KnowledgeBase Archive

An Archive of Early Microsoft KnowledgeBase Articles

View on GitHub

Q179269: HOWTO: Use Source Profiler to Profile Dynamic-Link Libraries

Article: Q179269
Product(s): Microsoft Programming Utilities
Version(s): winnt:2.0,2.1,2.2,4.0,4.0a,4.1,4.2,4.2b,5.0,6.0
Operating System(s): 
Keyword(s): kbcode kbVC200 kbVC210 kbVC220 kbVC400 kbVC410 kbVC420 kbVC500 kbVC600
Last Modified: 04-MAY-2001

-------------------------------------------------------------------------------
The information in this article applies to:

- The Source Profiler, included with:
   - Microsoft Visual C++, 32-bit Editions, versions 2.0, 2.1, 2.2, 4.0, 4.0a, 4.1, 4.2b 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 4.2 
   - Microsoft Visual C++, 32-bit Professional Edition, version 4.2 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 5.0 
   - Microsoft Visual C++, 32-bit Professional Edition, version 5.0 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 6.0 
   - Microsoft Visual C++, 32-bit Professional Edition, version 6.0 
   - Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
-------------------------------------------------------------------------------

SUMMARY
=======

The Microsoft Visual C++ Help discusses two ways to profile a dynamic-link
library (DLL), but it does not indicate when to use each example. This article
describes a general-purpose method of profiling DLLs.

MORE INFORMATION
================

The first part of the Help on profiling a DLL describes the use of self-
profiling DLLs, using the PREP option /OM. Self-profiling DLLs are not
necessary, except when profiling DLLs that are dynamically loaded using the
LoadLibrary instruction. Use the following batch file example (name it
Profdll.bat) to profile a single DLL, accessed with LoadLibrary. Profdll.bat
profiles a DLL with the assumption that the .exe file has not been prepared for
profiling.

Sample Batch File
-----------------

  COPY %1.dll save
  PREP /OM %1.dll
  COPY %1._ll %1.dll
  PROFILE /I %1 /O %1 %2 %3 %4 %5 %6
  COPY save %1.dll
  PREP /M %1
  PLIST %1

If you have a main program (for example, Hearts.exe) that uses a DLL (for
example, Cards.dll) and you want to profile only the DLL, you can run the batch
file as:

  PROFDLL cards hearts

Note that the command above generates a warning message that the main program has
not been prepared for profiling. You can ignore this message.

The second example batch file in the Help shows how to profile multiple DLLs as
well as the calling executable. This example profiles an executable named
"wingame" and two DLLs named "aliens" and "hiscore":

Sample Batch File
-----------------

  PREP /OM /FC wingame.exe aliens.dll hiscore.dll
  PROFILE wingame.exe
  PREP /M  wingame
  PLIST wingame >wingame.out

This method is most effective when the DLLs are loaded at run time, through the
use of an import library. The Source Profiler, however, does not report any data
for a dynamically loaded DLL if you use function profiling. The maximum number
of DLLs that can be profiled this way is:

- 7 for Visual C++, versions 2.x and 4.x

- 15 for Visual C++, version 5.0

- 31 for Visual C++, version 6.0

When you combine import DLLs and LoadLibrary DLLs in a single executable, the
Help is unclear about how to handle this. The first method provides information
about a single DLL, and the second method does not work for all types of
profiling.

You must combine these two methods when considering larger, more complex
projects. First, create self-profiling objects for all items in the profile:

  PREP /OM /FT myfile.exe import1.dll loadlib1.dll ...

where "myfile.exe" is the executable program, "import1.dll" is a DLL called
through an import library, and "loadlib1.dll" is a DLL called through the
LoadLibrary and GetProcAddress functions.

Next, use the first method and copy the _LL files over all DLLs loaded using
LoadLibrary:

  copy loadlib1.dll loadlib1.tmp
  copy loadlib1._ll loadlib1.dll

The rest of the procedure is the same as for most profiles:

  PROFILE myfile.exe
  PREP /M myfile
  PLIST myfile >> profile.out

Putting it all together, you can generalize the process as follows:

1. PREP /OM /[profiling type] exename dllname1 dllname2 ... where [profiling
  type] is either /FT, /FC, /FV, /LC, or /LV

2. If a DLL is loaded using LoadLibrary, copy the _LL file over the existing
  .dll file. You should backup the original DLL, just in case:

     copy dllname.dll dllname.tmp
     copy dllname._ll dllname.dll

  where "dllname" is the name of the DLL accessed using LoadLibrary. Note that
  the _LL file is not created for /LC and /LV profiling types.

3. Run the remaining PROFILE, PREP, and PLIST steps as outlined above and in the
  Visual C++ Help.

You should not try to profile a DLL that may have been loaded at run time and
dynamically in the same application.

REFERENCES
==========

Visual C++, version 5.0; Profiling DLLs from a Batch File; Profiling Multiple
.dll and .exe Files

URL: mk:@ivt:vccore/F33/D36/S4D19E.HTM URL: mk:@ivt:vccore/F33/D36/S4D19F.HTM

Visual C++, versions 2.0, 2.1, 2.2, 4.0, 4.0a, 4.1, 4.2, 4.2b; search on:
"Profiling DLLs from a batch file"; "Profiling multiple .dll and .exe files"

Additional query words: Profile.dll _LL _XE line profiling

======================================================================
Keywords          : kbcode kbVC200 kbVC210 kbVC220 kbVC400 kbVC410 kbVC420 kbVC500 kbVC600 
Technology        : kbVCsearch kbAudDeveloper kbSProfilerSearch kbVC32bitSearch kbSProfiler100
Version           : winnt:2.0,2.1,2.2,4.0,4.0a,4.1,4.2,4.2b,5.0,6.0
Issue type        : kbhowto

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.