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skia / skia / refs/heads/main / . / src / sksl / SkSLParser.cpp
blob: 3e7fdad1d54ce832d1d916fad7bfbe9c1476c5bd [file] [log] [blame]
/*
* Copyright 2021 Google LLC.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "src/sksl/SkSLParser.h"
#include "include/core/SkSpan.h"
#include "include/private/base/SkTArray.h"
#include "include/sksl/SkSLVersion.h"
#include "src/base/SkEnumBitMask.h"
#include "src/base/SkNoDestructor.h"
#include "src/core/SkTHash.h"
#include "src/sksl/SkSLBuiltinTypes.h"
#include "src/sksl/SkSLCompiler.h"
#include "src/sksl/SkSLConstantFolder.h"
#include "src/sksl/SkSLContext.h"
#include "src/sksl/SkSLErrorReporter.h"
#include "src/sksl/SkSLOperator.h"
#include "src/sksl/SkSLString.h"
#include "src/sksl/ir/SkSLBinaryExpression.h"
#include "src/sksl/ir/SkSLBlock.h"
#include "src/sksl/ir/SkSLBreakStatement.h"
#include "src/sksl/ir/SkSLContinueStatement.h"
#include "src/sksl/ir/SkSLDiscardStatement.h"
#include "src/sksl/ir/SkSLDoStatement.h"
#include "src/sksl/ir/SkSLExpression.h"
#include "src/sksl/ir/SkSLExpressionStatement.h"
#include "src/sksl/ir/SkSLExtension.h"
#include "src/sksl/ir/SkSLFieldAccess.h"
#include "src/sksl/ir/SkSLForStatement.h"
#include "src/sksl/ir/SkSLFunctionCall.h"
#include "src/sksl/ir/SkSLFunctionDeclaration.h"
#include "src/sksl/ir/SkSLFunctionDefinition.h"
#include "src/sksl/ir/SkSLFunctionPrototype.h"
#include "src/sksl/ir/SkSLIfStatement.h"
#include "src/sksl/ir/SkSLIndexExpression.h"
#include "src/sksl/ir/SkSLInterfaceBlock.h"
#include "src/sksl/ir/SkSLLayout.h"
#include "src/sksl/ir/SkSLLiteral.h"
#include "src/sksl/ir/SkSLModifierFlags.h"
#include "src/sksl/ir/SkSLModifiersDeclaration.h"
#include "src/sksl/ir/SkSLNop.h"
#include "src/sksl/ir/SkSLPoison.h"
#include "src/sksl/ir/SkSLPostfixExpression.h"
#include "src/sksl/ir/SkSLPrefixExpression.h"
#include "src/sksl/ir/SkSLProgram.h"
#include "src/sksl/ir/SkSLProgramElement.h"
#include "src/sksl/ir/SkSLReturnStatement.h"
#include "src/sksl/ir/SkSLStatement.h"
#include "src/sksl/ir/SkSLStructDefinition.h"
#include "src/sksl/ir/SkSLSwitchStatement.h"
#include "src/sksl/ir/SkSLSwizzle.h"
#include "src/sksl/ir/SkSLSymbol.h"
#include "src/sksl/ir/SkSLSymbolTable.h"
#include "src/sksl/ir/SkSLTernaryExpression.h"
#include "src/sksl/ir/SkSLType.h"
#include "src/sksl/ir/SkSLTypeReference.h"
#include "src/sksl/ir/SkSLVarDeclarations.h"
#include "src/sksl/ir/SkSLVariable.h"
#include <algorithm>
#include <climits>
#include <initializer_list>
#include <memory>
#include <utility>
#include <vector>
using namespace skia_private;
namespace SkSL {
static constexpr int kMaxParseDepth = 50;
static ModifierFlags parse_modifier_token(Token::Kind token) {
switch (token) {
case Token::Kind::TK_UNIFORM: return ModifierFlag::kUniform;
case Token::Kind::TK_CONST: return ModifierFlag::kConst;
case Token::Kind::TK_IN: return ModifierFlag::kIn;
case Token::Kind::TK_OUT: return ModifierFlag::kOut;
case Token::Kind::TK_INOUT: return ModifierFlag::kIn | ModifierFlag::kOut;
case Token::Kind::TK_FLAT: return ModifierFlag::kFlat;
case Token::Kind::TK_NOPERSPECTIVE: return ModifierFlag::kNoPerspective;
case Token::Kind::TK_PURE: return ModifierFlag::kPure;
case Token::Kind::TK_INLINE: return ModifierFlag::kInline;
case Token::Kind::TK_NOINLINE: return ModifierFlag::kNoInline;
case Token::Kind::TK_HIGHP: return ModifierFlag::kHighp;
case Token::Kind::TK_MEDIUMP: return ModifierFlag::kMediump;
case Token::Kind::TK_LOWP: return ModifierFlag::kLowp;
case Token::Kind::TK_EXPORT: return ModifierFlag::kExport;
case Token::Kind::TK_ES3: return ModifierFlag::kES3;
case Token::Kind::TK_WORKGROUP: return ModifierFlag::kWorkgroup;
case Token::Kind::TK_READONLY: return ModifierFlag::kReadOnly;
case Token::Kind::TK_WRITEONLY: return ModifierFlag::kWriteOnly;
case Token::Kind::TK_BUFFER: return ModifierFlag::kBuffer;
case Token::Kind::TK_PIXELLOCAL: return ModifierFlag::kPixelLocal;
default: return ModifierFlag::kNone;
}
}
class Parser::AutoDepth {
public:
AutoDepth(Parser* p) : fParser(p), fDepth(0) {}
~AutoDepth() {
fParser->fDepth -= fDepth;
}
bool increase() {
++fDepth;
++fParser->fDepth;
if (fParser->fDepth > kMaxParseDepth) {
fParser->error(fParser->peek(), "exceeded max parse depth");
fParser->fEncounteredFatalError = true;
return false;
}
return true;
}
private:
Parser* fParser;
int fDepth;
};
class Parser::AutoSymbolTable {
public:
AutoSymbolTable(Parser* p, std::unique_ptr<SymbolTable>* newSymbolTable, bool enable = true) {
if (enable) {
fParser = p;
SymbolTable*& ctxSymbols = this->contextSymbolTable();
*newSymbolTable = std::make_unique<SymbolTable>(ctxSymbols, ctxSymbols->isBuiltin());
ctxSymbols = newSymbolTable->get();
}
}
~AutoSymbolTable() {
if (fParser) {
SymbolTable*& ctxSymbols = this->contextSymbolTable();
ctxSymbols = ctxSymbols->fParent;
}
}
private:
SymbolTable*& contextSymbolTable() { return fParser->fCompiler.context().fSymbolTable; }
Parser* fParser = nullptr;
};
class Parser::Checkpoint {
public:
Checkpoint(Parser* p) : fParser(p) {
Context& context = fParser->fCompiler.context();
fPushbackCheckpoint = fParser->fPushback;
fLexerCheckpoint = fParser->fLexer.getCheckpoint();
fOldErrorReporter = context.fErrors;
fOldEncounteredFatalError = fParser->fEncounteredFatalError;
SkASSERT(fOldErrorReporter);
context.setErrorReporter(&fErrorReporter);
}
~Checkpoint() {
SkASSERTF(!fOldErrorReporter, "Checkpoint was not accepted or rewound before destruction");
}
void accept() {
this->restoreErrorReporter();
// Parser errors should have been fatal, but we can encounter other errors like type
// mismatches despite accepting the parse. Forward those messages to the actual error
// handler now.
fErrorReporter.forwardErrors(fParser);
}
void rewind() {
this->restoreErrorReporter();
fParser->fPushback = fPushbackCheckpoint;
fParser->fLexer.rewindToCheckpoint(fLexerCheckpoint);
fParser->fEncounteredFatalError = fOldEncounteredFatalError;
}
private:
class ForwardingErrorReporter : public ErrorReporter {
public:
void handleError(std::string_view msg, Position pos) override {
fErrors.push_back({std::string(msg), pos});
}
void forwardErrors(Parser* parser) {
for (const Error& error : fErrors) {
parser->error(error.fPos, error.fMsg);
}
}
private:
struct Error {
std::string fMsg;
Position fPos;
};
skia_private::TArray<Error> fErrors;
};
void restoreErrorReporter() {
SkASSERT(fOldErrorReporter);
fParser->fCompiler.context().setErrorReporter(fOldErrorReporter);
fOldErrorReporter = nullptr;
}
Parser* fParser;
Token fPushbackCheckpoint;
SkSL::Lexer::Checkpoint fLexerCheckpoint;
ForwardingErrorReporter fErrorReporter;
ErrorReporter* fOldErrorReporter;
bool fOldEncounteredFatalError;
};
Parser::Parser(Compiler* compiler,
const ProgramSettings& settings,
ProgramKind kind,
std::unique_ptr<std::string> text)
: fCompiler(*compiler)
, fSettings(settings)
, fKind(kind)
, fText(std::move(text))
, fPushback(Token::Kind::TK_NONE, /*offset=*/-1, /*length=*/-1) {
fLexer.start(*fText);
}
Parser::~Parser() = default;
SymbolTable* Parser::symbolTable() {
return fCompiler.symbolTable();
}
Token Parser::nextRawToken() {
Token token;
if (fPushback.fKind != Token::Kind::TK_NONE) {
// Retrieve the token from the pushback buffer.
token = fPushback;
fPushback.fKind = Token::Kind::TK_NONE;
} else {
// Fetch a token from the lexer.
token = fLexer.next();
// Some tokens are always invalid, so we detect and report them here.
switch (token.fKind) {
case Token::Kind::TK_PRIVATE_IDENTIFIER:
if (ProgramConfig::AllowsPrivateIdentifiers(fKind)) {
token.fKind = Token::Kind::TK_IDENTIFIER;
break;
}
[[fallthrough]];
case Token::Kind::TK_RESERVED:
this->error(token, "name '" + std::string(this->text(token)) + "' is reserved");
token.fKind = Token::Kind::TK_IDENTIFIER; // reduces additional follow-up errors
break;
case Token::Kind::TK_BAD_OCTAL:
this->error(token, "'" + std::string(this->text(token)) +
"' is not a valid octal number");
break;
default:
break;
}
}
return token;
}
static bool is_whitespace(Token::Kind kind) {
switch (kind) {
case Token::Kind::TK_WHITESPACE:
case Token::Kind::TK_LINE_COMMENT:
case Token::Kind::TK_BLOCK_COMMENT:
return true;
default:
return false;
}
}
bool Parser::expectNewline() {
Token token = this->nextRawToken();
if (token.fKind == Token::Kind::TK_WHITESPACE) {
// The lexer doesn't distinguish newlines from other forms of whitespace, so we check
// for newlines by searching through the token text.
std::string_view tokenText = this->text(token);
if (tokenText.find_first_of('\r') != std::string_view::npos ||
tokenText.find_first_of('\n') != std::string_view::npos) {
return true;
}
}
// We didn't find a newline.
this->pushback(token);
return false;
}
Token Parser::nextToken() {
for (;;) {
Token token = this->nextRawToken();
if (!is_whitespace(token.fKind)) {
return token;
}
}
}
void Parser::pushback(Token t) {
SkASSERT(fPushback.fKind == Token::Kind::TK_NONE);
fPushback = t;
}
Token Parser::peek() {
if (fPushback.fKind == Token::Kind::TK_NONE) {
fPushback = this->nextToken();
}
return fPushback;
}
bool Parser::checkNext(Token::Kind kind, Token* result) {
if (fPushback.fKind != Token::Kind::TK_NONE && fPushback.fKind != kind) {
return false;
}
Token next = this->nextToken();
if (next.fKind == kind) {
if (result) {
*result = next;
}
return true;
}
this->pushback(next);
return false;
}
bool Parser::expect(Token::Kind kind, const char* expected, Token* result) {
Token next = this->nextToken();
if (next.fKind == kind) {
if (result) {
*result = next;
}
return true;
} else {
this->error(next, "expected " + std::string(expected) + ", but found '" +
std::string(this->text(next)) + "'");
this->fEncounteredFatalError = true;
return false;
}
}
bool Parser::expectIdentifier(Token* result) {
if (!this->expect(Token::Kind::TK_IDENTIFIER, "an identifier", result)) {
return false;
}
if (this->symbolTable()->isBuiltinType(this->text(*result))) {
this->error(*result, "expected an identifier, but found type '" +
std::string(this->text(*result)) + "'");
this->fEncounteredFatalError = true;
return false;
}
return true;
}
bool Parser::checkIdentifier(Token* result) {
if (!this->checkNext(Token::Kind::TK_IDENTIFIER, result)) {
return false;
}
if (this->symbolTable()->isBuiltinType(this->text(*result))) {
this->pushback(*result);
return false;
}
return true;
}
std::string_view Parser::text(Token token) {
return std::string_view(fText->data() + token.fOffset, token.fLength);
}
Position Parser::position(Token t) {
if (t.fOffset >= 0) {
return Position::Range(t.fOffset, t.fOffset + t.fLength);
} else {
return Position();
}
}
void Parser::error(Token token, std::string_view msg) {
this->error(this->position(token), msg);
}
void Parser::error(Position position, std::string_view msg) {
fCompiler.context().fErrors->error(position, msg);
}
Position Parser::rangeFrom(Position start) {
int offset = fPushback.fKind != Token::Kind::TK_NONE ? fPushback.fOffset
: fLexer.getCheckpoint().fOffset;
return Position::Range(start.startOffset(), offset);
}
Position Parser::rangeFrom(Token start) {
return this->rangeFrom(this->position(start));
}
/* declaration* END_OF_FILE */
std::unique_ptr<Program> Parser::programInheritingFrom(const SkSL::Module* module) {
this->declarations();
std::unique_ptr<Program> result;
if (fCompiler.errorReporter().errorCount() == 0) {
result = fCompiler.releaseProgram(std::move(fText), std::move(fProgramElements));
} else {
fProgramElements.clear();
}
return result;
}
std::unique_ptr<SkSL::Module> Parser::moduleInheritingFrom(const SkSL::Module* parentModule) {
this->declarations();
this->symbolTable()->takeOwnershipOfString(std::move(*fText));
auto result = std::make_unique<SkSL::Module>();
result->fParent = parentModule;
result->fSymbols = std::move(fCompiler.fGlobalSymbols);
result->fElements = std::move(fProgramElements);
return result;
}
void Parser::declarations() {
fEncounteredFatalError = false;
// If the program is 8MB or longer (Position::kMaxOffset), error reporting goes off the rails.
// At any rate, there's no good reason for a program to be this long.
if (fText->size() >= Position::kMaxOffset) {
this->error(Position(), "program is too large");
return;
}
// Any #version directive must appear as the first thing in a file
if (this->peek().fKind == Token::Kind::TK_DIRECTIVE) {
this->directive(/*allowVersion=*/true);
}
while (!fEncounteredFatalError) {
// We should always be at global scope when processing top-level declarations.
SkASSERT(fCompiler.context().fSymbolTable == fCompiler.globalSymbols());
switch (this->peek().fKind) {
case Token::Kind::TK_END_OF_FILE:
return;
case Token::Kind::TK_INVALID:
this->error(this->peek(), "invalid token");
return;
case Token::Kind::TK_DIRECTIVE:
this->directive(/*allowVersion=*/false);
break;
default:
this->declaration();
break;
}
}
}
/* DIRECTIVE(#extension) IDENTIFIER COLON IDENTIFIER NEWLINE */
void Parser::extensionDirective(Position start) {
Token name;
if (!this->expectIdentifier(&name)) {
return;
}
if (!this->expect(Token::Kind::TK_COLON, "':'")) {
return;
}
Token behavior;
if (!this->expect(Token::Kind::TK_IDENTIFIER, "an identifier", &behavior)) {
return;
}
// We expect a newline immediately after `#extension name : behavior`.
if (this->expectNewline()) {
std::unique_ptr<SkSL::Extension> ext = Extension::Convert(fCompiler.context(),
this->rangeFrom(start),
this->text(name),
this->text(behavior));
if (ext) {
fProgramElements.push_back(std::move(ext));
}
} else {
this->error(start, "invalid #extension directive");
}
}
/* DIRECTIVE(#version) INTLITERAL NEWLINE */
void Parser::versionDirective(Position start, bool allowVersion) {
if (!allowVersion) {
this->error(start, "#version directive must appear before anything else");
return;
}
SKSL_INT version;
if (!this->intLiteral(&version)) {
return;
}
switch (version) {
case 100:
fCompiler.context().fConfig->fRequiredSkSLVersion = Version::k100;
break;
case 300:
fCompiler.context().fConfig->fRequiredSkSLVersion = Version::k300;
break;
default:
this->error(start, "unsupported version number");
return;
}
// We expect a newline after a #version directive.
if (!this->expectNewline()) {
this->error(start, "invalid #version directive");
}
}
/* DIRECTIVE(#extension) IDENTIFIER COLON IDENTIFIER NEWLINE |
DIRECTIVE(#version) INTLITERAL NEWLINE */
void Parser::directive(bool allowVersion) {
Token start;
if (!this->expect(Token::Kind::TK_DIRECTIVE, "a directive", &start)) {
return;
}
std::string_view text = this->text(start);
if (text == "#extension") {
return this->extensionDirective(this->position(start));
}
if (text == "#version") {
return this->versionDirective(this->position(start), allowVersion);
}
this->error(start, "unsupported directive '" + std::string(this->text(start)) + "'");
}
bool Parser::modifiersDeclarationEnd(const SkSL::Modifiers& mods) {
std::unique_ptr<ModifiersDeclaration> decl = ModifiersDeclaration::Convert(fCompiler.context(),
mods);
if (!decl) {
return false;
}
fProgramElements.push_back(std::move(decl));
return true;
}
/* modifiers (structVarDeclaration | type IDENTIFIER ((LPAREN parameter (COMMA parameter)* RPAREN
(block | SEMICOLON)) | SEMICOLON) | interfaceBlock) */
bool Parser::declaration() {
Token start = this->peek();
if (start.fKind == Token::Kind::TK_SEMICOLON) {
this->nextToken();
this->error(start, "expected a declaration, but found ';'");
return false;
}
Modifiers modifiers = this->modifiers();
Token lookahead = this->peek();
if (lookahead.fKind == Token::Kind::TK_IDENTIFIER &&
!this->symbolTable()->isType(this->text(lookahead))) {
// we have an identifier that's not a type, could be the start of an interface block
return this->interfaceBlock(modifiers);
}
if (lookahead.fKind == Token::Kind::TK_SEMICOLON) {
this->nextToken();
return this->modifiersDeclarationEnd(modifiers);
}
if (lookahead.fKind == Token::Kind::TK_STRUCT) {
this->structVarDeclaration(this->position(start), modifiers);
return true;
}
const Type* type = this->type(&modifiers);
if (!type) {
return false;
}
Token name;
if (!this->expectIdentifier(&name)) {
return false;
}
if (this->checkNext(Token::Kind::TK_LPAREN)) {
return this->functionDeclarationEnd(this->position(start), modifiers, type, name);
} else {
this->globalVarDeclarationEnd(this->position(start), modifiers, type, name);
return true;
}
}
/* (RPAREN | VOID RPAREN | parameter (COMMA parameter)* RPAREN) (block | SEMICOLON) */
bool Parser::functionDeclarationEnd(Position start,
Modifiers& modifiers,
const Type* returnType,
const Token& name) {
Token lookahead = this->peek();
bool validParams = true;
STArray<8, std::unique_ptr<Variable>> parameters;
if (lookahead.fKind == Token::Kind::TK_RPAREN) {
// `()` means no parameters at all.
} else if (lookahead.fKind == Token::Kind::TK_IDENTIFIER && this->text(lookahead) == "void") {
// `(void)` also means no parameters at all.
this->nextToken();
} else {
for (;;) {
std::unique_ptr<SkSL::Variable> param;
if (!this->parameter(&param)) {
return false;
}
validParams = validParams && param;
parameters.push_back(std::move(param));
if (!this->checkNext(Token::Kind::TK_COMMA)) {
break;
}
}
}
if (!this->expect(Token::Kind::TK_RPAREN, "')'")) {
return false;
}
SkSL::FunctionDeclaration* decl = nullptr;
if (validParams) {
decl = SkSL::FunctionDeclaration::Convert(fCompiler.context(),
this->rangeFrom(start),
modifiers,
this->text(name),
std::move(parameters),
start,
returnType);
}
if (this->checkNext(Token::Kind::TK_SEMICOLON)) {
return this->prototypeFunction(decl);
} else {
return this->defineFunction(decl);
}
}
bool Parser::prototypeFunction(SkSL::FunctionDeclaration* decl) {
if (!decl) {
return false;
}
fProgramElements.push_back(std::make_unique<SkSL::FunctionPrototype>(
decl->fPosition, decl, fCompiler.context().fConfig->fIsBuiltinCode));
return true;
}
bool Parser::defineFunction(SkSL::FunctionDeclaration* decl) {
const Context& context = fCompiler.context();
Token bodyStart = this->peek();
std::unique_ptr<SymbolTable> symbolTable;
std::unique_ptr<Statement> body;
{
// Create a symbol table for the function which includes the parameters.
AutoSymbolTable symbols(this, &symbolTable);
if (decl) {
for (Variable* param : decl->parameters()) {
symbolTable->addWithoutOwnership(fCompiler.context(), param);
}
}
// Parse the function body.
body = this->block(/*introduceNewScope=*/false, /*adoptExistingSymbolTable=*/&symbolTable);
}
// If there was a problem with the declarations or body, don't actually create a definition.
if (!decl || !body) {
return false;
}
std::unique_ptr<SkSL::Statement> block = std::move(body);
SkASSERT(block->is<Block>());
Position pos = this->rangeFrom(bodyStart);
block->fPosition = pos;
std::unique_ptr<FunctionDefinition> function = FunctionDefinition::Convert(context,
pos,
*decl,
std::move(block),
/*builtin=*/false);
if (!function) {
return false;
}
decl->setDefinition(function.get());
fProgramElements.push_back(std::move(function));
return true;
}
bool Parser::arraySize(SKSL_INT* outResult) {
// Start out with a safe value that won't generate any errors downstream
*outResult = 1;
Token next = this->peek();
if (next.fKind == Token::Kind::TK_RBRACKET) {
this->error(this->position(next), "unsized arrays are not permitted here");
return true;
}
std::unique_ptr<Expression> sizeLiteral = this->expression();
if (!sizeLiteral) {
return false;
}
if (!sizeLiteral->is<Poison>()) {
SKSL_INT size;
if (!ConstantFolder::GetConstantInt(*sizeLiteral, &size)) {
this->error(sizeLiteral->fPosition, "array size must be an integer");
return true;
}
if (size > INT32_MAX) {
this->error(sizeLiteral->fPosition, "array size out of bounds");
return true;
}
if (size <= 0) {
this->error(sizeLiteral->fPosition, "array size must be positive");
return true;
}
// Now that we've validated it, output the real value
*outResult = size;
}
return true;
}
const Type* Parser::arrayType(const Type* base, int count, Position pos) {
const Context& context = fCompiler.context();
count = base->convertArraySize(context, pos, pos, count);
if (!count) {
return context.fTypes.fPoison.get();
}
return this->symbolTable()->addArrayDimension(fCompiler.context(), base, count);
}
const Type* Parser::unsizedArrayType(const Type* base, Position pos) {
const Context& context = fCompiler.context();
if (!base->checkIfUsableInArray(context, pos)) {
return context.fTypes.fPoison.get();
}
return this->symbolTable()->addArrayDimension(fCompiler.context(), base,
SkSL::Type::kUnsizedArray);
}
bool Parser::parseArrayDimensions(Position pos, const Type** type) {
Token next;
while (this->checkNext(Token::Kind::TK_LBRACKET, &next)) {
if (this->checkNext(Token::Kind::TK_RBRACKET)) {
if (this->allowUnsizedArrays()) {
*type = this->unsizedArrayType(*type, this->rangeFrom(pos));
} else {
this->error(this->rangeFrom(pos), "unsized arrays are not permitted here");
}
} else {
SKSL_INT size;
if (!this->arraySize(&size)) {
return false;
}
if (!this->expect(Token::Kind::TK_RBRACKET, "']'")) {
return false;
}
*type = this->arrayType(*type, size, this->rangeFrom(pos));
}
}
return true;
}
bool Parser::parseInitializer(Position pos, std::unique_ptr<Expression>* initializer) {
if (this->checkNext(Token::Kind::TK_EQ)) {
*initializer = this->assignmentExpression();
return *initializer != nullptr;
}
return true;
}
void Parser::addGlobalVarDeclaration(std::unique_ptr<VarDeclaration> decl) {
if (decl) {
fProgramElements.push_back(std::make_unique<SkSL::GlobalVarDeclaration>(std::move(decl)));
}
}
/* (LBRACKET expression? RBRACKET)* (EQ assignmentExpression)? (COMMA IDENTIFER
(LBRACKET expression? RBRACKET)* (EQ assignmentExpression)?)* SEMICOLON */
void Parser::globalVarDeclarationEnd(Position pos,
const Modifiers& mods,
const Type* baseType,
Token name) {
const Type* type = baseType;
std::unique_ptr<Expression> initializer;
if (!this->parseArrayDimensions(pos, &type)) {
return;
}
if (!this->parseInitializer(pos, &initializer)) {
return;
}
this->addGlobalVarDeclaration(VarDeclaration::Convert(fCompiler.context(),
this->rangeFrom(pos),
mods,
*type,
this->position(name),
this->text(name),
VariableStorage::kGlobal,
std::move(initializer)));
while (this->checkNext(Token::Kind::TK_COMMA)) {
type = baseType;
Token identifierName;
if (!this->expectIdentifier(&identifierName)) {
return;
}
if (!this->parseArrayDimensions(pos, &type)) {
return;
}
std::unique_ptr<Expression> anotherInitializer;
if (!this->parseInitializer(pos, &anotherInitializer)) {
return;
}
this->addGlobalVarDeclaration(VarDeclaration::Convert(fCompiler.context(),
this->rangeFrom(identifierName),
mods,
*type,
this->position(identifierName),
this->text(identifierName),
VariableStorage::kGlobal,
std::move(anotherInitializer)));
}
this->expect(Token::Kind::TK_SEMICOLON, "';'");
}
/* (LBRACKET expression? RBRACKET)* (EQ assignmentExpression)? (COMMA IDENTIFER
(LBRACKET expression? RBRACKET)* (EQ assignmentExpression)?)* SEMICOLON */
std::unique_ptr<Statement> Parser::localVarDeclarationEnd(Position pos,
const Modifiers& mods,
const Type* baseType,
Token name) {
const Type* type = baseType;
std::unique_ptr<Expression> initializer;
if (!this->parseArrayDimensions(pos, &type)) {
return nullptr;
}
if (!this->parseInitializer(pos, &initializer)) {
return nullptr;
}
std::unique_ptr<Statement> result = VarDeclaration::Convert(fCompiler.context(),
this->rangeFrom(pos),
mods,
*type,
this->position(name),
this->text(name),
VariableStorage::kLocal,
std::move(initializer));
for (;;) {
if (!this->checkNext(Token::Kind::TK_COMMA)) {
this->expect(Token::Kind::TK_SEMICOLON, "';'");
break;
}
type = baseType;
Token identifierName;
if (!this->expectIdentifier(&identifierName)) {
break;
}
if (!this->parseArrayDimensions(pos, &type)) {
break;
}
std::unique_ptr<Expression> anotherInitializer;
if (!this->parseInitializer(pos, &anotherInitializer)) {
break;
}
std::unique_ptr<Statement> next = VarDeclaration::Convert(fCompiler.context(),
this->rangeFrom(identifierName),
mods,
*type,
this->position(identifierName),
this->text(identifierName),
VariableStorage::kLocal,
std::move(anotherInitializer));
result = Block::MakeCompoundStatement(std::move(result), std::move(next));
}
pos = this->rangeFrom(pos);
return this->statementOrNop(pos, std::move(result));
}
/* (varDeclarations | expressionStatement) */
std::unique_ptr<Statement> Parser::varDeclarationsOrExpressionStatement() {
Token nextToken = this->peek();
if (nextToken.fKind == Token::Kind::TK_CONST) {
// Statements that begin with `const` might be variable declarations, but can't be legal
// SkSL expression-statements. (SkSL constructors don't take a `const` modifier.)
return this->varDeclarations();
}
if (nextToken.fKind == Token::Kind::TK_HIGHP ||
nextToken.fKind == Token::Kind::TK_MEDIUMP ||
nextToken.fKind == Token::Kind::TK_LOWP ||
this->symbolTable()->isType(this->text(nextToken))) {
// Statements that begin with a typename are most often variable declarations, but
// occasionally the type is part of a constructor, and these are actually expression-
// statements in disguise. First, attempt the common case: parse it as a vardecl.
Checkpoint checkpoint(this);
VarDeclarationsPrefix prefix;
if (this->varDeclarationsPrefix(&prefix)) {
checkpoint.accept();
return this->localVarDeclarationEnd(prefix.fPosition, prefix.fModifiers, prefix.fType,
prefix.fName);
}
// If this statement wasn't actually a vardecl after all, rewind and try parsing it as an
// expression-statement instead.
checkpoint.rewind();
}
return this->expressionStatement();
}
// Helper function for varDeclarations(). If this function succeeds, we assume that the rest of the
// statement is a variable-declaration statement, not an expression-statement.
bool Parser::varDeclarationsPrefix(VarDeclarationsPrefix* prefixData) {
prefixData->fPosition = this->position(this->peek());
prefixData->fModifiers = this->modifiers();
prefixData->fType = this->type(&prefixData->fModifiers);
if (!prefixData->fType) {
return false;
}
return this->expectIdentifier(&prefixData->fName);
}
/* modifiers type IDENTIFIER varDeclarationEnd */
std::unique_ptr<Statement> Parser::varDeclarations() {
VarDeclarationsPrefix prefix;
if (!this->varDeclarationsPrefix(&prefix)) {
return nullptr;
}
return this->localVarDeclarationEnd(prefix.fPosition, prefix.fModifiers, prefix.fType,
prefix.fName);
}
/* STRUCT IDENTIFIER LBRACE varDeclaration* RBRACE */
const Type* Parser::structDeclaration() {
AutoDepth depth(this);
Position start = this->position(this->peek());
if (!this->expect(Token::Kind::TK_STRUCT, "'struct'")) {
return nullptr;
}
Token name;
if (!this->expectIdentifier(&name)) {
return nullptr;
}
if (!this->expect(Token::Kind::TK_LBRACE, "'{'")) {
return nullptr;
}
if (!depth.increase()) {
return nullptr;
}
TArray<SkSL::Field> fields;
while (!this->checkNext(Token::Kind::TK_RBRACE)) {
Token fieldStart = this->peek();
Modifiers modifiers = this->modifiers();
const Type* type = this->type(&modifiers);
if (!type) {
return nullptr;
}
do {
const Type* actualType = type;
Token memberName;
if (!this->expectIdentifier(&memberName)) {
return nullptr;
}
while (this->checkNext(Token::Kind::TK_LBRACKET)) {
SKSL_INT size;
if (!this->arraySize(&size)) {
return nullptr;
}
if (!this->expect(Token::Kind::TK_RBRACKET, "']'")) {
return nullptr;
}
actualType = this->arrayType(actualType, size,
this->rangeFrom(this->position(fieldStart)));
}
fields.push_back(SkSL::Field(this->rangeFrom(fieldStart),
modifiers.fLayout,
modifiers.fFlags,
this->text(memberName),
actualType));
} while (this->checkNext(Token::Kind::TK_COMMA));
if (!this->expect(Token::Kind::TK_SEMICOLON, "';'")) {
return nullptr;
}
}
std::unique_ptr<SkSL::StructDefinition> def = StructDefinition::Convert(fCompiler.context(),
this->rangeFrom(start),
this->text(name),
std::move(fields));
if (!def) {
return nullptr;
}
const Type* result = &def->type();
fProgramElements.push_back(std::move(def));
return result;
}
/* structDeclaration ((IDENTIFIER varDeclarationEnd) | SEMICOLON) */
void Parser::structVarDeclaration(Position start, const Modifiers& modifiers) {
const Type* type = this->structDeclaration();
if (!type) {
return;
}
Token name;
if (this->checkIdentifier(&name)) {
this->globalVarDeclarationEnd(this->rangeFrom(name), modifiers, type, name);
} else {
this->expect(Token::Kind::TK_SEMICOLON, "';'");
}
}
/* modifiers type IDENTIFIER (LBRACKET INT_LITERAL RBRACKET)? */
bool Parser::parameter(std::unique_ptr<SkSL::Variable>* outParam) {
Position pos = this->position(this->peek());
Modifiers modifiers = this->modifiers();
const Type* type = this->type(&modifiers);
if (!type) {
return false;
}
Token name;
std::string_view nameText;
Position namePos;
if (this->checkIdentifier(&name)) {
nameText = this->text(name);
namePos = this->position(name);
} else {
namePos = this->rangeFrom(pos);
}
if (!this->parseArrayDimensions(pos, &type)) {
return false;
}
*outParam = SkSL::Variable::Convert(fCompiler.context(),
this->rangeFrom(pos),
modifiers.fPosition,
modifiers.fLayout,
modifiers.fFlags,
type,
namePos,
nameText,
VariableStorage::kParameter);
return true;
}
/** EQ INT_LITERAL */
int Parser::layoutInt() {
if (!this->expect(Token::Kind::TK_EQ, "'='")) {
return -1;
}
Token resultToken;
if (!this->expect(Token::Kind::TK_INT_LITERAL, "a non-negative integer", &resultToken)) {
return -1;
}
std::string_view resultFrag = this->text(resultToken);
SKSL_INT resultValue;
if (!SkSL::stoi(resultFrag, &resultValue)) {
this->error(resultToken, "value in layout is too large: " + std::string(resultFrag));
return -1;
}
return resultValue;
}
/** EQ IDENTIFIER */
std::string_view Parser::layoutIdentifier() {
if (!this->expect(Token::Kind::TK_EQ, "'='")) {
return {};
}
Token resultToken;
if (!this->expectIdentifier(&resultToken)) {
return {};
}
return this->text(resultToken);
}
/* LAYOUT LPAREN IDENTIFIER (EQ INT_LITERAL)? (COMMA IDENTIFIER (EQ INT_LITERAL)?)* RPAREN */
SkSL::Layout Parser::layout() {
using LayoutMap = THashMap<std::string_view, SkSL::LayoutFlag>;
static SkNoDestructor<LayoutMap> sLayoutTokens(LayoutMap{
{"location", SkSL::LayoutFlag::kLocation},
{"offset", SkSL::LayoutFlag::kOffset},
{"binding", SkSL::LayoutFlag::kBinding},
{"texture", SkSL::LayoutFlag::kTexture},
{"sampler", SkSL::LayoutFlag::kSampler},
{"index", SkSL::LayoutFlag::kIndex},
{"set", SkSL::LayoutFlag::kSet},
{"builtin", SkSL::LayoutFlag::kBuiltin},
{"input_attachment_index", SkSL::LayoutFlag::kInputAttachmentIndex},
{"origin_upper_left", SkSL::LayoutFlag::kOriginUpperLeft},
{"blend_support_all_equations", SkSL::LayoutFlag::kBlendSupportAllEquations},
{"push_constant", SkSL::LayoutFlag::kPushConstant},
{"color", SkSL::LayoutFlag::kColor},
{"vulkan", SkSL::LayoutFlag::kVulkan},
{"metal", SkSL::LayoutFlag::kMetal},
{"webgpu", SkSL::LayoutFlag::kWebGPU},
{"direct3d", SkSL::LayoutFlag::kDirect3D},
{"rgba8", SkSL::LayoutFlag::kRGBA8},
{"rgba32f", SkSL::LayoutFlag::kRGBA32F},
{"r32f", SkSL::LayoutFlag::kR32F},
{"local_size_x", SkSL::LayoutFlag::kLocalSizeX},
{"local_size_y", SkSL::LayoutFlag::kLocalSizeY},
{"local_size_z", SkSL::LayoutFlag::kLocalSizeZ},
});
Layout result;
if (this->checkNext(Token::Kind::TK_LAYOUT) &&
this->expect(Token::Kind::TK_LPAREN, "'('")) {
for (;;) {
Token t = this->nextToken();
std::string_view text = this->text(t);
SkSL::LayoutFlag* found = sLayoutTokens->find(text);
if (!found) {
this->error(t, "'" + std::string(text) + "' is not a valid layout qualifier");
} else {
if (result.fFlags & *found) {
this->error(t, "layout qualifier '" + std::string(text) +
"' appears more than once");
}
result.fFlags |= *found;
switch (*found) {
case SkSL::LayoutFlag::kLocation:
result.fLocation = this->layoutInt();
break;
case SkSL::LayoutFlag::kOffset:
result.fOffset = this->layoutInt();
break;
case SkSL::LayoutFlag::kBinding:
result.fBinding = this->layoutInt();
break;
case SkSL::LayoutFlag::kIndex:
result.fIndex = this->layoutInt();
break;
case SkSL::LayoutFlag::kSet:
result.fSet = this->layoutInt();
break;
case SkSL::LayoutFlag::kTexture:
result.fTexture = this->layoutInt();
break;
case SkSL::LayoutFlag::kSampler:
result.fSampler = this->layoutInt();
break;
case SkSL::LayoutFlag::kBuiltin:
result.fBuiltin = this->layoutInt();
break;
case SkSL::LayoutFlag::kInputAttachmentIndex:
result.fInputAttachmentIndex = this->layoutInt();
break;
case SkSL::LayoutFlag::kLocalSizeX:
result.fLocalSizeX = this->layoutInt();
break;
case SkSL::LayoutFlag::kLocalSizeY:
result.fLocalSizeY = this->layoutInt();
break;
case SkSL::LayoutFlag::kLocalSizeZ:
result.fLocalSizeZ = this->layoutInt();
break;
default:
break;
}
}
if (this->checkNext(Token::Kind::TK_RPAREN)) {
break;
}
if (!this->expect(Token::Kind::TK_COMMA, "','")) {
break;
}
}
}
return result;
}
/* layout? (UNIFORM | CONST | IN | OUT | INOUT | LOWP | MEDIUMP | HIGHP | FLAT | NOPERSPECTIVE |
VARYING | INLINE | WORKGROUP | READONLY | WRITEONLY | BUFFER)* */
Modifiers Parser::modifiers() {
int start = this->peek().fOffset;
SkSL::Layout layout = this->layout();
Token raw = this->nextRawToken();
int end = raw.fOffset;
if (!is_whitespace(raw.fKind)) {
this->pushback(raw);
}
ModifierFlags flags = ModifierFlag::kNone;
for (;;) {
ModifierFlags tokenFlag = parse_modifier_token(peek().fKind);
if (tokenFlag == ModifierFlag::kNone) {
break;
}
Token modifier = this->nextToken();
if (ModifierFlags duplicateFlags = (tokenFlag & flags)) {
this->error(modifier, "'" + duplicateFlags.description() + "' appears more than once");
}
flags |= tokenFlag;
end = this->position(modifier).endOffset();
}
return Modifiers{Position::Range(start, end), layout, flags};
}
std::unique_ptr<Statement> Parser::statementOrNop(Position pos, std::unique_ptr<Statement> stmt) {
if (!stmt) {
stmt = Nop::Make();
}
if (pos.valid() && !stmt->position().valid()) {
stmt->setPosition(pos);
}
return stmt;
}
/* ifStatement | forStatement | doStatement | whileStatement | block | expression */
std::unique_ptr<Statement> Parser::statement(bool bracesIntroduceNewScope) {
AutoDepth depth(this);
if (!depth.increase()) {
return nullptr;
}
switch (this->peek().fKind) {
case Token::Kind::TK_IF:
return this->ifStatement();
case Token::Kind::TK_FOR:
return this->forStatement();
case Token::Kind::TK_DO:
return this->doStatement();
case Token::Kind::TK_WHILE:
return this->whileStatement();
case Token::Kind::TK_SWITCH:
return this->switchStatement();
case Token::Kind::TK_RETURN:
return this->returnStatement();
case Token::Kind::TK_BREAK:
return this->breakStatement();
case Token::Kind::TK_CONTINUE:
return this->continueStatement();
case Token::Kind::TK_DISCARD:
return this->discardStatement();
case Token::Kind::TK_LBRACE:
return this->block(bracesIntroduceNewScope, /*adoptExistingSymbolTable=*/nullptr);
case Token::Kind::TK_SEMICOLON:
this->nextToken();
return Nop::Make();
case Token::Kind::TK_CONST:
return this->varDeclarations();
case Token::Kind::TK_HIGHP:
case Token::Kind::TK_MEDIUMP:
case Token::Kind::TK_LOWP:
case Token::Kind::TK_IDENTIFIER:
return this->varDeclarationsOrExpressionStatement();
default:
return this->expressionStatement();
}
}
const Type* Parser::findType(Position pos,
Modifiers* modifiers,
std::string_view name) {
const Context& context = fCompiler.context();
const Symbol* symbol = this->symbolTable()->find(name);
if (!symbol) {
this->error(pos, "no symbol named '" + std::string(name) + "'");
return context.fTypes.fPoison.get();
}
if (!symbol->is<Type>()) {
this->error(pos, "symbol '" + std::string(name) + "' is not a type");
return context.fTypes.fPoison.get();
}
const SkSL::Type* type = &symbol->as<Type>();
if (!context.fConfig->fIsBuiltinCode) {
if (!TypeReference::VerifyType(context, type, pos)) {
return context.fTypes.fPoison.get();
}
}
Position qualifierRange = modifiers->fPosition;
if (qualifierRange.startOffset() == qualifierRange.endOffset()) {
qualifierRange = this->rangeFrom(qualifierRange);
}
return modifiers ? type->applyQualifiers(context, &modifiers->fFlags, qualifierRange)
: type;
}
/* IDENTIFIER(type) (LBRACKET intLiteral? RBRACKET)* QUESTION? */
const Type* Parser::type(Modifiers* modifiers) {
Token type;
if (!this->expect(Token::Kind::TK_IDENTIFIER, "a type", &type)) {
return nullptr;
}
if (!this->symbolTable()->isType(this->text(type))) {
this->error(type, "no type named '" + std::string(this->text(type)) + "'");
return fCompiler.context().fTypes.fInvalid.get();
}
const Type* result = this->findType(this->position(type), modifiers, this->text(type));
if (result->isInterfaceBlock()) {
// SkSL puts interface blocks into the symbol table, but they aren't general-purpose types;
// you can't use them to declare a variable type or a function return type.
this->error(type, "expected a type, found '" + std::string(this->text(type)) + "'");
return fCompiler.context().fTypes.fInvalid.get();
}
Token bracket;
while (this->checkNext(Token::Kind::TK_LBRACKET, &bracket)) {
if (this->checkNext(Token::Kind::TK_RBRACKET)) {
if (this->allowUnsizedArrays()) {
result = this->unsizedArrayType(result, this->rangeFrom(type));
} else {
this->error(this->rangeFrom(bracket), "unsized arrays are not permitted here");
}
} else {
SKSL_INT size;
if (!this->arraySize(&size)) {
return nullptr;
}
this->expect(Token::Kind::TK_RBRACKET, "']'");
result = this->arrayType(result, size, this->rangeFrom(type));
}
}
return result;
}
/* IDENTIFIER LBRACE
varDeclaration+
RBRACE (IDENTIFIER (LBRACKET expression RBRACKET)*)? SEMICOLON */
bool Parser::interfaceBlock(const Modifiers& modifiers) {
Token typeName;
if (!this->expectIdentifier(&typeName)) {
return false;
}
if (this->peek().fKind != Token::Kind::TK_LBRACE) {
// we only get into interfaceBlock if we found a top-level identifier which was not a type.
// 99% of the time, the user was not actually intending to create an interface block, so
// it's better to report it as an unknown type
this->error(typeName, "no type named '" + std::string(this->text(typeName)) + "'");
return false;
}
this->nextToken();
TArray<SkSL::Field> fields;
while (!this->checkNext(Token::Kind::TK_RBRACE)) {
Position fieldPos = this->position(this->peek());
Modifiers fieldModifiers = this->modifiers();
const Type* type = this->type(&fieldModifiers);
if (!type) {
return false;
}
do {
Token fieldName;
if (!this->expectIdentifier(&fieldName)) {
return false;
}
const Type* actualType = type;
if (this->checkNext(Token::Kind::TK_LBRACKET)) {
Token sizeToken = this->peek();
if (sizeToken.fKind != Token::Kind::TK_RBRACKET) {
SKSL_INT size;
if (!this->arraySize(&size)) {
return false;
}
actualType = this->arrayType(actualType, size, this->position(typeName));
} else if (this->allowUnsizedArrays()) {
actualType = this->unsizedArrayType(actualType, this->position(typeName));
} else {
this->error(sizeToken, "unsized arrays are not permitted here");
}
this->expect(Token::Kind::TK_RBRACKET, "']'");
}
if (!this->expect(Token::Kind::TK_SEMICOLON, "';'")) {
return false;
}
fields.push_back(SkSL::Field(this->rangeFrom(fieldPos),
fieldModifiers.fLayout,
fieldModifiers.fFlags,
this->text(fieldName),
actualType));
} while (this->checkNext(Token::Kind::TK_COMMA));
}
std::string_view instanceName;
Token instanceNameToken;
SKSL_INT size = 0;
if (this->checkIdentifier(&instanceNameToken)) {
instanceName = this->text(instanceNameToken);
if (this->checkNext(Token::Kind::TK_LBRACKET)) {
if (!this->arraySize(&size)) {
return false;
}
this->expect(Token::Kind::TK_RBRACKET, "']'");
}
}
this->expect(Token::Kind::TK_SEMICOLON, "';'");
if (std::unique_ptr<SkSL::InterfaceBlock> ib = InterfaceBlock::Convert(fCompiler.context(),
this->position(typeName),
modifiers,
this->text(typeName),
std::move(fields),
instanceName,
size)) {
fProgramElements.push_back(std::move(ib));
return true;
}
return false;
}
/* IF LPAREN expression RPAREN statement (ELSE statement)? */
std::unique_ptr<Statement> Parser::ifStatement() {
Token start;
if (!this->expect(Token::Kind::TK_IF, "'if'", &start)) {
return nullptr;
}
if (!this->expect(Token::Kind::TK_LPAREN, "'('")) {
return nullptr;
}
std::unique_ptr<Expression> test = this->expression();
if (!test) {
return nullptr;
}
if (!this->expect(Token::Kind::TK_RPAREN, "')'")) {
return nullptr;
}
std::unique_ptr<Statement> ifTrue = this->statement();
if (!ifTrue) {
return nullptr;
}
std::unique_ptr<Statement> ifFalse;
if (this->checkNext(Token::Kind::TK_ELSE)) {
ifFalse = this->statement();
if (!ifFalse) {
return nullptr;
}
}
Position pos = this->rangeFrom(start);
return this->statementOrNop(pos, IfStatement::Convert(fCompiler.context(),
pos,
std::move(test),
std::move(ifTrue),
std::move(ifFalse)));
}
/* DO statement WHILE LPAREN expression RPAREN SEMICOLON */
std::unique_ptr<Statement> Parser::doStatement() {
Token start;
if (!this->expect(Token::Kind::TK_DO, "'do'", &start)) {
return nullptr;
}
std::unique_ptr<Statement> statement = this->statement();
if (!statement) {
return nullptr;
}
if (!this->expect(Token::Kind::TK_WHILE, "'while'")) {
return nullptr;
}
if (!this->expect(Token::Kind::TK_LPAREN, "'('")) {
return nullptr;
}
std::unique_ptr<Expression> test = this->expression();
if (!test) {
return nullptr;
}
if (!this->expect(Token::Kind::TK_RPAREN, "')'")) {
return nullptr;
}
if (!this->expect(Token::Kind::TK_SEMICOLON, "';'")) {
return nullptr;
}
Position pos = this->rangeFrom(start);
return this->statementOrNop(pos, DoStatement::Convert(fCompiler.context(), pos,
std::move(statement), std::move(test)));
}
/* WHILE LPAREN expression RPAREN STATEMENT */
std::unique_ptr<Statement> Parser::whileStatement() {
Token start;
if (!this->expect(Token::Kind::TK_WHILE, "'while'", &start)) {
return nullptr;
}
if (!this->expect(Token::Kind::TK_LPAREN, "'('")) {
return nullptr;
}
std::unique_ptr<Expression> test = this->expression();
if (!test) {
return nullptr;
}
if (!this->expect(Token::Kind::TK_RPAREN, "')'")) {
return nullptr;
}
std::unique_ptr<Statement> statement = this->statement();
if (!statement) {
return nullptr;
}
Position pos = this->rangeFrom(start);
return this->statementOrNop(pos, ForStatement::ConvertWhile(fCompiler.context(), pos,
std::move(test),
std::move(statement)));
}
/* COLON statement* */
bool Parser::switchCaseBody(ExpressionArray* values,
StatementArray* caseBlocks,
std::unique_ptr<Expression> caseValue) {
if (!this->expect(Token::Kind::TK_COLON, "':'")) {
return false;
}
StatementArray statements;
while (this->peek().fKind != Token::Kind::TK_RBRACE &&
this->peek().fKind != Token::Kind::TK_CASE &&
this->peek().fKind != Token::Kind::TK_DEFAULT) {
std::unique_ptr<Statement> s = this->statement();
if (!s) {
return false;
}
statements.push_back(std::move(s));
}
values->push_back(std::move(caseValue));
caseBlocks->push_back(SkSL::Block::Make(Position(), std::move(statements),
Block::Kind::kUnbracedBlock));
return true;
}
/* CASE expression COLON statement* */
bool Parser::switchCase(ExpressionArray* values, StatementArray* caseBlocks) {
Token start;
if (!this->expect(Token::Kind::TK_CASE, "'case'", &start)) {
return false;
}
std::unique_ptr<Expression> caseValue = this->expression();
if (!caseValue) {
return false;
}
return this->switchCaseBody(values, caseBlocks, std::move(caseValue));
}
/* SWITCH LPAREN expression RPAREN LBRACE switchCase* (DEFAULT COLON statement*)? RBRACE */
std::unique_ptr<Statement> Parser::switchStatement() {
Token start;
if (!this->expect(Token::Kind::TK_SWITCH, "'switch'", &start)) {
return nullptr;
}
if (!this->expect(Token::Kind::TK_LPAREN, "'('")) {
return nullptr;
}
std::unique_ptr<Expression> value = this->expression();
if (!value) {
return nullptr;
}
if (!this->expect(Token::Kind::TK_RPAREN, "')'")) {
return nullptr;
}
if (!this->expect(Token::Kind::TK_LBRACE, "'{'")) {
return nullptr;
}
std::unique_ptr<SymbolTable> symbolTable;
ExpressionArray values;
StatementArray caseBlocks;
{
// Keeping a tight scope around AutoSymbolTable is important here. SwitchStatement::Convert
// may end up creating a new symbol table if the HoistSwitchVarDeclarationsAtTopLevel
// transform is used. We want ~AutoSymbolTable to happen first, so it can restore the
// context's active symbol table to the enclosing block instead of the switch's inner block.
AutoSymbolTable symbols(this, &symbolTable);
while (this->peek().fKind == Token::Kind::TK_CASE) {
if (!this->switchCase(&values, &caseBlocks)) {
return nullptr;
}
}
// Requiring `default:` to be last (in defiance of C and GLSL) was a deliberate decision.
// Other parts of the compiler are allowed to rely upon this assumption.
if (this->checkNext(Token::Kind::TK_DEFAULT)) {
if (!this->switchCaseBody(&values, &caseBlocks, /*value=*/nullptr)) {
return nullptr;
}
}
if (!this->expect(Token::Kind::TK_RBRACE, "'}'")) {
return nullptr;
}
}
Position pos = this->rangeFrom(start);
return this->statementOrNop(pos, SwitchStatement::Convert(fCompiler.context(), pos,
std::move(value),
std::move(values),
std::move(caseBlocks),
std::move(symbolTable)));
}
static Position range_of_at_least_one_char(int start, int end) {
return Position::Range(start, std::max(end, start + 1));
}
/* FOR LPAREN (declaration | expression)? SEMICOLON expression? SEMICOLON expression? RPAREN
STATEMENT */
std::unique_ptr<Statement> Parser::forStatement() {
Token start;
if (!this->expect(Token::Kind::TK_FOR, "'for'", &start)) {
return nullptr;
}
Token lparen;
if (!this->expect(Token::Kind::TK_LPAREN, "'('", &lparen)) {
return nullptr;
}
std::unique_ptr<SymbolTable> symbolTable;
std::unique_ptr<Statement> initializer;
std::unique_ptr<Expression> test;
std::unique_ptr<Expression> next;
std::unique_ptr<Statement> statement;
int firstSemicolonOffset;
Token secondSemicolon;
Token rparen;
{
AutoSymbolTable symbols(this, &symbolTable);
Token nextToken = this->peek();
if (nextToken.fKind == Token::Kind::TK_SEMICOLON) {
// An empty init-statement.
firstSemicolonOffset = this->nextToken().fOffset;
} else {
// The init-statement must be an expression or variable declaration.
initializer = this->varDeclarationsOrExpressionStatement();
if (!initializer) {
return nullptr;
}
firstSemicolonOffset = fLexer.getCheckpoint().fOffset - 1;
}
if (this->peek().fKind != Token::Kind::TK_SEMICOLON) {
test = this->expression();
if (!test) {
return nullptr;
}
}
if (!this->expect(Token::Kind::TK_SEMICOLON, "';'", &secondSemicolon)) {
return nullptr;
}
if (this->peek().fKind != Token::Kind::TK_RPAREN) {
next = this->expression();
if (!next) {
return nullptr;
}
}
if (!this->expect(Token::Kind::TK_RPAREN, "')'", &rparen)) {
return nullptr;
}
statement = this->statement(/*bracesIntroduceNewScope=*/false);
if (!statement) {
return nullptr;
}
}
Position pos = this->rangeFrom(start);
ForLoopPositions loopPositions{
range_of_at_least_one_char(lparen.fOffset + 1, firstSemicolonOffset),
range_of_at_least_one_char(firstSemicolonOffset + 1, secondSemicolon.fOffset),
range_of_at_least_one_char(secondSemicolon.fOffset + 1, rparen.fOffset),
};
return this->statementOrNop(pos, ForStatement::Convert(fCompiler.context(), pos, loopPositions,
std::move(initializer),
std::move(test),
std::move(next),
std::move(statement),
std::move(symbolTable)));
}
/* RETURN expression? SEMICOLON */
std::unique_ptr<Statement> Parser::returnStatement() {
Token start;
if (!this->expect(Token::Kind::TK_RETURN, "'return'", &start)) {
return nullptr;
}
std::unique_ptr<Expression> expression;
if (this->peek().fKind != Token::Kind::TK_SEMICOLON) {
expression = this->expression();
if (!expression) {
return nullptr;
}
}
if (!this->expect(Token::Kind::TK_SEMICOLON, "';'")) {
return nullptr;
}
// We do not check for errors, or coerce the value to the correct type, until the return
// statement is actually added to a function. (This is done in FunctionDefinition::Convert.)
return ReturnStatement::Make(this->rangeFrom(start), std::move(expression));
}
/* BREAK SEMICOLON */
std::unique_ptr<Statement> Parser::breakStatement() {
Token start;
if (!this->expect(Token::Kind::TK_BREAK, "'break'", &start)) {
return nullptr;
}
if (!this->expect(Token::Kind::TK_SEMICOLON, "';'")) {
return nullptr;
}
return SkSL::BreakStatement::Make(this->position(start));
}
/* CONTINUE SEMICOLON */
std::unique_ptr<Statement> Parser::continueStatement() {
Token start;
if (!this->expect(Token::Kind::TK_CONTINUE, "'continue'", &start)) {
return nullptr;
}
if (!this->expect(Token::Kind::TK_SEMICOLON, "';'")) {
return nullptr;
}
return SkSL::ContinueStatement::Make(this->position(start));
}
/* DISCARD SEMICOLON */
std::unique_ptr<Statement> Parser::discardStatement() {
Token start;
if (!this->expect(Token::Kind::TK_DISCARD, "'continue'", &start)) {
return nullptr;
}
if (!this->expect(Token::Kind::TK_SEMICOLON, "';'")) {
return nullptr;
}
Position pos = this->position(start);
return this->statementOrNop(pos, SkSL::DiscardStatement::Convert(fCompiler.context(), pos));
}
/* LBRACE statement* RBRACE */
std::unique_ptr<Statement> Parser::block(bool introduceNewScope,
std::unique_ptr<SymbolTable>* adoptExistingSymbolTable) {
// We can't introduce a new scope _and_ adopt an existing symbol table.
SkASSERT(!(introduceNewScope && adoptExistingSymbolTable));
AutoDepth depth(this);
Token start;
if (!this->expect(Token::Kind::TK_LBRACE, "'{'", &start)) {
return nullptr;
}
if (!depth.increase()) {
return nullptr;
}
std::unique_ptr<SymbolTable> newSymbolTable;
std::unique_ptr<SymbolTable>* symbolTableToUse =
adoptExistingSymbolTable ? adoptExistingSymbolTable : &newSymbolTable;
StatementArray statements;
{
AutoSymbolTable symbols(this, symbolTableToUse, /*enable=*/introduceNewScope);
// Consume statements until we reach the closing brace.
for (;;) {
Token::Kind tokenKind = this->peek().fKind;
if (tokenKind == Token::Kind::TK_RBRACE) {
this->nextToken();
break;
}
if (tokenKind == Token::Kind::TK_END_OF_FILE) {
this->error(this->peek(), "expected '}', but found end of file");
return nullptr;
}
if (std::unique_ptr<Statement> statement = this->statement()) {
statements.push_back(std::move(statement));
}
if (fEncounteredFatalError) {
return nullptr;
}
}
}
return SkSL::Block::MakeBlock(this->rangeFrom(start),
std::move(statements),
Block::Kind::kBracedScope,
std::move(*symbolTableToUse));
}
/* expression SEMICOLON */
std::unique_ptr<Statement> Parser::expressionStatement() {
std::unique_ptr<Expression> expr = this->expression();
if (!expr) {
return nullptr;
}
if (!this->expect(Token::Kind::TK_SEMICOLON, "';'")) {
return nullptr;
}
Position pos = expr->position();
return this->statementOrNop(pos, SkSL::ExpressionStatement::Convert(fCompiler.context(),
std::move(expr)));
}
std::unique_ptr<Expression> Parser::poison(Position pos) {
return Poison::Make(pos, fCompiler.context());
}
std::unique_ptr<Expression> Parser::expressionOrPoison(Position pos,
std::unique_ptr<Expression> expr) {
if (!expr) {
// If no expression was passed in, create a poison expression.
expr = this->poison(pos);
}
// If a valid position was passed in, it must match the expression's position.
SkASSERTF(!pos.valid() || expr->position() == pos,
"expected expression position (%d-%d), but received (%d-%d)",
pos.startOffset(),
pos.endOffset(),
expr->position().startOffset(),
expr->position().endOffset());
return expr;
}
bool Parser::operatorRight(Parser::AutoDepth& depth,
Operator::Kind op,
BinaryParseFn rightFn,
std::unique_ptr<Expression>& expr) {
this->nextToken();
if (!depth.increase()) {
return false;
}
std::unique_ptr<Expression> right = (this->*rightFn)();
if (!right) {
return false;
}
Position pos = expr->position().rangeThrough(right->position());
expr = this->expressionOrPoison(pos, BinaryExpression::Convert(fCompiler.context(), pos,
std::move(expr), op,
std::move(right)));
return true;
}
/* assignmentExpression (COMMA assignmentExpression)* */
std::unique_ptr<Expression> Parser::expression() {
AutoDepth depth(this);
[[maybe_unused]] Token start = this->peek();
std::unique_ptr<Expression> result = this->assignmentExpression();
if (!result) {
return nullptr;
}
while (this->peek().fKind == Token::Kind::TK_COMMA) {
if (!this->operatorRight(depth, Operator::Kind::COMMA, &Parser::assignmentExpression,
result)) {
return nullptr;
}
}
SkASSERTF(result->position().valid(), "Expression %s has invalid position",
result->description().c_str());
SkASSERTF(result->position().startOffset() == this->position(start).startOffset(),
"Expected %s to start at %d (first token: '%.*s'), but it has range %d-%d\n",
result->description().c_str(), this->position(start).startOffset(),
(int)this->text(start).length(), this->text(start).data(),
result->position().startOffset(), result->position().endOffset());
return result;
}
/* ternaryExpression ((EQEQ | STAREQ | SLASHEQ | PERCENTEQ | PLUSEQ | MINUSEQ | SHLEQ | SHREQ |
BITWISEANDEQ | BITWISEXOREQ | BITWISEOREQ | LOGICALANDEQ | LOGICALXOREQ | LOGICALOREQ)
assignmentExpression)*
*/
std::unique_ptr<Expression> Parser::assignmentExpression() {
AutoDepth depth(this);
std::unique_ptr<Expression> result = this->ternaryExpression();
if (!result) {
return nullptr;
}
for (;;) {
Operator::Kind op;
switch (this->peek().fKind) {
case Token::Kind::TK_EQ: op = Operator::Kind::EQ; break;
case Token::Kind::TK_STAREQ: op = Operator::Kind::STAREQ; break;
case Token::Kind::TK_SLASHEQ: op = Operator::Kind::SLASHEQ; break;
case Token::Kind::TK_PERCENTEQ: op = Operator::Kind::PERCENTEQ; break;
case Token::Kind::TK_PLUSEQ: op = Operator::Kind::PLUSEQ; break;
case Token::Kind::TK_MINUSEQ: op = Operator::Kind::MINUSEQ; break;
case Token::Kind::TK_SHLEQ: op = Operator::Kind::SHLEQ; break;
case Token::Kind::TK_SHREQ: op = Operator::Kind::SHREQ; break;
case Token::Kind::TK_BITWISEANDEQ: op = Operator::Kind::BITWISEANDEQ; break;
case Token::Kind::TK_BITWISEXOREQ: op = Operator::Kind::BITWISEXOREQ; break;
case Token::Kind::TK_BITWISEOREQ: op = Operator::Kind::BITWISEOREQ; break;
default: return result;
}
if (!this->operatorRight(depth, op, &Parser::assignmentExpression, result)) {
return nullptr;
}
}
}
/* logicalOrExpression ('?' expression ':' assignmentExpression)? */
std::unique_ptr<Expression> Parser::ternaryExpression() {
AutoDepth depth(this);
std::unique_ptr<Expression> base = this->logicalOrExpression();
if (!base) {
return nullptr;
}
if (!this->checkNext(Token::Kind::TK_QUESTION)) {
return base;
}
if (!depth.increase()) {
return nullptr;
}
std::unique_ptr<Expression> trueExpr = this->expression();
if (!trueExpr) {
return nullptr;
}
if (!this->expect(Token::Kind::TK_COLON, "':'")) {
return nullptr;
}
std::unique_ptr<Expression> falseExpr = this->assignmentExpression();
if (!falseExpr) {
return nullptr;
}
Position pos = base->position().rangeThrough(falseExpr->position());
return this->expressionOrPoison(pos, TernaryExpression::Convert(fCompiler.context(),
pos, std::move(base),
std::move(trueExpr),
std::move(falseExpr)));
}
/* logicalXorExpression (LOGICALOR logicalXorExpression)* */
std::unique_ptr<Expression> Parser::logicalOrExpression() {
AutoDepth depth(this);
std::unique_ptr<Expression> result = this->logicalXorExpression();
if (!result) {
return nullptr;
}
while (this->peek().fKind == Token::Kind::TK_LOGICALOR) {
if (!this->operatorRight(depth, Operator::Kind::LOGICALOR, &Parser::logicalXorExpression,
result)) {
return nullptr;
}
}
return result;
}
/* logicalAndExpression (LOGICALXOR logicalAndExpression)* */
std::unique_ptr<Expression> Parser::logicalXorExpression() {
AutoDepth depth(this);
std::unique_ptr<Expression> result = this->logicalAndExpression();
if (!result) {
return nullptr;
}
while (this->peek().fKind == Token::Kind::TK_LOGICALXOR) {
if (!this->operatorRight(depth, Operator::Kind::LOGICALXOR, &Parser::logicalAndExpression,
result)) {
return nullptr;
}
}
return result;
}
/* bitwiseOrExpression (LOGICALAND bitwiseOrExpression)* */
std::unique_ptr<Expression> Parser::logicalAndExpression() {
AutoDepth depth(this);
std::unique_ptr<Expression> result = this->bitwiseOrExpression();
if (!result) {
return nullptr;
}
while (this->peek().fKind == Token::Kind::TK_LOGICALAND) {
if (!this->operatorRight(depth, Operator::Kind::LOGICALAND, &Parser::bitwiseOrExpression,
result)) {
return nullptr;
}
}
return result;
}
/* bitwiseXorExpression (BITWISEOR bitwiseXorExpression)* */
std::unique_ptr<Expression> Parser::bitwiseOrExpression() {
AutoDepth depth(this);
std::unique_ptr<Expression> result = this->bitwiseXorExpression();
if (!result) {
return nullptr;
}
while (this->peek().fKind == Token::Kind::TK_BITWISEOR) {
if (!this->operatorRight(depth, Operator::Kind::BITWISEOR, &Parser::bitwiseXorExpression,
result)) {
return nullptr;
}
}
return result;
}
/* bitwiseAndExpression (BITWISEXOR bitwiseAndExpression)* */
std::unique_ptr<Expression> Parser::bitwiseXorExpression() {
AutoDepth depth(this);
std::unique_ptr<Expression> result = this->bitwiseAndExpression();
if (!result) {
return nullptr;
}
while (this->peek().fKind == Token::Kind::TK_BITWISEXOR) {
if (!this->operatorRight(depth, Operator::Kind::BITWISEXOR, &Parser::bitwiseAndExpression,
result)) {
return nullptr;
}
}
return result;
}
/* equalityExpression (BITWISEAND equalityExpression)* */
std::unique_ptr<Expression> Parser::bitwiseAndExpression() {
AutoDepth depth(this);
std::unique_ptr<Expression> result = this->equalityExpression();
if (!result) {
return nullptr;
}
while (this->peek().fKind == Token::Kind::TK_BITWISEAND) {
if (!this->operatorRight(depth, Operator::Kind::BITWISEAND, &Parser::equalityExpression,
result)) {
return nullptr;
}
}
return result;
}
/* relationalExpression ((EQEQ | NEQ) relationalExpression)* */
std::unique_ptr<Expression> Parser::equalityExpression() {
AutoDepth depth(this);
std::unique_ptr<Expression> result = this->relationalExpression();
if (!result) {
return nullptr;
}
for (;;) {
Operator::Kind op;
switch (this->peek().fKind) {
case Token::Kind::TK_EQEQ: op = Operator::Kind::EQEQ; break;
case Token::Kind::TK_NEQ: op = Operator::Kind::NEQ; break;
default: return result;
}
if (!this->operatorRight(depth, op, &Parser::relationalExpression, result)) {
return nullptr;
}
}
}
/* shiftExpression ((LT | GT | LTEQ | GTEQ) shiftExpression)* */
std::unique_ptr<Expression> Parser::relationalExpression() {
AutoDepth depth(this);
std::unique_ptr<Expression> result = this->shiftExpression();
if (!result) {
return nullptr;
}
for (;;) {
Operator::Kind op;
switch (this->peek().fKind) {
case Token::Kind::TK_LT: op = Operator::Kind::LT; break;
case Token::Kind::TK_GT: op = Operator::Kind::GT; break;
case Token::Kind::TK_LTEQ: op = Operator::Kind::LTEQ; break;
case Token::Kind::TK_GTEQ: op = Operator::Kind::GTEQ; break;
default: return result;
}
if (!this->operatorRight(depth, op, &Parser::shiftExpression, result)) {
return nullptr;
}
}
}
/* additiveExpression ((SHL | SHR) additiveExpression)* */
std::unique_ptr<Expression> Parser::shiftExpression() {
AutoDepth depth(this);
std::unique_ptr<Expression> result = this->additiveExpression();
if (!result) {
return nullptr;
}
for (;;) {
Operator::Kind op;
switch (this->peek().fKind) {
case Token::Kind::TK_SHL: op = Operator::Kind::SHL; break;
case Token::Kind::TK_SHR: op = Operator::Kind::SHR; break;
default: return result;
}
if (!this->operatorRight(depth, op, &Parser::additiveExpression, result)) {
return nullptr;
}
}
}
/* multiplicativeExpression ((PLUS | MINUS) multiplicativeExpression)* */
std::unique_ptr<Expression> Parser::additiveExpression() {
AutoDepth depth(this);
std::unique_ptr<Expression> result = this->multiplicativeExpression();
if (!result) {
return nullptr;
}
for (;;) {
Operator::Kind op;
switch (this->peek().fKind) {
case Token::Kind::TK_PLUS: op = Operator::Kind::PLUS; break;
case Token::Kind::TK_MINUS: op = Operator::Kind::MINUS; break;
default: return result;
}
if (!this->operatorRight(depth, op, &Parser::multiplicativeExpression, result)) {
return nullptr;
}
}
}
/* unaryExpression ((STAR | SLASH | PERCENT) unaryExpression)* */
std::unique_ptr<Expression> Parser::multiplicativeExpression() {
AutoDepth depth(this);
std::unique_ptr<Expression> result = this->unaryExpression();
if (!result) {
return nullptr;
}
for (;;) {
Operator::Kind op;
switch (this->peek().fKind) {
case Token::Kind::TK_STAR: op = Operator::Kind::STAR; break;
case Token::Kind::TK_SLASH: op = Operator::Kind::SLASH; break;
case Token::Kind::TK_PERCENT: op = Operator::Kind::PERCENT; break;
default: return result;
}
if (!this->operatorRight(depth, op, &Parser::unaryExpression, result)) {
return nullptr;
}
}
}
/* postfixExpression | (PLUS | MINUS | NOT | PLUSPLUS | MINUSMINUS) unaryExpression */
std::unique_ptr<Expression> Parser::unaryExpression() {
AutoDepth depth(this);
Operator::Kind op;
Token start = this->peek();
switch (start.fKind) {
case Token::Kind::TK_PLUS: op = Operator::Kind::PLUS; break;
case Token::Kind::TK_MINUS: op = Operator::Kind::MINUS; break;
case Token::Kind::TK_LOGICALNOT: op = Operator::Kind::LOGICALNOT; break;
case Token::Kind::TK_BITWISENOT: op = Operator::Kind::BITWISENOT; break;
case Token::Kind::TK_PLUSPLUS: op = Operator::Kind::PLUSPLUS; break;
case Token::Kind::TK_MINUSMINUS: op = Operator::Kind::MINUSMINUS; break;
default: return this->postfixExpression();
}
this->nextToken();
if (!depth.increase()) {
return nullptr;
}
std::unique_ptr<Expression> expr = this->unaryExpression();
if (!expr) {
return nullptr;
}
Position pos = Position::Range(start.fOffset, expr->position().endOffset());
return this->expressionOrPoison(pos, PrefixExpression::Convert(fCompiler.context(),
pos, op, std::move(expr)));
}
/* term suffix* */
std::unique_ptr<Expression> Parser::postfixExpression() {
AutoDepth depth(this);
std::unique_ptr<Expression> result = this->term();
if (!result) {
return nullptr;
}
for (;;) {
Token t = this->peek();
switch (t.fKind) {
case Token::Kind::TK_FLOAT_LITERAL:
if (this->text(t)[0] != '.') {
return result;
}
[[fallthrough]];
case Token::Kind::TK_LBRACKET:
case Token::Kind::TK_DOT:
case Token::Kind::TK_LPAREN:
case Token::Kind::TK_PLUSPLUS:
case Token::Kind::TK_MINUSMINUS: {
if (!depth.increase()) {
return nullptr;
}
result = this->suffix(std::move(result));
if (!result) {
return nullptr;
}
break;
}
default:
return result;
}
}
}
std::unique_ptr<Expression> Parser::swizzle(Position pos,
std::unique_ptr<Expression> base,
std::string_view swizzleMask,
Position maskPos) {
SkASSERT(!swizzleMask.empty());
if (!base->type().isVector() && !base->type().isScalar()) {
return this->expressionOrPoison(pos, FieldAccess::Convert(fCompiler.context(), pos,
std::move(base), swizzleMask));
}
return this->expressionOrPoison(pos, Swizzle::Convert(fCompiler.context(), pos, maskPos,
std::move(base), swizzleMask));
}
std::unique_ptr<Expression> Parser::call(Position pos,
std::unique_ptr<Expression> base,
ExpressionArray args) {
return this->expressionOrPoison(pos, SkSL::FunctionCall::Convert(fCompiler.context(), pos,
std::move(base),
std::move(args)));
}
/* LBRACKET expression? RBRACKET | DOT IDENTIFIER | LPAREN arguments RPAREN |
PLUSPLUS | MINUSMINUS | COLONCOLON IDENTIFIER | FLOAT_LITERAL [IDENTIFIER] */
std::unique_ptr<Expression> Parser::suffix(std::unique_ptr<Expression> base) {
AutoDepth depth(this);
Token next = this->nextToken();
if (!depth.increase()) {
return nullptr;
}
switch (next.fKind) {
case Token::Kind::TK_LBRACKET: {
if (this->checkNext(Token::Kind::TK_RBRACKET)) {
this->error(this->rangeFrom(next), "missing index in '[]'");
return this->poison(this->rangeFrom(base->position()));
}
std::unique_ptr<Expression> index = this->expression();
if (!index) {
return nullptr;
}
this->expect(Token::Kind::TK_RBRACKET, "']' to complete array access expression");
Position pos = this->rangeFrom(base->position());
return this->expressionOrPoison(pos, IndexExpression::Convert(fCompiler.context(), pos,
std::move(base),
std::move(index)));
}
case Token::Kind::TK_DOT: {
std::string_view text;
if (this->identifier(&text)) {
Position pos = this->rangeFrom(base->position());
return this->swizzle(pos, std::move(base), text,
this->rangeFrom(this->position(next).after()));
}
[[fallthrough]];
}
case Token::Kind::TK_FLOAT_LITERAL: {
// Swizzles that start with a constant number, e.g. '.000r', will be tokenized as
// floating point literals, possibly followed by an identifier. Handle that here.
std::string_view field = this->text(next);
SkASSERT(field[0] == '.');
field.remove_prefix(1);
// use the next *raw* token so we don't ignore whitespace - we only care about
// identifiers that directly follow the float
Position pos = this->rangeFrom(base->position());
Position start = this->position(next);
// skip past the "."
start = Position::Range(start.startOffset() + 1, start.endOffset());
Position maskPos = this->rangeFrom(start);
Token id = this->nextRawToken();
if (id.fKind == Token::Kind::TK_IDENTIFIER) {
pos = this->rangeFrom(base->position());
maskPos = this->rangeFrom(start);
return this->swizzle(pos,
std::move(base),
std::string(field) + std::string(this->text(id)),
maskPos);
}
if (field.empty()) {
this->error(pos, "expected field name or swizzle mask after '.'");
return this->poison(pos);
}
this->pushback(id);
return this->swizzle(pos, std::move(base), field, maskPos);
}
case Token::Kind::TK_LPAREN: {
ExpressionArray args;
if (this->peek().fKind != Token::Kind::TK_RPAREN) {
for (;;) {
std::unique_ptr<Expression> expr = this->assignmentExpression();
if (!expr) {
return nullptr;
}
args.push_back(std::move(expr));
if (!this->checkNext(Token::Kind::TK_COMMA)) {
break;
}
}
}
this->expect(Token::Kind::TK_RPAREN, "')' to complete function arguments");
Position pos = this->rangeFrom(base->position());
return this->call(pos, std::move(base), std::move(args));
}
case Token::Kind::TK_PLUSPLUS:
case Token::Kind::TK_MINUSMINUS: {
Operator::Kind op = (next.fKind == Token::Kind::TK_PLUSPLUS)
? Operator::Kind::PLUSPLUS
: Operator::Kind::MINUSMINUS;
Position pos = this->rangeFrom(base->position());
return this->expressionOrPoison(pos, PostfixExpression::Convert(fCompiler.context(),
pos, std::move(base),
op));
}
default: {
this->error(next, "expected expression suffix, but found '" +
std::string(this->text(next)) + "'");
return nullptr;
}
}
}
/* IDENTIFIER | intLiteral | floatLiteral | boolLiteral | '(' expression ')' */
std::unique_ptr<Expression> Parser::term() {
AutoDepth depth(this);
Token t = this->peek();
switch (t.fKind) {
case Token::Kind::TK_IDENTIFIER: {
std::string_view text;
if (this->identifier(&text)) {
Position pos = this->position(t);
return this->expressionOrPoison(
pos,
this->symbolTable()->instantiateSymbolRef(fCompiler.context(), text, pos));
}
break;
}
case Token::Kind::TK_INT_LITERAL: {
SKSL_INT i;
if (!this->intLiteral(&i)) {
i = 0;
}
Position pos = this->position(t);
return this->expressionOrPoison(pos, SkSL::Literal::MakeInt(fCompiler.context(),
pos, i));
}
case Token::Kind::TK_FLOAT_LITERAL: {
SKSL_FLOAT f;
if (!this->floatLiteral(&f)) {
f = 0.0f;
}
Position pos = this->position(t);
return this->expressionOrPoison(pos, SkSL::Literal::MakeFloat(fCompiler.context(),
pos, f));
}
case Token::Kind::TK_TRUE_LITERAL: // fall through
case Token::Kind::TK_FALSE_LITERAL: {
bool b;
SkAssertResult(this->boolLiteral(&b));
Position pos = this->position(t);
return this->expressionOrPoison(pos, SkSL::Literal::MakeBool(fCompiler.context(),
pos, b));
}
case Token::Kind::TK_LPAREN: {
this->nextToken();
if (!depth.increase()) {
return nullptr;
}
std::unique_ptr<Expression> result = this->expression();
if (result != nullptr) {
this->expect(Token::Kind::TK_RPAREN, "')' to complete expression");
result->setPosition(this->rangeFrom(this->position(t)));
return result;
}
break;
}
default:
this->nextToken();
this->error(t, "expected expression, but found '" + std::string(this->text(t)) + "'");
fEncounteredFatalError = true;
break;
}
return nullptr;
}
/* INT_LITERAL */
bool Parser::intLiteral(SKSL_INT* dest) {
Token t;
if (!this->expect(Token::Kind::TK_INT_LITERAL, "integer literal", &t)) {
return false;
}
std::string_view s = this->text(t);
if (!SkSL::stoi(s, dest)) {
this->error(t, "integer is too large: " + std::string(s));
return false;
}
return true;
}
/* FLOAT_LITERAL */
bool Parser::floatLiteral(SKSL_FLOAT* dest) {
Token t;
if (!this->expect(Token::Kind::TK_FLOAT_LITERAL, "float literal", &t)) {
return false;
}
std::string_view s = this->text(t);
if (!SkSL::stod(s, dest)) {
this->error(t, "floating-point value is too large: " + std::string(s));
return false;
}
return true;
}
/* TRUE_LITERAL | FALSE_LITERAL */
bool Parser::boolLiteral(bool* dest) {
Token t = this->nextToken();
switch (t.fKind) {
case Token::Kind::TK_TRUE_LITERAL:
*dest = true;
return true;
case Token::Kind::TK_FALSE_LITERAL:
*dest = false;
return true;
default:
this->error(t, "expected 'true' or 'false', but found '" +
std::string(this->text(t)) + "'");
return false;
}
}
/* IDENTIFIER */
bool Parser::identifier(std::string_view* dest) {
Token t;
if (this->expect(Token::Kind::TK_IDENTIFIER, "identifier", &t)) {
*dest = this->text(t);
return true;
}
return false;
}
} // namespace SkSL