[dev.typeparams] all: merge master (46fd547) into dev.typeparams

Conflicts:

- src/go/types/check_test.go

  CL 324730 on dev.typeparams changed the directory paths in TestCheck,
  TestExamples, and TestFixedbugs and renamed checkFiles to testFiles;
  whereas CL 337529 on master added a new test case just above them and
  that used checkFiles.

Merge List:

+ 2021-08-12 46fd547d89 internal/goversion: update Version to 1.18
+ 2021-08-12 5805efc78e doc/go1.17: remove draft notice
+ 2021-08-12 39634e7dae CONTRIBUTORS: update for the Go 1.17 release
+ 2021-08-12 095bb790e1 os/exec: re-enable LookPathTest/16
+ 2021-08-11 dea23e9ca8 src/make.*: make --no-clean flag a no-op that prints a warning
+ 2021-08-11 d4c0ed26ac doc/go1.17: linker passes -I to extld as -Wl,--dynamic-linker
+ 2021-08-10 1f9c9d8530 doc: use "high address/low address" instead of "top/bottom"
+ 2021-08-09 f1dce319ff cmd/go: with -mod=vendor, don't panic if there are duplicate requirements
+ 2021-08-09 7aeaad5c86 runtime/cgo: when using msan explicitly unpoison cgoCallers
+ 2021-08-08 507cc341ec doc: add example for conversion from slice expressions to array ptr
+ 2021-08-07 891547e2d4 doc/go1.17: fix a typo introduced in CL 335135
+ 2021-08-06 8eaf4d16bc make.bash: do not overwrite GO_LDSO if already set
+ 2021-08-06 63b968f4f8 doc/go1.17: clarify Modules changes
+ 2021-08-06 70546f6404 runtime: allow arm64 SEH to be called if illegal instruction
+ 2021-08-05 fd45e267c2 runtime: warn that KeepAlive is not an unsafe.Pointer workaround
+ 2021-08-04 6e738868a7 net/http: speed up and deflake TestCancelRequestWhenSharingConnection
+ 2021-08-02 8a7ee4c51e io/fs: don't use absolute path in DirEntry.Name doc
+ 2021-07-31 b8ca6e59ed all: gofmt
+ 2021-07-30 b7a85e0003 net/http/httputil: close incoming ReverseProxy request body
+ 2021-07-29 70fd4e47d7 runtime: avoid possible preemption when returning from Go to C
+ 2021-07-28 9eee0ed439 cmd/go: fix go.mod file name printed in error messages for replacements
+ 2021-07-28 b39e0f461c runtime: don't crash on nil pointers in checkptrAlignment
+ 2021-07-27 7cd10c1149 cmd/go: use .mod instead of .zip to determine if version has go.mod file
+ 2021-07-27 c8cf0f74e4 cmd/go: add missing flag in UsageLine
+ 2021-07-27 7ba8e796c9 testing: clarify T.Name returns a distinct name of the running test
+ 2021-07-27 33ff155970 go/types: preserve untyped constants on the RHS of a shift expression
+ 2021-07-26 840e583ff3 runtime: correct variable name in comment
+ 2021-07-26 bfbb288574 runtime: remove adjustTimers counter
+ 2021-07-26 9c81fd53b3 cmd/vet: add missing copyright header

Change-Id: Ia80604d24c6f4205265683024e3100769cf32065

2 files changed, 110 insertions, 0 deletions

diff --git a/misc/cgo/testsanitizers/msan_test.go b/misc/cgo/testsanitizers/msan_test.go
index 2a3494fbfc..5ee9947a58 100644
--- a/misc/cgo/testsanitizers/msan_test.go
+++ b/misc/cgo/testsanitizers/msan_test.go
@@ -42,6 +42,7 @@ func TestMSAN(t *testing.T) {
 		{src: "msan5.go"},
 		{src: "msan6.go"},
 		{src: "msan7.go"},
+		{src: "msan8.go"},
 		{src: "msan_fail.go", wantErr: true},
 	}
 	for _, tc := range cases {
diff --git a/misc/cgo/testsanitizers/testdata/msan8.go b/misc/cgo/testsanitizers/testdata/msan8.go
new file mode 100644
index 0000000000..1cb5c5677f
--- /dev/null
+++ b/misc/cgo/testsanitizers/testdata/msan8.go
@@ -0,0 +1,109 @@
+// Copyright 2021 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
+
+/*
+#include <pthread.h>
+#include <signal.h>
+#include <stdint.h>
+
+#include <sanitizer/msan_interface.h>
+
+// cgoTracebackArg is the type of the argument passed to msanGoTraceback.
+struct cgoTracebackArg {
+	uintptr_t context;
+	uintptr_t sigContext;
+	uintptr_t* buf;
+	uintptr_t max;
+};
+
+// msanGoTraceback is registered as the cgo traceback function.
+// This will be called when a signal occurs.
+void msanGoTraceback(void* parg) {
+	struct cgoTracebackArg* arg = (struct cgoTracebackArg*)(parg);
+        arg->buf[0] = 0;
+}
+
+// msanGoWait will be called with all registers undefined as far as
+// msan is concerned. It just waits for a signal.
+// Because the registers are msan-undefined, the signal handler will
+// be invoked with all registers msan-undefined.
+__attribute__((noinline))
+void msanGoWait(unsigned long a1, unsigned long a2, unsigned long a3, unsigned long a4, unsigned long a5, unsigned long a6) {
+	sigset_t mask;
+
+	sigemptyset(&mask);
+        sigsuspend(&mask);
+}
+
+// msanGoSignalThread is the thread ID of the msanGoLoop thread.
+static pthread_t msanGoSignalThread;
+
+// msanGoSignalThreadSet is used to record that msanGoSignalThread
+// has been initialized. This is accessed atomically.
+static int32_t msanGoSignalThreadSet;
+
+// uninit is explicitly poisoned, so that we can make all registers
+// undefined by calling msanGoWait.
+static unsigned long uninit;
+
+// msanGoLoop loops calling msanGoWait, with the arguments passed
+// such that msan thinks that they are undefined. msan permits
+// undefined values to be used as long as they are not used to
+// for conditionals or for memory access.
+void msanGoLoop() {
+	int i;
+
+	msanGoSignalThread = pthread_self();
+        __atomic_store_n(&msanGoSignalThreadSet, 1, __ATOMIC_SEQ_CST);
+
+	// Force uninit to be undefined for msan.
+	__msan_poison(&uninit, sizeof uninit);
+	for (i = 0; i < 100; i++) {
+		msanGoWait(uninit, uninit, uninit, uninit, uninit, uninit);
+        }
+}
+
+// msanGoReady returns whether msanGoSignalThread is set.
+int msanGoReady() {
+	return __atomic_load_n(&msanGoSignalThreadSet, __ATOMIC_SEQ_CST) != 0;
+}
+
+// msanGoSendSignal sends a signal to the msanGoLoop thread.
+void msanGoSendSignal() {
+	pthread_kill(msanGoSignalThread, SIGWINCH);
+}
+*/
+import "C"
+
+import (
+	"runtime"
+	"time"
+)
+
+func main() {
+	runtime.SetCgoTraceback(0, C.msanGoTraceback, nil, nil)
+
+	c := make(chan bool)
+	go func() {
+		defer func() { c <- true }()
+		C.msanGoLoop()
+	}()
+
+	for C.msanGoReady() == 0 {
+		time.Sleep(time.Microsecond)
+	}
+
+loop:
+	for {
+		select {
+		case <-c:
+			break loop
+		default:
+			C.msanGoSendSignal()
+			time.Sleep(time.Microsecond)
+		}
+	}
+}