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 loplugin::FilteringRewritePlugin<UnusedMethodsRemove>
  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): 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 UnusedMethodsRemove::~UnusedMethodsRemove()
  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 CXXMethodDecl* functionDecl)
  78 {
  79     std::string s =
  80         functionDecl->getReturnType().getCanonicalType().getAsString()
  81         + " " + functionDecl->getParent()->getQualifiedNameAsString()
  82         + "::" + functionDecl->getNameAsString()
  83         + "(";
  84     bool bFirst = true;
  85     for (const ParmVarDecl *pParmVarDecl : functionDecl->parameters()) {
  86         if (bFirst)
  87             bFirst = false;
  88         else
  89             s += ",";
  90         s += pParmVarDecl->getType().getCanonicalType().getAsString();
  91     }
  92     s += ")";
  93     if (functionDecl->isConst()) {
  94         s += " const";
  95     }
  96     return s;
  97 }
  98
  99 bool UnusedMethodsRemove::VisitCXXMethodDecl( const CXXMethodDecl* functionDecl )
 100 {
 101     if (rewriter == nullptr) {
 102         return true;
 103     }
 104     if (ignoreLocation(functionDecl)) {
 105         return true;
 106     }
 107     // ignore stuff that forms part of the stable URE interface
 108     if (isInUnoIncludeFile(functionDecl)) {
 109         return true;
 110     }
 111
 112     // don't mess with templates
 113     if (functionDecl->getParent()->getDescribedClassTemplate() != nullptr) {
 114         return true;
 115     }
 116     if (functionDecl->getTemplatedKind() != FunctionDecl::TK_NonTemplate) {
 117         return true;
 118     }
 119
 120     std::string aNiceName = "\n" + niceName(functionDecl) + "\n";
 121     const char *aNiceNameStr = aNiceName.c_str();
 122     char* found = std::search(mmappedData, mmappedData + mmapFilesize, aNiceNameStr, aNiceNameStr + strlen(aNiceNameStr));
 123     if(!(found < mmappedData + mmapFilesize)) {
 124         return true;
 125     }
 126     SourceRange replaceRange(functionDecl->getSourceRange());
 127     // sometimes the declaration has a semicolon just after it, and it's much neater to remove that too.
 128     if (rewriter->getRewrittenText(SourceRange(replaceRange.getEnd(), replaceRange.getEnd().getLocWithOffset(1))) == ";") {
 129         replaceRange.setEnd(replaceRange.getEnd().getLocWithOffset(1));
 130     }
 131     // remove leading spaces
 132     while (rewriter->getRewrittenText(SourceRange(replaceRange.getBegin().getLocWithOffset(-1), replaceRange.getBegin())) == " ")
 133     {
 134         replaceRange.setBegin(replaceRange.getBegin().getLocWithOffset(-1));
 135     }
 136     if (!replaceText(replaceRange, "")) {
 137         report(
 138             DiagnosticsEngine::Warning,
 139             "Could not remove unused method (" + niceName(functionDecl) + ")",
 140             compat::getBeginLoc(functionDecl))
 141           << functionDecl->getSourceRange();
 142     }
 143     return true;
 144 }
 145
 146
 147 loplugin::Plugin::Registration< UnusedMethodsRemove > X("unusedmethodsremove", false);
 148
 149 }
 150
 151 #endif
 152
 153 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */