How to set breakpoints before mainCRTStartup?

[Dalibor Topic]

Dalibor Topic wrote:
> Hi all,
> 
> in my attempts to fix an ugly bug in kaffe on Cygwin, the bug I'm trying 
> to squish turned out to be triggered by something that happens *before* 
> main is called.
> 
> The opcode at the start of the function in question is apparently 
> modified before the program actually calls main. So when I break on main 
> in gdb, and print the value of the first opcode of the function before I 
> run the program, and after it breaks at main, the first opcode of the 
> function in question is different, which leads to a crash as soon as the 
> function is called.
> 
> Since I'd like to know what modifes that opcode, I hope to be able to 
> set a breakpoint in gdb on the code that is executed before main in Cygwin.
> 
> Any idea how to do that, i.e. where to put the breakpoint? Are there 
> some docs on what happends before main() on cygwin that I could look up 
> for reference while trying to hunt down this bug?

It turns out that the bug happens even before mainCRTStartup.

Has anyone seen something like that before?


cheers,
dalibor topic


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