[all-commits] [llvm/llvm-project] 474d35: [safestack] Various Solaris fixes (#99290)

[Rainer Orth via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 474d35f238d46010d12485734e62de91cb469404
      https://github.com/llvm/llvm-project/commit/474d35f238d46010d12485734e62de91cb469404
  Author: Rainer Orth <ro at gcc.gnu.org>
  Date:   2024-07-18 (Thu, 18 Jul 2024)

  Changed paths:
    M compiler-rt/cmake/Modules/AllSupportedArchDefs.cmake
    M compiler-rt/lib/safestack/safestack.cpp
    M compiler-rt/lib/safestack/safestack_platform.h
    M compiler-rt/test/safestack/lit.cfg.py

  Log Message:
  -----------
  [safestack] Various Solaris fixes (#99290)

Even with the `-u __safestack_init` link order fixed on Solaris, there
are still several safestack test issues left:

- While 540fd42c755f20f7b79c6c79493ec36d8cb9b3d3 enabled safestack on
Solaris in the driver unconditionally, it ignored that Solaris also
exists on SPARC and forgot to enable SPARC support for the runtime lib.
This patch fixes that.

- The tests fail to link with undefined references to
`__sanitizer_internal_memset` etc in `safestack.cpp.o` and
`interception_linux.cpp.o`. These are from indirectly including
`sanitizer_redefine_builtins.h`. Instead of using the implementations
from `sanitizer_common` as was done in [[safestack] Various Solaris
fixes](https://github.com/llvm/llvm-project/pull/98469), this patch
disables the interception as discussed in [Revert "[safestack] Various
Solaris fixes"](https://github.com/llvm/llvm-project/pull/98541). A
similar issue affects 32-bit Linux/sparc where compiling `safestack.cpp`
with `-ftrivial-auto-var-init=pattern` causes the compiler to generate
calls to `memset` to initialize a `pthread_attr_t` which is larger than
can be handled inline. This is avoided by defining
`SANITIZER_COMMON_NO_REDEFINE_BUILTINS` in `safestack.cpp` and also
adding definitions of the interceptors that just forward to `libc` for
the benefit of `interception_linux.cpp`.

- The `pthread*.c` tests `FAIL` with

``` safestack CHECK failed:
/vol/llvm/src/llvm-project/local/compiler-rt/lib/safestack/safestack.cpp:227
size ```

The problem is that `pthread_attr_init` initializes the `stacksize`
attribute to 0, signifying the default. Unless explicitly overridded, it
stays that way. I think this is allowed by XPG7. Since safestack cannot
deal with this, I set `size` to the defaults documented in
`pthread_create(3C)`. Unfortunately, there's no macro for those values
outside of private `libc` headers.

- The Solaris `syscall` interface isn't stable. This is not just a
theoretical concern, but the syscalls have changed incompatibly several
times in the past. Therefore this patch switches the implementations of
`TgKill` (where `SYS_lwp_kill` doesn't exist on Solaris 11.4 anyway),
`Mmap`, `Munmap`, and `Mprotect` to the same `_REAL*` solution already
used in `sanitizer_solaris.cpp`.

With those changes, safestack compiles and all tests `PASS`, so the
tests are re-enabled for good.

Tested on `amd64-pc-solaris2.11`, `sparcv9-sun-solaris2.11`,
`x86_64-pc-linux-gnu`, and `sparc64-unknown-linux-gnu`.



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