CODEWITHSUNDEEP
c++windbgsymbolsdebug-symbols
igal k
igal k

Reputation: 1914

Windbg loads symbols from an altered location

Using the symbols window(CTRL + S), i have set WinDbg to load my symbols from a specific location.

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Now when i attach my debugger and try to view the stack window, it seems like symbols aren't really loaded properly.

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Now, when i use the !sym noisy command and .reload /f, i get the following info from the debugger:

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So, from the third picture, why is SYMSRV is even defined? and why is it adding the GUID prefix to the end of the file?

It would've worked if it wasn't that guid windbg adds to the path. What am i doing wrong.

EDIT: after reviewing the log furthermore, i see that the debugger attemps to load the symbol from the local drive.

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Upvotes: 1

Views: 694

Answers (1)

Thomas Weller
Thomas Weller

Reputation: 59513

There are several different formats in which symbols can be stored. These are 0-tier, 2-tier and 3-tier.

0-tier is basically a flat list of files, which is suitable if you have just built your program and all the PDBs are located in one folder. If you enter a local path like c:\path or server share like \\server, WinDbg should consider a 0-tier store layout, but might try others as well.

The problem is that you can only store one version of PDBs in a 0-tier store, which is why the 2-tier and 3-tier symbol stores exist. When symbols are added to such a store, it will consider the GUID, so it is possible to store several versions of the same program. 2- and 3-tier symbol stores should start with srv*. The exact difference between a 2-tier and a 3-tier store is explained in Channel 9 episode 87 and it's possible to convert a 2-tier store into a 3-tier store.

Do not confuse the srv* symbol path syntax with the SYMSRV: debug output. IMHO the SYMSRV: is just a debug message of the symsrv.dll, so nothing to worry about.

The truth about loading symbols can only be monitored with Process Monitor. Not all location where WinDbg searches for symbols are logged, even in the noisy mode.

In addition to the symbol path, DLLs contain a reference to the local path of the PDB and WinDbg will consider this path, independent of the symbol path settings.

Upvotes: 0

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