From 68ffbd318b331b988c32ecfdeee965e9683889f4 Mon Sep 17 00:00:00 2001
From: Mike Pall <mike>
Date: Mon, 20 Sep 2021 14:36:52 +0200
Subject: FFI: Don't load PC from non-function object in FFI continuation.

Reported by Yichun Zhang. #743
---
 src/vm_arm.dasc  | 2 +-
 src/vm_mips.dasc | 2 +-
 src/vm_ppc.dasc  | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/vm_arm.dasc b/src/vm_arm.dasc
index 21d706d8..344147e8 100644
--- a/src/vm_arm.dasc
+++ b/src/vm_arm.dasc
@@ -524,13 +524,13 @@ static void build_subroutines(BuildCtx *ctx)
   |    cmp CARG1, #1
   |.endif
   |   ldr PC, [CARG4, #-12]		// Restore PC from [cont|PC].
-  |  ldr CARG3, LFUNC:CARG3->field_pc
   |    mvn INS, #~LJ_TNIL
   |    add CARG2, RA, RC
   |    str INS, [CARG2, #-4]		// Ensure one valid arg.
   |.if FFI
   |    bls >1
   |.endif
+  |  ldr CARG3, LFUNC:CARG3->field_pc
   |  ldr KBASE, [CARG3, #PC2PROTO(k)]
   |  // BASE = base, RA = resultptr, CARG4 = meta base
   |    bx CARG1
diff --git a/src/vm_mips.dasc b/src/vm_mips.dasc
index 8cb4bd3d..03a84985 100644
--- a/src/vm_mips.dasc
+++ b/src/vm_mips.dasc
@@ -603,11 +603,11 @@ static void build_subroutines(BuildCtx *ctx)
   |.endif
   |     lw PC, -16+HI(RB)		// Restore PC from [cont|PC].
   |   addu TMP2, RA, RD
-  |    lw TMP1, LFUNC:TMP1->pc
   |.if FFI
   |  bnez AT, >1
   |.endif
   |.  sw TISNIL, -8+HI(TMP2)		// Ensure one valid arg.
+  |    lw TMP1, LFUNC:TMP1->pc
   |  // BASE = base, RA = resultptr, RB = meta base
   |  jr TMP0				// Jump to continuation.
   |.  lw KBASE, PC2PROTO(k)(TMP1)
diff --git a/src/vm_ppc.dasc b/src/vm_ppc.dasc
index e2d62e00..9c1cc36f 100644
--- a/src/vm_ppc.dasc
+++ b/src/vm_ppc.dasc
@@ -819,11 +819,11 @@ static void build_subroutines(BuildCtx *ctx)
   |.endif
   |     lwz PC, -16(RB)			// Restore PC from [cont|PC].
   |   subi TMP2, RD, 8
-  |    lwz TMP1, LFUNC:TMP1->pc
   |   stwx TISNIL, RA, TMP2		// Ensure one valid arg.
   |.if FFI
   |  ble >1
   |.endif
+  |    lwz TMP1, LFUNC:TMP1->pc
   |    lwz KBASE, PC2PROTO(k)(TMP1)
   |  // BASE = base, RA = resultptr, RB = meta base
   |  mtctr TMP0
-- 
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