[Issue 1121] New: Assertion codegen issue with templated function

April 10, 2007
Posted by d-bugmail
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http://d.puremagic.com/issues/show_bug.cgi?id=1121

           Summary: Assertion codegen issue with templated function
           Product: D
           Version: 1.010
          Platform: PC
        OS/Version: Windows
            Status: NEW
          Keywords: wrong-code
          Severity: critical
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla@digitalmars.com
        ReportedBy: jarrett.billingsley@gmail.com


Weirdest.  Bug.  Ever.

[test.d]------------------------
module test;

import mod;
import std.stdio;

void main()
{
        foo();
        func!(void)();
}
--------------------------------

[mod.d]-------------------------
module mod;

void foo()
{
        assert(false, "GO");
}

public void func(T)()
{
        assert(false, "Blah");
}
--------------------------------

Command line:

C:\dmd\proj\MiniDDebug\minid>dmd test.d mod.d C:\dmd\bin\..\..\dm\bin\link.exe test+mod,,,user32+kernel32/noi;

C:\dmd\proj\MiniDDebug\minid>test
Error: AssertError Failure GO(5) GO


Notice that the filename reported for the assert error is the same as the error message instead of "mod.d".  If you look at the disassembly for that "GO!" assert, it's something like this:

0040204B   push        5
0040204D   push        dword ptr ds:[40F0ECh]
00402053   push        dword ptr ds:[40F0E8h]
00402059   push        dword ptr ds:[40F0ECh]
0040205F   push        dword ptr ds:[40F0E8h]
00402065   call        __d_assert_msg (004022ac)

First it pushes the line number, then what should be the filename pointer and length, and then the message pointer and length.  The message pointer and length are correct, but the filename pointer and length are not right (in this case, it passes the same pointers and length as for the message).  The filename pointer and length passed also depend on the amount of code and constants in the executable, resulting in various outputs for this program (such as plain old access violations, or "AssertError out of memory" errors if the length passed is gigantic, or "4invalid UTF-8 sequence" errors when it tries to print out garbage).

However, it's only foo() whose assert is messed up.  func()'s assert works
fine.

Some other interesting aspects.  The following make the problem disappear:

- Removing either assert.
- Removing either assert message (but leaving the condition).
- Declaring foo, func, or both in test.d (both functions have to be declared in
mod.d for the problem to happen).
- Removing foo.

I.. just don't know.


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