Re: [PATCH] WebAssembly: Correct an `index' global shadowing error for pre-4.8 GCC

[Pip Cet <pipcet at gmail dot com>]

Hello Maciej,
again, thank you for looking at this code and testing it. The change
also looks obviously correct to me.

Pip

On Sat, Feb 3, 2018 at 3:15 PM, Maciej W. Rozycki <macro@mips.com> wrote:
> Remove `-Wshadow' compilation errors:
>
> cc1: warnings being treated as errors
> .../bfd/wasm-module.c: In function 'wasm_scan_name_function_section':
> .../bfd/wasm-module.c:312: error: declaration of 'index' shadows a global declaration
> /usr/include/string.h:303: error: shadowed declaration is here
> .../bfd/wasm-module.c: In function 'wasm_register_section':
> .../bfd/wasm-module.c:494: error: declaration of 'index' shadows a global declaration
> /usr/include/string.h:303: error: shadowed declaration is here
> .../bfd/wasm-module.c: In function 'wasm_compute_custom_section_file_position':
> .../bfd/wasm-module.c:523: error: declaration of 'index' shadows a global declaration
> /usr/include/string.h:303: error: shadowed declaration is here
>
> and:
>
> cc1: warnings being treated as errors
> .../opcodes/wasm32-dis.c: In function 'print_insn_wasm32':
> .../opcodes/wasm32-dis.c:272: error: declaration of 'index' shadows a global declaration
> /usr/include/string.h:303: error: shadowed declaration is here
> make[4]: *** [wasm32-dis.lo] Error 1
>
> which for versions of GCC before 4.8 prevent support for the WebAssembly
> target from being built.  See also GCC PR c/53066.
>
>         bfd/
>         * wasm-module.c (wasm_scan_name_function_section): Rename
>         `index' local variable to `idx'.
>
>         opcodes/
>         * wasm32-dis.c (print_insn_wasm32): Rename `index' local
>         variable to
> ---
> Hi,
>
>  This has popped up in routine cross-target testing for an unrelated
> change and should be obvious.  OK to apply?
>
>   Maciej
> ---
>  bfd/wasm-module.c    |   18 +++++++++---------
>  opcodes/wasm32-dis.c |    6 +++---
>  2 files changed, 12 insertions(+), 12 deletions(-)
>
> binutils-wasm32-index-shadow.diff
> Index: binutils/bfd/wasm-module.c
> ===================================================================
> --- binutils.orig/bfd/wasm-module.c     2018-02-02 05:34:05.217268819 +0000
> +++ binutils/bfd/wasm-module.c  2018-02-02 05:34:41.869388049 +0000
> @@ -309,12 +309,12 @@ wasm_scan_name_function_section (bfd *ab
>
>    for (symcount = 0; p < end && symcount < tdata->symcount; symcount++)
>      {
> -      bfd_vma index;
> +      bfd_vma idx;
>        bfd_vma len;
>        char *name;
>        asymbol *sym;
>
> -      READ_LEB128 (index, p, end);
> +      READ_LEB128 (idx, p, end);
>        READ_LEB128 (len, p, end);
>
>        if (p + len < p || p + len > end)
> @@ -330,7 +330,7 @@ wasm_scan_name_function_section (bfd *ab
>        sym = &symbols[symcount];
>        sym->the_bfd = abfd;
>        sym->name = name;
> -      sym->value = index;
> +      sym->value = idx;
>        sym->flags = BSF_GLOBAL | BSF_FUNCTION;
>        sym->section = space_function_index;
>        sym->udata.p = NULL;
> @@ -491,12 +491,12 @@ wasm_register_section (bfd *abfd ATTRIBU
>                        void *fsarg)
>  {
>    sec_ptr *numbered_sections = fsarg;
> -  int index = wasm_section_name_to_code (asect->name);
> +  int idx = wasm_section_name_to_code (asect->name);
>
> -  if (index == 0)
> +  if (idx == 0)
>      return;
>
> -  numbered_sections[index] = asect;
> +  numbered_sections[idx] = asect;
>  }
>
>  struct compute_section_arg
> @@ -520,14 +520,14 @@ wasm_compute_custom_section_file_positio
>                                            void *fsarg)
>  {
>    struct compute_section_arg *fs = fsarg;
> -  int index;
> +  int idx;
>
>    if (fs->failed)
>      return;
>
> -  index = wasm_section_name_to_code (asect->name);
> +  idx = wasm_section_name_to_code (asect->name);
>
> -  if (index != 0)
> +  if (idx != 0)
>      return;
>
>    if (CONST_STRNEQ (asect->name, WASM_SECTION_PREFIX))
> Index: binutils/opcodes/wasm32-dis.c
> ===================================================================
> --- binutils.orig/opcodes/wasm32-dis.c  2018-01-28 00:50:52.000000000 +0000
> +++ binutils/opcodes/wasm32-dis.c       2018-02-02 05:36:53.262294076 +0000
> @@ -269,7 +269,7 @@ print_insn_wasm32 (bfd_vma pc, struct di
>    long flags = 0;
>    long offset = 0;
>    long depth = 0;
> -  long index = 0;
> +  long function_index = 0;
>    long target_count = 0;
>    long block_type = 0;
>    int len = 1;
> @@ -416,14 +416,14 @@ print_insn_wasm32 (bfd_vma pc, struct di
>            break;
>
>          case wasm_call:
> -          index = wasm_read_leb128
> +          function_index = wasm_read_leb128
>              (pc + len, info, &error, &bytes_read, FALSE);
>            if (error)
>              return -1;
>            len += bytes_read;
>            prin (stream, " ");
>            private_data->section_prefix = ".space.function_index";
> -          (*info->print_address_func) ((bfd_vma) index, info);
> +          (*info->print_address_func) ((bfd_vma) function_index, info);
>            private_data->section_prefix = NULL;
>            break;
>