The Tor Browser: gfx/angle/src/compiler/preprocessor/MacroExpander.cpp@97036ab72558 (annotated)

gfx/angle/src/compiler/preprocessor/MacroExpander.cpp@97036ab72558 (annotated)

gfx/angle/src/compiler/preprocessor/MacroExpander.cpp

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 //
 // Copyright (c) 2011 The ANGLE Project Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 #include "MacroExpander.h"
 #include <algorithm>
 #include <sstream>
 #include "DiagnosticsBase.h"
 #include "Token.h"
 namespace pp
 {
 class TokenLexer : public Lexer
 {
  public:
     typedef std::vector<Token> TokenVector;
     TokenLexer(TokenVector* tokens)
     {
         tokens->swap(mTokens);
         mIter = mTokens.begin();
     }
     virtual void lex(Token* token)
     {
         if (mIter == mTokens.end())
         {
             token->reset();
             token->type = Token::LAST;
         }
         else
         {
             *token = *mIter++;
         }
     }
  private:
     PP_DISALLOW_COPY_AND_ASSIGN(TokenLexer);
     TokenVector mTokens;
     TokenVector::const_iterator mIter;
 };
 MacroExpander::MacroExpander(Lexer* lexer,
                              MacroSet* macroSet,
                              Diagnostics* diagnostics) :
     mLexer(lexer),
     mMacroSet(macroSet),
     mDiagnostics(diagnostics)
 {
 }
 MacroExpander::~MacroExpander()
 {
     for (std::size_t i = 0; i < mContextStack.size(); ++i)
     {
         delete mContextStack[i];
     }
 }
 void MacroExpander::lex(Token* token)
 {
     while (true)
     {
         getToken(token);
         if (token->type != Token::IDENTIFIER)
             break;
         if (token->expansionDisabled())
             break;
         MacroSet::const_iterator iter = mMacroSet->find(token->text);
         if (iter == mMacroSet->end())
             break;
         const Macro& macro = iter->second;
         if (macro.disabled)
         {
             // If a particular token is not expanded, it is never expanded.
             token->setExpansionDisabled(true);
             break;
         }
         if ((macro.type == Macro::kTypeFunc) && !isNextTokenLeftParen())
         {
             // If the token immediately after the macro name is not a '(',
             // this macro should not be expanded.
             break;
         }
         pushMacro(macro, *token);
     }
 }
 void MacroExpander::getToken(Token* token)
 {
     if (mReserveToken.get())
     {
         *token = *mReserveToken;
         mReserveToken.reset();
         return;
     }
     // First pop all empty macro contexts.
     while (!mContextStack.empty() && mContextStack.back()->empty())
     {
         popMacro();
     }
     if (!mContextStack.empty())
     {
         *token = mContextStack.back()->get();
     }
     else
     {
         mLexer->lex(token);
     }
 }
 void MacroExpander::ungetToken(const Token& token)
 {
     if (!mContextStack.empty())
     {
         MacroContext* context = mContextStack.back();
         context->unget();
         assert(context->replacements[context->index] == token);
     }
     else
     {
         assert(!mReserveToken.get());
         mReserveToken.reset(new Token(token));
     }
 }
 bool MacroExpander::isNextTokenLeftParen()
 {
     Token token;
     getToken(&token);
     bool lparen = token.type == '(';
     ungetToken(token);
     return lparen;
 }
 bool MacroExpander::pushMacro(const Macro& macro, const Token& identifier)
 {
     assert(!macro.disabled);
     assert(!identifier.expansionDisabled());
     assert(identifier.type == Token::IDENTIFIER);
     assert(identifier.text == macro.name);
     std::vector<Token> replacements;
     if (!expandMacro(macro, identifier, &replacements))
         return false;
     // Macro is disabled for expansion until it is popped off the stack.
     macro.disabled = true;
     MacroContext* context = new MacroContext;
     context->macro = &macro;
     context->replacements.swap(replacements);
     mContextStack.push_back(context);
     return true;
 }
 void MacroExpander::popMacro()
 {
     assert(!mContextStack.empty());
     MacroContext* context = mContextStack.back();
     mContextStack.pop_back();
     assert(context->empty());
     assert(context->macro->disabled);
     context->macro->disabled = false;
     delete context;
 }
 bool MacroExpander::expandMacro(const Macro& macro,
                                 const Token& identifier,
                                 std::vector<Token>* replacements)
 {
     replacements->clear();
     if (macro.type == Macro::kTypeObj)
     {
         replacements->assign(macro.replacements.begin(),
                              macro.replacements.end());
         if (macro.predefined)
         {
             static const std::string kLine = "__LINE__";
             static const std::string kFile = "__FILE__";
             assert(replacements->size() == 1);
             Token& repl = replacements->front();
             if (macro.name == kLine)
             {
                 std::ostringstream stream;
                 stream << identifier.location.line;
                 repl.text = stream.str();
             }
             else if (macro.name == kFile)
             {
                 std::ostringstream stream;
                 stream << identifier.location.file;
                 repl.text = stream.str();
             }
         }
     }
     else
     {
         assert(macro.type == Macro::kTypeFunc);
         std::vector<MacroArg> args;
         args.reserve(macro.parameters.size());
         if (!collectMacroArgs(macro, identifier, &args))
             return false;
         replaceMacroParams(macro, args, replacements);
     }
     for (std::size_t i = 0; i < replacements->size(); ++i)
     {
         Token& repl = replacements->at(i);
         if (i == 0)
         {
             // The first token in the replacement list inherits the padding
             // properties of the identifier token.
             repl.setAtStartOfLine(identifier.atStartOfLine());
             repl.setHasLeadingSpace(identifier.hasLeadingSpace());
         }
         repl.location = identifier.location;
     }
     return true;
 }
 bool MacroExpander::collectMacroArgs(const Macro& macro,
                                      const Token& identifier,
                                      std::vector<MacroArg>* args)
 {
     Token token;
     getToken(&token);
     assert(token.type == '(');
     args->push_back(MacroArg());
     for (int openParens = 1; openParens != 0; )
     {
         getToken(&token);
         if (token.type == Token::LAST)
         {
             mDiagnostics->report(Diagnostics::MACRO_UNTERMINATED_INVOCATION,
                                  identifier.location, identifier.text);
             // Do not lose EOF token.
             ungetToken(token);
             return false;
         }
         bool isArg = false; // True if token is part of the current argument.
         switch (token.type)
         {
           case '(':
             ++openParens;
             isArg = true;
             break;
           case ')':
             --openParens;
             isArg = openParens != 0;
             break;
           case ',':
             // The individual arguments are separated by comma tokens, but
             // the comma tokens between matching inner parentheses do not
             // seperate arguments.
             if (openParens == 1) args->push_back(MacroArg());
             isArg = openParens != 1;
             break;
           default:
             isArg = true;
             break;
         }
         if (isArg)
         {
             MacroArg& arg = args->back();
             // Initial whitespace is not part of the argument.
             if (arg.empty()) token.setHasLeadingSpace(false);
             arg.push_back(token);
         }
     }
     const Macro::Parameters& params = macro.parameters;
     // If there is only one empty argument, it is equivalent to no argument.
     if (params.empty() && (args->size() == 1) && args->front().empty())
     {
         args->clear();
     }
     // Validate the number of arguments.
     if (args->size() != params.size())
     {
         Diagnostics::ID id = args->size() < macro.parameters.size() ?
             Diagnostics::MACRO_TOO_FEW_ARGS :
             Diagnostics::MACRO_TOO_MANY_ARGS;
         mDiagnostics->report(id, identifier.location, identifier.text);
         return false;
     }
     // Pre-expand each argument before substitution.
     // This step expands each argument individually before they are
     // inserted into the macro body.
     for (std::size_t i = 0; i < args->size(); ++i)
     {
         MacroArg& arg = args->at(i);
         TokenLexer lexer(&arg);
         MacroExpander expander(&lexer, mMacroSet, mDiagnostics);
         arg.clear();
         expander.lex(&token);
         while (token.type != Token::LAST)
         {
             arg.push_back(token);
             expander.lex(&token);
         }
     }
     return true;
 }
 void MacroExpander::replaceMacroParams(const Macro& macro,
                                        const std::vector<MacroArg>& args,
                                        std::vector<Token>* replacements)
 {
     for (std::size_t i = 0; i < macro.replacements.size(); ++i)
     {
         const Token& repl = macro.replacements[i];
         if (repl.type != Token::IDENTIFIER)
         {
             replacements->push_back(repl);
             continue;
         }
         // TODO(alokp): Optimize this.
         // There is no need to search for macro params every time.
         // The param index can be cached with the replacement token.
         Macro::Parameters::const_iterator iter = std::find(
             macro.parameters.begin(), macro.parameters.end(), repl.text);
         if (iter == macro.parameters.end())
         {
             replacements->push_back(repl);
             continue;
         }
         std::size_t iArg = std::distance(macro.parameters.begin(), iter);
         const MacroArg& arg = args[iArg];
         if (arg.empty())
         {
             continue;
         }
         std::size_t iRepl = replacements->size();
         replacements->insert(replacements->end(), arg.begin(), arg.end());
         // The replacement token inherits padding properties from
         // macro replacement token.
         replacements->at(iRepl).setHasLeadingSpace(repl.hasLeadingSpace());
     }
 }
 }  // namespace pp

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gfx/angle/src/compiler/preprocessor/MacroExpander.cpp@97036ab72558 (annotated)

gfx/angle/src/compiler/preprocessor/MacroExpander.cpp