Re: [gimplefe] Parsing __GIMPLE function body

[Richard Biener <richard dot guenther at gmail dot com>]

On Wed, Jun 1, 2016 at 9:19 AM, Prathamesh Kulkarni
<prathamesh.kulkarni@linaro.org> wrote:
> On 30 May 2016 at 20:45, Prasad Ghangal <prasad.ghangal@gmail.com> wrote:
>> Hi,
>>
>> As David suggested in his rtlfe patch,
>> this patch recognizes __GIMPLE keyword and switches to
>> c_parser_parse_gimple_body by providing -fgimple option.
>>
>>
>> diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
>> index 4568cf6..41a8f05 100644
>> --- a/gcc/c-family/c-common.c
>> +++ b/gcc/c-family/c-common.c
>> @@ -511,6 +511,7 @@ const struct c_common_resword c_common_reswords[] =
>>    { "__underlying_type", RID_UNDERLYING_TYPE, D_CXXONLY },
>>    { "__volatile",    RID_VOLATILE,    0 },
>>    { "__volatile__",    RID_VOLATILE,    0 },
>> +  { "__GIMPLE",        RID_GIMPLE,    0 },
>>    { "alignas",        RID_ALIGNAS,    D_CXXONLY | D_CXX11 | D_CXXWARN },
>>    { "alignof",        RID_ALIGNOF,    D_CXXONLY | D_CXX11 | D_CXXWARN },
>>    { "asm",        RID_ASM,    D_ASM },
>> diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h
>> index 0295532..23a401d 100644
>> --- a/gcc/c-family/c-common.h
>> +++ b/gcc/c-family/c-common.h
>> @@ -104,6 +104,9 @@ enum rid
>>    RID_DFLOAT32, RID_DFLOAT64, RID_DFLOAT128,
>>    RID_FRACT, RID_ACCUM, RID_AUTO_TYPE, RID_BUILTIN_CALL_WITH_STATIC_CHAIN,
>>
>> +  /* "__GIMPLE", for the GIMPLE-parsing extension to the C frontend. */
>> +  RID_GIMPLE,
>> +
>>    /* C11 */
>>    RID_ALIGNAS, RID_GENERIC,
>>
>> diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
>> index 918df16..8ab56af 100644
>> --- a/gcc/c-family/c.opt
>> +++ b/gcc/c-family/c.opt
>> @@ -200,6 +200,10 @@ F
>>  Driver C ObjC C++ ObjC++ Joined Separate MissingArgError(missing path
>> after %qs)
>>  -F <dir>    Add <dir> to the end of the main framework include path.
>>
>> +fgimple
>> +C Var(flag_gimple) Init(0)
>> +Enable parsing GIMPLE
>> +
>>  H
>>  C ObjC C++ ObjC++
>>  Print the name of header files as they are used.
>> diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
>> index 1cf4fb4..c5a4d3f 100644
>> --- a/gcc/c/c-parser.c
>> +++ b/gcc/c/c-parser.c
>> @@ -1396,6 +1396,7 @@ static bool c_parser_cilk_verify_simd (c_parser
>> *, enum pragma_context);
>>  static tree c_parser_array_notation (location_t, c_parser *, tree, tree);
>>  static tree c_parser_cilk_clause_vectorlength (c_parser *, tree, bool);
>>  static void c_parser_cilk_grainsize (c_parser *, bool *);
>> +static void c_parser_parse_gimple_body (c_parser *parser);
>>
>>  /* Parse a translation unit (C90 6.7, C99 6.9).
>>
>> @@ -1638,6 +1639,7 @@ c_parser_declaration_or_fndef (c_parser *parser,
>> bool fndef_ok,
>>    tree all_prefix_attrs;
>>    bool diagnosed_no_specs = false;
>>    location_t here = c_parser_peek_token (parser)->location;
>> +  bool gimple_body_p = false;
>>
>>    if (static_assert_ok
>>        && c_parser_next_token_is_keyword (parser, RID_STATIC_ASSERT))
>> @@ -1687,6 +1689,17 @@ c_parser_declaration_or_fndef (c_parser
>> *parser, bool fndef_ok,
>>        c_parser_skip_to_end_of_block_or_statement (parser);
>>        return;
>>      }
>> +
>> +  if (c_parser_next_token_is (parser, CPP_KEYWORD))
>> +    {
>> +      c_token *kw_token = c_parser_peek_token (parser);
>> +      if (kw_token->keyword == RID_GIMPLE)
>> +    {
>> +      gimple_body_p = true;
>> +      c_parser_consume_token (parser);
>> +    }
>> +    }
>> +
>>    finish_declspecs (specs);
>>    bool auto_type_p = specs->typespec_word == cts_auto_type;
>>    if (c_parser_next_token_is (parser, CPP_SEMICOLON))
>> @@ -2102,6 +2115,14 @@ c_parser_declaration_or_fndef (c_parser
>> *parser, bool fndef_ok,
>>                     oacc_routine_clauses, false, first, true);
>>        DECL_STRUCT_FUNCTION (current_function_decl)->function_start_locus
>>      = c_parser_peek_token (parser)->location;
>> +
>> +      if (gimple_body_p && flag_gimple)
>> +    {
>> +      c_parser_parse_gimple_body (parser);
>> +      finish_function ();
>> +      return;
>> +    }
>> +
>>        fnbody = c_parser_compound_statement (parser);
>>        if (flag_cilkplus && contains_array_notation_expr (fnbody))
>>      fnbody = expand_array_notation_exprs (fnbody);
>> @@ -2123,7 +2144,7 @@ c_parser_declaration_or_fndef (c_parser *parser,
>> bool fndef_ok,
>>        add_stmt (fnbody);
>>        finish_function ();
>>      }
>> -
>> +
>>        timevar_pop (tv);
>>        break;
>>      }
>> @@ -18055,4 +18076,23 @@ c_parser_array_notation (location_t loc,
>> c_parser *parser, tree initial_index,
>>    return value_tree;
>>  }
>>
>> +/* Parse the body of a function declaration marked with "__GIMPLE".  */
>> +
>> +void
>> +c_parser_parse_gimple_body (c_parser *parser)
>> +{
>> +  if (!c_parser_require (parser, CPP_OPEN_BRACE, "expected %<{%>"))
>> +    return;
>> +
>> +  location_t loc1 = c_parser_peek_token (parser)->location;
>> +  inform (loc1, "start of GIMPLE");
>> +
>> +  while (c_parser_next_token_is_not (parser, CPP_CLOSE_BRACE))
> Could this possibly go into infinite loop if '}' is not present in the source ?

You'd have to look into the source but I guess it will raise an error like
"EOF before expected }".

Richard.

> Thanks,
> Prathamesh
>> +    {
>> +    c_parser_consume_token (parser);
>> +    }
>> +
>> +  c_parser_consume_token (parser);
>> +}
>> +
>>  #include "gt-c-c-parser.h"
>>
>>
>>
>>
>> GIMPLE function body consists of GIMPLE statements. For parsing GIMPLE
>> function body, we need to populate gimple body with gimple statements
>> which will emit GIMPLE as it is.
>>
>> I would like to hear suggestions about how can I emit GIMPLE directly from FE.
>>
>>
>>
>> Thanks,
>> Prasad Ghangal