Add TSAN acquire/release calls to runtime/cgo to match the ones
generated by cgo. This avoids a false positive race around the malloc
memory used in runtime/cgo when other goroutines are simultaneously
calling malloc and free from cgo.
These new calls will only be used when building with CGO_CFLAGS and
CGO_LDFLAGS set to -fsanitize=thread, which becomes a requirement to
avoid all false positives when using TSAN. These are needed not just
for runtime/cgo, but also for any runtime package that uses cgo (such as
net and os/user).
Add an unused attribute to the _cgo_tsan_acquire and _cgo_tsan_release
functions, in case there are no actual cgo function calls.
Add a test that checks that setting CGO_CFLAGS/CGO_LDFLAGS avoids a
false positive report when using os/user.
Change-Id: I0905c644ff7f003b6718aac782393fa219514c48
Reviewed-on: https://go-review.googlesource.com/23492
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Acquire and release the TSAN synchronization point when calling malloc,
just as we do when calling any other C function. If we don't do this,
TSAN will report false positive errors about races calling malloc and
free.
We used to have a special code path for malloc and free, going through
the runtime functions cmalloc and cfree. The special code path for cfree
was no longer used even before this CL. This CL stops using the special
code path for malloc, because there is no place along that path where we
could conditionally insert the TSAN synchronization. This CL removes
the support for the special code path for both functions.
Instead, cgo now automatically generates the malloc function as though
it were referenced as C.malloc. We need to automatically generate it
even if C.malloc is not called, even if malloc and size_t are not
declared, to support cgo-provided functions like C.CString.
Change-Id: I829854ec0787a80f33fa0a8a0dc2ee1d617830e2
Reviewed-on: https://go-review.googlesource.com/23260
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Before, those C files might have been intended for the Plan 9 C compiler,
but that option was removed in Go 1.5. We can simplify the maintenance
of cgo packages now if we assume C files (and C++ and M and SWIG files)
should only be considered when cgo is enabled.
Also remove newly unnecessary build tags in runtime/cgo's C files.
Fixes#14123
Change-Id: Ia5a7fe62b9469965aa7c3547fe43c6c9292b8205
Reviewed-on: https://go-review.googlesource.com/19613
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This is a subset of https://golang.org/cl/20022 with only the copyright
header lines, so the next CL will be smaller and more reviewable.
Go policy has been single space after periods in comments for some time.
The copyright header template at:
https://golang.org/doc/contribute.html#copyright
also uses a single space.
Make them all consistent.
Change-Id: Icc26c6b8495c3820da6b171ca96a74701b4a01b0
Reviewed-on: https://go-review.googlesource.com/20111
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This makes "CGO_ENABLED=0 go list runtime/cgo" work,
which fixes the current cmd/go test failure.
Change-Id: Ia55ce3ba1dbb09f618ae5f4c8547722670360f59
Reviewed-on: https://go-review.googlesource.com/19001
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Bryan C. Mills
Ian Lance Taylor
Russ Cox
Brad Fitzpatrick