MacroExpander.cpp

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Author : Olli Etuaho
Date : 2016-03-04 15:06:51
Hash : 1b2f1629
Message : Forbid defined operator generated by macro expansion After lengthy debate, the GLES working group recommended that this should be an error in WebGL, though old specs were not updated. Make ANGLE follow the WebGL spec and generate an error in this case. This is a partial revert of the patch which added support for defined operator generated by macro expansion. The preprocessor unit tests added by the reverted commit are kept, but their expectations are changed. This breaks some dEQP tests that are not in line with the WebGL spec. BUG=angleproject:1335 TEST=angle_unittests, WebGL conformance tests Change-Id: I7d8a1d42c61367197f2aed4ca4de9297cc48acfc Reviewed-on: https://chromium-review.googlesource.com/352471 Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
src/compiler/preprocessor/MacroExpander.cpp
//
// 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();
    }

    void lex(Token *token) override
    {
        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();

    // In the case of an object-like macro, the replacement list gets its location
    // from the identifier, but in the case of a function-like macro, the replacement
    // list gets its location from the closing parenthesis of the macro invocation.
    // This is tested by dEQP-GLES3.functional.shaders.preprocessor.predefined_macros.*
    SourceLocation replacementLocation = identifier.location;
    if (macro.type == Macro::kTypeObj)
    {
        replacements->assign(macro.replacements.begin(),
                             macro.replacements.end());

        if (macro.predefined)
        {
            const char kLine[] = "__LINE__";
            const char 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, &replacementLocation))
            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 = replacementLocation;
    }
    return true;
}

bool MacroExpander::collectMacroArgs(const Macro &macro,
                                     const Token &identifier,
                                     std::vector<MacroArg> *args,
                                     SourceLocation *closingParenthesisLocation)
{
    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::PP_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;
            *closingParenthesisLocation = token.location;
            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::PP_MACRO_TOO_FEW_ARGS :
            Diagnostics::PP_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
kc3-lang/angle/src/compiler/preprocessor/MacroExpander.cpp

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kc3-lang/angle /src/compiler/preprocessor/MacroExpander.cpp
