commit cf0d4e41a94bae204a8c5d2490063d58cdb1d4e3
Author: Martin Sebor <msebor@redhat.com>
Date: Tue Feb 9 17:12:16 2021 -0700
Update new attribute malloc and document new and enhanced warnings.
@@ -179,21 +179,47 @@ a work-in-progress.</p>
<li>The existing
<a href="https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-malloc-function-attribute"><code>malloc</code></a>
attribute has been extended so that it can be used to identify
- allocator/deallocator API pairs. A new
- <a href="https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#-Wmismatched-dealloc"><code>-Wmismatched-dealloc</code></a>
- warning will complain about incorrect calls. Additionally, the
- static analyzer will use these attributes when checking for leaks,
- double-frees, use-after-frees, and similar issues.
+ allocator/deallocator API pairs. A pair of new
+ <a href="https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wmismatched-dealloc"><code>-Wmismatched-dealloc</code></a> and <a href="https://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Dialect-Options.html#index-Wmismatched-new-delete"><code>-Wmismatched-new-delete</code></a> warnings will complain
+ about mismatched calls, and <a href="https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wfree-nonheap-object"><code>-Wfree-nonheap-object</code></a> about deallocation calls with pointers not obtained from allocation
+ functions. Additionally, the static analyzer will use these
+ attributes when checking for leaks, double-frees, use-after-frees,
+ and similar issues.
</li>
</ul>
<li>New warnings:
<ul>
+ <li><a href="https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wmismatched-dealloc"><code>-Wmismatched-dealloc</code></a>,
+ enabled by default, warns about calls to deallocation functions
+ with pointers returned from mismatched allocation functions.
+ </li>
<li><a href="https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wsizeof-array-div"><code>-Wsizeof-array-div</code></a>,
enabled by <code>-Wall</code>, warns
about divisions of two sizeof operators when the first one is applied
to an array and the divisor does not equal the size of the array
element.
</li>
+ <li><a href="https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wstringop-overread"><code>-Wstringop-overread</code></a>,
+ enabled by default, warns about calls to string functions reading
+ past the end of the arrays passed to them as arguments. In prior
+ GCC releases most instances of his warning are diagnosed by
+ <code>-Wstringop-overflow</code>.
+ </li>
+ </ul>
+ </li>
+ <li>Enhancements to existing warnings:
+ <ul>
+ <li><a href="https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wfree-nonheap-object"><code>-Wfree-nonheap-object</code></a>
+ detects many more instances of calls to deallocation functions with
+ pointers not returned from a dynamic memory allocation function.
+ </li>
+ <li><a href="https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wmaybe-uninitialized"><code>-Wmaybe-uninitialized</code></a>
+ diagnoses passing pointers or references to uninitialized memory
+ to functions taking <code>const</code>-qualified arguments.
+ </li>
+ <li><a href="https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wuninitialized"><code>-Wuninitialized</code></a>
+ detects reads from uninitialized dynamically allocated memory.
+ </li>
</ul>
</li>
<li>
@@ -275,6 +301,22 @@ a work-in-progress.</p>
<li>Labels may appear before declarations and at the end of a
compound statement.</li>
</ul></li>
+ <li>New warnings:
+ <ul>
+ <li><a href="https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Warray-parameter"><code>-Warray-parameter</code></a>,
+ enabled by <code>-Wall</code>, warns about redeclarations of functions
+ with ordinary array arguments declared using inconsistent forms.
+ The warning also enables the detection of the likely out of bounds
+ accesses in calls to such functions with smaller arrays.
+ </li>
+ <li><a href="https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wvla-parameter"><code>-Wvla-parameter</code></a>,
+ enabled by <code>-Wall</code>, warns redeclarations of functions
+ with variable length array arguments declared using inconsistent
+ forms or with mismatched bounds. The warning also enables
+ the detection of the likely out of bounds accesses in calls to
+ such functions with smaller arrays.
+ </li>
+ </ul>
</ul>
<h3 id="cxx">C++</h3>
@@ -351,12 +393,27 @@ a work-in-progress.</p>
one is of enumeration type and the other is of a floating-point type,
as outlined in <em>[depr.arith.conv.enum]</em>.
</li>
+ <li><a href="https://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Dialect-Options.html#index-Wmismatched-new-delete"><code>-Wmismatched-new-delete</code></a>,
+ enabled by <code>-Wall</code>, warns about calls to C++
+ <code>operator delete</code> with pointers returned from mismatched
+ forms of <code>operator new</code> or from other mismatched allocation
+ functions.
+ </li>
<li><code>-Wvexing-parse</code>, enabled by default, warns about the most
vexing parse rule: the cases when a declaration looks like a variable
definition, but the C++ language requires it to be interpreted as a
function declaration.
</li>
</ul>
+ <li>Enhancements to existing warnings:
+ <ul>
+ <li><a href="https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wnonnull"><code>-Wnonnull</code></a>
+ considers the implicit <code>this</code> argument of every C++
+ nonstatic member function to have been implicitly declared with
+ attribute <code>nonnull</code> and triggers warnings for calls where
+ the pointer is null.
+ </li>
+ </ul>
</li>
</ul>