Implement our own future and use that for FileArchive::preload().
std::promise and std::future in old version of libstdc++ are buggy.
I think that's the reason why LLD tests were flaky on Ubuntu 13
buildbots until we disabled file preloading.
In this patch, I implemented very simple future and used that in
FileArchive. Compared to std::promise and std::future, it lacks
many features, but should serve our purpose.
http://reviews.llvm.org/D8025
llvm-svn: 231153
diff --git a/lld/lib/Core/Resolver.cpp b/lld/lib/Core/Resolver.cpp
index 7153279..4e5ea01 100644
--- a/lld/lib/Core/Resolver.cpp
+++ b/lld/lib/Core/Resolver.cpp
@@ -31,9 +31,12 @@
bool undefAdded = false;
for (const DefinedAtom *atom : file.defined())
doDefinedAtom(*atom);
- for (const UndefinedAtom *atom : file.undefined())
- if (doUndefinedAtom(*atom))
+ for (const UndefinedAtom *atom : file.undefined()) {
+ if (doUndefinedAtom(*atom)) {
undefAdded = true;
+ maybePreloadArchiveMember(atom->name());
+ }
+ }
for (const SharedLibraryAtom *atom : file.sharedLibrary())
doSharedLibraryAtom(*atom);
for (const AbsoluteAtom *atom : file.absolute())
@@ -230,6 +233,17 @@
doDefinedAtom(*newAtom);
}
+// Instantiate an archive file member if there's a file containing a
+// defined symbol for a given symbol name. Instantiation is done in a
+// different worker thread and has no visible side effect.
+void Resolver::maybePreloadArchiveMember(StringRef sym) {
+ auto it = _archiveMap.find(sym);
+ if (it == _archiveMap.end())
+ return;
+ ArchiveLibraryFile *archive = it->second;
+ archive->preload(_ctx.getTaskGroup(), sym);
+}
+
// Returns true if at least one of N previous files has created an
// undefined symbol.
bool Resolver::undefinesAdded(int begin, int end) {