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 #if !defined _WIN32 //TODO, #include <sys/mman.h>
  11
  12 #include <cassert>
  13 #include <string>
  14 #include <iostream>
  15 #include "plugin.hxx"
  16 #include "compat.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 "unusedmethods" clang plugin.
  27 */
  28
  29 namespace {
  30
  31 class UnusedMethodsRemove:
  32     public RecursiveASTVisitor<UnusedMethodsRemove>, public loplugin::RewritePlugin
  33 {
  34 public:
  35     explicit UnusedMethodsRemove(loplugin::InstantiationData const & data);
  36     ~UnusedMethodsRemove();
  37
  38     virtual void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
  39
  40     bool VisitCXXMethodDecl( const CXXMethodDecl* 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 UnusedMethodsRemove::UnusedMethodsRemove(loplugin::InstantiationData const & data): RewritePlugin(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 UnusedMethodsRemove::~UnusedMethodsRemove()
  69 {
  70     //Cleanup
  71     int rc = munmap(mmappedData, mmapFilesize);
  72     assert(rc == 0);
  73     close(mmapFD);
  74 }
  75
  76 std::string niceName(const CXXMethodDecl* functionDecl)
  77 {
  78     std::string s =
  79         functionDecl->getReturnType().getCanonicalType().getAsString()
  80         + " " + functionDecl->getParent()->getQualifiedNameAsString()
  81         + "::" + functionDecl->getNameAsString()
  82         + "(";
  83     bool bFirst = true;
  84     for (const ParmVarDecl *pParmVarDecl : compat::parameters(*functionDecl)) {
  85         if (bFirst)
  86             bFirst = false;
  87         else
  88             s += ",";
  89         s += pParmVarDecl->getType().getCanonicalType().getAsString();
  90     }
  91     s += ")";
  92     if (functionDecl->isConst()) {
  93         s += " const";
  94     }
  95     return s;
  96 }
  97
  98 bool UnusedMethodsRemove::VisitCXXMethodDecl( const CXXMethodDecl* functionDecl )
  99 {
 100     if (rewriter == nullptr) {
 101         return true;
 102     }
 103     if (ignoreLocation(functionDecl)) {
 104         return true;
 105     }
 106     // ignore stuff that forms part of the stable URE interface
 107     if (isInUnoIncludeFile(functionDecl)) {
 108         return true;
 109     }
 110
 111     // don't mess with templates
 112     if (functionDecl->getParent()->getDescribedClassTemplate() != nullptr) {
 113         return true;
 114     }
 115     if (functionDecl->getTemplatedKind() != FunctionDecl::TK_NonTemplate) {
 116         return true;
 117     }
 118
 119     std::string aNiceName = "\n" + niceName(functionDecl) + "\n";
 120     const char *aNiceNameStr = aNiceName.c_str();
 121     char* found = std::search(mmappedData, mmappedData + mmapFilesize, aNiceNameStr, aNiceNameStr + strlen(aNiceNameStr));
 122     if(!(found < mmappedData + mmapFilesize)) {
 123         return true;
 124     }
 125     SourceRange replaceRange(functionDecl->getSourceRange());
 126     // sometimes the declaration has a semicolon just after it, and it's much neater to remove that too.
 127     if (rewriter->getRewrittenText(SourceRange(replaceRange.getEnd(), replaceRange.getEnd().getLocWithOffset(1))) == ";") {
 128         replaceRange.setEnd(replaceRange.getEnd().getLocWithOffset(1));
 129     }
 130     // remove leading spaces
 131     while (rewriter->getRewrittenText(SourceRange(replaceRange.getBegin().getLocWithOffset(-1), replaceRange.getBegin())) == " ")
 132     {
 133         replaceRange.setBegin(replaceRange.getBegin().getLocWithOffset(-1));
 134     }
 135     if (!replaceText(replaceRange, "")) {
 136         report(
 137             DiagnosticsEngine::Warning,
 138             "Could not remove unused method (" + niceName(functionDecl) + ")",
 139             functionDecl->getLocStart())
 140           << functionDecl->getSourceRange();
 141     }
 142     return true;
 143 }
 144
 145
 146 loplugin::Plugin::Registration< UnusedMethodsRemove > X("unusedmethodsremove", false);
 147
 148 }
 149
 150 #endif
 151
 152 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */