Debugging with JWasm/JWlink

[cinolt]

I'm trying to debug a program assembled and linked with JWasm/JWlink using the debugger WinDbg on the x86-64 Windows 7 platform. I assume that I need to include certain command-line options to enable debugging with symbols and the source code. This is how I compiled/linked my program:

jwasm -I\WinInc202\Include -Zd -Zi -win64 a.asm
jwlink form win pe libp \WinInc202\Lib\x64 d c ru win f a.obj

And this is the output I get:

JWasm v2.07a, Jul 21 2012, Masm-compatible assembler.
Portions Copyright (c) 1992-2002 Sybase, Inc. All Rights Reserved.
Source code is available under the Sybase Open Watcom Public License.
a.asm: 60 lines, 2 passes, 234 ms, 0 warnings, 0 errors
JWlink Version 1.9
Portions Copyright (c) 1985-2002 Sybase, Inc. All Rights Reserved.
Source code is available under the Sybase Open Watcom Public License.
loading object files
unknown reloc type 0 at .debug$S:7479
Error! E2015: file a.obj(a.asm): bad relocation type specified
unknown reloc type 0 at .debug$S:7567
Error! E2015: file a.obj(a.asm): bad relocation type specified
unknown reloc type 0 at .debug$S:8AEF
Error! E2015: file a.obj(a.asm): bad relocation type specified
unknown reloc type 0 at .debug$S:8C4D
Error! E2015: file a.obj(a.asm): bad relocation type specified
unknown reloc type 0 at .debug$S:A7C6
Error! E2015: file a.obj(a.asm): bad relocation type specified

It assembles fine but it gives the above error messages when linking. I appreciate any help.

[cinolt]

Also, here is the source code if needed:

;Windows 7 x86-64
;Compiled with "jwasm -I\WinInc202\Include -Zd -Zi -win64 a.asm"
option casemap:none
;WIN32_LEAN_AND_MEAN equ 1
include windows.inc
include winuser.inc
includelib kernel32.lib
includelib user32.lib
.const
ClassName db "aWinClass",0
AppName db "a",0
.data
.data?
ghWnd HWND ?
.code
WndProc proc hWnd:HWND,uMsg:UINT,wParam:WPARAM,lParam:LPARAM
    invoke DefWindowProc,hWnd,uMsg,wParam,lParam
    ret
WndProc endp
Start proc
    local hinst:HINSTANCE
    local wc:WNDCLASS
    int 3h
    mov wc.style,0
    mov rax,offset WndProc
    mov wc.lpfnWndProc,rax
    mov wc.cbClsExtra,NULL
    mov wc.cbWndExtra,NULL
    invoke GetModuleHandle,NULL
    mov hinst,rax
    mov wc.hInstance,rax
    invoke LoadIcon,NULL,IDI_APPLICATION
    mov wc.hIcon,rax
    invoke LoadCursor,NULL,IDC_ARROW
    mov wc.hCursor,rax
    mov wc.hbrBackground,COLOR_WINDOW+1
    mov wc.lpszMenuName,NULL
    mov rax,offset ClassName
    mov wc.lpszClassName,rax
    invoke RegisterClass,addr wc
    ;invoke CreateWindowEx,0,offset ClassName,offset AppName,WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,CW_USEDEFAULT,128,128,NULL,NULL,hinst,NULL
    ;mov ghWnd,rax
    ;invoke ShowWindow,rax,SW_SHOWNORMAL
    ;invoke UpdateWindow,rax
    ;invoke Sleep,2000
    invoke ExitProcess,0
Start endp
end Start

[japheth]

Symbolic debugging info for Win64 ( aka CodeView V8 ) isn't implemented yet.

It looks like jwasm tries to write the old CV4 info for 64-bit, but this is useless, because no linker will be able to handle it (including jwlink).

[cinolt]

Ah, that's a shame. Are there plans to implement symbolic debugging for Win64 any time soon?

[japheth]

> Are there plans to implement symbolic debugging for Win64 any time soon?

Yes, there are plans to implement it "any time soon". That's the good news. The not so good news is that the plans exist now for 2 years and virtually nothing has happened yet. The problem is: I don't need this feature - hence my interest is low.

[japheth]

> Symbolic debugging info for Win64 ( aka CodeView V8 ) isn't implemented yet.

This is only partially true. Codeview 8 debugging info isn't implemented, but this format isn't really required for 64-bit symbolic debugging. I tried with JWasm's CV4 info and WinDbg 6.12 and had no problems with symbolic debugging on 64-bit Windows 7.