How to customize GCC builtin search paths

How to customize GCC builtin search paths

[William Tambe]

How to customize GCC builtin search paths that it uses for %s in its
specs syntax ?

Re: How to customize GCC builtin search paths

[Jim Wilson]

On Thu, Apr 9, 2020 at 7:52 PM William Tambe via Gcc-help
<gcc-help@gcc.gnu.org> wrote:
> How to customize GCC builtin search paths that it uses for %s in its
> specs syntax ?

This is startfile_prefixes in gcc.c.

Jim

Re: How to customize GCC builtin search paths

[William Tambe]

On Fri, Apr 10, 2020 at 1:16 PM Jim Wilson <jimw@sifive.com> wrote:
>
> On Thu, Apr 9, 2020 at 7:52 PM William Tambe via Gcc-help
> <gcc-help@gcc.gnu.org> wrote:
> > How to customize GCC builtin search paths that it uses for %s in its
> > specs syntax ?
>
> This is startfile_prefixes in gcc.c.

I can hardly find examples on how to use startfile_prefixes. Currently
when running gcc as follow:
arch-elf-gcc -v test.c

I get the following excerpt showing how gcc looks for includes:

#include "..." search starts here:
#include <...> search starts here:
/opt/arch-toolchain/lib/gcc/arch-elf/9.2.0/include
/opt/arch-toolchain/lib/gcc/arch-elf/9.2.0/include-fixed
/opt/arch-toolchain/lib/gcc/arch-elf/9.2.0/../../../../arch-elf/include

However, I am looking to change how gcc looks for includes as follow:

#include "..." search starts here:
#include <...> search starts here:
/opt/arch-toolchain/lib/gcc/arch-elf/9.2.0/../../../../include
/opt/arch-toolchain/lib/gcc/arch-elf/9.2.0/../../../../arch-elf/include
/opt/arch-toolchain/lib/gcc/arch-elf/9.2.0/include
/opt/arch-toolchain/lib/gcc/arch-elf/9.2.0/include-fixed

Any idea what piece of code populate the list of paths where to look
for includes ?

>
> Jim

Re: How to customize GCC builtin search paths

[Jim Wilson]

On Sun, Apr 12, 2020 at 9:06 AM William Tambe <tambewilliam@gmail.com> wrote:
> I can hardly find examples on how to use startfile_prefixes. Currently
> when running gcc as follow:
> arch-elf-gcc -v test.c
>
> I get the following excerpt showing how gcc looks for includes:

You have the source code.  You can find a lot of info by using grep to
search for obvious things, like /usr/include for instance, and then
follow the code to see where it takes you.

But include files are handled differently than startfiles.  This is a
different question than the previous one.  See cppdefault.c.  It isn't
a good idea to try to change this.  Stuff will break.  See also
include_prefixes in gcc.c.

Jim

Re: How to customize GCC builtin search paths

[Jonathan Wakely]

On Mon, 13 Apr 2020 at 21:46, Jim Wilson wrote:
>
> On Sun, Apr 12, 2020 at 9:06 AM William Tambe <tambewilliam@gmail.com> wrote:
> > I can hardly find examples on how to use startfile_prefixes. Currently
> > when running gcc as follow:
> > arch-elf-gcc -v test.c
> >
> > I get the following excerpt showing how gcc looks for includes:
>
> You have the source code.  You can find a lot of info by using grep to
> search for obvious things, like /usr/include for instance, and then
> follow the code to see where it takes you.

Right, the following commands were all I needed to answer your
question about thread model:

git grep 'Thread model' gcc
git grep thrmod gcc
git grep thread_model gcc
gvim gcc/configure.ac
git grep thread_file gcc
gvim gcc/config.gcc

You could have done that yourself pretty easily, and probably found
the answer quicker than waiting for a reply from the mailing list.