Change of special return values handled by nJSVM interpreter.

diff --git a/njs/njs_function.c b/njs/njs_function.c
index dfe81863c22307e866da52018812c7b745f230e1..9c210be84500195b7191e3fb9001223c09b1bddb 100644 (file)
--- a/njs/njs_function.c
+++ b/njs/njs_function.c
@@ -229,7 +229,7 @@ njs_function_call(njs_vm_t *vm, njs_index_t retval)
     frame->prev_local = vm->scopes[NJS_SCOPE_LOCAL];
     vm->scopes[NJS_SCOPE_LOCAL] = frame->local;
 
-    return NJS_PASS;
+    return NJS_APPLIED;
 }
 
 

diff --git a/njs/njs_vm.c b/njs/njs_vm.c
index 3506018ef943c5162b1eff32bb3d7bedb3496d14..27b781cd505f286f3442ebc0c14fcbf59af810a0 100644 (file)
--- a/njs/njs_vm.c
+++ b/njs/njs_vm.c
@@ -188,11 +188,11 @@ njs_vmcode_interpreter(njs_vm_t *vm)
              * On success an operation returns size of the bytecode,
              * a jump offset or zero after the call or return operations.
              * Jumps can return a negative offset.  Compilers can generate
-             *    (ret < 0 && ret >= NJS_PASS)
+             *    (ret < 0 && ret >= NJS_PREEMPT)
              * as a single unsigned comparision.
              */
 
-            if (nxt_slow_path(ret < 0 && ret >= NJS_PASS)) {
+            if (nxt_slow_path(ret < 0 && ret >= NJS_PREEMPT)) {
                 break;
             }
 
@@ -217,7 +217,7 @@ njs_vmcode_interpreter(njs_vm_t *vm)
         case NJS_TRAP_INCDEC:
         case NJS_TRAP_PROPERTY:
 
-            ret = njs_vm_trap(vm, ret - NJS_TRAP_LAST, value1, value2);
+            ret = njs_vm_trap(vm, ret - NJS_TRAP_BASE, value1, value2);
 
             if (nxt_fast_path(ret == NXT_OK)) {
                 goto again;
@@ -243,7 +243,7 @@ njs_vmcode_interpreter(njs_vm_t *vm)
 
                 previous = frame->native.previous;
                 if (previous == NULL) {
-                    return ret;
+                    return NXT_ERROR;
                 }
 
                 vm->frame = previous;
@@ -260,7 +260,7 @@ njs_vmcode_interpreter(njs_vm_t *vm)
             }
         }
 
-        /* NXT_AGAIN, NXT_DONE */
+        /* NXT_AGAIN, NJS_STOP. */
 
         return ret;
     }
@@ -1183,7 +1183,7 @@ njs_vmcode_property_next(njs_vm_t *vm, njs_value_t *object, njs_value_t *value)
                 return ret;
             }
 
-            /* ret == NXT_DONE. */
+            /* ret == NJS_DONE. */
         }
     }
 
@@ -2229,6 +2229,7 @@ njs_vmcode_function_call(njs_vm_t *vm, njs_value_t *invld, njs_value_t *retval)
     njs_vmcode_function_call_t  *call;
 
     call = (njs_vmcode_function_call_t *) vm->current;
+    /* Update code pointer here to store it as return address in call frame. */
     vm->current += sizeof(njs_vmcode_function_call_t);
 
     if (!vm->frame->native) {
@@ -2245,12 +2246,13 @@ njs_vmcode_function_call(njs_vm_t *vm, njs_value_t *invld, njs_value_t *retval)
     ret = vm->frame->u.native(vm, &param);
     /*
      * A native method can return:
-     *    NXT_OK on method success;
-     *    NJS_PASS by Function.apply() and Function.call();
-     *    NXT_AGAIN to postpone nJSVM processing;
-     *    NXT_ERROR.
+     *   NXT_OK on method success;
+     *   NJS_APPLIED by Function.apply() and Function.call();
+     *   NXT_AGAIN to postpone nJSVM processing;
+     *   NXT_ERROR.
      *
-     * The callee arguments must be preserved for NJS_PASS and NXT_AGAIN cases.
+     * The callee arguments must be preserved
+     * for NJS_APPLIED and NXT_AGAIN cases.
      */
     if (ret == NXT_OK) {
         skip = NULL;
@@ -2283,7 +2285,8 @@ njs_vmcode_function_call(njs_vm_t *vm, njs_value_t *invld, njs_value_t *retval)
           */
         *retval = vm->retval;
 
-    } else if (ret == NJS_PASS) {
+    } else if (ret == NJS_APPLIED) {
+        /* A user-defined method has been prepared to run. */
         ret = 0;
 
     } else if (ret == NXT_AGAIN) {
@@ -2378,7 +2381,7 @@ njs_vmcode_stop(njs_vm_t *vm, njs_value_t *invld, njs_value_t *retval)
 
     vm->retval = *value;
 
-    return NXT_DONE;
+    return NJS_STOP;
 }
 
 
@@ -2626,10 +2629,9 @@ njs_primitive_value(njs_vm_t *vm, njs_value_t *value, nxt_uint_t hint)
                         param.nargs = 0;
 
                         ret = njs_function_apply(vm, &prop->value, &param);
-
                         /*
                          * njs_function_apply() can return
-                         *     NXT_OK, NJS_PASS, NXT_ERROR, NXT_AGAIN.
+                         *   NXT_OK, NJS_APPLIED, NXT_ERROR, NXT_AGAIN.
                          */
                         if (nxt_fast_path(ret == NXT_OK)) {
 
@@ -2638,10 +2640,16 @@ njs_primitive_value(njs_vm_t *vm, njs_value_t *value, nxt_uint_t hint)
                                 break;
                             }
 
+                            /* Try the second method. */
                             continue;
                         }
 
-                        if (ret == NJS_PASS) {
+                        if (ret == NJS_APPLIED) {
+                            /*
+                             * A user-defined method has been prepared to
+                             * run.  The method will return to the current
+                             * instruction and will restart it.
+                             */
                             ret = 0;
                         }
                     }

diff --git a/njs/njs_vm.h b/njs/njs_vm.h
index b2fe2298b0838dd3ee02492c757ed61be31880b0..2b00c15091ea228cedeeadab8115d70f6ba40019 100644 (file)
--- a/njs/njs_vm.h
+++ b/njs/njs_vm.h
@@ -8,14 +8,36 @@
 #define _NJS_VM_H_INCLUDED_
 
 
-#define NJS_TRAP_NUMBER    -10
-#define NJS_TRAP_NUMBERS   -11
-#define NJS_TRAP_INCDEC    -12
-#define NJS_TRAP_STRINGS   -13
-#define NJS_TRAP_PROPERTY  -14
-#define NJS_TRAP_LAST      NJS_TRAP_PROPERTY
-
-#define NJS_PASS           -20
+/*
+ * Negative return values handled by nJSVM interpreter as special events.
+ * The values must be in range from -1 to -15, because -16 is minimal jump
+ * offset on 32-bit platforms.
+ *    -1 (NJS_ERROR/NXT_ERROR):  error or exception;
+ *    -2 (NJS_AGAIN/NXT_AGAIN):  postpone nJSVM execution;
+ *    -3:                        not used;
+ *    -4 (NJS_STOP/NXT_DONE):    njs_vmcode_stop() has stopped execution,
+ *                               execution has completed successfully;
+ *    -5 ..  -9:                 traps to convert objects to primitive values;
+ *   -10 .. -15:                 not used.
+ */
+
+#define NJS_STOP                 NXT_DONE
+
+/*  Traps events. */
+#define NJS_TRAP_NUMBER          (-5)
+#define NJS_TRAP_NUMBERS         (-6)
+#define NJS_TRAP_INCDEC          (-7)
+#define NJS_TRAP_STRINGS         (-8)
+#define NJS_TRAP_PROPERTY        (-9)
+#define NJS_TRAP_BASE            NJS_TRAP_PROPERTY
+
+#define NJS_PREEMPT              (-15)
+
+/*
+ * A user-defined function is prepared to run.  This code is never
+ * returned to interpreter, so the value can be shared with NJS_STOP.
+ */
+#define NJS_APPLIED              NXT_DONE
 
 
 /* The order of the enum is used in njs_vmcode_typeof() */

diff --git a/njs/njscript.c b/njs/njscript.c
index 9825dd6e11076c65ab505af3780b56164af6bbe2..f57956e8f166aae69f4b6489b67135a959169f08 100644 (file)
--- a/njs/njscript.c
+++ b/njs/njscript.c
@@ -340,7 +340,7 @@ njs_vm_run(njs_vm_t *vm)
         return ret;
     }
 
-    if (nxt_slow_path(ret != NXT_DONE)) {
+    if (nxt_slow_path(ret != NJS_STOP)) {
         nxt_thread_log_debug("VM: ERROR");
         return ret;
     }