compilerplugins/clang/unusedmethodsremove.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 #include <cassert>
  11 #include <string>
  12 #include <iostream>
  13 #include "plugin.hxx"
  14 #include "compat.hxx"
  15 #include <sys/mman.h>
  16 #include <sys/types.h>
  17 #include <fcntl.h>
  18 #include <unistd.h>
  19 #include <sys/stat.h>
  20 #include <assert.h>
  21 #include <cstring>
  22
  23 /**
  24   This is intended to be run as the second stage of the "unusedmethods" clang plugin.
  25 */
  26
  27 namespace {
  28
  29 class UnusedMethodsRemove:
  30     public RecursiveASTVisitor<UnusedMethodsRemove>, public loplugin::RewritePlugin
  31 {
  32 public:
  33     explicit UnusedMethodsRemove(InstantiationData const & data);
  34     ~UnusedMethodsRemove();
  35
  36     virtual void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
  37
  38     bool VisitCXXMethodDecl( const CXXMethodDecl* var );
  39 private:
  40     // I use a brute-force approach - mmap the results file and do a linear search on it
  41     // It works surprisingly well, because the file is small enough to fit into L2 cache on modern CPU's
  42     size_t mmapFilesize;
  43     int mmapFD;
  44     char* mmappedData;
  45 };
  46
  47 size_t getFilesize(const char* filename)
  48 {
  49     struct stat st;
  50     stat(filename, &st);
  51     return st.st_size;
  52 }
  53
  54 UnusedMethodsRemove::UnusedMethodsRemove(InstantiationData const & data): RewritePlugin(data)
  55 {
  56     static const char sInputFile[] = SRCDIR "/result.txt";
  57     mmapFilesize = getFilesize(sInputFile);
  58     //Open file
  59     mmapFD = open(sInputFile, O_RDONLY, 0);
  60     assert(mmapFD != -1);
  61     //Execute mmap
  62     mmappedData = static_cast<char*>(mmap(NULL, mmapFilesize, PROT_READ, MAP_PRIVATE, mmapFD, 0));
  63     assert(mmappedData != NULL);
  64 }
  65
  66 UnusedMethodsRemove::~UnusedMethodsRemove()
  67 {
  68     //Cleanup
  69     int rc = munmap(mmappedData, mmapFilesize);
  70     assert(rc == 0);
  71     close(mmapFD);
  72 }
  73
  74 std::string niceName(const CXXMethodDecl* functionDecl)
  75 {
  76     std::string s =
  77         compat::getReturnType(*functionDecl).getCanonicalType().getAsString()
  78         + " " + functionDecl->getParent()->getQualifiedNameAsString()
  79         + "::" + functionDecl->getNameAsString()
  80         + "(";
  81     bool bFirst = true;
  82     for (const ParmVarDecl *pParmVarDecl : compat::parameters(*functionDecl)) {
  83         if (bFirst)
  84             bFirst = false;
  85         else
  86             s += ",";
  87         s += pParmVarDecl->getType().getCanonicalType().getAsString();
  88     }
  89     s += ")";
  90     if (functionDecl->isConst()) {
  91         s += " const";
  92     }
  93     return s;
  94 }
  95
  96 bool UnusedMethodsRemove::VisitCXXMethodDecl( const CXXMethodDecl* functionDecl )
  97 {
  98     if (rewriter == nullptr) {
  99         return true;
 100     }
 101     if (ignoreLocation(functionDecl)) {
 102         return true;
 103     }
 104     // ignore stuff that forms part of the stable URE interface
 105     if (isInUnoIncludeFile(functionDecl)) {
 106         return true;
 107     }
 108
 109     // don't mess with templates
 110     if (functionDecl->getParent()->getDescribedClassTemplate() != nullptr) {
 111         return true;
 112     }
 113     if (functionDecl->getTemplatedKind() != FunctionDecl::TK_NonTemplate) {
 114         return true;
 115     }
 116
 117     std::string aNiceName = "\n" + niceName(functionDecl) + "\n";
 118     const char *aNiceNameStr = aNiceName.c_str();
 119     char* found = std::search(mmappedData, mmappedData + mmapFilesize, aNiceNameStr, aNiceNameStr + strlen(aNiceNameStr));
 120     if(!(found < mmappedData + mmapFilesize)) {
 121         return true;
 122     }
 123     SourceRange replaceRange(functionDecl->getSourceRange());
 124     // sometimes the declaration has a semicolon just after it, and it's much neater to remove that too.
 125     if (rewriter->getRewrittenText(SourceRange(replaceRange.getEnd(), replaceRange.getEnd().getLocWithOffset(1))) == ";") {
 126         replaceRange.setEnd(replaceRange.getEnd().getLocWithOffset(1));
 127     }
 128     // remove leading spaces
 129     while (rewriter->getRewrittenText(SourceRange(replaceRange.getBegin().getLocWithOffset(-1), replaceRange.getBegin())) == " ")
 130     {
 131         replaceRange.setBegin(replaceRange.getBegin().getLocWithOffset(-1));
 132     }
 133     if (!replaceText(replaceRange, "")) {
 134         report(
 135             DiagnosticsEngine::Warning,
 136             "Could not remove unused method (" + niceName(functionDecl) + ")",
 137             functionDecl->getLocStart())
 138           << functionDecl->getSourceRange();
 139     }
 140     return true;
 141 }
 142
 143
 144 loplugin::Plugin::Registration< UnusedMethodsRemove > X("unusedmethodsremove", false);
 145
 146 }
 147
 148 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */