[Bug lto/55466] [4.8 Regression] Revision 191466 destroyed DWARF debug info

["hjl.tools at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55466

--- Comment #10 from H.J. Lu <hjl.tools at gmail dot com> 2012-12-07 18:49:10 UTC ---
(In reply to comment #7)
> This patch:
> 
> diff --git a/gcc/lto-symtab.c b/gcc/lto-symtab.c
> index 0b0cdac..295fd37 100644
> --- a/gcc/lto-symtab.c
> +++ b/gcc/lto-symtab.c
> @@ -443,10 +443,6 @@ lto_symtab_merge_decls_1 (symtab_node first)
> 
>    symtab_prevail_in_asm_name_hash (prevailing);
> 
> -  /* Record the prevailing variable.  */
> -  if (TREE_CODE (prevailing->symbol.decl) == VAR_DECL)
> -    vec_safe_push (lto_global_var_decls, prevailing->symbol.decl);
> -
>    /* Diagnose mismatched objects.  */
>    for (e = prevailing->symbol.next_sharing_asm_name;
>         e; e = e->symbol.next_sharing_asm_name)
> diff --git a/gcc/lto/lto.c b/gcc/lto/lto.c
> index 376af85..177fbfc 100644
> --- a/gcc/lto/lto.c
> +++ b/gcc/lto/lto.c
> @@ -2910,6 +2910,7 @@ read_cgraph_and_symbols (unsigned nfiles, const char
> **fnames)
>    struct cgraph_node *node;
>    int count = 0;
>    struct lto_file_decl_data **decl_data;
> +  struct varpool_node *vnode;
> 
>    init_cgraph ();
> 
> @@ -3088,6 +3089,10 @@ read_cgraph_and_symbols (unsigned nfiles, const char
> **fnames)
> 
>    timevar_pop (TV_IPA_LTO_CGRAPH_MERGE);
> 
> +  /* Record the global variables.  */
> +  FOR_EACH_DEFINED_VARIABLE (vnode)
> +    vec_safe_push (lto_global_var_decls, vnode->symbol.decl);
> +
>    timevar_push (TV_IPA_LTO_DECL_INIT_IO);
> 
>    /* Indicate that the cgraph is built and ready.  */
> 
> or
> 
> diff --git a/gcc/lto-symtab.c b/gcc/lto-symtab.c
> index 0b0cdac..295fd37 100644
> --- a/gcc/lto-symtab.c
> +++ b/gcc/lto-symtab.c
> @@ -443,10 +443,6 @@ lto_symtab_merge_decls_1 (symtab_node first)
> 
>    symtab_prevail_in_asm_name_hash (prevailing);
> 
> -  /* Record the prevailing variable.  */
> -  if (TREE_CODE (prevailing->symbol.decl) == VAR_DECL)
> -    vec_safe_push (lto_global_var_decls, prevailing->symbol.decl);
> -
>    /* Diagnose mismatched objects.  */
>    for (e = prevailing->symbol.next_sharing_asm_name;
>         e; e = e->symbol.next_sharing_asm_name)
> diff --git a/gcc/lto/lto.c b/gcc/lto/lto.c
> index 376af85..c7e1100 100644
> --- a/gcc/lto/lto.c
> +++ b/gcc/lto/lto.c
> @@ -3373,6 +3373,8 @@ lto_main (void)
> 
>    if (!seen_error ())
>      {
> +      struct varpool_node *vnode;
> +
>        /* If WPA is enabled analyze the whole call graph and create an
>       optimization plan.  Otherwise, read in all the function
>       bodies and continue with optimization.  */
> @@ -3398,6 +3400,10 @@ lto_main (void)
>        if (flag_lto_report)
>          print_lto_report_1 ();
>      }
> +
> +      /* Record the global variables.  */
> +      FOR_EACH_DEFINED_VARIABLE (vnode)
> +    vec_safe_push (lto_global_var_decls, vnode->symbol.decl);
>      }
> 
>    /* Here we make LTO pretend to be a parser.  */
> 
> seem to work.

It doesn't work.  When gcc is configured with

--enable-languages=c,c++,fortran,java,lto,objc,obj-c++,go, I got

lto1: internal compiler error: in add_AT_specification, at dwarf2out.c:3985
0x629ad9 add_AT_specification
        /export/gnu/import/git/gcc/gcc/dwarf2out.c:3985
0x64dabb gen_variable_die
        /export/gnu/import/git/gcc/gcc/dwarf2out.c:18327
0x65336b gen_decl_die
        /export/gnu/import/git/gcc/gcc/dwarf2out.c:20033
0x653fcd dwarf2out_decl(tree_node*)
        /export/gnu/import/git/gcc/gcc/dwarf2out.c:20348
0x6535f9 dwarf2out_global_decl
        /export/gnu/import/git/gcc/gcc/dwarf2out.c:20083
0x997703 emit_debug_global_declarations(tree_node**, int)
        /export/gnu/import/git/gcc/gcc/toplev.c:530
0x521aaa lto_write_globals
        /export/gnu/import/git/gcc/gcc/lto/lto-lang.c:1067
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.
make[6]: *** [/tmp/cc3yYR7d.ltrans4.ltrans.o] Error 1
lto-wrapper: make returned 2 exit status
lto-wrapper: make returned 2 exit status
/usr/local/x86_64-unknown-linux-gnu/bin/ld: lto-wrapper failed
collect2: error: ld returned 1 exit status
make[5]: *** [go1] Error 1