File size and smartlinking: what changed

Old	New		Line
1	1		This article is a work in progress about executable size and smartlinking on Lazarus. Feel free to contribute.
2	2
3	3		## Introduction
4	4
5	5		In Free Pascal, "smartlinking" is removing unused code and variables from the final executable. This is done during the linking stage, when the executable is written using the object files created by the compiler earlier.
6	6
7	7		## Case study 1 in Windows
8	8
9	9		This study was conducted on the 8th of February 2006 because a Lazarus fully compiled with Smartlinking was Released (version 0.9.12). It intends to establish the relationship between the varying results below with different Lazarus and Free Pascal versions as well as with Smartlinking and without.
10	10
11	11		The Variables being studied are:
12	12
13	13		- Executable size after strip
14	14		- Executable size after strip and UPX
15	15		- Linking time
16	16
17	17		Compile time isn´t considered here because it´s too similar on all configurations and much less significant than the link time.
18	18
19	19		Executable size without strip isn´t included. Notice that strip was used always from command line with the command:
20	20
21	21		strip --strip-all magnifier.exe
22	22
23	23		The program being compiled is the Virtual Magnifying Glass. The source and binaries for this program are freely available for download on: <http://magnifier.sourceforge.net>
24	24
25	25		About the linking time please note that the utilized computer is 3.2GHz Pentium 4 with Intel motherboard and dual core processor and 512MB of RAM.
26	26
27	27		Results
28	28
29	29		The utilized OS is Windows XP and the 0.9.13 versions are from the same date when 0.9.12 was release. The comparison took place using the following software configurations:
30	30
31	31		- Lazarus 0.9.12 available [here](http://sourceforge.net/project/showfiles.php?group_id=89339). Free Pascal 2.0.2 that comes with the installer. LCL and RTL are smartlinked. Refered from now on as simply 0.9.12.
32	32
33	33		- Lazarus 0.9.13 downloaded from Subversion from the same date. Free Pascal 2.0.2 installed separately. The LCL is not smartlinked. Refered from now on as simply 0.9.13 + 2.0.2.
34	34
35	35		- Lazarus 0.9.13 snapshot. Free Pascal 2.1 that comes with the installer. The LCL is not smartlinked. Refered from now on as simply 0.9.13 + 2.1.
36	36
37	37		- Lazarus 0.9.13 snapshot. Free Pascal 2.1 that comes with the installer. The LCL is smartlinked. Refered from now on as simply 0.9.13 + 2.1 + SL.
38	38
39	39		\| \| 0.9.12 \| 0.9.13 + 2.0.2 \| 0.9.13 + 2.1 + SL \| 0.9.13 + 2.1 \|
40	40		\|----\|----\|----\|----\|----\|
41	41		\| File Size after strip (in bytes) \| 1,108,480 \| 1,587,712 \| 1,425,408 \| 1,649,152 \|
42	42		\| File Size after UPX (in bytes) \| 318,976 \| 438,272 \| 388,608 \| 454,144 \|
43	43		\| Linking time \| 15 seconds \| 5 seconds \| 45 seconds \| 10 seconds \|
44	44
45		-	~~<figure>~~
46		-	~~<img src="OuptutFileSizesComparisonChart.png" title="OuptutFileSizesComparisonChart.png" />~~
47		-	~~<figcaption>OuptutFileSizesComparisonChart.png</figcaption>~~
48		-	~~</figure>~~
	45	+	![](/wiki-images/a/a1/OuptutFileSizesComparisonChart.png)
49	46
50	47		Conclusion
51	48
52	49		The 0.9.13 snapshot from the 8th of February 2006 features a unstable compiler from the 2.1 branch, which can cause the bigger executables and slower linking time as compared to the other versions.
53	50
54	51		The 0.9.12 version has the best file size of all, both with UPX and without, showing that Smartlinking really can diminish the file size in Windows. This, however, does not come without a cost, and the cost is linking time, which is about 3 times higher then without smartlinking.
55	52
56	53		The 0.9.12 version already comes fully configured for Smartlinking on Windows and no extra configuration is needed. This was not the case on previous releases.
57	54
58	55		## Remove unused functions in a class
59	56
60	57		Q: If a virtual method of a class is not used at all in the programm will the compiler remove it from the executable ?
61	58
62	59		A: If you use FPC 2.3.1 with whole-program optimization and the compiler can prove that it is never callable: yes. See [[Whole Program Optimization]] for more information. In case this is in relation to the thread on the Lazarus list about the big executables: note that it has only a limited effect on Lazarus programs, because almost all linked LCL code can potentially be executed (due to the way the LCL is constructed). In fact, I think most savings there come from making a number of virtual method calls non-virtual, rather than from throwing away unreachable code.
63	60
64	61		The internal linker can also do it (only throwing away virtual method calls, not turning virtual method calls into static ones), but only on Windows platforms. It is however not currently enabled in the compiler, because the changes break the external linker. It should therefore be turned into a command line option (along with a check that produces an error if you try to link a unit compiled with the option using the external linker), but that hasn't been done yet.
65	62
66	63		Q: How can the compiler determine that a virtual method is unused at all,
67	64
68	65		A: If you have a class hierarchy TBase-\>TDerived1-\>TDerived2 with a virtual method called "vmethod", and nowhere in the program there is a call to vmethod, then it is unused. Or if it is only called using TDerived2 instances, then if the linker does not find any direct references to TDerived1.vmethod or TBase.vmethod (e.g., via "inherited" calls from TDerived2 methods), it knows that the VMT entries for "vmethod" in TDerived1 and TBase can be set to nil.
69	66
70	67		## Bytes Used
71	68
72	69		Here's a layout by pascal units in bytes used for code. The size is based on Dwarf2 information generated. Doesn't include resources size used by a unit.
73	70
74	71		The project is a single form application (no additional controls used). Lazarus used is a Trunk version of 23 Jan 2020.
75	72
76	73		No optimization was used during compilation.
77	74
78	75		\| Size \| Lib \| Package \| Category \| File name \|
79	76		\|--------\|------\|----------\|----------\|--------------------------------\|
80	77		\| 238704 \| lcl \| base \| \| controls.pp \|
81	78		\| 144064 \| lcl \| base \| \| graphics.pp \|
82	79		\| 111280 \| lcl \| ws \| \| win32/win32int.pp \|
83	80		\| 106880 \| lcl \| base \| \| forms.pp \|
84	81		\| 98000 \| rtl \| rtl \| \| system.pp \|
85	82		\| 94432 \| lcl \| base \| \| intfgraphics.pas \|
86	83		\| 90352 \| lcl \| base \| \| comctrls.pp \|
87	84		\| 90224 \| rtl \| rtl \| \| classes.pp \|
88	85		\| 59552 \| lcl \| base \| \| stdctrls.pp \|
89	86		\| 51888 \| lcl \| base \| \| interfacebase.pp \|
90	87		\| 50336 \| rtl \| rtl \| \| ../win/sysutils.pp \|
91	88		\| 37728 \| lcl \| base \| \| imglist.pp \|
92	89		\| 35456 \| rtl \| rtl \| \| rtl-objpas/src/inc/variants.pp \|
93	90		\| 33232 \| lcl \| lazutils \| \| lazutf8.pas \|
94	91		\| 31456 \| lcl \| base \| \| extctrls.pp \|
95	92		\| 30912 \| fcl \| image \| \| fcl-image/src/fpreadtiff.pas \|
96	93		\| 30816 \| lcl \| ws \| \| win32/win32wscomctrls.pp \|
97	94		\| 30800 \| lcl \| ws \| \| win32/win32wsmenus.pp \|
98	95		\| 28832 \| lcl \| base \| \| menus.pp \|
99	96		\| 25984 \| lcl \| base \| \| maskedit.pp \|
100	97		\| 24480 \| rtl \| rtl \| \| rtl-objpas/src/win/varutils.pp \|
101	98		\| 24048 \| lcl \| base \| \| dialogs.pp \|
102	99		\| 23632 \| fcl \| json \| \| fcl-json/src/fpjson.pp \|
103	100		\| 23456 \| lcl \| ws \| \| win32/win32wsstdctrls.pp \|
104	101		\| 23408 \| lcl \| base \| \| lclintf.pas \|
105	102		\| 18448 \| lcl \| base \| \| lresources.pp \|
106	103		\| 17904 \| lcl \| lazutils \| \| textstrings.pas \|
107	104		\| 16736 \| fcl \| image \| \| fcl-image/src/fpcanvas.pp \|
108	105		\| 16544 \| lcl \| lazutils \| \| graphtype.pp \|
109	106		\| 13408 \| lcl \| base \| \| themes.pas \|
110	107		\| 13168 \| lcl \| ws \| \| win32/win32proc.pp \|
111	108		\| 13136 \| fcl \| image \| \| fcl-image/src/pixtools.pp \|
112	109		\| 13088 \| lcl \| lazutils \| \| lazloggerbase.pas \|
113	110		\| 12368 \| lcl \| lazutils \| \| laz_avl_tree.pp \|
114	111		\| 11872 \| fcl \| image \| \| fcl-image/src/fpimage.pp \|
115	112		\| 11776 \| lcl \| base \| \| actnlist.pas \|
116	113		\| 11488 \| lcl \| base \| \| buttons.pp \|
117	114		\| 10576 \| rtl \| debug \| \| ../inc/heaptrc.pp \|
118	115		\| 10544 \| lcl \| ws \| \| win32/win32wsbuttons.pp \|
119	116		\| 10464 \| rtl \| rtl \| \| ../objpas/typinfo.pp \|
120	117		\| 9744 \| fcl \| image \| \| fcl-image/src/fpreadpng.pp \|
121	118		\| 9696 \| lcl \| base \| \| graphmath.pp \|
122	119		\| 9536 \| lcl \| lazutils \| \| lazlogger.pas \|
123	120		\| 9424 \| lcl \| lazutils \| \| lazfileutils.pas \|
124	121		\| 9296 \| lcl \| base \| \| buttonpanel.pas \|
125	122		\| 9248 \| fcl \| image \| \| fcl-image/src/fpwritetiff.pas \|
126	123		\| 8864 \| lcl \| base \| \| clipbrd.pp \|
127	124		\| 8768 \| lcl \| ws \| \| win32/win32extra.pas \|
128	125		\| 8768 \| fcl \| jpeg \| \| pasjpeg/src/jquant2.pas \|
129	126		\| 8720 \| fcl \| jpeg \| \| pasjpeg/src/jdmarker.pas \|
130	127		\| 8160 \| fcl \| image \| \| fcl-image/src/fpwritepng.pp \|
131	128		\| 8016 \| fcl \| image \| \| fcl-image/src/fpwritebmp.pp \|
132	129		\| 7792 \| fcl \| zlib \| \| paszlib/src/trees.pas \|
133	130		\| 7648 \| fcl \| zlib \| \| paszlib/src/zdeflate.pas \|
134	131		\| 7536 \| fcl \| image \| \| fcl-image/src/ellipses.pp \|
135	132		\| 7472 \| lcl \| ws \| \| win32/win32wsforms.pp \|
136	133		\| 7456 \| fcl \| image \| \| fcl-image/src/fpreadbmp.pp \|
137	134		\| 7328 \| lcl \| ws \| \| win32/win32themes.pas \|
138	135		\| 6880 \| fcl \| jpeg \| \| pasjpeg/src/jdcoefct.pas \|
139	136		\| 6864 \| lcl \| base \| \| lclproc.pas \|
140	137		\| 6624 \| lcl \| lazutils \| \| lazutf16.pas \|
141	138		\| 6400 \| lcl \| ws \| \| win32/win32wscontrols.pp \|
142	139		\| 6240 \| fcl \| zlib \| \| paszlib/src/infblock.pas \|
143	140		\| 5920 \| lcl \| base \| \| lclrescache.pas \|
144	141		\| 5792 \| fcl \| image \| \| fcl-image/src/fpreadjpeg.pas \|
145	142		\| 5728 \| fcl \| image \| \| fcl-image/src/fppixlcanv.pp \|
146	143		\| 5680 \| fcl \| ws \| \| win32/win32wsspin.pp \|
147	144		\| 5648 \| lcl \| lazutils \| \| maps.pp \|
148	145		\| 5632 \| lcl \| ws \| \| win32/win32wsimglist.pp \|
149	146		\| 5568 \| fcl \| jpeg \| \| pasjpeg/src/jchuff.pas \|
150	147		\| 5520 \| fcl \| jpeg \| \| pasjpeg/src/jmemmgr.pas \|
151	148		\| 5392 \| fcl \| jpeg \| \| pasjpeg/src/jquant1.pas \|
152	149		\| 5264 \| fcl \| image \| \| fcl-image/src/fpreadgif.pas \|
153	150		\| 5232 \| fcl \| jpeg \| \| pasjpeg/src/jdphuff.pas \|
154	151		\| 5152 \| lcl \| base \| \| imagelistcache.pas \|
155	152		\| 5104 \| lcl \| base \| \| widgetset/wsstdctrls.pp \|
156	153		\| 5008 \| fcl \| json \| \| fcl-json/src/jsonscanner.pp \|
157	154		\| 4992 \| lcl \| base \| \| widgetset/wslclclasses.pp \|
158	155		\| 4880 \| fcl \| jpeg \| \| pasjpeg/src/jcphuff.pas \|
159	156		\| 4848 \| fcl \| utils \| \| fcl-base/src/contnrs.pp \|
160	157		\| 4816 \| fcl \| image \| \| fcl-image/src/fptiffcmn.pas \|
161	158		\| 4768 \| rtl \| debug \| \| ../inc/lnfodwrf.pp \|
162	159		\| 4640 \| fcl \| jpeg \| \| pasjpeg/src/jcmaster.pas \|
163	160		\| 4592 \| fcl \| jpeg \| \| pasjpeg/src/jdhuff.pas \|
164	161		\| 4512 \| fcl \| jpeg \| \| pasjpeg/src/jcparam.pas \|
165	162		\| 4256 \| fcl \| jpeg \| \| pasjpeg/src/jcsample.pas \|
166	163		\| 4208 \| lcl \| base \| \| widgetset/wscomctrls.pp \|
167	164		\| 4160 \| fcl \| zlib \| \| paszlib/src/infcodes.pas \|
168	165		\| 3936 \| fcl \| zlib \| \| paszlib/src/inftrees.pas \|
169	166		\| 3616 \| fcl \| jpeg \| \| pasjpeg/src/jcmarker.pas \|
170	167		\| 3584 \| fcl \| zlib \| \| paszlib/src/zstream.pp \|
171	168		\| 3584 \| fcl \| jpeg \| \| pasjpeg/src/jidctint.pas \|
172	169		\| 3488 \| fcl \| image \| \| fcl-image/src/fpwritepnm.pp \|
173	170		\| 3472 \| fcl \| image \| \| fcl-image/src/fpreadpnm.pp \|
174	171		\| 3360 \| fcl \| jpeg \| \| pasjpeg/src/jdmerge.pas \|
175	172		\| 3312 \| lcl \| base \| \| icnstypes.pas \|
176	173		\| 3248 \| fcl \| jpeg \| \| pasjpeg/src/jccoefct.pas \|
177	174		\| 3216 \| fcl \| jpeg \| \| pasjpeg/src/jdsample.pas \|
178	175		\| 3168 \| fcl \| jpeg \| \| pasjpeg/src/jdmainct.pas \|
179	176		\| 3152 \| lcl \| base \| \| widgetset/wsimglist.pp \|
180	177		\| 3120 \| lcl \| base \| \| spin.pp \|
181	178		\| 3120 \| fcl \| jpeg \| \| pasjpeg/src/jdmaster.pas \|
182	179		\| 3104 \| rtl \| winapi \| \| winunits-base/src/uxtheme.pp \|
183	180		\| 2992 \| lcl \| base \| \| widgetset/wscontrols.pp \|
184	181		\| 2944 \| fcl \| json \| \| fcl-json/src/jsonparser.pp \|
185	182		\| 2896 \| fcl \| jpeg \| \| pasjpeg/src/jccolor.pas \|
186	183		\| 2848 \| fcl \| zlib \| \| paszlib/src/zinflate.pas \|
187	184		\| 2832 \| fcl \| jpeg \| \| pasjpeg/src/jdcolor.pas \|
188	185		\| 2816 \| fcl \| jpeg \| \| pasjpeg/src/jcdctmgr.pas \|
189	186		\| 2752 \| lcl \| lazutils \| \| lazmethodlist.pas \|
190	187		\| 2736 \| fcl \| jpeg \| \| pasjpeg/src/jidctred.pas \|
191	188		\| 2704 \| rtl \| debug \| \| ../inc/exeinfo.pp \|
192	189		\| 2688 \| fcl \| jpeg \| \| pasjpeg/src/jidctfst.pas \|
193	190		\| 2576 \| fcl \| jpeg \| \| pasjpeg/src/jidctflt.pas \|
194	191		\| 2496 \| rtl \| rtl \| \| ../objpas/fgl.pp \|
195	192		\| 2464 \| fcl \| jpeg \| \| pasjpeg/src/jdinput.pas \|
196	193		\| 2448 \| lcl \| ws \| \| win32/win32wsfactory.pas \|
197	194		\| 2352 \| fcl \| image \| \| fcl-image/src/fpwritejpeg.pas \|
198	195		\| 2320 \| fcl \| jpeg \| \| pasjpeg/src/jcprepct.pas \|
199	196		\| 2208 \| lcl \| lazutils \| \| lclclasses.pp \|
200	197		\| 2032 \| fcl \| jpeg \| \| pasjpeg/src/jerror.pas \|
201	198		\| 2016 \| rtl \| winapi \| \| winunits-base/src/multimon.pp \|
202	199		\| 2016 \| fcl \| jpeg \| \| pasjpeg/src/jfdctint.pas \|
203	200		\| 1952 \| rtl \| winapi \| \| windows.pp \|
204	201		\| 1888 \| fcl \| jpeg \| \| pasjpeg/src/jdapimin.pas \|
205	202		\| 1872 \| fcl \| image \| \| fcl-image/src/clipping.pp \|
206	203		\| 1824 \| fcl \| zlib \| \| paszlib/src/inffast.pas \|
207	204		\| 1808 \| lcl \| base \| \| extendedstrings.pas \|
208	205		\| 1712 \| lcl \| base \| \| customtimer.pas \|
209	206		\| 1648 \| lcl \| base \| \| helpintfs.pas \|
210	207		\| 1584 \| fcl \| jpeg \| \| pasjpeg/src/jfdctfst.pas \|
211	208		\| 1584 \| fcl \| jpeg \| \| pasjpeg/src/jfdctflt.pas \|
212	209		\| 1584 \| rtl \| rtl \| \| ../objpas/math.pp \|
213	210		\| 1472 \| fcl \| jpeg \| \| pasjpeg/src/jdpostct.pas \|
214	211		\| 1360 \| fcl \| jpeg \| \| pasjpeg/src/jdapistd.pas \|
215	212		\| 1280 \| fcl \| utils \| \| fcl-base/src/custapp.pp \|
216	213		\| 1200 \| lcl \| lazutils \| \| lazfilecache.pas \|
217	214		\| 1152 \| lcl \| base \| \| widgetset/wsmenus.pp \|
218	215		\| 1152 \| lcl \| lazutils \| \| lazclasses.pas \|
219	216		\| 1120 \| fcl \| jpeg \| \| pasjpeg/src/jddctmgr.pas \|
220	217		\| 1056 \| lcl \| base \| \| widgetset/wsforms.pp \|
221	218		\| 1040 \| lcl \| lazutils \| \| integerlist.pas \|
222	219		\| 1024 \| fcl \| jpeg \| \| pasjpeg/src/jcapimin.pas \|
223	220		\| 992 \| lcl \| base \| \| lcltype.pp \|
224	221		\| 848 \| lcl \| lazutils \| \| lazstringutils.pas \|
225	222		\| 832 \| fcl \| image \| \| fcl-image/src/fpimgcanv.pp \|
226	223		\| 768 \| lcl \| base \| \| widgetset/wsproc.pp \|
227	224		\| 688 \| rtl \| rtl \| \| ../objpas/types.pp \|
228	225		\| 672 \| lcl \| ws \| \| win32/win32wsdialogs.pp \|
229	226		\| 672 \| lcl \| lazutils \| \| lazutf8classes.pas \|
230	227		\| 656 \| fcl \| jpeg \| \| pasjpeg/src/jcmainct.pas \|
231	228		\| 656 \| rtl \| rtl \| \| ../inc/fpintres.pp \|
232	229		\| 640 \| lcl \| lazutils \| \| laztracer.pas \|
233	230		\| 624 \| fcl \| jpeg \| \| pasjpeg/src/jdatasrc.pas \|
234	231		\| 560 \| fcl \| image \| \| fcl-image/src/fpimgcmn.pp \|
235	232		\| 528 \| fcl \| zlib \| \| paszlib/src/infutil.pas \|
236	233		\| 528 \| fcl \| utils \| \| fcl-base/src/syncobjs.pp \|
237	234		\| 512 \| lcl \| base \| \| lclmessageglue.pas \|
238	235		\| 496 \| fcl \| jpeg \| \| pasjpeg/src/jutils.pas \|
239	236		\| 496 \| fcl \| jpeg \| \| pasjpeg/src/jdatadst.pas \|
240	237		\| 480 \| fcl \| jpeg \| \| pasjpeg/src/jcapistd.pas \|
241	238		\| 464 \| rtl \| winapi \| \| winunits-base/src/commctrl.pp \|
242	239		\| 432 \| lcl \| base \| \| widgetset/wsextctrls.pp \|
243	240		\| 432 \| fcl \| zlib \| \| paszlib/src/zbase.pas \|
244	241		\| 384 \| fcl \| jpeg \| \| pasjpeg/src/jmemnobs.pas \|
245	242		\| 368 \| fcl \| jpeg \| \| pasjpeg/src/jcomapi.pas \|
246	243		\| 336 \| rtl \| rtl \| \| ../objpas/objpas.pp \|
247	244		\| 288 \| lcl \| base \| \| widgetset/wsdialogs.pp \|
248	245		\| 288 \| fcl \| xml \| \| fcl-xml/src/htmldefs.pp \|
249	246		\| 256 \| fcl \| jpeg \| \| pasjpeg/src/jinclude.pas \|
250	247		\| 256 \| fcl \| jpeg \| \| pasjpeg/src/jcinit.pas \|
251	248		\| 256 \| lcl \| lazutils \| \| lcltaskdialog.pas \|
252	249		\| 256 \| lcl \| lazutils \| \| laz2_xmlread.pas \|
253	250		\| 224 \| lcl \| base \| \| widgetset/wsspin.pp \|
254	251		\| 208 \| lcl \| base \| \| widgetset/wsbuttons.pp \|
255	252		\| 208 \| fcl \| zlib \| \| paszlib/src/adler.pas \|
256	253		\| 192 \| rtl \| rtl \| \| ../objpas/unicodedata.pas \|
257	254		\| 144 \| lcl \| lazutils \| \| avglvltree.pas \|
258	255		\| 128 \| lcl \| base \| \| widgetset/wsreferences.pp \|
259	256		\| 112 \| lcl \| lazutils \| \| stringhashlist.pas \|
260	257		\| 112 \| main \| app \| \| project1.lpr \|
261	258		\| 96 \| rtl \| winapi \| \| ../win/windirs.pp \|
262	259		\| 96 \| rtl \| winapi \| \| ../win/dos.pp \|
263	260		\| 80 \| lcl \| base \| \| lclversion.pas \|
264	261		\| 80 \| lcl \| base \| \| lclplatformdef.pas \|
265	262		\| 80 \| lcl \| base \| \| forms/calcform.pas \|
266	263		\| 80 \| lcl \| lazutils \| \| fileutil.pas \|
267	264		\| 64 \| lcl \| ws \| \| win32/interfaces.pp \|
268	265		\| 64 \| lcl \| lazutils \| \| lazutilities.pas \|
269	266		\| 64 \| lcl \| lazutils \| \| laz2_dom.pas \|
270	267		\| 64 \| rtl \| rtl \| \| ../inc/strings.pp \|
271	268		\| 48 \| lcl \| lazutils \| \| lconvencoding.pas \|
272	269		\| 48 \| lcl \| lazutils \| \| lazsysutils.pas \|
273	270		\| 48 \| lcl \| lazutils \| \| laz2_xmlutils.pas \|
274	271		\| 48 \| lcl \| lazutils \| \| fpcadds.pas \|
275	272		\| 48 \| fcl \| utils \| \| fcl-base/src/rttiutils.pp \|
276	273		\| 32 \| fcl \| utils \| \| fcl-base/src/gettext.pp \|
277	274
278	275		- Note, that zlib is used for PNG images reading and writting
279	276
280	277		### by Lib
281	278
282	279		\| lib \| code \| percentage \|
283	280		\|-------\|---------\|------------\|
284	281		\| rtl \| 340752 \| 15.46% \|
285	282		\| lcl \| 1491184 \| 67.75% \|
286	283		\| fcl \| 372176 \| 16.88% \|
287	284		\| main \| 122 \| 0.01% \|
288	285		\| Total \| 2204234 \| 100% \|
289	286
290	287		## See Also
291	288
292	289		- [[Size Matters]]
293	290
294	291		---
295	292		From the Free Pascal wiki, page "File size and smartlinking", as it stood on 2020-01-24 after a change by Skalogryz, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's [[Licensing]] page. If you have concerns about this material, [message the admin](/wiki-contact).
296	293		Category: FPC
297	294		Category: Lazarus

1

This article is a work in progress about executable size and smartlinking on Lazarus. Feel free to contribute.

2

3

## Introduction

4

5

In Free Pascal, "smartlinking" is removing unused code and variables from the final executable. This is done during the linking stage, when the executable is written using the object files created by the compiler earlier.

6

7

## Case study 1 in Windows

8

9

This study was conducted on the 8th of February 2006 because a Lazarus fully compiled with Smartlinking was Released (version 0.9.12). It intends to establish the relationship between the varying results below with different Lazarus and Free Pascal versions as well as with Smartlinking and without.

10

11

The Variables being studied are:

12

13

- Executable size after strip

14

- Executable size after strip and UPX

15

- Linking time

16

17

Compile time isn´t considered here because it´s too similar on all configurations and much less significant than the link time.

18

19

Executable size without strip isn´t included. Notice that strip was used always from command line with the command:

20

21

strip --strip-all magnifier.exe

22

23

The program being compiled is the Virtual Magnifying Glass. The source and binaries for this program are freely available for download on: <http://magnifier.sourceforge.net>

24

25

About the linking time please note that the utilized computer is 3.2GHz Pentium 4 with Intel motherboard and dual core processor and 512MB of RAM.

26

27

**Results**

28

29

The utilized OS is Windows XP and the 0.9.13 versions are from the same date when 0.9.12 was release. The comparison took place using the following software configurations:

30

31

- Lazarus 0.9.12 available [here](http://sourceforge.net/project/showfiles.php?group_id=89339). Free Pascal 2.0.2 that comes with the installer. LCL and RTL are smartlinked. Refered from now on as simply 0.9.12.

32

33

- Lazarus 0.9.13 downloaded from Subversion from the same date. Free Pascal 2.0.2 installed separately. The LCL is not smartlinked. Refered from now on as simply 0.9.13 + 2.0.2.

34

35

- Lazarus 0.9.13 snapshot. Free Pascal 2.1 that comes with the installer. The LCL is not smartlinked. Refered from now on as simply 0.9.13 + 2.1.

36

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- Lazarus 0.9.13 snapshot. Free Pascal 2.1 that comes with the installer. The LCL is smartlinked. Refered from now on as simply 0.9.13 + 2.1 + SL.

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39

| | 0.9.12 | 0.9.13 + 2.0.2 | 0.9.13 + 2.1 + SL | 0.9.13 + 2.1 |

40

|----|----|----|----|----|

41

| File Size after strip (in bytes) | 1,108,480 | 1,587,712 | 1,425,408 | 1,649,152 |

42

| File Size after UPX (in bytes) | 318,976 | 438,272 | 388,608 | 454,144 |

43

44

49

46

50

47

**Conclusion**

51

48

52

49

The 0.9.13 snapshot from the 8th of February 2006 features a unstable compiler from the 2.1 branch, which can cause the bigger executables and slower linking time as compared to the other versions.

53

50

54

51

The 0.9.12 version has the best file size of all, both with UPX and without, showing that Smartlinking really can diminish the file size in Windows. This, however, does not come without a cost, and the cost is linking time, which is about 3 times higher then without smartlinking.

55

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56

53

The 0.9.12 version already comes fully configured for Smartlinking on Windows and no extra configuration is needed. This was not the case on previous releases.

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58

55

## Remove unused functions in a class

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60

57

Q: If a virtual method of a class is not used at all in the programm will the compiler remove it from the executable ?

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58

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59

A: If you use FPC 2.3.1 with whole-program optimization and the compiler can prove that it is never callable: yes. See [[Whole Program Optimization]] for more information. In case this is in relation to the thread on the Lazarus list about the big executables: note that it has only a limited effect on Lazarus programs, because almost all linked LCL code can potentially be executed (due to the way the LCL is constructed). In fact, I think most savings there come from making a number of virtual method calls non-virtual, rather than from throwing away unreachable code.

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The internal linker can also do it (only throwing away virtual method calls, not turning virtual method calls into static ones), but only on Windows platforms. It is however not currently enabled in the compiler, because the changes break the external linker. It should therefore be turned into a command line option (along with a check that produces an error if you try to link a unit compiled with the option using the external linker), but that hasn't been done yet.

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66

63

Q: How can the compiler determine that a virtual method is unused at all,

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64

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65

A: If you have a class hierarchy TBase-\>TDerived1-\>TDerived2 with a virtual method called "vmethod", and nowhere in the program there is a call to vmethod, then it is unused. Or if it is only called using TDerived2 instances, then if the linker does not find any direct references to TDerived1.vmethod or TBase.vmethod (e.g., via "inherited" calls from TDerived2 methods), it knows that the VMT entries for "vmethod" in TDerived1 and TBase can be set to nil.

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70

67

## Bytes Used

71

68

72

69

Here's a layout by pascal units in bytes used for code. The size is based on Dwarf2 information generated. Doesn't include resources size used by a unit.

73

70

74

71

The project is a single form application (no additional controls used). Lazarus used is a Trunk version of 23 Jan 2020.

75

72

76

73

No optimization was used during compilation.

77

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78

75

79

76

|--------|------|----------|----------|--------------------------------|

80

77

| 238704 | lcl | base | | controls.pp |

81

78

| 144064 | lcl | base | | graphics.pp |

82

79

| 111280 | lcl | ws | | win32/win32int.pp |

83

80

| 106880 | lcl | base | | forms.pp |

84

81

| 98000 | rtl | rtl | | system.pp |

85

82

| 94432 | lcl | base | | intfgraphics.pas |

86

83

| 90352 | lcl | base | | comctrls.pp |

87

84

| 90224 | rtl | rtl | | classes.pp |

88

85

| 59552 | lcl | base | | stdctrls.pp |

89

86

| 51888 | lcl | base | | interfacebase.pp |

90

87

| 50336 | rtl | rtl | | ../win/sysutils.pp |

91

88

| 37728 | lcl | base | | imglist.pp |

92

89

| 35456 | rtl | rtl | | rtl-objpas/src/inc/variants.pp |

93

90

| 33232 | lcl | lazutils | | lazutf8.pas |

94

91

| 31456 | lcl | base | | extctrls.pp |

95

92

| 30912 | fcl | image | | fcl-image/src/fpreadtiff.pas |

96

93

| 30816 | lcl | ws | | win32/win32wscomctrls.pp |

97

94

| 30800 | lcl | ws | | win32/win32wsmenus.pp |

98

95

| 28832 | lcl | base | | menus.pp |

99

96

| 25984 | lcl | base | | maskedit.pp |

100

97

| 24480 | rtl | rtl | | rtl-objpas/src/win/varutils.pp |

101

98

| 24048 | lcl | base | | dialogs.pp |

102

99

| 23632 | fcl | json | | fcl-json/src/fpjson.pp |

103

100

| 23456 | lcl | ws | | win32/win32wsstdctrls.pp |

104

101

| 23408 | lcl | base | | lclintf.pas |

105

102

| 18448 | lcl | base | | lresources.pp |

106

103

| 17904 | lcl | lazutils | | textstrings.pas |

107

104

| 16736 | fcl | image | | fcl-image/src/fpcanvas.pp |

108

105

| 16544 | lcl | lazutils | | graphtype.pp |

109

106

| 13408 | lcl | base | | themes.pas |

110

107

| 13168 | lcl | ws | | win32/win32proc.pp |

111

108

| 13136 | fcl | image | | fcl-image/src/pixtools.pp |

112

109

| 13088 | lcl | lazutils | | lazloggerbase.pas |

113

110

| 12368 | lcl | lazutils | | laz_avl_tree.pp |

114

111

| 11872 | fcl | image | | fcl-image/src/fpimage.pp |

115

112

| 11776 | lcl | base | | actnlist.pas |

116

113

| 11488 | lcl | base | | buttons.pp |

117

114

| 10576 | rtl | debug | | ../inc/heaptrc.pp |

118

115

| 10544 | lcl | ws | | win32/win32wsbuttons.pp |

119

116

| 10464 | rtl | rtl | | ../objpas/typinfo.pp |

120

117

| 9744 | fcl | image | | fcl-image/src/fpreadpng.pp |

121

118

| 9696 | lcl | base | | graphmath.pp |

122

119

| 9536 | lcl | lazutils | | lazlogger.pas |

123

120

| 9424 | lcl | lazutils | | lazfileutils.pas |

124

121

| 9296 | lcl | base | | buttonpanel.pas |

125

122

| 9248 | fcl | image | | fcl-image/src/fpwritetiff.pas |

126

123

| 8864 | lcl | base | | clipbrd.pp |

127

124

| 8768 | lcl | ws | | win32/win32extra.pas |

128

125

| 8768 | fcl | jpeg | | pasjpeg/src/jquant2.pas |

129

126

| 8720 | fcl | jpeg | | pasjpeg/src/jdmarker.pas |

130

127

| 8160 | fcl | image | | fcl-image/src/fpwritepng.pp |

131

128

| 8016 | fcl | image | | fcl-image/src/fpwritebmp.pp |

132

129

| 7792 | fcl | zlib | | paszlib/src/trees.pas |

133

130

| 7648 | fcl | zlib | | paszlib/src/zdeflate.pas |

134

131

| 7536 | fcl | image | | fcl-image/src/ellipses.pp |

135

132

| 7472 | lcl | ws | | win32/win32wsforms.pp |

136

133

| 7456 | fcl | image | | fcl-image/src/fpreadbmp.pp |

137

134

| 7328 | lcl | ws | | win32/win32themes.pas |

138

135

| 6880 | fcl | jpeg | | pasjpeg/src/jdcoefct.pas |

139

136

| 6864 | lcl | base | | lclproc.pas |

140

137

| 6624 | lcl | lazutils | | lazutf16.pas |

141

138

| 6400 | lcl | ws | | win32/win32wscontrols.pp |

142

139

| 6240 | fcl | zlib | | paszlib/src/infblock.pas |

143

140

| 5920 | lcl | base | | lclrescache.pas |

144

141

| 5792 | fcl | image | | fcl-image/src/fpreadjpeg.pas |

145

142

| 5728 | fcl | image | | fcl-image/src/fppixlcanv.pp |

146

143

| 5680 | fcl | ws | | win32/win32wsspin.pp |

147

144

| 5648 | lcl | lazutils | | maps.pp |

148

145

| 5632 | lcl | ws | | win32/win32wsimglist.pp |

149

146

| 5568 | fcl | jpeg | | pasjpeg/src/jchuff.pas |

150

147

| 5520 | fcl | jpeg | | pasjpeg/src/jmemmgr.pas |

151

148

| 5392 | fcl | jpeg | | pasjpeg/src/jquant1.pas |

152

149

| 5264 | fcl | image | | fcl-image/src/fpreadgif.pas |

153

150

| 5232 | fcl | jpeg | | pasjpeg/src/jdphuff.pas |

154

151

| 5152 | lcl | base | | imagelistcache.pas |

155

152

| 5104 | lcl | base | | widgetset/wsstdctrls.pp |

156

153

| 5008 | fcl | json | | fcl-json/src/jsonscanner.pp |

157

154

| 4992 | lcl | base | | widgetset/wslclclasses.pp |

158

155

| 4880 | fcl | jpeg | | pasjpeg/src/jcphuff.pas |

159

156

| 4848 | fcl | utils | | fcl-base/src/contnrs.pp |

160

157

| 4816 | fcl | image | | fcl-image/src/fptiffcmn.pas |

161

158

| 4768 | rtl | debug | | ../inc/lnfodwrf.pp |

162

159

| 4640 | fcl | jpeg | | pasjpeg/src/jcmaster.pas |

163

160

| 4592 | fcl | jpeg | | pasjpeg/src/jdhuff.pas |

164

161

| 4512 | fcl | jpeg | | pasjpeg/src/jcparam.pas |

165

162

| 4256 | fcl | jpeg | | pasjpeg/src/jcsample.pas |

166

163

| 4208 | lcl | base | | widgetset/wscomctrls.pp |

167

164

| 4160 | fcl | zlib | | paszlib/src/infcodes.pas |

168

165

| 3936 | fcl | zlib | | paszlib/src/inftrees.pas |

169

166

| 3616 | fcl | jpeg | | pasjpeg/src/jcmarker.pas |

170

167

| 3584 | fcl | zlib | | paszlib/src/zstream.pp |

171

168

| 3584 | fcl | jpeg | | pasjpeg/src/jidctint.pas |

172

169

| 3488 | fcl | image | | fcl-image/src/fpwritepnm.pp |

173

170

| 3472 | fcl | image | | fcl-image/src/fpreadpnm.pp |

174

171

| 3360 | fcl | jpeg | | pasjpeg/src/jdmerge.pas |

175

172

| 3312 | lcl | base | | icnstypes.pas |

176

173

| 3248 | fcl | jpeg | | pasjpeg/src/jccoefct.pas |

177

174

| 3216 | fcl | jpeg | | pasjpeg/src/jdsample.pas |

178

175

| 3168 | fcl | jpeg | | pasjpeg/src/jdmainct.pas |

179

176

| 3152 | lcl | base | | widgetset/wsimglist.pp |

180

177

| 3120 | lcl | base | | spin.pp |

181

178

| 3120 | fcl | jpeg | | pasjpeg/src/jdmaster.pas |

182

179

| 3104 | rtl | winapi | | winunits-base/src/uxtheme.pp |

183

180

| 2992 | lcl | base | | widgetset/wscontrols.pp |

184

181

| 2944 | fcl | json | | fcl-json/src/jsonparser.pp |

185

182

| 2896 | fcl | jpeg | | pasjpeg/src/jccolor.pas |

186

183

| 2848 | fcl | zlib | | paszlib/src/zinflate.pas |

187

184

| 2832 | fcl | jpeg | | pasjpeg/src/jdcolor.pas |

188

185

| 2816 | fcl | jpeg | | pasjpeg/src/jcdctmgr.pas |

189

186

| 2752 | lcl | lazutils | | lazmethodlist.pas |

190

187

| 2736 | fcl | jpeg | | pasjpeg/src/jidctred.pas |

191

188

| 2704 | rtl | debug | | ../inc/exeinfo.pp |

192

189

| 2688 | fcl | jpeg | | pasjpeg/src/jidctfst.pas |

193

190

| 2576 | fcl | jpeg | | pasjpeg/src/jidctflt.pas |

194

191

| 2496 | rtl | rtl | | ../objpas/fgl.pp |

195

192

| 2464 | fcl | jpeg | | pasjpeg/src/jdinput.pas |

196

193

| 2448 | lcl | ws | | win32/win32wsfactory.pas |

197

194

| 2352 | fcl | image | | fcl-image/src/fpwritejpeg.pas |

198

195

| 2320 | fcl | jpeg | | pasjpeg/src/jcprepct.pas |

199

196

| 2208 | lcl | lazutils | | lclclasses.pp |

200

197

| 2032 | fcl | jpeg | | pasjpeg/src/jerror.pas |

201

198

| 2016 | rtl | winapi | | winunits-base/src/multimon.pp |

202

199

| 2016 | fcl | jpeg | | pasjpeg/src/jfdctint.pas |

203

200

| 1952 | rtl | winapi | | windows.pp |

204

201

| 1888 | fcl | jpeg | | pasjpeg/src/jdapimin.pas |

205

202

| 1872 | fcl | image | | fcl-image/src/clipping.pp |

206

203

| 1824 | fcl | zlib | | paszlib/src/inffast.pas |

207

204

| 1808 | lcl | base | | extendedstrings.pas |

208

205

| 1712 | lcl | base | | customtimer.pas |

209

206

| 1648 | lcl | base | | helpintfs.pas |

210

207

| 1584 | fcl | jpeg | | pasjpeg/src/jfdctfst.pas |

211

208

| 1584 | fcl | jpeg | | pasjpeg/src/jfdctflt.pas |

212

209

| 1584 | rtl | rtl | | ../objpas/math.pp |

213

210

| 1472 | fcl | jpeg | | pasjpeg/src/jdpostct.pas |

214

211

| 1360 | fcl | jpeg | | pasjpeg/src/jdapistd.pas |

215

212

| 1280 | fcl | utils | | fcl-base/src/custapp.pp |

216

213

| 1200 | lcl | lazutils | | lazfilecache.pas |

217

214

| 1152 | lcl | base | | widgetset/wsmenus.pp |

218

215

| 1152 | lcl | lazutils | | lazclasses.pas |

219

216

| 1120 | fcl | jpeg | | pasjpeg/src/jddctmgr.pas |

220

217

| 1056 | lcl | base | | widgetset/wsforms.pp |

221

218

| 1040 | lcl | lazutils | | integerlist.pas |

222

219

| 1024 | fcl | jpeg | | pasjpeg/src/jcapimin.pas |

223

220

| 992 | lcl | base | | lcltype.pp |

224

221

| 848 | lcl | lazutils | | lazstringutils.pas |

225

222

| 832 | fcl | image | | fcl-image/src/fpimgcanv.pp |

226

223

| 768 | lcl | base | | widgetset/wsproc.pp |

227

224

| 688 | rtl | rtl | | ../objpas/types.pp |

228

225

| 672 | lcl | ws | | win32/win32wsdialogs.pp |

229

226

| 672 | lcl | lazutils | | lazutf8classes.pas |

230

227

| 656 | fcl | jpeg | | pasjpeg/src/jcmainct.pas |

231

228

| 656 | rtl | rtl | | ../inc/fpintres.pp |

232

229

| 640 | lcl | lazutils | | laztracer.pas |

233

230

| 624 | fcl | jpeg | | pasjpeg/src/jdatasrc.pas |

234

231

| 560 | fcl | image | | fcl-image/src/fpimgcmn.pp |

235

232

| 528 | fcl | zlib | | paszlib/src/infutil.pas |

236

233

| 528 | fcl | utils | | fcl-base/src/syncobjs.pp |

237

234

| 512 | lcl | base | | lclmessageglue.pas |

238

235

| 496 | fcl | jpeg | | pasjpeg/src/jutils.pas |

239

236

| 496 | fcl | jpeg | | pasjpeg/src/jdatadst.pas |

240

237

| 480 | fcl | jpeg | | pasjpeg/src/jcapistd.pas |

241

238

| 464 | rtl | winapi | | winunits-base/src/commctrl.pp |

242

239

| 432 | lcl | base | | widgetset/wsextctrls.pp |

243

240

| 432 | fcl | zlib | | paszlib/src/zbase.pas |

244

241

| 384 | fcl | jpeg | | pasjpeg/src/jmemnobs.pas |

245

242

| 368 | fcl | jpeg | | pasjpeg/src/jcomapi.pas |

246

243

| 336 | rtl | rtl | | ../objpas/objpas.pp |

247

244

| 288 | lcl | base | | widgetset/wsdialogs.pp |

248

245

| 288 | fcl | xml | | fcl-xml/src/htmldefs.pp |

249

246

| 256 | fcl | jpeg | | pasjpeg/src/jinclude.pas |

250

247

| 256 | fcl | jpeg | | pasjpeg/src/jcinit.pas |

251

248

| 256 | lcl | lazutils | | lcltaskdialog.pas |

252

249

| 256 | lcl | lazutils | | laz2_xmlread.pas |

253

250

| 224 | lcl | base | | widgetset/wsspin.pp |

254

251

| 208 | lcl | base | | widgetset/wsbuttons.pp |

255

252

| 208 | fcl | zlib | | paszlib/src/adler.pas |

256

253

| 192 | rtl | rtl | | ../objpas/unicodedata.pas |

257

254

| 144 | lcl | lazutils | | avglvltree.pas |

258

255

| 128 | lcl | base | | widgetset/wsreferences.pp |

259

256

| 112 | lcl | lazutils | | stringhashlist.pas |

260

257

| 112 | main | app | | project1.lpr |

261

258

| 96 | rtl | winapi | | ../win/windirs.pp |

262

259

| 96 | rtl | winapi | | ../win/dos.pp |

263

260

| 80 | lcl | base | | lclversion.pas |

264

261

| 80 | lcl | base | | lclplatformdef.pas |

265

262

| 80 | lcl | base | | forms/calcform.pas |

266

263

| 80 | lcl | lazutils | | fileutil.pas |

267

264

| 64 | lcl | ws | | win32/interfaces.pp |

268

265

| 64 | lcl | lazutils | | lazutilities.pas |

269

266

| 64 | lcl | lazutils | | laz2_dom.pas |

270

267

| 64 | rtl | rtl | | ../inc/strings.pp |

271

268

| 48 | lcl | lazutils | | lconvencoding.pas |

272

269

| 48 | lcl | lazutils | | lazsysutils.pas |

273

270

| 48 | lcl | lazutils | | laz2_xmlutils.pas |

274

271

| 48 | lcl | lazutils | | fpcadds.pas |

275

272

| 48 | fcl | utils | | fcl-base/src/rttiutils.pp |

276

273

| 32 | fcl | utils | | fcl-base/src/gettext.pp |

277

274

278

275

- Note, that zlib is used for PNG images reading and writting

279

276

280

277

### by Lib

281

278

282

279

| lib | code | percentage |

283

280

|-------|---------|------------|

284

281

| rtl | 340752 | 15.46% |

285

282

| lcl | 1491184 | 67.75% |

286

283

| fcl | 372176 | 16.88% |

287

284

| main | 122 | 0.01% |

288

285

| Total | 2204234 | 100% |

289

286

290

287

## See Also

291

288

292

289

- [[Size Matters]]

293

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294

291

---

295

292

*From the Free Pascal wiki, page "File size and smartlinking", as it stood on 2020-01-24 after a change by Skalogryz, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's [[Licensing]] page. If you have concerns about this material, [message the admin](/wiki-contact).*

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Category: FPC

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Category: Lazarus