runtime: implement pthread functions for darwin/arm64

They were not needed when Go only produced binaries with cgo suppport.
Now that Go is about to run self-hosted on iOS we do need these.

Updates #31722

Change-Id: If233aa2b31edc7b1c2dcac68974f9fba0604f9a3
Reviewed-on: https://go-review.googlesource.com/c/go/+/174300
Run-TryBot: Elias Naur <mail@eliasnaur.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

diff --git a/src/runtime/sys_darwin_arm64.s b/src/runtime/sys_darwin_arm64.s
index 89a2b8a054412356b2f1f580d8d82988f1a964f5..fa6157eba906ddaacb6f9a716f41f45aa8fac57c 100644 (file)
--- a/src/runtime/sys_darwin_arm64.s
+++ b/src/runtime/sys_darwin_arm64.s
@@ -304,33 +304,92 @@ TEXT runtime·sigaltstack_trampoline(SB),NOSPLIT,$0
        RET
 
 // Thread related functions
-// Note: On darwin/arm64, the runtime always use runtime/cgo to
-// create threads, so all thread related functions will just exit with a
-// unique status.
 
+// mstart_stub is the first function executed on a new thread started by pthread_create.
+// It just does some low-level setup and then calls mstart.
+// Note: called with the C calling convention.
 TEXT runtime·mstart_stub(SB),NOSPLIT,$0
-       MOVW    $44, R0
-       BL      libc_exit(SB)
+       // R0 points to the m.
+       // We are already on m's g0 stack.
+
+       // Save callee-save registers.
+       SUB $144, RSP
+       MOVD R19, 0(RSP)
+       MOVD R20, 8(RSP)
+       MOVD R21, 16(RSP)
+       MOVD R22, 24(RSP)
+       MOVD R23, 32(RSP)
+       MOVD R24, 40(RSP)
+       MOVD R25, 48(RSP)
+       MOVD R26, 56(RSP)
+       MOVD R27, 64(RSP)
+       MOVD g, 72(RSP)
+       FMOVD F8, 80(RSP)
+       FMOVD F9, 88(RSP)
+       FMOVD F10, 96(RSP)
+       FMOVD F11, 104(RSP)
+       FMOVD F12, 112(RSP)
+       FMOVD F13, 120(RSP)
+       FMOVD F14, 128(RSP)
+       FMOVD F15, 136(RSP)
+
+       MOVD    m_g0(R0), g
+
+       BL runtime·mstart(SB)
+
+       // Restore callee-save registers.
+       MOVD 0(RSP), R19
+       MOVD 8(RSP), R20
+       MOVD 16(RSP), R21
+       MOVD 24(RSP), R22
+       MOVD 32(RSP), R23
+       MOVD 40(RSP), R24
+       MOVD 48(RSP), R25
+       MOVD 56(RSP), R26
+       MOVD 64(RSP), R27
+       MOVD 72(RSP), g
+       FMOVD 80(RSP), F8
+       FMOVD 88(RSP), F9
+       FMOVD 96(RSP), F10
+       FMOVD 104(RSP), F11
+       FMOVD 112(RSP), F12
+       FMOVD 120(RSP), F13
+       FMOVD 128(RSP), F14
+       FMOVD 136(RSP), F15
+       ADD $144, RSP
+
+       // Go is all done with this OS thread.
+       // Tell pthread everything is ok (we never join with this thread, so
+       // the value here doesn't really matter).
+       MOVD $0, R0
+
        RET
 
 TEXT runtime·pthread_attr_init_trampoline(SB),NOSPLIT,$0
-       MOVW    $45, R0
-       BL      libc_exit(SB)
+       MOVD    0(R0), R0       // arg 1 attr
+       BL      libc_pthread_attr_init(SB)
        RET
 
 TEXT runtime·pthread_attr_setstacksize_trampoline(SB),NOSPLIT,$0
-       MOVW    $46, R0
-       BL      libc_exit(SB)
+       MOVD    8(R0), R1       // arg 2 size
+       MOVD    0(R0), R0       // arg 1 attr
+       BL      libc_pthread_attr_setstacksize(SB)
        RET
 
 TEXT runtime·pthread_attr_setdetachstate_trampoline(SB),NOSPLIT,$0
-       MOVW    $47, R0
-       BL      libc_exit(SB)
+       MOVD    8(R0), R1       // arg 2 state
+       MOVD    0(R0), R0       // arg 1 attr
+       BL      libc_pthread_attr_setdetachstate(SB)
        RET
 
 TEXT runtime·pthread_create_trampoline(SB),NOSPLIT,$0
-       MOVW    $48, R0
-       BL      libc_exit(SB)
+       SUB     $16, RSP
+       MOVD    0(R0), R1       // arg 2 state
+       MOVD    8(R0), R2       // arg 3 start
+       MOVD    16(R0), R3      // arg 4 arg
+       MOVD    RSP, R0         // arg 1 &threadid (which we throw away)
+       BL      libc_pthread_create(SB)
+       ADD     $16, RSP
        RET
 
 TEXT runtime·raise_trampoline(SB),NOSPLIT,$0