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//===--- DependencyFile.cpp - Generate dependency file --------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// 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/LexDiagnostic.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;
DepCollectorPPCallbacks(DependencyCollector &L, SourceManager &SM)
: DepCollector(L), SM(SM) { }
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!
const FileEntry *FE =
SM.getFileEntryForID(SM.getFileID(SM.getExpansionLoc(Loc)));
if (!FE)
return;
StringRef Filename =
llvm::sys::path::remove_leading_dotslash(FE->getName());
DepCollector.maybeAddDependency(Filename, /*FromModule*/false,
isSystem(FileType),
/*IsModuleFile*/false, /*IsMissing*/false);
}
void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
StringRef FileName, bool IsAngled,
CharSourceRange FilenameRange, const FileEntry *File,
StringRef SearchPath, StringRef RelativePath,
const Module *Imported) override {
if (!File)
DepCollector.maybeAddDependency(FileName, /*FromModule*/false,
/*IsSystem*/false, /*IsModuleFile*/false,
/*IsMissing*/true);
// Files that actually exist are handled by FileChanged.
}
void EndOfMainFile() override {
DepCollector.finishedMainFile();
}
};
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 (Seen.insert(Filename).second &&
sawDependency(Filename, FromModule, IsSystem, IsModuleFile, IsMissing))
Dependencies.push_back(Filename);
}
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(
llvm::make_unique<DepCollectorPPCallbacks>(*this, PP.getSourceManager()));
PP.getHeaderSearchInfo().getModuleMap().addModuleMapCallbacks(
llvm::make_unique<DepCollectorMMCallbacks>(*this));
}
void DependencyCollector::attachToASTReader(ASTReader &R) {
R.addListener(llvm::make_unique<DepCollectorASTListener>(*this));
}
namespace {
/// Private implementation for DependencyFileGenerator
class DFGImpl : public PPCallbacks {
std::vector<std::string> Files;
llvm::StringSet<> FilesSet;
const Preprocessor *PP;
std::string OutputFile;
std::vector<std::string> Targets;
bool IncludeSystemHeaders;
bool PhonyTarget;
bool AddMissingHeaderDeps;
bool SeenMissingHeader;
bool IncludeModuleFiles;
DependencyOutputFormat OutputFormat;
private:
bool FileMatchesDepCriteria(const char *Filename,
SrcMgr::CharacteristicKind FileType);
void OutputDependencyFile();
public:
DFGImpl(const Preprocessor *_PP, const DependencyOutputOptions &Opts)
: PP(_PP), OutputFile(Opts.OutputFile), Targets(Opts.Targets),
IncludeSystemHeaders(Opts.IncludeSystemHeaders),
PhonyTarget(Opts.UsePhonyTargets),
AddMissingHeaderDeps(Opts.AddMissingHeaderDeps),
SeenMissingHeader(false),
IncludeModuleFiles(Opts.IncludeModuleFiles),
OutputFormat(Opts.OutputFormat) {
for (const auto &ExtraDep : Opts.ExtraDeps) {
AddFilename(ExtraDep);
}
}
void FileChanged(SourceLocation Loc, FileChangeReason Reason,
SrcMgr::CharacteristicKind FileType,
FileID PrevFID) override;
void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
StringRef FileName, bool IsAngled,
CharSourceRange FilenameRange, const FileEntry *File,
StringRef SearchPath, StringRef RelativePath,
const Module *Imported) override;
void EndOfMainFile() override {
OutputDependencyFile();
}
void AddFilename(StringRef Filename);
bool includeSystemHeaders() const { return IncludeSystemHeaders; }
bool includeModuleFiles() const { return IncludeModuleFiles; }
};
class DFGMMCallback : public ModuleMapCallbacks {
DFGImpl &Parent;
public:
DFGMMCallback(DFGImpl &Parent) : Parent(Parent) {}
void moduleMapFileRead(SourceLocation Loc, const FileEntry &Entry,
bool IsSystem) override {
if (!IsSystem || Parent.includeSystemHeaders())
Parent.AddFilename(Entry.getName());
}
};
class DFGASTReaderListener : public ASTReaderListener {
DFGImpl &Parent;
public:
DFGASTReaderListener(DFGImpl &Parent)
: Parent(Parent) { }
bool needsInputFileVisitation() override { return true; }
bool needsSystemInputFileVisitation() override {
return Parent.includeSystemHeaders();
}
void visitModuleFile(StringRef Filename,
serialization::ModuleKind Kind) override;
bool visitInputFile(StringRef Filename, bool isSystem,
bool isOverridden, bool isExplicitModule) override;
};
}
DependencyFileGenerator::DependencyFileGenerator(void *Impl)
: Impl(Impl) { }
DependencyFileGenerator *DependencyFileGenerator::CreateAndAttachToPreprocessor(
clang::Preprocessor &PP, const clang::DependencyOutputOptions &Opts) {
if (Opts.Targets.empty()) {
PP.getDiagnostics().Report(diag::err_fe_dependency_file_requires_MT);
return nullptr;
}
// Disable the "file not found" diagnostic if the -MG option was given.
if (Opts.AddMissingHeaderDeps)
PP.SetSuppressIncludeNotFoundError(true);
DFGImpl *Callback = new DFGImpl(&PP, Opts);
PP.addPPCallbacks(std::unique_ptr<PPCallbacks>(Callback));
PP.getHeaderSearchInfo().getModuleMap().addModuleMapCallbacks(
llvm::make_unique<DFGMMCallback>(*Callback));
return new DependencyFileGenerator(Callback);
}
void DependencyFileGenerator::AttachToASTReader(ASTReader &R) {
DFGImpl *I = reinterpret_cast<DFGImpl *>(Impl);
assert(I && "missing implementation");
R.addListener(llvm::make_unique<DFGASTReaderListener>(*I));
}
/// FileMatchesDepCriteria - Determine whether the given Filename should be
/// considered as a dependency.
bool DFGImpl::FileMatchesDepCriteria(const char *Filename,
SrcMgr::CharacteristicKind FileType) {
if (isSpecialFilename(Filename))
return false;
if (IncludeSystemHeaders)
return true;
return !isSystem(FileType);
}
void DFGImpl::FileChanged(SourceLocation Loc,
FileChangeReason Reason,
SrcMgr::CharacteristicKind FileType,
FileID PrevFID) {
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!
SourceManager &SM = PP->getSourceManager();
const FileEntry *FE =
SM.getFileEntryForID(SM.getFileID(SM.getExpansionLoc(Loc)));
if (!FE) return;
StringRef Filename = FE->getName();
if (!FileMatchesDepCriteria(Filename.data(), FileType))
return;
AddFilename(llvm::sys::path::remove_leading_dotslash(Filename));
}
void DFGImpl::InclusionDirective(SourceLocation HashLoc,
const Token &IncludeTok,
StringRef FileName,
bool IsAngled,
CharSourceRange FilenameRange,
const FileEntry *File,
StringRef SearchPath,
StringRef RelativePath,
const Module *Imported) {
if (!File) {
if (AddMissingHeaderDeps)
AddFilename(FileName);
else
SeenMissingHeader = true;
}
}
void DFGImpl::AddFilename(StringRef Filename) {
if (FilesSet.insert(Filename).second)
Files.push_back(Filename);
}
/// 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) {
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 (Filename.find_first_of(" #${}^!") != StringRef::npos)
OS << '\"' << Filename << '\"';
else
OS << Filename;
return;
}
assert(OutputFormat == DependencyOutputFormat::Make);
for (unsigned i = 0, e = Filename.size(); i != e; ++i) {
if (Filename[i] == '#') // Handle '#' the broken gcc way.
OS << '\\';
else if (Filename[i] == ' ') { // Handle space correctly.
OS << '\\';
unsigned j = i;
while (j > 0 && Filename[--j] == '\\')
OS << '\\';
} else if (Filename[i] == '$') // $ is escaped by $$.
OS << '$';
OS << Filename[i];
}
}
void DFGImpl::OutputDependencyFile() {
if (SeenMissingHeader) {
llvm::sys::fs::remove(OutputFile);
return;
}
std::error_code EC;
llvm::raw_fd_ostream OS(OutputFile, EC, llvm::sys::fs::F_Text);
if (EC) {
PP->getDiagnostics().Report(diag::err_fe_error_opening) << OutputFile
<< EC.message();
return;
}
// 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.
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()) {
// Skip the first entry, this is always the input file itself.
for (auto I = Files.begin() + 1, E = Files.end(); I != E; ++I) {
OS << '\n';
PrintFilename(OS, *I, OutputFormat);
OS << ":\n";
}
}
}
bool DFGASTReaderListener::visitInputFile(llvm::StringRef Filename,
bool IsSystem, bool IsOverridden,
bool IsExplicitModule) {
assert(!IsSystem || needsSystemInputFileVisitation());
if (IsOverridden || IsExplicitModule)
return true;
Parent.AddFilename(Filename);
return true;
}
void DFGASTReaderListener::visitModuleFile(llvm::StringRef Filename,
serialization::ModuleKind Kind) {
if (Parent.includeModuleFiles())
Parent.AddFilename(Filename);
}