The x86_64_lam_qemu buildbots started failing
(https://lab.llvm.org/buildbot/#/builders/139/builds/5462/steps/2/logs/stdio).
Based on the logs, it appears the HWASan check is correct but it did not
match the stderr/stdout output. This patch attempts to fix the issue by
flushing stderr/stdout as appropriate.
Compiling with `-fxray-shared` requires position-independent code
(introduced in #113548).
Some tests do not explicitly specify this, thus falling back to the
compiler default.
If, for example, Clang is compiled with
`-DCLANG_DEFAULT_PIE_ON_LINUX=OFF`, these checks fail.
This patch addresses this issue in two tests:
- Removing a check in `xray-shared.cpp` that only tests default PIC
behavior
- Adding `-fPIC` explicitly in `clang-xray-shared.cpp`
This reverts commit 97fb21ac1d.
Due to issue brought up in #112780
> Unfortunately this breaks the build on our (automerger) bots, which
have -mmacosx-version-min=10.13 and also
-Werror=unguarded-availability-new . I was thinking about patching it
via wrapping in __builtin_available check (which I believe is the right
one to use, as it should match the -mmacosx-version-min ) - but can't
actually think of a quick fix, due to interceptors being defined via C
macros.
>
llvm-project/compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp:475:21:
error: 'aligned_alloc' is only available on macOS 10.15 or newer
[-Werror,-Wunguarded-availability-new] 475 | INTERCEPTOR(void *,
aligned_alloc, SIZE_T alignment, SIZE_T size) {
Include `cstdlib` which was originally included transitively but the
changes to `vector` in libcpp breaks new builds due to missing cstdlib
header for `abort()` function call.
Add explicit symbol visibility macros to InstrProfData.inc
Annotating these symbols will fix missing symbols for InstrProfTest when
using shared library builds on windows with explicit visibility macros
enabled.
Add a empty fallback definition for LLVM_ABI macro so the code works in
compiler-rt.
This is part of the work to enable LLVM_BUILD_LLVM_DYLIB and plugins on
window.
```
llvm\lld-link : error : undefined symbol: public: void ValueProfData::deserializeTo(InstrProfRecord&, InstrProfSymtab*)
>>> referenced by unittests\ProfileData\InstrProfTest.cpp:1372 void ValueProfileReadWriteTest_value_prof_data_read_write_Test::TestBody()
```
# What
This PR renames the newly-introduced llvm attribute
`sanitize_realtime_unsafe` to `sanitize_realtime_blocking`. Likewise,
sibling variables such as `SanitizeRealtimeUnsafe` are renamed to
`SanitizeRealtimeBlocking` respectively. There are no other functional
changes.
# Why?
- There are a number of problems that can cause a function to be
real-time "unsafe",
- we wish to communicate what problems rtsan detects and *why* they're
unsafe, and
- a generic "unsafe" attribute is, in our opinion, too broad a net -
which may lead to future implementations that need extra contextual
information passed through them in order to communicate meaningful
reasons to users.
- We want to avoid this situation and make the runtime library boundary
API/ABI as simple as possible, and
- we believe that restricting the scope of attributes to names like
`sanitize_realtime_blocking` is an effective means of doing so.
We also feel that the symmetry between `[[clang::blocking]]` and
`sanitize_realtime_blocking` is easier to follow as a developer.
# Concerns
- I'm aware that the LLVM attribute `sanitize_realtime_unsafe` has been
part of the tree for a few weeks now (introduced here:
https://github.com/llvm/llvm-project/pull/106754). Given that it hasn't
been released in version 20 yet, am I correct in considering this to not
be a breaking change?
This fixes remaining issues in my previous PR #90959.
Changes:
- Removed dependency on LLVM header in `xray_interface.cpp`
- Fixed XRay patching for some targets due to missing changes in
architecture-specific patching functions
- Addressed some remaining compiler warnings that I missed in the
previous patch
- Formatting
I have tested these changes on `x86_64` (natively), as well as
`ppc64le`, `aarch64` and `arm32` (cross-compiled and emulated using
qemu).
**Original description:**
This PR introduces shared library (DSO) support for XRay based on a
revised version of the implementation outlined in [this
RFC](https://discourse.llvm.org/t/rfc-upstreaming-dso-instrumentation-support-for-xray/73000).
The feature enables the patching and handling of events from DSOs,
supporting both libraries linked at startup or explicitly loaded, e.g.
via `dlopen`.
This patch adds the following:
- The `-fxray-shared` flag to enable the feature (turned off by default)
- A small runtime library that is linked into every instrumented DSO,
providing position-independent trampolines and code to register with the
main XRay runtime
- Changes to the XRay runtime to support management and patching of
multiple objects
These changes are fully backward compatible, i.e. running without
instrumented DSOs will produce identical traces (in terms of recorded
function IDs) to the previous implementation.
Due to my limited ability to test on other architectures, this feature
is only implemented and tested with x86_64. Extending support to other
architectures is fairly straightforward, requiring only a
position-independent implementation of the architecture-specific
trampoline implementation (see
`compiler-rt/lib/xray/xray_trampoline_x86_64.S` for reference).
This patch does not include any functionality to resolve function IDs
from DSOs for the provided logging/tracing modes. These modes still work
and will record calls from DSOs, but symbol resolution for these
functions in not available. Getting this to work properly requires
recording information about the loaded DSOs and should IMO be discussed
in a separate RFC, as there are mulitple feasible approaches.
---------
Co-authored-by: Sebastian Kreutzer <sebastian.kreutzer@tu-darmstadt.de>
I am currently trying to test the LLVM runtimes (including compiler-rt)
against an installed LLVM tree rather than a build tree (since that is
no longer available). Currently, the runtimes build of compiler-rt assumes
that LLVM_BINARY_DIR is writable since it uses configure_file() to write
there during the CMake configure stage. Instead, generate this file inside
CMAKE_CURRENT_BINARY_DIR, which will match LLVM_BINARY_DIR when invoked
from llvm/runtimes/CMakeLists.txt.
I also needed to make a minor change to the hwasan tests: hwasan_symbolize
was previously found in the LLVM_BINARY_DIR, but since it is generated as
part of the compiler-rt build it is now inside the CMake build directory
instead. I fixed this by passing the output directory to lit as
config.compiler_rt_bindir and using llvm_config.add_tool_substitutions().
For testing that we no longer write to the LLVM install directory as
part of testing or configuration, I created a read-only bind mount and
configured the runtimes builds as follows:
```
$ sudo mount --bind --read-only ~/llvm-install /tmp/upstream-llvm-readonly
$ cmake -DCMAKE_BUILD_TYPE=Debug \
-DCMAKE_C_COMPILER=/tmp/upstream-llvm-readonly/bin/clang \
-DCMAKE_CXX_COMPILER=/tmp/upstream-llvm-readonly/bin/clang++ \
-DLLVM_INCLUDE_TESTS=TRUE -DLLVM_ENABLE_ASSERTIONS=TRUE \
-DCOMPILER_RT_INCLUDE_TESTS=TRUE -DCOMPILER_RT_DEBUG=OFF \
-DLLVM_ENABLE_RUNTIMES=compiler-rt \
-DLLVM_BINARY_DIR=/tmp/upstream-llvm-readonly \
-G Ninja -S ~/upstream-llvm-project/runtimes \
-B ~/upstream-llvm-project/runtimes/cmake-build-debug-llvm-git
```
Reviewed By: ldionne
Pull Request: https://github.com/llvm/llvm-project/pull/86209
Some platforms (e.g. 64-bit CHERI) have stronger alignment requirements
on values returned from allocators. For all other platforms this does
not result in any functional change.
Reviewed By: cjappl, vitalybuka
Pull Request: https://github.com/llvm/llvm-project/pull/84440
The use of CLANG_NO_DEFAULT_CONFIG in the tests was added because some
Linux distributions had a global default config file, that added flags
relating to hardening, which interfere with the sanitizer tests. By
setting CLANG_NO_DEFAULT_CONFIG, the global default config files that
are found are ignored, and the sanitizers get the expected default
compiler behaviour.
(This was https://github.com/llvm/llvm-project/issues/60394, which was
fixed in 8ab762557fb057af1a3015211ee116a975027e78.)
However, some toolchains may rely on default config files for mandatory
parts required for functioning at all - setting things like sysroots,
-rtlib, -unwindlib, -stdlib, -fuse-ld etc. In such a case we can't
forcibly disable any default config, because it will break the otherwise
working toolchain.
Add a test for whether the compiler works while passing
--no-default-config to it. If the option is accepted and the toolchain
still works while that is set, set CLANG_NO_DEFAULT_CONFIG while running
tests.
(This adds a little bit of inconsistency, as we're testing for the
command line option, while using the environment variable. However doing
compile testing with an environment variable isn't quite as easily
doable, and passing an extra command line flag to all compile commands
while testing, is a bit clumsy - therefore this inconsistency.)
Some of the profile test files fail if they have CRLF newlines;
add a .gitattributes file that forces them to be checked out
with LF newlines, regarless of the user Git configuration.
According to the Arm Architecture Reference Manual for A-profile
architecture you can't have one feature without having the other:
ID_AA64ZFR0_EL1.AES, bits [7:4]
> FEAT_SVE_AES implements the functionality identified by the value
0b0001.
> FEAT_SVE_PMULL128 implements the functionality identified by the value
0b0010.
> The permitted values are 0b0000 and 0b0010.
(The following was removed from the latest release of the specification,
but it appears to be a mistake that was not intended to relax the
architecture constraints. The discrepancy has been reported)
ID_AA64ISAR0_EL1.AES, bits [7:4]
> FEAT_AES implements the functionality identified by the value 0b0001.
> FEAT_PMULL implements the functionality identified by the value
0b0010.
> From Armv8, the permitted values are 0b0000 and 0b0010.
Approved in ACLE as https://github.com/ARM-software/acle/pull/352
If we split these features in the compiler (see relevant pull request
https://github.com/llvm/llvm-project/pull/109299), we would only be able
to hand-write a 'memtag2' version using inline assembly since the
compiler cannot generate the instructions that become available with
FEAT_MTE2. However these instructions only work at Exception Level 1, so
they would be unusable since FMV is a user space facility. I am
therefore unifying them.
Approved in ACLE as https://github.com/ARM-software/acle/pull/351
This parameter seems unintentional here; we're trying to grep
the input on stdin, from the earlier stage in the pipeline.
Since a recent update on Github Actions runners, the previous
form (grepping a file, while piping in data on stdin) would fail
running the test, with the test runner Python script throwing
an exception when evaluating it:
File "D:\a\llvm-mingw\llvm-mingw\llvm-project\llvm\utils\lit\lit\TestRunner.py", line 935, in _executeShCmd
out = procs[i].stdout.read()
^^^^^^^^^^^^^^^^^^^^^^
File "C:\hostedtoolcache\windows\Python\3.12.7\x64\Lib\encodings\cp1252.py", line 23, in decode
return codecs.charmap_decode(input,self.errors,decoding_table)[0]
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: a bytes-like object is required, not 'NoneType'
For such threads we have no registers, so no exact
stack range, and no guaranties that stack is mapped
at all.
To avoid crashes on unmapped memory,
`MemCpyAccessible` copies intersting range into
temporarily buffer, and we search for pointers there.
The instruction is present in some library in the 24H2 update for
Windows 11:
==8508==interception_win: unhandled instruction at 0x7ff83e193a40: 44 0f
b6 1a 4c 8b d2 48
This could be generalized, but getting all the ModR/M byte combinations
right is tricky. Many other classes of instructions handled in this file
could use some generalization too.
For posix implementation is similar to
`IsAccessibleMemoryRange`, using `pipe`.
We need this because we can't rely on non-atomic
`IsAccessibleMemoryRange` + `memcpy`, as the
protection or mapping may change and we may
crash.
The comment stated that it's slow, but likely it's a deadlock,
as write can be blocked.
Also we can't be sure that `page_size * 10` is appropriate size.
Still most likely this is NFC, as the max `size` we use is 32,
and should fit in any buffer.
This PR registers the writeout and reset functions for `gcov` for all
modules in the PGO runtime, instead of registering them
using global constructors in each module. The change is made for AIX
only, but the same mechanism works on Linux on Power.
When registering such functions using global constructors in each module
without `-ffunction-sections`, the AIX linker cannot garbage collect
unused undefined symbols, because such symbols are grouped in the same
section as the `__sinit` symbol. Keeping such undefined symbols causes
link errors (see test case
https://github.com/llvm/llvm-project/pull/108570/files#diff-500a7e1ba871e1b6b61b523700d5e30987900002add306e1b5e4972cf6d5a4f1R1
for this scenario). This PR implements the initialization in the
runtime, hence avoiding introducing `__sinit` into each module.
The implementation adds a new global variable `__llvm_covinit_functions`
to each module. This new global variable contains the function pointers
to the `Writeout` and `Reset` functions. `__llvm_covinit_functions`'s
section is the named section `__llvm_covinit`. The linker will aggregate
all the `__llvm_covinit` sections from each module
to form one single named section in the final binary. The pair of
functions
```
const __llvm_gcov_init_func_struct *__llvm_profile_begin_covinit();
const __llvm_gcov_init_func_struct *__llvm_profile_end_covinit();
```
are implemented to return the start and end address of this named
section in the final binary, and they are used in function
```
__llvm_profile_gcov_initialize()
```
(which is a constructor function in the runtime) so the runtime knows
the addresses of all the `Writeout` and `Reset` functions from all the
modules.
One noticeable implementation detail relevant to AIX is that to preserve
the `__llvm_covinit` from the linker's garbage collection, a `.ref`
pseudo instruction is inserted into them, referring to the section that
contains the `__llvm_gcov_ctr` variables, which are used in the
instrumented code. The `__llvm_gcov_ctr` variables did not belong to
named sections before, but this PR added them to the
`__llvm_gcov_ctr_section` named section, so we can add a `.ref` pseudo
instruction that refers to them in the `__llvm_covinit` section.
