runtime: implement darwin raise with pthread_self and pthread_kill

Convert raise from raw syscalls to using the system pthread library.
As a bonus, raise will now target the current thread instead of the
process.

Updates #17490

Change-Id: I2e44f2000bf870e99a5b4dc5ff5e0799fba91bde
Reviewed-on: https://go-review.googlesource.com/110475
Run-TryBot: Elias Naur <elias.naur@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

src/runtime/os_darwin.go

@@ -540,7 +540,12 @@ func sigtramp(fn uintptr, infostyle, sig uint32, info *siginfo, ctx unsafe.Point
 //go:noescape
 func setitimer(mode int32, new, old *itimerval)
 
-func raise(sig uint32)
+//go:nosplit
+func raise(sig uint32) {
+	tid := pthread_self()
+	pthread_kill(tid, int(sig))
+}
+
 func raiseproc(sig uint32)
 
 //extern SigTabTT runtime·sigtab[];

src/runtime/sys_darwin.go

@@ -53,6 +53,28 @@ func pthread_create(attr *pthreadattr, start uintptr, arg unsafe.Pointer) (t pth
 //go:noescape
 func pthread_create_trampoline(t *pthread, attr *pthreadattr, start uintptr, arg unsafe.Pointer) int32
 
+//go:nowritebarrier
+func pthread_kill(thread pthread, sig int) (errno int32) {
+	systemstack(func() {
+		errno = pthread_kill_trampoline(thread, sig)
+	})
+	return
+}
+
+//go:noescape
+func pthread_kill_trampoline(thread pthread, sig int) int32
+
+//go:nowritebarrier
+func pthread_self() (t pthread) {
+	systemstack(func() {
+		t = pthread_self_trampoline()
+	})
+	return
+}
+
+//go:noescape
+func pthread_self_trampoline() pthread
+
 // Tell the linker that the libc_* functions are to be found
 // in a system library, with the libc_ prefix missing.
 
@@ -61,6 +83,8 @@ func pthread_create_trampoline(t *pthread, attr *pthreadattr, start uintptr, arg
 //go:cgo_import_dynamic libc_pthread_attr_setdetachstate pthread_attr_setdetachstate "/usr/lib/libSystem.B.dylib"
 //go:cgo_import_dynamic libc_pthread_create pthread_create "/usr/lib/libSystem.B.dylib"
 //go:cgo_import_dynamic libc_exit exit "/usr/lib/libSystem.B.dylib"
+//go:cgo_import_dynamic libc_pthread_kill pthread_kill "/usr/lib/libSystem.B.dylib"
+//go:cgo_import_dynamic libc_pthread_self pthread_self "/usr/lib/libSystem.B.dylib"
 
 // Magic incantation to get libSystem actually dynamically linked.
 // TODO: Why does the code require this?  See cmd/compile/internal/ld/go.go:210

src/runtime/sys_darwin_386.s

@@ -61,11 +61,6 @@ TEXT runtime·write(SB),NOSPLIT,$0
 	MOVL	AX, ret+12(FP)
 	RET
 
-TEXT runtime·raise(SB),NOSPLIT,$0
-	// Ideally we'd send the signal to the current thread,
-	// not the whole process, but that's too hard on OS X.
-	JMP	runtime·raiseproc(SB)
-
 TEXT runtime·raiseproc(SB),NOSPLIT,$16
 	MOVL	$20, AX // getpid
 	INT	$0x80
@@ -575,3 +570,36 @@ TEXT runtime·pthread_create_trampoline(SB),NOSPLIT,$0-20
 
 	MOVL	AX, ret+16(FP)
 	RET
+
+TEXT runtime·pthread_self_trampoline(SB),NOSPLIT,$0-4
+	PUSHL   BP
+	MOVL    SP, BP
+
+	ANDL	$~15, SP
+
+	CALL    libc_pthread_self(SB)
+
+	MOVL    BP, SP
+	POPL    BP
+
+	MOVL    AX, ret+0(FP)
+	RET
+
+TEXT runtime·pthread_kill_trampoline(SB),NOSPLIT,$0-12
+	MOVL    thread+0(FP), AX
+	MOVL    sig+4(FP), CX
+	PUSHL   BP
+	MOVL    SP, BP
+
+	SUBL	$8, SP
+	ANDL	$~15, SP
+
+	MOVL	AX, 0(SP)
+	MOVL	CX, 4(SP)
+	CALL    libc_pthread_kill(SB)
+
+	MOVL    BP, SP
+	POPL    BP
+
+	MOVL    AX, ret+8(FP)
+	RET

src/runtime/sys_darwin_amd64.s

@@ -74,11 +74,6 @@ TEXT runtime·write(SB),NOSPLIT,$0
 	MOVL	AX, ret+24(FP)
 	RET
 
-TEXT runtime·raise(SB),NOSPLIT,$0
-	// Ideally we'd send the signal to the current thread,
-	// not the whole process, but that's too hard on OS X.
-	JMP	runtime·raiseproc(SB)
-
 TEXT runtime·raiseproc(SB),NOSPLIT,$24
 	MOVL	$(0x2000000+20), AX // getpid
 	SYSCALL
@@ -607,3 +602,25 @@ TEXT runtime·pthread_create_trampoline(SB),NOSPLIT,$0-36
 	POPQ	BP
 	MOVL	AX, ret+32(FP)
 	RET
+
+TEXT runtime·pthread_self_trampoline(SB),NOSPLIT,$0-8
+	PUSHQ	BP
+	MOVQ	SP, BP
+	ANDQ	$~15, SP
+	CALL	libc_pthread_self(SB)
+	MOVQ	BP, SP
+	POPQ	BP
+	MOVQ	AX, ret+0(FP)
+	RET
+
+TEXT runtime·pthread_kill_trampoline(SB),NOSPLIT,$0-20
+	MOVQ	thread+0(FP), DI
+	MOVQ	sig+8(FP), SI
+	PUSHQ	BP
+	MOVQ	SP, BP
+	ANDQ	$~15, SP
+	CALL	libc_pthread_kill(SB)
+	MOVQ	BP, SP
+	POPQ	BP
+	MOVL	AX, ret+16(FP)
+	RET