[llvm-dev] LLVM IR source line error

[Muhui Jiang via llvm-dev]

Hi David

Thank you very much for your suggestions. ScopeLine works well. It could
represent the start of a function. Do you know whether I can get the start
column of this function?  Many Thanks

Regards
Muhui

2018-05-30 3:25 GMT+08:00 David Blaikie <dblaikie at gmail.com>:

>
>
> On Tue, May 29, 2018 at 5:25 AM Muhui Jiang via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>> Hi
>>
>> I am using LLVM to help me do some code analysis. I wrote a LLVM Function
>> Pass to help me to generate some information. I use the code below to get
>> the source line information for every instruction.
>>
>> for (BasicBlock &BB : F){
>>     for(Instruction &I: BB){
>>     DILocation* Loc =  I.getDebugLoc().get();
>>     unsigned Line = Loc->getLine()
>>     }
>> }
>>
>> I think the function's first block's first instruction's source line
>> should be the beginning of the function.
>>
>
> I'm not sure why that would necessarily be true - if there are no
> instructions associated with the beginning of the function. (no frame
> setup, no allocas, etc)
>
>
>> Most of the functions inside the binary follow the rules. However, I
>> found the file system.h in the coreutils-8.28 has a function like below:
>>
>> 611 static inline void
>> 612 emit_backup_suffix_note (void)
>> 613 {
>> 614   fputs (_("\
>> 615 \n\
>>
>> 616 The backup suffix is '~', unless set with --suffix or
>> SIMPLE_BACKUP_SUFFIX.\n\
>> 617 The version control method may be selected via the --backup option or
>> through\n\
>> 618 the VERSION_CONTROL environment variable.  Here are the values:\n\
>> 619 \n\
>> 620 "), stdout);
>> 621   fputs (_("\
>> 622   none, off       never make backups (even if --backup is given)\n\
>> 623   numbered, t     make numbered backups\n\
>> 624   existing, nil   numbered if numbered backups exist, simple
>> otherwise\n\
>> 625   simple, never   always make simple backups\n\
>> 626 "), stdout);
>> 627 }
>>
>> When analysis this function. The first block's first instruction's source
>> line is 614 rather than 612 or 613.
>>
>
> The first instruction is the call to gettext (presumably expressed by the
> _ macro) that is on line 614. Doesn't look like there's any instruction
> that could/should be attributed to 612 or 613.
>
> The DISubprogram describing the function should probably have some a
> "scopeLine" attribute of 613, which might be what you want.
>
>
>> Is it a bug or any other meaning resulting in such case. Below is the IR.
>> The first IR's source line if 614.
>>
>>   %call = call i8* @gettext(i8* getelementptr inbounds ([221 x i8], [221
>> x i8]* @.str.42, i32 0    , i32 0)) #12, !dbg !1295
>>   %0 = load %struct._IO_FILE*, %struct._IO_FILE** @stdout, align 4, !dbg
>> !1295
>>   %call1 = call i32 @fputs_unlocked(i8* %call, %struct._IO_FILE* %0),
>> !dbg !1295
>>   %call2 = call i8* @gettext(i8* getelementptr inbounds ([222 x i8], [222
>> x i8]* @.str.43, i32     0, i32 0)) #12, !dbg !1296
>>   %1 = load %struct._IO_FILE*, %struct._IO_FILE** @stdout, align 4, !dbg
>> !1296
>>   %call3 = call i32 @fputs_unlocked(i8* %call2, %struct._IO_FILE* %1),
>> !dbg !1296
>>   ret void, !dbg !1297
>>
>> Can anyone help me or give me some suggestions? Many Thanks
>>
>> Regards
>> Muhui
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20180530/18de0322/attachment.html>