Works with some assignment expressions

Cython/Compiler/ExprNodes.py

@@ -1339,6 +1339,9 @@ class IndexNode(ExprNode):
         return 1
     
     def calculate_result_code(self):
+        if self.is_buffer_access:
+            return "<not needed>"
+        else:
             return "(%s[%s])" % (
                 self.base.result_code, self.index.result_code)
             
@@ -3842,6 +3845,10 @@ class CoerceToPyTypeNode(CoercionNode):
 
     gil_message = "Converting to Python object"
 
+    def analyse_types(self, env):
+        # The arg is always already analysed
+        pass
+
     def generate_result_code(self, code):
         function = self.arg.type.to_py_function
         code.putln('%s = %s(%s); %s' % (
@@ -3866,6 +3873,10 @@ class CoerceFromPyTypeNode(CoercionNode):
             error(arg.pos,
                 "Obtaining char * from temporary Python value")
     
+    def analyse_types(self, env):
+        # The arg is always already analysed
+        pass
+
     def generate_result_code(self, code):
         function = self.type.from_py_function
         operand = self.arg.py_result()

Cython/Compiler/ParseTreeTransforms.py

@@ -155,6 +155,7 @@ class BufferTransform(CythonTransform):
     def __call__(self, node):
         cymod = self.context.modules[u'__cython__']
         self.buffer_type = cymod.entries[u'Py_buffer'].type
+        self.lhs = False
         return super(BufferTransform, self).__call__(node)
 
     def handle_scope(self, node, scope):
@@ -229,10 +230,29 @@ class BufferTransform(CythonTransform):
 #                            attribute=EncodedString("strides")),
 #                        index=IntNode(node.pos, value=EncodedString(idx))))
 #                print ass.dump()
+
     def visit_SingleAssignmentNode(self, node):
-        self.visitchildren(node)
+        # On assignments, two buffer-related things can happen:
+        # a) A buffer variable is assigned to (reacquisition)
+        # b) Buffer access assignment: arr[...] = ...
+        # Since we don't allow nested buffers, these don't overlap.
+        
+#        self.lhs = True
+        self.visit(node.rhs)
+        self.visit(node.lhs)
+#        self.lhs = False
+#        self.visitchildren(node)
+        # Only acquire buffers on vars (not attributes) for now.
+        if isinstance(node.lhs, NameNode) and node.lhs.entry.buffer_aux:
+            # Is buffer variable
+            return self.reacquire_buffer(node)
+        elif (isinstance(node.lhs, IndexNode) and
+              isinstance(node.lhs.base, NameNode) and
+              node.lhs.base.entry.buffer_aux is not None):
+            return self.assign_into_buffer(node)
+        
+    def reacquire_buffer(self, node):
         bufaux = node.lhs.entry.buffer_aux
-        if bufaux is not None:
         auxass = []
         for idx, entry in enumerate(bufaux.stridevars):
             entry.used = True
@@ -267,37 +287,48 @@ class BufferTransform(CythonTransform):
         acq.analyse_declarations(self.scope)
         acq.analyse_expressions(self.scope)
         stats = acq.stats
-#            stats += [node] # Do assignment after successful buffer acquisition
-         #   print acq.dump()
         return stats
-        else:
-            return node
 
-    buffer_access = TreeFragment(u"""
-        (<unsigned char*>(BUF.buf + OFFSET))[0]
-    """)
-    def visit_IndexNode(self, node):
-        if node.is_buffer_access:
-            assert node.index is None
-            assert node.indices is not None
+    def assign_into_buffer(self, node):
+        result = SingleAssignmentNode(node.pos,
+                                      rhs=self.visit(node.rhs),
+                                      lhs=self.buffer_index(node.lhs))
+        result.analyse_expressions(self.scope)
+        return result
+        
+
+    def buffer_index(self, node):
         bufaux = node.base.entry.buffer_aux
         assert bufaux is not None
-            to_sum = [ IntBinopNode(node.pos, operator='*', operand1=index,
+        # indices * strides...
+        to_sum = [ IntBinopNode(node.pos, operator='*',
+                                operand1=index, #PhaseEnvelopeNode(PhaseEnvelopeNode.ANALYSED, index),
                                 operand2=NameNode(node.pos, name=stride.name))
             for index, stride in zip(node.indices, bufaux.stridevars)]
-            print to_sum
 
-            indices = node.indices
-            # reduce * on indices
+        # then sum them 
         expr = to_sum[0]
         for next in to_sum[1:]:
             expr = IntBinopNode(node.pos, operator='+', operand1=expr, operand2=next)
+
         tmp= self.buffer_access.substitute({
             'BUF': NameNode(node.pos, name=bufaux.buffer_info_var.name),
             'OFFSET': expr
-                })
-            tmp.analyse_expressions(self.scope)
+            }, pos=node.pos)
+
         return tmp.stats[0].expr
+
+    buffer_access = TreeFragment(u"""
+        (<unsigned char*>(BUF.buf + OFFSET))[0]
+    """)
+    def visit_IndexNode(self, node):
+        # Only occurs when the IndexNode is an rvalue
+        if node.is_buffer_access:
+            assert node.index is None
+            assert node.indices is not None
+            result = self.buffer_index(node)
+            result.analyse_expressions(self.scope)
+            return result
         else:
             return node
 
@@ -309,6 +340,56 @@ class BufferTransform(CythonTransform):
 #        print node.dump()
     
 
+class PhaseEnvelopeNode(Node):
+    """
+    This node is used if you need to protect a node from reevaluation
+    of a phase. For instance, if you extract...
+
+    Use with care!
+    """
+
+    # Phases
+    PARSED, ANALYSED = range(2)
+
+    def __init__(self, phase, wrapped):
+        self.phase = phase
+        self.wrapped = wrapped
+
+    def get_pos(self): return self.wrapped.pos 
+    def set_pos(self, value): self.wrapped.pos  = value
+    pos = property(get_pos, set_pos)
+
+    def get_subexprs(self): return self.wrapped.subexprs
+    subexprs = property(get_subexprs)
+
+    def analyse_types(self, env):
+        if self.phase < self.ANALYSED:
+            self.wrapped.analyse_types(env)
+
+    def __getattribute__(self, attrname):
+        wrapped = object.__getattribute__(self, "wrapped")
+        phase = object.__getattribute__(self, "phase")
+        if attrname == "wrapped": return wrapped
+        if attrname == "phase": return phase
+        
+        attr = getattr(wrapped, attrname)
+
+        overridden = ("analyse_types",)
+
+
+        
+        print attrname, attr
+        if not isinstance(attr, Node):
+            return attr
+        else:
+            if attr is None: return None
+            else:
+                return PhaseEnvelopeNode(phase, attr)
+
+
+    
+
+
 class WithTransform(CythonTransform):
 
     # EXCINFO is manually set to a variable that contains