runtime: darwin/arm64 c-archive entry point

Change-Id: Ib227aa3e14d01a0ab1ad9e53d107858e045d1c42
Reviewed-on: https://go-review.googlesource.com/8984
Reviewed-by: Ian Lance Taylor <iant@golang.org>

diff --git a/src/runtime/rt0_darwin_arm64.s b/src/runtime/rt0_darwin_arm64.s
index c728859008ffe06f223b01f63320375f595c0fad..e4e4a30f4615b77791458b495642d477afdad73b 100644 (file)
--- a/src/runtime/rt0_darwin_arm64.s
+++ b/src/runtime/rt0_darwin_arm64.s
@@ -11,6 +11,40 @@ TEXT _rt0_arm64_darwin(SB),NOSPLIT,$-8
        MOVD    $1, R16 // SYS_exit
        SVC     $0x80
 
+// When linking with -buildmode=c-archive or -buildmode=c-shared,
+// this symbol is called from a global initialization function.
+//
+// Note that all currently shipping darwin/arm64 platforms require
+// cgo and do not support c-shared.
+TEXT _rt0_arm64_darwin_lib(SB),NOSPLIT,$0
+       // R27 is REGTMP, reserved for liblink. It is used below to
+       // move R0/R1 into globals. However in the standard ARM64 calling
+       // convention, it is a callee-saved register. So we save it to a
+       // temporary register.
+       MOVD  R27, R7
+
+       MOVD  R0, _rt0_arm64_darwin_lib_argc<>(SB)
+       MOVD  R1, _rt0_arm64_darwin_lib_argv<>(SB)
+       // Create a new thread to do the runtime initialization and return.
+       MOVD  _cgo_sys_thread_create(SB), R4
+       MOVD  $_rt0_arm64_darwin_lib_go(SB), R0
+       MOVD  $0, R1
+       BL    (R4)
+
+       MOVD  R7, R27
+       RET
+
+TEXT _rt0_arm64_darwin_lib_go(SB),NOSPLIT,$0
+       MOVD  _rt0_arm64_darwin_lib_argc<>(SB), R0
+       MOVD  _rt0_arm64_darwin_lib_argv<>(SB), R1
+       MOVD  $runtime·rt0_go(SB), R4
+       B     (R4)
+
+DATA  _rt0_arm64_darwin_lib_argc<>(SB)/8, $0
+GLOBL _rt0_arm64_darwin_lib_argc<>(SB),NOPTR, $8
+DATA  _rt0_arm64_darwin_lib_argv<>(SB)/8, $0
+GLOBL _rt0_arm64_darwin_lib_argv<>(SB),NOPTR, $8
+
 TEXT main(SB),NOSPLIT,$-8
        MOVD    $runtime·rt0_go(SB), R2
        BL      (R2)