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