[llvm-dev] LLVM IR source line error

[David Blaikie via llvm-dev]

I don't believe so, no. The ScopeLine was added for adjusting profile
samples & was just what was needed for that task - I don't think there's
any equivalent column info.

On Tue, May 29, 2018 at 11:54 PM Muhui Jiang <jiangmuhui at gmail.com> wrote:

> 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
>>>
>>
>
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