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

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  • Author : Jamie Madill
    Date : 2018-11-27 11:34:27
    Hash : b980c563
    Message : Reformat all cpp and h files. This applies git cl format --full to all ANGLE sources. Bug: angleproject:2986 Change-Id: Ib504e618c1589332a37e97696cdc3515d739308f Reviewed-on: https://chromium-review.googlesource.com/c/1351367 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>

  • src/compiler/preprocessor/DirectiveParser.cpp
  • //
    // Copyright (c) 2011-2013 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 "compiler/preprocessor/DirectiveParser.h"
    
    #include <algorithm>
    #include <cstdlib>
    #include <sstream>
    
    #include "common/debug.h"
    #include "compiler/preprocessor/DiagnosticsBase.h"
    #include "compiler/preprocessor/DirectiveHandlerBase.h"
    #include "compiler/preprocessor/ExpressionParser.h"
    #include "compiler/preprocessor/MacroExpander.h"
    #include "compiler/preprocessor/Token.h"
    #include "compiler/preprocessor/Tokenizer.h"
    
    namespace angle
    {
    
    namespace
    {
    enum DirectiveType
    {
        DIRECTIVE_NONE,
        DIRECTIVE_DEFINE,
        DIRECTIVE_UNDEF,
        DIRECTIVE_IF,
        DIRECTIVE_IFDEF,
        DIRECTIVE_IFNDEF,
        DIRECTIVE_ELSE,
        DIRECTIVE_ELIF,
        DIRECTIVE_ENDIF,
        DIRECTIVE_ERROR,
        DIRECTIVE_PRAGMA,
        DIRECTIVE_EXTENSION,
        DIRECTIVE_VERSION,
        DIRECTIVE_LINE
    };
    
    DirectiveType getDirective(const pp::Token *token)
    {
        const char kDirectiveDefine[]    = "define";
        const char kDirectiveUndef[]     = "undef";
        const char kDirectiveIf[]        = "if";
        const char kDirectiveIfdef[]     = "ifdef";
        const char kDirectiveIfndef[]    = "ifndef";
        const char kDirectiveElse[]      = "else";
        const char kDirectiveElif[]      = "elif";
        const char kDirectiveEndif[]     = "endif";
        const char kDirectiveError[]     = "error";
        const char kDirectivePragma[]    = "pragma";
        const char kDirectiveExtension[] = "extension";
        const char kDirectiveVersion[]   = "version";
        const char kDirectiveLine[]      = "line";
    
        if (token->type != pp::Token::IDENTIFIER)
            return DIRECTIVE_NONE;
    
        if (token->text == kDirectiveDefine)
            return DIRECTIVE_DEFINE;
        if (token->text == kDirectiveUndef)
            return DIRECTIVE_UNDEF;
        if (token->text == kDirectiveIf)
            return DIRECTIVE_IF;
        if (token->text == kDirectiveIfdef)
            return DIRECTIVE_IFDEF;
        if (token->text == kDirectiveIfndef)
            return DIRECTIVE_IFNDEF;
        if (token->text == kDirectiveElse)
            return DIRECTIVE_ELSE;
        if (token->text == kDirectiveElif)
            return DIRECTIVE_ELIF;
        if (token->text == kDirectiveEndif)
            return DIRECTIVE_ENDIF;
        if (token->text == kDirectiveError)
            return DIRECTIVE_ERROR;
        if (token->text == kDirectivePragma)
            return DIRECTIVE_PRAGMA;
        if (token->text == kDirectiveExtension)
            return DIRECTIVE_EXTENSION;
        if (token->text == kDirectiveVersion)
            return DIRECTIVE_VERSION;
        if (token->text == kDirectiveLine)
            return DIRECTIVE_LINE;
    
        return DIRECTIVE_NONE;
    }
    
    bool isConditionalDirective(DirectiveType directive)
    {
        switch (directive)
        {
            case DIRECTIVE_IF:
            case DIRECTIVE_IFDEF:
            case DIRECTIVE_IFNDEF:
            case DIRECTIVE_ELSE:
            case DIRECTIVE_ELIF:
            case DIRECTIVE_ENDIF:
                return true;
            default:
                return false;
        }
    }
    
    // Returns true if the token represents End Of Directive.
    bool isEOD(const pp::Token *token)
    {
        return (token->type == '\n') || (token->type == pp::Token::LAST);
    }
    
    void skipUntilEOD(pp::Lexer *lexer, pp::Token *token)
    {
        while (!isEOD(token))
        {
            lexer->lex(token);
        }
    }
    
    bool isMacroNameReserved(const std::string &name)
    {
        // Names prefixed with "GL_" and the name "defined" are reserved.
        return name == "defined" || (name.substr(0, 3) == "GL_");
    }
    
    bool hasDoubleUnderscores(const std::string &name)
    {
        return (name.find("__") != std::string::npos);
    }
    
    bool isMacroPredefined(const std::string &name, const pp::MacroSet &macroSet)
    {
        pp::MacroSet::const_iterator iter = macroSet.find(name);
        return iter != macroSet.end() ? iter->second->predefined : false;
    }
    
    }  // namespace
    
    namespace pp
    {
    DirectiveParser::DirectiveParser(Tokenizer *tokenizer,
                                     MacroSet *macroSet,
                                     Diagnostics *diagnostics,
                                     DirectiveHandler *directiveHandler,
                                     const PreprocessorSettings &settings)
        : mPastFirstStatement(false),
          mSeenNonPreprocessorToken(false),
          mTokenizer(tokenizer),
          mMacroSet(macroSet),
          mDiagnostics(diagnostics),
          mDirectiveHandler(directiveHandler),
          mShaderVersion(100),
          mSettings(settings)
    {}
    
    DirectiveParser::~DirectiveParser() {}
    
    void DirectiveParser::lex(Token *token)
    {
        do
        {
            mTokenizer->lex(token);
    
            if (token->type == Token::PP_HASH)
            {
                parseDirective(token);
                mPastFirstStatement = true;
            }
            else if (!isEOD(token))
            {
                mSeenNonPreprocessorToken = true;
            }
    
            if (token->type == Token::LAST)
            {
                if (!mConditionalStack.empty())
                {
                    const ConditionalBlock &block = mConditionalStack.back();
                    mDiagnostics->report(Diagnostics::PP_CONDITIONAL_UNTERMINATED, block.location,
                                         block.type);
                }
                break;
            }
    
        } while (skipping() || (token->type == '\n'));
    
        mPastFirstStatement = true;
    }
    
    void DirectiveParser::parseDirective(Token *token)
    {
        ASSERT(token->type == Token::PP_HASH);
    
        mTokenizer->lex(token);
        if (isEOD(token))
        {
            // Empty Directive.
            return;
        }
    
        DirectiveType directive = getDirective(token);
    
        // While in an excluded conditional block/group,
        // we only parse conditional directives.
        if (skipping() && !isConditionalDirective(directive))
        {
            skipUntilEOD(mTokenizer, token);
            return;
        }
    
        switch (directive)
        {
            case DIRECTIVE_NONE:
                mDiagnostics->report(Diagnostics::PP_DIRECTIVE_INVALID_NAME, token->location,
                                     token->text);
                skipUntilEOD(mTokenizer, token);
                break;
            case DIRECTIVE_DEFINE:
                parseDefine(token);
                break;
            case DIRECTIVE_UNDEF:
                parseUndef(token);
                break;
            case DIRECTIVE_IF:
                parseIf(token);
                break;
            case DIRECTIVE_IFDEF:
                parseIfdef(token);
                break;
            case DIRECTIVE_IFNDEF:
                parseIfndef(token);
                break;
            case DIRECTIVE_ELSE:
                parseElse(token);
                break;
            case DIRECTIVE_ELIF:
                parseElif(token);
                break;
            case DIRECTIVE_ENDIF:
                parseEndif(token);
                break;
            case DIRECTIVE_ERROR:
                parseError(token);
                break;
            case DIRECTIVE_PRAGMA:
                parsePragma(token);
                break;
            case DIRECTIVE_EXTENSION:
                parseExtension(token);
                break;
            case DIRECTIVE_VERSION:
                parseVersion(token);
                break;
            case DIRECTIVE_LINE:
                parseLine(token);
                break;
            default:
                UNREACHABLE();
                break;
        }
    
        skipUntilEOD(mTokenizer, token);
        if (token->type == Token::LAST)
        {
            mDiagnostics->report(Diagnostics::PP_EOF_IN_DIRECTIVE, token->location, token->text);
        }
    }
    
    void DirectiveParser::parseDefine(Token *token)
    {
        ASSERT(getDirective(token) == DIRECTIVE_DEFINE);
    
        mTokenizer->lex(token);
        if (token->type != Token::IDENTIFIER)
        {
            mDiagnostics->report(Diagnostics::PP_UNEXPECTED_TOKEN, token->location, token->text);
            return;
        }
        if (isMacroPredefined(token->text, *mMacroSet))
        {
            mDiagnostics->report(Diagnostics::PP_MACRO_PREDEFINED_REDEFINED, token->location,
                                 token->text);
            return;
        }
        if (isMacroNameReserved(token->text))
        {
            mDiagnostics->report(Diagnostics::PP_MACRO_NAME_RESERVED, token->location, token->text);
            return;
        }
        // Using double underscores is allowed, but may result in unintended
        // behavior, so a warning is issued. At the time of writing this was
        // specified in ESSL 3.10, but the intent judging from Khronos
        // discussions and dEQP tests was that double underscores should be
        // allowed in earlier ESSL versions too.
        if (hasDoubleUnderscores(token->text))
        {
            mDiagnostics->report(Diagnostics::PP_WARNING_MACRO_NAME_RESERVED, token->location,
                                 token->text);
        }
    
        std::shared_ptr<Macro> macro = std::make_shared<Macro>();
        macro->type                  = Macro::kTypeObj;
        macro->name                  = token->text;
    
        mTokenizer->lex(token);
        if (token->type == '(' && !token->hasLeadingSpace())
        {
            // Function-like macro. Collect arguments.
            macro->type = Macro::kTypeFunc;
            do
            {
                mTokenizer->lex(token);
                if (token->type != Token::IDENTIFIER)
                    break;
    
                if (std::find(macro->parameters.begin(), macro->parameters.end(), token->text) !=
                    macro->parameters.end())
                {
                    mDiagnostics->report(Diagnostics::PP_MACRO_DUPLICATE_PARAMETER_NAMES,
                                         token->location, token->text);
                    return;
                }
    
                macro->parameters.push_back(token->text);
    
                mTokenizer->lex(token);  // Get ','.
            } while (token->type == ',');
    
            if (token->type != ')')
            {
                mDiagnostics->report(Diagnostics::PP_UNEXPECTED_TOKEN, token->location, token->text);
                return;
            }
            mTokenizer->lex(token);  // Get ')'.
        }
    
        while ((token->type != '\n') && (token->type != Token::LAST))
        {
            // Reset the token location because it is unnecessary in replacement
            // list. Resetting it also allows us to reuse Token::equals() to
            // compare macros.
            token->location = SourceLocation();
            macro->replacements.push_back(*token);
            mTokenizer->lex(token);
        }
        if (!macro->replacements.empty())
        {
            // Whitespace preceding the replacement list is not considered part of
            // the replacement list for either form of macro.
            macro->replacements.front().setHasLeadingSpace(false);
        }
    
        // Check for macro redefinition.
        MacroSet::const_iterator iter = mMacroSet->find(macro->name);
        if (iter != mMacroSet->end() && !macro->equals(*iter->second))
        {
            mDiagnostics->report(Diagnostics::PP_MACRO_REDEFINED, token->location, macro->name);
            return;
        }
        mMacroSet->insert(std::make_pair(macro->name, macro));
    }
    
    void DirectiveParser::parseUndef(Token *token)
    {
        ASSERT(getDirective(token) == DIRECTIVE_UNDEF);
    
        mTokenizer->lex(token);
        if (token->type != Token::IDENTIFIER)
        {
            mDiagnostics->report(Diagnostics::PP_UNEXPECTED_TOKEN, token->location, token->text);
            return;
        }
    
        MacroSet::iterator iter = mMacroSet->find(token->text);
        if (iter != mMacroSet->end())
        {
            if (iter->second->predefined)
            {
                mDiagnostics->report(Diagnostics::PP_MACRO_PREDEFINED_UNDEFINED, token->location,
                                     token->text);
                return;
            }
            else if (iter->second->expansionCount > 0)
            {
                mDiagnostics->report(Diagnostics::PP_MACRO_UNDEFINED_WHILE_INVOKED, token->location,
                                     token->text);
                return;
            }
            else
            {
                mMacroSet->erase(iter);
            }
        }
    
        mTokenizer->lex(token);
        if (!isEOD(token))
        {
            mDiagnostics->report(Diagnostics::PP_UNEXPECTED_TOKEN, token->location, token->text);
            skipUntilEOD(mTokenizer, token);
        }
    }
    
    void DirectiveParser::parseIf(Token *token)
    {
        ASSERT(getDirective(token) == DIRECTIVE_IF);
        parseConditionalIf(token);
    }
    
    void DirectiveParser::parseIfdef(Token *token)
    {
        ASSERT(getDirective(token) == DIRECTIVE_IFDEF);
        parseConditionalIf(token);
    }
    
    void DirectiveParser::parseIfndef(Token *token)
    {
        ASSERT(getDirective(token) == DIRECTIVE_IFNDEF);
        parseConditionalIf(token);
    }
    
    void DirectiveParser::parseElse(Token *token)
    {
        ASSERT(getDirective(token) == DIRECTIVE_ELSE);
    
        if (mConditionalStack.empty())
        {
            mDiagnostics->report(Diagnostics::PP_CONDITIONAL_ELSE_WITHOUT_IF, token->location,
                                 token->text);
            skipUntilEOD(mTokenizer, token);
            return;
        }
    
        ConditionalBlock &block = mConditionalStack.back();
        if (block.skipBlock)
        {
            // No diagnostics. Just skip the whole line.
            skipUntilEOD(mTokenizer, token);
            return;
        }
        if (block.foundElseGroup)
        {
            mDiagnostics->report(Diagnostics::PP_CONDITIONAL_ELSE_AFTER_ELSE, token->location,
                                 token->text);
            skipUntilEOD(mTokenizer, token);
            return;
        }
    
        block.foundElseGroup  = true;
        block.skipGroup       = block.foundValidGroup;
        block.foundValidGroup = true;
    
        // Check if there are extra tokens after #else.
        mTokenizer->lex(token);
        if (!isEOD(token))
        {
            mDiagnostics->report(Diagnostics::PP_CONDITIONAL_UNEXPECTED_TOKEN, token->location,
                                 token->text);
            skipUntilEOD(mTokenizer, token);
        }
    }
    
    void DirectiveParser::parseElif(Token *token)
    {
        ASSERT(getDirective(token) == DIRECTIVE_ELIF);
    
        if (mConditionalStack.empty())
        {
            mDiagnostics->report(Diagnostics::PP_CONDITIONAL_ELIF_WITHOUT_IF, token->location,
                                 token->text);
            skipUntilEOD(mTokenizer, token);
            return;
        }
    
        ConditionalBlock &block = mConditionalStack.back();
        if (block.skipBlock)
        {
            // No diagnostics. Just skip the whole line.
            skipUntilEOD(mTokenizer, token);
            return;
        }
        if (block.foundElseGroup)
        {
            mDiagnostics->report(Diagnostics::PP_CONDITIONAL_ELIF_AFTER_ELSE, token->location,
                                 token->text);
            skipUntilEOD(mTokenizer, token);
            return;
        }
        if (block.foundValidGroup)
        {
            // Do not parse the expression.
            // Also be careful not to emit a diagnostic.
            block.skipGroup = true;
            skipUntilEOD(mTokenizer, token);
            return;
        }
    
        int expression        = parseExpressionIf(token);
        block.skipGroup       = expression == 0;
        block.foundValidGroup = expression != 0;
    }
    
    void DirectiveParser::parseEndif(Token *token)
    {
        ASSERT(getDirective(token) == DIRECTIVE_ENDIF);
    
        if (mConditionalStack.empty())
        {
            mDiagnostics->report(Diagnostics::PP_CONDITIONAL_ENDIF_WITHOUT_IF, token->location,
                                 token->text);
            skipUntilEOD(mTokenizer, token);
            return;
        }
    
        mConditionalStack.pop_back();
    
        // Check if there are tokens after #endif.
        mTokenizer->lex(token);
        if (!isEOD(token))
        {
            mDiagnostics->report(Diagnostics::PP_CONDITIONAL_UNEXPECTED_TOKEN, token->location,
                                 token->text);
            skipUntilEOD(mTokenizer, token);
        }
    }
    
    void DirectiveParser::parseError(Token *token)
    {
        ASSERT(getDirective(token) == DIRECTIVE_ERROR);
    
        std::ostringstream stream;
        mTokenizer->lex(token);
        while ((token->type != '\n') && (token->type != Token::LAST))
        {
            stream << *token;
            mTokenizer->lex(token);
        }
        mDirectiveHandler->handleError(token->location, stream.str());
    }
    
    // Parses pragma of form: #pragma name[(value)].
    void DirectiveParser::parsePragma(Token *token)
    {
        ASSERT(getDirective(token) == DIRECTIVE_PRAGMA);
    
        enum State
        {
            PRAGMA_NAME,
            LEFT_PAREN,
            PRAGMA_VALUE,
            RIGHT_PAREN
        };
    
        bool valid = true;
        std::string name, value;
        int state = PRAGMA_NAME;
    
        mTokenizer->lex(token);
        bool stdgl = token->text == "STDGL";
        if (stdgl)
        {
            mTokenizer->lex(token);
        }
        while ((token->type != '\n') && (token->type != Token::LAST))
        {
            switch (state++)
            {
                case PRAGMA_NAME:
                    name  = token->text;
                    valid = valid && (token->type == Token::IDENTIFIER);
                    break;
                case LEFT_PAREN:
                    valid = valid && (token->type == '(');
                    break;
                case PRAGMA_VALUE:
                    value = token->text;
                    valid = valid && (token->type == Token::IDENTIFIER);
                    break;
                case RIGHT_PAREN:
                    valid = valid && (token->type == ')');
                    break;
                default:
                    valid = false;
                    break;
            }
            mTokenizer->lex(token);
        }
    
        valid = valid && ((state == PRAGMA_NAME) ||     // Empty pragma.
                          (state == LEFT_PAREN) ||      // Without value.
                          (state == RIGHT_PAREN + 1));  // With value.
        if (!valid)
        {
            mDiagnostics->report(Diagnostics::PP_UNRECOGNIZED_PRAGMA, token->location, name);
        }
        else if (state > PRAGMA_NAME)  // Do not notify for empty pragma.
        {
            mDirectiveHandler->handlePragma(token->location, name, value, stdgl);
        }
    }
    
    void DirectiveParser::parseExtension(Token *token)
    {
        ASSERT(getDirective(token) == DIRECTIVE_EXTENSION);
    
        enum State
        {
            EXT_NAME,
            COLON,
            EXT_BEHAVIOR
        };
    
        bool valid = true;
        std::string name, behavior;
        int state = EXT_NAME;
    
        mTokenizer->lex(token);
        while ((token->type != '\n') && (token->type != Token::LAST))
        {
            switch (state++)
            {
                case EXT_NAME:
                    if (valid && (token->type != Token::IDENTIFIER))
                    {
                        mDiagnostics->report(Diagnostics::PP_INVALID_EXTENSION_NAME, token->location,
                                             token->text);
                        valid = false;
                    }
                    if (valid)
                        name = token->text;
                    break;
                case COLON:
                    if (valid && (token->type != ':'))
                    {
                        mDiagnostics->report(Diagnostics::PP_UNEXPECTED_TOKEN, token->location,
                                             token->text);
                        valid = false;
                    }
                    break;
                case EXT_BEHAVIOR:
                    if (valid && (token->type != Token::IDENTIFIER))
                    {
                        mDiagnostics->report(Diagnostics::PP_INVALID_EXTENSION_BEHAVIOR,
                                             token->location, token->text);
                        valid = false;
                    }
                    if (valid)
                        behavior = token->text;
                    break;
                default:
                    if (valid)
                    {
                        mDiagnostics->report(Diagnostics::PP_UNEXPECTED_TOKEN, token->location,
                                             token->text);
                        valid = false;
                    }
                    break;
            }
            mTokenizer->lex(token);
        }
        if (valid && (state != EXT_BEHAVIOR + 1))
        {
            mDiagnostics->report(Diagnostics::PP_INVALID_EXTENSION_DIRECTIVE, token->location,
                                 token->text);
            valid = false;
        }
        if (valid && mSeenNonPreprocessorToken)
        {
            if (mShaderVersion >= 300)
            {
                mDiagnostics->report(Diagnostics::PP_NON_PP_TOKEN_BEFORE_EXTENSION_ESSL3,
                                     token->location, token->text);
                valid = false;
            }
            else
            {
                mDiagnostics->report(Diagnostics::PP_NON_PP_TOKEN_BEFORE_EXTENSION_ESSL1,
                                     token->location, token->text);
            }
        }
        if (valid)
            mDirectiveHandler->handleExtension(token->location, name, behavior);
    }
    
    void DirectiveParser::parseVersion(Token *token)
    {
        ASSERT(getDirective(token) == DIRECTIVE_VERSION);
    
        if (mPastFirstStatement)
        {
            mDiagnostics->report(Diagnostics::PP_VERSION_NOT_FIRST_STATEMENT, token->location,
                                 token->text);
            skipUntilEOD(mTokenizer, token);
            return;
        }
    
        enum State
        {
            VERSION_NUMBER,
            VERSION_PROFILE,
            VERSION_ENDLINE
        };
    
        bool valid  = true;
        int version = 0;
        int state   = VERSION_NUMBER;
    
        mTokenizer->lex(token);
        while (valid && (token->type != '\n') && (token->type != Token::LAST))
        {
            switch (state)
            {
                case VERSION_NUMBER:
                    if (token->type != Token::CONST_INT)
                    {
                        mDiagnostics->report(Diagnostics::PP_INVALID_VERSION_NUMBER, token->location,
                                             token->text);
                        valid = false;
                    }
                    if (valid && !token->iValue(&version))
                    {
                        mDiagnostics->report(Diagnostics::PP_INTEGER_OVERFLOW, token->location,
                                             token->text);
                        valid = false;
                    }
                    if (valid)
                    {
                        state = (version < 300) ? VERSION_ENDLINE : VERSION_PROFILE;
                    }
                    break;
                case VERSION_PROFILE:
                    if (token->type != Token::IDENTIFIER || token->text != "es")
                    {
                        mDiagnostics->report(Diagnostics::PP_INVALID_VERSION_DIRECTIVE, token->location,
                                             token->text);
                        valid = false;
                    }
                    state = VERSION_ENDLINE;
                    break;
                default:
                    mDiagnostics->report(Diagnostics::PP_UNEXPECTED_TOKEN, token->location,
                                         token->text);
                    valid = false;
                    break;
            }
    
            mTokenizer->lex(token);
        }
    
        if (valid && (state != VERSION_ENDLINE))
        {
            mDiagnostics->report(Diagnostics::PP_INVALID_VERSION_DIRECTIVE, token->location,
                                 token->text);
            valid = false;
        }
    
        if (valid && version >= 300 && token->location.line > 1)
        {
            mDiagnostics->report(Diagnostics::PP_VERSION_NOT_FIRST_LINE_ESSL3, token->location,
                                 token->text);
            valid = false;
        }
    
        if (valid)
        {
            mDirectiveHandler->handleVersion(token->location, version);
            mShaderVersion = version;
            PredefineMacro(mMacroSet, "__VERSION__", version);
        }
    }
    
    void DirectiveParser::parseLine(Token *token)
    {
        ASSERT(getDirective(token) == DIRECTIVE_LINE);
    
        bool valid            = true;
        bool parsedFileNumber = false;
        int line = 0, file = 0;
    
        MacroExpander macroExpander(mTokenizer, mMacroSet, mDiagnostics, mSettings, false);
    
        // Lex the first token after "#line" so we can check it for EOD.
        macroExpander.lex(token);
    
        if (isEOD(token))
        {
            mDiagnostics->report(Diagnostics::PP_INVALID_LINE_DIRECTIVE, token->location, token->text);
            valid = false;
        }
        else
        {
            ExpressionParser expressionParser(&macroExpander, mDiagnostics);
            ExpressionParser::ErrorSettings errorSettings;
    
            // See GLES3 section 12.42
            errorSettings.integerLiteralsMustFit32BitSignedRange = true;
    
            errorSettings.unexpectedIdentifier = Diagnostics::PP_INVALID_LINE_NUMBER;
            // The first token was lexed earlier to check if it was EOD. Include
            // the token in parsing for a second time by setting the
            // parsePresetToken flag to true.
            expressionParser.parse(token, &line, true, errorSettings, &valid);
            if (!isEOD(token) && valid)
            {
                errorSettings.unexpectedIdentifier = Diagnostics::PP_INVALID_FILE_NUMBER;
                // After parsing the line expression expressionParser has also
                // advanced to the first token of the file expression - this is the
                // token that makes the parser reduce the "input" rule for the line
                // expression and stop. So we're using parsePresetToken = true here
                // as well.
                expressionParser.parse(token, &file, true, errorSettings, &valid);
                parsedFileNumber = true;
            }
            if (!isEOD(token))
            {
                if (valid)
                {
                    mDiagnostics->report(Diagnostics::PP_UNEXPECTED_TOKEN, token->location,
                                         token->text);
                    valid = false;
                }
                skipUntilEOD(mTokenizer, token);
            }
        }
    
        if (valid)
        {
            mTokenizer->setLineNumber(line);
            if (parsedFileNumber)
                mTokenizer->setFileNumber(file);
        }
    }
    
    bool DirectiveParser::skipping() const
    {
        if (mConditionalStack.empty())
            return false;
    
        const ConditionalBlock &block = mConditionalStack.back();
        return block.skipBlock || block.skipGroup;
    }
    
    void DirectiveParser::parseConditionalIf(Token *token)
    {
        ConditionalBlock block;
        block.type     = token->text;
        block.location = token->location;
    
        if (skipping())
        {
            // This conditional block is inside another conditional group
            // which is skipped. As a consequence this whole block is skipped.
            // Be careful not to parse the conditional expression that might
            // emit a diagnostic.
            skipUntilEOD(mTokenizer, token);
            block.skipBlock = true;
        }
        else
        {
            DirectiveType directive = getDirective(token);
    
            int expression = 0;
            switch (directive)
            {
                case DIRECTIVE_IF:
                    expression = parseExpressionIf(token);
                    break;
                case DIRECTIVE_IFDEF:
                    expression = parseExpressionIfdef(token);
                    break;
                case DIRECTIVE_IFNDEF:
                    expression = parseExpressionIfdef(token) == 0 ? 1 : 0;
                    break;
                default:
                    UNREACHABLE();
                    break;
            }
            block.skipGroup       = expression == 0;
            block.foundValidGroup = expression != 0;
        }
        mConditionalStack.push_back(block);
    }
    
    int DirectiveParser::parseExpressionIf(Token *token)
    {
        ASSERT((getDirective(token) == DIRECTIVE_IF) || (getDirective(token) == DIRECTIVE_ELIF));
    
        MacroExpander macroExpander(mTokenizer, mMacroSet, mDiagnostics, mSettings, true);
        ExpressionParser expressionParser(&macroExpander, mDiagnostics);
    
        int expression = 0;
        ExpressionParser::ErrorSettings errorSettings;
        errorSettings.integerLiteralsMustFit32BitSignedRange = false;
        errorSettings.unexpectedIdentifier = Diagnostics::PP_CONDITIONAL_UNEXPECTED_TOKEN;
    
        bool valid = true;
        expressionParser.parse(token, &expression, false, errorSettings, &valid);
    
        // Check if there are tokens after #if expression.
        if (!isEOD(token))
        {
            mDiagnostics->report(Diagnostics::PP_CONDITIONAL_UNEXPECTED_TOKEN, token->location,
                                 token->text);
            skipUntilEOD(mTokenizer, token);
        }
    
        return expression;
    }
    
    int DirectiveParser::parseExpressionIfdef(Token *token)
    {
        ASSERT((getDirective(token) == DIRECTIVE_IFDEF) || (getDirective(token) == DIRECTIVE_IFNDEF));
    
        mTokenizer->lex(token);
        if (token->type != Token::IDENTIFIER)
        {
            mDiagnostics->report(Diagnostics::PP_UNEXPECTED_TOKEN, token->location, token->text);
            skipUntilEOD(mTokenizer, token);
            return 0;
        }
    
        MacroSet::const_iterator iter = mMacroSet->find(token->text);
        int expression                = iter != mMacroSet->end() ? 1 : 0;
    
        // Check if there are tokens after #ifdef expression.
        mTokenizer->lex(token);
        if (!isEOD(token))
        {
            mDiagnostics->report(Diagnostics::PP_CONDITIONAL_UNEXPECTED_TOKEN, token->location,
                                 token->text);
            skipUntilEOD(mTokenizer, token);
        }
        return expression;
    }
    
    }  // namespace pp
    
    }  // namespace angle