> Good hint. I added hash based on object file name (I don't want to handle
> proper string escaping) and -frandom-seed.
>
> What do you think about the patch?
Sorry for taking so long - I remember I was sending reply earlier but it
seems I only wrote it and never sent.
> Thanks,
> Martin
> From 372d2944571906932fd1419bfc51a949d67b857e Mon Sep 17 00:00:00 2001
> From: Martin Liska <mli...@suse.cz>
> Date: Fri, 21 May 2021 10:25:49 +0200
> Subject: [PATCH] LTO: add lto_priv suffixfor LTO_LINKER_OUTPUT_NOLTOREL.
>
> gcc/lto/ChangeLog:
>
> * lto-partition.c (privatize_symbol_name_1): Add random suffix
> based on hash of the object file and -frandom-seed.
> ---
> gcc/lto/lto-partition.c | 21 ++++++++++++++++++---
> 1 file changed, 18 insertions(+), 3 deletions(-)
>
> diff --git a/gcc/lto/lto-partition.c b/gcc/lto/lto-partition.c
> index 15761ac9eb5..fef48c869a2 100644
> --- a/gcc/lto/lto-partition.c
> +++ b/gcc/lto/lto-partition.c
> @@ -35,6 +35,7 @@ along with GCC; see the file COPYING3. If not see
> #include "ipa-fnsummary.h"
> #include "lto-partition.h"
> #include "sreal.h"
> +#include "toplev.h"
>
> vec<ltrans_partition> ltrans_partitions;
>
> @@ -941,9 +942,23 @@ privatize_symbol_name_1 (symtab_node *node, tree decl)
>
> name = maybe_rewrite_identifier (name);
> unsigned &clone_number = lto_clone_numbers->get_or_insert (name);
> - symtab->change_decl_assembler_name (decl,
> - clone_function_name (
> - name, "lto_priv", clone_number));
> +
> + char *suffix = NULL;
> + if (flag_lto_linker_output == LTO_LINKER_OUTPUT_NOLTOREL)
> + {
> + hashval_t fnhash = 0;
> + if (node->lto_file_data != NULL)
> + fnhash = htab_hash_string (node->lto_file_data->file_name);
> + suffix = XNEWVEC (char, 128);
> + char sep = symbol_table::symbol_suffix_separator ();
> + sprintf (suffix, "lto_priv%c%u%c%" PRIu64, sep, fnhash, sep,
> + (unsigned HOST_WIDE_INT)get_random_seed (false));
We have get_file_function_name which does similar work but also working
without random seeds. Perhaps we can reuse it here: use
get_file_function_name once and use it as prefix or compute hash from
it.
The logic to get unique symbol name is not completely easy and it would
be better to not duplciate it. Patch is OK with that change
(and indeed it is bugfix - even if it is relatively little used partial
linking of LTO objects into non-LTO should be supported and working).
Honza
> + }
> +
> + tree clone
> + = clone_function_name (name, suffix ? suffix : "lto_priv", clone_number);
> + symtab->change_decl_assembler_name (decl, clone);
> + free (suffix);
> clone_number++;
>
> if (node->lto_file_data)
> --
> 2.31.1
>
