llvm-capstone/clang/docs/SanitizerSpecialCaseList.rst
Vlad Tsyrklevich 2eccdab308 Allow specifying sanitizers in blacklists
Summary:
This is the follow-up patch to D37924.

This change refactors clang to use the the newly added section headers
in SpecialCaseList to specify which sanitizers blacklists entries
should apply to, like so:

  [cfi-vcall]
  fun:*bad_vcall*
  [cfi-derived-cast|cfi-unrelated-cast]
  fun:*bad_cast*

The SanitizerSpecialCaseList class has been added to allow querying by
SanitizerMask, and SanitizerBlacklist and its downstream users have been
updated to provide that information. Old blacklists not using sections
will continue to function identically since the blacklist entries will
be placed into a '[*]' section by default matching against all
sanitizers.

Reviewers: pcc, kcc, eugenis, vsk

Reviewed By: eugenis

Subscribers: dberris, cfe-commits, mgorny

Differential Revision: https://reviews.llvm.org/D37925

llvm-svn: 314171
2017-09-25 22:11:12 +00:00

96 lines
3.3 KiB
ReStructuredText

===========================
Sanitizer special case list
===========================
.. contents::
:local:
Introduction
============
This document describes the way to disable or alter the behavior of
sanitizer tools for certain source-level entities by providing a special
file at compile-time.
Goal and usage
==============
User of sanitizer tools, such as :doc:`AddressSanitizer`, :doc:`ThreadSanitizer`
or :doc:`MemorySanitizer` may want to disable or alter some checks for
certain source-level entities to:
* speedup hot function, which is known to be correct;
* ignore a function that does some low-level magic (e.g. walks through the
thread stack, bypassing the frame boundaries);
* ignore a known problem.
To achieve this, user may create a file listing the entities they want to
ignore, and pass it to clang at compile-time using
``-fsanitize-blacklist`` flag. See :doc:`UsersManual` for details.
Example
=======
.. code-block:: bash
$ cat foo.c
#include <stdlib.h>
void bad_foo() {
int *a = (int*)malloc(40);
a[10] = 1;
}
int main() { bad_foo(); }
$ cat blacklist.txt
# Ignore reports from bad_foo function.
fun:bad_foo
$ clang -fsanitize=address foo.c ; ./a.out
# AddressSanitizer prints an error report.
$ clang -fsanitize=address -fsanitize-blacklist=blacklist.txt foo.c ; ./a.out
# No error report here.
Format
======
Blacklists consist of entries, optionally grouped into sections. Empty lines and
lines starting with "#" are ignored.
Section names are regular expressions written in square brackets that denote
which sanitizer the following entries apply to. For example, ``[address]``
specifies AddressSanitizer while ``[cfi-vcall|cfi-icall]`` specifies Control
Flow Integrity virtual and indirect call checking. Entries without a section
will be placed under the ``[*]`` section applying to all enabled sanitizers.
Entries contain an entity type, followed by a colon and a regular expression,
specifying the names of the entities, optionally followed by an equals sign and
a tool-specific category, e.g. ``fun:*ExampleFunc=example_category``. The
meaning of ``*`` in regular expression for entity names is different - it is
treated as in shell wildcarding. Two generic entity types are ``src`` and
``fun``, which allow users to specify source files and functions, respectively.
Some sanitizer tools may introduce custom entity types and categories - refer to
tool-specific docs.
.. code-block:: bash
# Lines starting with # are ignored.
# Turn off checks for the source file (use absolute path or path relative
# to the current working directory):
src:/path/to/source/file.c
# Turn off checks for a particular functions (use mangled names):
fun:MyFooBar
fun:_Z8MyFooBarv
# Extended regular expressions are supported:
fun:bad_(foo|bar)
src:bad_source[1-9].c
# Shell like usage of * is supported (* is treated as .*):
src:bad/sources/*
fun:*BadFunction*
# Specific sanitizer tools may introduce categories.
src:/special/path/*=special_sources
# Sections can be used to limit blacklist entries to specific sanitizers
[address]
fun:*BadASanFunc*
# Section names are regular expressions
[cfi-vcall|cfi-icall]
fun:*BadCfiCall
# Entries without sections are placed into [*] and apply to all sanitizers