c++/3395: Attribute causes type lookup to fail. Regression.

c++/3395: Attribute causes type lookup to fail. Regression.

[khan]

>Number:         3395
>Category:       c++
>Synopsis:       Attribute causes type lookup to fail. Regression.
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          rejects-legal
>Submitter-Id:   net
>Arrival-Date:   Mon Jun 25 00:36:01 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator:     Mumit Khan
>Release:        3.0
>Organization:
>Environment:
Cygwin, Mingw and other x86-win32 targets. Host independent.
>Description:
See attached file.
>How-To-Repeat:
Just compiling the provided testcase will trigger the problem.
>Fix:
None known.
>Release-Note:
>Audit-Trail:
>Unformatted:
----gnatsweb-attachment----
Content-Type: text/plain; name="gcc-bug2.txt"
Content-Disposition: inline; filename="gcc-bug2.txt"

The following code causes the C++ front-end to report errors where
there are none. Regression from 2.95.x, and unfortunately causes
most of C++ code that uses/creates windows DLL to fail.

  struct
  __attribute__((dllexport))
  c {
    void f () const;
  };
   
  inline void
  c::f () const
  { }

Here's what cc1plus says:

  $ ./cc1plus -quiet -version dll-bug2.ii
  GNU CPP version 3.0 (cpplib) (80386, BSD syntax)
  GNU C++ version 3.0 (i686-pc-cygwin)
	  compiled by GNU C version 3.0.
  dll-bug2.ii:9: prototype for `void c::f() const' does not match any in
  class
     `c'
  dll-bug2.ii:4: candidate is: void c::f() const

The problem happens when parsing the definition of c::f.

PARSER -> ... -> check_classfn -> compparms -> same_type_p returns 0.

See notes marked with >>>> and ^^^^^ below. Putting the attribute *before*
the class/struct causes no errors, but that's not consistent with existing
code.

(gdb) b check_classfn
(gdb) run dll-bug2.ii
Starting program: /homes/khan/src/win32/cygwin/BUILD/orig-gcc3/gcc/cc1plus
dll-bug2.ii
 
Breakpoint 4, check_classfn (ctype=0x401715b0, function=0x40175888)
    at /home/khan/src/gnu/gcc-3.0/gcc/cp/decl2.c:1364
1364      tree fn_name = DECL_NAME (function);
(gdb) b compparms
Breakpoint 10 at 0x80bdbd6: file
/home/khan/src/gnu/gcc-3.0/gcc/cp/typeck.c, line 1445.
(gdb) c
Continuing.
 
Breakpoint 10, compparms (parms1=0x40174370, parms2=0x40174078)
    at /home/khan/src/gnu/gcc-3.0/gcc/cp/typeck.c:1445
1445      register tree t1 = parms1, t2 = parms2;
(gdb) bt
#0  compparms (parms1=0x40174370, parms2=0x40174078)
    at /home/khan/src/gnu/gcc-3.0/gcc/cp/typeck.c:1452

<<<< NOTE: parms1 and parms2 are different! Also, see note below,
<<<< where TREE_VALUE (parms1) and TREE_VALUE (parms2) are different
<<<< so that same_types_p returns 0.

#1  0x809849a in check_classfn (ctype=0x401715b0, function=0x40175888)
    at /home/khan/src/gnu/gcc-3.0/gcc/cp/decl2.c:1432
#2  0x80662f8 in grokfndecl (ctype=0x401715b0, type=0x401717b8,
    declarator=0x401640c0, orig_declarator=0x401640c0, virtualp=0,
    flags=NO_SPECIAL, quals=0x40174320, raises=0x0, check=1, friendp=0,
    publicp=1, inlinep=1, funcdef_flag=1, template_count=0,
in_namespace=0x0)
    at /home/khan/src/gnu/gcc-3.0/gcc/cp/decl.c:8987
#3  0x806ba2d in grokdeclarator (declarator=0x401640c0,
declspecs=0x401742e4,
    decl_context=NORMAL, initialized=1, attrlist=0x0)
    at /home/khan/src/gnu/gcc-3.0/gcc/cp/decl.c:11605
#4  0x806fc8a in start_function (declspecs=0x401742e4,
declarator=0x40167880,
    attrs=0x0, flags=0) at /home/khan/src/gnu/gcc-3.0/gcc/cp/decl.c:13334
#5  0x80df16c in begin_function_definition (decl_specs=0x401742e4,
    declarator=0x40167880)
    at /home/khan/src/gnu/gcc-3.0/gcc/cp/semantics.c:1614
#6  0x80aabf1 in yyparse_1 () at /usr/lib/bison.simple:804
#7  0x80fd26d in yyparse () at /home/khan/src/gnu/gcc-3.0/gcc/c-lex.c:158
#8  0x81026e3 in compile_file (name=0x844f207 "dll-bug2.ii")
    at /home/khan/src/gnu/gcc-3.0/gcc/toplev.c:2369
#9  0x81069c6 in main (argc=2, argv=0xbffff704)
    at /home/khan/src/gnu/gcc-3.0/gcc/toplev.c:4990
(gdb) p parms1
(gdb) pt
 <tree_list 0x40174370 side-effects
    value <pointer_type 0x40175958
                        ^^^^^^^^^^ (1)
        type <record_type 0x40171d00 c readonly type_1 type_5 QI
            size <integer_cst 0x4015e400 constant 8>
            unit size <integer_cst 0x4015eac0 constant 1>
            user align 8 symtab 0 alias set -1
            attributes <tree_list 0x401740b4
                purpose <identifier_node 0x40170380 dllexport
                    bindings <binding 0x40163f14 scope 0x40162000>>>
fields <type_decl 0x401716e8 c>
            X() X(constX&) this=(X&) n_parents 0 use_template=0
interface-unknown vtable-needs-writing
            member-functions <tree_vec 0x40170f00
                elt 0 <overload 0x40173450>
                elt 2 <function_decl 0x40175270 operator=>
                elt 3 <overload 0x40173490>
                elt 4 <overload 0x40173470>
                elt 5 <function_decl 0x40171820 f>>
            pointer_to_this <pointer_type 0x40175958> reference_to_this
<reference_type 0x40171d68>>
        unsigned SI
        size <integer_cst 0x4015eb20 constant 32>
        unit size <integer_cst 0x4015eb40 constant 4>
        align 32 symtab 0 alias set -1>
    chain <tree_list 0x40163668 tree_2
        value <void_type 0x401656e8 void type_6 VOID
            align 8 symtab 0 alias set -1
            pointer_to_this <pointer_type 0x40165750>>>>

(gdb) p parms2
$9 = 0x40174078
(gdb) pt
 <tree_list 0x40174078 side-effects
    value <pointer_type 0x40171958
                        ^^^^^^^^^^ (2) See (1) above.
        type <record_type 0x40171888 c
            type <tree_list 0x40163f28
                purpose <identifier_node 0x40170380 dllexport
                    bindings <binding 0x40163f14 scope 0x40162000>>>
            readonly type_1 type_5 QI
            size <integer_cst 0x4015e400 constant 8>
            unit size <integer_cst 0x4015eac0 constant 1>
            user align 8 symtab 0 alias set -1 fields <type_decl
0x401716e8 c>
            X() X(constX&) this=(X&) n_parents 0 use_template=0
interface-unknown vtable-needs-writing
            member-functions <tree_vec 0x40170f00
                elt 0 <overload 0x40173450>
                elt 2 <function_decl 0x40175270 operator=>
                elt 3 <overload 0x40173490>
                elt 4 <overload 0x40173470>
                elt 5 <function_decl 0x40171820 f>>
            pointer_to_this <pointer_type 0x40171958>>
        unsigned SI
        size <integer_cst 0x4015eb20 constant 32>
        unit size <integer_cst 0x4015eb40 constant 4>
        align 32 symtab 0 alias set -1>
    chain <tree_list 0x40163668 tree_2
        value <void_type 0x401656e8 void type_6 VOID
            align 8 symtab 0 alias set -1
            pointer_to_this <pointer_type 0x40165750>>>>
(gdb) 

Re: c++/3395: Attribute causes type lookup to fail. Regression.

[jason]

Synopsis: Attribute causes type lookup to fail. Regression.

Responsible-Changed-From-To: unassigned->jason
Responsible-Changed-By: jason
Responsible-Changed-When: Fri Feb  1 03:57:01 2002
Responsible-Changed-Why:
    mine
State-Changed-From-To: analyzed->closed
State-Changed-By: jason
State-Changed-When: Fri Feb  1 03:57:01 2002
State-Changed-Why:
    Fixed for 3.0.4 and 3.1

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=3395

Re: c++/3395: Attribute causes type lookup to fail. Regression.

[lerdsuwa]

Synopsis: Attribute causes type lookup to fail. Regression.

State-Changed-From-To: open->analyzed
State-Changed-By: lerdsuwa
State-Changed-When: Sun Aug 12 07:45:37 2001
State-Changed-Why:
    Confirmed.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view&pr=3395&database=gcc

Re: c++/3395: Attribute causes type lookup to fail. Regression.

[rodrigc]

Synopsis: Attribute causes type lookup to fail. Regression.

State-Changed-From-To: feedback->open
State-Changed-By: rodrigc
State-Changed-When: Thu Jul 12 05:08:27 2001
State-Changed-Why:
    Code provided.
    Confirmed.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view&pr=3395&database=gcc

Re: c++/3395: Attribute causes type lookup to fail. Regression.

[rodrigc]

Synopsis: Attribute causes type lookup to fail. Regression.

State-Changed-From-To: open->feedback
State-Changed-By: rodrigc
State-Changed-When: Wed Jul 11 18:20:42 2001
State-Changed-Why:
    Your attachment contains no code.
    Can you resend the testcase which causes the compiler
    to crash?

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view&pr=3395&database=gcc