[PATCH 6/7] [gdb/testsuite] use -Ttext-segment for jit-elf tests

[Simon Marchi]

Just some formatting nits:

> @@ -96,6 +89,15 @@ update_locations (const void *const addr, int idx)
>  #define MAIN main
>  #endif
>  
> +/* Must be defined by .exp file when compiling to know
> +   what address to map the ELF binary to.  */
> +#ifndef LOAD_ADDRESS
> +#error "Must define LOAD_ADDRESS"
> +#endif
> +#ifndef LOAD_INCREMENT
> +#error "Must define LOAD_INCREMENT"
> +#endif
> +
>  /* Used to spin waiting for GDB.  */
>  volatile int wait_for_gdb = ATTACH;
>  #define WAIT_FOR_GDB while (wait_for_gdb)
> @@ -137,7 +139,8 @@ MAIN (int argc, char *argv[])
>  	  exit (1);
>  	}
>  
> -      const void *const addr = mmap (0, st.st_size, PROT_READ|PROT_WRITE,
> +      void* load_addr = (void*) (size_t) (LOAD_ADDRESS + (i-1) * LOAD_INCREMENT);
> +      const void *const addr = mmap (load_addr, st.st_size, PROT_READ|PROT_WRITE,
>  				     MAP_PRIVATE, fd, 0);

We try to use the same style in code for tests as code for GDB itself.  So

      void* load_addr = (void*) (size_t) (LOAD_ADDRESS + (i-1) * LOAD_INCREMENT);

should be

      void *load_addr = (void *) (size_t) (LOAD_ADDRESS + (i - 1) * LOAD_INCREMENT);

I think we should be using MAP_FIXED in this mmap call, to make sure the mapping ends
up exactly at `load_addr`, and check the result to make sure it's not MAP_FAILED.

>        struct jit_code_entry *const entry = calloc (1, sizeof (*entry));
>  
> @@ -147,7 +150,7 @@ MAIN (int argc, char *argv[])
>  	  exit (1);
>  	}
>  
> -      update_locations (addr, i);
> +      update_name (addr, i);
>  
>        /* Link entry at the end of the list.  */
>        entry->symfile_addr = (const char *)addr;
> diff --git a/gdb/testsuite/lib/jit-elf-helpers.exp b/gdb/testsuite/lib/jit-elf-helpers.exp
> index f63694b8f5..cff47ec73c 100644
> --- a/gdb/testsuite/lib/jit-elf-helpers.exp
> +++ b/gdb/testsuite/lib/jit-elf-helpers.exp
> @@ -13,15 +13,25 @@
>  # You should have received a copy of the GNU General Public License
>  # along with this program.  If not, see <http://www.gnu.org/licenses/>.
>  
> +# Magic constants used to calculate a starting address when linking
> +# "jit" shared libraries. When loaded, will be mapped by jit-elf-main

Our standard is to use two spaces after periods in comments and other "prose".

Simon