cmd/compile: disable inlining functions with closures for now

Added a flag '-d=inlfuncswithclosures=1' to allow inlining functions with
closures, and change the default to off for now, until #44370 is fixed.

Updates #44370.

Change-Id: Ic17723aa5c091d91f5f5004d8b63ec7125257acf
Reviewed-on: https://go-review.googlesource.com/c/go/+/296049
Run-TryBot: Dan Scales <danscales@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Dan Scales <danscales@google.com>

src/cmd/compile/internal/base/debug.go

@@ -29,28 +29,29 @@ var Debug = DebugFlags{
 // The -d option takes a comma-separated list of settings.
 // Each setting is name=value; for ints, name is short for name=1.
 type DebugFlags struct {
-	Append        int    `help:"print information about append compilation"`
-	Checkptr      int    `help:"instrument unsafe pointer conversions"`
-	Closure       int    `help:"print information about closure compilation"`
-	DclStack      int    `help:"run internal dclstack check"`
-	Defer         int    `help:"print information about defer compilation"`
-	DisableNil    int    `help:"disable nil checks"`
-	DumpPtrs      int    `help:"show Node pointers values in dump output"`
-	DwarfInl      int    `help:"print information about DWARF inlined function creation"`
-	Export        int    `help:"print export data"`
-	Fieldtrack    *int   `help:"enable field tracking"`
-	GCProg        int    `help:"print dump of GC programs"`
-	Libfuzzer     int    `help:"enable coverage instrumentation for libfuzzer"`
-	LocationLists int    `help:"print information about DWARF location list creation"`
-	Nil           int    `help:"print information about nil checks"`
-	PCTab         string `help:"print named pc-value table"`
-	Panic         int    `help:"show all compiler panics"`
-	Slice         int    `help:"print information about slice compilation"`
-	SoftFloat     int    `help:"force compiler to emit soft-float code"`
-	TypeAssert    int    `help:"print information about type assertion inlining"`
-	TypecheckInl  int    `help:"eager typechecking of inline function bodies"`
-	WB            int    `help:"print information about write barriers"`
-	ABIWrap       int    `help:"print information about ABI wrapper generation"`
+	Append               int    `help:"print information about append compilation"`
+	Checkptr             int    `help:"instrument unsafe pointer conversions"`
+	Closure              int    `help:"print information about closure compilation"`
+	DclStack             int    `help:"run internal dclstack check"`
+	Defer                int    `help:"print information about defer compilation"`
+	DisableNil           int    `help:"disable nil checks"`
+	DumpPtrs             int    `help:"show Node pointers values in dump output"`
+	DwarfInl             int    `help:"print information about DWARF inlined function creation"`
+	Export               int    `help:"print export data"`
+	Fieldtrack           *int   `help:"enable field tracking"`
+	GCProg               int    `help:"print dump of GC programs"`
+	InlFuncsWithClosures int    `help:"allow functions with closures to be inlined"`
+	Libfuzzer            int    `help:"enable coverage instrumentation for libfuzzer"`
+	LocationLists        int    `help:"print information about DWARF location list creation"`
+	Nil                  int    `help:"print information about nil checks"`
+	PCTab                string `help:"print named pc-value table"`
+	Panic                int    `help:"show all compiler panics"`
+	Slice                int    `help:"print information about slice compilation"`
+	SoftFloat            int    `help:"force compiler to emit soft-float code"`
+	TypeAssert           int    `help:"print information about type assertion inlining"`
+	TypecheckInl         int    `help:"eager typechecking of inline function bodies"`
+	WB                   int    `help:"print information about write barriers"`
+	ABIWrap              int    `help:"print information about ABI wrapper generation"`
 
 	any bool // set when any of the values have been set
 }

src/cmd/compile/internal/inline/inl.go

@@ -354,15 +354,15 @@ func (v *hairyVisitor) doNode(n ir.Node) bool {
 		return true
 
 	case ir.OCLOSURE:
-		// TODO(danscales,mdempsky): Get working with -G.
-		// Probably after #43818 is fixed.
-		if base.Flag.G > 0 {
-			v.reason = "inlining closures not yet working with -G"
+		if base.Debug.InlFuncsWithClosures == 0 {
+			// TODO(danscales): change default of InlFuncsWithClosures
+			// to 1 when #44370 is fixed
+			v.reason = "not inlining functions with closures"
 			return true
 		}
 
-		// TODO(danscales) - fix some bugs when budget is lowered below 15
-		// Maybe make budget proportional to number of closure variables, e.g.:
+		// TODO(danscales): Maybe make budget proportional to number of closure
+		// variables, e.g.:
 		//v.budget -= int32(len(n.(*ir.ClosureExpr).Func.ClosureVars) * 3)
 		v.budget -= 15
 		// Scan body of closure (which DoChildren doesn't automatically

test/closure3.go

@@ -1,4 +1,4 @@
-// errorcheckandrundir -0 -m
+// errorcheckandrundir -0 -m -d=inlfuncswithclosures=1
 
 // Copyright 2017 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style

test/inline.go

@@ -1,4 +1,4 @@
-// errorcheck -0 -m
+// errorcheck -0 -m -d=inlfuncswithclosures=1
 
 // Copyright 2015 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style