Question about %jmp_buf size in the setjmp/longjmp example code

[JOE1994]

Hello ,
first of all, thank you for sharing and maintaining this gitbook! 😄 😸

I noticed that in the setjmp/longjmp example code, jmp_buf is set and used as a single i32 variable.

%jmp_buf = type { i32 }
declare i32 @setjmp(%jmp_buf* %env)
declare void @longjmp(%jmp_buf* %env, i32 %val)

define i32 @main(i32 %argc, i8** %argv) nounwind {
	; "try" keyword expands to a call to @setjmp
	%env = alloca %jmp_buf
	%status = call i32 @setjmp(%jmp_buf* %env)
	%1 = icmp eq i32 %status, 0
	br i1 %1, label %.body, label %.catch_block

The LLVM docs on setjmp mentions that the single parameter to the setjmp intrinsic (i32 @llvm.eh.sjlj.setjmp(i8* %setjmp_buf)) is a pointer to a five word buffer in which the calling context is saved.
Following the documentation, shouldn't the size of jmp_buf be set to an array [5 x i32] ?
(assuming a 32-bit system)

Thank you for reading!

[archfrog]

I think you're right :)

It has been some years since I wrote that example and obviously it never ran. Or, if it ran, it must have been sheer luck :-) I don't know what went through my head, perhaps I just put in i32 with the intent of fixing it later and then forgot about it.

If you want to, you can submit a pull request with the fixed code.

[JOE1994]

I'll try to submit a PR soon !

[archfrog]

Thank you!