Work around clang --analyze warnings

clang doesn't understand the invariants guaranteed for specific AST node
types and, when seeing null pointer checks in optimize(), assumes any
pointers in the node might be null. Work around this by adding explicit
- redundant - null pointer checks.

1 files changed, 8 insertions, 4 deletions

diff --git a/src/pugixml.cpp b/src/pugixml.cpp
index e8a9daa..fc0fd87 100644
--- a/src/pugixml.cpp
+++ b/src/pugixml.cpp
@@ -10871,13 +10871,14 @@ PUGI__NS_BEGIN
 			// Rewrite [position()=expr] with [expr]
 			// Note that this step has to go before classification to recognize [position()=1]
 			if ((_type == ast_filter || _type == ast_predicate) &&
+				_right && // workaround for clang static analyzer (_right is never null for ast_filter/ast_predicate)
 				_right->_type == ast_op_equal && _right->_left->_type == ast_func_position && _right->_right->_rettype == xpath_type_number)
 			{
 				_right = _right->_right;
 			}
 
 			// Classify filter/predicate ops to perform various optimizations during evaluation
-			if (_type == ast_filter || _type == ast_predicate)
+			if ((_type == ast_filter || _type == ast_predicate) && _right) // workaround for clang static analyzer (_right is never null for ast_filter/ast_predicate)
 			{
 				assert(_test == predicate_default);
 
@@ -10893,8 +10894,8 @@ PUGI__NS_BEGIN
 			// The former is a full form of //foo, the latter is much faster since it executes the node test immediately
 			// Do a similar kind of rewrite for self/descendant/descendant-or-self axes
 			// Note that we only rewrite positionally invariant steps (//foo[1] != /descendant::foo[1])
-			if (_type == ast_step && (_axis == axis_child || _axis == axis_self || _axis == axis_descendant || _axis == axis_descendant_or_self) && _left &&
-				_left->_type == ast_step && _left->_axis == axis_descendant_or_self && _left->_test == nodetest_type_node && !_left->_right &&
+			if (_type == ast_step && (_axis == axis_child || _axis == axis_self || _axis == axis_descendant || _axis == axis_descendant_or_self) &&
+				_left && _left->_type == ast_step && _left->_axis == axis_descendant_or_self && _left->_test == nodetest_type_node && !_left->_right &&
 				is_posinv_step())
 			{
 				if (_axis == axis_child || _axis == axis_descendant)
@@ -10906,7 +10907,9 @@ PUGI__NS_BEGIN
 			}
 
 			// Use optimized lookup table implementation for translate() with constant arguments
-			if (_type == ast_func_translate && _right->_type == ast_string_constant && _right->_next->_type == ast_string_constant)
+			if (_type == ast_func_translate &&
+				_right && // workaround for clang static analyzer (_right is never null for ast_func_translate)
+				_right->_type == ast_string_constant && _right->_next->_type == ast_string_constant)
 			{
 				unsigned char* table = translate_table_generate(alloc, _right->_data.string, _right->_next->_data.string);
 
@@ -10919,6 +10922,7 @@ PUGI__NS_BEGIN
 
 			// Use optimized path for @attr = 'value' or @attr = $value
 			if (_type == ast_op_equal &&
+				_left && // workaround for clang static analyzer (_left is never null for ast_op_equal)
 				_left->_type == ast_step && _left->_axis == axis_attribute && _left->_test == nodetest_name && !_left->_left && !_left->_right &&
 				(_right->_type == ast_string_constant || (_right->_type == ast_variable && _right->_rettype == xpath_type_string)))
 			{