[dev.typeparams] all: merge dev.regabi (063c72f) into dev.typeparams

Eager re-sync-branch to keep Git history reasonably accurate, since
Git lacks a better way of encoding partial merges like CL 286172.

Conflicts:

- src/cmd/compile/internal/inline/inl.go
- src/cmd/compile/internal/noder/import.go
- src/cmd/compile/internal/noder/noder.go

Merge List:

+ 2021-01-25 063c72f06d [dev.regabi] cmd/compile: backport changes from dev.typeparams (9456804)
+ 2021-01-23 d05d6fab32 [dev.regabi] cmd/compile: replace ir.Name map with ir.NameSet for SSA 2
+ 2021-01-23 48badc5fa8 [dev.regabi] cmd/compile: fix escape analysis problem with closures
+ 2021-01-23 51e1819a8d [dev.regabi] cmd/compile: scan body of closure in tooHairy to check for disallowed nodes

Change-Id: I48c0435f7aaf56f4aec26518a7459e9d95a51e9c

src/cmd/compile/internal/escape/escape.go

@@ -781,6 +781,16 @@ func (e *escape) exprSkipInit(k hole, n ir.Node) {
 				}
 			}
 
+			for _, n := range fn.Dcl {
+				// Add locations for local variables of the
+				// closure, if needed, in case we're not including
+				// the closure func in the batch for escape
+				// analysis (happens for escape analysis called
+				// from reflectdata.methodWrapper)
+				if n.Op() == ir.ONAME && n.Opt == nil {
+					e.with(fn).newLoc(n, false)
+				}
+			}
 			e.walkFunc(fn)
 		}
 

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

@@ -361,10 +361,16 @@ func (v *hairyVisitor) doNode(n ir.Node) bool {
 			return true
 		}
 
-		// TODO(danscales) - fix some bugs when budget is lowered below 30
+		// TODO(danscales) - fix some bugs when budget is lowered below 15
 		// Maybe make budget proportional to number of closure variables, e.g.:
 		//v.budget -= int32(len(n.(*ir.ClosureExpr).Func.ClosureVars) * 3)
-		v.budget -= 30
+		v.budget -= 15
+		// Scan body of closure (which DoChildren doesn't automatically
+		// do) to check for disallowed ops in the body and include the
+		// body in the budget.
+		if doList(n.(*ir.ClosureExpr).Func.Body, v.do) {
+			return true
+		}
 
 	case ir.ORANGE,
 		ir.OSELECT,

src/cmd/compile/internal/noder/import.go

@@ -176,6 +176,11 @@ func resolveImportPath(path string) (string, error) {
 
 // TODO(mdempsky): Return an error instead.
 func importfile(decl *syntax.ImportDecl) *types.Pkg {
+	if decl.Path.Kind != syntax.StringLit {
+		base.Errorf("import path must be a string")
+		return nil
+	}
+
 	path, err := strconv.Unquote(decl.Path.Value)
 	if err != nil {
 		base.Errorf("import path must be a string")

src/cmd/compile/internal/ssa/deadstore.go

@@ -299,7 +299,7 @@ func elimUnreadAutos(f *Func) {
 	// Loop over all ops that affect autos taking note of which
 	// autos we need and also stores that we might be able to
 	// eliminate.
-	seen := make(map[*ir.Name]bool)
+	var seen ir.NameSet
 	var stores []*Value
 	for _, b := range f.Blocks {
 		for _, v := range b.Values {
@@ -317,7 +317,7 @@ func elimUnreadAutos(f *Func) {
 				// If we haven't seen the auto yet
 				// then this might be a store we can
 				// eliminate.
-				if !seen[n] {
+				if !seen.Has(n) {
 					stores = append(stores, v)
 				}
 			default:
@@ -327,7 +327,7 @@ func elimUnreadAutos(f *Func) {
 				// because dead loads haven't been
 				// eliminated yet.
 				if v.Uses > 0 {
-					seen[n] = true
+					seen.Add(n)
 				}
 			}
 		}
@@ -336,7 +336,7 @@ func elimUnreadAutos(f *Func) {
 	// Eliminate stores to unread autos.
 	for _, store := range stores {
 		n, _ := store.Aux.(*ir.Name)
-		if seen[n] {
+		if seen.Has(n) {
 			continue
 		}
 

test/closure6.go

@@ -0,0 +1,18 @@
+// compile
+
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package p
+
+type Float64Slice []float64
+
+func (a Float64Slice) Search1(x float64) int {
+	f := func(q int) bool { return a[q] >= x }
+	i := 0
+	if !f(3) {
+		i = 5
+	}
+	return i
+}