skeleton implementation for ServiceDocumenter compiler plugin

Change-Id: I6a9c957c0c4dac16365d269e57c30210619d23c9

compilerplugins/clang/getimplementationname.cxx

+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * 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/.
+ */
+
+#include <cassert>
+
+#include "plugin.hxx"
+
+namespace {
+
+clang::Expr const * ignoreParenImplicitComma(clang::Expr const * expr) {
+    for (;;) {
+        auto const e1 = expr->IgnoreParens()->IgnoreImplicit();
+        if (e1 != expr) {
+            expr = e1;
+            continue;
+        }
+        // auto const e1 = dyn_cast<clang::ExprWithCleanups>(expr);
+        // if (e1 != nullptr) {
+        //     expr = e1->getSubExpr();
+        //     continue;
+        // }
+        auto const e2 = dyn_cast<clang::BinaryOperator>(expr);
+        if (e2 != nullptr && e2->getOpcode() == clang::BO_Comma) {
+            expr = e2->getRHS();
+            continue;
+        }
+        return expr;
+    }
+}
+
+bool isPlainChar(clang::QualType type) {
+    return type->isSpecificBuiltinType(clang::BuiltinType::Char_S)
+        || type->isSpecificBuiltinType(clang::BuiltinType::Char_U);
+}
+
+bool overridesXServiceInfo(clang::CXXMethodDecl const * decl) {
+    for (auto i = decl->begin_overridden_methods();
+         i != decl->end_overridden_methods(); ++i)
+    {
+        if (((*i)->getParent()->getQualifiedNameAsString()
+             == "com::sun::star::lang::XServiceInfo")
+            || overridesXServiceInfo(*i))
+        {
+            return true;
+        }
+    }
+    return false;
+}
+
+class GetImplementationName:
+    public clang::RecursiveASTVisitor<GetImplementationName>,
+    public loplugin::Plugin
+{
+public:
+    explicit GetImplementationName(InstantiationData const & data): Plugin(data)
+    {}
+
+    void run() override;
+
+    bool VisitCXXMethodDecl(clang::CXXMethodDecl const * decl);
+
+private:
+    bool isStringConstant(Expr const * expr, clang::StringRef * string);
+
+    bool returnsStringConstant(
+        FunctionDecl const * decl, clang::StringRef * string);
+};
+
+void GetImplementationName::run() {
+    if (compiler.getLangOpts().CPlusPlus) {
+        TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+    }
+}
+
+bool GetImplementationName::VisitCXXMethodDecl(
+    clang::CXXMethodDecl const * decl)
+{
+    if (ignoreLocation(decl) || !decl->doesThisDeclarationHaveABody()
+        || !decl->isVirtual())
+    {
+        return true;
+    }
+    auto const id = decl->getIdentifier();
+    if (id == nullptr || id->getName() != "getImplementationName"
+        || !overridesXServiceInfo(decl))
+    {
+        return true;
+    }
+    clang::StringRef str;
+    if (!returnsStringConstant(decl, &str)) {
+        report(
+            clang::DiagnosticsEngine::Warning,
+            "cannot determine returned string", decl->getLocation())
+            << decl->getSourceRange();
+        return true;
+    }
+    report(
+        clang::DiagnosticsEngine::Warning, "\"%0\" implemented by %1",
+        decl->getLocation())
+        << str << decl->getParent()->getQualifiedNameAsString()
+        << decl->getSourceRange();
+    return true;
+}
+
+bool GetImplementationName::isStringConstant(
+    Expr const * expr, clang::StringRef * string)
+{
+    QualType t = expr->getType();
+    if (!(t->isConstantArrayType() && t.isConstQualified()
+          && isPlainChar(t->getAsArrayTypeUnsafe()->getElementType())))
+    {
+        return false;
+    }
+    DeclRefExpr const * dre = dyn_cast<DeclRefExpr>(expr);
+    if (dre != nullptr) {
+        VarDecl const * var = dyn_cast<VarDecl>(dre->getDecl());
+        if (var != nullptr) {
+            Expr const * init = var->getAnyInitializer();
+            if (init != nullptr) {
+                expr = ignoreParenImplicitComma(init);
+            }
+        }
+    }
+    StringLiteral const * lit = dyn_cast<StringLiteral>(expr);
+    if (lit != nullptr) {
+        if (!lit->isAscii()) {
+            return false;
+        }
+        *string = lit->getString();
+        return true;
+    }
+    APValue v;
+    if (!expr->isCXX11ConstantExpr(compiler.getASTContext(), &v)) {
+        return false;
+    }
+    switch (v.getKind()) {
+    case APValue::LValue:
+        return false; //TODO
+    case APValue::Array:
+        {
+            if (v.hasArrayFiller()) { //TODO: handle final NUL filler?
+                return false;
+            }
+            unsigned n = v.getArraySize();
+            assert(n != 0);
+            for (unsigned i = 0; i != n; ++i) {
+                APValue e(v.getArrayInitializedElt(i));
+                if (!e.isInt()) { //TODO: assert?
+                    return false;
+                }
+                APSInt iv = e.getInt();
+                if (iv == 0) {
+                    if (i == n -1) {
+                        continue;
+                    }
+                    return false;
+                } else if (iv.uge(0x80)) {
+                    return false;
+                }
+                //TODO
+            }
+            return false;//TODO
+        }
+    default:
+        assert(false); //TODO???
+        return "BAD11";
+    }
+}
+
+bool GetImplementationName::returnsStringConstant(
+    FunctionDecl const * decl, clang::StringRef * string)
+{
+    auto s1 = decl->getBody();
+    if (s1 == nullptr) {
+        return false;
+    }
+    for (;;) {
+        auto s2 = dyn_cast<clang::CompoundStmt>(s1);
+        if (s2 == nullptr) {
+            auto const s3 = dyn_cast<clang::CXXTryStmt>(s1);
+            if (s3 == nullptr) {
+                break;
+            }
+            s2 = s3->getTryBlock();
+        }
+        if (s2->size() != 1) {
+            break;
+        }
+        s1 = s2->body_front();
+    }
+    auto const s4 = dyn_cast<clang::ReturnStmt>(s1);
+    if (s4 == nullptr) {
+        return false;
+    }
+    for (auto e1 = ignoreParenImplicitComma(s4->getRetValue());;) {
+        auto const e2 = dyn_cast<clang::CallExpr>(e1);
+        if (e2 != nullptr) {
+            auto const d = e2->getDirectCallee();
+            return d != nullptr && returnsStringConstant(d, string);
+        }
+        auto const e3 = dyn_cast<clang::CXXFunctionalCastExpr>(e1);
+        if (e3 != nullptr) {
+            e1 = ignoreParenImplicitComma(e3->getSubExpr());
+            continue;
+        }
+        auto const e4 = dyn_cast<clang::CXXConstructExpr>(e1);
+        if (e4 != nullptr)  {
+            if (e4->getNumArgs() < 1) {
+                return false;
+            }
+            e1 = ignoreParenImplicitComma(e4->getArg(0));
+            continue;
+        }
+        return isStringConstant(e1, string);
+    }
+}
+
+loplugin::Plugin::Registration<GetImplementationName> X(
+    "getimplementationname");
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */