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//===--- ModuleDependencyCollector.cpp - Collect module dependencies ------===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
// Collect the dependencies of a set of modules.
#include "clang/Basic/CharInfo.h"
#include "clang/Frontend/Utils.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Serialization/ASTReader.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/raw_ostream.h"
using namespace clang;
namespace {
/// Private implementations for ModuleDependencyCollector
class ModuleDependencyListener : public ASTReaderListener {
ModuleDependencyCollector &Collector;
ModuleDependencyListener(ModuleDependencyCollector &Collector)
: Collector(Collector) {}
bool needsInputFileVisitation() override { return true; }
bool needsSystemInputFileVisitation() override { return true; }
bool visitInputFile(StringRef Filename, bool IsSystem, bool IsOverridden,
bool IsExplicitModule) override {
return true;
struct ModuleDependencyPPCallbacks : public PPCallbacks {
ModuleDependencyCollector &Collector;
SourceManager &SM;
ModuleDependencyPPCallbacks(ModuleDependencyCollector &Collector,
SourceManager &SM)
: Collector(Collector), SM(SM) {}
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)
struct ModuleDependencyMMCallbacks : public ModuleMapCallbacks {
ModuleDependencyCollector &Collector;
ModuleDependencyMMCallbacks(ModuleDependencyCollector &Collector)
: Collector(Collector) {}
void moduleMapAddHeader(StringRef HeaderPath) override {
if (llvm::sys::path::is_absolute(HeaderPath))
void moduleMapAddUmbrellaHeader(FileManager *FileMgr,
const FileEntry *Header) override {
StringRef HeaderFilename = Header->getName();
// The FileManager can find and cache the symbolic link for a framework
// header before its real path, this means a module can have some of its
// headers to use other paths. Although this is usually not a problem, it's
// inconsistent, and not collecting the original path header leads to
// umbrella clashes while rebuilding modules in the crash reproducer. For
// example:
// ApplicationServices.framework/Frameworks/ImageIO.framework/ImageIO.h
// instead of:
// ImageIO.framework/ImageIO.h
// FIXME: this shouldn't be necessary once we have FileName instances
// around instead of FileEntry ones. For now, make sure we collect all
// that we need for the reproducer to work correctly.
StringRef UmbreallDirFromHeader =
StringRef UmbrellaDir = Header->getDir()->getName();
if (!UmbrellaDir.equals(UmbreallDirFromHeader)) {
SmallString<128> AltHeaderFilename;
llvm::sys::path::append(AltHeaderFilename, UmbrellaDir,
if (FileMgr->getFile(AltHeaderFilename))
// TODO: move this to Support/Path.h and check for HAVE_REALPATH?
static bool real_path(StringRef SrcPath, SmallVectorImpl<char> &RealPath) {
char CanonicalPath[PATH_MAX];
// TODO: emit a warning in case this fails...?
if (!realpath(SrcPath.str().c_str(), CanonicalPath))
return false;
SmallString<256> RPath(CanonicalPath);
return true;
// FIXME: Add support for systems without realpath.
return false;
void ModuleDependencyCollector::attachToASTReader(ASTReader &R) {
void ModuleDependencyCollector::attachToPreprocessor(Preprocessor &PP) {
*this, PP.getSourceManager()));
static bool isCaseSensitivePath(StringRef Path) {
SmallString<256> TmpDest = Path, UpperDest, RealDest;
// Remove component traversals, links, etc.
if (!real_path(Path, TmpDest))
return true; // Current default value in vfs.yaml
Path = TmpDest;
// Change path to all upper case and ask for its real path, if the latter
// exists and is equal to Path, it's not case sensitive. Default to case
// sensitive in the absense of realpath, since this is what the VFSWriter
// already expects when sensitivity isn't setup.
for (auto &C : Path)
if (real_path(UpperDest, RealDest) && Path.equals(RealDest))
return false;
return true;
void ModuleDependencyCollector::writeFileMap() {
if (Seen.empty())
StringRef VFSDir = getDest();
// Default to use relative overlay directories in the VFS yaml file. This
// allows crash reproducer scripts to work across machines.
// Do not ignore non existent contents otherwise we might skip something
// that should have been collected here.
// Explicitly set case sensitivity for the YAML writer. For that, find out
// the sensitivity at the path where the headers all collected to.
// Do not rely on real path names when executing the crash reproducer scripts
// since we only want to actually use the files we have on the VFS cache.
std::error_code EC;
SmallString<256> YAMLPath = VFSDir;
llvm::sys::path::append(YAMLPath, "vfs.yaml");
llvm::raw_fd_ostream OS(YAMLPath, EC, llvm::sys::fs::F_Text);
if (EC) {
HasErrors = true;
bool ModuleDependencyCollector::getRealPath(StringRef SrcPath,
SmallVectorImpl<char> &Result) {
using namespace llvm::sys;
SmallString<256> RealPath;
StringRef FileName = path::filename(SrcPath);
std::string Dir = path::parent_path(SrcPath).str();
auto DirWithSymLink = SymLinkMap.find(Dir);
// Use real_path to fix any symbolic link component present in a path.
// Computing the real path is expensive, cache the search through the
// parent path directory.
if (DirWithSymLink == SymLinkMap.end()) {
if (!real_path(Dir, RealPath))
return false;
SymLinkMap[Dir] = RealPath.str();
} else {
RealPath = DirWithSymLink->second;
path::append(RealPath, FileName);
return true;
std::error_code ModuleDependencyCollector::copyToRoot(StringRef Src,
StringRef Dst) {
using namespace llvm::sys;
// We need an absolute src path to append to the root.
SmallString<256> AbsoluteSrc = Src;
// Canonicalize src to a native path to avoid mixed separator styles.
// Remove redundant leading "./" pieces and consecutive separators.
AbsoluteSrc = path::remove_leading_dotslash(AbsoluteSrc);
// Canonicalize the source path by removing "..", "." components.
SmallString<256> VirtualPath = AbsoluteSrc;
path::remove_dots(VirtualPath, /*remove_dot_dot=*/true);
// If a ".." component is present after a symlink component, remove_dots may
// lead to the wrong real destination path. Let the source be canonicalized
// like that but make sure we always use the real path for the destination.
SmallString<256> CopyFrom;
if (!getRealPath(AbsoluteSrc, CopyFrom))
CopyFrom = VirtualPath;
SmallString<256> CacheDst = getDest();
if (Dst.empty()) {
// The common case is to map the virtual path to the same path inside the
// cache.
path::append(CacheDst, path::relative_path(CopyFrom));
} else {
// When collecting entries from input vfsoverlays, copy the external
// contents into the cache but still map from the source.
if (!fs::exists(Dst))
return std::error_code();
path::append(CacheDst, Dst);
CopyFrom = Dst;
// Copy the file into place.
if (std::error_code EC = fs::create_directories(path::parent_path(CacheDst),
return EC;
if (std::error_code EC = fs::copy_file(CopyFrom, CacheDst))
return EC;
// Always map a canonical src path to its real path into the YAML, by doing
// this we map different virtual src paths to the same entry in the VFS
// overlay, which is a way to emulate symlink inside the VFS; this is also
// needed for correctness, not doing that can lead to module redifinition
// errors.
addFileMapping(VirtualPath, CacheDst);
return std::error_code();
void ModuleDependencyCollector::addFile(StringRef Filename, StringRef FileDst) {
if (insertSeen(Filename))
if (copyToRoot(Filename, FileDst))
HasErrors = true;