V3 PATCH: Document dg.exp interface

[Gabriel Dos Reis <Gabriel dot Dos-Reis at cmla dot ens-cachan dot fr>]

I added the below to ease the job of people writing testsuite for V3. 
Benjamin, please check if you want more info (it's late so maybe I
won't respond promptly but I'll try to address your request as soon as
possible).

Not bootstrapped.

-- Gaby

2001-04-12  Gabriel Dos Reis  <gdr@codesourcery.com>

	* testsuite/README: Add DejaGnu specific documentation.

Index: testsuite/README
===================================================================
RCS file: /cvs/gcc/egcs/libstdc++-v3/testsuite/README,v
retrieving revision 1.3
diff -p -r1.3 README
*** README	2001/01/28 15:13:08	1.3
--- README	2001/04/11 23:35:34
***************
*** 1,12 ****
! We're in the process of converting the existing testsuite machinery to
  use the new style DejaGnu framework.  Eventually, we'll abandon
! ../mkcheck.in in favor of this new testsuite framework.  
  
!   Basically, a testcase contains dg-keywords (see dg.exp) indicating
  what to do and what kinds of behaviour are to be expected.  New
! testcases should be written with the new style DejaGnu framework in mind.
  
!   The V3 testing framework supports additional keywords for the purpose
  of easing the job of writing testcases.  All V3-keywords are of the
  form @xxx@.  Currently supported keywords include:
  
--- 1,94 ----
!   We're in the process of converting the existing testsuite machinery to 
  use the new style DejaGnu framework.  Eventually, we'll abandon
! ../mkcheck.in in favor of this new testsuite framework. 
  
! Basically, a testcase contains dg-keywords (see dg.exp) indicating
  what to do and what kinds of behaviour are to be expected.  New
! testcases should be written with the new style DejaGnu framework in
! mind.
  
! To ease transition, here is the list of dg-keyword documentation
! lifted from dg.exp -- eventuaklly we should improve DejaGnu
! documentation, but getting checkin account currently demands Pyrrhic
! effort. 
! 
! # The currently supported options are:
! #
! # dg-prms-id N
! #	set prms_id to N
! #
! # dg-options "options ..." [{ target selector }]
! #	specify special options to pass to the tool (eg: compiler)
! #
! # dg-do do-what-keyword [{ target/xfail selector }]
! #	`do-what-keyword' is tool specific and is passed unchanged to
! #	${tool}-dg-test.  An example is gcc where `keyword' can be any of:
! #	preprocess|compile|assemble|link|run
! #	and will do one of: produce a .i, produce a .s, produce a .o,
! #	produce an a.out, or produce an a.out and run it (the default is
! #	compile).
! #
! # dg-error regexp comment [{ target/xfail selector } [{.|0|linenum}]]
! #	indicate an error message <regexp> is expected on this line
! #	(the test fails if it doesn't occur)
! #	Linenum=0 for general tool messages (eg: -V arg missing).
! #	"." means the current line.
! #
! # dg-warning regexp comment [{ target/xfail selector } [{.|0|linenum}]]
! #	indicate a warning message <regexp> is expected on this line
! #	(the test fails if it doesn't occur)
! #
! # dg-bogus regexp comment [{ target/xfail selector } [{.|0|linenum}]]
! #	indicate a bogus error message <regexp> use to occur here
! #	(the test fails if it does occur)
! #
! # dg-build regexp comment [{ target/xfail selector }]
! #	indicate the build use to fail for some reason
! #	(errors covered here include bad assembler generated, tool crashes,
! #	and link failures)
! #	(the test fails if it does occur)
! #
! # dg-excess-errors comment [{ target/xfail selector }]
! #	indicate excess errors are expected (any line)
! #	(this should only be used sparingly and temporarily)
! #
! # dg-output regexp [{ target selector }]
! #	indicate the expected output of the program is <regexp>
! #	(there may be multiple occurrences of this, they are concatenated)
! #
! # dg-final { tcl code }
! #	add some tcl code to be run at the end
! #	(there may be multiple occurrences of this, they are concatenated)
! #	(unbalanced braces must be \-escaped)
! #
! # "{ target selector }" is a list of expressions that determine whether the
! # test succeeds or fails for a particular target, or in some cases whether the
! # option applies for a particular target.  If the case of `dg-do' it specifies
! # whether the testcase is even attempted on the specified target.
! #
! # The target selector is always optional.  The format is one of:
! #
! # { xfail *-*-* ... } - the test is expected to fail for the given targets
! # { target *-*-* ... } - the option only applies to the given targets
! #
! # At least one target must be specified, use *-*-* for "all targets".
! # At present it is not possible to specify both `xfail' and `target'.
! # "native" may be used in place of "*-*-*".
! #
! # Example:
! #
! #       [ ... some complicated code ... ]
! #	return a; /* { dg-build "fatal" "ran out of spill regs" { xfail i386-*-* } } */
! #
! # In this example, the compiler use to crash on the "return a;" for some
! # target and that it still does crash on i386-*-*.  Admittedly, this is a
! # contrived example.
! #
! # ??? It might be possible to add additional optional arguments by having
! # something like: { dg-error ".*syntax.*" "syntax error" { { foo 1 } ... } }
! 
! 
! The V3 testing framework supports additional keywords for the purpose
  of easing the job of writing testcases.  All V3-keywords are of the
  form @xxx@.  Currently supported keywords include: