Revert "runtime/cgo: store M for C-created thread in pthread key"

This reverts CL 392854.

Reason for revert: caused #59294, which was derived from google
internal tests. The attempted fix of #59294 caused more breakage.

Change-Id: I5a061561ac2740856b7ecc09725ac28bd30f8bba
Reviewed-on: https://go-review.googlesource.com/c/go/+/481060
Reviewed-by: Heschi Kreinick <heschi@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

4 files changed, 3 insertions, 64 deletions

diff --git a/misc/cgo/test/cgo_test.go b/misc/cgo/test/cgo_test.go
index 0c3980c12d..5b298954f5 100644
--- a/misc/cgo/test/cgo_test.go
+++ b/misc/cgo/test/cgo_test.go
@@ -104,7 +104,6 @@ func TestThreadLock(t *testing.T)            { testThreadLockFunc(t) }
 func TestUnsignedInt(t *testing.T)           { testUnsignedInt(t) }
 func TestZeroArgCallback(t *testing.T)       { testZeroArgCallback(t) }
 
-func BenchmarkCgoCall(b *testing.B)      { benchCgoCall(b) }
-func BenchmarkGoString(b *testing.B)     { benchGoString(b) }
-func BenchmarkCGoCallback(b *testing.B)  { benchCallback(b) }
-func BenchmarkCGoInCThread(b *testing.B) { benchCGoInCthread(b) }
+func BenchmarkCgoCall(b *testing.B)     { benchCgoCall(b) }
+func BenchmarkGoString(b *testing.B)    { benchGoString(b) }
+func BenchmarkCGoCallback(b *testing.B) { benchCallback(b) }
diff --git a/misc/cgo/test/cthread_unix.c b/misc/cgo/test/cthread_unix.c
index 13623254a9..247d636d06 100644
--- a/misc/cgo/test/cthread_unix.c
+++ b/misc/cgo/test/cthread_unix.c
@@ -32,27 +32,3 @@ doAdd(int max, int nthread)
 	for(i=0; i<nthread; i++)
 		pthread_join(thread_id[i], 0);		
 }
-
-static void*
-goDummyCallbackThread(void* p)
-{
-	int i, max;
-
-	max = *(int*)p;
-	for(i=0; i<max; i++)
-		goDummy();
-	return NULL;
-}
-
-int
-callGoInCThread(int max)
-{
-	pthread_t thread;
-
-	if (pthread_create(&thread, NULL, goDummyCallbackThread, (void*)(&max)) != 0)
-		return -1;
-	if (pthread_join(thread, NULL) != 0)
-		return -1;
-
-	return max;
-}
diff --git a/misc/cgo/test/cthread_windows.c b/misc/cgo/test/cthread_windows.c
index 4e52209dee..3a62ddd373 100644
--- a/misc/cgo/test/cthread_windows.c
+++ b/misc/cgo/test/cthread_windows.c
@@ -35,25 +35,3 @@ doAdd(int max, int nthread)
 		CloseHandle((HANDLE)thread_id[i]);
 	}
 }
-
-__stdcall
-static unsigned int
-goDummyCallbackThread(void* p)
-{
-	int i, max;
-
-	max = *(int*)p;
-	for(i=0; i<max; i++)
-		goDummy();
-	return 0;
-}
-
-int
-callGoInCThread(int max)
-{
-	uintptr_t thread_id;
-	thread_id = _beginthreadex(0, 0, goDummyCallbackThread, &max, 0, 0);
-	WaitForSingleObject((HANDLE)thread_id, INFINITE);
-	CloseHandle((HANDLE)thread_id);
-	return max;
-}
diff --git a/misc/cgo/test/testx.go b/misc/cgo/test/testx.go
index 0e2a51a522..6a8e97ddf3 100644
--- a/misc/cgo/test/testx.go
+++ b/misc/cgo/test/testx.go
@@ -24,7 +24,6 @@ import (
 /*
 // threads
 extern void doAdd(int, int);
-extern int callGoInCThread(int);
 
 // issue 1328
 void IntoC(void);
@@ -147,10 +146,6 @@ func Add(x int) {
 	*p = 2
 }
 
-//export goDummy
-func goDummy() {
-}
-
 func testCthread(t *testing.T) {
 	if (runtime.GOOS == "darwin" || runtime.GOOS == "ios") && runtime.GOARCH == "arm64" {
 		t.Skip("the iOS exec wrapper is unable to properly handle the panic from Add")
@@ -164,15 +159,6 @@ func testCthread(t *testing.T) {
 	}
 }
 
-// Benchmark measuring overhead from C to Go in a C thread.
-// Create a new C thread and invoke Go function repeatedly in the new C thread.
-func benchCGoInCthread(b *testing.B) {
-	n := C.callGoInCThread(C.int(b.N))
-	if int(n) != b.N {
-		b.Fatal("unmatch loop times")
-	}
-}
-
 // issue 1328
 
 //export BackIntoGo