[dev.typeparams] all: merge dev.regabi (07569da) into dev.typeparams

Conflicts:

- test/fixedbugs/issue27595.go
- test/fixedbugs/issue30087.go
- test/used.go

Merge List:

+ 2020-12-28 07569da [dev.regabi] all: merge master (1d78139) into dev.regabi
+ 2020-12-28 76136be [dev.regabi] cmd/compile: check for recursive import in ImportBody
+ 2020-12-28 fda7ec3 [dev.regabi] cmd/compile: remove Name.IsDDD, etc
+ 2020-12-28 098a649 [dev.regabi] cmd/compile: remove Declare in makepartialcall
+ 2020-12-28 137f0d2 [dev.regabi] cmd/compile: remove unnecessary Name.Sym call
+ 2020-12-28 3383b5c [dev.regabi] cmd/compile: flatten dependency graph [generated]
+ 2020-12-28 f8afb82 [dev.regabi] cmd/compile: rename CommStmt and CaseStmt [generated]
+ 2020-12-28 5f3bd59 [dev.regabi] cmd/compile: remove some unneeded code in package ir
+ 2020-12-28 3bdafb0 [dev.regabi] cmd/compile: remove CommStmt.List
+ 2020-12-28 2ecf52b [dev.regabi] cmd/compile: separate CommStmt from CaseStmt
+ 2020-12-28 ed9772e [dev.regabi] cmd/compile: add explicit file name in types generation
+ 2020-12-28 a59d266 [dev.regabi] cmd/compile: use []*CaseStmt in {Select,Switch}Stmt
+ 2020-12-28 fbc4458 [dev.regabi] cmd/compile: simplify some tree traversal code
+ 2020-12-28 6c67677 [dev.regabi] cmd/compile: simplify FuncName and PkgFuncName
+ 2020-12-28 676d794 [dev.regabi] cmd/compile: remove refersToCommonName
+ 2020-12-28 c98548e [dev.regabi] cmd/compile: merge ascompatee, ascompatee1, and reorder3
+ 2020-12-28 4c215c4 [dev.regabi] cmd/compile: simplify and optimize reorder3
+ 2020-12-28 e6c9731 [dev.regabi] cmd/compile: stop mangling SelectorExpr.Sel for ODOTMETH
+ 2020-12-28 135ce1c [dev.regabi] cmd/compile: desugar OMETHEXPR into ONAME during walk
+ 2020-12-28 0f732f8 [dev.regabi] cmd/compile: minor walkExpr cleanups
+ 2020-12-28 0de8eaf [dev.regabi] cmd/compile: remove SelectorExpr.Offset field
+ 2020-12-28 a4f335f [dev.regabi] cmd/compile: always use a Field for ODOTPTR expressions
+ 2020-12-26 1d78139 runtime/cgo: fix Android build with NDK 22
+ 2020-12-25 2018b68 net/mail: don't use MDT in test
+ 2020-12-25 e4f293d [dev.regabi] cmd/compile: fix OCALLMETH desugaring
+ 2020-12-25 1d9a1f6 [dev.regabi] cmd/compile: don't emit reflect data for method types
+ 2020-12-25 396b6c2 [dev.regabi] cmd/compile: cleanup assignment typechecking
+ 2020-12-25 e24d2f3 [dev.regabi] cmd/compile: remove typ from RangeStmt
+ 2020-12-25 2785c69 [dev.regabi] cmd/compile: cleanup devirtualization docs
+ 2020-12-25 4b1d0fe [dev.regabi] cmd/compile: new devirtualization pkg [generated]
+ 2020-12-24 082cc8b [dev.regabi] cmd/compile: change ir.IsAssignable -> ir.IsAddressable
+ 2020-12-24 27b248b [dev.regabi] cmd/compile: separate range stmt Vars to Key, Value nodes
+ 2020-12-23 4081803 [dev.regabi] cmd/compile: change CaseStmt.Vars to Var
+ 2020-12-23 b116404 runtime: shift timeHistogram buckets and allow negative durations
+ 2020-12-23 8db7e2f runtime: fix allocs-by-size and frees-by-size buckets
+ 2020-12-23 fb96f07 runtime: fix nStackRoots comment about stack roots
+ 2020-12-23 d1502b3 lib/time, time/tzdata: update tzdata to 2020e
+ 2020-12-23 30c99cb cmd/go: add the Retract field to 'go help mod edit' definition of the GoMod struct
+ 2020-12-23 49d0b23 doc: fix a typo in contribute.html
+ 2020-12-23 9eeed29 [dev.regabi] cmd/compile: eliminate usage of ir.Node in liveness
+ 2020-12-23 d1d64e4 [dev.regabi] cmd/compile: split SliceExpr.List into separate fields
+ 2020-12-23 98a7303 cmd/go: in 'go get', promote named implicit dependencies to explicit
+ 2020-12-23 d19018e [dev.regabi] cmd/compile: split SliceHeaderExpr.LenCap into separate fields
+ 2020-12-23 53f082b [dev.regabi] cmd/compile: cleanup export code further
+ 2020-12-23 31267f8 [dev.regabi] cmd/compile: simplify function/interface/struct typechecking
+ 2020-12-23 addade2 [dev.regabi] cmd/compile: prefer types constructors over typecheck
+ 2020-12-23 18ebfb4 [dev.regabi] cmd/compile: cleanup noder
+ 2020-12-23 87a592b [dev.regabi] cmd/compile: cleanup import/export code
+ 2020-12-23 5898025 [dev.regabi] cmd/compile: update mkbuiltin.go to use new type constructors
+ 2020-12-23 63c96c2 [dev.regabi] cmd/compile: update mkbuiltin.go and re-enable TestBuiltin
+ 2020-12-23 fd6ba1c os/signal: fix a deadlock with syscall.AllThreadsSyscall() use
+ 2020-12-23 b0b0d98 runtime: linux iscgo support for not blocking nptl signals
+ 2020-12-22 223331f cmd/go/internal/modload: add hint for missing implicit dependency

Change-Id: Iecb8a7dfb401b6ab383e97101cd81bfc201683f6

doc/contribute.html

@@ -1129,7 +1129,7 @@ <h3 id="quick_test">Quickly testing your changes</h3>
 might require a newer version than the stable one you have installed).
 
 <pre>
-$ cd $GODIR/src/hash/sha1
+$ cd $GODIR/src/crypto/sha1
 $ [make changes...]
 $ $GODIR/bin/go test .
 </pre>

lib/time/update.bash

@@ -8,8 +8,8 @@
 # Consult https://www.iana.org/time-zones for the latest versions.
 
 # Versions to use.
-CODE=2020d
-DATA=2020d
+CODE=2020e
+DATA=2020e
 
 set -e
 rm -rf work

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

@@ -0,0 +1,85 @@
+// 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 devirtualize implements a simple "devirtualization"
+// optimization pass, which replaces interface method calls with
+// direct concrete-type method calls where possible.
+package devirtualize
+
+import (
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/typecheck"
+	"cmd/compile/internal/types"
+)
+
+// Func devirtualizes calls within fn where possible.
+func Func(fn *ir.Func) {
+	ir.CurFunc = fn
+	ir.VisitList(fn.Body, func(n ir.Node) {
+		if call, ok := n.(*ir.CallExpr); ok {
+			Call(call)
+		}
+	})
+}
+
+// Call devirtualizes the given call if possible.
+func Call(call *ir.CallExpr) {
+	if call.Op() != ir.OCALLINTER {
+		return
+	}
+	sel := call.X.(*ir.SelectorExpr)
+	r := ir.StaticValue(sel.X)
+	if r.Op() != ir.OCONVIFACE {
+		return
+	}
+	recv := r.(*ir.ConvExpr)
+
+	typ := recv.X.Type()
+	if typ.IsInterface() {
+		return
+	}
+
+	dt := ir.NewTypeAssertExpr(sel.Pos(), sel.X, nil)
+	dt.SetType(typ)
+	x := typecheck.Callee(ir.NewSelectorExpr(sel.Pos(), ir.OXDOT, dt, sel.Sel))
+	switch x.Op() {
+	case ir.ODOTMETH:
+		x := x.(*ir.SelectorExpr)
+		if base.Flag.LowerM != 0 {
+			base.WarnfAt(call.Pos(), "devirtualizing %v to %v", sel, typ)
+		}
+		call.SetOp(ir.OCALLMETH)
+		call.X = x
+	case ir.ODOTINTER:
+		// Promoted method from embedded interface-typed field (#42279).
+		x := x.(*ir.SelectorExpr)
+		if base.Flag.LowerM != 0 {
+			base.WarnfAt(call.Pos(), "partially devirtualizing %v to %v", sel, typ)
+		}
+		call.SetOp(ir.OCALLINTER)
+		call.X = x
+	default:
+		// TODO(mdempsky): Turn back into Fatalf after more testing.
+		if base.Flag.LowerM != 0 {
+			base.WarnfAt(call.Pos(), "failed to devirtualize %v (%v)", x, x.Op())
+		}
+		return
+	}
+
+	// Duplicated logic from typecheck for function call return
+	// value types.
+	//
+	// Receiver parameter size may have changed; need to update
+	// call.Type to get correct stack offsets for result
+	// parameters.
+	types.CheckSize(x.Type())
+	switch ft := x.Type(); ft.NumResults() {
+	case 0:
+	case 1:
+		call.SetType(ft.Results().Field(0).Type)
+	default:
+		call.SetType(ft.Results())
+	}
+}

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

@@ -347,21 +347,19 @@ func (e *escape) stmt(n ir.Node) {
 		e.loopDepth--
 
 	case ir.ORANGE:
-		// for List = range Right { Nbody }
+		// for Key, Value = range X { Body }
 		n := n.(*ir.RangeStmt)
 		e.loopDepth++
-		ks := e.addrs(n.Vars)
+		e.addr(n.Key)
+		k := e.addr(n.Value)
 		e.block(n.Body)
 		e.loopDepth--
 
-		// Right is evaluated outside the loop.
-		k := e.discardHole()
-		if len(ks) >= 2 {
-			if n.X.Type().IsArray() {
-				k = ks[1].note(n, "range")
-			} else {
-				k = ks[1].deref(n, "range-deref")
-			}
+		// X is evaluated outside the loop.
+		if n.X.Type().IsArray() {
+			k = k.note(n, "range")
+		} else {
+			k = k.deref(n, "range-deref")
 		}
 		e.expr(e.later(k), n.X)
 
@@ -371,9 +369,8 @@ func (e *escape) stmt(n ir.Node) {
 
 		var ks []hole
 		for _, cas := range n.Cases { // cases
-			cas := cas.(*ir.CaseStmt)
 			if typesw && n.Tag.(*ir.TypeSwitchGuard).Tag != nil {
-				cv := cas.Vars[0]
+				cv := cas.Var
 				k := e.dcl(cv) // type switch variables have no ODCL.
 				if cv.Type().HasPointers() {
 					ks = append(ks, k.dotType(cv.Type(), cas, "switch case"))
@@ -393,7 +390,6 @@ func (e *escape) stmt(n ir.Node) {
 	case ir.OSELECT:
 		n := n.(*ir.SelectStmt)
 		for _, cas := range n.Cases {
-			cas := cas.(*ir.CaseStmt)
 			e.stmt(cas.Comm)
 			e.block(cas.Body)
 		}
@@ -559,10 +555,9 @@ func (e *escape) exprSkipInit(k hole, n ir.Node) {
 	case ir.OSLICE, ir.OSLICEARR, ir.OSLICE3, ir.OSLICE3ARR, ir.OSLICESTR:
 		n := n.(*ir.SliceExpr)
 		e.expr(k.note(n, "slice"), n.X)
-		low, high, max := n.SliceBounds()
-		e.discard(low)
-		e.discard(high)
-		e.discard(max)
+		e.discard(n.Low)
+		e.discard(n.High)
+		e.discard(n.Max)
 
 	case ir.OCONV, ir.OCONVNOP:
 		n := n.(*ir.ConvExpr)

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

@@ -10,6 +10,7 @@ import (
 	"bufio"
 	"bytes"
 	"cmd/compile/internal/base"
+	"cmd/compile/internal/devirtualize"
 	"cmd/compile/internal/dwarfgen"
 	"cmd/compile/internal/escape"
 	"cmd/compile/internal/inline"
@@ -243,7 +244,7 @@ func Main(archInit func(*ssagen.ArchInfo)) {
 	// Devirtualize.
 	for _, n := range typecheck.Target.Decls {
 		if n.Op() == ir.ODCLFUNC {
-			inline.Devirtualize(n.(*ir.Func))
+			devirtualize.Func(n.(*ir.Func))
 		}
 	}
 	ir.CurFunc = nil

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

@@ -324,19 +324,17 @@ func (v *hairyVisitor) doNode(n ir.Node) error {
 		if t == nil {
 			base.Fatalf("no function type for [%p] %+v\n", n.X, n.X)
 		}
-		if types.IsRuntimePkg(n.X.Sym().Pkg) {
-			fn := n.X.Sym().Name
-			if fn == "heapBits.nextArena" {
-				// Special case: explicitly allow
-				// mid-stack inlining of
-				// runtime.heapBits.next even though
-				// it calls slow-path
-				// runtime.heapBits.nextArena.
-				break
-			}
+		fn := ir.MethodExprName(n.X).Func
+		if types.IsRuntimePkg(fn.Sym().Pkg) && fn.Sym().Name == "heapBits.nextArena" {
+			// Special case: explicitly allow
+			// mid-stack inlining of
+			// runtime.heapBits.next even though
+			// it calls slow-path
+			// runtime.heapBits.nextArena.
+			break
 		}
-		if inlfn := ir.MethodExprName(n.X).Func; inlfn.Inl != nil {
-			v.budget -= inlfn.Inl.Cost
+		if fn.Inl != nil {
+			v.budget -= fn.Inl.Cost
 			break
 		}
 		// Call cost for non-leaf inlining.
@@ -531,7 +529,7 @@ func inlnode(n ir.Node, maxCost int32, inlMap map[*ir.Func]bool, edit func(ir.No
 		// Prevent inlining some reflect.Value methods when using checkptr,
 		// even when package reflect was compiled without it (#35073).
 		n := n.(*ir.CallExpr)
-		if s := n.X.Sym(); base.Debug.Checkptr != 0 && types.IsReflectPkg(s.Pkg) && (s.Name == "Value.UnsafeAddr" || s.Name == "Value.Pointer") {
+		if s := ir.MethodExprName(n.X).Sym(); base.Debug.Checkptr != 0 && types.IsReflectPkg(s.Pkg) && (s.Name == "Value.UnsafeAddr" || s.Name == "Value.Pointer") {
 			return n
 		}
 	}
@@ -1203,73 +1201,6 @@ func pruneUnusedAutos(ll []*ir.Name, vis *hairyVisitor) []*ir.Name {
 	return s
 }
 
-// Devirtualize replaces interface method calls within fn with direct
-// concrete-type method calls where applicable.
-func Devirtualize(fn *ir.Func) {
-	ir.CurFunc = fn
-	ir.VisitList(fn.Body, func(n ir.Node) {
-		if n.Op() == ir.OCALLINTER {
-			devirtualizeCall(n.(*ir.CallExpr))
-		}
-	})
-}
-
-func devirtualizeCall(call *ir.CallExpr) {
-	sel := call.X.(*ir.SelectorExpr)
-	r := ir.StaticValue(sel.X)
-	if r.Op() != ir.OCONVIFACE {
-		return
-	}
-	recv := r.(*ir.ConvExpr)
-
-	typ := recv.X.Type()
-	if typ.IsInterface() {
-		return
-	}
-
-	dt := ir.NewTypeAssertExpr(sel.Pos(), sel.X, nil)
-	dt.SetType(typ)
-	x := typecheck.Callee(ir.NewSelectorExpr(sel.Pos(), ir.OXDOT, dt, sel.Sel))
-	switch x.Op() {
-	case ir.ODOTMETH:
-		x := x.(*ir.SelectorExpr)
-		if base.Flag.LowerM != 0 {
-			base.WarnfAt(call.Pos(), "devirtualizing %v to %v", sel, typ)
-		}
-		call.SetOp(ir.OCALLMETH)
-		call.X = x
-	case ir.ODOTINTER:
-		// Promoted method from embedded interface-typed field (#42279).
-		x := x.(*ir.SelectorExpr)
-		if base.Flag.LowerM != 0 {
-			base.WarnfAt(call.Pos(), "partially devirtualizing %v to %v", sel, typ)
-		}
-		call.SetOp(ir.OCALLINTER)
-		call.X = x
-	default:
-		// TODO(mdempsky): Turn back into Fatalf after more testing.
-		if base.Flag.LowerM != 0 {
-			base.WarnfAt(call.Pos(), "failed to devirtualize %v (%v)", x, x.Op())
-		}
-		return
-	}
-
-	// Duplicated logic from typecheck for function call return
-	// value types.
-	//
-	// Receiver parameter size may have changed; need to update
-	// call.Type to get correct stack offsets for result
-	// parameters.
-	types.CheckSize(x.Type())
-	switch ft := x.Type(); ft.NumResults() {
-	case 0:
-	case 1:
-		call.SetType(ft.Results().Field(0).Type)
-	default:
-		call.SetType(ft.Results())
-	}
-}
-
 // numNonClosures returns the number of functions in list which are not closures.
 func numNonClosures(list []*ir.Func) int {
 	count := 0