[Help-smalltalk] [PATCH 4/6] jit: Update _gst_ip correctly when the method_prologue is left

[Holger Hans Peter Freyther]

This has been found with the DebugTools tests and the most simple
re-producer is:

  ([3+3] newProcess singleStep; suspend; suspendedContext) inspect.

The check for _gst_except_flag is triggerred in the method prologue
and the JIT returns to the interpreter loop. When the process is
switched an old _gst_ip was written to context->ipOffset. Modify the
emit_interrupt_check to take an optional ipOffset parameter that will
be stored when the interrupt check triggers. For primitives it is
not clear which ipOffset should be saved.

2013-12-23  Holger Hans Peter Freyther  <address@hidden>

        * xlat.c: Add ipOffset parameter to emit_interrupt_check.
---
 libgst/ChangeLog |  4 ++++
 libgst/xlat.c    | 24 +++++++++++++++---------
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/libgst/ChangeLog b/libgst/ChangeLog
index 4721c17..113a0c3 100644
--- a/libgst/ChangeLog
+++ b/libgst/ChangeLog
@@ -1,3 +1,7 @@
+2013-12-23  Holger Hans Peter Freyther  <address@hidden>
+
+       * xlat.c: Add ipOffset parameter to emit_interrupt_check.
+
 2014-01-09  Holger Hans Peter Freyther  <address@hidden>
 
        * prims.def: Mark VMpr_Process_singleStepWaitingOn as
diff --git a/libgst/xlat.c b/libgst/xlat.c
index 3f4a555..fbae8f7 100644
--- a/libgst/xlat.c
+++ b/libgst/xlat.c
@@ -332,7 +332,7 @@ static inline mst_Boolean emit_block_prolog (OOP blockOOP, 
gst_compiled_block bl
 static inline mst_Boolean emit_inlined_primitive (int primitive, int numArgs, 
int attr);
 static inline mst_Boolean emit_primitive (int primitive, int numArgs);
 
-static inline void emit_interrupt_check (int restartReg);
+static inline void emit_interrupt_check (int restartReg, int ipOffset);
 static inline void generate_run_time_code (void);
 static inline void translate_method (OOP methodOOP, OOP receiverClass, int 
size);
 static void emit_basic_size_in_r0 (OOP classOOP, mst_Boolean tagged, int 
objectReg);
@@ -2498,7 +2498,7 @@ emit_deferred_sends (deferred_send *ds)
 }
 
 void
-emit_interrupt_check (int restartReg)
+emit_interrupt_check (int restartReg, int ipOffset)
 {
   jit_insn *jmp, *begin;
 
@@ -2507,9 +2507,17 @@ emit_interrupt_check (int restartReg)
 
   jit_ldi_i (JIT_R2, &_gst_except_flag);
   jmp = jit_beqi_i (jit_forward (), JIT_R2, 0);
+
+  /* Save the global ip pointer */
+  if (ipOffset != -1)
+    {
+      jit_movi_ul (JIT_R2, ipOffset);
+      jit_sti_ul (&ip, JIT_R2);
+    }
+
+  /* Where to restart?*/
   if (restartReg == JIT_NOREG)
     jit_movi_p (JIT_RET, begin);
-
   else
     jit_movr_p (JIT_RET, restartReg);
 
@@ -2975,7 +2983,7 @@ emit_primitive (int primitive, int numArgs)
   if (attr & (PRIM_SUCCEED | PRIM_RELOAD_IP))
     {
       if (attr & PRIM_CHECK_INTERRUPT)
-       emit_interrupt_check (JIT_V2);
+       emit_interrupt_check (JIT_V2, -1);
 
       jit_jmpr (JIT_V2);
     }
@@ -3218,7 +3226,7 @@ emit_method_prolog (OOP methodOOP,
   emit_context_setup (header.numArgs, header.numTemps);
 
   define_ip_map_entry (0);
-  emit_interrupt_check (JIT_NOREG);
+  emit_interrupt_check (JIT_NOREG, 0);
 
   /* For simplicity, we emit user-defined methods by creating a code_tree
      for the acrual send of #valueWithReceiver:withArguments: that they do.
@@ -3326,7 +3334,7 @@ emit_block_prolog (OOP blockOOP,
   emit_context_setup (header.numArgs, header.numTemps);
 
   define_ip_map_entry (0);
-  emit_interrupt_check (JIT_NOREG);
+  emit_interrupt_check (JIT_NOREG, 0);
 
   return (false);
 }
@@ -3675,9 +3683,7 @@ translate_method (OOP methodOOP, OOP receiverClass, int 
size)
          if (!lbl_define (*this_label))
            {
              define_ip_map_entry (bp - bc);
-             jit_movi_ul (JIT_V0, bp - bc);
-             jit_sti_ul (&ip, JIT_V0);
-             emit_interrupt_check (JIT_NOREG);
+             emit_interrupt_check (JIT_NOREG, bp - bc);
            }
        }
 
-- 
1.8.5.2