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//===--- DependencyFile.cpp - Generate dependency file --------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This code generates dependency files.
//
//===----------------------------------------------------------------------===//
#include "clang/Frontend/Utils.h"
#include "clang/Basic/FileManager.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Frontend/DependencyOutputOptions.h"
#include "clang/Frontend/FrontendDiagnostic.h"
#include "clang/Lex/DirectoryLookup.h"
#include "clang/Lex/ModuleMap.h"
#include "clang/Lex/PPCallbacks.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Serialization/ASTReader.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/raw_ostream.h"
using namespace clang;
namespace {
struct DepCollectorPPCallbacks : public PPCallbacks {
DependencyCollector &DepCollector;
SourceManager &SM;
DiagnosticsEngine &Diags;
DepCollectorPPCallbacks(DependencyCollector &L, SourceManager &SM,
DiagnosticsEngine &Diags)
: DepCollector(L), SM(SM), Diags(Diags) {}
void FileChanged(SourceLocation Loc, FileChangeReason Reason,
SrcMgr::CharacteristicKind FileType,
FileID PrevFID) override {
if (Reason != PPCallbacks::EnterFile)
return;
// Dependency generation really does want to go all the way to the
// file entry for a source location to find out what is depended on.
// We do not want #line markers to affect dependency generation!
if (Optional<StringRef> Filename = SM.getNonBuiltinFilenameForID(
SM.getFileID(SM.getExpansionLoc(Loc))))
DepCollector.maybeAddDependency(
llvm::sys::path::remove_leading_dotslash(*Filename),
/*FromModule*/ false, isSystem(FileType), /*IsModuleFile*/ false,
/*IsMissing*/ false);
}
void FileSkipped(const FileEntryRef &SkippedFile, const Token &FilenameTok,
SrcMgr::CharacteristicKind FileType) override {
StringRef Filename =
llvm::sys::path::remove_leading_dotslash(SkippedFile.getName());
DepCollector.maybeAddDependency(Filename, /*FromModule=*/false,
/*IsSystem=*/isSystem(FileType),
/*IsModuleFile=*/false,
/*IsMissing=*/false);
}
void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
StringRef FileName, bool IsAngled,
CharSourceRange FilenameRange,
Optional<FileEntryRef> File, StringRef SearchPath,
StringRef RelativePath, const Module *Imported,
SrcMgr::CharacteristicKind FileType) override {
if (!File)
DepCollector.maybeAddDependency(FileName, /*FromModule*/false,
/*IsSystem*/false, /*IsModuleFile*/false,
/*IsMissing*/true);
// Files that actually exist are handled by FileChanged.
}
void HasInclude(SourceLocation Loc, StringRef SpelledFilename, bool IsAngled,
Optional<FileEntryRef> File,
SrcMgr::CharacteristicKind FileType) override {
if (!File)
return;
StringRef Filename =
llvm::sys::path::remove_leading_dotslash(File->getName());
DepCollector.maybeAddDependency(Filename, /*FromModule=*/false,
/*IsSystem=*/isSystem(FileType),
/*IsModuleFile=*/false,
/*IsMissing=*/false);
}
void EndOfMainFile() override { DepCollector.finishedMainFile(Diags); }
};
struct DepCollectorMMCallbacks : public ModuleMapCallbacks {
DependencyCollector &DepCollector;
DepCollectorMMCallbacks(DependencyCollector &DC) : DepCollector(DC) {}
void moduleMapFileRead(SourceLocation Loc, const FileEntry &Entry,
bool IsSystem) override {
StringRef Filename = Entry.getName();
DepCollector.maybeAddDependency(Filename, /*FromModule*/false,
/*IsSystem*/IsSystem,
/*IsModuleFile*/false,
/*IsMissing*/false);
}
};
struct DepCollectorASTListener : public ASTReaderListener {
DependencyCollector &DepCollector;
DepCollectorASTListener(DependencyCollector &L) : DepCollector(L) { }
bool needsInputFileVisitation() override { return true; }
bool needsSystemInputFileVisitation() override {
return DepCollector.needSystemDependencies();
}
void visitModuleFile(StringRef Filename,
serialization::ModuleKind Kind) override {
DepCollector.maybeAddDependency(Filename, /*FromModule*/true,
/*IsSystem*/false, /*IsModuleFile*/true,
/*IsMissing*/false);
}
bool visitInputFile(StringRef Filename, bool IsSystem,
bool IsOverridden, bool IsExplicitModule) override {
if (IsOverridden || IsExplicitModule)
return true;
DepCollector.maybeAddDependency(Filename, /*FromModule*/true, IsSystem,
/*IsModuleFile*/false, /*IsMissing*/false);
return true;
}
};
} // end anonymous namespace
void DependencyCollector::maybeAddDependency(StringRef Filename,
bool FromModule, bool IsSystem,
bool IsModuleFile,
bool IsMissing) {
if (sawDependency(Filename, FromModule, IsSystem, IsModuleFile, IsMissing))
addDependency(Filename);
}
bool DependencyCollector::addDependency(StringRef Filename) {
StringRef SearchPath;
#ifdef _WIN32
// Make the search insensitive to case and separators.
llvm::SmallString<256> TmpPath = Filename;
llvm::sys::path::native(TmpPath);
std::transform(TmpPath.begin(), TmpPath.end(), TmpPath.begin(), ::tolower);
SearchPath = TmpPath.str();
#else
SearchPath = Filename;
#endif
if (Seen.insert(SearchPath).second) {
Dependencies.push_back(std::string(Filename));
return true;
}
return false;
}
static bool isSpecialFilename(StringRef Filename) {
return llvm::StringSwitch<bool>(Filename)
.Case("<built-in>", true)
.Case("<stdin>", true)
.Default(false);
}
bool DependencyCollector::sawDependency(StringRef Filename, bool FromModule,
bool IsSystem, bool IsModuleFile,
bool IsMissing) {
return !isSpecialFilename(Filename) &&
(needSystemDependencies() || !IsSystem);
}
DependencyCollector::~DependencyCollector() { }
void DependencyCollector::attachToPreprocessor(Preprocessor &PP) {
PP.addPPCallbacks(std::make_unique<DepCollectorPPCallbacks>(
*this, PP.getSourceManager(), PP.getDiagnostics()));
PP.getHeaderSearchInfo().getModuleMap().addModuleMapCallbacks(
std::make_unique<DepCollectorMMCallbacks>(*this));
}
void DependencyCollector::attachToASTReader(ASTReader &R) {
R.addListener(std::make_unique<DepCollectorASTListener>(*this));
}
DependencyFileGenerator::DependencyFileGenerator(
const DependencyOutputOptions &Opts)
: OutputFile(Opts.OutputFile), Targets(Opts.Targets),
IncludeSystemHeaders(Opts.IncludeSystemHeaders),
PhonyTarget(Opts.UsePhonyTargets),
AddMissingHeaderDeps(Opts.AddMissingHeaderDeps), SeenMissingHeader(false),
IncludeModuleFiles(Opts.IncludeModuleFiles),
OutputFormat(Opts.OutputFormat), InputFileIndex(0) {
for (const auto &ExtraDep : Opts.ExtraDeps) {
if (addDependency(ExtraDep.first))
++InputFileIndex;
}
}
void DependencyFileGenerator::attachToPreprocessor(Preprocessor &PP) {
// Disable the "file not found" diagnostic if the -MG option was given.
if (AddMissingHeaderDeps)
PP.SetSuppressIncludeNotFoundError(true);
DependencyCollector::attachToPreprocessor(PP);
}
bool DependencyFileGenerator::sawDependency(StringRef Filename, bool FromModule,
bool IsSystem, bool IsModuleFile,
bool IsMissing) {
if (IsMissing) {
// Handle the case of missing file from an inclusion directive.
if (AddMissingHeaderDeps)
return true;
SeenMissingHeader = true;
return false;
}
if (IsModuleFile && !IncludeModuleFiles)
return false;
if (isSpecialFilename(Filename))
return false;
if (IncludeSystemHeaders)
return true;
return !IsSystem;
}
void DependencyFileGenerator::finishedMainFile(DiagnosticsEngine &Diags) {
outputDependencyFile(Diags);
}
/// Print the filename, with escaping or quoting that accommodates the three
/// most likely tools that use dependency files: GNU Make, BSD Make, and
/// NMake/Jom.
///
/// BSD Make is the simplest case: It does no escaping at all. This means
/// characters that are normally delimiters, i.e. space and # (the comment
/// character) simply aren't supported in filenames.
///
/// GNU Make does allow space and # in filenames, but to avoid being treated
/// as a delimiter or comment, these must be escaped with a backslash. Because
/// backslash is itself the escape character, if a backslash appears in a
/// filename, it should be escaped as well. (As a special case, $ is escaped
/// as $$, which is the normal Make way to handle the $ character.)
/// For compatibility with BSD Make and historical practice, if GNU Make
/// un-escapes characters in a filename but doesn't find a match, it will
/// retry with the unmodified original string.
///
/// GCC tries to accommodate both Make formats by escaping any space or #
/// characters in the original filename, but not escaping backslashes. The
/// apparent intent is so that filenames with backslashes will be handled
/// correctly by BSD Make, and by GNU Make in its fallback mode of using the
/// unmodified original string; filenames with # or space characters aren't
/// supported by BSD Make at all, but will be handled correctly by GNU Make
/// due to the escaping.
///
/// A corner case that GCC gets only partly right is when the original filename
/// has a backslash immediately followed by space or #. GNU Make would expect
/// this backslash to be escaped; however GCC escapes the original backslash
/// only when followed by space, not #. It will therefore take a dependency
/// from a directive such as
/// #include "a\ b\#c.h"
/// and emit it as
/// a\\\ b\\#c.h
/// which GNU Make will interpret as
/// a\ b\
/// followed by a comment. Failing to find this file, it will fall back to the
/// original string, which probably doesn't exist either; in any case it won't
/// find
/// a\ b\#c.h
/// which is the actual filename specified by the include directive.
///
/// Clang does what GCC does, rather than what GNU Make expects.
///
/// NMake/Jom has a different set of scary characters, but wraps filespecs in
/// double-quotes to avoid misinterpreting them; see
/// https://msdn.microsoft.com/en-us/library/dd9y37ha.aspx for NMake info,
/// https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx
/// for Windows file-naming info.
static void PrintFilename(raw_ostream &OS, StringRef Filename,
DependencyOutputFormat OutputFormat) {
// Convert filename to platform native path
llvm::SmallString<256> NativePath;
llvm::sys::path::native(Filename.str(), NativePath);
if (OutputFormat == DependencyOutputFormat::NMake) {
// Add quotes if needed. These are the characters listed as "special" to
// NMake, that are legal in a Windows filespec, and that could cause
// misinterpretation of the dependency string.
if (NativePath.find_first_of(" #${}^!") != StringRef::npos)
OS << '\"' << NativePath << '\"';
else
OS << NativePath;
return;
}
assert(OutputFormat == DependencyOutputFormat::Make);
for (unsigned i = 0, e = NativePath.size(); i != e; ++i) {
if (NativePath[i] == '#') // Handle '#' the broken gcc way.
OS << '\\';
else if (NativePath[i] == ' ') { // Handle space correctly.
OS << '\\';
unsigned j = i;
while (j > 0 && NativePath[--j] == '\\')
OS << '\\';
} else if (NativePath[i] == '$') // $ is escaped by $$.
OS << '$';
OS << NativePath[i];
}
}
void DependencyFileGenerator::outputDependencyFile(DiagnosticsEngine &Diags) {
if (SeenMissingHeader) {
llvm::sys::fs::remove(OutputFile);
return;
}
std::error_code EC;
llvm::raw_fd_ostream OS(OutputFile, EC, llvm::sys::fs::OF_TextWithCRLF);
if (EC) {
Diags.Report(diag::err_fe_error_opening) << OutputFile << EC.message();
return;
}
outputDependencyFile(OS);
}
void DependencyFileGenerator::outputDependencyFile(llvm::raw_ostream &OS) {
// Write out the dependency targets, trying to avoid overly long
// lines when possible. We try our best to emit exactly the same
// dependency file as GCC (4.2), assuming the included files are the
// same.
const unsigned MaxColumns = 75;
unsigned Columns = 0;
for (StringRef Target : Targets) {
unsigned N = Target.size();
if (Columns == 0) {
Columns += N;
} else if (Columns + N + 2 > MaxColumns) {
Columns = N + 2;
OS << " \\\n ";
} else {
Columns += N + 1;
OS << ' ';
}
// Targets already quoted as needed.
OS << Target;
}
OS << ':';
Columns += 1;
// Now add each dependency in the order it was seen, but avoiding
// duplicates.
ArrayRef<std::string> Files = getDependencies();
for (StringRef File : Files) {
// Start a new line if this would exceed the column limit. Make
// sure to leave space for a trailing " \" in case we need to
// break the line on the next iteration.
unsigned N = File.size();
if (Columns + (N + 1) + 2 > MaxColumns) {
OS << " \\\n ";
Columns = 2;
}
OS << ' ';
PrintFilename(OS, File, OutputFormat);
Columns += N + 1;
}
OS << '\n';
// Create phony targets if requested.
if (PhonyTarget && !Files.empty()) {
unsigned Index = 0;
for (auto I = Files.begin(), E = Files.end(); I != E; ++I) {
if (Index++ == InputFileIndex)
continue;
OS << '\n';
PrintFilename(OS, *I, OutputFormat);
OS << ":\n";
}
}
}