compilerplugins/clang/unusedfieldsremove.cxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  */
   9
  10 #if !defined _WIN32 //TODO, #include <sys/mman.h>
  11
  12 #include <cassert>
  13 #include <string>
  14 #include <iostream>
  15 #include "plugin.hxx"
  16 #include <sys/mman.h>
  17 #include <sys/types.h>
  18 #include <fcntl.h>
  19 #include <unistd.h>
  20 #include <sys/stat.h>
  21 #include <assert.h>
  22 #include <cstring>
  23
  24 /**
  25   This is intended to be run as the second stage of the "unusedfields" clang plugin.
  26 */
  27
  28 namespace {
  29
  30 class UnusedFieldsRemove:
  31     public loplugin::FilteringRewritePlugin<UnusedFieldsRemove>
  32 {
  33 public:
  34     explicit UnusedFieldsRemove(loplugin::InstantiationData const & data);
  35     ~UnusedFieldsRemove();
  36
  37     virtual void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
  38
  39     bool VisitFieldDecl( const FieldDecl* var );
  40 private:
  41     // I use a brute-force approach - mmap the results file and do a linear search on it
  42     // It works surprisingly well, because the file is small enough to fit into L2 cache on modern CPU's
  43     size_t mmapFilesize;
  44     int mmapFD;
  45     char* mmappedData;
  46 };
  47
  48 size_t getFilesize(const char* filename)
  49 {
  50     struct stat st;
  51     stat(filename, &st);
  52     return st.st_size;
  53 }
  54
  55 UnusedFieldsRemove::UnusedFieldsRemove(loplugin::InstantiationData const & data): FilteringRewritePlugin(data)
  56 {
  57     static const char sInputFile[] = SRCDIR "/result.txt";
  58     mmapFilesize = getFilesize(sInputFile);
  59     //Open file
  60     mmapFD = open(sInputFile, O_RDONLY, 0);
  61     assert(mmapFD != -1);
  62     //Execute mmap
  63     mmappedData = static_cast<char*>(mmap(NULL, mmapFilesize, PROT_READ, MAP_PRIVATE, mmapFD, 0));
  64     assert(mmappedData != NULL);
  65 }
  66
  67 UnusedFieldsRemove::~UnusedFieldsRemove()
  68 {
  69     //Cleanup
  70     int rc = munmap(mmappedData, mmapFilesize);
  71     assert(rc == 0);
  72     (void)rc;
  73     close(mmapFD);
  74 }
  75
  76 std::string niceName(const FieldDecl* fieldDecl)
  77 {
  78     return fieldDecl->getParent()->getQualifiedNameAsString() + " " +
  79         fieldDecl->getNameAsString();
  80 }
  81
  82 bool UnusedFieldsRemove::VisitFieldDecl( const FieldDecl* fieldDecl )
  83 {
  84     if (rewriter == nullptr) {
  85         return true;
  86     }
  87     if (ignoreLocation(fieldDecl)) {
  88         return true;
  89     }
  90     // ignore stuff that forms part of the stable URE interface
  91     if (isInUnoIncludeFile(compiler.getSourceManager().getSpellingLoc(
  92                               fieldDecl->getCanonicalDecl()->getLocation()))) {
  93         return true;
  94     }
  95
  96     // don't mess with templates
  97 /*    if (isa<CXXRecordDecl>(fieldDecl->getParent())) {
  98         if (dyn_cast<CXXRecordDecl>(fieldDecl->getParent())->getDescribedClassTemplate() != nullptr) {
  99             return true;
 100         }
 101     }
 102 */
 103     std::string aNiceName = " " + niceName(fieldDecl) + "\n";
 104     const char *aNiceNameStr = aNiceName.c_str();
 105     char* found = std::search(mmappedData, mmappedData + mmapFilesize, aNiceNameStr, aNiceNameStr + strlen(aNiceNameStr));
 106     if(!(found < mmappedData + mmapFilesize)) {
 107         return true;
 108     }
 109     SourceRange replaceRange(fieldDecl->getSourceRange());
 110     // sometimes the declaration has a semicolon just after it, and it's much neater to remove that too.
 111     if (rewriter->getRewrittenText(SourceRange(replaceRange.getEnd(), replaceRange.getEnd().getLocWithOffset(1))) == ";") {
 112         replaceRange.setEnd(replaceRange.getEnd().getLocWithOffset(1));
 113     }
 114     // remove leading spaces
 115     while (rewriter->getRewrittenText(SourceRange(replaceRange.getBegin().getLocWithOffset(-1), replaceRange.getBegin())) == " ")
 116     {
 117         replaceRange.setBegin(replaceRange.getBegin().getLocWithOffset(-1));
 118     }
 119     if (!replaceText(replaceRange, "")) {
 120         report(
 121             DiagnosticsEngine::Warning,
 122             "Could not remove unused field (" + niceName(fieldDecl) + ")",
 123             compat::getBeginLoc(fieldDecl))
 124           << fieldDecl->getSourceRange();
 125     }
 126     return true;
 127 }
 128
 129
 130 loplugin::Plugin::Registration< UnusedFieldsRemove > X("unusedfieldsremove", false);
 131
 132 }
 133
 134 #endif
 135
 136 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */