llvm-project/clang/test/Modules/system-out-of-date-test.m

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Reapply "Modules: Cache PCMs in memory and avoid a use-after-free" This reverts commit r298185, effectively reapplying r298165, after fixing the new unit tests (PR32338). The memory buffer generator doesn't null-terminate the MemoryBuffer it creates; this version of the commit informs getMemBuffer about that to avoid the assert. Original commit message follows: ---- Clang's internal build system for implicit modules uses lock files to ensure that after a process writes a PCM it will read the same one back in (without contention from other -cc1 commands). Since PCMs are read from disk repeatedly while invalidating, building, and importing, the lock is not released quickly. Furthermore, the LockFileManager is not robust in every environment. Other -cc1 commands can stall until timeout (after about eight minutes). This commit changes the lock file from being necessary for correctness to a (possibly dubious) performance hack. The remaining benefit is to reduce duplicate work in competing -cc1 commands which depend on the same module. Follow-up commits will change the internal build system to continue after a timeout, and reduce the timeout. Perhaps we should reconsider blocking at all. This also fixes a use-after-free, when one part of a compilation validates a PCM and starts using it, and another tries to swap out the PCM for something new. The PCMCache is a new type called MemoryBufferCache, which saves memory buffers based on their filename. Its ownership is shared by the CompilerInstance and ModuleManager. - The ModuleManager stores PCMs there that it loads from disk, never touching the disk if the cache is hot. - When modules fail to validate, they're removed from the cache. - When a CompilerInstance is spawned to build a new module, each already-loaded PCM is assumed to be valid, and is frozen to avoid the use-after-free. - Any newly-built module is written directly to the cache to avoid the round-trip to the filesystem, making lock files unnecessary for correctness. Original patch by Manman Ren; most testcases by Adrian Prantl! llvm-svn: 298278
2017-03-21 01:58:26 +08:00
// RUN: rm -rf %t.cache
// RUN: echo '@import X;' | \
// RUN: %clang_cc1 -fmodules -fimplicit-module-maps \
// RUN: -fmodules-cache-path=%t.cache -I%S/Inputs/system-out-of-date \
// RUN: -fsyntax-only -x objective-c -
//
// Build something with different diagnostic options.
// RUN: %clang_cc1 -fmodules -fimplicit-module-maps \
// RUN: -fmodules-cache-path=%t.cache -I%S/Inputs/system-out-of-date \
// RUN: -fsyntax-only %s -Wnon-modular-include-in-framework-module \
// RUN: -Werror=non-modular-include-in-framework-module 2>&1 \
// RUN: | FileCheck %s
@import X;
#import <Z.h>
// CHECK: While building module 'Z' imported from
// CHECK: {{.*}}Y-{{.*}}pcm' was validated as a system module and is now being imported as a non-system module