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-rw-r--r--compilerplugins/clang/cow_wrapper.cxx121
1 files changed, 121 insertions, 0 deletions
diff --git a/compilerplugins/clang/cow_wrapper.cxx b/compilerplugins/clang/cow_wrapper.cxx
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index 0000000000..c98f70cbeb
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+++ b/compilerplugins/clang/cow_wrapper.cxx
@@ -0,0 +1,121 @@
+/* -*- 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.
+ *
+ */
+#ifndef LO_CLANG_SHARED_PLUGINS
+
+#include <cassert>
+#include <string>
+#include <iostream>
+#include <fstream>
+#include <set>
+#include <unordered_set>
+#include "plugin.hxx"
+#include "check.hxx"
+
+/*
+Look for places where we are using cow_wrapper, but we are calling a const method on the impl object
+with a non-const pointer, which means we will unnecessarily trigger a copy.
+*/
+
+namespace
+{
+class Cow_Wrapper : public loplugin::FilteringPlugin<Cow_Wrapper>
+{
+public:
+ explicit Cow_Wrapper(loplugin::InstantiationData const& data)
+ : FilteringPlugin(data)
+ {
+ }
+
+ virtual bool preRun() override { return true; }
+
+ virtual void run() override
+ {
+ if (preRun())
+ TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+ }
+
+ bool VisitCXXMemberCallExpr(const CXXMemberCallExpr*);
+};
+
+bool Cow_Wrapper::VisitCXXMemberCallExpr(const CXXMemberCallExpr* memberCallExpr)
+{
+ if (ignoreLocation(memberCallExpr))
+ return true;
+ auto methodDecl = memberCallExpr->getMethodDecl();
+ if (!methodDecl || !methodDecl->isConst())
+ return true;
+
+ auto expr = memberCallExpr->getImplicitObjectArgument()->IgnoreImplicit()->IgnoreParens();
+ auto operatorCallExpr = dyn_cast<CXXOperatorCallExpr>(expr);
+
+ if (operatorCallExpr && operatorCallExpr->getOperator() == OO_Arrow)
+ {
+ auto arrowMethodDecl = dyn_cast_or_null<CXXMethodDecl>(operatorCallExpr->getDirectCallee());
+ if (!arrowMethodDecl)
+ return true;
+ if (arrowMethodDecl->isConst())
+ return true;
+ auto dc = loplugin::DeclCheck(arrowMethodDecl->getParent())
+ .Class("cow_wrapper")
+ .Namespace("o3tl")
+ .GlobalNamespace();
+ if (!dc)
+ return true;
+ }
+ else if (operatorCallExpr)
+ {
+ auto methodDecl2 = dyn_cast_or_null<CXXMethodDecl>(operatorCallExpr->getDirectCallee());
+ if (!methodDecl2)
+ return true;
+ auto dc = loplugin::DeclCheck(methodDecl2->getParent())
+ .Class("cow_wrapper")
+ .Namespace("o3tl")
+ .GlobalNamespace();
+ if (!dc)
+ return true;
+ }
+ else if (auto callExpr = dyn_cast<CallExpr>(expr))
+ {
+ if (!isa<ImplicitCastExpr>(callExpr->getCallee())) // std::as_const shows up as this
+ return true;
+ if (callExpr->getNumArgs() < 1)
+ return true;
+ auto arg0 = dyn_cast<CXXOperatorCallExpr>(callExpr->getArg(0));
+ if (!arg0)
+ return true;
+ auto starMethodDecl = dyn_cast_or_null<CXXMethodDecl>(arg0->getDirectCallee());
+ if (!starMethodDecl)
+ return true;
+ auto dc = loplugin::DeclCheck(starMethodDecl->getParent())
+ .Class("cow_wrapper")
+ .Namespace("o3tl")
+ .GlobalNamespace();
+ if (!dc)
+ return true;
+ }
+ else
+ return true;
+
+ report(DiagnosticsEngine::Warning,
+ "calling const method on o3tl::cow_wrapper impl class via non-const pointer, rather use "
+ "std::as_const to prevent triggering an unnecessary copy",
+ memberCallExpr->getBeginLoc())
+ << memberCallExpr->getSourceRange();
+ return true;
+}
+
+loplugin::Plugin::Registration<Cow_Wrapper> cow_wrapper("cow_wrapper", true);
+
+} // namespace
+
+#endif // LO_CLANG_SHARED_PLUGINS
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */