[llvm-commits] [PATCH 2/4] Profile metadata: Profile loader

[Manman Ren]

Hi Alastair,

Thanks for the patch. It looks good.

I have a few comments:
1> I prefer doxygen comment block for the classes and functions :)
2> Should we get rid of "; preds " in your testing cases?
3> Should we also update ProfileVerifierPass to use ProfileDataT instead of ProfileInfoT?
4> Can we update the definition of an edge here?
+class ProfileDataT {
+  public:
+  // The profiling information defines an Edge by its source and sink basic
+  // blocks.
+  typedef std::pair<const BType*, const BType*> Edge;
+
+  private:
+  typedef std::map<Edge, unsigned> EdgeWeights;

In the following example:
  for (int i = 0; i < STRLEN; ++i)
    for (int j = 0; j < STRLEN; ++j)
      switch(strs[i][j]) {
      default:
        sum += strs[i][j];
        break;
      case 0:
      case 1:
      case 2:
        // Trying to make the counter different for these 3 cases.
        sum += strs[i][j] * 2;
        break;
      case 5:
        sum += strs[i][j] * 4;
        break;
      }

We will have 3 counters from the switch block to the target of case 0, case 1 and case 2, but I believe the old ProfileInfo and your implementation
will associate the same weight for the three cases. Since all 3 edges are between the same pair of blocks, we can't tell the difference with edge
defined as a pair of blocks.

That said, I am okay with submitting additional patches to fix 3) and 4) later on.

Thanks,
Manman

On Aug 18, 2012, at 6:37 AM, Alastair Murray wrote:

> Hello all,
> 
> Please review the attached patch.
> 
> This is the second of four patches to support setting branch weight metadata by profiling.  It depends on the first patch.
> 
> There are also three binary profile data files attached that are used for testing, these should go in test/Analysis/Profiling.
> 
> This patch implements the profile loader which can load profile data generated by programs compiled with "-insert-edge-profiling".  It also provides tests and moves three function definitions out of ProfileInfo into the new profiling code.  The pass is invoked by "-profile-metadata-loader", but I believe that once ProfileInfo etc. is removed it should take over the "-profile-loader" switch that that currently uses.
> 
> The attached patch has been cleaned up a little from the version sent to llvm-dev last week, some class renaming, commenting etc.  It is largely the same in logical terms though.
> 
> It has been tested via the attached tests and by '-profile-metadata-loader -std-compile-opts' over test-suite (using the Makefile to come in patch #4).
> 
> Regards,
> Alastair.
> <weights_2_profiler_loader.patch><load-branch-weights-ifs.ll.prof_data><load-branch-weights-loops.ll.prof_data><load-branch-weights-switches.ll.prof_data>_______________________________________________
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