1 files changed, 137 insertions, 0 deletions
diff --git a/compilerplugins/clang/unusedfieldsremove.cxx b/compilerplugins/clang/unusedfieldsremove.cxx
new file mode 100644
index 000000000..61df036f2
--- /dev/null
+++ b/compilerplugins/clang/unusedfieldsremove.cxx
@@ -0,0 +1,137 @@
+/* -*- 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/.
+ */
+
+#if !defined _WIN32 //TODO, #include <sys/mman.h>
+
+#include <cassert>
+#include <string>
+#include <iostream>
+#include "config_clang.h"
+#include "plugin.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 "unusedfields" clang plugin.
+*/
+
+namespace {
+
+class UnusedFieldsRemove:
+    public loplugin::FilteringRewritePlugin<UnusedFieldsRemove>
+{
+public:
+    explicit UnusedFieldsRemove(loplugin::InstantiationData const & data);
+    ~UnusedFieldsRemove();
+
+    virtual void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
+
+    bool VisitFieldDecl( const FieldDecl* 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;
+};
+
+size_t getFilesize(const char* filename)
+{
+    struct stat st;
+    stat(filename, &st);
+    return st.st_size;
+}
+
+UnusedFieldsRemove::UnusedFieldsRemove(loplugin::InstantiationData const & data): FilteringRewritePlugin(data)
+{
+    static const char sInputFile[] = SRCDIR "/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, mmapFD, 0));
+    assert(mmappedData != NULL);
+}
+
+UnusedFieldsRemove::~UnusedFieldsRemove()
+{
+    //Cleanup
+    int rc = munmap(mmappedData, mmapFilesize);
+    assert(rc == 0);
+    (void)rc;
+    close(mmapFD);
+}
+
+std::string niceName(const FieldDecl* fieldDecl)
+{
+    return fieldDecl->getParent()->getQualifiedNameAsString() + " " +
+        fieldDecl->getNameAsString();
+}
+
+bool UnusedFieldsRemove::VisitFieldDecl( const FieldDecl* fieldDecl )
+{
+    if (rewriter == nullptr) {
+        return true;
+    }
+    if (ignoreLocation(fieldDecl)) {
+        return true;
+    }
+    // ignore stuff that forms part of the stable URE interface
+    if (isInUnoIncludeFile(compiler.getSourceManager().getSpellingLoc(
+                              fieldDecl->getCanonicalDecl()->getLocation()))) {
+        return true;
+    }
+
+    // don't mess with templates
+/*    if (isa<CXXRecordDecl>(fieldDecl->getParent())) {
+        if (dyn_cast<CXXRecordDecl>(fieldDecl->getParent())->getDescribedClassTemplate() != nullptr) {
+            return true;
+        }
+    }
+*/
+    std::string aNiceName = " " + niceName(fieldDecl) + "\n";
+    const char *aNiceNameStr = aNiceName.c_str();
+    char* found = std::search(mmappedData, mmappedData + mmapFilesize, aNiceNameStr, aNiceNameStr + strlen(aNiceNameStr));
+    if(!(found < mmappedData + mmapFilesize)) {
+        return true;
+    }
+    SourceRange replaceRange(fieldDecl->getSourceRange());
+    // sometimes the declaration has a semicolon just after it, and it's much neater to remove that too.
+    if (rewriter->getRewrittenText(SourceRange(replaceRange.getEnd(), replaceRange.getEnd().getLocWithOffset(1))) == ";") {
+        replaceRange.setEnd(replaceRange.getEnd().getLocWithOffset(1));
+    }
+    // remove leading spaces
+    while (rewriter->getRewrittenText(SourceRange(replaceRange.getBegin().getLocWithOffset(-1), replaceRange.getBegin())) == " ")
+    {
+        replaceRange.setBegin(replaceRange.getBegin().getLocWithOffset(-1));
+    }
+    if (!replaceText(replaceRange, "")) {
+        report(
+            DiagnosticsEngine::Warning,
+            "Could not remove unused field (" + niceName(fieldDecl) + ")",
+            fieldDecl->getBeginLoc())
+          << fieldDecl->getSourceRange();
+    }
+    return true;
+}
+
+
+loplugin::Plugin::Registration< UnusedFieldsRemove > X("unusedfieldsremove", false);
+
+}
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */