Reduce exe file

Question

Using Delphi (or in general any tools, if exist of course), is it possible to reduce size of an exe file, removing all code that not is used but that is present there?
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Answer 1

Just to supplement what other's have written...

The smart linker will eliminate unused routines except under the following conditions:

• The unit has an initialization section - unfortunately many of the largest units in the RTL/VCL (Classes, SysUtils, Windows, Forms... to name a few) have initialization sections so if they are in your uses clause you get the whole enchilada linked into your code. Much of the code in the RTL/VCL could be refactored to reduce or eliminate this but it would break backward compatibility.

• The routine is part of a class and is marked as virtual or dynamic - If you instantiate and object in your code that has virtual or dynamic methods, those methods are linked into your executable whether you call them or not.

Additional steps to can take to reduce exe file size:

• Take advantage of form inheritance - If you have many similar forms, create a base form for them to inherit from. These child forms will only store properties that differ from the base form in their dfms. This can drastically reduce the size of your executable by eliminating redundant information in your dfms.

• Store any large graphics in external files and load them on demand - Splash screens, "skins", icon sets, etc. can really bloat the size of an exe. Delphi doesn't always store these files in the most efficient format when they're embedded in the exe.

• You can shave 10% - 30% off an exe's size by stripping certain unused data from the exe after its been compiled. There are third party tools that can do this but you can eliminate some of the cruft by setting appropriate PE header flags. Make sure you understand the implications of each flag before using it as some flags could make your exe unusable.

• Copy portions of the RTL/VLC into your own units - instead of including Classes or SysUtils in your uses clause, create an new unit and copy just the classes and functions you need into the unit. Then use it instead.

• Break code up into loadable modules - If you have multiple exes that reuse the same units you can make them smaller by using dlls or bpls rather than statically linking everything into the exes. A dll/bpl will only be loaded into memory once no matter how many exes need it.