3 Commits

Author SHA1 Message Date
Easwaran Raman
efb87178ab [SyntheticCounts] Rewrite the code using only graph traits.
Summary:
The intent of this is to allow the code to be used with ThinLTO. In
Thinlink phase, a traditional Callgraph can not be computed even though
all the necessary information (nodes and edges of a call graph) is
available. This is due to the fact that CallGraph class is closely tied
to the IR. This patch first extends GraphTraits to add a CallGraphTraits
graph. This is then used to implement a version of counts propagation
on a generic callgraph.

Reviewers: davidxl

Subscribers: mehdi_amini, tejohnson, llvm-commits

Differential Revision: https://reviews.llvm.org/D42311

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@323475 91177308-0d34-0410-b5e6-96231b3b80d8
2018-01-25 22:02:29 +00:00
Easwaran Raman
fd335155cc Add a ProfileCount class to represent entry counts.
Summary:
The class wraps a uint64_t and an enum to represent the type of profile
count (real and synthetic) with some helper methods.

Reviewers: davidxl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D41883

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@322771 91177308-0d34-0410-b5e6-96231b3b80d8
2018-01-17 22:24:23 +00:00
Easwaran Raman
283d9781d9 Add a pass to generate synthetic function entry counts.
Summary:
This pass synthesizes function entry counts by traversing the callgraph
and using the relative block frequencies of the callsites. The intended
use of these counts is in inlining to determine hot/cold callsites in
the absence of profile information.

The pass is split into two files with the code that propagates the
counts in a callgraph in a Utils file. I plan to add support for
propagation in the thinlto link phase and the propagation code will be
shared and hence this split. I did not add support to the old PM since
hot callsite determination in inlining is not possible in old PM
(although we could use hot callee heuristic with synthetic counts in the
old PM it is not worth the effort tuning it)

Reviewers: davidxl, silvas

Subscribers: mgorny, mehdi_amini, llvm-commits

Differential Revision: https://reviews.llvm.org/D41604

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@322110 91177308-0d34-0410-b5e6-96231b3b80d8
2018-01-09 19:39:35 +00:00