[LLVMdev] How to explain this weird phenomenon????????

Alexander Potapenko
Tue, 10 Apr 2012 13:02:02 -0000

Your files do not appear to implement the check() function.

On Tue, Apr 10, 2012 at 4:57 PM, 15102925731 <zhenkaixd at 126.com>
wrote:
> Hi, my friends
>
> I finally insert the callInst into the hello.bc file.Then I compile the
> hello.bc to hello.o file and the check.c to check.o file. And I think by
> link those to .o file togetherI can get the executable ELF file(clang
> hello.o check.o -o finalfile).
>
> But when I link the two objective file, it said
>  "hello.o: In function `main':
> hello.bc:(.text+0x69): undefined reference to `check'
> clang: error: linker command failed with exit code 1 (use -v to see
> invocation)" What's wrong??
>
>  To make it readable I convert the .bc file into .ll file using llvm-dis.
> The IR code is as follow, any help?
>
> Before running the pass
> ; ModuleID = 'hello.bc'
> target datalayout >
"e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32-n8:16:32-S128"
> target triple = "i386-pc-linux-gnu"
>
> @.str = private unnamed_addr constant [18 x i8] c"add result is
%d\0A\00",
> align 1
> @.str1 = private unnamed_addr constant [20 x i8] c"minus result is
> %d\0A\00", align 1
> @str = private unnamed_addr constant [13 x i8] c"hello world!\00"
>
> define i32 @add(i32 %a, i32 %b) nounwind readnone {
> entry:
>   %add = add nsw i32 %b, %a
>   ret i32 %add
> }
>
> define i32 @minus(i32 %a, i32 %b) nounwind readnone {
> entry:
>   %sub = sub nsw i32 %a, %b
>   ret i32 %sub
> }
>
> define i32 @main() nounwind {
> entry:
>   %call1 = tail call i32 (i8*, ...)* @printf(i8* getelementptr inbounds
([18
> x i8]* @.str, i32 0, i32 0), i32 3) nounwind
>   %call3 = tail call i32 (i8*, ...)* @printf(i8* getelementptr inbounds
([20
> x i8]* @.str1, i32 0, i32 0), i32 1) nounwind
>   %puts = tail call i32 @puts(i8* getelementptr inbounds ([13 x i8]* @str,
> i32 0, i32 0))
>   ret i32 0
> }
>
> declare i32 @printf(i8* nocapture, ...) nounwind
>
> declare i32 @puts(i8* nocapture) nounwind
> After running the pass
> ; ModuleID = 'newhello.bc'
> target datalayout >
"e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32-n8:16:32-S128"
> target triple = "i386-pc-linux-gnu"
>
> @.str = private unnamed_addr constant [18 x i8] c"add result is
%d\0A\00",
> align 1
> @.str1 = private unnamed_addr constant [20 x i8] c"minus result is
> %d\0A\00", align 1
> @str = private unnamed_addr constant [13 x i8] c"hello world!\00"
>
> define i32 @add(i32 %a, i32 %b) nounwind readnone {
> entry:
>   %add = add nsw i32 %b, %a
>   ret i32 %add
> }
>
> define i32 @minus(i32 %a, i32 %b) nounwind readnone {
> entry:
>   %sub = sub nsw i32 %a, %b
>   ret i32 %sub
> }
>
> define i32 @main() nounwind {
> entry:
>   %call1 = tail call i32 (i8*, ...)* @printf(i8* getelementptr inbounds
([18
> x i8]* @.str, i32 0, i32 0), i32 3) nounwind
>   %call3 = tail call i32 (i8*, ...)* @printf(i8* getelementptr inbounds
([20
> x i8]* @.str1, i32 0, i32 0), i32 1) nounwind
>   %CallCheck = call i32 @check()
>   %puts = tail call i32 @puts(i8* getelementptr inbounds ([13 x i8]* @str,
> i32 0, i32 0))
>   ret i32 0
> }
>
> declare i32 @printf(i8* nocapture, ...) nounwind
>
> declare i32 @puts(i8* nocapture) nounwind
>
> declare i32 @check()
> The original hello.c file
> #include <stdio.h>
> extern int check();
> int add(int a,int b)
> {
>     return a+b;
> }
>
> int minus(int a,int b)
> {
>     return a-b;
> }
> int main()
> {
>     int a=2,b=1;
>     printf("add result is %d\n",add(a,b));
>     printf("minus result is %d\n",minus(a,b));
>     printf("hello world!\n");
>     return 0;
> }
> The original check.c file
> #include <stdio.h>
> void print()
> {
>     printf("Check function works!\n");
>
> }
> --
>             祝好！
>
>   甄凯
>
------------------------------------------------------------------------------------------------------
> 2012-04-10
>
------------------------------------------------------------------------------------------------------
> Name: 甄凯(ZhenKai)
> Homepage:http://www.renren.com/262729393
> Email: zhenkaixd at 126.com or 846227103 at qq.com
> TEL: 15810729006(Beijing)
> Address: Room I-406, Central Building, Tsinghua University, Beijing, China.
> 100084.
>
> At 2012-04-10 20:00:08,15102925731 <zhenkaixd at 126.com> wrote:
>
> I did it !!!!
> YOU MADE MY DAY  !!!!!!!!!!!!!!!
>
> --
>             祝好！
>
>   甄凯
>
------------------------------------------------------------------------------------------------------
> 2012-04-10
>
------------------------------------------------------------------------------------------------------
> Name: 甄凯(ZhenKai)
> Homepage:http://www.renren.com/262729393
> Email: zhenkaixd at 126.com or 846227103 at qq.com
> TEL: 15810729006(Beijing)
> Address: Room I-406, Central Building, Tsinghua University, Beijing, China.
> 100084.
>
>
> At 2012-04-10 19:55:04,"Duncan Sands" <baldrick at
free.fr> wrote:
>>Hi,
>>
>>> BTW the opt command I use is *"opt -load ../../../Debug+Asserts/lib/Hello.so
>>> -hello <hello.bc> -o hello.bc"*
>>
>>just use hello.bc not <hello.bc> otherwise the shell will redirect input and
>>output.
>>
>>Ciao, Duncan.
>>_______________________________________________
>>LLVM Developers mailing list
>>LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>>http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
>
>
>
>
>
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>



--
Alexander Potapenko
Software Engineer
Google Moscow