[LLVMdev] line number information

Chris Lattner sabre at nondot.org
Sat Apr 8 10:30:50 PDT 2006

On Sat, 8 Apr 2006, Jim Laskey wrote:
> If you look at the stoppoint calls you'll see that you can find the line 
> number and if you follow the compile unit argument on the call you will find 
> the file.  The byte codes that follow the call would have been generated by 
> the code on that source line.

I'd suggest an approach like this:

Given an instruction in the a basic block, scan up and/or down the basic 
block, stopping at the first llvm.dbg.stoppoint instruction.  Something 
like this should work:

#include "llvm/IntrinsicInst.h"

for (...)
   if (DbgStopPointInst *SP = dyn_cast<DbgStopPointInst>(Inst))
     std::cerr << "Loc: " << SP->getFileName() << ":" << SP->getLine() << "\n";

If you look at IntrinsicInst, you'll see methods to get the 
filename,directory,line#,col#, all packaged up into an easy to use class 
(some of Jim's excellent work :).


> On Apr 8, 2006, at 5:33 AM, John Trimble wrote:
>> Thanks for your help. I took a look at http://llvm.org/docs/ 
>> SourceLevelDebugging.html and it seems like this doesn't give you much in 
>> the way of line number information. If you know what source line you are 
>> interested in then you can set a breakpoint, but suppose you want to know 
>> the line number in the source code for some arbitrary bytecode instruction. 
>> In my particular case, I have a pass that finds bytecode instructions that 
>> represent indirect calls, now I want to find out what line number and 
>> source file that indirect call came from. Is there currently not a way to 
>> get this type of information? Thanks again.
>> - John Trimble
>> On 4/7/06, Reid Spencer <reid at x10sys.com> wrote:
>> The debug intrinsics are intended for that.  Please see:
>> http://llvm.org/docs/SourceLevelDebugging.html
>> for the details.
>> Please note that this is being worked on actively Jim Laskey at Apple.
>> He's working to get these intrinsics to generate DWARF output so that
>> LLVM generated code can be used with a debugger. However, the intrinsics
>> can be processed in whatever way you'd like via an LLVM pass.
>> Reid.
>> On Fri, 2006-04-07 at 14:59 -0700, John Trimble wrote:
>> > So if compile some file test.c and get some binary test.bc can I
>> > relate statements in test.bc with source code line numbers in test.c
>> > and if so how would I go about doing that. Thanks for your time.
>> >
>> Version: GnuPG v1.2.7 (GNU/Linux)
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