[fortran,patch] Wide characeters, main patch

[FX <fxcoudert at gmail dot com>]

Well, I said only the final patch was missing, but it's getting very  
long to make completely cleanly, because there are so many intrinsics  
to fully check. So, to ease review and allow you to review the patch  
while I work on the last missing intrinsics, here is the main part of  
the patch enabling full wide strings support. What it does:

  -- allow construction of wide char litterals: they're strings with  
the correct memory representation stored in it (code lifted from  
target-memory.h to do that correctly), and the correct wide char  
basetype
  -- modify front-end routines so that allocating and copying  
strings takes into account the existence of wide characters
  -- removing various restrictions on standard intrinsics, adapting  
code when needed and adding library functions to deal with wide chars
  -- check that all standard intrinsics that should only accept  
default character kinds do so; also, I decided that all GNU  
extensions would only deal with default character kinds, implemented  
these restrictions and documented them
  -- add conversion functions for the assignment of one character  
kind to a variable of another type; this currently does not error out  
at runtime (it wraps around with the semantics of unsigned integers),  
but we could make it do so later if deemed useful; the front-end  
framework to do so is inspired by the other conversions, but not  
integrated because the character conversion is allowed in different  
places (namely, only in assignment) (as a side note: I've tried at  
first to integrate it with other conversions, but it was rather a mess)
  -- fixed a few bits and odds here and there; the one-line change  
to get_array_ctor_var_strlen() is fixing a bug that could manifest  
itself with long strings in array constructors (longer than 255).


What it doesn't do, and what I will be working on from now on:

  -- some more intrinsics: CSHIFT, EOSHIFT, INDEX, {MIN,MAX} 
{LOC,VAL}, MERGE, MIN, MAX, MVBITS, NEW_LINE, REPEAT, SCAN, SIZEOF,  
TRANSFER, VERIFY (writing testcases, manually inspecting the  
generated code, fixing front-end and adding library functions where  
necessary; some notes: REPEAT only needs testcases, because I already  
fixed the front-end and manually tested; INDEX, MERGE, SCAN, VERIFY  
and TRANSFER should be straightforward)
  -- write testcases for a few things that could potentially behave  
unexpectedly: I'm currently thinking of allocatables, functions  
returning widechar strings, user-defined operators, one-character  
assignment (I already tested it manually and it works as expected),  
playing with modules

The patch comes as a full version in file wide_char_part6.diff. I've  
also broken it down into pieces for ease of reading, with their  
separate ChangeLog entries: front-end, library and testsuite. I also  
include a patch to the middle-end tree pretty-printer, which makes  
litteral widechar strings easier to read; I will not commit it with  
the rest, and will seek approval by middle-end maintainers later.

Patch bootstraps and regtestes fine on x86_64-linux (both -m32 and - 
m64), except for gfortran.dg/char_cast_1.f90 and gfortran.dg/ 
char_cast_2.f90; it's not a fundamental problem but the testcase is  
scanning its dump tree, which has changed with my modifications to  
gfc_trans_string_copy(); I'll modify it accordingly before  
committing. Comments welcome. OK to commit?

FX

--
François-Xavier Coudert
http://www.homepages.ucl.ac.uk/~uccafco/

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