Allow nogil bounds checking for buffers/memoryviews

Cython/Compiler/Buffer.py

@@ -412,7 +412,7 @@ def put_assign_to_buffer(lhs_cname, rhs_cname, buf_entry,
     code.putln("}") # Release stack
 
 def put_buffer_lookup_code(entry, index_signeds, index_cnames, directives,
-                           pos, code, negative_indices):
+                           pos, code, negative_indices, in_nogil_context):
     """
     Generates code to process indices and calculate an offset into
     a buffer. Returns a C string which gives a pointer which can be
@@ -455,9 +455,16 @@ def put_buffer_lookup_code(entry, index_signeds, index_cnames, directives,
             code.putln("if (%s) %s = %d;" % (
                 code.unlikely("%s >= %s%s" % (cname, cast, shape)),
                               tmp_cname, dim))
-        code.globalstate.use_utility_code(raise_indexerror_code)
+
+        if in_nogil_context:
+            code.globalstate.use_utility_code(raise_indexerror_nogil)
+            func = '__Pyx_RaiseBufferIndexErrorNogil'
+        else:
+            code.globalstate.use_utility_code(raise_indexerror_code)
+            func = '__Pyx_RaiseBufferIndexError'
+
         code.putln("if (%s) {" % code.unlikely("%s != -1" % tmp_cname))
-        code.putln('__Pyx_RaiseBufferIndexError(%s);' % tmp_cname)
+        code.putln('%s(%s);' % (func, tmp_cname))
         code.putln(code.error_goto(pos))
         code.putln('}')
         code.funcstate.release_temp(tmp_cname)
@@ -768,6 +775,7 @@ buffer_struct_declare_code = load_buffer_utility("BufferStructDeclare",
 # Utility function to set the right exception
 # The caller should immediately goto_error
 raise_indexerror_code = load_buffer_utility("BufferIndexError")
+raise_indexerror_nogil = load_buffer_utility("BufferIndexErrorNogil")
 
 parse_typestring_repeat_code = UtilityCode(
 proto = """

Cython/Compiler/ExprNodes.py

@@ -2812,9 +2812,11 @@ class IndexNode(ExprNode):
     def nogil_check(self, env):
         if self.is_buffer_access or self.memslice_index or self.memslice_slice:
             if not self.memslice_slice and env.directives['boundscheck']:
-                error(self.pos, "Cannot check buffer index bounds without gil; use boundscheck(False) directive")
-                return
-            elif self.type.is_pyobject:
+                # error(self.pos, "Cannot check buffer index bounds without gil; "
+                #                 "use boundscheck(False) directive")
+                warning(self.pos, "Use boundscheck(False) for faster access",
+                        level=1)
+            if self.type.is_pyobject:
                 error(self.pos, "Cannot access buffer with object dtype without gil")
                 return
         super(IndexNode, self).nogil_check(env)
@@ -3084,7 +3086,8 @@ class IndexNode(ExprNode):
                index_cnames=index_temps,
                directives=code.globalstate.directives,
                pos=self.pos, code=code,
-               negative_indices=negative_indices)
+               negative_indices=negative_indices,
+               in_nogil_context=self.in_nogil_context)
 
     def put_memoryviewslice_slice_code(self, code):
         "memslice[:]"
@@ -9681,7 +9684,7 @@ static void __Pyx_RaiseUnboundMemoryviewSliceNogil(const char *varname) {
     PyGILState_STATE gilstate = PyGILState_Ensure();
     #endif
     __Pyx_RaiseUnboundLocalError(varname);
-    #ifdef WITH_THREAD")
+    #ifdef WITH_THREAD
     PyGILState_Release(gilstate);
     #endif
 }

Cython/Utility/Buffer.c

@@ -26,6 +26,22 @@ static void __Pyx_RaiseBufferIndexError(int axis) {
      "Out of bounds on buffer access (axis %d)", axis);
 }
 
+/////////////// BufferIndexErrorNogil.proto ///////////////
+//@requires: BufferIndexError
+
+static void __Pyx_RaiseBufferIndexErrorNogil(int axis); /*proto*/
+
+/////////////// BufferIndexErrorNogil ///////////////
+static void __Pyx_RaiseBufferIndexErrorNogil(int axis) {
+    #ifdef WITH_THREAD
+    PyGILState_STATE gilstate = PyGILState_Ensure();
+    #endif
+    __Pyx_RaiseBufferIndexError(axis);
+    #ifdef WITH_THREAD
+    PyGILState_Release(gilstate);
+    #endif
+}
+
 /////////////// BufferFallbackError.proto ///////////////
 static void __Pyx_RaiseBufferFallbackError(void); /*proto*/
 

tests/run/bufaccess.pyx

@@ -1114,3 +1114,16 @@ def buffer_nogil():
     with nogil:
         buf[1] = 10
     return buf[1]
+
+@testcase
+def buffer_nogil_oob():
+    """
+    >>> buffer_nogil_oob()
+    Traceback (most recent call last):
+        ...
+    IndexError: Out of bounds on buffer access (axis 0)
+    """
+    cdef object[int] buf = IntMockBuffer(None, [1,2,3])
+    with nogil:
+        buf[5] = 10
+    return buf[1]

tests/run/memoryview.pyx

@@ -209,6 +209,18 @@ def test_nogil_unbound_localerror():
     with nogil:
         m[0] = 10
 
+def test_nogil_oob():
+    """
+    >>> test_nogil_oob()
+    Traceback (most recent call last):
+        ...
+    IndexError: Out of bounds on buffer access (axis 0)
+    """
+    cdef int[5] a
+    cdef int[:] m = a
+    with nogil:
+        m[5] = 1
+
 def basic_struct(MyStruct[:] mslice):
     """
     See also buffmt.pyx