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?
(for example, a function or procedure that is present but is never called).
I remember that with Pascal, using unit (without objects) the compiler includes only procedures and functions that are really used and will strip out non-used routines in a unit from the final exe.

With Object-pascal, I remember that in Delphi 1 all members of a object are included in the exe;
Has something has changed since than till Delphi-XE2?

Answer 1

If you aren't using RTTI you can add this to the top of your .dpr file (immediately after program) to remove the extra RTTI information:

{$IFOPT D-}{$WEAKLINKRTTI ON}{$ENDIF}
{$RTTI EXPLICIT METHODS([]) PROPERTIES([]) FIELDS([])}

If you want to strip it out of all the RTL/VCL units then you'd need to include those in your project file too so that the settings above could take effect. I don't think I would recommend doing that since I don't believe the reduction in executable size is worth the complications of compiling your own RTL/VCL.

You can also add the following, again somewhere in your .dpr file:

{$SetPEFlags IMAGE_FILE_RELOCS_STRIPPED}

This will strip the relocation information which is not needed in a .exe. Don't add this to a DLL or package!

Answer 2

reduce the application EXE size - excellent article

(Taken from the link above)

Generally, EXE files created with Delphi are larger than EXE files created with another programming language. The reason is the VCL. (Sure, VCL has many advantages...)

There are several ways to reduce a EXE's size:

01) Use a EXE-Packer (UPX, ASPack,...)-UPX

02) Use KOL.

03) Write your application without VCL

04) Use the ACL (API Controls Library)

05) Use StripReloc.

06) Deactivate remote debugging information and TD32.

07) You might want to put code in a dll.

08) Don't put the same images several times on a form. Load them at runtime.

09) Use compressed images (JPG and not BMP)

10) Store less properties in DFM files

Answer 3

If your aim is to reduce the size of your executable, you can use a tool which compress it and allow to execute it as it was not compress.. (=not a zip)

For instance, you can check UPX which works nicely with delphi programs.

Answer 4

Delphi has a smart linking option that is ON by default if I remember correctly. It does exactly what you describe. Only used functions and data are linked to your exe. If you need further size compression you can try one of the many "exe compressor" programs out there.

Answer 5

Yet another option: Use WinRar to create a Setup file (yes, WinRar can do that). WinRar can automatically execute an EXE file once the unpacking is done.

WinRar has a superior compression ratio. One of the reasons is that it will merge all your files as a single file and then will start the compression, while ZIP (and other similar not-so-sophisticated compressors) will compress each file individually and merge them in a large file after the compression.

This give RAR's algorithm a better chance to find duplicate data among your files.

Plus, WinRar is less complicated than other installers (minus: it does not offer an uninstaller also, but that it is easy to fix with your own program).

Disclaimer: I am not affiliated with WinRAR.

Answer 6

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.