherwise, we're left with an inconsistent state
// where we've made the module visible but don't yet have its complete
// contents.
// Put back the outer module's state, if we're tracking it.
if (getLangOpts().ModulesLocalVisibility)
CurSubmoduleState = Info.OuterSubmoduleState;
if (Callbacks)
Callbacks->LeftSubmodule(LeavingMod, ImportLoc, ForPragma);
// A nested #include makes the included submodule visible.
makeModuleVisible(LeavingMod, ImportLoc);
return LeavingMod;