[LLVMdev] trouble with getelementptr

[Dale Johannesen]

On Jan 5, 2008, at 4:09 PM, Zalunin Pavel wrote:

> Hello,
>   I have next code:
>  ;begin
> ; ModuleID = 'sample.lz'
> @.str1 = internal constant [20 x i8] c"\22hello, cruel world 
> \22"                ; <[20 x i8]*> [#uses=1]
> @.str4 = internal constant [9 x i8] c"\22hello, \22"            ; < 
> [9 x i8]*> [#uses=1]
> @.str7 = internal constant [7 x i8] c"\22heya!\22"              ; < 
> [7 x i8]*> [#uses=1]
>
> declare i32 @puts(i8*)

puts expects strings to be null-terminated.  Compare output of llvm- 
gcc -emit-llvm -S -O0.

> declare i8 @strcat(i8*, i8*)
>
> define i32 @main() {
> mainBlock:
>         %tmp2 = getelementptr [20 x i8]* @.str1, i64 0, i64  
> 0           ; <i8*> [#uses=1]
>         %tmp3 = call i32 @puts( i8* %tmp2 )             ; <i32>  
> [#uses=0]
>         %tmp5 = getelementptr [9 x i8]* @.str4, i64 0, i64  
> 0            ; <i8*> [#uses=1]
>         %tmp6 = call i32 @puts( i8* %tmp5 )             ; <i32>  
> [#uses=0]
>         %tmp8 = getelementptr [7 x i8]* @.str7, i64 0, i64  
> 0            ; <i8*> [#uses=1]
>         %tmp9 = call i32 @puts( i8* %tmp8 )             ; <i32>  
> [#uses=0]
>         ret i32 0
> }
>
>  ;end
>
> llvm-as test.ll -o test.ll.bc
> llc test.ll.bc -o test.ll.s
> gcc test.ll.s -o test.ll.native
>
> After running a see next:
>
> whiter4bbit at LiZa /home/whiter4bbit/programming
> /study/yapis/liza $ ./test.ll.native
> "hello, cruel world""hello, ""heya!"
> "hello, ""heya!"
> "heya!"
>
> It isn't a target result:) target is:
>
> whiter4bbit at LiZa /home/whiter4bbit/programming/study/yapis/liza $ ./ 
> test.ll.native
> "hello, cruel world"
> "hello, "
> "heya!"
>
> what is the trouble here?
> I think about freeing memory after using getelementptr, is it right? 
> (and if it right can anybody answer 'how?')
> Help me please...
>
> Best regards, Zalunin Pavel
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