CODEWITHSUNDEEP
c++visual-c++visual-studio-2012eigen
Muhammad Razib
Muhammad Razib

Reputation: 1305

is there a way in c++ not to generate debug information for a specific portion of a project?

I am recently working with Eigen library with visual C++ to solve a very large sparse linear system. Program works really fast in Release mode, but in Debug mode it takes hours to solve. I traced the timing, the program takes long time in "solve" function of Eigen. I want to build the project in debug mode as I need to debug a lot. Now is there a way not to generate debug information for Eigen portion? Or is there any other workaround for this problem?

Upvotes: 3

Views: 948

Answers (2)

mindriot
mindriot

Reputation: 5678

@MichaelWalz's answer is great, but I would like to add (as I have outlined in my comment to your question) that I strongly recommend not using Eigen in Debug mode.

Eigen is a highly efficient, yet very usable matrix library. It achieves its efficiency through a lot of “template magic”, using many layers of abstraction, and relies on the compiler's optimization stages to produce highly efficient code.

Debug mode usually implies that the compiler creates debug symbols, but also disables optimization. In GCC/clang, it is usually equivalent to -O0 -g; I believe in Visual Studio it corresponds to /O0 /DEBUG.

I recommend building all code that uses Eigen in a “release-with-debug-info” mode instead (what CMake calls CMAKE_BUILD_TYPE=RelWithDebInfo). This means that you allow the compiler to optimize, while still generating debug symbols. In GCC/clang, this is usually equivalent to -O2 -g; I believe in Visual Studio it corresponds to /O2 /DEBUG. Personally I have had very good experiences like this; IMHO it is only in very rare circumstances that you actually need to disable optimization completely.

Upvotes: 8

Jabberwocky
Jabberwocky

Reputation: 50883

You can disable debug information and enable code optimisation per file.

In the Solution Explorer right click on the file that contains the Eigen function, then chose Properties.

In the dialog that appears, choose the C/C++->Optimisation and chose the same options you have in Release mode.

Then choose C/C++->General and under "Debug Information Format" choose "None". But the presence of debug information has probably no influence on execution speed.

Upvotes: 6

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