cmd/compile,cmd/preprofile: move logic to shared common package

The processing performed in cmd/preprofile is a simple version of the
same initial processing performed by cmd/compile/internal/pgo. Refactor
this processing into the new IR-independent cmd/internal/pgo package.

Now cmd/preprofile and cmd/compile run the same code for initial
processing of a pprof profile, guaranteeing that they always stay in
sync.

Since it is now trivial, this CL makes one change to the serialization
format: the entries are ordered by weight. This allows us to avoid
sorting ByWeight on deserialization.

Impact on PGO parsing when compiling cmd/compile with PGO:

* Without preprocessing: PGO parsing ~13.7% of CPU time
* With preprocessing (unsorted): ~2.9% of CPU time (sorting ~1.7%)
* With preprocessing (sorted): ~1.3% of CPU time

The remaining 1.3% of CPU time approximately breaks down as:

* ~0.5% parsing the preprocessed profile
* ~0.7% building weighted IR call graph
  * ~0.5% walking function IR to find direct calls
  * ~0.2% performing lookups for indirect calls targets

For #58102.

Change-Id: Iaba425ea30b063ca195fb2f7b29342961c8a64c2
Reviewed-on: https://go-review.googlesource.com/c/go/+/569337
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Michael Pratt <mpratt@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>

1 files changed, 31 insertions, 31 deletions

diff --git a/src/cmd/compile/internal/test/testdata/pgo/devirtualize/devirt.pprof.node_map b/src/cmd/compile/internal/test/testdata/pgo/devirtualize/devirt.pprof.node_map
index c55f990e84..1bb6a80f06 100644
--- a/src/cmd/compile/internal/test/testdata/pgo/devirtualize/devirt.pprof.node_map
+++ b/src/cmd/compile/internal/test/testdata/pgo/devirtualize/devirt.pprof.node_map
@@ -1,52 +1,52 @@
 GO PREPROFILE V1
-example.com/pgo/devirtualize.ExerciseFuncClosure
-example.com/pgo/devirtualize/mult%2epkg.MultClosure.func1
-18 93
-example.com/pgo/devirtualize.ExerciseIface
-example.com/pgo/devirtualize/mult%2epkg.NegMult.Multiply
-49 4
 example.com/pgo/devirtualize.ExerciseFuncConcrete
 example.com/pgo/devirtualize.AddFn
 48 103
 example.com/pgo/devirtualize.ExerciseFuncField
-example.com/pgo/devirtualize/mult%2epkg.NegMultFn
-23 8
+example.com/pgo/devirtualize.AddFn
+23 101
 example.com/pgo/devirtualize.ExerciseFuncField
 example.com/pgo/devirtualize/mult%2epkg.MultFn
 23 94
-example.com/pgo/devirtualize.ExerciseIface
-example.com/pgo/devirtualize/mult%2epkg.Mult.Multiply
-49 40
+example.com/pgo/devirtualize.ExerciseFuncClosure
+example.com/pgo/devirtualize/mult%2epkg.MultClosure.func1
+18 93
+example.com/pgo/devirtualize.ExerciseFuncClosure
+example.com/pgo/devirtualize.Add.Add
+18 92
+example.com/pgo/devirtualize.ExerciseFuncConcrete
+example.com/pgo/devirtualize/mult%2epkg.MultFn
+48 91
 example.com/pgo/devirtualize.ExerciseIface
 example.com/pgo/devirtualize.Add.Add
 49 55
-example.com/pgo/devirtualize.ExerciseFuncConcrete
-example.com/pgo/devirtualize/mult%2epkg.NegMultFn
-48 8
+example.com/pgo/devirtualize.ExerciseIface
+example.com/pgo/devirtualize/mult%2epkg.Mult.Multiply
+49 40
+example.com/pgo/devirtualize.ExerciseFuncClosure
+example.com/pgo/devirtualize.Sub.Add
+18 14
+example.com/pgo/devirtualize.ExerciseFuncField
+example.com/pgo/devirtualize.SubFn
+23 12
 example.com/pgo/devirtualize.ExerciseFuncClosure
 example.com/pgo/devirtualize/mult%2epkg.NegMultClosure.func1
 18 10
+example.com/pgo/devirtualize.ExerciseFuncConcrete
+example.com/pgo/devirtualize/mult%2epkg.NegMultFn
+48 8
+example.com/pgo/devirtualize.ExerciseFuncField
+example.com/pgo/devirtualize/mult%2epkg.NegMultFn
+23 8
 example.com/pgo/devirtualize.ExerciseIface
 example.com/pgo/devirtualize.Sub.Add
 49 7
-example.com/pgo/devirtualize.ExerciseFuncField
-example.com/pgo/devirtualize.AddFn
-23 101
-example.com/pgo/devirtualize.ExerciseFuncField
+example.com/pgo/devirtualize.ExerciseFuncConcrete
 example.com/pgo/devirtualize.SubFn
-23 12
+48 5
+example.com/pgo/devirtualize.ExerciseIface
+example.com/pgo/devirtualize/mult%2epkg.NegMult.Multiply
+49 4
 example.com/pgo/devirtualize.BenchmarkDevirtFuncConcrete
 example.com/pgo/devirtualize.ExerciseFuncConcrete
 1 2
-example.com/pgo/devirtualize.ExerciseFuncConcrete
-example.com/pgo/devirtualize/mult%2epkg.MultFn
-48 91
-example.com/pgo/devirtualize.ExerciseFuncConcrete
-example.com/pgo/devirtualize.SubFn
-48 5
-example.com/pgo/devirtualize.ExerciseFuncClosure
-example.com/pgo/devirtualize.Add.Add
-18 92
-example.com/pgo/devirtualize.ExerciseFuncClosure
-example.com/pgo/devirtualize.Sub.Add
-18 14