size of executables
Sivo Schilling
sivo.schilling at web.de
Mon Aug 11 02:28:16 PDT 2008
Hi all,
below are two versions of a small test code nailed down from a more complex
project.
In case 1 there are some static arrays inside a struct which is declared at
function scope. Then an instance of this struct is used in the same scope.
Case 2 differs from case 1 only in that the static arrays are placed direct
into the function, but with equal size and layout as before.
--- test_mdsasf.d ---
/***
* test of multi dimensional static arrays
*
* Case 1: - static arrays inside a struct
* - struct declaration at function scope
*/
module test_mdsasf;
import std.stdio;
void fnMDSA()
{
enum
{
SD = 33 // single dimension
}
struct MDSA
{
float[SD][SD][SD] m2;
int[SD][SD][SD] wt;
int[SD][SD][SD] mr;
int[SD][SD][SD] mg;
int[SD][SD][SD] mb;
}
MDSA mdsa;
void initMDSA()
{
// Clear all
(cast(ubyte*)&mdsa)[0..mdsa.sizeof] = 0;
}
void testMDSA()
{
writefln("before init: mdsa.m2[%d][%d][%d] = %f", 13, 4, 11, mdsa.m2[13][4][11]);
// initialize
initMDSA();
// show result
writefln("after init: mdsa.m2[%d][%d][%d] = %f", 13, 4, 11, mdsa.m2[13][4][11]);
// assign a value
mdsa.m2[13][4][11] = 13*4*11;
// show result
writefln("after assign: mdsa.m2[%d][%d][%d] = %f", 13, 4, 11, mdsa.m2[13][4][11]);
}
testMDSA();
}
void main()
{
fnMDSA();
}
--- test_mdsaf.d ---
/***
* test of multi dimensional static arrays
*
* Case 2: - static arrays inside a function
*/
module test_mdsaf;
import std.stdio;
void fnMDSA()
{
enum
{
SD = 33 // single dimension
}
float[SD][SD][SD] m2;
int[SD][SD][SD] wt;
int[SD][SD][SD] mr;
int[SD][SD][SD] mg;
int[SD][SD][SD] mb;
void initMDSA()
{
// Clear all
(cast(ubyte*)&m2)[0..m2.sizeof] = 0;
(cast(ubyte*)&wt)[0..wt.sizeof] = 0;
(cast(ubyte*)&wt)[0..mr.sizeof] = 0;
(cast(ubyte*)&wt)[0..mg.sizeof] = 0;
(cast(ubyte*)&wt)[0..mb.sizeof] = 0;
}
void testMDSA()
{
writefln("before init: m2[%d][%d][%d] = %f", 13, 4, 11, m2[13][4][11]);
// initialize
initMDSA();
// show result
writefln("after init: m2[%d][%d][%d] = %f", 13, 4, 11, m2[13][4][11]);
// assign a value
m2[13][4][11] = 13*4*11;
// show result
writefln("after assign: m2[%d][%d][%d] = %f", 13, 4, 11, m2[13][4][11]);
}
testMDSA();
}
void main()
{
fnMDSA();
}
--- end of files ---
But comparing the size of the two executables is very weird:
case 1: 929.820 bytes (test_mdsasf_v2.exe)
case 2: 216.604 bytes (test_mdsaf_v2.exe)
both compiled with DMD 2.018 (switches: -release -O -inline) on WinXP SP3.
Comparing the corresponding map files it becomes clear that this considerable size
difference comes from the _DATA section (see <---):
case 1 | case 2:
---------------------------------------------------+--------------------------------------------------
Start Length Name Class | Start Length Name Class
0002:00000000 0002B40BH _TEXT CODE 32-bit | 0002:00000000 0002CA8BH _TEXT CODE 32-bit
0002:0002B40C 00000150H ICODE ICODE 32-bit | 0002:0002CA8C 00000150H ICODE ICODE 32-bit
0003:00000000 00000004H .tls tls 32-bit | 0003:00000000 00000004H .tls tls 32-bit
0003:00000004 00000004H .tls$ tls 32-bit | 0003:00000004 00000004H .tls$ tls 32-bit
0003:00000008 00000004H .tls$ZZZ tls 32-bit | 0003:00000008 00000004H .tls$ZZZ tls 32-bit
0004:00000000 00000004H .CRT$XIA DATA 32-bit | 0004:00000000 00000004H .CRT$XIA DATA 32-bit
0004:00000010 00000004H .CRT$XIZ DATA 32-bit | 0004:00000010 00000004H .CRT$XIZ DATA 32-bit
0004:00000020 00000004H .CRT$XCA DATA 32-bit | 0004:00000020 00000004H .CRT$XCA DATA 32-bit
0004:00000030 00000004H .CRT$XCZ DATA 32-bit | 0004:00000030 00000004H .CRT$XCZ DATA 32-bit
0004:00000040 00000004H .CRT$XPA DATA 32-bit | 0004:00000040 00000004H .CRT$XPA DATA 32-bit
0004:00000050 00000004H .CRT$XPZ DATA 32-bit | 0004:00000050 00000004H .CRT$XPZ DATA 32-bit
0004:00000060 00000004H .CRT$XTA DATA 32-bit | 0004:00000060 00000004H .CRT$XTA DATA 32-bit
0004:00000070 00000004H .CRT$XTZ DATA 32-bit | 0004:00000070 00000004H .CRT$XTZ DATA 32-bit
0004:00000074 00000000H IMP__DATA IMP__DATA 32-bit| 0004:00000074 00000000H IMP__DATA IMP__DATA 32-bit
0004:00000080 000B5168H _DATA DATA 32-bit | 0004:00000080 000059A8H _DATA DATA 32-bit <---
0004:000B51E8 00000000H FMB DATA 32-bit | 0004:00005A28 00000000H FMB DATA 32-bit
0004:000B51E8 0000003CH FM DATA 32-bit | 0004:00005A28 0000003CH FM DATA 32-bit
0004:000B5224 00000000H FME DATA 32-bit | 0004:00005A64 00000000H FME DATA 32-bit
0004:000B5224 00000000H XIB DATA 32-bit | 0004:00005A64 00000000H XIB DATA 32-bit
0004:000B5224 00000018H XI DATA 32-bit | 0004:00005A64 00000018H XI DATA 32-bit
0004:000B523C 00000000H XIE DATA 32-bit | 0004:00005A7C 00000000H XIE DATA 32-bit
0004:000B523C 00000000H XIFCB DATA 32-bit | 0004:00005A7C 00000000H XIFCB DATA 32-bit
0004:000B523C 00000004H XIFU DATA 32-bit | 0004:00005A7C 00000004H XIFU DATA 32-bit
0004:000B5240 00000000H XIFL DATA 32-bit | 0004:00005A80 00000000H XIFL DATA 32-bit
0004:000B5240 00000004H XIFM DATA 32-bit | 0004:00005A80 00000004H XIFM DATA 32-bit
0004:000B5244 00000000H XIFCE DATA 32-bit | 0004:00005A84 00000000H XIFCE DATA 32-bit
0004:000B5244 00000000H XCB DATA 32-bit | 0004:00005A84 00000000H XCB DATA 32-bit
0004:000B5244 0000000CH XC DATA 32-bit | 0004:00005A84 0000000CH XC DATA 32-bit
0004:000B5250 00000000H XCE DATA 32-bit | 0004:00005A90 00000000H XCE DATA 32-bit
0004:000B5250 00000000H CONST CONST 32-bit | 0004:00005A90 00000000H CONST CONST 32-bit
0004:000B5250 00000000H EEND ENDBSS 32-bit | 0004:00005A90 00000000H EEND ENDBSS 32-bit
0004:000B5250 000025BCH _BSS BSS 32-bit | 0004:00005A90 000025BCH _BSS BSS 32-bit
0004:000B780C 00000000H XOB BSS 32-bit | 0004:0000804C 00000000H XOB BSS 32-bit
0004:000B780C 00000004H XO BSS 32-bit | 0004:0000804C 00000004H XO BSS 32-bit
0004:000B7810 00000000H XOE BSS 32-bit | 0004:00008050 00000000H XOE BSS 32-bit
0004:000B7810 00000000H XOFB BSS 32-bit | 0004:00008050 00000000H XOFB BSS 32-bit
0004:000B7810 00000108H XOF BSS 32-bit | 0004:00008050 00000108H XOF BSS 32-bit
0004:000B7918 00000000H XOFE BSS 32-bit | 0004:00008158 00000000H XOFE BSS 32-bit
0004:000B7920 00000419H c_common BSS 32-bit | 0004:00008160 00000419H c_common BSS 32-bit
0004:000B7D40 00000000H STACK STACK 32-bit | 0004:00008580 00000000H STACK STACK 32-bit
|
Program entry point at 00023BDC | Program entry point at 0002525C
The difference in size of the _DATA section of the two cases above is
case 1 case 2 delta
000B5168H - 000059A8H = 000AF7C0H --> 718.784 byte!
To this end i've no idea what in case 1 goes into the _DATA section, but i suppose it's an (hidden ?)
instance of struct MDSA (MDSA.sizeof = 718.740 bytes) at global scope.
What do you think ?
Regards.
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