Add "__RTL" to cc1 (v2)

On Wed, 2016-10-05 at 16:09 +0000, Joseph Myers wrote:
> On Wed, 5 Oct 2016, David Malcolm wrote:
> 
> > @@ -1752,6 +1759,35 @@ 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_RTL)
> 
> if (c_parser_next_token_is_keyword (parser, RID_RTL))
> 
> You're missing an update to the comment above this function to show
> what
> the new syntax is.

Thanks.  Here's an updated version of the patch which fixes that,
along with some other fixes:
* Use c_parser_next_token_is_keyword.
* Removed a stray "FIXME".
* Removed some debug code.
* Add more comments
* Fixed a typo in the ChangeLog ("__RID" -> "__RTL")

Blurb from original version:

This patch implements Richi's idea of having a custom __RTL marker
in C function definitions, to indicate that the body of the function
is to be parsed as RTL, rather than C:

int __RTL test_fn_1 (int i)
{
 (function "times_two"
   (insn-chain
     (note 1 0 4 (nil) NOTE_INSN_DELETED)
     ;; etc
   ) ;; insn-chain
   (crtl
     (return_rtx
       (reg/i:SI 0 ax)
     ) ;; return_rtx
   ) ;; crtl
  ) ;; function
}

This allows for decls and types to be declared in C, and to use
the function decl from the C frontend.

I added support for running a single pass by giving __RTL an optional
parameter (the name of the pass).  For example:

int __RTL ("rtl-dfinit") test_fn_2 (int i)
{
 (function "times_two"
   (insn-chain
     (note 1 0 4 (nil) NOTE_INSN_DELETED)
     ;; etc
   ) ;; insn-chain
   (crtl
     (return_rtx
       (reg/i:SI 0 ax)
     ) ;; return_rtx
   ) ;; crtl
  ) ;; function
}

The top-level "function" directive is rather redundant; perhaps it should
be omitted?  This would give e.g.:

int __RTL ("rtl-dfinit") test_fn_3 (int i)
{
   (insn-chain
     (note 1 0 4 (nil) NOTE_INSN_DELETED)
     ;; etc
   ) ;; insn-chain
   (crtl
     (return_rtx
       (reg/i:SI 0 ax)
     ) ;; return_rtx
   ) ;; crtl
}

(Though maybe we want to keep it as a place to hold top-level metadata)

gcc/c-family/ChangeLog:
	* c-common.c (c_common_reswords): Add "__RTL".
	* c-common.h (enum rid): Add RID_RTL.

gcc/c/ChangeLog:
	* c-parser.c: Include "read-rtl-function.h" and
	"run-one-rtl-pass.h".
	(c_parser_declaration_or_fndef): In the "GNU extensions" part of
	the leading comment, add an alternate production for
	"function-definition", along with new "rtl-body-specifier" and
	"rtl-body-pass-specifier" productions.  Handle "__RTL" by calling
	c_parser_parse_rtl_body.  Convert a timevar_push/pop pair
	to an auto_timevar, to cope with early exit.
	(c_parser_parse_rtl_body): New function.

gcc/ChangeLog:
	* read-md.c (base_rtx_reader::read_char): Support filtering
	the input to a subset of line numbers.
	(base_rtx_reader::base_rtx_reader): Initialize fields
	m_first_line and m_last_line.
	(base_rtx_reader::read_file_fragment): New method.
	* read-md.h (base_rtx_reader::read_file_fragment): New decl.
	(base_rtx_reader::m_first_line): New field.
	(base_rtx_reader::m_last_line): New field.
	* read-rtl-function.c (function_reader::create_function): Only create
	cfun if it doesn't already exist.
	(read_rtl_function_body_from_file_range): New function.
	* read-rtl-function.h (read_rtl_function_body_from_file_range):
	New decl.

gcc/testsuite/ChangeLog:
	* rtl.dg/rtl.exp: Add .c files below rtl.dg to "tests".
	* rtl.dg/x86_64/different-structs.c: New file.
	* rtl.dg/x86_64/test-return-const.c.after-expand.c: New file.
	* rtl.dg/x86_64/test-return-const.c.before-fwprop.c: New file.
	* rtl.dg/x86_64/test-rtl.c: New file.
	* rtl.dg/x86_64/times-two.c.after-expand.c: New file.
	* rtl.dg/x86_64/times-two.c.before-df.c: New file.
---
 gcc/c-family/c-common.c                            |   1 +
 gcc/c-family/c-common.h                            |   3 +
 gcc/c/c-parser.c                                   | 113 ++++++++++++++++++++-
 gcc/read-md.c                                      |  34 ++++++-
 gcc/read-md.h                                      |   7 ++
 gcc/read-rtl-function.c                            |  78 ++++++++++----
 gcc/read-rtl-function.h                            |   3 +
 gcc/testsuite/rtl.dg/rtl.exp                       |   4 +-
 gcc/testsuite/rtl.dg/x86_64/different-structs.c    | 101 ++++++++++++++++++
 .../x86_64/test-return-const.c.after-expand.c      |  23 +++++
 .../x86_64/test-return-const.c.before-fwprop.c     |  27 +++++
 gcc/testsuite/rtl.dg/x86_64/test-rtl.c             |  95 +++++++++++++++++
 .../rtl.dg/x86_64/times-two.c.after-expand.c       |  40 ++++++++
 .../rtl.dg/x86_64/times-two.c.before-df.c          |  57 +++++++++++
 14 files changed, 565 insertions(+), 21 deletions(-)
 create mode 100644 gcc/testsuite/rtl.dg/x86_64/different-structs.c
 create mode 100644 gcc/testsuite/rtl.dg/x86_64/test-return-const.c.after-expand.c
 create mode 100644 gcc/testsuite/rtl.dg/x86_64/test-return-const.c.before-fwprop.c
 create mode 100644 gcc/testsuite/rtl.dg/x86_64/test-rtl.c
 create mode 100644 gcc/testsuite/rtl.dg/x86_64/times-two.c.after-expand.c
 create mode 100644 gcc/testsuite/rtl.dg/x86_64/times-two.c.before-df.c

Add "__RTL" to cc1 (v2)

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