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I'm hunting some memoryleaks and I use FastMM in FullDebugMode to get event logs. This works pretty fine, but the stacktrace is...not very nice at all.

A short example:

This block was allocated by thread 0x25F8, and the stack trace (return addresses) at the time was:
4081E8 [FastMM4.pas][FastMM4][_ZN7Fastmm411DebugGetMemEx][8737]
4086A5 [FastMM4.pas][FastMM4][_ZN7Fastmm413DebugAllocMemEx][9019]
F0D820 [_ZN6System8AllocMemEx]
F18A0D [_ZN6System8TMonitor6CreateEv]
F18EEB [_ZN6System8TMonitor10GetMonitorEPNS_7TObjectE]
10AE265 [_ZN6System7Classes16CheckSynchronizeEi]
54CAC7 [Vcl.Forms.pas][Vcl.Forms][_ZN3Vcl5Forms12TApplication4IdleERK6tagMSG][11044]
54B598 [Vcl.Forms.pas][Vcl.Forms][_ZN3Vcl5Forms12TApplication13HandleMessageEv][10473]
54BA24 [Vcl.Forms.pas][Vcl.Forms][_ZN3Vcl5Forms12TApplication3RunEv][10611]
566719 [ServerRunner.pas][ServerRunner][_ZN12Serverrunner9RunServerEv][113]

This is not easy readable for me. I like that unit name is in square backets, but what did happen to methods names? I understand there is fully qualified name of the method with it's arguments types. But what is the mess (like _ZN3, 5, 12, 3, Ev) injected into it?

Stefan Glienke
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Jan Drozen
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  • Are you using runtime packages? And what stack tracing library is in use? – David Heffernan Aug 30 '16 at 14:10
  • See https://en.wikipedia.org/wiki/Name_mangling - how is this question related to Spring4D? – Stefan Glienke Aug 30 '16 at 14:14
  • @StefanGlienke: thank you. This is not tightly bound to Spring4D. I decided to tag this question to S4D (sorry?) because it's used in the project the stacktrace has been taken from and the second reason is the S4D community is for me more reliable (and especially you as the master :)). – Jan Drozen Sep 01 '16 at 15:14

1 Answers1

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_ZN3, 5, 12, 3, Ev
This is called name mangling.

Because it is possible to overload 2 functions with the same name (if using different parameters) the compiler needs some way to tell them apart.
The way this is done is by encoding the parameters in a vendor specific way and adding these codes to the method name.

See this question on SO: Delphi - unmangle names in BPL's

Delphi comes with a utility called tdump.exe and tdump64.exe that can decode the mangled names for you.
Someone even wrote a ruby gem for it. 

tdump -e <name_of_exe>

Will do the trick and display all unmangled names.

Here's some more reading: http://www.int0x80.gr/papers/name_mangling.pdf

If you're willing to invest then MadExcept unmangles the names for you.

Community
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Johan
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  • Thank you for your response! But the tdup as well as the (old) solution on SO does not work for me. However it pointed me to the right way. The name_mangling paper is superb. – Jan Drozen Sep 01 '16 at 15:10