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digitalmars.D.bugs - [Issue 1508] New: dmd/linux template symbol issues

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=1508

           Summary: dmd/linux template symbol issues
           Product: D
           Version: 1.021
          Platform: PC
        OS/Version: Windows
            Status: NEW
          Keywords: link-failure
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla digitalmars.com
        ReportedBy: braddr puremagic.com


I think I've reduced this as much as I can, sorry, it's four files.

main.d
----
module main;
void main() {}
----

a.d
----
module a;

private import c;

interface I
{
    void anything();
}

class A : I
{
    private C!(char) c;
    this() { c = new C!(char) (); }
    void anything() {}
}
----

b.d
----
module b;

private import c;

class B
{
    private C!(char) c;
    this() { c = new C!(char); }
}
----

c.d
----
module c;

class C(T)
{
    void foo() { }
} 
----

build instructions:
$ for x in a b c d main; do dmd -c $x; done
$ gcc main.o b.o a.o c.o -o main -m32 -Xlinker
-L/home/braddr/sandbox/d/dmd/1.021/dmd/bin/../lib -lphobos -lpthread -lm

error message: `.gnu.linkonce.t_D1c8__T1CTaZ1C3fooMFZv' referenced in section
`.data' of a.o: defined in discarded section
`.gnu.linkonce.t_D1c8__T1CTaZ1C3fooMFZv' of a.o

$ echo "_D1c8__T1CTaZ1C3fooMFZv" | ../../demangle/demangle 
void c.C!(char).C.foo(void*)

$ nm a.o | ../../demangle/demangle 
00000060 D Z a.__ModuleInfo
00000000 T class a.A a.A._ctor(void*)
0000005c R Z a.A.__init
00000070 R Z a.A.__vtbl
00000000 D Z a.A.__Class
00000000 T void a.A.anything(void*)
00000004 R Z a.I.__Interface
00000000 T void c.C!(char).C.foo(void*)
00000000 D Z c.C!(char).C.__init
00000000 D Z c.C!(char).C.__vtbl
00000000 D Z c.C!(char).C.__Class
         U Z Object.__Class
         U int object.Object.opCmp(class Object, void*)
         U void object.Object.print(void*)
         U uint object.Object.toHash(void*)
         U int object.Object.opEquals(class Object, void*)
         U char[] object.Object.toString(void*)
         U Z ClassInfo.__vtbl
         U void invariant._d_invariant(class Object)
         U _Dmodule_ref
0000000c t _TMP0
         U _d_newclass
00000000 t gcc2_compiled.

$ nm b.o | ../../demangle/demangle  
00000048 D Z b.__ModuleInfo
00000000 T class b.B b.B._ctor(void*)
00000010 R Z b.B.__init
00000020 R Z b.B.__vtbl
00000000 D Z b.B.__Class
00000000 T void c.C!(char).C.foo(void*)
00000000 D Z c.C!(char).C.__init
00000000 D Z c.C!(char).C.__vtbl
00000000 D Z c.C!(char).C.__Class
         U Z Object.__Class
         U int object.Object.opCmp(class Object, void*)
         U void object.Object.print(void*)
         U uint object.Object.toHash(void*)
         U int object.Object.opEquals(class Object, void*)
         U char[] object.Object.toString(void*)
         U Z ClassInfo.__vtbl
         U void invariant._d_invariant(class Object)
         U _Dmodule_ref
         U _d_newclass
00000000 t gcc2_compiled.

$ nm c.o | ../../demangle/demangle  
00000000 D Z c.__ModuleInfo
00000000 T Z c.__array
00000000 T void c.__assert(int)
         U _Dmodule_ref
00000008 r _TMP0
         U _d_array_bounds
         U _d_assert
00000000 t gcc2_compiled.


--
Sep 16 2007
next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=1508






$ nm a.o | ../../../demangle/demangle  
00000000 T class a.A a.A._ctor(void*)
00000014 R Z a.A.__init
00000028 R Z a.A.__vtbl
00000060 D Z a.A.__Class
00000026 T void a.A.anything(void*)
00000000 D Z a.I.__Interface
00000000 W void c.C!(char).C.foo(void*)
00000000 V Z c.C!(char).C.__init
00000000 V Z c.C!(char).C.__vtbl
00000000 V Z c.C!(char).C.__Class
         U Z Object.__Class
         U int object.Object.opCmp(class Object, void*)
         U void object.Object.print(void*)
         U uint object.Object.toHash(void*)
         U int object.Object.opEquals(class Object, void*)
         U char[] object.Object.toString(void*)
         U Z ClassInfo.__vtbl
         U void invariant._d_invariant(class Object)
         U __gdc_personality_v0
00000039 t __t12__D1a1A8anythingMFZv.1000
         U _d_newclass

$ nm b.o | ../../../demangle/demangle  
00000000 T class b.B b.B._ctor(void*)
00000010 R Z b.B.__init
00000020 R Z b.B.__vtbl
00000000 D Z b.B.__Class
00000000 W void c.C!(char).C.foo(void*)
00000000 V Z c.C!(char).C.__init
00000000 V Z c.C!(char).C.__vtbl
00000000 V Z c.C!(char).C.__Class
         U Z Object.__Class
         U int object.Object.opCmp(class Object, void*)
         U void object.Object.print(void*)
         U uint object.Object.toHash(void*)
         U int object.Object.opEquals(class Object, void*)
         U char[] object.Object.toString(void*)
         U Z ClassInfo.__vtbl
         U void invariant._d_invariant(class Object)
         U __gdc_personality_v0
         U _d_newclass

$ nm c.o | ../../../demangle/demangle 
<no symbols>
===========

A key difference is that gdc makes the template symbols weak and dmd doesn't.

One thing I failed to note in the original description, perturbing the order of
the .o's on the gcc line affects the results.  a before b works, b before a
doesn't.  When building with gdc, the order doesn't matter.. at least in the
orders I've tried.


--
Sep 16 2007
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=1508


bugzilla digitalmars.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |WORKSFORME





Cannot reproduce the problem on either Windows or Linux, with DMD 1.021 or
2.005. It may be a problem specific to the linker you have.


--
Oct 01 2007
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=1508


braddr puremagic.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
         Resolution|WORKSFORME                  |





Well, I absolutely can reproduce it, quite easily.  The version of gcc involved
is 4.2.1 and ld version 2.18.

Regardless of if the linker on your box digests it, from what I can tell, it's
not a legal construction and newer linkers are blocking it.  I'm not terribly
well versed in link-once vs weak symbols.  Time to do more reading I guess.

I just confirmed that I see this same problem with 2.004 as well as 1.021.


--
Oct 02 2007
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=1508


daniel.keep+d.puremagic.com gmail.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |daniel.keep+d.puremagic.com 
                   |                            |gmail.com





-------
I can confirm for DMD 1.021 running under Ubuntu 7.04 with latest packages.  It
appears that the only thing that matters is the relative order or a.o and b.o
to the linker; if b.o comes first, it will not link.  If a.o comes first, it
does link.

$ uname -a

GNU/Linux

$ gcc --version | head 1
gcc (GCC) 4.1.2 (Ubuntu 4.1.2-0ubuntu4)

$ dmd | head 1
Digital Mars D Compiler v1.021


--
Oct 02 2007
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=1508


moritzwarning web.de changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |moritzwarning web.de





I can confirm the problem, too.
(I used Tango, but that shouldn't matter)
When I link in this order "main.o a.o b.o c.o" - it works.

Debian unstable, (kernel 2.6.18-5-486)

$gcc --version | head 1
gcc (GCC) 4.1.3 20070831 (prerelease) (Debian 4.1.2-16)

$ dmd | head 1
Digital Mars D Compiler v1.022

$for x in a b c main; do dmd -c $x -I/opt/dmd/import ; done
$gcc main.o b.o a.o c.o -o main -m32 -Xlinker -L/opt/dmd/lib -lphobos -lpthread
-lm
`.gnu.linkonce.t_D1c8__T1CTaZ1C3fooMFZv' referenced in section `.data' of a.o:
defined in discarded section `.gnu.linkonce.t_D1c8__T1CTaZ1C3fooMFZv' of a.o


--
Oct 06 2007
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=1508


larsivar igesund.net changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |critical





I'm upping the severity - this issue requires intrusive workarounds that you
won't know is needed until linking an application barfs on some template
instance (of a template in a library) being discarded. Thus you have to modify
the library to fix your application. This is not acceptable, and makes DMD on
Linux hard to recommend beyond the most trivial tasks.


--
Nov 24 2007
prev sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=1508


bugzilla digitalmars.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|REOPENED                    |RESOLVED
         Resolution|                            |FIXED





Fixed dmd 1.024 and 2.008


--
Dec 04 2007