On Tue, Jan 16, 2024 at 11:47 PM Uros Bizjak <ubiz...@gmail.com> wrote:
>
> On Thu, Jan 11, 2024 at 7:24 PM Fangrui Song <mask...@google.com> wrote:
> >
> > Printing the raw symbol is useful in inline asm (e.g. in C++ to get the
> > mangled name). Similar constraints are available in other targets (e.g.
> > "S" for aarch64/riscv, "Cs" for m68k).
> >
> > There isn't a good way for x86 yet, e.g. "i" doesn't work for
> > PIC/-mcmodel=large. This patch adds "Ws". Here are possible use cases:
> >
> > ```
> > namespace ns { extern int var; }
> > asm (".pushsection .xxx,\"aw\"; .dc.a %0; .popsection" :: "Ws"(&var));
> > asm (".reloc ., BFD_RELOC_NONE, %0" :: "Ws"(&var));
> > ```
> >
> > gcc/ChangeLog:
> >
> > PR target/105576
> > * config/i386/constraints.md: Define constraint "Ws".
> > * doc/md.texi: Document it.
> >
> > gcc/testsuite/ChangeLog:
> >
> > * gcc.target/i386/asm-raw-symbol.c: New testcase.
>
> OK.
Hi Fangrui,
I pushed it for you with indentation changes in the commit log.
Thanks.
> Thanks,
> Uros.
>
> >
> > ---
> >
> > This obsoletes
> > https://gcc.gnu.org/pipermail/gcc-patches/2024-January/642580.html
> > I initially tried 'z', but Uros requested that a W prefix is used.
> > ---
> > gcc/config/i386/constraints.md | 4 ++++
> > gcc/doc/md.texi | 4 ++++
> > gcc/testsuite/gcc.target/i386/asm-raw-symbol.c | 13 +++++++++++++
> > 3 files changed, 21 insertions(+)
> > create mode 100644 gcc/testsuite/gcc.target/i386/asm-raw-symbol.c
> >
> > diff --git a/gcc/config/i386/constraints.md b/gcc/config/i386/constraints.md
> > index 0c6e662df25..280e4c8e36c 100644
> > --- a/gcc/config/i386/constraints.md
> > +++ b/gcc/config/i386/constraints.md
> > @@ -348,6 +348,10 @@ (define_constraint "Wf"
> > to double word size."
> > (match_operand 0 "x86_64_dwzext_immediate_operand"))
> >
> > +(define_constraint "Ws"
> > + "A symbolic reference or label reference."
> > + (match_code "const,symbol_ref,label_ref"))
> > +
> > (define_constraint "Z"
> > "32-bit unsigned integer constant, or a symbolic reference known
> > to fit that range (for immediate operands in zero-extending x86-64
> > diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
> > index 47a87d6ceec..b0c61925120 100644
> > --- a/gcc/doc/md.texi
> > +++ b/gcc/doc/md.texi
> > @@ -4275,6 +4275,10 @@ require non-@code{VOIDmode} immediate operands).
> > 128-bit integer constant where both the high and low 64-bit word
> > satisfy the @code{e} constraint.
> >
> > +@item Ws
> > +A symbolic reference or label reference.
> > +You can use the @code{%p} modifier to print the raw symbol.
> > +
> > @item Z
> > 32-bit unsigned integer constant, or a symbolic reference known
> > to fit that range (for immediate operands in zero-extending x86-64
> > diff --git a/gcc/testsuite/gcc.target/i386/asm-raw-symbol.c
> > b/gcc/testsuite/gcc.target/i386/asm-raw-symbol.c
> > new file mode 100644
> > index 00000000000..b7854567dd9
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/asm-raw-symbol.c
> > @@ -0,0 +1,13 @@
> > +/* { dg-do compile } */
> > +
> > +extern int var;
> > +
> > +void
> > +func (void)
> > +{
> > + __asm__ ("@ %p0" : : "Ws" (func));
> > + __asm__ ("@ %p0" : : "Ws" (&var + 1));
> > +}
> > +
> > +/* { dg-final { scan-assembler "@ func" } } */
> > +/* { dg-final { scan-assembler "@ var\\+4" } } */
> > --
> > 2.43.0.275.g3460e3d667-goog
> >
--
H.J.
