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-rw-r--r--compilerplugins/clang/classmemaccess.cxx133
1 files changed, 133 insertions, 0 deletions
diff --git a/compilerplugins/clang/classmemaccess.cxx b/compilerplugins/clang/classmemaccess.cxx
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+++ b/compilerplugins/clang/classmemaccess.cxx
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+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#ifndef LO_CLANG_SHARED_PLUGINS
+
+#include "check.hxx"
+#include "plugin.hxx"
+
+// Similar to GCC "warning: ‘void* memset(void*, int, size_t)’ writing to an object of non-trivial
+// type ‘...’; use assignment instead [-Wclass-memaccess]", but looking through toplevel cast to
+// void* and taking arrays into account in addition to pointers. (Clang has
+// -Wdynamic-class-memaccess, but that only warns about memset overwriting a vtable pointer. GCC
+// deliberately does not warn when there is a toplevel cast to void*, see
+// <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81327> "[8 Regression] cast to void* does not
+// suppress -Wclass-memaccess".)
+
+namespace
+{
+class ClassMemAccess final : public loplugin::FilteringPlugin<ClassMemAccess>
+{
+public:
+ explicit ClassMemAccess(loplugin::InstantiationData const& data)
+ : FilteringPlugin(data)
+ {
+ }
+
+ bool VisitCallExpr(CallExpr const* expr)
+ {
+ if (ignoreLocation(expr))
+ {
+ return true;
+ }
+ auto const fdecl = expr->getDirectCallee();
+ if (fdecl == nullptr)
+ {
+ return true;
+ }
+ auto dc = loplugin::DeclCheck(fdecl).Function("memset");
+ if (!(dc.GlobalNamespace() || dc.StdNamespace()))
+ {
+ return true;
+ }
+ if (expr->getNumArgs() != 3)
+ {
+ if (isDebugMode())
+ {
+ report(DiagnosticsEngine::Fatal,
+ "unexpected call to %0 with %1 instead of 3 arguments", expr->getExprLoc())
+ << fdecl << expr->getNumArgs() << expr->getSourceRange();
+ report(DiagnosticsEngine::Note, "%0 declared here", fdecl->getLocation())
+ << fdecl << fdecl->getSourceRange();
+ }
+ return true;
+ }
+ auto e = expr->getArg(0)->IgnoreParenImpCasts();
+ while (auto const cast = dyn_cast<ExplicitCastExpr>(e))
+ {
+ if (!loplugin::TypeCheck(cast->getTypeAsWritten()).Pointer().Void())
+ {
+ break;
+ }
+ e = cast->getSubExprAsWritten()->IgnoreParenImpCasts();
+ }
+ QualType t;
+ if (auto const t1 = e->getType()->getAs<clang::PointerType>())
+ {
+ t = t1->getPointeeType();
+ }
+ else if (e->getType()->isArrayType())
+ {
+ t = e->getType();
+ while (auto const t2 = t->getAsArrayTypeUnsafe())
+ {
+ t = t2->getElementType();
+ }
+ }
+ else
+ {
+ if (isDebugMode())
+ {
+ report(DiagnosticsEngine::Fatal,
+ "unexpected call to %0 with first argument of non-pointer type %1",
+ expr->getExprLoc())
+ << fdecl << e->getType() << expr->getSourceRange();
+ report(DiagnosticsEngine::Note, "%0 declared here", fdecl->getLocation())
+ << fdecl << fdecl->getSourceRange();
+ }
+ return true;
+ }
+ auto const decl = t->getAsCXXRecordDecl();
+ if (decl == nullptr)
+ {
+ return true;
+ }
+ if (!decl->isCompleteDefinition())
+ {
+ return true; // conservatively assume it may be trivial
+ }
+ if (decl->isTrivial())
+ {
+ return true;
+ }
+ report(DiagnosticsEngine::Warning,
+ "%0 writing to an object of non-trivial type %1; use assignment instead",
+ expr->getExprLoc())
+ << fdecl << decl << expr->getSourceRange();
+ return true;
+ }
+
+ bool preRun() override { return compiler.getLangOpts().CPlusPlus; }
+
+private:
+ void run() override
+ {
+ if (preRun())
+ {
+ TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+ }
+ }
+};
+
+loplugin::Plugin::Registration<ClassMemAccess> classmemaccess("classmemaccess");
+}
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */