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Re: [PATCH] PR target/66232: -fPIC -fno-plt -mx32 fails to generate indirect branch via GOT


On Thu, May 21, 2015 at 2:59 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> X32 doesn't support indirect branch via 32-bit memory slot since
> indirect branch will load 64-bit address from 64-bit memory slot.
> Since x32 GOT slot is 64-bit, we should allow indirect branch via GOT
> slot for x32.
>
> I am testing it on x32.  OK for master if there is no regression?
>
> Thanks.
>
>
> H.J.
> --
> gcc/
>
>         PR target/66232
>         * config/i386/constraints.md (Bg): Add a constraint for x32
>         call and sibcall memory operand.
>         * config/i386/i386.md (*call_x32): New pattern.
>         (*sibcall_x32): Likewise.
>         (*call_value_x32): Likewise.
>         (*sibcall_value_x32): Likewise.
>         * config/i386/predicates.md (x32_sibcall_memory_operand): New
>         predicate.
>         (x32_call_insn_operand): Likewise.
>         (x32_sibcall_insn_operand): Likewise.
>
> gcc/testsuite/
>
>         PR target/66232
>         * gcc.target/i386/pr66232-1.c: New test.
>         * gcc.target/i386/pr66232-2.c: Likewise.
>         * gcc.target/i386/pr66232-3.c: Likewise.
>         * gcc.target/i386/pr66232-4.c: Likewise.

OK.

maybe you should use match_code some more in x32_sibcall_memory_operand, e.g.

(match_code "constant" "0")
(match_code "unspec" "00")

But it is up to you, since XINT doesn't fit in this scheme...

Thanks,
Uros.

>  gcc/config/i386/constraints.md            |  6 ++++++
>  gcc/config/i386/i386.md                   | 36 +++++++++++++++++++++++++++++++
>  gcc/config/i386/predicates.md             | 26 ++++++++++++++++++++++
>  gcc/testsuite/gcc.target/i386/pr66232-1.c | 13 +++++++++++
>  gcc/testsuite/gcc.target/i386/pr66232-2.c | 14 ++++++++++++
>  gcc/testsuite/gcc.target/i386/pr66232-3.c | 13 +++++++++++
>  gcc/testsuite/gcc.target/i386/pr66232-4.c | 13 +++++++++++
>  7 files changed, 121 insertions(+)
>  create mode 100644 gcc/testsuite/gcc.target/i386/pr66232-1.c
>  create mode 100644 gcc/testsuite/gcc.target/i386/pr66232-2.c
>  create mode 100644 gcc/testsuite/gcc.target/i386/pr66232-3.c
>  create mode 100644 gcc/testsuite/gcc.target/i386/pr66232-4.c
>
> diff --git a/gcc/config/i386/constraints.md b/gcc/config/i386/constraints.md
> index 2271bd1..7be8917 100644
> --- a/gcc/config/i386/constraints.md
> +++ b/gcc/config/i386/constraints.md
> @@ -146,10 +146,16 @@
>   "@internal Lower SSE register when avoiding REX prefix and all SSE registers otherwise.")
>
>  ;; We use the B prefix to denote any number of internal operands:
> +;;  g  Call and sibcall memory operand, valid for TARGET_X32
>  ;;  s  Sibcall memory operand, not valid for TARGET_X32
>  ;;  w  Call memory operand, not valid for TARGET_X32
>  ;;  z  Constant call address operand.
>
> +(define_constraint "Bg"
> +  "@internal Call/sibcall memory operand for x32."
> +  (and (match_test "TARGET_X32")
> +       (match_operand 0 "x32_sibcall_memory_operand")))
> +
>  (define_constraint "Bs"
>    "@internal Sibcall memory operand."
>    (and (not (match_test "TARGET_X32"))
> diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
> index aefca43..a1ae05a 100644
> --- a/gcc/config/i386/i386.md
> +++ b/gcc/config/i386/i386.md
> @@ -11659,6 +11659,14 @@
>    "* return ix86_output_call_insn (insn, operands[0]);"
>    [(set_attr "type" "call")])
>
> +(define_insn "*call_x32"
> +  [(call (mem:QI (zero_extend:DI
> +                  (match_operand:SI 0 "x32_call_insn_operand" "Bg")))
> +        (match_operand 1))]
> +  "TARGET_X32 && !SIBLING_CALL_P (insn)"
> +  "* return ix86_output_call_insn (insn, operands[0]);"
> +  [(set_attr "type" "call")])
> +
>  (define_insn "*sibcall"
>    [(call (mem:QI (match_operand:W 0 "sibcall_insn_operand" "UBsBz"))
>          (match_operand 1))]
> @@ -11666,6 +11674,14 @@
>    "* return ix86_output_call_insn (insn, operands[0]);"
>    [(set_attr "type" "call")])
>
> +(define_insn "*sibcall_x32"
> +  [(call (mem:QI (zero_extend:DI
> +                  (match_operand:SI 0 "x32_sibcall_insn_operand" "Bg")))
> +        (match_operand 1))]
> +  "TARGET_X32 && SIBLING_CALL_P (insn)"
> +  "* return ix86_output_call_insn (insn, operands[0]);"
> +  [(set_attr "type" "call")])
> +
>  (define_insn "*sibcall_memory"
>    [(call (mem:QI (match_operand:W 0 "memory_operand" "m"))
>          (match_operand 1))
> @@ -11825,6 +11841,16 @@
>    "* return ix86_output_call_insn (insn, operands[1]);"
>    [(set_attr "type" "callv")])
>
> +(define_insn "*call_value_x32"
> +  [(set (match_operand 0)
> +       (call (mem:QI
> +               (zero_extend:DI
> +                 (match_operand:SI 1 "x32_call_insn_operand" "Bg")))
> +             (match_operand 2)))]
> +  "TARGET_X32 && !SIBLING_CALL_P (insn)"
> +  "* return ix86_output_call_insn (insn, operands[1]);"
> +  [(set_attr "type" "callv")])
> +
>  (define_insn "*sibcall_value"
>    [(set (match_operand 0)
>         (call (mem:QI (match_operand:W 1 "sibcall_insn_operand" "UBsBz"))
> @@ -11833,6 +11859,16 @@
>    "* return ix86_output_call_insn (insn, operands[1]);"
>    [(set_attr "type" "callv")])
>
> +(define_insn "*sibcall_value_x32"
> +  [(set (match_operand 0)
> +       (call (mem:QI
> +               (zero_extend:DI
> +                 (match_operand:SI 1 "x32_sibcall_insn_operand" "Bg")))
> +             (match_operand 2)))]
> +  "TARGET_X32 && SIBLING_CALL_P (insn)"
> +  "* return ix86_output_call_insn (insn, operands[1]);"
> +  [(set_attr "type" "callv")])
> +
>  (define_insn "*sibcall_value_memory"
>    [(set (match_operand 0)
>         (call (mem:QI (match_operand:W 1 "memory_operand" "m"))
> diff --git a/gcc/config/i386/predicates.md b/gcc/config/i386/predicates.md
> index 26dd3e1..40fdd20 100644
> --- a/gcc/config/i386/predicates.md
> +++ b/gcc/config/i386/predicates.md
> @@ -606,6 +606,32 @@
>         (and (not (match_test "TARGET_X32"))
>             (match_operand 0 "sibcall_memory_operand"))))
>
> +;; Return true if OP is a memory operand that can be used in x32 calls
> +;; and sibcalls.  Only th 64-bit GOT slot is allowed.
> +(define_predicate "x32_sibcall_memory_operand"
> +  (and (match_operand 0 "memory_operand")
> +       (match_test "CONSTANT_P (XEXP (op, 0))")
> +       (match_test "GET_CODE (XEXP (XEXP (op, 0), 0)) == UNSPEC")
> +       (match_test "XINT (XEXP (XEXP (op, 0), 0), 1) == UNSPEC_GOTPCREL")))
> +
> +;; Test for a valid operand for an x32 call instruction.
> +;; Allow constant call address operands in Pmode only.
> +(define_special_predicate "x32_call_insn_operand"
> +  (ior (match_test "constant_call_address_operand
> +                    (op, mode == VOIDmode ? mode : Pmode)")
> +       (match_operand 0 "call_register_no_elim_operand")
> +       (and (match_test "TARGET_X32")
> +           (match_operand 0 "x32_sibcall_memory_operand"))))
> +
> +;; Similarly, but for tail x32 calls, in which we cannot allow memory
> +;; references.
> +(define_special_predicate "x32_sibcall_insn_operand"
> +  (ior (match_test "constant_call_address_operand
> +                    (op, mode == VOIDmode ? mode : Pmode)")
> +       (match_operand 0 "register_no_elim_operand")
> +       (and (match_test "TARGET_X32")
> +           (match_operand 0 "x32_sibcall_memory_operand"))))
> +
>  ;; Match exactly zero.
>  (define_predicate "const0_operand"
>    (match_code "const_int,const_wide_int,const_double,const_vector")
> diff --git a/gcc/testsuite/gcc.target/i386/pr66232-1.c b/gcc/testsuite/gcc.target/i386/pr66232-1.c
> new file mode 100644
> index 0000000..ba4a5ef
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr66232-1.c
> @@ -0,0 +1,13 @@
> +/* { dg-do compile { target *-*-linux* } } */
> +/* { dg-options "-O2 -fpic -fno-plt" } */
> +
> +extern void bar (void);
> +
> +void
> +foo (void)
> +{
> +  bar ();
> +}
> +
> +/* { dg-final { scan-assembler "jmp\[ \t\]*.bar@GOTPCREL" { target { ! ia32 } } } } */
> +/* { dg-final { scan-assembler "call\[ \t\]*.bar@GOT\\(" { target ia32 } } } */
> diff --git a/gcc/testsuite/gcc.target/i386/pr66232-2.c b/gcc/testsuite/gcc.target/i386/pr66232-2.c
> new file mode 100644
> index 0000000..f05d7c5
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr66232-2.c
> @@ -0,0 +1,14 @@
> +/* { dg-do compile { target *-*-linux* } } */
> +/* { dg-options "-O2 -fpic -fno-plt" } */
> +
> +extern void bar (void);
> +
> +int
> +foo (void)
> +{
> +  bar ();
> +  return 0;
> +}
> +
> +/* { dg-final { scan-assembler "call\[ \t\]*.bar@GOTPCREL" { target { ! ia32 } } } } */
> +/* { dg-final { scan-assembler "call\[ \t\]*.bar@GOT\\(" { target ia32 } } } */
> diff --git a/gcc/testsuite/gcc.target/i386/pr66232-3.c b/gcc/testsuite/gcc.target/i386/pr66232-3.c
> new file mode 100644
> index 0000000..ee3176c
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr66232-3.c
> @@ -0,0 +1,13 @@
> +/* { dg-do compile { target *-*-linux* } } */
> +/* { dg-options "-O2 -fpic -fno-plt" } */
> +
> +extern int bar (void);
> +
> +int
> +foo (void)
> +{
> +  return bar ();
> +}
> +
> +/* { dg-final { scan-assembler "jmp\[ \t\]*.bar@GOTPCREL" { target { ! ia32 } } } } */
> +/* { dg-final { scan-assembler "call\[ \t\]*.bar@GOT\\(" { target ia32 } } } */
> diff --git a/gcc/testsuite/gcc.target/i386/pr66232-4.c b/gcc/testsuite/gcc.target/i386/pr66232-4.c
> new file mode 100644
> index 0000000..5fa0ded
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr66232-4.c
> @@ -0,0 +1,13 @@
> +/* { dg-do compile { target *-*-linux* } } */
> +/* { dg-options "-O2 -fpic -fno-plt" } */
> +
> +extern int bar (void);
> +
> +int
> +foo (void)
> +{
> +  return bar () + 1;
> +}
> +
> +/* { dg-final { scan-assembler "call\[ \t\]*.bar@GOTPCREL" { target { ! ia32 } } } } */
> +/* { dg-final { scan-assembler "call\[ \t\]*.bar@GOT\\(" { target ia32 } } } */
> --
> 2.1.0
>


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