This is the mail archive of the
gcc-help@gcc.gnu.org
mailing list for the GCC project.
Re: SuperH target not emitting instructions to use frame pointer?
Looks like I have made some typos. My apologies.
Seeing above that I passed '--enable-frame-pointer', GCC still does
not use the frame pointer. I even went in and enabled the C
preprocessor macro, SUBTARGET_FRAME_POINTER_REQUIRED which forces
TARGET_FRAME_POINTER_REQUIRED to return TRUE. I didn't use the
machine-description macro FRAME_POINTER_REQUIRED. Could that also be
it? Where would I set this?
Also, I'm recompiling GCC by passing the flag '--without-dwarf2'. In
gcc/config/sh.c, there is a boolean checking if the debugging type
DWARF-2 is preferred: flag_omit_frame_pointer =
(PREFERRED_DEBUGGING_TYPE == DWARF2_DEBUG)
I'll report back.
On Sat, Jun 9, 2012 at 9:04 AM, Israel Jacquez <mrkotfw@gmail.com> wrote:
> Hello everyone,
>
> Version: GCC 4.3.6
> Target: sh
> OS: GNU/Linux
> Flags passed to GCC configure:
> --enable-frame-pointer
> --disable-cld
> --disable-initfini-array
> --disable-largefile
> --disable-libstdcxx-pch
> --disable-multilib
> --disable-multilib
> --disable-nls
> --disable-objc-gc
> --disable-rpath
> --disable-shared
> --disable-threads
> --disable-tls
> --disable-win32-registry
> --enable-decimal-float=no
> --enable-languages=c,c++
> --enable-static
> --program-prefix="sh-elf-"
> --target="sh-elf"
> --with-gcc
> --with-gnu-as
> --with-gnu-ld
> --with-newlib
>
> On this architecture, the r14 register is considered to be the frame
> pointer register. The "pr" register is the procedure register that
> holds the return address. The "JSR" appropriately sets the "pr"
> register while "JMP" or any of the branch instructions do not.
>
> The flags I've used to compile my binaries (no ELF executables):
> -O2 -fno-omit-frame-pointer
>
> Seeing above that I passed '--enable-frame-pointer', GCC still does
> not use the frame pointer. I even when in and enabled the C
> preprocessor macro, SUBTARGET_FRAME_POINTER_REQUIRED which forces
> FRAME_POINTER_REQUIRED to return TRUE. I didn't use the
> machine-description macro FRAME_POINTER_REQUIRED. Could that also be
> it? Where would I set this?
>
> The ONLY way it works is if EVERY function has the following
> attribute: '__attribute__((optimize("-fno-omit-frame-pointer")))', but
> I MUST use the -O2 optimization level or else the frame pointer will
> not be used again.
>
>
> Am I missing something important here? I would simply like to have
> -fomit-frame-pointer and -fno-frame-pointer work as expected.