Commit Graph

10 Commits

Author SHA1 Message Date
Vedant Kumar 3cbce5d278 [docs] Clarify sanitizer flag behavior
PR32346 suggests that UBSan's docs about the -fsanitize,
-fno-sanitize-recover, and -fsanitize-trap options are not explicit
enough. Try to improve the wording.

llvm-svn: 298310
2017-03-20 21:40:58 +00:00
Vedant Kumar 42c17ec5ac [ubsan] Add a nullability sanitizer
Teach UBSan to detect when a value with the _Nonnull type annotation
assumes a null value. Call expressions, initializers, assignments, and
return statements are all checked.

Because _Nonnull does not affect IRGen, the new checks are disabled by
default. The new driver flags are:

  -fsanitize=nullability-arg      (_Nonnull violation in call)
  -fsanitize=nullability-assign   (_Nonnull violation in assignment)
  -fsanitize=nullability-return   (_Nonnull violation in return stmt)
  -fsanitize=nullability          (all of the above)

This patch builds on top of UBSan's existing support for detecting
violations of the nonnull attributes ('nonnull' and 'returns_nonnull'),
and relies on the compiler-rt support for those checks. Eventually we
will need to update the diagnostic messages in compiler-rt (there are
FIXME's for this, which will be addressed in a follow-up).

One point of note is that the nullability-return check is only allowed
to kick in if all arguments to the function satisfy their nullability
preconditions. This makes it necessary to emit some null checks in the
function body itself.

Testing: check-clang and check-ubsan. I also built some Apple ObjC
frameworks with an asserts-enabled compiler, and verified that we get
valid reports.

Differential Revision: https://reviews.llvm.org/D30762

llvm-svn: 297700
2017-03-14 01:56:34 +00:00
Nico Weber 614e60de1c UBSan docs: Explicitly mention that `-fsanitize=unsigned-integer-overflow` does not catch UB.
https://reviews.llvm.org/D27455

llvm-svn: 296387
2017-02-27 21:27:07 +00:00
Nick Lewycky d8d498657a Fix typo in documentation.
Since this is a header it will break links to this section.

llvm-svn: 281996
2016-09-20 18:37:25 +00:00
Filipe Cabecinhas ab731f7e86 [ubsan] Add -fsanitize-undefined-strip-path-components=N
Summary:
This option allows the user to control how much of the file name is
emitted by UBSan. Tuning this option allows one to save space in the
resulting binary, which is helpful for restricted execution
environments.

With a positive N, UBSan skips the first N path components.
With a negative N, UBSan only keeps the last N path components.

Reviewers: rsmith

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D19666

llvm-svn: 269309
2016-05-12 16:51:36 +00:00
George Burgess IV a17674b7cc [Docs] Fix indentation error introduced by r267447.
llvm-svn: 267501
2016-04-26 00:31:29 +00:00
George Burgess IV 58ebc66e98 [Docs] Clarify what the object-size sanitizer does.
Currently, the UBSan docs make it sound like the object-size sanitizer
will only detect out-of-bounds reads/writes. It also catches some
operations that don't necessarily access memory (invalid downcasts,
calls of methods on invalid pointers, ...). This patch adds a note
about this behavior in the docs.

llvm-svn: 267447
2016-04-25 19:21:45 +00:00
Alexey Samsonov 7f5b2d0ac8 [UBSan] Add documentation for runtime issue suppression.
llvm-svn: 259260
2016-01-29 23:07:14 +00:00
Alexey Samsonov b6761c2e1e [Docs] One more cleanup of -fsanitize= section.
Describe -fsanitize-blacklist flags in separate paragraphs, move
notes about importance of clang++ for vptr down to UBSan docs.

llvm-svn: 254798
2015-12-04 23:13:14 +00:00
Alexey Samsonov 778fc728ed Clang documentation for UBSan.
Summary:
Create a separate page describing UBSan tool, move the description of
fine-grained checks there, provide extra information about supported
platforms, symbolization etc. This text is compiled from four parts:

* Existing documentation copied from User's Manual
* Layout used in documentation for another sanitizers (ASan, MSan etc.)
* Text written from scratch
* Small parts taken from Michael Morrison's attempt at creating UBSan
  page:
  http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20141215/249503.html

Reviewers: kcc, rsmith, silvas

Subscribers: tberghammer, danalbert, srhines, kcc

Differential Revision: http://reviews.llvm.org/D15217

llvm-svn: 254733
2015-12-04 17:30:29 +00:00