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Parser.cpp
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Parser.cpp
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/*
* Copyright (C) 2022-2023 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "Parser.h"
#include "AST.h"
#include "Lexer.h"
#include "ParserPrivate.h"
#include "WGSLShaderModule.h"
#include <wtf/text/StringBuilder.h>
namespace WGSL {
#define START_PARSE() \
auto _startOfElementPosition = m_lexer.currentPosition();
#define CURRENT_SOURCE_SPAN() \
SourceSpan(_startOfElementPosition, m_lexer.currentPosition())
#define MAKE_NODE_UNIQUE_REF(type, ...) \
makeUniqueRef<AST::type>(CURRENT_SOURCE_SPAN() __VA_OPT__(,) __VA_ARGS__) /* NOLINT */
#define RETURN_NODE(type, ...) \
do { \
AST::type astNodeResult(CURRENT_SOURCE_SPAN(), __VA_ARGS__); \
return { WTFMove(astNodeResult) }; \
} while (false)
// Passing 0 arguments beyond the type to RETURN_NODE is invalid because of a stupid limitation of the C preprocessor
#define RETURN_NODE_NO_ARGS(type) \
do { \
AST::type astNodeResult(CURRENT_SOURCE_SPAN()); \
return { WTFMove(astNodeResult) }; \
} while (false)
#define RETURN_NODE_REF(type, ...) \
return { adoptRef(*new AST::type(CURRENT_SOURCE_SPAN(), __VA_ARGS__)) };
#define RETURN_NODE_UNIQUE_REF(type, ...) \
return { MAKE_NODE_UNIQUE_REF(type, __VA_ARGS__) };
// Passing 0 arguments beyond the type to RETURN_NODE_UNIQUE_REF is invalid because of a stupid limitation of the C preprocessor
#define RETURN_NODE_UNIQUE_REF_NO_ARGS(type) \
return { makeUniqueRef<AST::type>(CURRENT_SOURCE_SPAN()) };
#define FAIL(string) \
return makeUnexpected(Error(string, CURRENT_SOURCE_SPAN()));
// Warning: cannot use the do..while trick because it defines a new identifier named `name`.
// So do not use after an if/for/while without braces.
#define PARSE(name, element, ...) \
auto name##Expected = parse##element(__VA_ARGS__); \
if (!name##Expected) \
return makeUnexpected(name##Expected.error()); \
auto& name = *name##Expected;
#define PARSE_MOVE(name, element, ...) \
auto name##Expected = parse##element(__VA_ARGS__); \
if (!name##Expected) \
return makeUnexpected(name##Expected.error()); \
name = WTFMove(*name##Expected);
// Warning: cannot use the do..while trick because it defines a new identifier named `name`.
// So do not use after an if/for/while without braces.
#define CONSUME_TYPE_NAMED(name, type) \
auto name##Expected = consumeType(TokenType::type); \
if (!name##Expected) { \
StringBuilder builder; \
builder.append("Expected a "); \
builder.append(toString(TokenType::type)); \
builder.append(", but got a "); \
builder.append(toString(name##Expected.error())); \
FAIL(builder.toString()); \
} \
auto& name = *name##Expected;
#define CONSUME_TYPE(type) \
do { \
auto expectedToken = consumeType(TokenType::type); \
if (!expectedToken) { \
StringBuilder builder; \
builder.append("Expected a "); \
builder.append(toString(TokenType::type)); \
builder.append(", but got a "); \
builder.append(toString(expectedToken.error())); \
FAIL(builder.toString()); \
} \
} while (false)
static bool canContinueMultiplicativeExpression(const Token& token)
{
switch (token.m_type) {
case TokenType::Modulo:
case TokenType::Slash:
case TokenType::Star:
return true;
default:
return false;
}
}
static bool canContinueAdditiveExpression(const Token& token)
{
switch (token.m_type) {
case TokenType::Minus:
case TokenType::Plus:
return true;
default:
return canContinueMultiplicativeExpression(token);
}
}
template<typename Lexer>
std::optional<Error> parse(ShaderModule& shaderModule)
{
Lexer lexer(shaderModule.source());
Parser parser(shaderModule, lexer);
auto result = parser.parseShader();
if (!result.has_value())
return result.error();
return std::nullopt;
}
std::optional<Error> parse(ShaderModule& shaderModule)
{
if (shaderModule.source().is8Bit())
return parse<Lexer<LChar>>(shaderModule);
return parse<Lexer<UChar>>(shaderModule);
}
template<typename Lexer>
Expected<AST::Expression::Ref, Error> parseExpression(const String& source)
{
ShaderModule shaderModule(source);
Lexer lexer(shaderModule.source());
Parser parser(shaderModule, lexer);
return parser.parseExpression();
}
Expected<AST::Expression::Ref, Error> parseExpression(const String& source)
{
if (source.is8Bit())
return parseExpression<Lexer<LChar>>(source);
return parseExpression<Lexer<UChar>>(source);
}
template<typename Lexer>
Expected<Token, TokenType> Parser<Lexer>::consumeType(TokenType type)
{
if (current().m_type == type) {
Expected<Token, TokenType> result = { m_current };
m_current = m_lexer.lex();
return result;
}
return makeUnexpected(current().m_type);
}
template<typename Lexer>
void Parser<Lexer>::consume()
{
m_current = m_lexer.lex();
}
template<typename Lexer>
Expected<void, Error> Parser<Lexer>::parseShader()
{
// FIXME: parse directives here.
while (!m_lexer.isAtEndOfFile()) {
auto globalExpected = parseGlobalDecl();
if (!globalExpected)
return makeUnexpected(globalExpected.error());
}
return { };
}
template<typename Lexer>
Expected<AST::Identifier, Error> Parser<Lexer>::parseIdentifier()
{
START_PARSE();
CONSUME_TYPE_NAMED(name, Identifier);
return AST::Identifier::makeWithSpan(CURRENT_SOURCE_SPAN(), WTFMove(name.m_ident));
}
template<typename Lexer>
Expected<void, Error> Parser<Lexer>::parseGlobalDecl()
{
START_PARSE();
while (current().m_type == TokenType::Semicolon)
consume();
PARSE(attributes, Attributes);
switch (current().m_type) {
case TokenType::KeywordStruct: {
PARSE(structure, Structure, WTFMove(attributes));
m_shaderModule.structures().append(WTFMove(structure));
return { };
}
case TokenType::KeywordVar: {
PARSE(variable, VariableWithAttributes, WTFMove(attributes));
CONSUME_TYPE(Semicolon);
m_shaderModule.variables().append(WTFMove(variable));
return { };
}
case TokenType::KeywordFn: {
PARSE(fn, Function, WTFMove(attributes));
m_shaderModule.functions().append(makeUniqueRef<AST::Function>(WTFMove(fn)));
return { };
}
default:
FAIL("Trying to parse a GlobalDecl, expected 'var', 'fn', or 'struct'."_s);
}
}
template<typename Lexer>
Expected<AST::Attribute::List, Error> Parser<Lexer>::parseAttributes()
{
AST::Attribute::List attributes;
while (current().m_type == TokenType::Attribute) {
PARSE(firstAttribute, Attribute);
attributes.append(WTFMove(firstAttribute));
}
return { WTFMove(attributes) };
}
template<typename Lexer>
Expected<Ref<AST::Attribute>, Error> Parser<Lexer>::parseAttribute()
{
START_PARSE();
CONSUME_TYPE(Attribute);
CONSUME_TYPE_NAMED(ident, Identifier);
if (ident.m_ident == "group"_s) {
CONSUME_TYPE(ParenLeft);
// FIXME: should more kinds of literals be accepted here?
CONSUME_TYPE_NAMED(id, IntegerLiteral);
CONSUME_TYPE(ParenRight);
RETURN_NODE_REF(GroupAttribute, id.m_literalValue);
}
if (ident.m_ident == "binding"_s) {
CONSUME_TYPE(ParenLeft);
// FIXME: should more kinds of literals be accepted here?
CONSUME_TYPE_NAMED(id, IntegerLiteral);
CONSUME_TYPE(ParenRight);
RETURN_NODE_REF(BindingAttribute, id.m_literalValue);
}
if (ident.m_ident == "location"_s) {
CONSUME_TYPE(ParenLeft);
// FIXME: should more kinds of literals be accepted here?
CONSUME_TYPE_NAMED(id, IntegerLiteral);
CONSUME_TYPE(ParenRight);
RETURN_NODE_REF(LocationAttribute, id.m_literalValue);
}
if (ident.m_ident == "builtin"_s) {
CONSUME_TYPE(ParenLeft);
PARSE(name, Identifier);
CONSUME_TYPE(ParenRight);
RETURN_NODE_REF(BuiltinAttribute, WTFMove(name));
}
if (ident.m_ident == "workgroup_size"_s) {
CONSUME_TYPE(ParenLeft);
// FIXME: should more kinds of literals be accepted here?
CONSUME_TYPE_NAMED(id, IntegerLiteralUnsigned);
CONSUME_TYPE(ParenRight);
RETURN_NODE_REF(WorkgroupSizeAttribute, id.m_literalValue);
}
// https://gpuweb.github.io/gpuweb/wgsl/#pipeline-stage-attributes
if (ident.m_ident == "vertex"_s)
RETURN_NODE_REF(StageAttribute, AST::StageAttribute::Stage::Vertex);
if (ident.m_ident == "compute"_s)
RETURN_NODE_REF(StageAttribute, AST::StageAttribute::Stage::Compute);
if (ident.m_ident == "fragment"_s)
RETURN_NODE_REF(StageAttribute, AST::StageAttribute::Stage::Fragment);
FAIL("Unknown attribute. Supported attributes are 'group', 'binding', 'location', 'builtin', 'vertex', 'compute', 'fragment'."_s);
}
template<typename Lexer>
Expected<AST::Structure::Ref, Error> Parser<Lexer>::parseStructure(AST::Attribute::List&& attributes)
{
START_PARSE();
CONSUME_TYPE(KeywordStruct);
PARSE(name, Identifier);
CONSUME_TYPE(BraceLeft);
AST::StructureMember::List members;
while (current().m_type != TokenType::BraceRight) {
PARSE(member, StructureMember);
members.append(makeUniqueRef<AST::StructureMember>(WTFMove(member)));
if (current().m_type == TokenType::Comma)
consume();
else
break;
}
CONSUME_TYPE(BraceRight);
RETURN_NODE_UNIQUE_REF(Structure, WTFMove(name), WTFMove(members), WTFMove(attributes), AST::StructureRole::UserDefined);
}
template<typename Lexer>
Expected<AST::StructureMember, Error> Parser<Lexer>::parseStructureMember()
{
START_PARSE();
PARSE(attributes, Attributes);
PARSE(name, Identifier);
CONSUME_TYPE(Colon);
PARSE(type, TypeName);
RETURN_NODE(StructureMember, WTFMove(name), WTFMove(type), WTFMove(attributes));
}
template<typename Lexer>
Expected<AST::TypeName::Ref, Error> Parser<Lexer>::parseTypeName()
{
START_PARSE();
if (current().m_type == TokenType::KeywordArray)
return parseArrayType();
if (current().m_type == TokenType::KeywordI32) {
consume();
RETURN_NODE_REF(NamedTypeName, AST::Identifier::makeWithSpan(CURRENT_SOURCE_SPAN(), StringView { "i32"_s }));
}
if (current().m_type == TokenType::KeywordF32) {
consume();
RETURN_NODE_REF(NamedTypeName, AST::Identifier::makeWithSpan(CURRENT_SOURCE_SPAN(), StringView { "f32"_s }));
}
if (current().m_type == TokenType::KeywordU32) {
consume();
RETURN_NODE_REF(NamedTypeName, AST::Identifier::makeWithSpan(CURRENT_SOURCE_SPAN(), StringView { "u32"_s }));
}
if (current().m_type == TokenType::KeywordBool) {
consume();
RETURN_NODE_REF(NamedTypeName, AST::Identifier::makeWithSpan(CURRENT_SOURCE_SPAN(), StringView { "bool"_s }));
}
if (current().m_type == TokenType::Identifier) {
PARSE(name, Identifier);
return parseTypeNameAfterIdentifier(WTFMove(name), _startOfElementPosition);
}
FAIL("Tried parsing a type and it did not start with an identifier"_s);
}
template<typename Lexer>
Expected<AST::TypeName::Ref, Error> Parser<Lexer>::parseTypeNameAfterIdentifier(AST::Identifier&& name, SourcePosition _startOfElementPosition)
{
if (auto kind = AST::ParameterizedTypeName::stringViewToKind(name.id())) {
CONSUME_TYPE(Lt);
PARSE(elementType, TypeName);
CONSUME_TYPE(Gt);
RETURN_NODE_REF(ParameterizedTypeName, *kind, WTFMove(elementType));
}
RETURN_NODE_REF(NamedTypeName, WTFMove(name));
}
template<typename Lexer>
Expected<AST::TypeName::Ref, Error> Parser<Lexer>::parseArrayType()
{
START_PARSE();
CONSUME_TYPE(KeywordArray);
AST::TypeName::Ptr maybeElementType;
AST::Expression::Ptr maybeElementCount;
if (current().m_type == TokenType::Lt) {
// We differ from the WGSL grammar here by allowing the type to be optional,
// which allows us to use `parseArrayType` in `parseCallExpression`.
consume();
PARSE(elementType, TypeName);
maybeElementType = WTFMove(elementType);
if (current().m_type == TokenType::Comma) {
consume();
// FIXME: According to https://www.w3.org/TR/WGSL/#syntax-element_count_expression
// this should be: AdditiveExpression | BitwiseExpression.
//
// The WGSL grammar doesn't specify expression operator precedence so
// until then just parse AdditiveExpression.
PARSE(elementCountLHS, UnaryExpression);
PARSE(elementCount, AdditiveExpressionPostUnary, WTFMove(elementCountLHS));
maybeElementCount = elementCount.moveToUniquePtr();
}
CONSUME_TYPE(Gt);
}
RETURN_NODE_REF(ArrayTypeName, WTFMove(maybeElementType), WTFMove(maybeElementCount));
}
template<typename Lexer>
Expected<AST::Variable::Ref, Error> Parser<Lexer>::parseVariable()
{
return parseVariableWithAttributes(AST::Attribute::List { });
}
template<typename Lexer>
Expected<AST::Variable::Ref, Error> Parser<Lexer>::parseVariableWithAttributes(AST::Attribute::List&& attributes)
{
START_PARSE();
CONSUME_TYPE(KeywordVar);
std::unique_ptr<AST::VariableQualifier> maybeQualifier = nullptr;
if (current().m_type == TokenType::Lt) {
PARSE(variableQualifier, VariableQualifier);
maybeQualifier = WTF::makeUnique<AST::VariableQualifier>(WTFMove(variableQualifier));
}
PARSE(name, Identifier);
AST::TypeName::Ptr maybeType = nullptr;
if (current().m_type == TokenType::Colon) {
consume();
PARSE(TypeName, TypeName);
maybeType = WTFMove(TypeName);
}
std::unique_ptr<AST::Expression> maybeInitializer = nullptr;
if (current().m_type == TokenType::Equal) {
consume();
PARSE(initializerExpr, Expression);
maybeInitializer = initializerExpr.moveToUniquePtr();
}
RETURN_NODE_UNIQUE_REF(Variable, WTFMove(name), WTFMove(maybeQualifier), WTFMove(maybeType), WTFMove(maybeInitializer), WTFMove(attributes));
}
template<typename Lexer>
Expected<AST::VariableQualifier, Error> Parser<Lexer>::parseVariableQualifier()
{
START_PARSE();
CONSUME_TYPE(Lt);
PARSE(storageClass, StorageClass);
// FIXME: verify that Read is the correct default in all cases.
AST::AccessMode accessMode = AST::AccessMode::Read;
if (current().m_type == TokenType::Comma) {
consume();
PARSE(actualAccessMode, AccessMode);
accessMode = actualAccessMode;
}
CONSUME_TYPE(Gt);
RETURN_NODE(VariableQualifier, storageClass, accessMode);
}
template<typename Lexer>
Expected<AST::StorageClass, Error> Parser<Lexer>::parseStorageClass()
{
START_PARSE();
if (current().m_type == TokenType::KeywordFunction) {
consume();
return { AST::StorageClass::Function };
}
if (current().m_type == TokenType::KeywordPrivate) {
consume();
return { AST::StorageClass::Private };
}
if (current().m_type == TokenType::KeywordWorkgroup) {
consume();
return { AST::StorageClass::Workgroup };
}
if (current().m_type == TokenType::KeywordUniform) {
consume();
return { AST::StorageClass::Uniform };
}
if (current().m_type == TokenType::KeywordStorage) {
consume();
return { AST::StorageClass::Storage };
}
FAIL("Expected one of 'function'/'private'/'storage'/'uniform'/'workgroup'"_s);
}
template<typename Lexer>
Expected<AST::AccessMode, Error> Parser<Lexer>::parseAccessMode()
{
START_PARSE();
if (current().m_type == TokenType::KeywordRead) {
consume();
return { AST::AccessMode::Read };
}
if (current().m_type == TokenType::KeywordWrite) {
consume();
return { AST::AccessMode::Write };
}
if (current().m_type == TokenType::KeywordReadWrite) {
consume();
return { AST::AccessMode::ReadWrite };
}
FAIL("Expected one of 'read'/'write'/'read_write'"_s);
}
template<typename Lexer>
Expected<AST::Function, Error> Parser<Lexer>::parseFunction(AST::Attribute::List&& attributes)
{
START_PARSE();
CONSUME_TYPE(KeywordFn);
PARSE(name, Identifier);
CONSUME_TYPE(ParenLeft);
AST::ParameterValue::List parameters;
while (current().m_type != TokenType::ParenRight) {
PARSE(parameter, ParameterValue);
parameters.append(makeUniqueRef<AST::ParameterValue>(WTFMove(parameter)));
if (current().m_type == TokenType::Comma)
consume();
else
break;
}
CONSUME_TYPE(ParenRight);
AST::Attribute::List returnAttributes;
AST::TypeName::Ptr maybeReturnType = nullptr;
if (current().m_type == TokenType::Arrow) {
consume();
PARSE(parsedReturnAttributes, Attributes);
returnAttributes = WTFMove(parsedReturnAttributes);
PARSE(type, TypeName);
maybeReturnType = WTFMove(type);
}
PARSE(body, CompoundStatement);
RETURN_NODE(Function, WTFMove(name), WTFMove(parameters), WTFMove(maybeReturnType), WTFMove(body), WTFMove(attributes), WTFMove(returnAttributes));
}
template<typename Lexer>
Expected<AST::ParameterValue, Error> Parser<Lexer>::parseParameterValue()
{
START_PARSE();
PARSE(attributes, Attributes);
PARSE(name, Identifier)
CONSUME_TYPE(Colon);
PARSE(type, TypeName);
RETURN_NODE(ParameterValue, WTFMove(name), WTFMove(type), WTFMove(attributes), AST::ParameterRole::UserDefined);
}
template<typename Lexer>
Expected<UniqueRef<AST::Statement>, Error> Parser<Lexer>::parseStatement()
{
START_PARSE();
while (current().m_type == TokenType::Semicolon)
consume();
switch (current().m_type) {
case TokenType::BraceLeft: {
PARSE(compoundStmt, CompoundStatement);
return { makeUniqueRef<AST::CompoundStatement>(WTFMove(compoundStmt)) };
}
case TokenType::KeywordReturn: {
PARSE(returnStmt, ReturnStatement);
CONSUME_TYPE(Semicolon);
return { makeUniqueRef<AST::ReturnStatement>(WTFMove(returnStmt)) };
}
case TokenType::KeywordVar: {
PARSE(variable, Variable);
CONSUME_TYPE(Semicolon);
return { makeUniqueRef<AST::VariableStatement>(CURRENT_SOURCE_SPAN(), WTFMove(variable)) };
}
case TokenType::Identifier: {
// FIXME: there will be other cases here eventually for function calls
PARSE(lhs, LHSExpression);
CONSUME_TYPE(Equal);
PARSE(rhs, Expression);
CONSUME_TYPE(Semicolon);
RETURN_NODE_UNIQUE_REF(AssignmentStatement, WTFMove(lhs), WTFMove(rhs));
}
default:
FAIL("Not a valid statement"_s);
}
}
template<typename Lexer>
Expected<AST::CompoundStatement, Error> Parser<Lexer>::parseCompoundStatement()
{
START_PARSE();
CONSUME_TYPE(BraceLeft);
AST::Statement::List statements;
while (current().m_type != TokenType::BraceRight) {
PARSE(stmt, Statement);
statements.append(WTFMove(stmt));
}
CONSUME_TYPE(BraceRight);
RETURN_NODE(CompoundStatement, WTFMove(statements));
}
template<typename Lexer>
Expected<AST::ReturnStatement, Error> Parser<Lexer>::parseReturnStatement()
{
START_PARSE();
CONSUME_TYPE(KeywordReturn);
if (current().m_type == TokenType::Semicolon) {
RETURN_NODE(ReturnStatement, { });
}
PARSE(expr, Expression);
RETURN_NODE(ReturnStatement, expr.moveToUniquePtr());
}
template<typename Lexer>
Expected<UniqueRef<AST::Expression>, Error> Parser<Lexer>::parseRelationalExpressionPostUnary(AST::Expression::Ref&& lhs)
{
// FIXME: fill in
return parseShiftExpressionPostUnary(WTFMove(lhs));
}
template<typename Lexer>
Expected<UniqueRef<AST::Expression>, Error> Parser<Lexer>::parseShiftExpressionPostUnary(AST::Expression::Ref&& lhs)
{
if (canContinueAdditiveExpression(current()))
return parseAdditiveExpressionPostUnary(WTFMove(lhs));
START_PARSE();
switch (current().m_type) {
case TokenType::GtGt: {
consume();
PARSE(rhs, UnaryExpression);
RETURN_NODE_UNIQUE_REF(BinaryExpression, WTFMove(lhs), WTFMove(rhs), AST::BinaryOperation::RightShift);
}
case TokenType::LtLt: {
consume();
PARSE(rhs, UnaryExpression);
RETURN_NODE_UNIQUE_REF(BinaryExpression, WTFMove(lhs), WTFMove(rhs), AST::BinaryOperation::LeftShift);
}
default:
return WTFMove(lhs);
}
}
template<typename Lexer>
Expected<UniqueRef<AST::Expression>, Error> Parser<Lexer>::parseAdditiveExpressionPostUnary(AST::Expression::Ref&& lhs)
{
START_PARSE();
PARSE_MOVE(lhs, MultiplicativeExpressionPostUnary, WTFMove(lhs));
while (canContinueAdditiveExpression(current())) {
auto op = AST::BinaryOperation::Add;
switch (current().m_type) {
case TokenType::Minus:
op = AST::BinaryOperation::Subtract;
break;
case TokenType::Plus:
op = AST::BinaryOperation::Add;
break;
default:
// parseMultiplicativeExpression handles multiplicative operators so
// token should be PLUS or MINUS.
RELEASE_ASSERT_NOT_REACHED_WITH_MESSAGE("Expected + or -");
}
consume();
PARSE(unary, UnaryExpression);
PARSE(rhs, MultiplicativeExpressionPostUnary, WTFMove(unary));
lhs = MAKE_NODE_UNIQUE_REF(BinaryExpression, WTFMove(lhs), WTFMove(rhs), op);
}
return WTFMove(lhs);
}
template<typename Lexer>
Expected<UniqueRef<AST::Expression>, Error> Parser<Lexer>::parseMultiplicativeExpressionPostUnary(AST::Expression::Ref&& lhs)
{
START_PARSE();
while (canContinueMultiplicativeExpression(current())) {
auto op = AST::BinaryOperation::Multiply;
switch (current().m_type) {
case TokenType::Modulo:
op = AST::BinaryOperation::Modulo;
break;
case TokenType::Slash:
op = AST::BinaryOperation::Divide;
break;
case TokenType::Star:
op = AST::BinaryOperation::Multiply;
break;
default:
RELEASE_ASSERT_NOT_REACHED();
}
consume();
PARSE(rhs, UnaryExpression);
lhs = MAKE_NODE_UNIQUE_REF(BinaryExpression, WTFMove(lhs), WTFMove(rhs), op);
}
return WTFMove(lhs);
}
template<typename Lexer>
Expected<UniqueRef<AST::Expression>, Error> Parser<Lexer>::parseUnaryExpression()
{
START_PARSE();
if (current().m_type == TokenType::Minus) {
consume();
PARSE(expression, SingularExpression);
RETURN_NODE_UNIQUE_REF(UnaryExpression, WTFMove(expression), AST::UnaryOperation::Negate);
}
return parseSingularExpression();
}
template<typename Lexer>
Expected<UniqueRef<AST::Expression>, Error> Parser<Lexer>::parseSingularExpression()
{
START_PARSE();
PARSE(base, PrimaryExpression);
return parsePostfixExpression(WTFMove(base), _startOfElementPosition);
}
template<typename Lexer>
Expected<UniqueRef<AST::Expression>, Error> Parser<Lexer>::parsePostfixExpression(UniqueRef<AST::Expression>&& base, SourcePosition startPosition)
{
START_PARSE();
UniqueRef<AST::Expression> expr = WTFMove(base);
// FIXME: add the case for array/vector/matrix access
for (;;) {
switch (current().m_type) {
case TokenType::BracketLeft: {
consume();
PARSE(arrayIndex, Expression);
CONSUME_TYPE(BracketRight);
// FIXME: Replace with NODE_REF(...)
SourceSpan span(startPosition, m_lexer.currentPosition());
expr = makeUniqueRef<AST::IndexAccessExpression>(span, WTFMove(expr), WTFMove(arrayIndex));
break;
}
case TokenType::Period: {
consume();
PARSE(fieldName, Identifier);
// FIXME: Replace with NODE_REF(...)
SourceSpan span(startPosition, m_lexer.currentPosition());
expr = makeUniqueRef<AST::FieldAccessExpression>(span, WTFMove(expr), WTFMove(fieldName));
break;
}
default:
return { WTFMove(expr) };
}
}
}
// https://gpuweb.github.io/gpuweb/wgsl/#syntax-primary_expression
// primary_expression:
// | ident
// | callable argument_expression_list
// | const_literal
// | paren_expression
// | bitcast less_than type_decl greater_than paren_expression
template<typename Lexer>
Expected<UniqueRef<AST::Expression>, Error> Parser<Lexer>::parsePrimaryExpression()
{
START_PARSE();
switch (current().m_type) {
// paren_expression
case TokenType::ParenLeft: {
consume();
PARSE(expr, Expression);
CONSUME_TYPE(ParenRight);
return { WTFMove(expr) };
}
case TokenType::Identifier: {
PARSE(ident, Identifier);
if (current().m_type == TokenType::Lt || current().m_type == TokenType::ParenLeft) {
PARSE(type, TypeNameAfterIdentifier, WTFMove(ident), _startOfElementPosition);
PARSE(arguments, ArgumentExpressionList);
RETURN_NODE_UNIQUE_REF(CallExpression, WTFMove(type), WTFMove(arguments));
}
RETURN_NODE_UNIQUE_REF(IdentifierExpression, WTFMove(ident));
}
case TokenType::KeywordArray: {
PARSE(arrayType, ArrayType);
PARSE(arguments, ArgumentExpressionList);
RETURN_NODE_UNIQUE_REF(CallExpression, WTFMove(arrayType), WTFMove(arguments));
}
// const_literal
case TokenType::LiteralTrue:
consume();
RETURN_NODE_UNIQUE_REF(BoolLiteral, true);
case TokenType::LiteralFalse:
consume();
RETURN_NODE_UNIQUE_REF(BoolLiteral, false);
case TokenType::IntegerLiteral: {
CONSUME_TYPE_NAMED(lit, IntegerLiteral);
RETURN_NODE_UNIQUE_REF(AbstractIntegerLiteral, lit.m_literalValue);
}
case TokenType::IntegerLiteralSigned: {
CONSUME_TYPE_NAMED(lit, IntegerLiteralSigned);
RETURN_NODE_UNIQUE_REF(Signed32Literal, lit.m_literalValue);
}
case TokenType::IntegerLiteralUnsigned: {
CONSUME_TYPE_NAMED(lit, IntegerLiteralUnsigned);
RETURN_NODE_UNIQUE_REF(Unsigned32Literal, lit.m_literalValue);
}
case TokenType::DecimalFloatLiteral: {
CONSUME_TYPE_NAMED(lit, DecimalFloatLiteral);
RETURN_NODE_UNIQUE_REF(AbstractFloatLiteral, lit.m_literalValue);
}
case TokenType::HexFloatLiteral: {
CONSUME_TYPE_NAMED(lit, HexFloatLiteral);
RETURN_NODE_UNIQUE_REF(AbstractFloatLiteral, lit.m_literalValue);
}
// TODO: bitcast expression
default:
break;
}
FAIL("Expected one of '(', a literal, or an identifier"_s);
}
template<typename Lexer>
Expected<UniqueRef<AST::Expression>, Error> Parser<Lexer>::parseExpression()
{
// FIXME: Fill in
PARSE(lhs, UnaryExpression);
return parseRelationalExpressionPostUnary(WTFMove(lhs));
}
template<typename Lexer>
Expected<UniqueRef<AST::Expression>, Error> Parser<Lexer>::parseLHSExpression()
{
START_PARSE();
// FIXME: Add the possibility of a prefix
PARSE(base, CoreLHSExpression);
return parsePostfixExpression(WTFMove(base), _startOfElementPosition);
}
template<typename Lexer>
Expected<UniqueRef<AST::Expression>, Error> Parser<Lexer>::parseCoreLHSExpression()
{
START_PARSE();
switch (current().m_type) {
case TokenType::ParenLeft: {
consume();
PARSE(expr, LHSExpression);
CONSUME_TYPE(ParenRight);
return { WTFMove(expr) };
}
case TokenType::Identifier: {
PARSE(ident, Identifier);
RETURN_NODE_UNIQUE_REF(IdentifierExpression, WTFMove(ident));
}
default:
break;
}
FAIL("Tried to parse the left-hand side of an assignment and failed"_s);
}
template<typename Lexer>
Expected<AST::Expression::List, Error> Parser<Lexer>::parseArgumentExpressionList()
{
START_PARSE();
CONSUME_TYPE(ParenLeft);
AST::Expression::List arguments;
while (current().m_type != TokenType::ParenRight) {
PARSE(expr, Expression);
arguments.append(WTFMove(expr));
if (current().m_type != TokenType::ParenRight) {
CONSUME_TYPE(Comma);
}
}
CONSUME_TYPE(ParenRight);
return { WTFMove(arguments) };
}
} // namespace WGSL