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Stack usage on recursive call |
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znakeeye 
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Joined: 26 July 2006 Status: Offline Points: 1672 |
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 Topic: Stack usage on recursive callPosted: 29 November 2009 at 5:08pm |
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VS 2008 SP1.
Consider this function: void foo(int x)
{
foo(x + 1);
}
If I add a parameter "int y", I would expect the stack usage to increase by 4 bytes. However, in my case (in debug mode) it increases with 72 bytes.
Can somebody please explain this? 68 extra bytes is a LOT! :(
Sample program: uploads/20091203_064021_StackBomb.zip
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mgampi
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Posted: 30 November 2009 at 4:44am |
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Additional stack checking code???
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Martin
Product: Xtreme Toolkit v 19.0.0, new Projects v 19.1.0 Platform: Windows 10 v 1909 (64bit) Language: VC++ 2017 |
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znakeeye
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Posted: 01 December 2009 at 6:19am |
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Sure, but 68 bytes?! It makes it hard to debug my recursive function, since it blows the stack. 6 parameters yields 432 bytes, lol...
In Release-mode the recursive call is optimized away completely, so there is no need in rewriting my algorithm.
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znakeeye
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Posted: 03 December 2009 at 6:41am |
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Please see attached sample. It demonstrates this.
It's totally sick! :(
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jimmy
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Posted: 03 December 2009 at 8:10am |
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Hi,
Every parameter need 4 Byte. CALL need 4 Byte. Save EBP need 4 Byte. Save some other register need 3*4 Byte. "Full runtime check" need 160 Byte. You can disable it. if i have only 1 parameter it need 108 Byte. i calculate 4 Byte parameter 4 Byte call 4 Byte save ebp 4 byte save this pointer 8 byte for local variables --------- 24 Byte 108 - 24 = 84 Byte too much ??? ================== i don't know more. Jimmy |
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znakeeye
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Posted: 03 December 2009 at 9:09am |
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I think I'll disable runtime check in this particular cpp file. In optimized release-mode the stack usage is 0 bytes (!). Do you know a #pragma to disable runtime check? |
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jimmy
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Posted: 03 December 2009 at 10:17am |
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Hi,
Start Visual Studio, press F1 search #pragma , see runtime_checks and click it. Than you see this #pragma runtime_checks( "", off ) Jimmy |
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jimmy
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Posted: 03 December 2009 at 10:23am |
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See also
#pragma check_stack([ {on | off}] ) #pragma check_stack{+ | –} Jimmy |
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znakeeye
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Posted: 04 December 2009 at 5:35am |
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Thanks, but these have no effect in debug-mode, as it seems :/
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