Implement caching of stat() calls for precompiled headers, which is
essentially the same thing we do with pretokenized headers. stat()
caching improves performance of the Cocoa-prefixed "Hello, World" by
45%.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@70223 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/PCHReader.cpp b/lib/Frontend/PCHReader.cpp
index f26cd84..f87252a 100644
--- a/lib/Frontend/PCHReader.cpp
+++ b/lib/Frontend/PCHReader.cpp
@@ -31,6 +31,7 @@
#include "llvm/Support/MemoryBuffer.h"
#include <algorithm>
#include <cstdio>
+#include <sys/stat.h>
using namespace clang;
//===----------------------------------------------------------------------===//
@@ -43,7 +44,8 @@
IdentifierOffsets(0),
MethodPoolLookupTable(0), MethodPoolLookupTableData(0),
TotalSelectorsInMethodPool(0), SelectorOffsets(0),
- TotalNumSelectors(0), NumSLocEntriesRead(0), NumStatementsRead(0),
+ TotalNumSelectors(0), NumStatHits(0), NumStatMisses(0),
+ NumSLocEntriesRead(0), NumStatementsRead(0),
NumMacrosRead(0), NumMethodPoolSelectorsRead(0), NumMethodPoolMisses(0),
NumLexicalDeclContextsRead(0), NumVisibleDeclContextsRead(0) { }
@@ -377,6 +379,10 @@
return true;
}
+//===----------------------------------------------------------------------===//
+// Source Manager Deserialization
+//===----------------------------------------------------------------------===//
+
/// \brief Read the line table in the source manager block.
/// \returns true if ther was an error.
static bool ParseLineTable(SourceManager &SourceMgr,
@@ -420,6 +426,115 @@
return false;
}
+namespace {
+
+class VISIBILITY_HIDDEN PCHStatData {
+public:
+ const bool hasStat;
+ const ino_t ino;
+ const dev_t dev;
+ const mode_t mode;
+ const time_t mtime;
+ const off_t size;
+
+ PCHStatData(ino_t i, dev_t d, mode_t mo, time_t m, off_t s)
+ : hasStat(true), ino(i), dev(d), mode(mo), mtime(m), size(s) {}
+
+ PCHStatData()
+ : hasStat(false), ino(0), dev(0), mode(0), mtime(0), size(0) {}
+};
+
+class VISIBILITY_HIDDEN PCHStatLookupTrait {
+ public:
+ typedef const char *external_key_type;
+ typedef const char *internal_key_type;
+
+ typedef PCHStatData data_type;
+
+ static unsigned ComputeHash(const char *path) {
+ return BernsteinHash(path);
+ }
+
+ static internal_key_type GetInternalKey(const char *path) { return path; }
+
+ static bool EqualKey(internal_key_type a, internal_key_type b) {
+ return strcmp(a, b) == 0;
+ }
+
+ static std::pair<unsigned, unsigned>
+ ReadKeyDataLength(const unsigned char*& d) {
+ unsigned KeyLen = (unsigned) clang::io::ReadUnalignedLE16(d);
+ unsigned DataLen = (unsigned) *d++;
+ return std::make_pair(KeyLen + 1, DataLen);
+ }
+
+ static internal_key_type ReadKey(const unsigned char *d, unsigned) {
+ return (const char *)d;
+ }
+
+ static data_type ReadData(const internal_key_type, const unsigned char *d,
+ unsigned /*DataLen*/) {
+ using namespace clang::io;
+
+ if (*d++ == 1)
+ return data_type();
+
+ ino_t ino = (ino_t) ReadUnalignedLE32(d);
+ dev_t dev = (dev_t) ReadUnalignedLE32(d);
+ mode_t mode = (mode_t) ReadUnalignedLE16(d);
+ time_t mtime = (time_t) ReadUnalignedLE64(d);
+ off_t size = (off_t) ReadUnalignedLE64(d);
+ return data_type(ino, dev, mode, mtime, size);
+ }
+};
+
+/// \brief stat() cache for precompiled headers.
+///
+/// This cache is very similar to the stat cache used by pretokenized
+/// headers.
+class VISIBILITY_HIDDEN PCHStatCache : public StatSysCallCache {
+ typedef OnDiskChainedHashTable<PCHStatLookupTrait> CacheTy;
+ CacheTy *Cache;
+
+ unsigned &NumStatHits, &NumStatMisses;
+public:
+ PCHStatCache(const unsigned char *Buckets,
+ const unsigned char *Base,
+ unsigned &NumStatHits,
+ unsigned &NumStatMisses)
+ : Cache(0), NumStatHits(NumStatHits), NumStatMisses(NumStatMisses) {
+ Cache = CacheTy::Create(Buckets, Base);
+ }
+
+ ~PCHStatCache() { delete Cache; }
+
+ int stat(const char *path, struct stat *buf) {
+ // Do the lookup for the file's data in the PCH file.
+ CacheTy::iterator I = Cache->find(path);
+
+ // If we don't get a hit in the PCH file just forward to 'stat'.
+ if (I == Cache->end()) {
+ ++NumStatMisses;
+ return ::stat(path, buf);
+ }
+
+ ++NumStatHits;
+ PCHStatData Data = *I;
+
+ if (!Data.hasStat)
+ return 1;
+
+ buf->st_ino = Data.ino;
+ buf->st_dev = Data.dev;
+ buf->st_mtime = Data.mtime;
+ buf->st_mode = Data.mode;
+ buf->st_size = Data.size;
+ return 0;
+ }
+};
+} // end anonymous namespace
+
+
/// \brief Read the source manager block
PCHReader::PCHReadResult PCHReader::ReadSourceManagerBlock() {
using namespace SrcMgr;
@@ -916,6 +1031,13 @@
return Result;
}
break;
+
+ case pch::STAT_CACHE:
+ PP.getFileManager().setStatCache(
+ new PCHStatCache((const unsigned char *)BlobStart + Record[0],
+ (const unsigned char *)BlobStart,
+ NumStatHits, NumStatMisses));
+ break;
}
}
Error("Premature end of bitstream");
@@ -1505,6 +1627,8 @@
SelectorsLoaded.end(),
Selector());
+ std::fprintf(stderr, " %u stat cache hits\n", NumStatHits);
+ std::fprintf(stderr, " %u stat cache misses\n", NumStatMisses);
if (TotalNumSLocEntries)
std::fprintf(stderr, " %u/%u source location entries read (%f%%)\n",
NumSLocEntriesRead, TotalNumSLocEntries,