[llvm-dev] LLVM IR source line error

[Muhui Jiang via llvm-dev]

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. 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. 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
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