Index: ceval.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Python/ceval.c,v
retrieving revision 2.406
diff -c -r2.406 ceval.c
*** ceval.c	26 Jun 2004 04:34:33 -0000	2.406
--- ceval.c	27 Jun 2004 20:37:59 -0000
***************
*** 87,92 ****
--- 87,94 ----
  static void set_exc_info(PyThreadState *, PyObject *, PyObject *, PyObject *);
  static void reset_exc_info(PyThreadState *);
  static void format_exc_check_arg(PyObject *, char *, PyObject *);
+ static PyObject *string_concatenate(PyFrameObject *, PyObject *, PyObject *,
+ 				       unsigned char *);
  
  #define NAME_ERROR_MSG \
  	"name '%.200s' is not defined"
***************
*** 552,557 ****
--- 554,560 ----
  #define INSTR_OFFSET()	(next_instr - first_instr)
  #define NEXTOP()	(*next_instr++)
  #define NEXTARG()	(next_instr += 2, (next_instr[-1]<<8) + next_instr[-2])
+ #define PEEKARG()	((next_instr[2]<<8) + next_instr[1])
  #define JUMPTO(x)	(next_instr = first_instr + (x))
  #define JUMPBY(x)	(next_instr += (x))
  
***************
*** 582,589 ****
  #endif
  
  #define PREDICTED(op)		PRED_##op: next_instr++
! #define PREDICTED_WITH_ARG(op)	PRED_##op: oparg = (next_instr[2]<<8) + \
! 				next_instr[1]; next_instr += 3
  
  /* Stack manipulation macros */
  
--- 585,591 ----
  #endif
  
  #define PREDICTED(op)		PRED_##op: next_instr++
! #define PREDICTED_WITH_ARG(op)	PRED_##op: oparg = PEEKARG(); next_instr += 3
  
  /* Stack manipulation macros */
  
***************
*** 1068,1073 ****
--- 1070,1084 ----
  					goto slow_add;
  				x = PyInt_FromLong(i);
  			}
+ 			else if (PyString_CheckExact(v) &&
+ 				 PyString_CheckExact(w)) {
+ 				x = string_concatenate(f, v, w, next_instr);
+ 				/* Py_DECREF(v); done by string_concatenate */
+ 				Py_DECREF(w);
+ 				SET_TOP(x);
+ 				if (x != NULL) continue;
+ 				break;
+ 			}
  			else {
  			  slow_add:
  				x = PyNumber_Add(v, w);
***************
*** 1263,1268 ****
--- 1274,1288 ----
  					goto slow_iadd;
  				x = PyInt_FromLong(i);
  			}
+ 			else if (PyString_CheckExact(v) &&
+ 				 PyString_CheckExact(w)) {
+ 				x = string_concatenate(f, v, w, next_instr);
+ 				/* Py_DECREF(v); done by string_concatenate */
+ 				Py_DECREF(w);
+ 				SET_TOP(x);
+ 				if (x != NULL) continue;
+ 				break;
+ 			}
  			else {
  			  slow_iadd:
  				x = PyNumber_InPlaceAdd(v, w);
***************
*** 4188,4193 ****
--- 4208,4292 ----
  	PyErr_Format(exc, format_str, obj_str);
  }
  
+ static int
+ fast_inplace_concat(PyObject **pv, PyObject *w)
+ {
+ 	int v_size = PyString_GET_SIZE(*pv);
+ 	int w_size = PyString_GET_SIZE(w);
+ 	int newsize = v_size + w_size;
+ 	PyStringObject *sv;
+ 	
+ 	/* We have to inline _PyString_Resize() to change a detail:
+ 	   if memory runs out, we must not deallocate the old string. */
+ 	
+ 	assert((*pv)->ob_refcnt == 1);
+ 	/* XXX UNREF/NEWREF interface should be more symmetrical */
+ 	_Py_DEC_REFTOTAL;
+ 	_Py_ForgetReference(*pv);
+ 	sv = (PyStringObject *)
+ 		PyObject_REALLOC((char *)(*pv),
+ 			sizeof(PyStringObject) + newsize * sizeof(char));
+ 	if (sv == NULL) {
+ 		_Py_NewReference(*pv);
+ 		PyErr_NoMemory();
+ 		return -1;
+ 	}
+ 	_Py_NewReference((PyObject *)sv);
+ 	sv->ob_size = newsize;
+ 	sv->ob_sval[newsize] = '\0';
+ 	memcpy(sv->ob_sval + v_size, PyString_AS_STRING(w), w_size);
+ 	*pv = (PyObject *)sv;
+ 	return 0;
+ }
+ 
+ static PyObject *
+ string_concatenate(PyFrameObject *f, PyObject *v, PyObject *w,
+ 		   unsigned char *next_instr)
+ {
+ 	if (v->ob_refcnt == 1) {
+ 		if (fast_inplace_concat(&v, w)) {
+ 			Py_DECREF(v);
+ 			return NULL;
+ 		}
+ 		return v;
+ 	}
+ 	if (v->ob_refcnt == 2) {
+ 		if (*next_instr == STORE_FAST) {
+ 			int oparg = PEEKARG();
+ 			PyObject **fastlocals = f->f_localsplus;
+ 			if (GETLOCAL(oparg) != v)
+ 				goto fallback;
+ 			Py_DECREF(v);
+ 			if (fast_inplace_concat(&v, w))
+ 				return NULL;
+ 			Py_INCREF(v);
+ 			GETLOCAL(oparg) = v;
+ 			return v;
+ 		}
+ 		else if (*next_instr == STORE_NAME) {
+ 			PyObject *names = f->f_code->co_names;
+ 			PyObject *name = GETITEM(names, PEEKARG());
+ 			PyDictEntry *e;
+ 			PyDictObject *d = (PyDictObject *)f->f_locals;
+ 			long hash = ((PyStringObject *)name)->ob_shash;
+ 			if (d == NULL || hash == -1)
+ 				goto fallback;
+ 			e = d->ma_lookup(d, name, hash);
+ 			if (e->me_value != v)
+ 				goto fallback;
+ 			Py_DECREF(v);
+ 			if (fast_inplace_concat(&v, w))
+ 				return NULL;
+ 			Py_INCREF(v);
+ 			e->me_value = v;
+ 			return v;
+ 		}
+ 	}
+    fallback:
+ 	PyString_Concat(&v, w);
+ 	return v;
+ }
+ 
  #ifdef DYNAMIC_EXECUTION_PROFILE
  
  static PyObject *