================
@@ -4122,6 +4122,9 @@ def RestrictDocs : Documentation {
The ``malloc`` attribute indicates that the function acts like a system memory
allocation function, returning a pointer to allocated storage disjoint from the
storage for any other object accessible to the caller.
+
+The form of ``malloc`` with one or two arguments (supported by GCC 11) is
+currently ignored by Clang.
----------------
aloisklink wrote:
In this PR, it's completely ignored, it's not even added to the Clang AST.
It just reaches the end of this function where nothing happens (let me know if
I can improve the comment!):
https://github.com/llvm/llvm-project/blob/f9c914729a5f5ac7f8b61ea2d39509ff0236a228/clang/lib/Sema/SemaDeclAttr.cpp#L2084-L2087
We can't treat it as if has no arguments because in GCC it means two different
things:
- `__attribute__((malloc))` with no args means the return value is guaranteed
not to alias to any other pointer (aka like [`__declspec(restrict)` in
MSVC](https://learn.microsoft.com/en-us/cpp/cpp/restrict?view=msvc-170)) and
that the function will normally return non-`NULL`, allowing optimizations,
- `__attribute__((malloc(deallocator)))` instead says the returned pointer
should be deallocated by the specified deallocator, allowing a static analyzer
to print warnings.
See the `malloc` section of
https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html for more
info.
To be honest, I feel like GCC should have given the one/two argument form a
different attribute name to make things less confusing, but GCC 11 has already
been out for years unfortunately.
https://github.com/llvm/llvm-project/pull/68059
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