[release-branch.go1.17] all: merge master (b8ca6e5) into release-branch.go1.17

Merge List:

+ 2021-07-31 b8ca6e5 all: gofmt
+ 2021-07-30 b7a85e0 net/http/httputil: close incoming ReverseProxy request body
+ 2021-07-29 70fd4e4 runtime: avoid possible preemption when returning from Go to C
+ 2021-07-28 9eee0ed cmd/go: fix go.mod file name printed in error messages for replacements
+ 2021-07-28 b39e0f4 runtime: don't crash on nil pointers in checkptrAlignment
+ 2021-07-27 7cd10c1 cmd/go: use .mod instead of .zip to determine if version has go.mod file
+ 2021-07-27 c8cf0f7 cmd/go: add missing flag in UsageLine
+ 2021-07-27 7ba8e79 testing: clarify T.Name returns a distinct name of the running test
+ 2021-07-27 33ff155 go/types: preserve untyped constants on the RHS of a shift expression
+ 2021-07-26 840e583 runtime: correct variable name in comment
+ 2021-07-26 bfbb288 runtime: remove adjustTimers counter
+ 2021-07-26 9c81fd5 cmd/vet: add missing copyright header
+ 2021-07-26 ecaa681 doc: clarify non-nil zero length slice to array pointer conversion
+ 2021-07-26 1868f82 crypto/x509: update iOS bundled roots to version 55188.120.1.0.1
+ 2021-07-25 849b791 spec: use consistent capitalization for rune literal hex constants
+ 2021-07-23 0914646 doc/1.17: fix two dead rfc links
+ 2021-07-22 052da57 cmd/compile: do not change field offset in ABI analysis
+ 2021-07-22 798ec73 runtime: don't clear timerModifiedEarliest if adjustTimers is 0
+ 2021-07-22 fdb45ac runtime: move mem profile sampling into m-acquired section
+ 2021-07-21 3e48c03 reflect: add missing copyright header
+ 2021-07-21 48c88f1 reflect: add Value.CanConvert
+ 2021-07-20 9e26569 cmd/go: don't add C compiler ID to hash for standard library
+ 2021-07-20 d568e6e runtime/debug: skip TestPanicOnFault on netbsd/arm
+ 2021-07-19 c8f4e61 spec: correct example comment in Conversions from slice to array
+ 2021-07-19 1d91551 time: correct typo in documentation for UnixMicro
+ 2021-07-19 404127c cmd/compile: fix off-by-one error in traceback argument counting
+ 2021-07-19 6298cfe cmd/compile: fix typo in fatal message of builtinCall
+ 2021-07-19 49402be cmd/{compile,link}: fix bug in map.zero handling
+ 2021-07-18 a66190e test/bench/go1: fix size for RegexpMatchMedium_32
+ 2021-07-18 650fc21 text/scanner: use Go convention in Position doc comment
+ 2021-07-16 aa4e0f5 net/http:  correct capitalization in cancelTimeBody comment
+ 2021-07-15 0941dbc testing: clarify in docs that TestMain is advanced
+ 2021-07-15 69728ea cmd/go: update error messages in tests to match CL 332573
+ 2021-07-15 c1cc9f9 cmd/compile: fix lookup package of redeclared dot import symbol
+ 2021-07-15 21a04e3 doc/go1.17: mention GOARCH=loong64
+ 2021-07-14 2b00a54 go/build, runtime/internal/sys: reserve GOARCH=loong64
+ 2021-07-14 60ddf42 cmd/go: change link in error message from /wiki to /doc.
+ 2021-07-13 d8f348a cmd/go: remove a duplicated word from 'go help mod graph'

Change-Id: I63a540ba823bcbde7249348999ac5a7d9908b531

Author: toothrot

api/go1.17.txt

@@ -80,6 +80,7 @@ pkg net/url, method (Values) Has(string) bool
 pkg reflect, func VisibleFields(Type) []StructField
 pkg reflect, method (Method) IsExported() bool
 pkg reflect, method (StructField) IsExported() bool
+pkg reflect, method (Value) CanConvert(Type) bool
 pkg runtime/cgo (darwin-amd64-cgo), func NewHandle(interface{}) Handle
 pkg runtime/cgo (darwin-amd64-cgo), method (Handle) Delete()
 pkg runtime/cgo (darwin-amd64-cgo), method (Handle) Value() interface{}

doc/go1.17.html

@@ -119,6 +119,17 @@ <h3 id="arm64">ARM64</h3>
   stack frame pointers only on Linux, macOS, and iOS.
 </p>
 
+<h3 id="loong64">loong64 GOARCH value reserved</h3>
+
+<p><!-- CL 333909 -->
+  The main Go compiler does not yet support the LoongArch
+  architecture, but we've reserved the <code>GOARCH</code> value
+  "<code>loong64</code>".
+  This means that Go files named <code>*_loong64.go</code> will now
+  be <a href="/pkg/go/build/#hdr-Build_Constraints">ignored by Go
+  tools</a> except when that GOARCH value is being used.
+</p>
+
 <h2 id="tools">Tools</h2>
 
 <h3 id="go-command">Go command</h3>
@@ -875,8 +886,8 @@ <h3 id="minor_library_changes">Minor changes to the library</h3>
   <dd>
     <p><!-- CL 272668 -->
       The new method <a href="/pkg/net/#IP.IsPrivate"><code>IP.IsPrivate</code></a> reports whether an address is
-      a private IPv4 address according to <a href="http://tools.ietf.org/html/rfc1918">RFC 1918</a>
-      or a local IPv6 address according <a href="http://tools.ietf.org/html/rfc4193">RFC 4193</a>.
+      a private IPv4 address according to <a href="https://datatracker.ietf.org/doc/rfc1918">RFC 1918</a>
+      or a local IPv6 address according <a href="https://datatracker.ietf.org/doc/rfc4193">RFC 4193</a>.
     </p>
 
     <p><!-- CL 301709 -->
@@ -978,6 +989,18 @@ <h3 id="minor_library_changes">Minor changes to the library</h3>
 
 <dl id="reflect"><dt><a href="/pkg/reflect/">reflect</a></dt>
   <dd>
+    <p><!-- CL 334669 -->
+      The new
+      <a href="/pkg/reflect/#Value.CanConvert"><code>Value.CanConvert</code></a>
+      method reports whether a value can be converted to a type.
+      This may be used to avoid a panic when converting a slice to an
+      array pointer type if the slice is too short.
+      Previously it was sufficient to use
+      <a href="/pkg/reflect/#Type.ConvertibleTo"><code>Type.ConvertibleTo</code></a>
+      for this, but the newly permitted conversion from slice to array
+      pointer type can panic even if the types are convertible.
+    </p>
+
     <p><!-- CL 266197 -->
       The new
       <a href="/pkg/reflect/#StructField.IsExported"><code>StructField.IsExported</code></a>

doc/go_spec.html

@@ -1,6 +1,6 @@
 <!--{
 	"Title": "The Go Programming Language Specification",
-	"Subtitle": "Version of Jul 1, 2021",
+	"Subtitle": "Version of Jul 26, 2021",
 	"Path": "/ref/spec"
 }-->
 
@@ -490,8 +490,8 @@ <h3 id="Rune_literals">Rune literals</h3>
 \n   U+000A line feed or newline
 \r   U+000D carriage return
 \t   U+0009 horizontal tab
-\v   U+000b vertical tab
-\\   U+005c backslash
+\v   U+000B vertical tab
+\\   U+005C backslash
 \'   U+0027 single quote  (valid escape only within rune literals)
 \"   U+0022 double quote  (valid escape only within string literals)
 </pre>
@@ -4334,7 +4334,10 @@ <h4 id="Conversions_from_slice_to_array_pointer">Conversions from slice to array
 
 var t []string
 t0 := (*[0]string)(t)    // t0 == nil
-t1 := (*[1]string)(t)    // panics: len([1]string) > len(s)
+t1 := (*[1]string)(t)    // panics: len([1]string) > len(t)
+
+u := make([]byte, 0)
+u0 = (*[0]byte)(u)       // u0 != nil
 </pre>
 
 <h3 id="Constant_expressions">Constant expressions</h3>

src/cmd/compile/internal/abi/abiutils.go

@@ -446,35 +446,20 @@ func (config *ABIConfig) ABIAnalyze(t *types.Type, setNname bool) *ABIParamResul
 	return result
 }
 
-// parameterUpdateMu protects the Offset field of function/method parameters (a subset of structure Fields)
-var parameterUpdateMu sync.Mutex
-
-// FieldOffsetOf returns a concurrency-safe version of f.Offset
-func FieldOffsetOf(f *types.Field) int64 {
-	parameterUpdateMu.Lock()
-	defer parameterUpdateMu.Unlock()
-	return f.Offset
-}
-
 func (config *ABIConfig) updateOffset(result *ABIParamResultInfo, f *types.Field, a ABIParamAssignment, isReturn, setNname bool) {
 	// Everything except return values in registers has either a frame home (if not in a register) or a frame spill location.
 	if !isReturn || len(a.Registers) == 0 {
 		// The type frame offset DOES NOT show effects of minimum frame size.
 		// Getting this wrong breaks stackmaps, see liveness/plive.go:WriteFuncMap and typebits/typebits.go:Set
-		parameterUpdateMu.Lock()
-		defer parameterUpdateMu.Unlock()
 		off := a.FrameOffset(result)
 		fOffset := f.Offset
 		if fOffset == types.BOGUS_FUNARG_OFFSET {
-			// Set the Offset the first time. After that, we may recompute it, but it should never change.
-			f.Offset = off
-			if f.Nname != nil {
-				// always set it in this case.
+			if setNname && f.Nname != nil {
 				f.Nname.(*ir.Name).SetFrameOffset(off)
 				f.Nname.(*ir.Name).SetIsOutputParamInRegisters(false)
 			}
-		} else if fOffset != off {
-			base.Fatalf("offset for %s at %s changed from %d to %d", f.Sym.Name, base.FmtPos(f.Pos), fOffset, off)
+		} else {
+			base.Fatalf("field offset for %s at %s has been set to %d", f.Sym.Name, base.FmtPos(f.Pos), fOffset)
 		}
 	} else {
 		if setNname && f.Nname != nil {

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

@@ -148,7 +148,7 @@ func dumpdata() {
 	if reflectdata.ZeroSize > 0 {
 		zero := base.PkgLinksym("go.map", "zero", obj.ABI0)
 		objw.Global(zero, int32(reflectdata.ZeroSize), obj.DUPOK|obj.RODATA)
-		zero.Set(obj.AttrContentAddressable, true)
+		zero.Set(obj.AttrStatic, true)
 	}
 
 	staticdata.WriteFuncSyms()

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

@@ -1296,7 +1296,7 @@ func (s *state) instrumentFields(t *types.Type, addr *ssa.Value, kind instrument
 		if f.Sym.IsBlank() {
 			continue
 		}
-		offptr := s.newValue1I(ssa.OpOffPtr, types.NewPtr(f.Type), abi.FieldOffsetOf(f), addr)
+		offptr := s.newValue1I(ssa.OpOffPtr, types.NewPtr(f.Type), f.Offset, addr)
 		s.instrumentFields(f.Type, offptr, kind)
 	}
 }
@@ -5053,19 +5053,23 @@ func (s *state) call(n *ir.CallExpr, k callKind, returnResultAddr bool) *ssa.Val
 		ft := fn.Type()
 		off := t.FieldOff(12) // TODO register args: be sure this isn't a hardcoded param stack offset.
 		args := n.Args
+		i0 := 0
 
 		// Set receiver (for interface calls). Always a pointer.
 		if rcvr != nil {
 			p := s.newValue1I(ssa.OpOffPtr, ft.Recv().Type.PtrTo(), off, addr)
 			s.store(types.Types[types.TUINTPTR], p, rcvr)
+			i0 = 1
 		}
 		// Set receiver (for method calls).
 		if n.Op() == ir.OCALLMETH {
 			base.Fatalf("OCALLMETH missed by walkCall")
 		}
 		// Set other args.
-		for _, f := range ft.Params().Fields().Slice() {
-			s.storeArgWithBase(args[0], f.Type, addr, off+abi.FieldOffsetOf(f))
+		// This code is only used when RegabiDefer is not enabled, and arguments are always
+		// passed on stack.
+		for i, f := range ft.Params().Fields().Slice() {
+			s.storeArgWithBase(args[0], f.Type, addr, off+params.InParam(i+i0).FrameOffset(params))
 			args = args[1:]
 		}
 
@@ -5078,7 +5082,6 @@ func (s *state) call(n *ir.CallExpr, k callKind, returnResultAddr bool) *ssa.Val
 		if stksize < int64(types.PtrSize) {
 			// We need room for both the call to deferprocStack and the call to
 			// the deferred function.
-			// TODO(register args) Revisit this if/when we pass args in registers.
 			stksize = int64(types.PtrSize)
 		}
 		call.AuxInt = stksize
@@ -6598,6 +6601,7 @@ func EmitArgInfo(f *ir.Func, abiInfo *abi.ABIParamResultInfo) *obj.LSym {
 	x := base.Ctxt.Lookup(fmt.Sprintf("%s.arginfo%d", f.LSym.Name, f.ABI))
 
 	PtrSize := int64(types.PtrSize)
+	uintptrTyp := types.Types[types.TUINTPTR]
 
 	isAggregate := func(t *types.Type) bool {
 		return t.IsStruct() || t.IsArray() || t.IsComplex() || t.IsInterface() || t.IsString() || t.IsSlice()
@@ -6641,31 +6645,28 @@ func EmitArgInfo(f *ir.Func, abiInfo *abi.ABIParamResultInfo) *obj.LSym {
 	n := 0
 	writebyte := func(o uint8) { wOff = objw.Uint8(x, wOff, o) }
 
-	// Write one non-aggrgate arg/field/element if there is room.
-	// Returns whether to continue.
-	write1 := func(sz, offset int64) bool {
-		if n >= limit {
-			return false
-		}
+	// Write one non-aggrgate arg/field/element.
+	write1 := func(sz, offset int64) {
 		if offset >= _special {
 			writebyte(_offsetTooLarge)
 		} else {
 			writebyte(uint8(offset))
 			writebyte(uint8(sz))
 		}
 		n++
-		return true
 	}
 
 	// Visit t recursively and write it out.
 	// Returns whether to continue visiting.
 	var visitType func(baseOffset int64, t *types.Type, depth int) bool
 	visitType = func(baseOffset int64, t *types.Type, depth int) bool {
 		if n >= limit {
+			writebyte(_dotdotdot)
 			return false
 		}
 		if !isAggregate(t) {
-			return write1(t.Size(), baseOffset)
+			write1(t.Size(), baseOffset)
+			return true
 		}
 		writebyte(_startAgg)
 		depth++
@@ -6675,58 +6676,47 @@ func EmitArgInfo(f *ir.Func, abiInfo *abi.ABIParamResultInfo) *obj.LSym {
 			n++
 			return true
 		}
-		var r bool
 		switch {
 		case t.IsInterface(), t.IsString():
-			r = write1(PtrSize, baseOffset) &&
-				write1(PtrSize, baseOffset+PtrSize)
+			_ = visitType(baseOffset, uintptrTyp, depth) &&
+				visitType(baseOffset+PtrSize, uintptrTyp, depth)
 		case t.IsSlice():
-			r = write1(PtrSize, baseOffset) &&
-				write1(PtrSize, baseOffset+PtrSize) &&
-				write1(PtrSize, baseOffset+PtrSize*2)
+			_ = visitType(baseOffset, uintptrTyp, depth) &&
+				visitType(baseOffset+PtrSize, uintptrTyp, depth) &&
+				visitType(baseOffset+PtrSize*2, uintptrTyp, depth)
 		case t.IsComplex():
-			r = write1(t.Size()/2, baseOffset) &&
-				write1(t.Size()/2, baseOffset+t.Size()/2)
+			_ = visitType(baseOffset, types.FloatForComplex(t), depth) &&
+				visitType(baseOffset+t.Size()/2, types.FloatForComplex(t), depth)
 		case t.IsArray():
-			r = true
 			if t.NumElem() == 0 {
 				n++ // {} counts as a component
 				break
 			}
 			for i := int64(0); i < t.NumElem(); i++ {
 				if !visitType(baseOffset, t.Elem(), depth) {
-					r = false
 					break
 				}
 				baseOffset += t.Elem().Size()
 			}
 		case t.IsStruct():
-			r = true
 			if t.NumFields() == 0 {
 				n++ // {} counts as a component
 				break
 			}
 			for _, field := range t.Fields().Slice() {
 				if !visitType(baseOffset+field.Offset, field.Type, depth) {
-					r = false
 					break
 				}
 			}
 		}
-		if !r {
-			writebyte(_dotdotdot)
-		}
 		writebyte(_endAgg)
-		return r
+		return true
 	}
 
-	c := true
 	for _, a := range abiInfo.InParams() {
-		if !c {
-			writebyte(_dotdotdot)
+		if !visitType(a.FrameOffset(abiInfo), a.Type, 0) {
 			break
 		}
-		c = visitType(a.FrameOffset(abiInfo), a.Type, 0)
 	}
 	writebyte(_endSeq)
 	if wOff > maxLen {

src/cmd/compile/internal/typecheck/dcl.go

@@ -106,7 +106,17 @@ func Export(n *ir.Name) {
 // Redeclared emits a diagnostic about symbol s being redeclared at pos.
 func Redeclared(pos src.XPos, s *types.Sym, where string) {
 	if !s.Lastlineno.IsKnown() {
-		pkgName := DotImportRefs[s.Def.(*ir.Ident)]
+		var pkgName *ir.PkgName
+		if s.Def == nil {
+			for id, pkg := range DotImportRefs {
+				if id.Sym().Name == s.Name {
+					pkgName = pkg
+					break
+				}
+			}
+		} else {
+			pkgName = DotImportRefs[s.Def.(*ir.Ident)]
+		}
 		base.ErrorfAt(pos, "%v redeclared %s\n"+
 			"\t%v: previous declaration during import %q", s, where, base.FmtPos(pkgName.Pos()), pkgName.Pkg.Path)
 	} else {

src/cmd/compile/internal/typecheck/iimport.go

@@ -1540,7 +1540,7 @@ func (r *importReader) exprsOrNil() (a, b ir.Node) {
 func builtinCall(pos src.XPos, op ir.Op) *ir.CallExpr {
 	if go117ExportTypes {
 		// These should all be encoded as direct ops, not OCALL.
-		base.Fatalf("builtinCall should not be invoked when types are included in inport/export")
+		base.Fatalf("builtinCall should not be invoked when types are included in import/export")
 	}
 	return ir.NewCallExpr(pos, ir.OCALL, ir.NewIdent(base.Pos, types.BuiltinPkg.Lookup(ir.OpNames[op])), nil)
 }

src/cmd/go/alldocs.go

@@ -2848,3 +2848,35 @@ func TestExecInDeletedDir(t *testing.T) {
 	// `go version` should not fail
 	tg.run("version")
 }
+
+// A missing C compiler should not force the net package to be stale.
+// Issue 47215.
+func TestMissingCC(t *testing.T) {
+	if !canCgo {
+		t.Skip("test is only meaningful on systems with cgo")
+	}
+	cc := os.Getenv("CC")
+	if cc == "" {
+		cc = "gcc"
+	}
+	if filepath.IsAbs(cc) {
+		t.Skipf(`"CC" (%s) is an absolute path`, cc)
+	}
+	_, err := exec.LookPath(cc)
+	if err != nil {
+		t.Skipf(`"CC" (%s) not on PATH`, cc)
+	}
+
+	tg := testgo(t)
+	defer tg.cleanup()
+	netStale, _ := tg.isStale("net")
+	if netStale {
+		t.Skip(`skipping test because "net" package is currently stale`)
+	}
+
+	tg.setenv("PATH", "") // No C compiler on PATH.
+	netStale, _ = tg.isStale("net")
+	if netStale {
+		t.Error(`clearing "PATH" causes "net" to be stale`)
+	}
+}

src/cmd/go/go_test.go

@@ -25,7 +25,7 @@ import (
 )
 
 var cmdEdit = &base.Command{
-	UsageLine: "go mod edit [editing flags] [go.mod]",
+	UsageLine: "go mod edit [editing flags] [-fmt|-print|-json] [go.mod]",
 	Short:     "edit go.mod from tools or scripts",
 	Long: `
 Edit provides a command-line interface for editing go.mod,

src/cmd/go/internal/modcmd/edit.go

@@ -26,7 +26,7 @@ in text form. Each line in the output has two space-separated fields: a module
 and one of its requirements. Each module is identified as a string of the form
 path@version, except for the main module, which has no @version suffix.
 
-The -go flag causes graph to report the module graph as loaded by by the
+The -go flag causes graph to report the module graph as loaded by the
 given Go version, instead of the version indicated by the 'go' directive
 in the go.mod file.