On Tue, 2020-08-18 at 08:24 +, David Laight wrote:
> From: Nick Desaulniers
> > Sent: 17 August 2020 19:37
> ..
> > That said, this libcall optimization/transformation (sprintf->stpcpy)
> > does look useful to me.
>
> I'd rather get a cow if I ask for a cow...
>
> Maybe checkpatch (etc)
On Mon, Aug 17, 2020 at 1:13 PM Arvind Sankar wrote:
>
> On Mon, Aug 17, 2020 at 11:36:49AM -0700, Nick Desaulniers wrote:
> > > > Though I don't understand the original issue, with -ffreestanding,
> > > > sprintf shouldn't have been turned into strcpy in the first place.
> >
> > Huh? The
On Mon, Aug 17, 2020 at 11:36:49AM -0700, Nick Desaulniers wrote:
> > > Though I don't understand the original issue, with -ffreestanding,
> > > sprintf shouldn't have been turned into strcpy in the first place.
>
> Huh? The original issue for this thread is because `-ffreestanding`
> *isn't*
On Mon, Aug 17, 2020 at 10:14:43AM -0700, Sami Tolvanen wrote:
> I just confirmed that adding -fno-builtin-stpcpy to KBUILD_CFLAGS does
> work with LTO as well.
Oh, I read this out of order; sorry! Yes, if -fno-builtin-stpcpy works,
let's use that instead. Doesn't that solve it too?
--
Kees
On Mon, Aug 17, 2020 at 11:36:49AM -0700, Nick Desaulniers wrote:
> That said, this libcall optimization/transformation (sprintf->stpcpy)
> does look useful to me. Kees, do you have thoughts on me providing
> the implementation without exposing it in a header vs using
> -fno-builtin-stpcpy? (I
On Mon, Aug 17, 2020 at 10:14 AM Sami Tolvanen wrote:
>
> On Sun, Aug 16, 2020 at 8:02 AM Arvind Sankar wrote:
> >
> > On Sun, Aug 16, 2020 at 07:22:35AM +0200, Sedat Dilek wrote:
> > > On Sun, Aug 16, 2020 at 2:19 AM 'Fangrui Song' via Clang Built Linux
> > > wrote:
> > > >
> > > > Adding a
On Sun, Aug 16, 2020 at 8:02 AM Arvind Sankar wrote:
>
> On Sun, Aug 16, 2020 at 07:22:35AM +0200, Sedat Dilek wrote:
> > On Sun, Aug 16, 2020 at 2:19 AM 'Fangrui Song' via Clang Built Linux
> > wrote:
> > >
> > > Adding a definition without a declaration for stpcpy looks good.
> > > Clang LTO
On Sun, Aug 16, 2020 at 07:22:35AM +0200, Sedat Dilek wrote:
> On Sun, Aug 16, 2020 at 2:19 AM 'Fangrui Song' via Clang Built Linux
> wrote:
> >
> > Adding a definition without a declaration for stpcpy looks good.
> > Clang LTO will work.
> >
> > (If the kernel does not want to provide these
On Sun, Aug 16, 2020 at 2:19 AM 'Fangrui Song' via Clang Built Linux
wrote:
>
> On 2020-08-15, 'Nick Desaulniers' via Clang Built Linux wrote:
> >On Sat, Aug 15, 2020 at 2:31 PM Joe Perches wrote:
> >>
> >> On Sat, 2020-08-15 at 14:28 -0700, Nick Desaulniers wrote:
> >> > On Sat, Aug 15, 2020 at
On 2020-08-15, 'Nick Desaulniers' via Clang Built Linux wrote:
On Sat, Aug 15, 2020 at 2:31 PM Joe Perches wrote:
On Sat, 2020-08-15 at 14:28 -0700, Nick Desaulniers wrote:
> On Sat, Aug 15, 2020 at 2:24 PM Joe Perches wrote:
> > On Sat, 2020-08-15 at 13:47 -0700, Nick Desaulniers wrote:
> >
On Fri, 2020-08-14 at 19:09 -0700, Nick Desaulniers wrote:
> LLVM implemented a recent "libcall optimization" that lowers calls to
> `sprintf(dest, "%s", str)` where the return value is used to
> `stpcpy(dest, str) - dest`. This generally avoids the machinery involved
> in parsing format strings.
On Sat, Aug 15, 2020 at 2:31 PM Joe Perches wrote:
>
> On Sat, 2020-08-15 at 14:28 -0700, Nick Desaulniers wrote:
> > On Sat, Aug 15, 2020 at 2:24 PM Joe Perches wrote:
> > > On Sat, 2020-08-15 at 13:47 -0700, Nick Desaulniers wrote:
> > > > On Sat, Aug 15, 2020 at 9:34 AM Kees Cook wrote:
> >
On Fri, Aug 14, 2020 at 07:09:44PM -0700, Nick Desaulniers wrote:
> LLVM implemented a recent "libcall optimization" that lowers calls to
> `sprintf(dest, "%s", str)` where the return value is used to
> `stpcpy(dest, str) - dest`. This generally avoids the machinery involved
> in parsing format
On Sat, Aug 15, 2020 at 9:34 AM Kees Cook wrote:
>
> On Fri, Aug 14, 2020 at 07:09:44PM -0700, Nick Desaulniers wrote:
> > LLVM implemented a recent "libcall optimization" that lowers calls to
> > `sprintf(dest, "%s", str)` where the return value is used to
> > `stpcpy(dest, str) - dest`. This
Yeah, sprintf calls should be replaced with something safer.
> Dňa 15. 8. 2020 o 18:34 užívateľ Kees Cook napísal:
>
> On Fri, Aug 14, 2020 at 07:09:44PM -0700, Nick Desaulniers wrote:
>> LLVM implemented a recent "libcall optimization" that lowers calls to
>> `sprintf(dest, "%s", str)` where
LLVM implemented a recent "libcall optimization" that lowers calls to
`sprintf(dest, "%s", str)` where the return value is used to
`stpcpy(dest, str) - dest`. This generally avoids the machinery involved
in parsing format strings. Calling `sprintf` with overlapping arguments
was clarified in ISO
On Fri, Aug 14, 2020 at 07:09:44PM -0700, Nick Desaulniers wrote:
> LLVM implemented a recent "libcall optimization" that lowers calls to
> `sprintf(dest, "%s", str)` where the return value is used to
> `stpcpy(dest, str) - dest`. This generally avoids the machinery involved
> in parsing format
On Sat, Aug 15, 2020 at 2:24 PM Joe Perches wrote:
>
> On Sat, 2020-08-15 at 13:47 -0700, Nick Desaulniers wrote:
> > On Sat, Aug 15, 2020 at 9:34 AM Kees Cook wrote:
> > > On Fri, Aug 14, 2020 at 07:09:44PM -0700, Nick Desaulniers wrote:
> > > > LLVM implemented a recent "libcall optimization"
-fno-builtin-stpcpy can be used to disable stpcpy but Nick at llvm bugzilla
wrote that these flags are broken with LTO.
> Dňa 15. 8. 2020 o 23:24 užívateľ Joe Perches napísal:
>
> On Sat, 2020-08-15 at 13:47 -0700, Nick Desaulniers wrote:
>>> On Sat, Aug 15, 2020 at 9:34 AM Kees Cook wrote:
On Sat, 2020-08-15 at 13:47 -0700, Nick Desaulniers wrote:
> On Sat, Aug 15, 2020 at 9:34 AM Kees Cook wrote:
> > On Fri, Aug 14, 2020 at 07:09:44PM -0700, Nick Desaulniers wrote:
> > > LLVM implemented a recent "libcall optimization" that lowers calls to
> > > `sprintf(dest, "%s", str)` where
On Sat, 2020-08-15 at 14:28 -0700, Nick Desaulniers wrote:
> On Sat, Aug 15, 2020 at 2:24 PM Joe Perches wrote:
> > On Sat, 2020-08-15 at 13:47 -0700, Nick Desaulniers wrote:
> > > On Sat, Aug 15, 2020 at 9:34 AM Kees Cook wrote:
> > > > On Fri, Aug 14, 2020 at 07:09:44PM -0700, Nick Desaulniers
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