c++/3394: Attribute in derived class crashes compiler. Regression.

c++/3394: Attribute in derived class crashes compiler. Regression.

[khan]

>Number:         3394
>Category:       c++
>Synopsis:       Attribute in derived class crashes compiler. Regression.
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          ice-on-legal-code
>Submitter-Id:   net
>Arrival-Date:   Sun Jun 24 21:06:02 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator:     Mumit Khan
>Release:        3.0
>Organization:
>Environment:
Cygwin, Mingw and other x86-win32 targets. Host independent.
>Description:

>How-To-Repeat:
Just compiling the provided testcase will trigger the problem.
>Fix:
Patch in the attached description.
>Release-Note:
>Audit-Trail:
>Unformatted:
----gnatsweb-attachment----
Content-Type: text/plain; name="gcc-bug1.txt"
Content-Disposition: inline; filename="gcc-bug1.txt"

The following code will crash the C++ front-end, a regression from
gcc-2.95.x.

struct
__attribute__((dllexport))
DllClassBase { };
 
struct
__attribute__((dllexport))
DllClass : public DllClassBase { };

The problem is quite simple -- when parsing the derived class DllClass,
the parameter passed to tree_low_cst in xref_basetypes has the type
TREE_LIST thanks to the attribute between class and name. 

Patch at end of this report. Hmmm ... should I send this separately to 
gcc-patches as well? 

(gdb) r -quiet -version dll-bug1.ii
Starting program: /homes/khan/src/win32/cygwin/BUILD/orig-gcc3/gcc/cc1plus
-quiet -version dll-bug1.ii
Breakpoint 1 at 0x400411d2: file exit.c, line 40.
Breakpoint 3 at 0x40040008: file ../sysdeps/generic/abort.c, line 55.
GNU CPP version 3.0 (cpplib) (80386, BSD syntax)
GNU C++ version 3.0 (i686-pc-cygwin)
        compiled by GNU C version 3.0.
 
Breakpoint 2, fancy_abort (
    file=0x8370ec0 "/home/khan/src/gnu/gcc-3.0/gcc/tree.c", line=3462,
    function=0x8371972 "tree_low_cst")
    at /home/khan/src/gnu/gcc-3.0/gcc/diagnostic.c:1760
1760      internal_error ("Internal compiler error in %s, at %s:%d",
(gdb) bt
#0  fancy_abort (file=0x8370ec0 "/home/khan/src/gnu/gcc-3.0/gcc/tree.c",
    line=3462, function=0x8371972 "tree_low_cst")
    at /home/khan/src/gnu/gcc-3.0/gcc/diagnostic.c:1760
#1  0x810e0fa in tree_low_cst (t=0x40174230, pos=1)
    at /home/khan/src/gnu/gcc-3.0/gcc/tree.c:3462
#2  0x806e814 in xref_basetypes (code_type_node=0x40174230,
name=0x40176100,
    ref=0x40175478, binfo=0x40174280)
    at /home/khan/src/gnu/gcc-3.0/gcc/cp/decl.c:12768
#3  0x80af0d5 in yyparse_1 () at /usr/lib/bison.simple:2409
#4  0x80fd26d in yyparse () at /home/khan/src/gnu/gcc-3.0/gcc/c-lex.c:158
#5  0x81026e3 in compile_file (name=0x844f2d7 "dll-bug1.ii")
    at /home/khan/src/gnu/gcc-3.0/gcc/toplev.c:2369
#6  0x81069c6 in main (argc=4, argv=0xbffff6e4)
    at /home/khan/src/gnu/gcc-3.0/gcc/toplev.c:4990
(gdb) up
#1  0x810e0fa in tree_low_cst (t=0x40174230, pos=1)
    at /home/khan/src/gnu/gcc-3.0/gcc/tree.c:3462
3462        abort ();
(gdb) up
#2  0x806e814 in xref_basetypes (code_type_node=0x40174230, name=0x40176100, ref=0x40175478, binfo=0x40174280)
    at /home/khan/src/gnu/gcc-3.0/gcc/cp/decl.c:12768
12768     enum tag_types tag_code = (enum tag_types) tree_low_cst (code_type_node, 1);
(gdb) p code_type_node
$1 = 0x40174230
(gdb) pt
 <tree_list 0x40174230
    purpose <tree_list 0x401741f4
        purpose <identifier_node 0x40170380 dllexport
            bindings <binding 0x40163f14 scope 0x40162000>>>
    value <integer_cst 0x4015e020 type <integer_cst 0x4015e020 0> constant 0>>


2001-06-22  Mumit Khan  <khan@nanotech.wisc.edu>

	* decl.c (xref_basetypes): Handle attributes between 'class' and 
	name.

Index: gcc/cp/decl.c
===================================================================
RCS file: /homes/khan/src/win32/cygwin/CVSROOT/gcc-3.0/gcc/cp/decl.c,v
retrieving revision 1.2
diff -u -3 -p -r1.2 decl.c
--- gcc/cp/decl.c	2001/06/21 04:44:06	1.2
+++ gcc/cp/decl.c	2001/06/22 15:15:12
@@ -12765,6 +12765,14 @@ xref_basetypes (code_type_node, name, re
   tree base;
 
   int i, len;
+
+  /* If we are called from the parser, code_type_node will sometimes be a
+     TREE_LIST.  This indicates that the user wrote
+     "class __attribute__ ((foo)) bar".  Extract the attributes so that
+     tree_low_cst doesn't crash.  */
+  if (TREE_CODE (code_type_node) == TREE_LIST)
+    code_type_node = TREE_VALUE (code_type_node);
+
   enum tag_types tag_code = (enum tag_types) tree_low_cst (code_type_node, 1);
 
   if (tag_code == union_type)

Re: c++/3394: Attribute in derived class crashes compiler. Regression.

[lerdsuwa]

Synopsis: Attribute in derived class crashes compiler. Regression.

State-Changed-From-To: open->analyzed
State-Changed-By: lerdsuwa
State-Changed-When: Sun Aug 12 07:44:01 2001
State-Changed-Why:
    Confirm.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view&pr=3394&database=gcc

Re: c++/3394: Attribute in derived class crashes compiler. Regression.

[rodrigc]

Synopsis: Attribute in derived class crashes compiler. Regression.

State-Changed-From-To: feedback->open
State-Changed-By: rodrigc
State-Changed-When: Thu Jul 12 05:07:13 2001
State-Changed-Why:
    Code provided.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view&pr=3394&database=gcc

Re: c++/3394: Attribute in derived class crashes compiler. Regression.

[rodrigc]

Synopsis: Attribute in derived class crashes compiler. Regression.

State-Changed-From-To: open->feedback
State-Changed-By: rodrigc
State-Changed-When: Wed Jul 11 18:22:37 2001
State-Changed-Why:
    Your attachment contains no code.
    Can you resend the attachment which contains
    the code which illustrates the crash?

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view&pr=3394&database=gcc