From 0a18b89a04aa463b308e99710edc6c205bc87070 Mon Sep 17 00:00:00 2001
From: Michael Munday <munday@ca.ibm.com>
Date: Wed, 18 Jan 2017 12:38:53 -0500
Subject: [PATCH] Implement the LUAJIT_UNWIND_EXTERNAL option.

Still need to add support for FFI.
---
 src/lj_err.c      |  3 +++
 src/vm_s390x.dasc | 43 ++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/src/lj_err.c b/src/lj_err.c
index 600e6ee6..ff94254e 100644
--- a/src/lj_err.c
+++ b/src/lj_err.c
@@ -234,6 +234,9 @@ LJ_FUNCA int lj_err_unwind_dwarf(int version, int actions,
     return _URC_FATAL_PHASE1_ERROR;
   UNUSED(uexclass);
   cf = (void *)_Unwind_GetCFA(ctx);
+#ifdef LJ_TARGET_S390X
+  cf -= 160; /* CFA points 160 bytes above r15. */
+#endif
   L = cframe_L(cf);
   if ((actions & _UA_SEARCH_PHASE)) {
 #if LJ_UNWIND_EXT
diff --git a/src/vm_s390x.dasc b/src/vm_s390x.dasc
index 358fb767..f2dd30b7 100644
--- a/src/vm_s390x.dasc
+++ b/src/vm_s390x.dasc
@@ -4160,7 +4160,48 @@ static void emit_asm_debug(BuildCtx *ctx)
 	"\t.byte 0x8f\n\t.uleb128 0x5\n"	/* offset r15 */
 	"\t.align 8\n"
 	".LEFDE0:\n\n", fcofs, CFRAME_SIZE+160);
-    /* TODO: FFI, UNWIND */
+#if !LJ_NO_UNWIND
+    fprintf(ctx->fp, "\t.section .eh_frame,\"a\",@progbits\n");
+    fprintf(ctx->fp,
+	".Lframe1:\n"
+	"\t.long .LECIE1-.LSCIE1\n"
+	".LSCIE1:\n"
+	"\t.long 0\n"
+	"\t.byte 0x1\n"
+	"\t.string \"zPR\"\n"
+	"\t.uleb128 0x1\n"
+	"\t.sleb128 -8\n"
+	"\t.byte 0xe\n"
+	"\t.uleb128 6\n"			/* augmentation length */
+	"\t.byte 0x1b\n"			/* pcrel|sdata4 */
+	"\t.long lj_err_unwind_dwarf-.\n"
+	"\t.byte 0x1b\n"			/* pcrel|sdata4 */
+	"\t.byte 0xc\n\t.uleb128 0xf\n\t.uleb128 160\n"
+	"\t.align 8\n"
+	".LECIE1:\n\n");
+    fprintf(ctx->fp,
+	".LSFDE2:\n"
+	"\t.long .LEFDE2-.LASFDE2\n"
+	".LASFDE2:\n"
+	"\t.long .LASFDE2-.Lframe1\n"
+	"\t.long .Lbegin-.\n"
+	"\t.long %d\n"
+	"\t.uleb128 0\n"			/* augmentation length */
+	"\t.byte 0xe\n\t.uleb128 %d\n"		/* def_cfa_offset */
+	"\t.byte 0x86\n\t.uleb128 0xe\n"	/* offset r6 */
+	"\t.byte 0x87\n\t.uleb128 0xd\n"	/* offset r7 */
+	"\t.byte 0x88\n\t.uleb128 0xc\n"	/* offset r8 */
+	"\t.byte 0x89\n\t.uleb128 0xb\n"	/* offset r9 */
+	"\t.byte 0x8a\n\t.uleb128 0xa\n"	/* offset r10 */
+	"\t.byte 0x8b\n\t.uleb128 0x9\n"	/* offset r11 */
+	"\t.byte 0x8c\n\t.uleb128 0x8\n"	/* offset r12 */
+	"\t.byte 0x8d\n\t.uleb128 0x7\n"	/* offset r13 */
+	"\t.byte 0x8e\n\t.uleb128 0x6\n"	/* offset r14 */
+	"\t.byte 0x8f\n\t.uleb128 0x5\n"	/* offset r15 */
+	"\t.align 8\n"
+	".LEFDE2:\n\n", fcofs, CFRAME_SIZE+160);
+#endif
+    /* TODO: FFI */
     break;
   default:  /* No other modes. */
     break;