[Bug c/94236] New: -mcmodel=large does not work on aarch64

[baratharon at caesar dot elte.hu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94236

            Bug ID: 94236
           Summary: -mcmodel=large does not work on aarch64
           Product: gcc
           Version: 9.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: baratharon at caesar dot elte.hu
  Target Milestone: ---

Hello,

If I compile an object file with -mcmodel=large, then the compiler produces
short jumps to the function. I see R_AARCH64_CALL26 relocation in the object
file (via readelf), but I'd expect R_AARCH64_ABS64 or something equivalent like
R_AARCH64_MOVW_UABS_G0 (and their friends). The CALL26 is not the right
relocation in there.

For example, on x86_64, I get R_X86_64_64 relocation there, which is correct.
On armv7, I get R_ARM_MOVT_ABS and R_ARM_MOVW_ABS_NC, which is also correct.

See resources below.

TIA,
Aron



$ cat a.c
int func(void);
int main()
{
        return func();
}


$ aarch64-linux-gnu-gcc -static -fno-pie -fno-pic -mcmodel=large -c a.c

$ aarch64-linux-gnu-objdump -D a.o | grep func
   8:   94000000        bl      0 <func>

$ aarch64-linux-gnu-readelf -a a.o | grep func
000000000008  000b0000011b R_AARCH64_CALL26  0000000000000000 func + 0
    11: 0000000000000000     0 NOTYPE  GLOBAL DEFAULT  UND func

$ aarch64-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=aarch64-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/aarch64-linux-gnu/9.2.0/lto-wrapper
Target: aarch64-linux-gnu
Configured with: /build/aarch64-linux-gnu-gcc/src/gcc-9.2.0/configure
--prefix=/usr --program-prefix=aarch64-linux-gnu-
--with-local-prefix=/usr/aarch64-linux-gnu
--with-sysroot=/usr/aarch64-linux-gnu
--with-build-sysroot=/usr/aarch64-linux-gnu
--with-native-system-header-dir=/include --libdir=/usr/lib
--libexecdir=/usr/lib --target=aarch64-linux-gnu --host=x86_64-pc-linux-gnu
--build=x86_64-pc-linux-gnu --disable-nls --enable-languages=c,c++,fortran
--enable-shared --enable-threads=posix --with-system-zlib --with-isl
--enable-__cxa_atexit --disable-libunwind-exceptions --enable-clocale=gnu
--disable-libstdcxx-pch --disable-libssp --enable-gnu-unique-object
--enable-linker-build-id --enable-lto --enable-plugin
--enable-install-libiberty --with-linker-hash-style=gnu
--enable-gnu-indirect-function --disable-multilib --disable-werror
--enable-checking=release
Thread model: posix
gcc version 9.2.0 (GCC) 

$ uname -a
Linux ****** 4.18.14-arch1-1-ARCH #1 SMP PREEMPT Sat Oct 13 13:42:37 UTC 2018
x86_64 GNU/Linux