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Fix use-after-free and spurious error during module load 

FileManager::invalidateCache is not safe to call when there may be
existing references to the file. What module load failure needs is
to refresh so stale stat() info isn't stored.

This may be the last user of invalidateCache; I'll take a look and
remove it if possible in a future commit.

This caused a use-after-free error as well as a spurious error message
that a module was "found in both 'X.pcm' and 'X.pcm'" in some cases.

llvm-svn: 209138
This commit is contained in:
Ben Langmuir 2014-05-19 16:13:45 +00:00
parent d71b6dfd85
commit ca39214f4e
2 changed files with 38 additions and 2 deletions
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15
clang/lib/Serialization/ModuleManager.cpp
View File

@ -152,9 +152,20 @@ void ModuleManager::removeModules(ModuleIterator first, ModuleIterator last,
// Delete the modules and erase them from the various structures.
for (ModuleIterator victim = first; victim != last; ++victim) {
Modules.erase((*victim)->File);
const FileEntry *F = (*victim)->File;
Modules.erase(F);
// Refresh the stat() information for the module file so stale information
// doesn't get stored accidentally.
vfs::Status UpdatedStat;
if (FileMgr.getNoncachedStatValue(F->getName(), UpdatedStat)) {
llvm::report_fatal_error(Twine("module file '") + F->getName() +
"' removed after it has been used");
} else {
FileMgr.modifyFileEntry(const_cast<FileEntry *>(F), UpdatedStat.getSize(),
UpdatedStat.getLastModificationTime().toEpochTime());
}
FileMgr.invalidateCache((*victim)->File);
if (modMap) {
StringRef ModuleName = (*victim)->ModuleName;
if (Module *mod = modMap->findModule(ModuleName)) {

25
clang/test/Modules/load-after-failure.m Normal file
View File

@ -0,0 +1,25 @@
// REQUIRES: shell
// RUN: rm -rf %t
// RUN: mkdir -p %t
// RUN: echo '@import B;' > %t/A.h
// RUN: echo '@import C;' > %t/B.h
// RUN: echo '@import D;' >> %t/B.h
// RUN: echo '// C.h' > %t/C.h
// RUN: echo '// D.h' > %t/D.h
// RUN: echo 'module A { header "A.h" }' > %t/module.modulemap
// RUN: echo 'module B { header "B.h" }' >> %t/module.modulemap
// RUN: echo 'module C { header "C.h" }' >> %t/module.modulemap
// RUN: echo 'module D { header "D.h" }' >> %t/module.modulemap
// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t -I %t %s -verify
// RUN: echo " " >> %t/D.h
// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t -I %t %s -verify
// expected-no-diagnostics
@import C;
@import A;
@import C;
// When compiling A, C will be be loaded then removed when D fails. Ensure
// this does not cause problems importing C again later.