| Message ID | 20230819003303.1744466-1-sstabellini@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | docs/misra: document gcc-specific behavior with shifting signed integers | expand |
On 19.08.2023 02:33, Stefano Stabellini wrote: > From: Stefano Stabellini <stefano.stabellini@amd.com> > > Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com> > --- > Changes in v2: > - use "shift" instead of << or >> > - use All Architectures (I haven't changed all the other instances of > x86/arm in the file yet) > --- > docs/misra/C-language-toolchain.rst | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/docs/misra/C-language-toolchain.rst b/docs/misra/C-language-toolchain.rst > index 785aed1eaf..f5ca7bd2c8 100644 > --- a/docs/misra/C-language-toolchain.rst > +++ b/docs/misra/C-language-toolchain.rst > @@ -200,6 +200,12 @@ The table columns are as follows: > - ARM64, X86_64 > - See Section "6.29 Designated Initializers" of GCC_MANUAL > > + * - Signed shift acts on negative numbers by sign extension > + - All architectures > + - See Section "4.5 Integers" of GCC_MANUAL. As an extension to the > + C language, GCC does not use the latitude given in C99 and C11 > + only to treat certain aspects of signed shift as undefined. I'm sorry, but that's still not what the doc says. Replacing << and >> by "shifts" was imo wrong. What's needed instead is that either this is split into two top-level bullet points (one for << and one for >>), or the first sub-bullet-point (which acts as kind of the title) be generalized, with the << and >> details fully moved to the "explanatory" sub-bullet-point. Jan
On Mon, 21 Aug 2023, Jan Beulich wrote: > On 19.08.2023 02:33, Stefano Stabellini wrote: > > From: Stefano Stabellini <stefano.stabellini@amd.com> > > > > Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com> > > --- > > Changes in v2: > > - use "shift" instead of << or >> > > - use All Architectures (I haven't changed all the other instances of > > x86/arm in the file yet) > > --- > > docs/misra/C-language-toolchain.rst | 6 ++++++ > > 1 file changed, 6 insertions(+) > > > > diff --git a/docs/misra/C-language-toolchain.rst b/docs/misra/C-language-toolchain.rst > > index 785aed1eaf..f5ca7bd2c8 100644 > > --- a/docs/misra/C-language-toolchain.rst > > +++ b/docs/misra/C-language-toolchain.rst > > @@ -200,6 +200,12 @@ The table columns are as follows: > > - ARM64, X86_64 > > - See Section "6.29 Designated Initializers" of GCC_MANUAL > > > > + * - Signed shift acts on negative numbers by sign extension > > + - All architectures > > + - See Section "4.5 Integers" of GCC_MANUAL. As an extension to the > > + C language, GCC does not use the latitude given in C99 and C11 > > + only to treat certain aspects of signed shift as undefined. > > I'm sorry, but that's still not what the doc says. Replacing << and >> by > "shifts" was imo wrong. What's needed instead is that either this is split > into two top-level bullet points (one for << and one for >>), or the first > sub-bullet-point (which acts as kind of the title) be generalized, with > the << and >> details fully moved to the "explanatory" sub-bullet-point. I think I got your point now
diff --git a/docs/misra/C-language-toolchain.rst b/docs/misra/C-language-toolchain.rst index 785aed1eaf..f5ca7bd2c8 100644 --- a/docs/misra/C-language-toolchain.rst +++ b/docs/misra/C-language-toolchain.rst @@ -200,6 +200,12 @@ The table columns are as follows: - ARM64, X86_64 - See Section "6.29 Designated Initializers" of GCC_MANUAL + * - Signed shift acts on negative numbers by sign extension + - All architectures + - See Section "4.5 Integers" of GCC_MANUAL. As an extension to the + C language, GCC does not use the latitude given in C99 and C11 + only to treat certain aspects of signed shift as undefined. + Translation Limits __________________