Commit Graph

4 Commits

Author SHA1 Message Date
serge-sans-paille 0f0e31cf51 Update inline builtin handling to honor gnu inline attribute
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
2021-10-04 22:26:25 +02:00
serge-sans-paille c3717b6858 Simplify handling of builtin with inline redefinition
(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
2021-09-28 21:00:47 +02:00
Kevin Athey 0d76d4833d Revert "Simplify handling of builtin with inline redefinition"
This reverts commit 3d6f49a569.

Broke bot: https://lab.llvm.org/buildbot/#/builders/5/builds/12360
2021-09-28 11:30:37 -07:00
serge-sans-paille 3d6f49a569 Simplify handling of builtin with inline redefinition
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
2021-09-28 13:24:25 +02:00