cmd/compile: interleave devirtualization and inlining

This CL interleaves devirtualization and inlining, so that
devirtualized calls can be inlined.

Fixes golang#52193.

Change-Id: I681e7c55bdb90ebf6df315d334e7a58f05110d9c
Reviewed-on: https://go-review.googlesource.com/c/go/+/528321
Auto-Submit: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Bypass: Matthew Dempsky <mdempsky@google.com>

Author: mdempsky

src/cmd/compile/internal/devirtualize/devirtualize.go

@@ -18,22 +18,9 @@ import (
 	"cmd/compile/internal/types"
 )
 
-// Static devirtualizes calls within fn where possible when the concrete callee
+// StaticCall devirtualizes the given call if possible when the concrete callee
 // is available statically.
-func Static(fn *ir.Func) {
-	ir.CurFunc = fn
-
-	ir.VisitList(fn.Body, func(n ir.Node) {
-		switch n := n.(type) {
-		case *ir.CallExpr:
-			staticCall(n)
-		}
-	})
-}
-
-// staticCall devirtualizes the given call if possible when the concrete callee
-// is available statically.
-func staticCall(call *ir.CallExpr) {
+func StaticCall(call *ir.CallExpr) {
 	// For promoted methods (including value-receiver methods promoted
 	// to pointer-receivers), the interface method wrapper may contain
 	// expressions that can panic (e.g., ODEREF, ODOTPTR,
@@ -51,6 +38,7 @@ func staticCall(call *ir.CallExpr) {
 	if call.Op() != ir.OCALLINTER {
 		return
 	}
+
 	sel := call.Fun.(*ir.SelectorExpr)
 	r := ir.StaticValue(sel.X)
 	if r.Op() != ir.OCONVIFACE {

src/cmd/compile/internal/gc/main.go

@@ -9,10 +9,10 @@ import (
 	"bytes"
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/coverage"
-	"cmd/compile/internal/devirtualize"
 	"cmd/compile/internal/dwarfgen"
 	"cmd/compile/internal/escape"
 	"cmd/compile/internal/inline"
+	"cmd/compile/internal/inline/interleaved"
 	"cmd/compile/internal/ir"
 	"cmd/compile/internal/logopt"
 	"cmd/compile/internal/loopvar"
@@ -224,30 +224,15 @@ func Main(archInit func(*ssagen.ArchInfo)) {
 		}
 	}
 
-	base.Timer.Start("fe", "pgo-devirtualization")
-	if profile != nil && base.Debug.PGODevirtualize > 0 {
-		// TODO(prattmic): No need to use bottom-up visit order. This
-		// is mirroring the PGO IRGraph visit order, which also need
-		// not be bottom-up.
-		ir.VisitFuncsBottomUp(typecheck.Target.Funcs, func(list []*ir.Func, recursive bool) {
-			for _, fn := range list {
-				devirtualize.ProfileGuided(fn, profile)
-			}
-		})
-		ir.CurFunc = nil
-	}
+	// Interleaved devirtualization and inlining.
+	base.Timer.Start("fe", "devirtualize-and-inline")
+	interleaved.DevirtualizeAndInlinePackage(typecheck.Target, profile)
 
-	// Inlining
-	base.Timer.Start("fe", "inlining")
-	if base.Flag.LowerL != 0 {
-		inline.InlinePackage(profile)
-	}
 	noder.MakeWrappers(typecheck.Target) // must happen after inlining
 
-	// Devirtualize and get variable capture right in for loops
+	// Get variable capture right in for loops.
 	var transformed []loopvar.VarAndLoop
 	for _, fn := range typecheck.Target.Funcs {
-		devirtualize.Static(fn)
 		transformed = append(transformed, loopvar.ForCapture(fn)...)
 	}
 	ir.CurFunc = nil