1 files changed, 14 insertions, 5 deletions

diff --git a/src/buildvm_arm.dasc b/src/buildvm_arm.dasc
index 2ad02b74..e977f844 100644
--- a/src/buildvm_arm.dasc
+++ b/src/buildvm_arm.dasc
@@ -411,7 +411,7 @@ static void build_subroutines(BuildCtx *ctx)
   |
   |->vm_call_dispatch_f:
   |  ins_call
-  |  // BASE = new base, RC = nargs*8
+  |  // BASE = new base, CARG3 = func, RC = nargs*8, PC = caller PC
   |
   |->vm_cpcall:                         // Setup protected C frame, call C.
   |  // (lua_State *L, lua_CFunction func, void *ud, lua_CPFunction cp)
@@ -445,18 +445,26 @@ static void build_subroutines(BuildCtx *ctx)
   |->cont_dispatch:
   |  // BASE = meta base, RA = resultptr, RC = (nresults+1)*8
   |  ldr LFUNC:CARG3, [RB, FRAME_FUNC]
+  |    ldr CARG1, [BASE, #-16]          // Get continuation.
   |   mov CARG4, BASE
   |   mov BASE, RB                      // Restore caller BASE.
+  |    cmp CARG1, #0
   |   ldr PC, [CARG4, #-12]             // Restore PC from [cont|PC].
+  |    beq >1
   |  ldr CARG3, LFUNC:CARG3->field_pc
   |    mvn INS, #~LJ_TNIL
   |    add CARG2, RA, RC
-  |   ldr CARG1, [CARG4, #-16]          // Get continuation.
   |    str INS, [CARG2, #-4]            // Ensure one valid arg.
   |  ldr KBASE, [CARG3, #PC2PROTO(k)]
   |  // BASE = base, RA = resultptr, CARG4 = meta base
   |   bx CARG1
   |
+  |1:  // Tail call from C function.
+  |  ldr CARG3, [BASE, FRAME_FUNC]
+  |   sub CARG4, CARG4, #16
+  |   sub RC, CARG4, BASE
+  |  b ->vm_call_tail
+  |
   |->cont_cat:                          // RA = resultptr, CARG4 = meta base
   |  ldr INS, [PC, #-4]
   |   sub CARG2, CARG4, #16
@@ -714,7 +722,7 @@ static void build_subroutines(BuildCtx *ctx)
   |   str PC, SAVE_PC
   |  add CARG3, RA, NARGS8:RC
   |  bl extern lj_meta_call     // (lua_State *L, TValue *func, TValue *top)
-  |  ldr LFUNC:CARG3, [BASE, FRAME_FUNC]  // Guaranteed to be a function here.
+  |  ldr LFUNC:CARG3, [RA, FRAME_FUNC]  // Guaranteed to be a function here.
   |   ldr PC, [BASE, FRAME_PC]
   |    add NARGS8:RC, NARGS8:RC, #8     // Got one more argument now.
   |  b ->BC_CALLT2_Z
@@ -1514,10 +1522,11 @@ static void build_subroutines(BuildCtx *ctx)
   |   ldr CARG1, L->top
   |    ldr LFUNC:CARG3, [BASE, FRAME_FUNC]
   |   sub NARGS8:RC, CARG1, BASE
-  |  bne >2                             // Returned -1?
+  |  bne ->vm_call_tail                 // Returned -1?
   |  ins_callt                          // Returned 0: retry fast path.
   |
-  |2:  // Reconstruct previous base for vmeta_call during tailcall.
+  |// Reconstruct previous base for vmeta_call during tailcall.
+  |->vm_call_tail:
   |  ands CARG1, PC, #FRAME_TYPE
   |   bic CARG2, PC, #FRAME_TYPEP
   |  ldreq INS, [PC, #-4]