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Revision tags: llvmorg-18.1.8, llvmorg-18.1.7, llvmorg-18.1.6, llvmorg-18.1.5, llvmorg-18.1.4, llvmorg-18.1.3, llvmorg-18.1.2, llvmorg-18.1.1, llvmorg-18.1.0, llvmorg-18.1.0-rc4, llvmorg-18.1.0-rc3, llvmorg-18.1.0-rc2, llvmorg-18.1.0-rc1, llvmorg-19-init, llvmorg-17.0.6, llvmorg-17.0.5, llvmorg-17.0.4, llvmorg-17.0.3, llvmorg-17.0.2, llvmorg-17.0.1, llvmorg-17.0.0, llvmorg-17.0.0-rc4, llvmorg-17.0.0-rc3, llvmorg-17.0.0-rc2, llvmorg-17.0.0-rc1, llvmorg-18-init, llvmorg-16.0.6, llvmorg-16.0.5, llvmorg-16.0.4, llvmorg-16.0.3, llvmorg-16.0.2, llvmorg-16.0.1, llvmorg-16.0.0, llvmorg-16.0.0-rc4, llvmorg-16.0.0-rc3, llvmorg-16.0.0-rc2, llvmorg-16.0.0-rc1, llvmorg-17-init, llvmorg-15.0.7 |
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b076e515 |
| 02-Dec-2022 |
Roy Sundahl <rsundahl@apple.com> |
[ubsan][test] Be more specific than "error:" with implicit-check-not
The string "error:" is too general and reports false positive from system
messages that can occur on stderr when using network de
[ubsan][test] Be more specific than "error:" with implicit-check-not
The string "error:" is too general and reports false positive from system
messages that can occur on stderr when using network devices for testing.
The string "runtime error:" is sufficiently unique for these connection
errors to pass through w/o a false positive.
rdar://100564373
Reviewed By: thetruestblue
Differential Revision: https://reviews.llvm.org/D139230
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Revision tags: llvmorg-15.0.6, llvmorg-15.0.5, llvmorg-15.0.4, llvmorg-15.0.3, working, llvmorg-15.0.2, llvmorg-15.0.1, llvmorg-15.0.0, llvmorg-15.0.0-rc3, llvmorg-15.0.0-rc2, llvmorg-15.0.0-rc1, llvmorg-16-init, llvmorg-14.0.6, llvmorg-14.0.5, llvmorg-14.0.4, llvmorg-14.0.3, llvmorg-14.0.2, llvmorg-14.0.1, llvmorg-14.0.0, llvmorg-14.0.0-rc4, llvmorg-14.0.0-rc3, llvmorg-14.0.0-rc2, llvmorg-14.0.0-rc1, llvmorg-15-init, llvmorg-13.0.1, llvmorg-13.0.1-rc3, llvmorg-13.0.1-rc2, llvmorg-13.0.1-rc1, llvmorg-13.0.0, llvmorg-13.0.0-rc4, llvmorg-13.0.0-rc3, llvmorg-13.0.0-rc2, llvmorg-13.0.0-rc1, llvmorg-14-init, llvmorg-12.0.1, llvmorg-12.0.1-rc4, llvmorg-12.0.1-rc3, llvmorg-12.0.1-rc2, llvmorg-12.0.1-rc1, llvmorg-12.0.0, llvmorg-12.0.0-rc5, llvmorg-12.0.0-rc4, llvmorg-12.0.0-rc3, llvmorg-12.0.0-rc2, llvmorg-11.1.0, llvmorg-11.1.0-rc3, llvmorg-12.0.0-rc1, llvmorg-13-init, llvmorg-11.1.0-rc2, llvmorg-11.1.0-rc1, llvmorg-11.0.1, llvmorg-11.0.1-rc2, llvmorg-11.0.1-rc1, llvmorg-11.0.0, llvmorg-11.0.0-rc6, llvmorg-11.0.0-rc5, llvmorg-11.0.0-rc4, llvmorg-11.0.0-rc3, llvmorg-11.0.0-rc2, llvmorg-11.0.0-rc1, llvmorg-12-init, llvmorg-10.0.1, llvmorg-10.0.1-rc4, llvmorg-10.0.1-rc3, llvmorg-10.0.1-rc2, llvmorg-10.0.1-rc1, llvmorg-10.0.0, llvmorg-10.0.0-rc6, llvmorg-10.0.0-rc5, llvmorg-10.0.0-rc4, llvmorg-10.0.0-rc3, llvmorg-10.0.0-rc2, llvmorg-10.0.0-rc1, llvmorg-11-init, llvmorg-9.0.1, llvmorg-9.0.1-rc3, llvmorg-9.0.1-rc2, llvmorg-9.0.1-rc1 |
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| #
536b0ee4 |
| 10-Oct-2019 |
Roman Lebedev <lebedev.ri@gmail.com> |
[UBSan][clang][compiler-rt] Applying non-zero offset to nullptr is undefined behaviour
Summary:
Quote from http://eel.is/c++draft/expr.add#4:
```
4 When an expression J that has integral type is
[UBSan][clang][compiler-rt] Applying non-zero offset to nullptr is undefined behaviour
Summary:
Quote from http://eel.is/c++draft/expr.add#4:
```
4 When an expression J that has integral type is added to or subtracted
from an expression P of pointer type, the result has the type of P.
(4.1) If P evaluates to a null pointer value and J evaluates to 0,
the result is a null pointer value.
(4.2) Otherwise, if P points to an array element i of an array object x with n
elements ([dcl.array]), the expressions P + J and J + P
(where J has the value j) point to the (possibly-hypothetical) array
element i+j of x if 0≤i+j≤n and the expression P - J points to the
(possibly-hypothetical) array element i−j of x if 0≤i−j≤n.
(4.3) Otherwise, the behavior is undefined.
```
Therefore, as per the standard, applying non-zero offset to `nullptr`
(or making non-`nullptr` a `nullptr`, by subtracting pointer's integral value
from the pointer itself) is undefined behavior. (*if* `nullptr` is not defined,
i.e. e.g. `-fno-delete-null-pointer-checks` was *not* specified.)
To make things more fun, in C (6.5.6p8), applying *any* offset to null pointer
is undefined, although Clang front-end pessimizes the code by not lowering
that info, so this UB is "harmless".
Since rL369789 (D66608 `[InstCombine] icmp eq/ne (gep inbounds P, Idx..), null -> icmp eq/ne P, null`)
LLVM middle-end uses those guarantees for transformations.
If the source contains such UB's, said code may now be miscompiled.
Such miscompilations were already observed:
* https://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20190826/687838.html
* https://github.com/google/filament/pull/1566
Surprisingly, UBSan does not catch those issues
... until now. This diff teaches UBSan about these UB's.
`getelementpointer inbounds` is a pretty frequent instruction,
so this does have a measurable impact on performance;
I've addressed most of the obvious missing folds (and thus decreased the performance impact by ~5%),
and then re-performed some performance measurements using my [[ https://github.com/darktable-org/rawspeed | RawSpeed ]] benchmark:
(all measurements done with LLVM ToT, the sanitizer never fired.)
* no sanitization vs. existing check: average `+21.62%` slowdown
* existing check vs. check after this patch: average `22.04%` slowdown
* no sanitization vs. this patch: average `48.42%` slowdown
Reviewers: vsk, filcab, rsmith, aaron.ballman, vitalybuka, rjmccall, #sanitizers
Reviewed By: rsmith
Subscribers: kristof.beyls, nickdesaulniers, nikic, ychen, dtzWill, xbolva00, dberris, arphaman, rupprecht, reames, regehr, llvm-commits, cfe-commits
Tags: #clang, #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D67122
llvm-svn: 374293
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Revision tags: llvmorg-9.0.0, llvmorg-9.0.0-rc6, llvmorg-9.0.0-rc5, llvmorg-9.0.0-rc4, llvmorg-9.0.0-rc3, llvmorg-9.0.0-rc2, llvmorg-9.0.0-rc1, llvmorg-10-init, llvmorg-8.0.1, llvmorg-8.0.1-rc4, llvmorg-8.0.1-rc3, llvmorg-8.0.1-rc2, llvmorg-8.0.1-rc1, llvmorg-8.0.0, llvmorg-8.0.0-rc5, llvmorg-8.0.0-rc4, llvmorg-8.0.0-rc3, llvmorg-7.1.0, llvmorg-7.1.0-rc1, llvmorg-8.0.0-rc2, llvmorg-8.0.0-rc1, llvmorg-7.0.1, llvmorg-7.0.1-rc3, llvmorg-7.0.1-rc2, llvmorg-7.0.1-rc1, llvmorg-7.0.0, llvmorg-7.0.0-rc3 |
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| #
4218a006 |
| 03-Sep-2018 |
Dan Liew <dan@su-root.co.uk> |
[UBSan] Add missing `%run` prefixes to Pointer tests.
Summary: rdar://problem/41126835
Reviewers: vsk, kubamracek
Subscribers: #sanitizers, llvm-commits
Differential Revision: https://reviews.llv
[UBSan] Add missing `%run` prefixes to Pointer tests.
Summary: rdar://problem/41126835
Reviewers: vsk, kubamracek
Subscribers: #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D51271
llvm-svn: 341298
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Revision tags: llvmorg-7.0.0-rc2, llvmorg-7.0.0-rc1, llvmorg-6.0.1, llvmorg-6.0.1-rc3, llvmorg-6.0.1-rc2, llvmorg-6.0.1-rc1, llvmorg-5.0.2, llvmorg-5.0.2-rc2, llvmorg-5.0.2-rc1, llvmorg-6.0.0, llvmorg-6.0.0-rc3, llvmorg-6.0.0-rc2, llvmorg-6.0.0-rc1, llvmorg-5.0.1, llvmorg-5.0.1-rc3, llvmorg-5.0.1-rc2, llvmorg-5.0.1-rc1, llvmorg-5.0.0, llvmorg-5.0.0-rc5, llvmorg-5.0.0-rc4, llvmorg-5.0.0-rc3, llvmorg-5.0.0-rc2, llvmorg-5.0.0-rc1, llvmorg-4.0.1, llvmorg-4.0.1-rc3 |
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| #
41dfc4f1 |
| 01-Jun-2017 |
Vedant Kumar <vsk@apple.com> |
[ubsan] Runtime support for pointer overflow checking
Patch by John Regehr and Will Dietz!
Differential Revision: https://reviews.llvm.org/D20323
llvm-svn: 304461
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