[Issue 311] New: Object files missing certain template instantiations

[d-bugmail at puremagic.com]

http://d.puremagic.com/issues/show_bug.cgi?id=311

           Summary: Object files missing certain template instantiations
           Product: D
           Version: 0.165
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Keywords: link-failure
          Severity: major
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla at digitalmars.com
        ReportedBy: oskar.linde at gmail.com


This is a very old infamous linking error that only appears when compiling the
modules separately on DMD, and always on GDC (that only supports one module at
a time compilation).

The smallest example I have found that triggers the bug is a three module
import chain a->b->c, where b instantiates a template in c, and the template in
c instantiates another template in c. The code for this other template never
gets written to any object file.

The workaround is to add an import c; in a.

---------- a.d ---------
import b;
//import c;

void main() { func(); }
---------- b.d ---------
import c;

void func()() { C(); }
---------- c.d ---------
void C(T=int)() { C!(double)(); }
------------------------

$ dmd -c a.d
$ dmd -c b.d
$ dmd -c c.d
$ dmd a.o b.o c.o
a.o: In function `_D1c8__T1CTiZ1CFZv':
a.d:(.gnu.linkonce.t_D1c8__T1CTiZ1CFZv+0x4): undefined reference to
`_D1c8__T1CTdZ1CFZv'

$ gdc a.d b.d c.d
/tmp/ccWsXe5T.o: In function `_D1c8__T1CTiZ1CFZv':
a.d:(.gnu.linkonce.t._D1c8__T1CTiZ1CFZv[_D1c8__T1CTiZ1CFZv]+0x7): undefined
reference to `_D1c8__T1CTdZ1CFZv'

$ dmd a.d b.d c.d
No error

Uncommenting the import c; in a.d makes the error go away.

I've not had the chance to verify this on any other platform than Linux.
DMD version 0.165 and GDC 0.17 was used.

/Oskar


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