LTO: Try to open cache files before renaming them.
It appears that a potential race between the cache client and the cache
pruner that I thought was unlikely actually happened in practice [1].
Try to avoid the race condition by opening the temporary file before
renaming it. Do this only on non-Windows platforms because we cannot
rename open files on Windows using the sys::fs::rename function.
[1] https://luci-logdog.appspot.com/v/?s=chromium%2Fbb%2Fchromium.memory%2FLinux_CFI%2F1610%2F%2B%2Frecipes%2Fsteps%2Fcompile%2F0%2Fstdout
Differential Revision: https://reviews.llvm.org/D37410
llvm-svn: 312567
diff --git a/lld/ELF/LTO.cpp b/lld/ELF/LTO.cpp
index 751062a..561494e 100644
--- a/lld/ELF/LTO.cpp
+++ b/lld/ELF/LTO.cpp
@@ -175,9 +175,8 @@
if (!Config->ThinLTOCacheDir.empty())
Cache = check(
lto::localCache(Config->ThinLTOCacheDir,
- [&](size_t Task, std::unique_ptr<MemoryBuffer> MB) {
- Files[Task] = std::move(MB);
- }));
+ [&](size_t Task, std::unique_ptr<MemoryBuffer> MB,
+ StringRef Path) { Files[Task] = std::move(MB); }));
checkError(LTOObj->run(
[&](size_t Task) {