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Update the user's manual for some of the new -fcatch-undefined-behavior features. 

llvm-svn: 162635
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Richard Smith 2012-08-25 00:44:02 +00:00
parent 3e056dea1b
commit f994353801
1 changed files with 17 additions and 5 deletions
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22
clang/docs/UsersManual.html
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@ -880,18 +880,30 @@ on runtime code generation to check for undefined behavior.</dt>
<dd>This option, which defaults to off, controls whether or not Clang
adds runtime checks for undefined runtime behavior. If a check fails,
<tt>__builtin_trap()</tt> is used to indicate failure.
The checks are:
The currently implemented checks include:
<ul>
<li>Subscripting where the static type of one operand is a variable
which is decayed from an array type and the other operand is
greater than the size of the array or less than zero.</li>
<li>Shift operators where the amount shifted is greater or equal to the
promoted bit-width of the left-hand-side or less than zero.</li>
<li>If control flow reaches __builtin_unreachable.
<li>When llvm implements more __builtin_object_size support, reads and
writes for objects that __builtin_object_size indicates we aren't
accessing valid memory. Bit-fields and vectors are not yet checked.
<li>If control flow reaches __builtin_unreachable.</li>
<li>Reads and writes for objects which are inappropriately aligned or are not
large enough (in cases where the size can be determined).
<li>Signed integer overflow, including all the checks added by <tt>-ftrapv</tt>
and also checking for signed left shift overflow.</li>
<li>Binding a reference to a storage location which is not of an appropriate
alignment or size (in cases where the size can be determined), or binding
a reference to an empty glvalue (a dereferenced null pointer).
<li>Class member access or member function call where the <tt>this</tt>
pointer is not of an appropriate alignment or size (in cases where the size
can be determined), or where it is null.</li>
</ul>
<p>The sizes of objects are determined using <tt>__builtin_object_size</tt>, and
consequently may be able to detect more problems at higher optimization levels.
Bit-fields and vectors are not yet checked.</p>
</dd>
<dt id="opt_faddress-sanitizer"><b>-f[no-]address-sanitizer</b>: