Merge go1.21.2 into tailscale.go1.21

VERSION

@@ -1,2 +1,2 @@
-go1.21.1
-time 2023-08-31T22:36:09Z
+go1.21.2
+time 2023-09-28T20:21:36Z

src/cmd/cgo/internal/testerrors/errors_test.go

@@ -111,6 +111,7 @@ func TestReportsTypeErrors(t *testing.T) {
 	for _, file := range []string{
 		"err1.go",
 		"err2.go",
+		"err5.go",
 		"issue11097a.go",
 		"issue11097b.go",
 		"issue18452.go",

src/cmd/cgo/internal/testerrors/testdata/err5.go

@@ -0,0 +1,10 @@
+// Copyright 2023 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 main
+
+//line /tmp/_cgo_.go:1
+//go:cgo_dynamic_linker "/elf/interp" // ERROR HERE: only allowed in cgo-generated code
+
+func main() {}

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

@@ -333,8 +333,14 @@ func (p *noder) pragma(pos syntax.Pos, blankLine bool, text string, old syntax.P
 // contain cgo directives, and for security reasons
 // (primarily misuse of linker flags), other files are not.
 // See golang.org/issue/23672.
+// Note that cmd/go ignores files whose names start with underscore,
+// so the only _cgo_ files we will see from cmd/go are generated by cgo.
+// It's easy to bypass this check by calling the compiler directly;
+// we only protect against uses by cmd/go.
 func isCgoGeneratedFile(pos syntax.Pos) bool {
-	return strings.HasPrefix(filepath.Base(trimFilename(pos.Base())), "_cgo_")
+	// We need the absolute file, independent of //line directives,
+	// so we call pos.Base().Pos().
+	return strings.HasPrefix(filepath.Base(trimFilename(pos.Base().Pos().Base())), "_cgo_")
 }
 
 // safeArg reports whether arg is a "safe" command-line argument,

src/cmd/compile/internal/ssa/_gen/ARM64.rules

@@ -1552,20 +1552,22 @@
 (GreaterEqualU (FlagConstant [fc])) => (MOVDconst [b2i(fc.uge())])
 
 // absorb InvertFlags into boolean values
-(Equal         (InvertFlags x)) => (Equal x)
-(NotEqual      (InvertFlags x)) => (NotEqual x)
-(LessThan      (InvertFlags x)) => (GreaterThan x)
-(LessThanU     (InvertFlags x)) => (GreaterThanU x)
-(GreaterThan   (InvertFlags x)) => (LessThan x)
-(GreaterThanU  (InvertFlags x)) => (LessThanU x)
-(LessEqual     (InvertFlags x)) => (GreaterEqual x)
-(LessEqualU    (InvertFlags x)) => (GreaterEqualU x)
-(GreaterEqual  (InvertFlags x)) => (LessEqual x)
-(GreaterEqualU (InvertFlags x)) => (LessEqualU x)
-(LessThanF     (InvertFlags x)) => (GreaterThanF x)
-(LessEqualF    (InvertFlags x)) => (GreaterEqualF x)
-(GreaterThanF  (InvertFlags x)) => (LessThanF x)
-(GreaterEqualF (InvertFlags x)) => (LessEqualF x)
+(Equal            (InvertFlags x)) => (Equal x)
+(NotEqual         (InvertFlags x)) => (NotEqual x)
+(LessThan         (InvertFlags x)) => (GreaterThan x)
+(LessThanU        (InvertFlags x)) => (GreaterThanU x)
+(GreaterThan      (InvertFlags x)) => (LessThan x)
+(GreaterThanU     (InvertFlags x)) => (LessThanU x)
+(LessEqual        (InvertFlags x)) => (GreaterEqual x)
+(LessEqualU       (InvertFlags x)) => (GreaterEqualU x)
+(GreaterEqual     (InvertFlags x)) => (LessEqual x)
+(GreaterEqualU    (InvertFlags x)) => (LessEqualU x)
+(LessThanF        (InvertFlags x)) => (GreaterThanF x)
+(LessEqualF       (InvertFlags x)) => (GreaterEqualF x)
+(GreaterThanF     (InvertFlags x)) => (LessThanF x)
+(GreaterEqualF    (InvertFlags x)) => (LessEqualF x)
+(LessThanNoov     (InvertFlags x)) => (BIC (GreaterEqualNoov <typ.Bool> x) (Equal <typ.Bool> x))
+(GreaterEqualNoov (InvertFlags x)) => (OR (LessThanNoov <typ.Bool> x) (Equal <typ.Bool> x))
 
 // Boolean-generating instructions (NOTE: NOT all boolean Values) always
 // zero upper bit of the register; no need to zero-extend

test/fixedbugs/issue62469.go

@@ -0,0 +1,15 @@
+// compile
+
+// Copyright 2023 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
+
+func sign(p1, p2, p3 point) bool {
+	return (p1.x-p3.x)*(p2.y-p3.y)-(p2.x-p3.x)*(p1.y-p3.y) < 0
+}
+
+type point struct {
+	x, y int
+}