Add a new flag, __tsan_mutex_not_static, which has the opposite sense
of __tsan_mutex_linker_init. When the new __tsan_mutex_not_static flag
is passed to __tsan_mutex_destroy, tsan ignores the destruction unless
the mutex was also created with the __tsan_mutex_not_static flag.
This is useful for constructors that otherwise woud set
__tsan_mutex_linker_init but cannot, because they are declared constexpr.
Google has a custom mutex with two constructors, a "linker initialized"
constructor that relies on zero-initialization and sets
__tsan_mutex_linker_init, and a normal one which sets no tsan flags.
The "linker initialized" constructor is morally constexpr, but we can't
declare it constexpr because of the need to call into tsan as a side effect.
With this new flag, the normal c'tor can set __tsan_mutex_not_static,
the "linker initialized" constructor can rely on tsan's lazy initialization,
and __tsan_mutex_destroy can still handle both cases correctly.
Author: Greg Falcon (gfalcon)
Reviewed in: https://reviews.llvm.org/D39095
llvm-svn: 316209
This patch allows the Swift compiler to emit calls to `__tsan_external_write` before starting any modifying access, which will cause TSan to detect races on arrays, dictionaries and other classes defined in non-instrumented modules. Races on collections from the Swift standard library and user-defined structs and a frequent cause of subtle bugs and it's important that TSan detects those on top of existing LLVM IR instrumentation, which already detects races in direct memory accesses.
Differential Revision: https://reviews.llvm.org/D31630
llvm-svn: 302050
For a linker init mutex with lazy flag setup
(no __tsan_mutex_create call), it is possible that
no lock/unlock happened before the destroy call.
Then when destroy runs we still don't know that
it is a linker init mutex and will emulate a memory write.
This in turn can lead to false positives as the mutex
is in fact linker initialized.
Support linker init flag in destroy annotation to resolve this.
llvm-svn: 301795
There are several problems with the current annotations (AnnotateRWLockCreate and friends):
- they don't fully support deadlock detection (we need a hook _before_ mutex lock)
- they don't support insertion of random artificial delays to perturb execution (again we need a hook _before_ mutex lock)
- they don't support setting extended mutex attributes like read/write reentrancy (only "linker init" was bolted on)
- they don't support setting mutex attributes if a mutex don't have a "constructor" (e.g. static, Java, Go mutexes)
- they don't ignore synchronization inside of lock/unlock operations which leads to slowdown and false negatives
The new annotations solve of the above problems. See tsan_interface.h for the interface specification and comments.
Reviewed in https://reviews.llvm.org/D31093
llvm-svn: 298809
Dmitry Vyukov