[Bug c++/30988] New: Incorrect "no return statement" warning with __attribute__ ((noreturn)) and __FUNCTION__

[Bug c++/30988] New: Incorrect "no return statement" warning with __attribute__ ((noreturn)) and __FUNCTION__

[irving at cs dot stanford dot edu]

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The following code incorrectly warns that the function g is missing a return
statement.  The warning goes away if __FUNCTION__ is replaced by
(const char*)__FUNCTION__.

================ BEGIN CODE ==================
void f(const char*) __attribute__ ((noreturn));

template<class T>
class A
{
    int g()
    {
        f(__FUNCTION__);
        //f((const char*)__FUNCTION__);
    }
};

template class A<int>;
============================ END code

wedge:scratch% g++ -O3 -Wall -c -v noreturn.cpp
Using built-in specs.
Target: x86_64-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man
--infodir=/usr/share/info --enable-shared --enable-threads=posix
--enable-checking=release --with-system-zlib --enable-__cxa_atexit
--disable-libunwind-exceptions --enable-libgcj-multifile
--enable-languages=c,c++,objc,obj-c++,java,fortran,ada --enable-java-awt=gtk
--disable-dssi --with-java-home=/usr/lib/jvm/java-1.4.2-gcj-1.4.2.0/jre
--with-cpu=generic --host=x86_64-redhat-linux
Thread model: posix
gcc version 4.1.1 20060525 (Red Hat 4.1.1-1)
 /usr/libexec/gcc/x86_64-redhat-linux/4.1.1/cc1plus -quiet -v -D_GNU_SOURCE
noreturn.cpp -quiet -dumpbase noreturn.cpp -mtune=generic -auxbase noreturn -O3
-Wall -version -o /tmp/ccVj3EZ3.s
ignoring nonexistent directory
"/usr/lib/gcc/x86_64-redhat-linux/4.1.1/../../../../x86_64-redhat-linux/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/lib/gcc/x86_64-redhat-linux/4.1.1/../../../../include/c++/4.1.1

/usr/lib/gcc/x86_64-redhat-linux/4.1.1/../../../../include/c++/4.1.1/x86_64-redhat-linux
 /usr/lib/gcc/x86_64-redhat-linux/4.1.1/../../../../include/c++/4.1.1/backward
 /usr/local/include
 /usr/lib/gcc/x86_64-redhat-linux/4.1.1/include
 /usr/include
End of search list.
GNU C++ version 4.1.1 20060525 (Red Hat 4.1.1-1) (x86_64-redhat-linux)
        compiled by GNU C version 4.1.1 20060525 (Red Hat 4.1.1-1).
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 56236c31509b2b0d4a3c4ac0327da7d9
noreturn.cpp: In member function ‘int A<T>::g()’:
noreturn.cpp:10: warning: no return statement in function returning non-void
 as -V -Qy -o noreturn.o /tmp/ccVj3EZ3.s
GNU assembler version 2.16.91.0.6 (x86_64-redhat-linux) using BFD version
2.16.91.0.6 20060212


-- 
           Summary: Incorrect "no return statement" warning with
                    __attribute__ ((noreturn)) and __FUNCTION__
           Product: gcc
           Version: 4.1.1
            Status: UNCONFIRMED
          Severity: minor
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: irving at cs dot stanford dot edu
 GCC build triplet: x86_64-redhat-linux
  GCC host triplet: x86_64-redhat-linux
GCC target triplet: x86_64-redhat-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30988

[Bug c++/30988] Incorrect "no return statement" warning with __attribute__ ((noreturn)) and __FUNCTION__

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2007-02-28 00:26 -------
*** Bug 30993 has been marked as a duplicate of this bug. ***


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30988

[Bug c++/30988] [4.1/4.2/4.3 Regression] Incorrect "no return statement" warning with __attribute__ ((noreturn)) and __FUNCTION__

[pinskia at gcc dot gnu dot org]

------- Comment #2 from pinskia at gcc dot gnu dot org  2007-03-03 21:50 -------
Confirmed, a regression from 3.3.3.  I made sure in 3.3.3, we would warn about
the function if we removed the attribute noreturn so I know the warning works
for that case.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
      Known to fail|                            |3.4.0 4.0.0 4.1.0 4.2.0
      Known to work|                            |3.3.3
   Last reconfirmed|0000-00-00 00:00:00         |2007-03-03 21:50:09
               date|                            |
            Summary|Incorrect "no return        |[4.1/4.2/4.3 Regression]
                   |statement" warning with     |Incorrect "no return
                   |__attribute__ ((noreturn))  |statement" warning with
                   |and __FUNCTION__            |__attribute__ ((noreturn))
                   |                            |and __FUNCTION__
   Target Milestone|---                         |4.1.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30988

[Bug c++/30988] [4.1/4.2/4.3 Regression] Incorrect "no return statement" warning with __attribute__ ((noreturn)) and __FUNCTION__

[mmitchel at gcc dot gnu dot org]

-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30988

[Bug c++/30988] [4.1/4.2/4.3 Regression] Incorrect "no return statement" warning with __attribute__ ((noreturn)) and __FUNCTION__

[spark at gcc dot gnu dot org]

------- Comment #3 from spark at gcc dot gnu dot org  2007-03-13 22:57 -------
This is somewhat complicated. 
The extra type cast causes
different code paths to be taken.
In particular, in finish_call_expr() in cp/semantics.c:

  if (processing_template_decl)
    {
      if (type_dependent_expression_p (fn)
          || any_type_dependent_arguments_p (args))
        {
          result = build_nt_call_list (fn, args);
          KOENIG_LOOKUP_P (result) = koenig_p;
          return result;
        }
      if (!BASELINK_P (fn)
          && TREE_CODE (fn) != PSEUDO_DTOR_EXPR
          && TREE_TYPE (fn) != unknown_type_node)
        fn = build_non_dependent_expr (fn);
      args = build_non_dependent_args (orig_args);



With the type cast, 
build_over_call() is called eventually
which checks TREE_THIS_VOLATILE() for the callee function decl
and mark the current function (i.e. caller A::g) as returns_abnormally.
The lack of the type cast triggers
any_type_dependent_arguments_p(args) above,
leading to build_nt_call_list() which doesn't do this marking
of the returns_abnormally.

Now, not being familiar with the c++ frontend,
I'm not sure where exactly we should do the checking
of TREE_THIS_VOLATILE() for the callee decl.

The following patch seems to fix the problem 
(though I can't even tell whether this is the right approach):

diff -r 15a559a8fcf0 gcc/cp/semantics.c
--- a/gcc/cp/semantics.c        Mon Mar 12 15:38:22 2007 -0700
+++ b/gcc/cp/semantics.c        Tue Mar 13 15:48:45 2007 -0700
@@ -1816,6 +1816,10 @@ finish_call_expr (tree fn, tree args, bo
          || any_type_dependent_arguments_p (args))
        {
          result = build_nt_call_list (fn, args);
+
+         if (fn && TREE_THIS_VOLATILE (fn) && cfun)
+           current_function_returns_abnormally = 1;
+
          KOENIG_LOOKUP_P (result) = koenig_p;
          return result;
        }


-- 

spark at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |spark at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30988

[Bug c++/30988] [4.1/4.2/4.3 Regression] Incorrect "no return statement" warning with __attribute__ ((noreturn)) and __FUNCTION__

[jakub at gcc dot gnu dot org]

------- Comment #4 from jakub at gcc dot gnu dot org  2007-11-17 12:33 -------
IMNSHO this is not a regression.
void f (const char *)
#ifdef NORET
__attribute__ ((noreturn))
#endif
;

template <class T> struct A
{
  int g ()
  {
#ifdef TEST1
    f (__FUNCTION__);
#elif defined TEST2
    f ((const char*) __FUNCTION__);
#else
    f ((const char *) 0);
#endif
  }
};

for k in gcc-2.96-rh gcc-3.2 gcc-3.3 gcc-3.4 gcc-4.1 gcc-4.2 gcc-4.3; do for i
in " -DNORET" ""; do \
  for j in -DTEST1 -DTEST3 -DTEST3; do \
    /usr/src/$k/obj/gcc/cc1plus $i $j pr30988.C -O3 -Wall -quiet 2>&1 \
      | sed -n "/warning:/s/^/$k$i $j /p"; done; done; done
gcc-3.2 -DNORET -DTEST1 pr30988.C:18: warning: no return statement in function
returning non-void
gcc-3.2 -DNORET -DTEST3 pr30988.C:18: warning: no return statement in function
returning non-void
gcc-3.2 -DNORET -DTEST3 pr30988.C:18: warning: no return statement in function
returning non-void
gcc-3.2 -DTEST1 pr30988.C:18: warning: no return statement in function
returning non-void
gcc-3.2 -DTEST3 pr30988.C:18: warning: no return statement in function
returning non-void
gcc-3.2 -DTEST3 pr30988.C:18: warning: no return statement in function
returning non-void
gcc-3.4 -DNORET -DTEST1 pr30988.C:18: warning: no return statement in function
returning non-void
gcc-3.4 -DTEST1 pr30988.C:18: warning: no return statement in function
returning non-void
gcc-3.4 -DTEST3 pr30988.C:18: warning: no return statement in function
returning non-void
gcc-3.4 -DTEST3 pr30988.C:18: warning: no return statement in function
returning non-void
gcc-4.1 -DNORET -DTEST1 pr30988.C:18: warning: no return statement in function
returning non-void
gcc-4.1 -DTEST1 pr30988.C:18: warning: no return statement in function
returning non-void
gcc-4.1 -DTEST3 pr30988.C:18: warning: no return statement in function
returning non-void
gcc-4.1 -DTEST3 pr30988.C:18: warning: no return statement in function
returning non-void
gcc-4.2 -DNORET -DTEST1 pr30988.C:18: warning: no return statement in function
returning non-void
gcc-4.2 -DTEST1 pr30988.C:18: warning: no return statement in function
returning non-void
gcc-4.2 -DTEST3 pr30988.C:18: warning: no return statement in function
returning non-void
gcc-4.2 -DTEST3 pr30988.C:18: warning: no return statement in function
returning non-void
gcc-4.3 -DNORET -DTEST1 pr30988.C:18: warning: no return statement in function
returning non-void
gcc-4.3 -DTEST1 pr30988.C:18: warning: no return statement in function
returning non-void
gcc-4.3 -DTEST3 pr30988.C:18: warning: no return statement in function
returning non-void
gcc-4.3 -DTEST3 pr30988.C:18: warning: no return statement in function
returning non-void

So, gcc-2.96-RH and 3.3 wouldn't warn ever in templates, even for cases where
it should warn, e.g. when the argument is not type dependent and neither the
called function has noreturn attribute.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30988

[Bug c++/30988] [4.1/4.2/4.3 Regression] Incorrect "no return statement" warning with __attribute__ ((noreturn)) and __FUNCTION__

[jakub at gcc dot gnu dot org]

------- Comment #5 from jakub at gcc dot gnu dot org  2007-11-17 12:35 -------
Oops, sorry for the typo (twice -DTEST3, never -DTEST2).  But with -DTEST2 the
output is always identical to -DTEST3 with all compilers.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30988

[Bug c++/30988] [4.1/4.2/4.3 Regression] Incorrect "no return statement" warning with __attribute__ ((noreturn)) and __FUNCTION__

[jakub at gcc dot gnu dot org]

------- Comment #6 from jakub at gcc dot gnu dot org  2007-11-18 22:21 -------
Subject: Bug 30988

Author: jakub
Date: Sun Nov 18 22:20:54 2007
New Revision: 130280

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=130280
Log:
        PR c++/30988
        semantics.c (finish_call_expr): Set current_function_returns_abnormally
        if fn is noreturn FUNCTION_DECL or OVERLOAD with all noreturn
        functions.

        * g++.dg/warn/noreturn-4.C: New test.
        * g++.dg/warn/noreturn-5.C: New test.
        * g++.dg/warn/noreturn-6.C: New test.
        * g++.dg/warn/noreturn-7.C: New test.

Added:
    trunk/gcc/testsuite/g++.dg/warn/noreturn-4.C
    trunk/gcc/testsuite/g++.dg/warn/noreturn-5.C
    trunk/gcc/testsuite/g++.dg/warn/noreturn-6.C
    trunk/gcc/testsuite/g++.dg/warn/noreturn-7.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/semantics.c
    trunk/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30988

[Bug c++/30988] [4.1/4.2 Regression] Incorrect "no return statement" warning with __attribute__ ((noreturn)) and __FUNCTION__

[jakub at gcc dot gnu dot org]

------- Comment #7 from jakub at gcc dot gnu dot org  2007-11-18 22:21 -------
Fixed on the trunk.


-- 

jakub at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |jakub at gcc dot gnu dot org
                   |dot org                     |
             Status|NEW                         |ASSIGNED
      Known to work|3.3.3                       |3.3.3 4.3.0
   Last reconfirmed|2007-03-03 21:50:09         |2007-11-18 22:21:37
               date|                            |
            Summary|[4.1/4.2/4.3 Regression]    |[4.1/4.2 Regression]
                   |Incorrect "no return        |Incorrect "no return
                   |statement" warning with     |statement" warning with
                   |__attribute__ ((noreturn))  |__attribute__ ((noreturn))
                   |and __FUNCTION__            |and __FUNCTION__


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30988

[Bug c++/30988] [4.2 Regression] Incorrect "no return statement" warning with __attribute__ ((noreturn)) and __FUNCTION__

[jsm28 at gcc dot gnu dot org]

------- Comment #8 from jsm28 at gcc dot gnu dot org  2008-07-04 21:59 -------
Closing 4.1 branch.


-- 

jsm28 at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[4.1/4.2 Regression]        |[4.2 Regression] Incorrect
                   |Incorrect "no return        |"no return statement"
                   |statement" warning with     |warning with __attribute__
                   |__attribute__ ((noreturn))  |((noreturn)) and
                   |and __FUNCTION__            |__FUNCTION__
   Target Milestone|4.1.3                       |4.2.5


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30988

[Bug c++/30988] [4.2 Regression] Incorrect "no return statement" warning with __attribute__ ((noreturn)) and __FUNCTION__

[jsm28 at gcc dot gnu dot org]

------- Comment #9 from jsm28 at gcc dot gnu dot org  2009-03-30 21:40 -------
Closing 4.2 branch, fixed in 4.3.


-- 

jsm28 at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
      Known to fail|3.4.0 4.0.0 4.1.0 4.2.0     |3.4.0 4.0.0 4.1.0 4.2.0
                   |                            |4.2.5
         Resolution|                            |FIXED
   Target Milestone|4.2.5                       |4.3.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30988

[Bug c++/30988] [4.2 Regression] Incorrect "no return statement" warning with __attribute__ ((noreturn)) and __FUNCTION__

[irving at naml dot us]

------- Comment #10 from irving at naml dot us  2009-03-30 21:43 -------
(In reply to comment #9)
> Closing 4.2 branch, fixed in 4.3.

Thanks!


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30988