compilerplugins/clang/store/constfieldsrewrite.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 "check.hxx"
  17 #include "config_clang.h"
  18 #include <sys/mman.h>
  19 #include <sys/types.h>
  20 #include <fcntl.h>
  21 #include <unistd.h>
  22 #include <sys/stat.h>
  23 #include <assert.h>
  24 #include <cstring>
  25
  26 /**
  27   This is intended to be run as the second stage of the "constfields" clang plugin.
  28 */
  29
  30 namespace
  31 {
  32 class ConstFieldsRewrite : public RecursiveASTVisitor<ConstFieldsRewrite>,
  33                            public loplugin::RewritePlugin
  34 {
  35 public:
  36     explicit ConstFieldsRewrite(loplugin::InstantiationData const& data);
  37     ~ConstFieldsRewrite();
  38
  39     virtual void run() override
  40     {
  41         if (rewriter)
  42         {
  43             TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
  44         }
  45     }
  46
  47     bool VisitFieldDecl(const FieldDecl* var);
  48
  49 private:
  50     // I use a brute-force approach - mmap the results file and do a linear search on it
  51     // It works surprisingly well, because the file is small enough to fit into L2 cache on modern CPU's
  52     size_t mmapFilesize;
  53     int mmapFD;
  54     char* mmappedData;
  55 };
  56
  57 size_t getFilesize(const char* filename)
  58 {
  59     struct stat st;
  60     stat(filename, &st);
  61     return st.st_size;
  62 }
  63
  64 ConstFieldsRewrite::ConstFieldsRewrite(loplugin::InstantiationData const& data)
  65     : RewritePlugin(data)
  66 {
  67     static const char sInputFile[] = SRCDIR "/compilerplugins/clang/constfields.results";
  68     mmapFilesize = getFilesize(sInputFile);
  69     //Open file
  70     mmapFD = open(sInputFile, O_RDONLY, 0);
  71     assert(mmapFD != -1);
  72     //Execute mmap
  73     mmappedData = static_cast<char*>(mmap(NULL, mmapFilesize, PROT_READ, MAP_PRIVATE, mmapFD, 0));
  74     assert(mmappedData != NULL);
  75 }
  76
  77 ConstFieldsRewrite::~ConstFieldsRewrite()
  78 {
  79     //Cleanup
  80     int rc = munmap(mmappedData, mmapFilesize);
  81     assert(rc == 0);
  82     (void)rc;
  83     close(mmapFD);
  84 }
  85
  86 bool ConstFieldsRewrite::VisitFieldDecl(const FieldDecl* fieldDecl)
  87 {
  88     if (ignoreLocation(fieldDecl))
  89         return true;
  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     // in case we've already processed this field
  95     if (fieldDecl->getType().isConstQualified())
  96         return true;
  97     // TODO rewriting T& is a bit trickier
  98     if (loplugin::TypeCheck(fieldDecl->getType()).LvalueReference())
  99         return true;
 100
 101     const RecordDecl* recordDecl = fieldDecl->getParent();
 102     std::string parentClassName;
 103     if (const CXXRecordDecl* cxxRecordDecl = dyn_cast<CXXRecordDecl>(recordDecl))
 104     {
 105         if (cxxRecordDecl->getTemplateInstantiationPattern())
 106             cxxRecordDecl = cxxRecordDecl->getTemplateInstantiationPattern();
 107         parentClassName = cxxRecordDecl->getQualifiedNameAsString();
 108     }
 109     else
 110     {
 111         parentClassName = recordDecl->getQualifiedNameAsString();
 112     }
 113     // the extra spaces match the formatting in the results file, and help avoid false+
 114     std::string aNiceName = "    " + parentClassName + " " + fieldDecl->getNameAsString() + " "
 115                             + fieldDecl->getType().getAsString() + "\n";
 116
 117     // search mmap'ed file for field
 118     const char* aNiceNameStr = aNiceName.c_str();
 119     char* found = std::search(mmappedData, mmappedData + mmapFilesize, aNiceNameStr,
 120                               aNiceNameStr + aNiceName.size());
 121     if (!(found < mmappedData + mmapFilesize))
 122         return true;
 123
 124     SourceManager& SM = compiler.getSourceManager();
 125     auto endLoc = fieldDecl->getTypeSourceInfo()->getTypeLoc().getEndLoc();
 126     endLoc = endLoc.getLocWithOffset(Lexer::MeasureTokenLength(endLoc, SM, compiler.getLangOpts()));
 127
 128     // Calculate how much space is available after the type declaration that we can use to
 129     // overwrite with the " const". This reduces the amount of formatting fixups I need to do.
 130     char const* p1 = SM.getCharacterData(endLoc);
 131     bool success = false;
 132     if (*p1 != ' ')
 133     {
 134         // Sometimes there is no space at all e.g. in
 135         //     FastTokenHandlerBase *mpTokenHandler;
 136         // between the "*" and the "mpTokenHandler", so add an extra space.
 137         success = insertText(endLoc, " const ");
 138     }
 139     else
 140     {
 141         int spaceAvailable = 1;
 142         ++p1;
 143         for (; spaceAvailable < 6; ++spaceAvailable)
 144         {
 145             if (*p1 != ' ')
 146                 break;
 147             ++p1;
 148         }
 149         if (spaceAvailable < 6)
 150             success = replaceText(endLoc, spaceAvailable - 1, " const");
 151         else
 152             success = replaceText(endLoc, spaceAvailable, " const");
 153     }
 154
 155     if (!success)
 156     {
 157         report(DiagnosticsEngine::Warning, "Could not mark field as const",
 158                fieldDecl->getBeginLoc())
 159             << fieldDecl->getSourceRange();
 160     }
 161     return true;
 162 }
 163
 164 loplugin::Plugin::Registration<ConstFieldsRewrite> X("constfieldsrewrite", false);
 165 }
 166
 167 #endif
 168
 169 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */