Soft-transition the removal of setting ZXTEST_USE_STREAMABLE_MACROS, by
only setting the macro if not already defined. A future PR will remove
setting the macro entirely in harness.h.
While fetching amounts of bits used to correctly display ubsan value
reinterpret_cast was used, however as noted by Jakub Jelínek in
https://github.com/llvm/llvm-project/pull/96240 discussion it might
cause issues due to potentially unaligned memory access. The patch
addresses this problem.
Co-authored-by: Vladislav Aranov <vladislav.aranov@ericsson.com>
Our platform has some constraints that allow us to make assumptions that
aren't generally applicable to other platforms. We keep an entirely separate
.s file for the routines.
TYSan CMake build follows patterns used by other sanitizers, but there's
also a number of issues, like referring to undefined variables, which
breaks the build in some cases (such as cross-compiling). This change
addresses the issues.
Linking this runtime requires C++ ABI, which breaks -nostdlib++ builds.
However, UBSAN C++ runtime is only needed for CFI and VPTR checks.
Unblocks #120370.
When ntdll was added to the list of of "interesting DLLs" list (in
d58230b9dc), the intention was not to
intercept the "mini CRT" functions it exports. OverrideFunction would
only intercept the *first* function it found when searching the list of
DLLs, and ntdll was put last in that list.
However, after 42cdfbcf3e,
OverrideFunction intercepts *all* matching functions in those DLLs. As
a side-effect, the runtime would now intercept functions like memset
etc. also in ntdll.
This causes a problem when ntdll-internal functions like
RtlDispatchException call the intercepted memset, which tries to
inspect uncommitted shadow memory, raising an exception, and getting
stuck in that loop until the stack overflows.
Since we never intended to intercept ntdll's memset etc., the simplest
fix seems to be to actively ignore ntdll when intercepting those
functions.
Fixes#114793
This patch works around:
compiler-rt/lib/tysan/../sanitizer_common/sanitizer_platform_limits_posix.h:604:3:
error: anonymous structs are a GNU extension
[-Werror,-Wgnu-anonymous-struct]
This patch introduces the runtime components for type sanitizer: a
sanitizer for type-based aliasing violations.
It is based on Hal Finkel's https://reviews.llvm.org/D32197.
C/C++ have type-based aliasing rules, and LLVM's optimizer can exploit
these given TBAA metadata added by Clang. Roughly, a pointer of given
type cannot be used to access an object of a different type (with, of
course, certain exceptions). Unfortunately, there's a lot of code in the
wild that violates these rules (e.g. for type punning), and such code
often must be built with -fno-strict-aliasing. Performance is often
sacrificed as a result. Part of the problem is the difficulty of finding
TBAA violations. Hopefully, this sanitizer will help.
For each TBAA type-access descriptor, encoded in LLVM's IR using
metadata, the corresponding instrumentation pass generates descriptor
tables. Thus, for each type (and access descriptor), we have a unique
pointer representation. Excepting anonymous-namespace types, these
tables are comdat, so the pointer values should be unique across the
program. The descriptors refer to other descriptors to form a type
aliasing tree (just like LLVM's TBAA metadata does). The instrumentation
handles the "fast path" (where the types match exactly and no
partial-overlaps are detected), and defers to the runtime to handle all
of the more-complicated cases. The runtime, of course, is also
responsible for reporting errors when those are detected.
The runtime uses essentially the same shadow memory region as tsan, and
we use 8 bytes of shadow memory, the size of the pointer to the type
descriptor, for every byte of accessed data in the program. The value 0
is used to represent an unknown type. The value -1 is used to represent
an interior byte (a byte that is part of a type, but not the first
byte). The instrumentation first checks for an exact match between the
type of the current access and the type for that address recorded in the
shadow memory. If it matches, it then checks the shadow for the
remainder of the bytes in the type to make sure that they're all -1. If
not, we call the runtime. If the exact match fails, we next check if the
value is 0 (i.e. unknown). If it is, then we check the shadow for the
remainder of the byes in the type (to make sure they're all 0). If
they're not, we call the runtime. We then set the shadow for the access
address and set the shadow for the remaining bytes in the type to -1
(i.e. marking them as interior bytes). If the type indicated by the
shadow memory for the access address is neither an exact match nor 0, we
call the runtime.
The instrumentation pass inserts calls to the memset intrinsic to set
the memory updated by memset, memcpy, and memmove, as well as
allocas/byval (and for lifetime.start/end) to reset the shadow memory to
reflect that the type is now unknown. The runtime intercepts memset,
memcpy, etc. to perform the same function for the library calls.
The runtime essentially repeats these checks, but uses the full TBAA
algorithm, just as the compiler does, to determine when two types are
permitted to alias. In a situation where access overlap has occurred and
aliasing is not permitted, an error is generated.
As a note, this implementation does not use the compressed shadow-memory
scheme discussed previously
(http://lists.llvm.org/pipermail/llvm-dev/2017-April/111766.html). That
scheme would not handle the struct-path (i.e. structure offset)
information that our TBAA represents. I expect we'll want to further
work on compressing the shadow-memory representation, but I think it
makes sense to do that as follow-up work.
This includes build fixes for Linux from Mingjie Xu.
Depends on #76260 (Clang support), #76259 (LLVM support)
PR: https://github.com/llvm/llvm-project/pull/76261
Avoid issues caused by `.subsections_via_symbols` directive, by using
numbered labels instead of named labels for the branch locations.
This reverts commit 4032ce3413.
Support platform-specific mangling to avoid the compiler emitting a call
to a function that is mangled differently than the definition in the
runtime library.
According to the conversation
[here](https://github.com/llvm/llvm-project/pull/119414#issuecomment-2536495859),
some platforms don't enable `__arm_cpu_features` with a global
constructor, but rather do so lazily when called from the FMV resolver.
PR #119414 removed the CMake guard to check to see if the targetted
platform is baremetal or supports sys/auxv. Without this check, the
routines rely on `__arm_cpu_features` being initialised when they may
not be, depending on the platform.
This PR simply avoids building the SME routines for those platforms for
now.
fd_set is defined by `sys/select.h`. On musl, this header is not
transitively included by the other headers.
Failure message:
```
compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp:761:37: error: unknown type name 'fd_set'; did you mean 'fd_t'?
761 | INTERCEPTOR(int, pselect, int nfds, fd_set *readfds, fd_set *writefds,
| ^~~~~~
| fd_t
```
When #92921 added the `__arm_get_current_vg` functionality, it used the
FMV feature bits mechanism rather than the mechanism that was previously
added for SME which called `getauxval` on Linux platforms or
`__aarch64_sme_accessible` required for baremetal libraries. It is
better to always use `__aarch64_cpu_features`.
For baremetal we still need to rely on `__arm_sme_accessible` to
initialise the struct.
