On Mon, Mar 4, 2024 at 1:43 PM Fangrui Song <mask...@google.com> wrote:
>
> From: Fangrui Song <mask...@gcc.gnu.org>
>
> -fno-pic -mfdpic generated code is like regular -fno-pic, not suitable
> for FDPIC (absolute addressing for symbol references and no function
> descriptor). The sh port simply upgrades -fno-pic to -fpie by setting
> flag_pic. Let's follow suit.
>
> Link:
> https://inbox.sourceware.org/gcc-patches/20150913165303.gc17...@brightrain.aerifal.cx/
>
> gcc/ChangeLog:
>
> * config/arm/arm.cc (arm_option_override): Set flag_pic if
> TARGET_FDPIC.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.target/arm/fdpic-pie.c: New test.
> ---
> gcc/config/arm/arm.cc | 6 +++++
> gcc/testsuite/gcc.target/arm/fdpic-pie.c | 30 ++++++++++++++++++++++++
> 2 files changed, 36 insertions(+)
> create mode 100644 gcc/testsuite/gcc.target/arm/fdpic-pie.c
>
> diff --git a/gcc/config/arm/arm.cc b/gcc/config/arm/arm.cc
> index 1cd69268ee9..f2fd3cce48c 100644
> --- a/gcc/config/arm/arm.cc
> +++ b/gcc/config/arm/arm.cc
> @@ -3682,6 +3682,12 @@ arm_option_override (void)
> arm_pic_register = FDPIC_REGNUM;
> if (TARGET_THUMB1)
> sorry ("FDPIC mode is not supported in Thumb-1 mode");
> +
> + /* FDPIC code is a special form of PIC, and the vast majority of code
> + generation constraints that apply to PIC also apply to FDPIC, so we
> + set flag_pic to avoid the need to check TARGET_FDPIC everywhere
> + flag_pic is checked. */
> + flag_pic = 2;
> }
Been a while since I looked at this stuff but should this not be
flag_pie being set rather than flag_pic here if the expectation is to
turn -fno-PIC -mfdpic into fPIE ?
>
> if (arm_pic_register_string != NULL)
> diff --git a/gcc/testsuite/gcc.target/arm/fdpic-pie.c
> b/gcc/testsuite/gcc.target/arm/fdpic-pie.c
> new file mode 100644
> index 00000000000..909db8bce74
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/arm/fdpic-pie.c
> @@ -0,0 +1,30 @@
> +// { dg-do compile }
> +// { dg-options "-O2 -fno-pic -mfdpic" }
> +// { dg-skip-if "-mpure-code and -fPIC incompatible" { *-*-* } {
> "-mpure-code" } }
> +
> +__attribute__((visibility("hidden"))) void hidden_fun(void);
> +void fun(void);
> +__attribute__((visibility("hidden"))) extern int hidden_var;
> +extern int var;
> +__attribute__((visibility("hidden"))) const int ro_hidden_var = 42;
> +
> +// { dg-final { scan-assembler "hidden_fun\\(GOTOFFFUNCDESC\\)" } }
> +void *addr_hidden_fun(void) { return hidden_fun; }
> +
> +// { dg-final { scan-assembler "fun\\(GOTFUNCDESC\\)" } }
> +void *addr_fun(void) { return fun; }
> +
> +// { dg-final { scan-assembler "hidden_var\\(GOT\\)" } }
> +void *addr_hidden_var(void) { return &hidden_var; }
> +
> +// { dg-final { scan-assembler "var\\(GOT\\)" } }
> +void *addr_var(void) { return &var; }
> +
> +// { dg-final { scan-assembler ".LANCHOR0\\(GOT\\)" } }
> +const int *addr_ro_hidden_var(void) { return &ro_hidden_var; }
> +
> +// { dg-final { scan-assembler "hidden_var\\(GOT\\)" } }
> +int read_hidden_var(void) { return hidden_var; }
> +
> +// { dg-final { scan-assembler "var\\(GOT\\)" } }
> +int read_var(void) { return var; }
> --
> 2.44.0.rc1.240.g4c46232300-goog
>
