src/OpenGL/compiler/preprocessor/MacroExpander.cpp - SwiftShader - Git at Google

 // Copyright 2016 The SwiftShader Authors. All Rights Reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //    http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 #include "MacroExpander.h"

 #include <algorithm>
 #include <sstream>

 #include "Diagnostics.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,
                              bool parseDefined) :
 	mLexer(lexer), mMacroSet(macroSet), mDiagnostics(diagnostics), mParseDefined(parseDefined)
 {
 	mReserveToken = nullptr;
 }

 MacroExpander::~MacroExpander()
 {
 	for (size_t i = 0; i < mContextStack.size(); ++i)
 	{
 		delete mContextStack[i];
 	}

 	delete mReserveToken;
 }

 void MacroExpander::lex(Token* token)
 {
 	while (true)
 	{
 		getToken(token);

 		if (token->type != Token::IDENTIFIER)
 			break;

 		// Defined operator is parsed here since it may be generated by macro expansion.
 		// Defined operator produced by macro expansion has undefined behavior according to C++
 		// spec, which the GLSL spec references (see C++14 draft spec section 16.1.4), but this
 		// behavior is needed for passing dEQP tests, which enforce stricter compatibility between
 		// implementations.
 		if (mParseDefined && token->text == "defined")
 		{
 			bool paren = false;
 			getToken(token);
 			if (token->type == '(')
 			{
 				paren = true;
 				getToken(token);
 			}
 			if (token->type != Token::IDENTIFIER)
 			{
 				mDiagnostics->report(Diagnostics::UNEXPECTED_TOKEN, token->location,
 				                     token->text);
 				break;
 			}
 			auto iter = mMacroSet->find(token->text);
 			std::string expression = iter != mMacroSet->end() ? "1" : "0";

 			if (paren)
 			{
 				getToken(token);
 				if (token->type != ')')
 				{
 					mDiagnostics->report(Diagnostics::UNEXPECTED_TOKEN, token->location,
 					                     token->text);
 					break;
 				}
 			}

 			// We have a valid defined operator.
 			// Convert the current token into a CONST_INT token.
 			token->type = Token::CONST_INT;
 			token->text = expression;
 			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)
 	{
 		*token = *mReserveToken;
 		delete mReserveToken;
 		mReserveToken = nullptr;
 		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);
 		mReserveToken = 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 (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 (size_t i = 0; i < args->size(); ++i)
 	{
 		MacroArg& arg = args->at(i);
 		TokenLexer lexer(&arg);
 		MacroExpander expander(&lexer, mMacroSet, mDiagnostics, mParseDefined);

 		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 (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;
 		}

 		size_t iArg = std::distance(macro.parameters.begin(), iter);
 		const MacroArg& arg = args[iArg];
 		if (arg.empty())
 		{
 			continue;
 		}
 		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
	// Copyright 2016 The SwiftShader Authors. All Rights Reserved.
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	#include "MacroExpander.h"

	#include <algorithm>
	#include <sstream>

	#include "Diagnostics.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,
	bool parseDefined) :
	mLexer(lexer), mMacroSet(macroSet), mDiagnostics(diagnostics), mParseDefined(parseDefined)
	{
	mReserveToken = nullptr;
	}

	MacroExpander::~MacroExpander()
	{
	for (size_t i = 0; i < mContextStack.size(); ++i)
	{
	delete mContextStack[i];
	}

	delete mReserveToken;
	}

	void MacroExpander::lex(Token* token)
	{
	while (true)
	{
	getToken(token);

	if (token->type != Token::IDENTIFIER)
	break;

	// Defined operator is parsed here since it may be generated by macro expansion.
	// Defined operator produced by macro expansion has undefined behavior according to C++
	// spec, which the GLSL spec references (see C++14 draft spec section 16.1.4), but this
	// behavior is needed for passing dEQP tests, which enforce stricter compatibility between
	// implementations.
	if (mParseDefined && token->text == "defined")
	{
	bool paren = false;
	getToken(token);
	if (token->type == '(')
	{
	paren = true;
	getToken(token);
	}
	if (token->type != Token::IDENTIFIER)
	{
	mDiagnostics->report(Diagnostics::UNEXPECTED_TOKEN, token->location,
	token->text);
	break;
	}
	auto iter = mMacroSet->find(token->text);
	std::string expression = iter != mMacroSet->end() ? "1" : "0";

	if (paren)
	{
	getToken(token);
	if (token->type != ')')
	{
	mDiagnostics->report(Diagnostics::UNEXPECTED_TOKEN, token->location,
	token->text);
	break;
	}
	}

	// We have a valid defined operator.
	// Convert the current token into a CONST_INT token.
	token->type = Token::CONST_INT;
	token->text = expression;
	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)
	{
	token = mReserveToken;
	delete mReserveToken;
	mReserveToken = nullptr;
	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);
	mReserveToken = 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 (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 (size_t i = 0; i < args->size(); ++i)
	{
	MacroArg& arg = args->at(i);
	TokenLexer lexer(&arg);
	MacroExpander expander(&lexer, mMacroSet, mDiagnostics, mParseDefined);

	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 (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;
	}

	size_t iArg = std::distance(macro.parameters.begin(), iter);
	const MacroArg& arg = args[iArg];
	if (arg.empty())
	{
	continue;
	}
	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