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<rdar://problem/13426257> Introduce SDKSettings.plist as an input file dependency for PCH/modules. 

When we're building a precompiled header or module against an SDK on
Darwin, there will be a file SDKSettings.plist in the sysroot. Since
stat()'ing every system header on which a module or PCH file depends
is performance suicide, we instead stat() just SDKSettings.plist. This
hack works well on Darwin; it's unclear how we want to handle this on
other platforms. If there is a canonical file, we should use it; if
not, we either have to take the performance hit of stat()'ing system
headers repeatedly or roll the dice by not checking anything.

llvm-svn: 177194
This commit is contained in:
Douglas Gregor 2013-03-15 22:15:07 +00:00
parent e943ce1ace
commit 49491f7861
2 changed files with 50 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
clang/include/clang/Serialization/ASTWriter.h
View File

@ -48,6 +48,7 @@ class CXXCtorInitializer;
class FileEntry;
class FPOptions;
class HeaderSearch;
class HeaderSearchOptions;
class IdentifierResolver;
class MacroDefinition;
class OpaqueValueExpr;
@ -416,7 +417,9 @@ private:
void WriteBlockInfoBlock();
void WriteControlBlock(Preprocessor &PP, ASTContext &Context,
StringRef isysroot, const std::string &OutputFile);
void WriteInputFiles(SourceManager &SourceMgr, StringRef isysroot);
void WriteInputFiles(SourceManager &SourceMgr,
HeaderSearchOptions &HSOpts,
StringRef isysroot);
void WriteSourceManagerBlock(SourceManager &SourceMgr,
const Preprocessor &PP,
StringRef isysroot);

61
clang/lib/Serialization/ASTWriter.cpp
View File

@ -1213,11 +1213,24 @@ void ASTWriter::WriteControlBlock(Preprocessor &PP, ASTContext &Context,
Stream.EmitRecordWithBlob(AbbrevCode, Record, origDir);
}
WriteInputFiles(Context.SourceMgr, isysroot);
WriteInputFiles(Context.SourceMgr,
PP.getHeaderSearchInfo().getHeaderSearchOpts(),
isysroot);
Stream.ExitBlock();
}
void ASTWriter::WriteInputFiles(SourceManager &SourceMgr, StringRef isysroot) {
namespace {
/// \brief An input file.
struct InputFileEntry {
const FileEntry *File;
bool IsSystemFile;
bool BufferOverridden;
};
}
void ASTWriter::WriteInputFiles(SourceManager &SourceMgr,
HeaderSearchOptions &HSOpts,
StringRef isysroot) {
using namespace llvm;
Stream.EnterSubblock(INPUT_FILES_BLOCK_ID, 4);
RecordData Record;
@ -1234,7 +1247,7 @@ void ASTWriter::WriteInputFiles(SourceManager &SourceMgr, StringRef isysroot) {
// Get all ContentCache objects for files, sorted by whether the file is a
// system one or not. System files go at the back, users files at the front.
std::deque<const SrcMgr::ContentCache *> SortedFiles;
std::deque<InputFileEntry> SortedFiles;
for (unsigned I = 1, N = SourceMgr.local_sloc_entry_size(); I != N; ++I) {
// Get this source location entry.
const SrcMgr::SLocEntry *SLoc = &SourceMgr.getLocalSLocEntry(I);
@ -1247,20 +1260,38 @@ void ASTWriter::WriteInputFiles(SourceManager &SourceMgr, StringRef isysroot) {
if (!Cache->OrigEntry)
continue;
InputFileEntry Entry;
Entry.File = Cache->OrigEntry;
Entry.IsSystemFile = Cache->IsSystemFile;
Entry.BufferOverridden = Cache->BufferOverridden;
if (Cache->IsSystemFile)
SortedFiles.push_back(Cache);
SortedFiles.push_back(Entry);
else
SortedFiles.push_front(Cache);
SortedFiles.push_front(Entry);
}
// If we have an isysroot for a Darwin SDK, include its SDKSettings.plist in
// the set of (non-system) input files. This is simple heuristic for
// detecting whether the system headers may have changed, because it is too
// expensive to stat() all of the system headers.
FileManager &FileMgr = SourceMgr.getFileManager();
if (!HSOpts.Sysroot.empty()) {
llvm::SmallString<128> SDKSettingsFileName(HSOpts.Sysroot);
llvm::sys::path::append(SDKSettingsFileName, "SDKSettings.plist");
if (const FileEntry *SDKSettingsFile = FileMgr.getFile(SDKSettingsFileName)) {
InputFileEntry Entry = { SDKSettingsFile, false, false };
SortedFiles.push_front(Entry);
}
}
unsigned UserFilesNum = 0;
// Write out all of the input files.
std::vector<uint32_t> InputFileOffsets;
for (std::deque<const SrcMgr::ContentCache *>::iterator
for (std::deque<InputFileEntry>::iterator
I = SortedFiles.begin(), E = SortedFiles.end(); I != E; ++I) {
const SrcMgr::ContentCache *Cache = *I;
const InputFileEntry &Entry = *I;
uint32_t &InputFileID = InputFileIDs[Cache->OrigEntry];
uint32_t &InputFileID = InputFileIDs[Entry.File];
if (InputFileID != 0)
continue; // already recorded this file.
@ -1269,7 +1300,7 @@ void ASTWriter::WriteInputFiles(SourceManager &SourceMgr, StringRef isysroot) {
InputFileID = InputFileOffsets.size();
if (!Cache->IsSystemFile)
if (!Entry.IsSystemFile)
++UserFilesNum;
Record.clear();
@ -1277,19 +1308,19 @@ void ASTWriter::WriteInputFiles(SourceManager &SourceMgr, StringRef isysroot) {
Record.push_back(InputFileOffsets.size());
// Emit size/modification time for this file.
Record.push_back(Cache->OrigEntry->getSize());
Record.push_back(Cache->OrigEntry->getModificationTime());
Record.push_back(Entry.File->getSize());
Record.push_back(Entry.File->getModificationTime());
// Whether this file was overridden.
Record.push_back(Cache->BufferOverridden);
Record.push_back(Entry.BufferOverridden);
// Turn the file name into an absolute path, if it isn't already.
const char *Filename = Cache->OrigEntry->getName();
const char *Filename = Entry.File->getName();
SmallString<128> FilePath(Filename);
// Ask the file manager to fixup the relative path for us. This will
// honor the working directory.
SourceMgr.getFileManager().FixupRelativePath(FilePath);
FileMgr.FixupRelativePath(FilePath);
// FIXME: This call to make_absolute shouldn't be necessary, the
// call to FixupRelativePath should always return an absolute path.
@ -1300,7 +1331,7 @@ void ASTWriter::WriteInputFiles(SourceManager &SourceMgr, StringRef isysroot) {
Stream.EmitRecordWithBlob(IFAbbrevCode, Record, Filename);
}
Stream.ExitBlock();
// Create input file offsets abbreviation.