Re: [PATCH] rust: build failure after NON_DEPENDENT_EXPR removal [PR111899]

[Jason Merrill]

On 10/23/23 05:10, Thomas Schwinge wrote:

Hi Patrick!

On 2023-10-20T13:36:30-0400, Patrick Palka  wrote:

Built on x86_64-pc-linux-gnu, pushed to trunk as obvious (hopefully).

-- >8 --

This patch removes stray NON_DEPENDENT_EXPR checks following the removal
of this tree code from the C++ FE.  (Since this restores the build I
supppose it means the Rust FE never creates NON_DEPENDENT_EXPR trees in
the first place, so no further analysis is needed.)


ACK, thanks!


For context: indeed, a non-trivial amount of C++ front end 'constexpr'
code was copied into the Rust front end, for implementing related Rust
functionality, mostly as part of the 2022 GSoC project
"Support for Constant Folding in Rust Frontend" (Faisal Abbas),
.

Yes, this should eventually be cleaned up (and merged with the original
C++ front end code, as much as feasible -- which I don't know whether or
to which extent it is).


It would be nice to move a lot of the constexpr code into the 
middle-end, but I expect that would be a significant project.


Jason

Re: [PATCH v2 2/4] libgrust: Add libproc_macro and build system

[Jason Merrill]

On 12/15/23 04:53, Thomas Schwinge wrote:

Hi Jason!

I think you usually deal with these kind of GCC Git things?  If not,
please let me know.


I just took care of this; I didn't notice it until now because the 
subject line didn't seem relevant to me.



On 2023-10-26T10:21:18+0200, I wrote:

First, I've pushed into GCC upstream Git branch devel/rust/libgrust-v2
the "v2" libgrust changes as posted by Arthur, so that people can easily
test this before it getting into Git master branch.  [...]


Please now delete the GCC Git 'devel/rust/libgrust-v2' branch, which was
only used temporarily, and is now obsolete.

 $ git push upstream :devel/rust/libgrust-v2
 remote: *** Deleting branch 'devel/rust/libgrust-v2' is not allowed.
 remote: ***
 remote: *** This repository currently only allow the deletion of references
 remote: *** whose name matches the following:
 remote: ***
 remote: *** refs/users/[^/]*/heads/.*
 remote: *** refs/vendors/[^/]*/heads/.*
 remote: ***
 remote: *** Branch deletion is only allowed for user and vendor branches.  
If another branch was created by mistake, contact an administrator to delete it 
on the server with git update-ref.  If a development branch is dead, also 
contact an administrator to move it under refs/dead/heads/ rather than deleting 
it.
 remote: error: hook declined to update refs/heads/devel/rust/libgrust-v2
 To git+ssh://gcc.gnu.org/git/gcc.git
  ! [remote rejected]   devel/rust/libgrust-v2 (hook declined)
 error: failed to push some refs to 'git+ssh://gcc.gnu.org/git/gcc.git'


Grüße
  Thomas

Re: rust frontend and UTF-8/unicode processing/properties

[Jason Merrill via Gcc-rust]

On Sun, Jul 18, 2021 at 1:13 PM Ian Lance Taylor via Gcc 
wrote:

> On Sun, Jul 18, 2021 at 6:23 AM Mark Wielaard  wrote:
> >
> > For the gcc rust frontend I was thinking of importing a couple of
> > gnulib modules to help with UTF-8 processing, conversion to/from
> > unicode codepoints and determining various properties of those
> > codepoints. But it seems gcc doesn't yet have any gnulib modules
> > imported, and maybe other frontends already have helpers to this that
> > the gcc rust frontend could reuse.
> >
> > Rust only accepts valid UTF-8 encoded source files, which may or may
> > not start with UTF-8 BOM character. Whitespace is any codepoint with
> > the Pattern_White_Space property. Identifiers can start with any
> > codepoint with the XID_start property plus zero or one codepoints with
> > XID_continue property. It isn't required, but highly desirable to
> > detect confusable identifiers according to tr39/Confusable_Detection.
> >
> > Other names might be constraint to Alphabetic and/or Number categories
> > (Nd, Nl, No), textual types can only contain Unicode Scalar Values
> > (any Unicode codepoint except high-surrogate and low-surrogates),
> > strings in source code can contain unicode escapes (24 bit, up to 6
> > digits codepoints) but are internally stored as UTF-8 (and must not
> > encode any surrogates).
> >
> > Do other gcc frontends handle any of the above already in a way that
> > might be reusable for other frontends?
>
> I don't know that this is particularly helpful, but the Go frontend
> has this kind of code in gcc/go/gofrontend/lex.cc.  E.g.,
> Lex::fetch_char, Lex::advance_one_utf8_char, unicode_space,
> unicode_digits, unicode_letters, Lex::is_unicode_space, etc.  But you
> probably won't be able to use the code directly, and the code in the
> gofrontend directory is also shared with GoLLVM so it can't trivially
> be moved.
>

I believe the UTF-8 handling for the C family front ends is all in libcpp;
I don't think it's factored in a way to be useful to other front ends.

Jason
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Re: [PATCH Rust front-end v2 01/37] Use DW_ATE_UTF for the Rust 'char' type

[Jason Merrill via Gcc-rust]

On 8/24/22 04:59, herron.phi...@googlemail.com wrote:

From: Tom Tromey 

The Rust 'char' type should use the DWARF DW_ATE_UTF encoding.


The DWARF changes are OK.


---
  gcc/dwarf2out.cc | 23 ++-
  1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/gcc/dwarf2out.cc b/gcc/dwarf2out.cc
index e3920c898f5..a8bccbabca4 100644
--- a/gcc/dwarf2out.cc
+++ b/gcc/dwarf2out.cc
@@ -5600,6 +5600,16 @@ is_fortran (const_tree decl)
return is_fortran ();
  }
  
+/* Return TRUE if the language is Rust.  */

+
+static inline bool
+is_rust ()
+{
+  unsigned int lang = get_AT_unsigned (comp_unit_die (), DW_AT_language);
+
+  return lang == DW_LANG_Rust || lang == DW_LANG_Rust_old;
+}
+
  /* Return TRUE if the language is Ada.  */
  
  static inline bool

@@ -13231,7 +13241,11 @@ base_type_die (tree type, bool reverse)
}
if (TYPE_STRING_FLAG (type))
{
- if (TYPE_UNSIGNED (type))
+ if ((dwarf_version >= 4 || !dwarf_strict)
+ && is_rust ()
+ && int_size_in_bytes (type) == 4)
+   encoding = DW_ATE_UTF;
+ else if (TYPE_UNSIGNED (type))
encoding = DW_ATE_unsigned_char;
  else
encoding = DW_ATE_signed_char;
@@ -25201,6 +25215,13 @@ gen_compile_unit_die (const char *filename)
  }
else if (strcmp (language_string, "GNU F77") == 0)
  language = DW_LANG_Fortran77;
+  else if (strcmp (language_string, "GNU Rust") == 0)
+{
+  if (dwarf_version >= 5 || !dwarf_strict)
+   language = DW_LANG_Rust;
+  else
+   language = DW_LANG_Rust_old;
+}
else if (dwarf_version >= 3 || !dwarf_strict)
  {
if (strcmp (language_string, "GNU Ada") == 0)


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