1 files changed, 294 insertions, 0 deletions
diff --git a/compilerplugins/clang/inlinesimplememberfunctions.cxx b/compilerplugins/clang/inlinesimplememberfunctions.cxx
new file mode 100644
index 000000000..760094b5a
--- /dev/null
+++ b/compilerplugins/clang/inlinesimplememberfunctions.cxx
@@ -0,0 +1,294 @@
+/* -*- 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 <string>
+
+#include "plugin.hxx"
+
+// Methods that purely return a local field should be declared in the header and be declared inline.
+// So that the compiler can elide the function call and turn it into a simple fixed-offset-load instruction.
+
+namespace {
+
+class InlineSimpleMemberFunctions:
+    public loplugin::FilteringRewritePlugin<InlineSimpleMemberFunctions>
+{
+public:
+    explicit InlineSimpleMemberFunctions(loplugin::InstantiationData const & data): FilteringRewritePlugin(data) {}
+
+    virtual void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
+
+    bool VisitCXXMethodDecl(const CXXMethodDecl * decl);
+private:
+    bool rewrite(const CXXMethodDecl * functionDecl);
+};
+
+static bool oneAndOnlyOne(clang::Stmt::const_child_range range) {
+    if (range.begin() == range.end()) {
+        return false;
+    }
+    if (++range.begin() != range.end()) {
+        return false;
+    }
+    return true;
+}
+
+
+bool InlineSimpleMemberFunctions::VisitCXXMethodDecl(const CXXMethodDecl * functionDecl) {
+    if (ignoreLocation(functionDecl)) {
+        return true;
+    }
+    // no point in doing virtual methods, the compiler always has to generate a vtable entry and a method
+    if (functionDecl->isVirtual()) {
+        return true;
+    }
+    if (functionDecl->getTemplatedKind() != FunctionDecl::TK_NonTemplate) {
+        return true;
+    }
+    if (!functionDecl->isInstance()) {
+        return true;
+    }
+    if (!functionDecl->isOutOfLine()) {
+        return true;
+    }
+    if( !functionDecl->hasBody()) {
+        return true;
+    }
+    if( functionDecl->isInlineSpecified()) {
+        return true;
+    }
+    if( functionDecl->getCanonicalDecl()->isInlineSpecified()) {
+        return true;
+    }
+    if( functionDecl->getNameAsString().find("Impl") != std::string::npos) {
+        return true;
+    }
+    // ignore stuff that forms part of the stable URE interface
+    if (isInUnoIncludeFile(functionDecl)) {
+        return true;
+    }
+    // ignore stuff like:
+    //   template<class E> E * Sequence<E>::begin() { return getArray(); }
+    if( functionDecl->getParent()->getDescribedClassTemplate() != nullptr ) {
+        return true;
+    }
+
+    /*
+      The chain here looks like
+        CompoundStmt
+          ReturnStmt
+            other stuff
+              CXXThisExpr
+    */
+
+    const CompoundStmt* compoundStmt = dyn_cast< CompoundStmt >( functionDecl->getBody() );
+    if (compoundStmt == nullptr) {
+        return true;
+    }
+    if (compoundStmt->body_begin() == compoundStmt->body_end()) {
+        return true;
+    }
+
+
+    const Stmt* childStmt = *compoundStmt->child_begin();
+
+    if (dyn_cast<ReturnStmt>( childStmt ) == nullptr) {
+        return true;
+    }
+    if (!oneAndOnlyOne(childStmt->children())) {
+        return true;
+    }
+
+
+    /* Don't warn if we see a method definition like
+         X X::a() {
+             return *this;
+         }
+      which translates to:
+        CompoundStmt
+          ReturnStmt
+            ImplicitCastExpr
+              UnaryOperator
+                CXXThisExpr
+      or:
+        CompoundStmt
+          ReturnStmt
+            UnaryOperator
+              CXXThisExpr
+    */
+    childStmt = *childStmt->child_begin();
+    if (dyn_cast<ImplicitCastExpr>( childStmt ) != nullptr
+        && oneAndOnlyOne( childStmt->children() ))
+    {
+        const Stmt* childStmt2 = *childStmt->child_begin();
+        if (dyn_cast<UnaryOperator>( childStmt2 ) != nullptr
+            && oneAndOnlyOne(childStmt2->children()))
+        {
+            childStmt2 = *childStmt2->child_begin();
+            if (dyn_cast<CXXThisExpr>( childStmt2 ) != nullptr
+                && childStmt2->children().begin() == childStmt2->children().end())
+            {
+                return true;
+            }
+        }
+    }
+    if (dyn_cast<UnaryOperator>( childStmt ) != nullptr
+        && oneAndOnlyOne( childStmt->children() ))
+    {
+        const Stmt* childStmt2 = *childStmt->child_begin();
+        if (dyn_cast<CXXThisExpr>( childStmt2 ) != nullptr
+            && childStmt2->children().begin() == childStmt2->children().end())
+        {
+            return true;
+        }
+    }
+
+    /* look for a chains like:
+       CompoundStmt
+         ReturnStmt
+           stuff
+             CXXThisExpr
+    */
+    childStmt = *(*compoundStmt->child_begin())->child_begin();
+    while (1) {
+        if (dyn_cast<CallExpr>( childStmt ) != nullptr)
+            return true;
+        if (dyn_cast<CXXNewExpr>( childStmt ) != nullptr)
+            return true;
+        if (dyn_cast<CXXConstructExpr>( childStmt ) != nullptr)
+            return true;
+        if (dyn_cast<ConditionalOperator>( childStmt ) != nullptr)
+            return true;
+        if (dyn_cast<BinaryOperator>( childStmt ) != nullptr)
+            return true;
+        // exclude methods that return fields on incomplete types .e.g the pImpl pattern
+        const MemberExpr* memberExpr = dyn_cast<MemberExpr>( childStmt );
+        if (memberExpr != nullptr && memberExpr->getMemberDecl()) {
+            const FieldDecl* fieldDecl = dyn_cast<FieldDecl>(memberExpr->getMemberDecl());
+            if (fieldDecl != nullptr)
+            {
+                // yes, a little bit of a hack. However, it is quite hard to determine if the method
+                // in question is accessing a field via a pImpl pattern.
+                if (fieldDecl->getType()->isIncompleteType())
+                    return true;
+                if (fieldDecl->getNameAsString().find("Impl") != std::string::npos)
+                    return true;
+                if (fieldDecl->getNameAsString().find("pImp") != std::string::npos)
+                    return true;
+                // somewhere in VCL
+                if (fieldDecl->getNameAsString().find("mpGlobalSyncData") != std::string::npos)
+                    return true;
+                std::string s = fieldDecl->getType().getAsString();
+                if (s.find("Impl") != std::string::npos || s.find("pImp") != std::string::npos || s.find("Internal") != std::string::npos)
+                    return true;
+            }
+        }
+        if (dyn_cast<CXXThisExpr>( childStmt ) != nullptr) {
+            if (!rewrite(functionDecl))
+            {
+                report(
+                    DiagnosticsEngine::Warning,
+                    "inlinesimpleaccessmethods",
+                    functionDecl->getSourceRange().getBegin())
+                  << functionDecl->getSourceRange();
+                // display the location of the class member declaration so I don't have to search for it by hand
+                report(
+                    DiagnosticsEngine::Note,
+                    "inlinesimpleaccessmethods",
+                    functionDecl->getCanonicalDecl()->getSourceRange().getBegin())
+                  << functionDecl->getCanonicalDecl()->getSourceRange();
+                }
+             return true;
+        }
+        if ( childStmt->children().begin() == childStmt->children().end() )
+            return true;
+        childStmt = *childStmt->child_begin();
+    }
+    return true;
+}
+
+static std::string ReplaceString(std::string subject, const std::string& search,
+                          const std::string& replace) {
+    size_t pos = 0;
+    while ((pos = subject.find(search, pos)) != std::string::npos) {
+         subject.replace(pos, search.length(), replace);
+         pos += replace.length();
+    }
+    return subject;
+}
+
+bool InlineSimpleMemberFunctions::rewrite(const CXXMethodDecl * functionDecl) {
+    if (rewriter == nullptr) {
+        return false;
+    }
+    // Only rewrite declarations in include files if a
+    // definition is also seen, to avoid compilation of a
+    // definition (in a main file only processed later) to fail
+    // with a "mismatch" error before the rewriter had a chance
+    // to act upon the definition.
+    if (!compiler.getSourceManager().isInMainFile(
+            compiler.getSourceManager().getSpellingLoc(
+                functionDecl->getNameInfo().getLoc())))
+    {
+        return false;
+    }
+
+    const char *p1, *p2;
+
+    // get the function body contents
+    p1 = compiler.getSourceManager().getCharacterData( functionDecl->getBody()->getBeginLoc() );
+    p2 = compiler.getSourceManager().getCharacterData( functionDecl->getBody()->getEndLoc() );
+    std::string s1( p1, p2 - p1 + 1);
+
+    /* we can't safely move around stuff containing comments, we mess up the resulting code */
+    if ( s1.find("/*") != std::string::npos || s1.find("//") != std::string::npos ) {
+        return false;
+    }
+
+    // strip linefeeds and any double-spaces, so we have a max of one space between tokens
+    s1 = ReplaceString(s1, "\r", "");
+    s1 = ReplaceString(s1, "\n", "");
+    s1 = ReplaceString(s1, "\t", " ");
+    s1 = ReplaceString(s1, "  ", " ");
+    s1 = ReplaceString(s1, "  ", " ");
+    s1 = ReplaceString(s1, "  ", " ");
+    s1 = " " + s1;
+
+    // scan from the end of the function's body through the trailing whitespace, so we can do a nice clean remove
+// commented out because for some reason it will sometimes chomp an extra token
+//    SourceLocation endOfRemoveLoc = functionDecl->getBody()->getLocEnd();
+//    for (;;) {
+//        endOfRemoveLoc = endOfRemoveLoc.getLocWithOffset(1);
+//        p1 = compiler.getSourceManager().getCharacterData( endOfRemoveLoc );
+//        if (*p1 != ' ' && *p1 != '\r' && *p1 != '\n' && *p1 != '\t')
+//            break;
+//    }
+
+    // remove the function's out of line body and declaration
+    RewriteOptions opts;
+    opts.RemoveLineIfEmpty = true;
+    if (!removeText(SourceRange(functionDecl->getBeginLoc(), functionDecl->getBody()->getEndLoc()), opts)) {
+        return false;
+    }
+
+    // scan forward until we find the semicolon
+    const FunctionDecl * canonicalDecl = functionDecl->getCanonicalDecl();
+    p1 = compiler.getSourceManager().getCharacterData( canonicalDecl->getEndLoc() );
+    p2 = ++p1;
+    while (*p2 != 0 && *p2 != ';') p2++;
+
+    // insert the function body into the inline function definition (i.e. the one inside the class definition)
+    return replaceText(canonicalDecl->getEndLoc().getLocWithOffset(p2 - p1 + 1), 1, s1);
+}
+
+loplugin::Plugin::Registration< InlineSimpleMemberFunctions > X("inlinesimplememberfunctions");
+
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */