Re: [Tinycc-devel] tcc -static is broken

[grischka]

Ali Gholami Rudi wrote:
> Hi,
>
> Currently static linking is broken (tried linking with dietlibc).
> I think the problem is tcc uses the GOT table but since it is
> linked statically, dynamic linker no longer fills it.  I'm not sure
> if this is the correct way of fixing it; I've attached a patch to
> fill the GOT after linking (only for x86-64).
>
>         Ali

Please push patches on our "mob" branch:
  http://repo.or.cz/w/tinycc.git

Thus it is also easier for other people to test and give you
feedback.

Thanks,
--- grischka

> From: Ali Gholami Rudi <address@hidden>
> Subject: [PATCH] fill got table for static linking
>
>
>  libtcc.c |    9 +++++++++
>  tcc.h    |    1 +
>  tccelf.c |   44 ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 54 insertions(+), 0 deletions(-)
>
> diff --git a/libtcc.c b/libtcc.c
> index 520abfd..7fb245d 100644
> --- a/libtcc.c
> +++ b/libtcc.c
> @@ -372,6 +372,15 @@ ST_FUNC void *section_ptr_add(Section *sec, unsigned long 
> size)
>      return sec->data + offset;
>  }
>  
> +/* reserve at least 'size' bytes from section start */
> +ST_FUNC void section_reserve(Section *sec, unsigned long size)
> +{
> +    if (size > sec->data_allocated)
> +        section_realloc(sec, size);
> +    if (size > sec->data_offset)
> +        sec->data_offset = size;
> +}
> +
>  /* return a reference to a section, and create it if it does not
>     exists */
>  ST_FUNC Section *find_section(TCCState *s1, const char *name)
> diff --git a/tcc.h b/tcc.h
> index 3481f64..4b8111c 100644
> --- a/tcc.h
> +++ b/tcc.h
> @@ -891,6 +891,7 @@ ST_FUNC void add_char(CString *cstr, int c);
>  ST_FUNC Section *new_section(TCCState *s1, const char *name, int sh_type, int 
> sh_flags);
>  ST_FUNC void section_realloc(Section *sec, unsigned long new_size);
>  ST_FUNC void *section_ptr_add(Section *sec, unsigned long size);
> +ST_FUNC void section_reserve(Section *sec, unsigned long size);
>  ST_FUNC Section *find_section(TCCState *s1, const char *name);
>  
>  ST_FUNC void put_extern_sym2(Sym *sym, Section *section, unsigned long value, unsigned long size, int can_add_underscore);
> diff --git a/tccelf.c b/tccelf.c
> index a5385b1..2323a6b 100644
> --- a/tccelf.c
> +++ b/tccelf.c
> @@ -1361,6 +1361,48 @@ void patch_dynsym_undef(TCCState *s1, Section *s)
>  #define        EXTRA_RELITEMS  9
>  #endif
>  
> +ST_FUNC void fill_got_entry(TCCState *s1, ElfW_Rel *rel)
> +{
> +       int sym_index = ELFW(R_SYM) (rel->r_info);
> +       ElfW(Sym) *sym = &((ElfW(Sym) *) symtab_section->data)[sym_index];
> +       unsigned long offset;
> +
> +       if (sym_index >= s1->nb_got_offsets)
> +               return;
> +       offset = s1->got_offsets[sym_index];
> +       section_reserve(s1->got, offset + PTR_SIZE);
> +       /* only works for x86-64 */
> +       put32(s1->got->data + offset, sym->st_value >> 32);
> +       put32(s1->got->data + offset, sym->st_value & 0xffffffff);
> +}
> +
> +ST_FUNC void fill_got(TCCState *s1)
> +{
> +       Section *s;
> +       ElfW_Rel *rel, *rel_end;
> +       int i;
> +
> +       for(i = 1; i < s1->nb_sections; i++) {
> +               s = s1->sections[i];
> +               if (s->sh_type != SHT_RELX)
> +                       continue;
> +               /* no need to handle got relocations */
> +               if (s->link != symtab_section)
> +                       continue;
> +               rel_end = (ElfW_Rel *) (s->data + s->data_offset);
> +               for(rel = (ElfW_Rel *) s->data; rel < rel_end; rel++) {
> +                       switch (ELFW(R_TYPE) (rel->r_info)) {
> +                       case R_X86_64_GOT32:
> +                       case R_X86_64_GOTPCREL:
> +                       case R_X86_64_PLT32:
> +                               fill_got_entry(s1, rel);
> +                               break;
> +                       }
> +               }
> +       }
> +}
> +
> +
>  /* output an ELF file */
>  /* XXX: suppress unneeded sections */
>  static int elf_output_file(TCCState *s1, const char *filename)
> @@ -1977,6 +2019,8 @@ static int elf_output_file(TCCState *s1, const char 
> *filename)
>          else
>              ehdr.e_entry = text_section->sh_addr; /* XXX: is it correct ? */
>      }
> +    if (file_type == TCC_OUTPUT_EXE && s1->static_link)
> +        fill_got(s1);
>  
>      /* write elf file */
>      if (file_type == TCC_OUTPUT_OBJ)