You can use the windbg command !lmi mydll.dll
So for ntdll.dll the image name will display the path:
:004> !lmi ntdll
Loaded Module Info: [ntdll]
Module: ntdll
Base Address: 00000000776f0000
Image Name: C:\Windows\SYSTEM32\ntdll.dll
Machine Type: 34404 (X64)
Time Stamp: 51fb164a Fri Aug 02 03:15:38 2013
Size: 1a9000
CheckSum: 1a9bda
Characteristics: 2022 perf
Debug Data Dirs: Type Size VA Pointer
CODEVIEW 22, 101268, 100668 RSDS - GUID: {400F215C-54DA-4047-88F8-4F5C50491495}
Age: 2, Pdb: ntdll.pdb
CLSID 4, 101264, 100664 [Data not mapped]
Image Type: FILE - Image read successfully from debugger.
C:\Windows\SYSTEM32\ntdll.dll
Symbol Type: PDB - Symbols loaded successfully from symbol server.
C:\Program Files\Windows Kits\8.0\Debuggers\x64\sym\ntdll.pdb\400F215C54DA404788F84F5C504914952\ntdll.pdb
Load Report: public symbols , not source indexed
C:\Program Files\Windows Kits\8.0\Debuggers\x64\sym\ntdll.pdb\400F215C54DA404788F84F5C504914952\ntdll.pdb
This is a bit verbose however.
Thanks to @SeanCline who pointed out the undocumented command !itoldyouso
which does the same thing as !chksym
0:030> !itoldyouso ntdll
C:\Windows\SYSTEM32\ntdll.dll
Timestamp: 51FB164A
SizeOfImage: 1A9000
pdb: ntdll.pdb
pdb sig: 400F215C-54DA-4047-88F8-4F5C50491495
age: 2
Loaded pdb is C:\Program Files\Windows Kits\8.0\Debuggers\x64\sym\ntdll.pdb\400F215C54DA404788F84F5C504914952\ntdll.pdb
ntdll.pdb
pdb sig: 400F215C-54DA-4047-88F8-4F5C50491495
age: 2
MATCH: ntdll.pdb and C:\Windows\SYSTEM32\ntdll.dll
It is still pretty verbose, you save a few lines.
!itoldyouso
. – Kiwanis