On Thu, Apr 18, 2024 at 6:12 AM Peter Damianov <peter0...@disroot.org> wrote:
>
> This commit adds a new option to the driver that truncates one file after
> linking.
>
> Tested likeso:
>
> $ gcc hello.c -c
> $ du -h hello.o
> 4.0K hello.o
> $ gcc hello.o -truncate hello
> $ ./a.out
> Hello world
> $ du -h hello.o
> $ 0 hello.o
I suppose it should have been
$ gcc hello.o -truncate hello.o
in the example.
> $ gcc hello.o -truncate
> gcc: error: missing filename after '-truncate'
>
> The motivation for adding this is PR110710. It is used by lto-wrapper to
> truncate files in a shell-independent manner.
This looks good to me.
Thanks,
Richard.
> Signed-off-by: Peter Damianov <peter0...@disroot.org>
> ---
> v2: moved truncation to driver::final_actions
> v2: moved handling of OPT_truncate to be in alphabetic order
>
> gcc/common.opt | 6 ++++++
> gcc/gcc.cc | 13 +++++++++++++
> 2 files changed, 19 insertions(+)
>
> diff --git a/gcc/common.opt b/gcc/common.opt
> index ad348844775..40cab3cb36a 100644
> --- a/gcc/common.opt
> +++ b/gcc/common.opt
> @@ -422,6 +422,12 @@ Display target specific command line options (including
> assembler and linker opt
> -time
> Driver Alias(time)
>
> +;; Truncate the file specified after linking.
> +;; This option is used by lto-wrapper to reduce the peak disk-usage when
> +;; linking with many .LTRANS units.
> +truncate
> +Driver Separate Undocumented MissingArgError(missing filename after %qs)
> +
> -verbose
> Driver Alias(v)
>
> diff --git a/gcc/gcc.cc b/gcc/gcc.cc
> index 728332b8153..b4169bbd3be 100644
> --- a/gcc/gcc.cc
> +++ b/gcc/gcc.cc
> @@ -2138,6 +2138,10 @@ static int have_E = 0;
> /* Pointer to output file name passed in with -o. */
> static const char *output_file = 0;
>
> +/* Pointer to input file name passed in with -truncate.
> + This file should be truncated after linking. */
> +static const char *totruncate_file = 0;
> +
> /* This is the list of suffixes and codes (%g/%u/%U/%j) and the associated
> temp file. If the HOST_BIT_BUCKET is used for %j, no entry is made for
> it here. */
> @@ -4538,6 +4542,10 @@ driver_handle_option (struct gcc_options *opts,
> do_save = false;
> break;
>
> + case OPT_truncate:
> + totruncate_file = arg;
> + break;
> +
> case OPT____:
> /* "-###"
> This is similar to -v except that there is no execution
> @@ -9286,6 +9294,11 @@ driver::final_actions () const
> delete_failure_queue ();
> delete_temp_files ();
>
> + if (totruncate_file != NULL && !seen_error ())
> + /* Truncate file specified by -truncate.
> + Used by lto-wrapper to reduce temporary disk-space usage. */
> + truncate(totruncate_file, 0);
> +
> if (print_help_list)
> {
> printf (("\nFor bug reporting instructions, please see:\n"));
> --
> 2.39.2
>
