Rust: In 'type_for_mode' langhook also consider all 'int_n' modes/types (was: Modula-2 / Rust: Many targets failing)

[Thomas Schwinge <thomas@codesourcery.com>]

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Hi!

Richard, you may remember your words from <https://gcc.gnu.org/PR46805>
"ICE: SIGSEGV in optab_for_tree_code (optabs.c:407) with -O -fno-tree-scev-cprop -ftree-vectorize":

> Ideally we'd never use lang_hooks.types.type_for_mode (or _for_size) in the
> middle-end but had a pure middle-end based implementation.

Is there a canonical PR or other discussion thread for that?

Here's another instance of this issue:

On 2022-12-19T22:23:45+0100, Jan-Benedict Glaw <jbglaw@lug-owl.de> wrote:
> With the recent merges for Modula-2 and Rust, I see a good number of
> targets failing with --enable-languages=all, mostly due to issues with
> the Modula-2 driver.

Thanks for reporting.

>  Modula-2 related issues
> [snipped]

>  Rust related issues
> =====================
>
>  --target=msp430-elfbare
> ~~~~~~~~~~~~~~~~~~~~~~~~~
>       /var/lib/laminar/run/gcc-msp430-elfbare/24/toolchain-build/./gcc/xgcc -B/var/lib/laminar/run/gcc-msp430-elfbare/24/toolchain-build/./gcc/  -xrust -frust-incomplete-and-experimental-compiler-do-not-use -nostdinc /dev/null -S -o /dev/null -fself-test=../../gcc/gcc/testsuite/selftests
>       <built-in>: internal compiler error: Segmentation fault
>       0xf2efbf crash_signal
>             ../../gcc/gcc/toplev.cc:314
>       0x120c8c7 build_function_type(tree_node*, tree_node*, bool)
>             ../../gcc/gcc/tree.cc:7360
>       0x120cc20 build_function_type_list(tree_node*, ...)
>             ../../gcc/gcc/tree.cc:7442
>       0x120d16b build_common_builtin_nodes()
>             ../../gcc/gcc/tree.cc:9883
>       0x8449b4 grs_langhook_init
>             ../../gcc/gcc/rust/rust-lang.cc:132
>       0x8427b2 lang_dependent_init
>             ../../gcc/gcc/toplev.cc:1815
>       0x8427b2 do_compile
>             ../../gcc/gcc/toplev.cc:2110
>       Please submit a full bug report, with preprocessed source (by using -freport-bug).
>       Please include the complete backtrace with any bug report.
>       See <https://gcc.gnu.org/bugs/> for instructions.
>       make[1]: *** [../../gcc/gcc/rust/Make-lang.in:275: s-selftest-rust] Error 1

See also <https://github.com/Rust-GCC/gccrs/issues/1713>
"Test failure on msp430-elfbare target".

I confirm with both upstream GCC master branch and GCC/Rust master
branch:

    $ ../source-gcc/configure --target=msp430-elfbare --enable-languages=rust [...]
    $ make all-gcc [...]
    [...]
    [...]/build-gcc/./gcc/xgcc -B[...]/build-gcc/./gcc/  -xc -nostdinc /dev/null -S -o /dev/null -fself-test=../../source-gcc/gcc/testsuite/selftests
    -fself-test: 57323 pass(es) in 0.420000 seconds
    echo timestamp > s-selftest-c
    [...]/build-gcc/./gcc/xgcc -B[...]/build-gcc/./gcc/  -xrust -frust-incomplete-and-experimental-compiler-do-not-use -nostdinc /dev/null -S -o /dev/null -fself-test=../../source-gcc/gcc/testsuite/selftests
    <built-in>: internal compiler error: Segmentation fault
    0xf51b9f crash_signal
            ../../source-gcc/gcc/toplev.cc:314
    0x12e6a3a build_function_type(tree_node*, tree_node*, bool)
            ../../source-gcc/gcc/tree.cc:7447
    0x12e6ee0 build_function_type_list(tree_node*, ...)
            ../../source-gcc/gcc/tree.cc:7529
    0x12e748e build_common_builtin_nodes()
            ../../source-gcc/gcc/tree.cc:9977
    0x7661c4 grs_langhook_init
            ../../source-gcc/gcc/rust/rust-lang.cc:128
    0x762ac9 lang_dependent_init
            ../../source-gcc/gcc/toplev.cc:1815
    0x762ac9 do_compile
            ../../source-gcc/gcc/toplev.cc:2110
    Please submit a full bug report, with preprocessed source (by using -freport-bug).
    Please include the complete backtrace with any bug report.
    See <https://gcc.gnu.org/bugs/> for instructions.
    make[1]: *** [s-selftest-rust] Error 1
    [...]

OK to push the attached
"Rust: In 'type_for_mode' langhook also consider all 'int_n' modes/types"?


Grüße
 Thomas


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From cae898bef63db18cc40b94ee4d48f85aec258c02 Mon Sep 17 00:00:00 2001
From: Thomas Schwinge <thomas@codesourcery.com>
Date: Wed, 22 Feb 2023 11:42:43 +0100
Subject: [PATCH] Rust: In 'type_for_mode' langhook also consider all 'int_n'
 modes/types

As reported in "Rust related issues" at the end of
<https://inbox.sourceware.org/gcc-patches/20221219212344.ewtuzd2jtztm77x2@lug-owl.de>
"Modula-2 / Rust: Many targets failing",
<https://github.com/Rust-GCC/gccrs/issues/1713>
"Test failure on msp430-elfbare target", for '--target=msp430-elfbar' we ICE:

    <built-in>: internal compiler error: Segmentation fault
    0xf2efbf crash_signal
          ../../gcc/gcc/toplev.cc:314
    0x120c8c7 build_function_type(tree_node*, tree_node*, bool)
          ../../gcc/gcc/tree.cc:7360
    0x120cc20 build_function_type_list(tree_node*, ...)
          ../../gcc/gcc/tree.cc:7442
    0x120d16b build_common_builtin_nodes()
          ../../gcc/gcc/tree.cc:9883
    0x8449b4 grs_langhook_init
          ../../gcc/gcc/rust/rust-lang.cc:132
    [...]

This is due to 'tmp == NULL' for 'gcc/tree.cc:build_common_builtin_nodes':

    tmp = lang_hooks.types.type_for_mode (targetm.eh_return_filter_mode (), 0);

..., were 'targetm.eh_return_filter_mode' (that is,
'gcc/targhooks.cc:default_eh_return_filter_mode',
via calling 'targetm.unwind_word_mode':
'gcc/config/msp430/msp430.cc:msp430_unwind_word_mode') returns 'PSImode',
and 'lang_hooks.types.type_for_mode' (that is,
'gcc/rust/rust-lang.cc:grs_langhook_type_for_mode') returns 'NULL' for
'PSImode'.

As, for example, discussed in <https://gcc.gnu.org/PR46805>
"ICE: SIGSEGV in optab_for_tree_code (optabs.c:407) with -O -fno-tree-scev-cprop -ftree-vectorize",
we have to support "random" modes/types in the 'type_for_mode' langhook.

	gcc/rust/
	* rust-lang.cc (grs_langhook_type_for_mode): Also consider all
	'int_n' modes/types.
---
 gcc/rust/rust-lang.cc | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/gcc/rust/rust-lang.cc b/gcc/rust/rust-lang.cc
index 75f6b4458d7..b4b86236ffc 100644
--- a/gcc/rust/rust-lang.cc
+++ b/gcc/rust/rust-lang.cc
@@ -235,6 +235,21 @@ grs_langhook_type_for_mode (machine_mode mode, int unsignedp)
       if (mode == TYPE_MODE (complex_integer_type_node) && !unsignedp)
 	return complex_integer_type_node;
     }
+
+  /* See (a) <https://github.com/Rust-GCC/gccrs/issues/1713>
+     "Test failure on msp430-elfbare target", and
+     (b) <https://gcc.gnu.org/PR46805>
+     "ICE: SIGSEGV in optab_for_tree_code (optabs.c:407) with -O -fno-tree-scev-cprop -ftree-vectorize"
+     -- we have to support "random" modes/types here.
+     TODO Clean all this up (either locally, or preferably per PR46805:
+     "Ideally we'd never use lang_hooks.types.type_for_mode (or _for_size) in the
+     middle-end but had a pure middle-end based implementation".  */
+  for (size_t i = 0; i < NUM_INT_N_ENTS; i ++)
+    if (int_n_enabled_p[i]
+	&& mode == int_n_data[i].m)
+      return (unsignedp ? int_n_trees[i].unsigned_type
+	      : int_n_trees[i].signed_type);
+
   /* gcc_unreachable */
   return NULL;
 }
-- 
2.25.1