On Sun, Mar 14, 2021 at 11:49 AM Uros Bizjak <ubiz...@gmail.com> wrote:
>
> On Sat, Mar 13, 2021 at 8:39 PM H.J. Lu <hjl.to...@gmail.com> wrote:
> >
> > On Fri, Mar 12, 2021 at 8:37 AM Uros Bizjak <ubiz...@gmail.com> wrote:
> > >
> > > On Fri, Mar 12, 2021 at 2:20 PM H.J. Lu <hjl.to...@gmail.com> wrote:
> > > >
> > > > On Thu, Mar 11, 2021 at 11:21 PM Uros Bizjak <ubiz...@gmail.com> wrote:
> > > > >
> > > > > On Thu, Mar 11, 2021 at 11:22 PM H.J. Lu <hjl.to...@gmail.com> wrote:
> > > > > >
> > > > > > Update 'P' operand modifier for -fno-plt to support inline assembly
> > > > > > statements. In 64-bit, we can always load function address with
> > > > > > @GOTPCREL. In 32-bit, we load function address with @GOT only for
> > > > > > non-PIC since PIC register may not be available at call site.
> > > > > >
> > > > > > gcc/
> > > > > >
> > > > > > PR target/99504
> > > > > > * config/i386/i386.c (ix86_print_operand): Update 'P'
> > > > > > handling
> > > > > > for -fno-plt.
> > > > > >
> > > > > > gcc/testsuite/
> > > > > >
> > > > > > PR target/99504
> > > > > > * gcc.target/i386/pr99530-1.c: New test.
> > > > > > * gcc.target/i386/pr99530-2.c: Likewise.
> > > > > > * gcc.target/i386/pr99530-3.c: Likewise.
> > > > > > * gcc.target/i386/pr99530-4.c: Likewise.
> > > > > > * gcc.target/i386/pr99530-5.c: Likewise.
> > > > > > * gcc.target/i386/pr99530-6.c: Likewise.
> > > > > > ---
> > > > > > gcc/config/i386/i386.c | 33
> > > > > > +++++++++++++++++++++--
> > > > > > gcc/testsuite/gcc.target/i386/pr99530-1.c | 11 ++++++++
> > > > > > gcc/testsuite/gcc.target/i386/pr99530-2.c | 11 ++++++++
> > > > > > gcc/testsuite/gcc.target/i386/pr99530-3.c | 11 ++++++++
> > > > > > gcc/testsuite/gcc.target/i386/pr99530-4.c | 11 ++++++++
> > > > > > gcc/testsuite/gcc.target/i386/pr99530-5.c | 11 ++++++++
> > > > > > gcc/testsuite/gcc.target/i386/pr99530-6.c | 11 ++++++++
> > > > > > 7 files changed, 97 insertions(+), 2 deletions(-)
> > > > > > create mode 100644 gcc/testsuite/gcc.target/i386/pr99530-1.c
> > > > > > create mode 100644 gcc/testsuite/gcc.target/i386/pr99530-2.c
> > > > > > create mode 100644 gcc/testsuite/gcc.target/i386/pr99530-3.c
> > > > > > create mode 100644 gcc/testsuite/gcc.target/i386/pr99530-4.c
> > > > > > create mode 100644 gcc/testsuite/gcc.target/i386/pr99530-5.c
> > > > > > create mode 100644 gcc/testsuite/gcc.target/i386/pr99530-6.c
> > > > > >
> > > > > > diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
> > > > > > index 2603333f87b..8733fcecf65 100644
> > > > > > --- a/gcc/config/i386/i386.c
> > > > > > +++ b/gcc/config/i386/i386.c
> > > > > > @@ -12701,7 +12701,8 @@ print_reg (rtx x, int code, FILE *file)
> > > > > > y -- print "st(0)" instead of "st" as a register.
> > > > > > d -- print duplicated register operand for AVX instruction.
> > > > > > D -- print condition for SSE cmp instruction.
> > > > > > - P -- if PIC, print an @PLT suffix.
> > > > > > + P -- if PIC, print an @PLT suffix. For -fno-plt, load function
> > > > > > + address from GOT.
> > > > > > p -- print raw symbol name.
> > > > > > X -- don't print any sort of PIC '@' suffix for a symbol.
> > > > > > & -- print some in-use local-dynamic symbol name.
> > > > > > @@ -13445,7 +13446,35 @@ ix86_print_operand (FILE *file, rtx x, int
> > > > > > code)
> > > > > > x = const0_rtx;
> > > > > > }
> > > > > >
> > > > > > - if (code != 'P' && code != 'p')
> > > > > > + if (code == 'P')
> > > > > > + {
> > > > > > + if (current_output_insn == NULL_RTX
> > > > > > + && (TARGET_64BIT || (!flag_pic &&
> > > > > > HAVE_AS_IX86_GOT32X))
> > > > > > + && !TARGET_PECOFF
> > > > > > + && !TARGET_MACHO
> > > > > > + && ix86_cmodel != CM_LARGE
> > > > > > + && ix86_cmodel != CM_LARGE_PIC
> > > > > > + && GET_CODE (x) == SYMBOL_REF
> > > > > > + && SYMBOL_REF_FUNCTION_P (x)
> > > > > > + && (!flag_plt
> > > > > > + || (SYMBOL_REF_DECL (x)
> > > > > > + && lookup_attribute ("noplt",
> > > > > > + DECL_ATTRIBUTES
> > > > > > (SYMBOL_REF_DECL (x)))))
> > > > > > + && !SYMBOL_REF_LOCAL_P (x))
> > > > > > + {
> > > > > > + /* For inline assembly statement, load function
> > > > > > address
> > > > > > + from GOT with 'P' operand modifier to avoid PLT.
> > > > > > + NB: This works only with call or jmp. */
> > > > > > + const char *xasm;
> > > > > > + if (TARGET_64BIT)
> > > > > > + xasm = "{*%p0@GOTPCREL(%%rip)|[QWORD PTR
> > > > > > %p0@GOTPCREL[rip]]}";
> > > > > > + else
> > > > > > + xasm = "{*%p0@GOT|[DWORD PTR %p0@GOT]}";
> > > > > > + output_asm_insn (xasm, &x);
> > > > > > + return;
> > > > >
> > > > > This should be handled in output_pic_addr_const.
> > > > >
> > > >
> > > > call/jmp are special and are handled by ix86_output_call_insn,
> > > > not output_pic_addr_const.
> > >
> > > I see, the call_insn is output using output_asm_insn, which I think is
> > > not appropriate in ix86_print_operand. Probably you should introduce a
> > > new helper function and output a GOTPCREL reloc there. Something like
> > > x86_print_operand with 'A' code, calling output_addr_const and
> > > appending @GOTPCREL. Perhaps some parts of ix86_print_opreands can be
> > > used instead.
> >
> > Done. Here is the updated patch. Tested on Linux/x86-64. OK for master?
>
> I don't understand the purpose of the current_output_insn check and I
> don't know if the usage of current_output_insn is correct. The
> comments are not helpful either, and no other target uses this
> variable in the way you propose. Can you please elaborate the reason
> and the purpose of the check a bit more?
>
> Uros.
Originally, ix86_force_load_from_GOT_p is only for non-PIC. My patch extended
it to inline assembly statements where current_output_insn == NULL and PIC is
allowed in 64-bit.
--
H.J.
