Per the GCC info page:
If the function is declared 'extern', then this definition of the
function is used only for inlining. In no case is the function
compiled as a standalone function, not even if you take its address
explicitly. Such an address becomes an external reference, as if
you had only declared the function, and had not defined it.
Respect that behavior for inline builtins: keep the original definition, and
generate a copy of the declaration suffixed by '.inline' that's only referenced
in direct call.
This fixes holes in c3717b6858.
Differential Revision: https://reviews.llvm.org/D111009
(This is a recommit of 3d6f49a569 that should no longer break validation since
bd379915de).
It is a common practice in glibc header to provide an inline redefinition of an
existing function. It is especially the case for fortified function.
Clang currently has an imperfect approach to the problem, using a combination of
trivially recursive function detection and noinline attribute.
Simplify the logic by suffixing these functions by `.inline` during codegen, so
that they are not recognized as builtin by llvm.
After that patch, clang passes all tests from https://github.com/serge-sans-paille/fortify-test-suite
Differential Revision: https://reviews.llvm.org/D109967
It is a common practice in glibc header to provide an inline redefinition of an
existing function. It is especially the case for fortified function.
Clang currently has an imperfect approach to the problem, using a combination of
trivially recursive function detection and noinline attribute.
Simplify the logic by suffixing these functions by `.inline` during codegen, so
that they are not recognized as builtin by llvm.
After that patch, clang passes all tests from https://github.com/serge-sans-paille/fortify-test-suite
Differential Revision: https://reviews.llvm.org/D109967
If a system header provides an (inline) implementation of some of their
function, clang still matches on the function name and generate the appropriate
llvm builtin, e.g. memcpy. This behavior is in line with glibc recommendation «
users may not provide their own version of symbols » but doesn't account for the
fact that glibc itself can provide inline version of some functions.
It is the case for the memcpy function when -D_FORTIFY_SOURCE=1 is on. In that
case an inline version of memcpy calls __memcpy_chk, a function that performs
extra runtime checks. Clang currently ignores the inline version and thus
provides no runtime check.
This code fixes the issue by detecting functions whose name is a builtin name
but also have an inline implementation.
Differential Revision: https://reviews.llvm.org/D71082
serge-sans-paille