Messages in this thread | | | Date | Wed, 3 Jun 2020 21:23:53 +0200 | From | Marco Elver <> | Subject | Re: [PATCH v5 00/18] Rework READ_ONCE() to improve codegen |
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On Wed, 03 Jun 2020, Borislav Petkov wrote:
> On Thu, May 14, 2020 at 12:05:38PM +0100, Will Deacon wrote: > > Talking off-list, Clang >= 7 is pretty reasonable wrt inlining decisions > > and the behaviour for __always_inline is: > > > > * An __always_inline function inlined into a __no_sanitize function is > > not instrumented > > * An __always_inline function inlined into an instrumented function is > > instrumented > > * You can't mark a function as both __always_inline __no_sanitize, because > > __no_sanitize functions are never inlined > > > > GCC, on the other hand, may still inline __no_sanitize functions and then > > subsequently instrument them. > > Yeah, about that: I've been looking for a way to trigger this so that > I can show preprocessed source to gcc people. So do you guys have a > .config or somesuch I can try?
For example take this:
int x;
static inline __attribute__((no_sanitize_thread)) void do_not_sanitize(void) { x++; }
void sanitize_this(void) { do_not_sanitize(); }
Then
gcc-10 -O3 -fsanitize=thread -o example.o -c example.c objdump -D example.o
will show that do_not_sanitize() was inlined into sanitize_this() and is instrumented. (With Clang this doesn't happen.)
Hope this is enough.
Thanks, -- Marco
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