[llvm-commits] JIT: Emitting a debug location after an instruction

[nicolas geoffray]

On Mon, Aug 23, 2010 at 2:57 PM, Jeffrey Yasskin <jyasskin at google.com>wrote:

>
> Do you _only_ attach line information to calls, or also to each other
> instruction?


I only attach line (or more precisely metadata) information to calls.



> If it's only to the calls, do you just not provide line
> numbers for the leaf frame? If you do provide line numbers for the
> leaf frame, are you worried about providing the wrong number just
> after returning from a call?
>

I don't have leaf frames.


>
> The line number debug information is generally compressed into a table
> of (address, line) pairs, sorted by the address. Then you search the
> leaf frame using "std::upper_bound(table, PC)-1".


The code that looks up the method from the PC is performance sensitive, so
using upper_bound is not ideal.

Nicolas
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