[Bug c++/112588] New: ICE in make_decl_rtl when returning str literal when string header imported in module

[Bug c++/112588] New: ICE in make_decl_rtl when returning str literal when string header imported in module

[nickbegg at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112588

            Bug ID: 112588
           Summary: ICE in make_decl_rtl when returning str literal when
                    string header imported in module
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: nickbegg at gmail dot com
  Target Milestone: ---

Created attachment 56622
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56622&action=edit
-freport-bug output

/home/nick/gcc-trunk-debug-inst/include/c++/14.0.0/bits/allocator.h:191:39:
internal compiler error: in make_decl_rtl, at varasm.cc:1442
  191 |             if (__builtin_mul_overflow(__n, sizeof(_Tp), &__n))
      |                 ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

Using when importing a module into a non-module TU, #including string in both
causes an ICE when returning a string literal in a function with std::string
return type -

////////////////////////
// modA.mpp (compiled as module):

module;

#include <string>

export module modA;

///////////////////////
// main.cpp (compiled as regular TU): 

#include <string>

import modA;

std::string test_func() {
    return "foo";
}

int main() {
    return 0;
}
///////////////////////

The ICE happens when compiling main.cpp.

Removing the import from main.cpp, or returning std::string() from test_func()
stops the ICE. 

GCC trunk (14) version, git rev ba3f5b8465ef7b278ea33ff94cd85b9638058635

[Bug c++/112588] ICE in make_decl_rtl when returning str literal when string header imported in module

[nathanieloshead at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112588

Nathaniel Shead <nathanieloshead at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |nathanieloshead at gmail dot com

--- Comment #1 from Nathaniel Shead <nathanieloshead at gmail dot com> ---
Minimised (the actual offender here is the with std::allocator<char>):


  // test.h
  void f(int*);

  template <typename T>
  struct S {
    void g(int n) { f(&n); }
  };

  template struct S<void>;


  // a.cpp
  module;
  #include "test.h"
  export module test;


  // b.cpp
  #include "test.h"
  import test;


So far it seems the issue is that the PARM_DECL in the expression tree of the
body of the instantiation for `S<void>::g` is a different node from the actual
PARM_DECL in g's DECL_ARGUMENTS; the latter gets RTL but the former does not.
The issue is in the deduplication logic for instantiations somewhere.

The following patch fixes this issue but causes other issues in the testsuite,
and I don't think this is the correct approach anyway:


diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index 4f5b6e2747a..f2d191fc408 100644
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -8302,9 +8302,7 @@ trees_in::decl_value ()
       if (TREE_CODE (inner) == FUNCTION_DECL)
        {
          tree e_inner = STRIP_TEMPLATE (existing);
-         for (auto parm = DECL_ARGUMENTS (inner);
-              parm; parm = DECL_CHAIN (parm))
-           DECL_CONTEXT (parm) = e_inner;
+         DECL_ARGUMENTS (inner) = DECL_ARGUMENTS (e_inner);
        }

       /* And our result is the existing node.  */


(I was originally working on this after attempting to reduce PR99999.)

[Bug c++/112588] ICE in make_decl_rtl when returning str literal when string header imported in module

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112588

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ma.anshukov at gmail dot com

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 112805 has been marked as a duplicate of this bug. ***

[Bug c++/112588] ICE in make_decl_rtl when returning str literal when string header imported in module

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112588

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=99244
                 CC|                            |ppalka at gcc dot gnu.org

--- Comment #3 from Patrick Palka <ppalka at gcc dot gnu.org> ---
The proposed patch seems to fix PR99244 as well

[Bug c++/112588] [modules] ICE in make_decl_rtl when returning str literal when string header imported in module

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112588

--- Comment #4 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Nathaniel Shead <nshead@gcc.gnu.org>:

https://gcc.gnu.org/g:3471a61ed0ddef70de8f1bbba85cd1e945fc86fd

commit r14-8196-g3471a61ed0ddef70de8f1bbba85cd1e945fc86fd
Author: Nathaniel Shead <nathanieloshead@gmail.com>
Date:   Sat Dec 16 21:34:45 2023 +1100

    c++: Prevent overwriting arguments when merging duplicates [PR112588]

    When merging duplicate instantiations of function templates, currently
    read_function_def overwrites the arguments with that of the existing
    duplicate. This is problematic, however, since this means that the
    PARM_DECLs in the body of the function definition no longer match with
    the PARM_DECLs in the argument list, which causes issues when it comes
    to generating RTL.

    There doesn't seem to be any reason to do this replacement, so this
    patch removes that logic.

            PR c++/112588

    gcc/cp/ChangeLog:

            * module.cc (trees_in::read_function_def): Don't overwrite
            arguments.

    gcc/testsuite/ChangeLog:

            * g++.dg/modules/merge-16.h: New test.
            * g++.dg/modules/merge-16_a.C: New test.
            * g++.dg/modules/merge-16_b.C: New test.

    Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>

[Bug c++/112588] [modules] ICE in make_decl_rtl when returning str literal when string header imported in module

[hp at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112588

Hans-Peter Nilsson <hp at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hp at gcc dot gnu.org

--- Comment #5 from Hans-Peter Nilsson <hp at gcc dot gnu.org> ---
Looks like that commit also fixed the remaining g++.dg/modules/hello-1
execution failure for PR113038!

[Bug c++/112588] [modules] ICE in make_decl_rtl when returning str literal when string header imported in module

[nshead at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112588

Nathaniel Shead <nshead at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |14.0
           Keywords|                            |ice-on-valid-code
             Status|UNCONFIRMED                 |RESOLVED
           Assignee|unassigned at gcc dot gnu.org      |nshead at gcc dot gnu.org
         Resolution|---                         |FIXED

--- Comment #6 from Nathaniel Shead <nshead at gcc dot gnu.org> ---
Fixed for GCC 14.

[Bug c++/112588] [modules] ICE in make_decl_rtl when returning str literal when string header imported in module

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112588

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |f.b.brokken at rug dot nl

--- Comment #7 from Patrick Palka <ppalka at gcc dot gnu.org> ---
*** Bug 104202 has been marked as a duplicate of this bug. ***