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-rw-r--r--compilerplugins/clang/store/cascadingassignop.cxx94
1 files changed, 94 insertions, 0 deletions
diff --git a/compilerplugins/clang/store/cascadingassignop.cxx b/compilerplugins/clang/store/cascadingassignop.cxx
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+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * Based on LLVM/Clang.
+ *
+ * This file is distributed under the University of Illinois Open Source
+ * License. See LICENSE.TXT for details.
+ *
+ */
+
+#include "cascadingassignop.hxx"
+
+/*
+This is a compile check.
+
+It checks for complex statements with conditional operators in conditional
+operators, which are error prone, e.g.
+ Thing foo = IsBar() ? ( IsBaz() ? b1 : b2 ) : b3;
+
+However, it finds 556 cases in sw/source alone, thus likely needs some more
+restricting, e.g. by checking for multiline conditional operator statements or
+a certain length in characters (but that needs the Context/SourceManager, which
+I haven't played with yet).
+*/
+
+// the value is rather arbitrary, but code above this number of stmts begins to
+// be smelly
+static const int stmtlimit = 20;
+
+namespace loplugin
+{
+
+struct WalkCounter
+{
+ int stmtcount;
+ bool cascading;
+ bool conditionals;
+};
+
+// Ctor, nothing special, pass the argument(s).
+CascadingAssignOp::CascadingAssignOp( const InstantiationData& data )
+ : FilteringPlugin( data )
+{
+}
+
+// Perform the actual action.
+void CascadingAssignOp::run()
+{
+ // Traverse the whole AST of the translation unit (i.e. examine the whole source file).
+ // The Clang AST helper class will call VisitReturnStmt for every return statement.
+ TraverseDecl( compiler.getASTContext().getTranslationUnitDecl());
+}
+
+void CascadingAssignOp::Walk( const Stmt* stmt, WalkCounter& c )
+{
+ for(Stmt::const_child_iterator it = stmt->child_begin(); it != stmt->child_end(); ++it)
+ {
+ ++c.stmtcount;
+ const BinaryOperator* binop = dyn_cast< BinaryOperator >( *it );
+ if ( binop )
+ {
+ if ( (binop->isAssignmentOp() || binop->isCompoundAssignmentOp()))
+ c.cascading = true;
+ if ( dyn_cast< AbstractConditionalOperator >( binop ) || binop->isLogicalOp())
+ c.conditionals = true;
+ }
+ Walk(*it, c);
+ }
+}
+
+bool CascadingAssignOp::VisitStmt( const Stmt* stmt )
+{
+ const BinaryOperator* binop = dyn_cast< BinaryOperator >( stmt );
+ if ( binop && (binop->isAssignmentOp() || binop->isCompoundAssignmentOp()))
+ {
+ WalkCounter c = { 0, false, false };
+ Walk(binop, c);
+ if(c.cascading && c.conditionals && c.stmtcount >= stmtlimit)
+ {
+ std::string msg("cascading assign operator mixing in conditionals, complexity: ");
+ msg.append(std::to_string(c.stmtcount));
+ report( DiagnosticsEngine::Warning, msg, binop->getLocStart());
+ }
+ }
+ return true;
+}
+
+// Register the plugin action with the LO plugin handling.
+static Plugin::Registration< CascadingAssignOp > X( "cascadingassignop" );
+
+} // namespace loplugin
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */