llvm-project/clang/lib/Lex/Pragma.cpp

430 lines
15 KiB
C++

//===--- Pragma.cpp - Pragma registration and handling --------------------===//
//
// 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 PragmaHandler/PragmaTable interfaces and implements
// pragma related methods of the Preprocessor class.
//
//===----------------------------------------------------------------------===//
#include "clang/Lex/Pragma.h"
#include "clang/Lex/HeaderSearch.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/FileManager.h"
#include "clang/Basic/SourceManager.h"
using namespace clang;
// Out-of-line destructor to provide a home for the class.
PragmaHandler::~PragmaHandler() {
}
//===----------------------------------------------------------------------===//
// PragmaNamespace Implementation.
//===----------------------------------------------------------------------===//
PragmaNamespace::~PragmaNamespace() {
for (unsigned i = 0, e = Handlers.size(); i != e; ++i)
delete Handlers[i];
}
/// FindHandler - Check to see if there is already a handler for the
/// specified name. If not, return the handler for the null identifier if it
/// exists, otherwise return null. If IgnoreNull is true (the default) then
/// the null handler isn't returned on failure to match.
PragmaHandler *PragmaNamespace::FindHandler(const IdentifierInfo *Name,
bool IgnoreNull) const {
PragmaHandler *NullHandler = 0;
for (unsigned i = 0, e = Handlers.size(); i != e; ++i) {
if (Handlers[i]->getName() == Name)
return Handlers[i];
if (Handlers[i]->getName() == 0)
NullHandler = Handlers[i];
}
return IgnoreNull ? 0 : NullHandler;
}
void PragmaNamespace::RemovePragmaHandler(PragmaHandler *Handler) {
for (unsigned i = 0, e = Handlers.size(); i != e; ++i) {
if (Handlers[i] == Handler) {
Handlers[i] = Handlers.back();
Handlers.pop_back();
return;
}
}
assert(0 && "Handler not registered in this namespace");
}
void PragmaNamespace::HandlePragma(Preprocessor &PP, Token &Tok) {
// Read the 'namespace' that the directive is in, e.g. STDC. Do not macro
// expand it, the user can have a STDC #define, that should not affect this.
PP.LexUnexpandedToken(Tok);
// Get the handler for this token. If there is no handler, ignore the pragma.
PragmaHandler *Handler = FindHandler(Tok.getIdentifierInfo(), false);
if (Handler == 0) return;
// Otherwise, pass it down.
Handler->HandlePragma(PP, Tok);
}
//===----------------------------------------------------------------------===//
// Preprocessor Pragma Directive Handling.
//===----------------------------------------------------------------------===//
/// HandlePragmaDirective - The "#pragma" directive has been parsed. Lex the
/// rest of the pragma, passing it to the registered pragma handlers.
void Preprocessor::HandlePragmaDirective() {
++NumPragma;
// Invoke the first level of pragma handlers which reads the namespace id.
Token Tok;
PragmaHandlers->HandlePragma(*this, Tok);
// If the pragma handler didn't read the rest of the line, consume it now.
if (CurPPLexer->ParsingPreprocessorDirective)
DiscardUntilEndOfDirective();
}
/// Handle_Pragma - Read a _Pragma directive, slice it up, process it, then
/// return the first token after the directive. The _Pragma token has just
/// been read into 'Tok'.
void Preprocessor::Handle_Pragma(Token &Tok) {
// Remember the pragma token location.
SourceLocation PragmaLoc = Tok.getLocation();
// Read the '('.
Lex(Tok);
if (Tok.isNot(tok::l_paren)) {
Diag(PragmaLoc, diag::err__Pragma_malformed);
return;
}
// Read the '"..."'.
Lex(Tok);
if (Tok.isNot(tok::string_literal) && Tok.isNot(tok::wide_string_literal)) {
Diag(PragmaLoc, diag::err__Pragma_malformed);
return;
}
// Remember the string.
std::string StrVal = getSpelling(Tok);
SourceLocation StrLoc = Tok.getLocation();
// Read the ')'.
Lex(Tok);
if (Tok.isNot(tok::r_paren)) {
Diag(PragmaLoc, diag::err__Pragma_malformed);
return;
}
// The _Pragma is lexically sound. Destringize according to C99 6.10.9.1.
if (StrVal[0] == 'L') // Remove L prefix.
StrVal.erase(StrVal.begin());
assert(StrVal[0] == '"' && StrVal[StrVal.size()-1] == '"' &&
"Invalid string token!");
// Remove the front quote, replacing it with a space, so that the pragma
// contents appear to have a space before them.
StrVal[0] = ' ';
// Replace the terminating quote with a \n\0.
StrVal[StrVal.size()-1] = '\n';
StrVal += '\0';
// Remove escaped quotes and escapes.
for (unsigned i = 0, e = StrVal.size(); i != e-1; ++i) {
if (StrVal[i] == '\\' &&
(StrVal[i+1] == '\\' || StrVal[i+1] == '"')) {
// \\ -> '\' and \" -> '"'.
StrVal.erase(StrVal.begin()+i);
--e;
}
}
// Plop the string (including the newline and trailing null) into a buffer
// where we can lex it.
SourceLocation TokLoc = CreateString(&StrVal[0], StrVal.size(), StrLoc);
const char *StrData = SourceMgr.getCharacterData(TokLoc);
// Make and enter a lexer object so that we lex and expand the tokens just
// like any others.
Lexer *TL = new Lexer(TokLoc, *this,
StrData, StrData+StrVal.size()-1 /* no null */);
// Ensure that the lexer thinks it is inside a directive, so that end \n will
// return an EOM token.
TL->ParsingPreprocessorDirective = true;
// This lexer really is for _Pragma.
TL->Is_PragmaLexer = true;
EnterSourceFileWithLexer(TL, 0);
// With everything set up, lex this as a #pragma directive.
HandlePragmaDirective();
// Finally, return whatever came after the pragma directive.
return Lex(Tok);
}
/// HandlePragmaOnce - Handle #pragma once. OnceTok is the 'once'.
///
void Preprocessor::HandlePragmaOnce(Token &OnceTok) {
if (isInPrimaryFile()) {
Diag(OnceTok, diag::pp_pragma_once_in_main_file);
return;
}
// Get the current file lexer we're looking at. Ignore _Pragma 'files' etc.
unsigned FileID = getCurrentFileLexer()->getFileID();
// Mark the file as a once-only file now.
HeaderInfo.MarkFileIncludeOnce(SourceMgr.getFileEntryForID(FileID));
}
void Preprocessor::HandlePragmaMark() {
assert(CurPPLexer && "No current lexer?");
if (CurLexer) CurLexer->ReadToEndOfLine();
else CurPTHLexer->DiscardToEndOfLine();
}
/// HandlePragmaPoison - Handle #pragma GCC poison. PoisonTok is the 'poison'.
///
void Preprocessor::HandlePragmaPoison(Token &PoisonTok) {
Token Tok;
while (1) {
// Read the next token to poison. While doing this, pretend that we are
// skipping while reading the identifier to poison.
// This avoids errors on code like:
// #pragma GCC poison X
// #pragma GCC poison X
if (CurPPLexer) CurPPLexer->LexingRawMode = true;
LexUnexpandedToken(Tok);
if (CurPPLexer) CurPPLexer->LexingRawMode = false;
// If we reached the end of line, we're done.
if (Tok.is(tok::eom)) return;
// Can only poison identifiers.
if (Tok.isNot(tok::identifier)) {
Diag(Tok, diag::err_pp_invalid_poison);
return;
}
// Look up the identifier info for the token. We disabled identifier lookup
// by saying we're skipping contents, so we need to do this manually.
IdentifierInfo *II = LookUpIdentifierInfo(Tok);
// Already poisoned.
if (II->isPoisoned()) continue;
// If this is a macro identifier, emit a warning.
if (II->hasMacroDefinition())
Diag(Tok, diag::pp_poisoning_existing_macro);
// Finally, poison it!
II->setIsPoisoned();
}
}
/// HandlePragmaSystemHeader - Implement #pragma GCC system_header. We know
/// that the whole directive has been parsed.
void Preprocessor::HandlePragmaSystemHeader(Token &SysHeaderTok) {
if (isInPrimaryFile()) {
Diag(SysHeaderTok, diag::pp_pragma_sysheader_in_main_file);
return;
}
// Get the current file lexer we're looking at. Ignore _Pragma 'files' etc.
PreprocessorLexer *TheLexer = getCurrentFileLexer();
// Mark the file as a system header.
const FileEntry *File = SourceMgr.getFileEntryForID(TheLexer->getFileID());
HeaderInfo.MarkFileSystemHeader(File);
// Notify the client, if desired, that we are in a new source file.
if (Callbacks)
Callbacks->FileChanged(SysHeaderTok.getLocation(),
PPCallbacks::SystemHeaderPragma, SrcMgr::C_System);
}
/// HandlePragmaDependency - Handle #pragma GCC dependency "foo" blah.
///
void Preprocessor::HandlePragmaDependency(Token &DependencyTok) {
Token FilenameTok;
CurPPLexer->LexIncludeFilename(FilenameTok);
// If the token kind is EOM, the error has already been diagnosed.
if (FilenameTok.is(tok::eom))
return;
// Reserve a buffer to get the spelling.
llvm::SmallVector<char, 128> FilenameBuffer;
FilenameBuffer.resize(FilenameTok.getLength());
const char *FilenameStart = &FilenameBuffer[0];
unsigned Len = getSpelling(FilenameTok, FilenameStart);
const char *FilenameEnd = FilenameStart+Len;
bool isAngled = GetIncludeFilenameSpelling(FilenameTok.getLocation(),
FilenameStart, FilenameEnd);
// If GetIncludeFilenameSpelling set the start ptr to null, there was an
// error.
if (FilenameStart == 0)
return;
// Search include directories for this file.
const DirectoryLookup *CurDir;
const FileEntry *File = LookupFile(FilenameStart, FilenameEnd,
isAngled, 0, CurDir);
if (File == 0) {
Diag(FilenameTok, diag::err_pp_file_not_found)
<< std::string(FilenameStart, FilenameEnd);
return;
}
unsigned FileID = getCurrentFileLexer()->getFileID();
const FileEntry *CurFile = SourceMgr.getFileEntryForID(FileID);
// If this file is older than the file it depends on, emit a diagnostic.
if (CurFile && CurFile->getModificationTime() < File->getModificationTime()) {
// Lex tokens at the end of the message and include them in the message.
std::string Message;
Lex(DependencyTok);
while (DependencyTok.isNot(tok::eom)) {
Message += getSpelling(DependencyTok) + " ";
Lex(DependencyTok);
}
Message.erase(Message.end()-1);
Diag(FilenameTok, diag::pp_out_of_date_dependency) << Message;
}
}
/// AddPragmaHandler - Add the specified pragma handler to the preprocessor.
/// If 'Namespace' is non-null, then it is a token required to exist on the
/// pragma line before the pragma string starts, e.g. "STDC" or "GCC".
void Preprocessor::AddPragmaHandler(const char *Namespace,
PragmaHandler *Handler) {
PragmaNamespace *InsertNS = PragmaHandlers;
// If this is specified to be in a namespace, step down into it.
if (Namespace) {
IdentifierInfo *NSID = getIdentifierInfo(Namespace);
// If there is already a pragma handler with the name of this namespace,
// we either have an error (directive with the same name as a namespace) or
// we already have the namespace to insert into.
if (PragmaHandler *Existing = PragmaHandlers->FindHandler(NSID)) {
InsertNS = Existing->getIfNamespace();
assert(InsertNS != 0 && "Cannot have a pragma namespace and pragma"
" handler with the same name!");
} else {
// Otherwise, this namespace doesn't exist yet, create and insert the
// handler for it.
InsertNS = new PragmaNamespace(NSID);
PragmaHandlers->AddPragma(InsertNS);
}
}
// Check to make sure we don't already have a pragma for this identifier.
assert(!InsertNS->FindHandler(Handler->getName()) &&
"Pragma handler already exists for this identifier!");
InsertNS->AddPragma(Handler);
}
/// RemovePragmaHandler - Remove the specific pragma handler from the
/// preprocessor. If \arg Namespace is non-null, then it should be the
/// namespace that \arg Handler was added to. It is an error to remove
/// a handler that has not been registered.
void Preprocessor::RemovePragmaHandler(const char *Namespace,
PragmaHandler *Handler) {
PragmaNamespace *NS = PragmaHandlers;
// If this is specified to be in a namespace, step down into it.
if (Namespace) {
IdentifierInfo *NSID = getIdentifierInfo(Namespace);
PragmaHandler *Existing = PragmaHandlers->FindHandler(NSID);
assert(Existing && "Namespace containing handler does not exist!");
NS = Existing->getIfNamespace();
assert(NS && "Invalid namespace, registered as a regular pragma handler!");
}
NS->RemovePragmaHandler(Handler);
// If this is a non-default namespace and it is now empty, remove
// it.
if (NS != PragmaHandlers && NS->IsEmpty())
PragmaHandlers->RemovePragmaHandler(NS);
}
namespace {
/// PragmaOnceHandler - "#pragma once" marks the file as atomically included.
struct PragmaOnceHandler : public PragmaHandler {
PragmaOnceHandler(const IdentifierInfo *OnceID) : PragmaHandler(OnceID) {}
virtual void HandlePragma(Preprocessor &PP, Token &OnceTok) {
PP.CheckEndOfDirective("#pragma once");
PP.HandlePragmaOnce(OnceTok);
}
};
/// PragmaMarkHandler - "#pragma mark ..." is ignored by the compiler, and the
/// rest of the line is not lexed.
struct PragmaMarkHandler : public PragmaHandler {
PragmaMarkHandler(const IdentifierInfo *MarkID) : PragmaHandler(MarkID) {}
virtual void HandlePragma(Preprocessor &PP, Token &MarkTok) {
PP.HandlePragmaMark();
}
};
/// PragmaPoisonHandler - "#pragma poison x" marks x as not usable.
struct PragmaPoisonHandler : public PragmaHandler {
PragmaPoisonHandler(const IdentifierInfo *ID) : PragmaHandler(ID) {}
virtual void HandlePragma(Preprocessor &PP, Token &PoisonTok) {
PP.HandlePragmaPoison(PoisonTok);
}
};
/// PragmaSystemHeaderHandler - "#pragma system_header" marks the current file
/// as a system header, which silences warnings in it.
struct PragmaSystemHeaderHandler : public PragmaHandler {
PragmaSystemHeaderHandler(const IdentifierInfo *ID) : PragmaHandler(ID) {}
virtual void HandlePragma(Preprocessor &PP, Token &SHToken) {
PP.HandlePragmaSystemHeader(SHToken);
PP.CheckEndOfDirective("#pragma");
}
};
struct PragmaDependencyHandler : public PragmaHandler {
PragmaDependencyHandler(const IdentifierInfo *ID) : PragmaHandler(ID) {}
virtual void HandlePragma(Preprocessor &PP, Token &DepToken) {
PP.HandlePragmaDependency(DepToken);
}
};
} // end anonymous namespace
/// RegisterBuiltinPragmas - Install the standard preprocessor pragmas:
/// #pragma GCC poison/system_header/dependency and #pragma once.
void Preprocessor::RegisterBuiltinPragmas() {
AddPragmaHandler(0, new PragmaOnceHandler(getIdentifierInfo("once")));
AddPragmaHandler(0, new PragmaMarkHandler(getIdentifierInfo("mark")));
AddPragmaHandler("GCC", new PragmaPoisonHandler(getIdentifierInfo("poison")));
AddPragmaHandler("GCC", new PragmaSystemHeaderHandler(
getIdentifierInfo("system_header")));
AddPragmaHandler("GCC", new PragmaDependencyHandler(
getIdentifierInfo("dependency")));
}