new loplugin: unusedmethods

Change-Id: I72574e354aadf357d6d8181a514efb4783e79e28

compilerplugins/clang/unusedmethodsremove.cxx

@@ -0,0 +1,145 @@
+/* -*- 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 <string>
+#include <iostream>
+#include "plugin.hxx"
+#include "compat.hxx"
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <assert.h>
+#include <cstring>
+
+/**
+  This is intended to be run as the second stage of the "unusedmethods" clang plugin.
+*/
+
+namespace {
+
+class UnusedMethodsRemove:
+    public RecursiveASTVisitor<UnusedMethodsRemove>, public loplugin::RewritePlugin
+{
+public:
+    explicit UnusedMethodsRemove(InstantiationData const & data);
+    ~UnusedMethodsRemove();
+
+    virtual void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
+
+    bool VisitCXXMethodDecl( const CXXMethodDecl* var );
+private:
+    // I use a brute-force approach - mmap the results file and do a linear search on it
+    // It works surprisingly well, because the file is small enough to fit into L2 cache on modern CPU's
+    size_t mmapFilesize;
+    int mmapFD;
+    char* mmappedData;
+};
+
+static size_t getFilesize(const char* filename)
+{
+    struct stat st;
+    stat(filename, &st);
+    return st.st_size;
+}
+
+UnusedMethodsRemove::UnusedMethodsRemove(InstantiationData const & data): RewritePlugin(data)
+{
+    static const char sInputFile[] = "/home/noel/libo4/result.txt";
+    mmapFilesize = getFilesize(sInputFile);
+    //Open file
+    mmapFD = open(sInputFile, O_RDONLY, 0);
+    assert(mmapFD != -1);
+    //Execute mmap
+    mmappedData = static_cast<char*>(mmap(NULL, mmapFilesize, PROT_READ, MAP_PRIVATE | MAP_POPULATE, mmapFD, 0));
+    assert(mmappedData != NULL);
+}
+
+UnusedMethodsRemove::~UnusedMethodsRemove()
+{
+    //Cleanup
+    int rc = munmap(mmappedData, mmapFilesize);
+    assert(rc == 0);
+    close(mmapFD);
+}
+
+static std::string niceName(const CXXMethodDecl* functionDecl)
+{
+    std::string s =
+        compat::getReturnType(*functionDecl).getCanonicalType().getAsString()
+        + " " + functionDecl->getParent()->getQualifiedNameAsString()
+        + "::" + functionDecl->getNameAsString()
+        + "(";
+    bool bFirst = true;
+    for (const ParmVarDecl *pParmVarDecl : functionDecl->params()) {
+        if (bFirst)
+            bFirst = false;
+        else
+            s += ",";
+        s += pParmVarDecl->getType().getCanonicalType().getAsString();
+    }
+    s += ")";
+    if (functionDecl->isConst()) {
+        s += " const";
+    }
+    return s;
+}
+
+bool UnusedMethodsRemove::VisitCXXMethodDecl( const CXXMethodDecl* functionDecl )
+{
+    if (rewriter == nullptr) {
+        return true;
+    }
+    if (ignoreLocation(functionDecl)) {
+        return true;
+    }
+    // ignore stuff that forms part of the stable URE interface
+    if (isInUnoIncludeFile(compiler.getSourceManager().getSpellingLoc(
+                              functionDecl->getCanonicalDecl()->getNameInfo().getLoc()))) {
+        return true;
+    }
+
+    // don't mess with templates
+    if (functionDecl->getParent()->getDescribedClassTemplate() != nullptr) {
+        return true;
+    }
+    if (functionDecl->getTemplatedKind() != FunctionDecl::TK_NonTemplate) {
+        return true;
+    }
+
+    std::string aNiceName = "\n" + niceName(functionDecl) + "\n";
+    const char *aNiceNameStr = aNiceName.c_str();
+    char* found = std::search(mmappedData, mmappedData + mmapFilesize, aNiceNameStr, aNiceNameStr + strlen(aNiceNameStr));
+    if(!(found < mmappedData + mmapFilesize)) {
+        return true;
+    }
+    // sometimes the declaration has a semicolon just after it, and it's much neater to remove that too.
+    SourceRange replaceRange(functionDecl->getSourceRange());
+    if (rewriter->getRewrittenText(SourceRange(replaceRange.getEnd(), replaceRange.getEnd().getLocWithOffset(1))) == ";") {
+        replaceRange.setEnd(replaceRange.getEnd().getLocWithOffset(1));
+    }
+    if (!replaceText(replaceRange, "")) {
+        report(
+            DiagnosticsEngine::Warning,
+            "Could not remove unused method (" + niceName(functionDecl) + ")",
+            functionDecl->getLocStart())
+          << functionDecl->getSourceRange();
+    }
+    return true;
+}
+
+
+
+loplugin::Plugin::Registration< UnusedMethodsRemove > X("unusedmethodsremove", false);
+
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */