This removes an abuse of ELF linker behaviors while keeping Mach-O/COFF linker
behaviors unchanged.
ELF: when module_ctor is in a comdat, this patch removes reliance on a linker
abuse (an SHT_INIT_ARRAY in a section group retains the whole group) by using
SHF_GNU_RETAIN. No linker behavior difference when module_ctor is not in a comdat.
Mach-O: module_ctor gets `N_NO_DEAD_STRIP`. No linker behavior difference
because module_ctor is already referenced by a `S_MOD_INIT_FUNC_POINTERS`
section (GC root).
PE/COFF: no-op. SanitizerCoverage already appends module_ctor to `llvm.used`.
Other sanitizers: llvm.used for local linkage is not implemented in
`TargetLoweringObjectFileCOFF::emitLinkerDirectives` (once implemented or
switched to a non-local linkage, COFF can use module_ctor in comdat (i.e.
generalize ELF-specific rL301586)).
There is no object file size difference.
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D106246
Since d6de1e1a71406c75a4ea4d5a2fe84289f07ea3a1, no attributes is quivalent to
setting attribute to false.
This is a preliminary commit for https://reviews.llvm.org/D99080
On ELF targets, if a function has uwtable or personality, or does not have
nounwind (`needsUnwindTableEntry`), it marks that `.eh_frame` is needed in the module.
Then, a function gets `.eh_frame` if `needsUnwindTableEntry` or `-g[123]` is specified.
(i.e. If -g[123], every function gets `.eh_frame`.
This behavior is strange but that is the status quo on GCC and Clang.)
Let's take asan as an example. Other sanitizers are similar.
`asan.module_[cd]tor` has no attribute. `needsUnwindTableEntry` returns true,
so every function gets `.eh_frame` if `-g[123]` is specified.
This is the root cause that
`-fno-exceptions -fno-asynchronous-unwind-tables -g` produces .debug_frame
while
`-fno-exceptions -fno-asynchronous-unwind-tables -g -fsanitize=address` produces .eh_frame.
This patch
* sets the nounwind attribute on sanitizer module ctor/dtor.
* let Clang emit a module flag metadata "uwtable" for -fasynchronous-unwind-tables. If "uwtable" is set, sanitizer module ctor/dtor additionally get the uwtable attribute.
The "uwtable" mechanism is generic: synthesized functions not cloned/specialized
from existing ones should consider `Function::createWithDefaultAttr` instead of
`Function::create` if they want to get some default attributes which
have more of module semantics.
Other candidates: "frame-pointer" (https://github.com/ClangBuiltLinux/linux/issues/955https://github.com/ClangBuiltLinux/linux/issues/1238), dso_local, etc.
Differential Revision: https://reviews.llvm.org/D100251
This patch sets the default for llvm tests, with the exception of tests
under Reduce, because quite a few of them use 'FileCheck' as parameter
to a tool, and including a flag as that parameter would complicate
matters.
The rest of the patch undo-es the lit.local.cfg changes we progressively
introduced as temporary measure to avoid regressions under various
directories.
Differential Revision: https://reviews.llvm.org/D95111
As mentioned in D93793, there are quite a few places where unary `IRBuilder::CreateShuffleVector(X, Mask)` can be used
instead of `IRBuilder::CreateShuffleVector(X, Undef, Mask)`.
Let's update them.
Actually, it would have been more natural if the patches were made in this order:
(1) let them use unary CreateShuffleVector first
(2) update IRBuilder::CreateShuffleVector to use poison as a placeholder value (D93793)
The order is swapped, but in terms of correctness it is still fine.
Reviewed By: spatel
Differential Revision: https://reviews.llvm.org/D93923
D70365 allows us to make attributes default. This is a follow up to
actually make nosync, nofree and willreturn default. The approach we
chose, for now, is to opt-in to default attributes to avoid introducing
problems to target specific intrinsics. Intrinsics with default
attributes can be created using `DefaultAttrsIntrinsic` class.
This would be a problem if the entire instrumented function was a call
to
e.g. memcpy
Use FnPrologueEnd Instruction* instead of ActualFnStart BB*
Differential Revision: https://reviews.llvm.org/D86001
This allows us to add addtional instrumentation before the function start,
without splitting the first BB.
Differential Revision: https://reviews.llvm.org/D85985
Have the front-end use the `nounwind` attribute on atomic libcalls.
This prevents us from seeing `invoke __atomic_load` in MSAN, which
is problematic as it has no successor for instrumentation to be added.
Problems with instrumenting atomic_load when the call has no successor,
blocking compiler roll
This reverts commit 33d239513c881d8c11c60d5710c55cf56cc309a5.
MSan removes readnone/readonly and similar attributes from callees,
because after MSan instrumentation those attributes no longer apply.
This change removes the attributes from call sites, as well.
Failing to do this may cause DSE of paramTLS stores before calls to
readonly/readnone functions.
Differential Revision: https://reviews.llvm.org/D85259
Freeze always returns a defined value. This also prevents msan from
checking the input shadow, which happened because freeze wasn't
explicitly visited.
Differential Revision: https://reviews.llvm.org/D85040
These calls are neither intercepted by compiler-rt nor is libatomic.a
naturally instrumented.
This patch uses the existing libcall mechanism to detect a call
to atomic_load or atomic_store, and instruments them much like
the preexisting instrumentation for atomics.
Calls to _load are modified to have at least Acquire ordering, and
calls to _store at least Release ordering. Because this needs to be
converted at runtime, msan injects a LUT (implemented as a vector
with extractelement).
Differential Revision: https://reviews.llvm.org/D83337
Implement llvm.experimental.vector.{add,mul,or,and,...}.
An IR test is included but no C test for lack of good way to
get the compiler to emit these.
Differential Revision: https://reviews.llvm.org/D82920
Adds LLVM option to control eager checking under -msan-eager-checks.
This change depends on the noundef keyword to determining cases where it
it sound to check these shadows, and falls back to passing shadows
values by TLS.
Checking at call boundaries enforces undefined behavior rules with
passing uninitialized arguments by value.
Differential Revision: https://reviews.llvm.org/D81699
Summary: `nomerge` attribute was added at D78659. So, we can remove the EmptyAsm workaround in ASan the MSan and use this attribute.
Reviewers: vitalybuka
Reviewed By: vitalybuka
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D82322
Summary:
Normally, the Origin is passed over TLS, which seems like it introduces unnecessary overhead. It's in the (extremely) cold path though, so the only overhead is in code size.
But with eager-checks, calls to __msan_warning functions are extremely common, so this becomes a useful optimization.
This can save ~5% code size.
Reviewers: eugenis, vitalybuka
Reviewed By: eugenis, vitalybuka
Subscribers: hiraditya, #sanitizers, llvm-commits
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D81700
This is D77454, except for stores. All the infrastructure work was done
for loads, so the remaining changes necessary are relatively small.
Differential Revision: https://reviews.llvm.org/D79968
Summary:
This patch establishes memory layout and adds instrumentation. It does
not add runtime support and does not enable MSan, which will be done
separately.
Memory layout is based on PPC64, with the exception that XorMask
is not used - low and high memory addresses are chosen in a way that
applying AndMask to low and high memory produces non-overlapping
results.
VarArgHelper is based on AMD64. It might be tempting to share some
code between the two implementations, but we need to keep in mind that
all the ABI similarities are coincidental, and therefore any such
sharing might backfire.
copyRegSaveArea() indiscriminately copies the entire register save area
shadow, however, fragments thereof not filled by the corresponding
visitCallSite() invocation contain irrelevant data. Whether or not this
can lead to practical problems is unclear, hence a simple TODO comment.
Note that the behavior of the related copyOverflowArea() is correct: it
copies only the vararg-related fragment of the overflow area shadow.
VarArgHelper test is based on the AArch64 one.
s390x ABI requires that arguments are zero-extended to 64 bits. This is
particularly important for __msan_maybe_warning_*() and
__msan_maybe_store_origin_*() shadow and origin arguments, since non
zeroed upper parts thereof confuse these functions. Therefore, add ZExt
attribute to the corresponding parameters.
Add ZExt attribute checks to msan-basic.ll. Since with
-msan-instrumentation-with-call-threshold=0 instrumentation looks quite
different, introduce the new CHECK-CALLS check prefix.
Reviewers: eugenis, vitalybuka, uweigand, jonpa
Reviewed By: eugenis
Subscribers: kristof.beyls, hiraditya, danielkiss, llvm-commits, stefansf, Andreas-Krebbel
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D76624
Some IRBuilder methods that were originally defined on
IRBuilderBase do not respect custom IRBuilder inserters/folders,
because those were not accessible prior to D73835. Fix this by
making use of existing (and now accessible) IRBuilder methods,
which will handle inserters/folders correctly.
There are some changes in OpenMP and Instrumentation tests, where
bitcasts now get constant folded. I've also highlighted one
InstCombine test which now finishes in two rather than three
iterations, thanks to new instructions being inserted into the
worklist.
Differential Revision: https://reviews.llvm.org/D74787
Summary:
These instructions ignore parts of the input vectors which makes the
default MSan handling too strict and causes false positive reports.
Reviewers: vitalybuka, RKSimon, thakis
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73374
Summary:
MSan instrumentation adds stores and loads even to pure
readonly/writeonly functions. It is removing some of those attributes
from instrumented functions and call targets, but apparently not enough.
Remove writeonly, argmemonly and speculatable in addition to readonly /
readnone.
Reviewers: pcc, vitalybuka
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D69541
Summary:
If we insert them from function pass some analysis may be missing or invalid.
Fixes PR42877.
Reviewers: eugenis, leonardchan
Reviewed By: leonardchan
Subscribers: hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D68832
> llvm-svn: 374481
Signed-off-by: Vitaly Buka <vitalybuka@google.com>
llvm-svn: 374527
Summary:
If we insert them from function pass some analysis may be missing or invalid.
Fixes PR42877.
Reviewers: eugenis, leonardchan
Reviewed By: leonardchan
Subscribers: hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D68832
llvm-svn: 374481
