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dawn / tint / 95d40776483507379e3c70272d87a4a09baea444 / . / src / reader / wgsl / parser_impl.cc
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// Copyright 2020 The Tint Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "src/reader/wgsl/parser_impl.h"
#include "src/ast/access_decoration.h"
#include "src/ast/bitcast_expression.h"
#include "src/ast/constant_id_decoration.h"
#include "src/ast/discard_statement.h"
#include "src/ast/fallthrough_statement.h"
#include "src/ast/stage_decoration.h"
#include "src/ast/struct_block_decoration.h"
#include "src/ast/unary_op_expression.h"
#include "src/ast/workgroup_decoration.h"
#include "src/reader/wgsl/lexer.h"
#include "src/type/access_control_type.h"
#include "src/type/depth_texture_type.h"
#include "src/type/multisampled_texture_type.h"
#include "src/type/sampled_texture_type.h"
namespace tint {
namespace reader {
namespace wgsl {
namespace {
template <typename T>
using Expect = ParserImpl::Expect<T>;
template <typename T>
using Maybe = ParserImpl::Maybe<T>;
/// Controls the maximum number of times we'll call into the sync() function
/// from itself. This is to guard against stack overflow when there is an
/// excessive number of blocks.
constexpr uint32_t kMaxSyncDepth = 128;
/// The maximum number of tokens to look ahead to try and sync the
/// parser on error.
constexpr size_t const kMaxResynchronizeLookahead = 32;
const char kVertexStage[] = "vertex";
const char kFragmentStage[] = "fragment";
const char kComputeStage[] = "compute";
const char kReadAccessControl[] = "read";
const char kWriteAccessControl[] = "write";
const char kReadWriteAccessControl[] = "read_write";
ast::Builtin ident_to_builtin(const std::string& str) {
if (str == "position") {
return ast::Builtin::kPosition;
}
if (str == "vertex_idx" || str == "vertex_index") {
return ast::Builtin::kVertexIndex;
}
if (str == "instance_idx" || str == "instance_index") {
return ast::Builtin::kInstanceIndex;
}
if (str == "front_facing") {
return ast::Builtin::kFrontFacing;
}
if (str == "frag_coord") {
return ast::Builtin::kFragCoord;
}
if (str == "frag_depth") {
return ast::Builtin::kFragDepth;
}
if (str == "local_invocation_id") {
return ast::Builtin::kLocalInvocationId;
}
if (str == "local_invocation_idx" || str == "local_invocation_index") {
return ast::Builtin::kLocalInvocationIndex;
}
if (str == "global_invocation_id") {
return ast::Builtin::kGlobalInvocationId;
}
if (str == "sample_index") {
return ast::Builtin::kSampleIndex;
}
if (str == "sample_mask_in") {
return ast::Builtin::kSampleMaskIn;
}
if (str == "sample_mask_out") {
return ast::Builtin::kSampleMaskOut;
}
return ast::Builtin::kNone;
}
const char kAccessDecoration[] = "access";
const char kBindingDecoration[] = "binding";
const char kBlockDecoration[] = "block";
const char kBuiltinDecoration[] = "builtin";
const char kConstantIdDecoration[] = "constant_id";
const char kGroupDecoration[] = "group";
const char kLocationDecoration[] = "location";
const char kOffsetDecoration[] = "offset";
const char kSetDecoration[] = "set";
const char kStageDecoration[] = "stage";
const char kStrideDecoration[] = "stride";
const char kWorkgroupSizeDecoration[] = "workgroup_size";
bool is_decoration(Token t) {
if (!t.IsIdentifier())
return false;
auto s = t.to_str();
return s == kAccessDecoration || s == kBindingDecoration ||
s == kBlockDecoration || s == kBuiltinDecoration ||
s == kConstantIdDecoration || s == kLocationDecoration ||
s == kOffsetDecoration || s == kSetDecoration ||
s == kGroupDecoration || s == kStageDecoration ||
s == kStrideDecoration || s == kWorkgroupSizeDecoration;
}
/// Enter-exit counters for block token types.
/// Used by sync_to() to skip over closing block tokens that were opened during
/// the forward scan.
struct BlockCounters {
int attrs = 0; // [[ ]]
int brace = 0; // { }
int bracket = 0; // [ ]
int paren = 0; // ( )
/// @return the current enter-exit depth for the given block token type. If
/// `t` is not a block token type, then 0 is always returned.
int consume(const Token& t) {
if (t.Is(Token::Type::kAttrLeft))
return attrs++;
if (t.Is(Token::Type::kAttrRight))
return attrs--;
if (t.Is(Token::Type::kBraceLeft))
return brace++;
if (t.Is(Token::Type::kBraceRight))
return brace--;
if (t.Is(Token::Type::kBracketLeft))
return bracket++;
if (t.Is(Token::Type::kBracketRight))
return bracket--;
if (t.Is(Token::Type::kParenLeft))
return paren++;
if (t.Is(Token::Type::kParenRight))
return paren--;
return 0;
}
};
} // namespace
ParserImpl::FunctionHeader::FunctionHeader() = default;
ParserImpl::FunctionHeader::FunctionHeader(const FunctionHeader&) = default;
ParserImpl::FunctionHeader::FunctionHeader(Source src,
std::string n,
ast::VariableList p,
type::Type* ret_ty)
: source(src), name(n), params(p), return_type(ret_ty) {}
ParserImpl::FunctionHeader::~FunctionHeader() = default;
ParserImpl::FunctionHeader& ParserImpl::FunctionHeader::operator=(
const FunctionHeader& rhs) = default;
ParserImpl::ParserImpl(Source::File const* file)
: lexer_(std::make_unique<Lexer>(file->path, &file->content)) {}
ParserImpl::~ParserImpl() = default;
ParserImpl::Failure::Errored ParserImpl::add_error(const Source& source,
const std::string& err,
const std::string& use) {
std::stringstream msg;
msg << err;
if (!use.empty()) {
msg << " for " << use;
}
add_error(source, msg.str());
return Failure::kErrored;
}
ParserImpl::Failure::Errored ParserImpl::add_error(const Token& t,
const std::string& err) {
add_error(t.source(), err);
return Failure::kErrored;
}
ParserImpl::Failure::Errored ParserImpl::add_error(const Source& source,
const std::string& err) {
if (silence_errors_ == 0) {
builder_.Diagnostics().add_error(err, source);
}
return Failure::kErrored;
}
Token ParserImpl::next() {
if (!token_queue_.empty()) {
auto t = token_queue_.front();
token_queue_.pop_front();
return t;
}
return lexer_->next();
}
Token ParserImpl::peek(size_t idx) {
while (token_queue_.size() < (idx + 1))
token_queue_.push_back(lexer_->next());
return token_queue_[idx];
}
Token ParserImpl::peek() {
return peek(0);
}
void ParserImpl::register_constructed(const std::string& name,
type::Type* type) {
assert(type);
registered_constructs_[name] = type;
}
type::Type* ParserImpl::get_constructed(const std::string& name) {
if (registered_constructs_.find(name) == registered_constructs_.end()) {
return nullptr;
}
return registered_constructs_[name];
}
bool ParserImpl::Parse() {
translation_unit();
return !has_error();
}
// translation_unit
// : global_decl* EOF
void ParserImpl::translation_unit() {
while (synchronized_) {
auto p = peek();
if (p.IsEof()) {
break;
}
expect_global_decl();
if (builder_.Diagnostics().error_count() >= max_errors_) {
add_error(Source{{}, p.source().file_path},
"stopping after " + std::to_string(max_errors_) + " errors");
break;
}
}
}
// global_decl
// : SEMICOLON
// | global_variable_decl SEMICLON
// | global_constant_decl SEMICOLON
// | type_alias SEMICOLON
// | struct_decl SEMICOLON
// | function_decl
Expect<bool> ParserImpl::expect_global_decl() {
if (match(Token::Type::kSemicolon) || match(Token::Type::kEOF))
return true;
bool errored = false;
auto decos = decoration_list();
if (decos.errored)
errored = true;
if (!synchronized_)
return Failure::kErrored;
auto decl = sync(Token::Type::kSemicolon, [&]() -> Maybe<bool> {
auto gv = global_variable_decl(decos.value);
if (gv.errored)
return Failure::kErrored;
if (gv.matched) {
if (!expect("variable declaration", Token::Type::kSemicolon))
return Failure::kErrored;
builder_.AST().AddGlobalVariable(gv.value);
return true;
}
auto gc = global_constant_decl(decos.value);
if (gc.errored)
return Failure::kErrored;
if (gc.matched) {
if (!expect("constant declaration", Token::Type::kSemicolon))
return Failure::kErrored;
builder_.AST().AddGlobalVariable(gc.value);
return true;
}
auto ta = type_alias();
if (ta.errored)
return Failure::kErrored;
if (ta.matched) {
if (!expect("type alias", Token::Type::kSemicolon))
return Failure::kErrored;
builder_.AST().AddConstructedType(ta.value);
return true;
}
auto str = struct_decl(decos.value);
if (str.errored)
return Failure::kErrored;
if (str.matched) {
if (!expect("struct declaration", Token::Type::kSemicolon))
return Failure::kErrored;
register_constructed(builder_.Symbols().NameFor(str.value->symbol()),
str.value);
builder_.AST().AddConstructedType(str.value);
return true;
}
return Failure::kNoMatch;
});
if (decl.errored)
errored = true;
if (decl.matched)
return true;
auto func = function_decl(decos.value);
if (func.errored)
errored = true;
if (func.matched) {
builder_.AST().AddFunction(func.value);
return true;
}
if (errored)
return Failure::kErrored;
// Invalid syntax found - try and determine the best error message
// We have decorations parsed, but nothing to consume them?
if (decos.value.size() > 0)
return add_error(next(), "expected declaration after decorations");
// We have a statement outside of a function?
auto t = peek();
auto stat = without_error([&] { return statement(); });
if (stat.matched) {
// Attempt to jump to the next '}' - the function might have just been
// missing an opening line.
sync_to(Token::Type::kBraceRight, true);
return add_error(t, "statement found outside of function body");
}
if (!stat.errored) {
// No match, no error - the parser might not have progressed.
// Ensure we always make _some_ forward progress.
next();
}
// Exhausted all attempts to make sense of where we're at.
// Spew a generic error.
return add_error(t, "unexpected token");
}
// global_variable_decl
// : variable_decoration_list* variable_decl
// | variable_decoration_list* variable_decl EQUAL const_expr
Maybe<ast::Variable*> ParserImpl::global_variable_decl(
ast::DecorationList& decos) {
auto decl = variable_decl();
if (decl.errored)
return Failure::kErrored;
if (!decl.matched)
return Failure::kNoMatch;
ast::Expression* constructor = nullptr;
if (match(Token::Type::kEqual)) {
auto expr = expect_const_expr();
if (expr.errored)
return Failure::kErrored;
constructor = expr.value;
}
return create<ast::Variable>(
decl->source, // source
builder_.Symbols().Register(decl->name), // symbol
decl->storage_class, // storage_class
decl->type, // type
false, // is_const
constructor, // constructor
std::move(decos)); // decorations
}
// global_constant_decl
// : variable_decoration_list* CONST variable_ident_decl EQUAL const_expr
Maybe<ast::Variable*> ParserImpl::global_constant_decl(
ast::DecorationList& decos) {
if (!match(Token::Type::kConst))
return Failure::kNoMatch;
const char* use = "constant declaration";
auto decl = expect_variable_ident_decl(use);
if (decl.errored)
return Failure::kErrored;
if (!expect(use, Token::Type::kEqual))
return Failure::kErrored;
auto init = expect_const_expr();
if (init.errored)
return Failure::kErrored;
return create<ast::Variable>(
decl->source, // source
builder_.Symbols().Register(decl->name), // symbol
ast::StorageClass::kNone, // storage_class
decl->type, // type
true, // is_const
init.value, // constructor
std::move(decos)); // decorations
}
// variable_decl
// : VAR variable_storage_decoration? variable_ident_decl
Maybe<ParserImpl::VarDeclInfo> ParserImpl::variable_decl() {
if (!match(Token::Type::kVar))
return Failure::kNoMatch;
ast::StorageClass sc = ast::StorageClass::kNone;
auto explicit_sc = variable_storage_decoration();
if (explicit_sc.errored)
return Failure::kErrored;
if (explicit_sc.matched)
sc = explicit_sc.value;
auto decl = expect_variable_ident_decl("variable declaration");
if (decl.errored)
return Failure::kErrored;
if (decl->type->UnwrapAll()->is_handle()) {
// handle types implicitly have the `UniformConstant` storage class.
// TODO(jrprice): Produce an error if an explicit storage class is provided.
sc = ast::StorageClass::kUniformConstant;
}
return VarDeclInfo{decl->source, decl->name, sc, decl->type};
}
// texture_sampler_types
// : sampler_type
// | depth_texture_type
// | sampled_texture_type LESS_THAN type_decl GREATER_THAN
// | multisampled_texture_type LESS_THAN type_decl GREATER_THAN
// | storage_texture_type LESS_THAN image_storage_type GREATER_THAN
Maybe<type::Type*> ParserImpl::texture_sampler_types() {
auto type = sampler_type();
if (type.matched)
return type;
type = depth_texture_type();
if (type.matched)
return type.value;
auto dim = sampled_texture_type();
if (dim.matched) {
const char* use = "sampled texture type";
auto subtype = expect_lt_gt_block(use, [&] { return expect_type(use); });
if (subtype.errored)
return Failure::kErrored;
return builder_.create<type::SampledTexture>(dim.value, subtype.value);
}
auto ms_dim = multisampled_texture_type();
if (ms_dim.matched) {
const char* use = "multisampled texture type";
auto subtype = expect_lt_gt_block(use, [&] { return expect_type(use); });
if (subtype.errored)
return Failure::kErrored;
return builder_.create<type::MultisampledTexture>(ms_dim.value,
subtype.value);
}
auto storage = storage_texture_type();
if (storage.matched) {
const char* use = "storage texture type";
auto format =
expect_lt_gt_block(use, [&] { return expect_image_storage_type(use); });
if (format.errored)
return Failure::kErrored;
auto* subtype =
type::StorageTexture::SubtypeFor(format.value, builder_.Types());
return builder_.create<type::StorageTexture>(storage.value, format.value,
subtype);
}
return Failure::kNoMatch;
}
// sampler_type
// : SAMPLER
// | SAMPLER_COMPARISON
Maybe<type::Type*> ParserImpl::sampler_type() {
if (match(Token::Type::kSampler))
return builder_.create<type::Sampler>(type::SamplerKind::kSampler);
if (match(Token::Type::kComparisonSampler))
return builder_.create<type::Sampler>(
type::SamplerKind::kComparisonSampler);
return Failure::kNoMatch;
}
// sampled_texture_type
// : TEXTURE_SAMPLED_1D
// | TEXTURE_SAMPLED_2D
// | TEXTURE_SAMPLED_2D_ARRAY
// | TEXTURE_SAMPLED_3D
// | TEXTURE_SAMPLED_CUBE
// | TEXTURE_SAMPLED_CUBE_ARRAY
Maybe<type::TextureDimension> ParserImpl::sampled_texture_type() {
if (match(Token::Type::kTextureSampled1d))
return type::TextureDimension::k1d;
if (match(Token::Type::kTextureSampled2d))
return type::TextureDimension::k2d;
if (match(Token::Type::kTextureSampled2dArray))
return type::TextureDimension::k2dArray;
if (match(Token::Type::kTextureSampled3d))
return type::TextureDimension::k3d;
if (match(Token::Type::kTextureSampledCube))
return type::TextureDimension::kCube;
if (match(Token::Type::kTextureSampledCubeArray))
return type::TextureDimension::kCubeArray;
return Failure::kNoMatch;
}
// multisampled_texture_type
// : TEXTURE_MULTISAMPLED_2D
Maybe<type::TextureDimension> ParserImpl::multisampled_texture_type() {
if (match(Token::Type::kTextureMultisampled2d))
return type::TextureDimension::k2d;
return Failure::kNoMatch;
}
// storage_texture_type
// : TEXTURE_STORAGE_1D
// | TEXTURE_STORAGE_2D
// | TEXTURE_STORAGE_2D_ARRAY
// | TEXTURE_STORAGE_3D
Maybe<type::TextureDimension> ParserImpl::storage_texture_type() {
if (match(Token::Type::kTextureStorage1d))
return type::TextureDimension::k1d;
if (match(Token::Type::kTextureStorage2d))
return type::TextureDimension::k2d;
if (match(Token::Type::kTextureStorage2dArray))
return type::TextureDimension::k2dArray;
if (match(Token::Type::kTextureStorage3d))
return type::TextureDimension::k3d;
return Failure::kNoMatch;
}
// depth_texture_type
// : TEXTURE_DEPTH_2D
// | TEXTURE_DEPTH_2D_ARRAY
// | TEXTURE_DEPTH_CUBE
// | TEXTURE_DEPTH_CUBE_ARRAY
Maybe<type::Type*> ParserImpl::depth_texture_type() {
if (match(Token::Type::kTextureDepth2d))
return builder_.create<type::DepthTexture>(type::TextureDimension::k2d);
if (match(Token::Type::kTextureDepth2dArray))
return builder_.create<type::DepthTexture>(
type::TextureDimension::k2dArray);
if (match(Token::Type::kTextureDepthCube))
return builder_.create<type::DepthTexture>(type::TextureDimension::kCube);
if (match(Token::Type::kTextureDepthCubeArray))
return builder_.create<type::DepthTexture>(
type::TextureDimension::kCubeArray);
return Failure::kNoMatch;
}
// image_storage_type
// : R8UNORM
// | R8SNORM
// | R8UINT
// | R8SINT
// | R16UINT
// | R16SINT
// | R16FLOAT
// | RG8UNORM
// | RG8SNORM
// | RG8UINT
// | RG8SINT
// | R32UINT
// | R32SINT
// | R32FLOAT
// | RG16UINT
// | RG16SINT
// | RG16FLOAT
// | RGBA8UNORM
/// | RGBA8UNORM-SRGB
// | RGBA8SNORM
// | RGBA8UINT
// | RGBA8SINT
// | BGRA8UNORM
// | BGRA8UNORM-SRGB
// | RGB10A2UNORM
// | RG11B10FLOAT
// | RG32UINT
// | RG32SINT
// | RG32FLOAT
// | RGBA16UINT
// | RGBA16SINT
// | RGBA16FLOAT
// | RGBA32UINT
// | RGBA32SINT
// | RGBA32FLOAT
Expect<type::ImageFormat> ParserImpl::expect_image_storage_type(
const std::string& use) {
if (match(Token::Type::kFormatR8Unorm))
return type::ImageFormat::kR8Unorm;
if (match(Token::Type::kFormatR8Snorm))
return type::ImageFormat::kR8Snorm;
if (match(Token::Type::kFormatR8Uint))
return type::ImageFormat::kR8Uint;
if (match(Token::Type::kFormatR8Sint))
return type::ImageFormat::kR8Sint;
if (match(Token::Type::kFormatR16Uint))
return type::ImageFormat::kR16Uint;
if (match(Token::Type::kFormatR16Sint))
return type::ImageFormat::kR16Sint;
if (match(Token::Type::kFormatR16Float))
return type::ImageFormat::kR16Float;
if (match(Token::Type::kFormatRg8Unorm))
return type::ImageFormat::kRg8Unorm;
if (match(Token::Type::kFormatRg8Snorm))
return type::ImageFormat::kRg8Snorm;
if (match(Token::Type::kFormatRg8Uint))
return type::ImageFormat::kRg8Uint;
if (match(Token::Type::kFormatRg8Sint))
return type::ImageFormat::kRg8Sint;
if (match(Token::Type::kFormatR32Uint))
return type::ImageFormat::kR32Uint;
if (match(Token::Type::kFormatR32Sint))
return type::ImageFormat::kR32Sint;
if (match(Token::Type::kFormatR32Float))
return type::ImageFormat::kR32Float;
if (match(Token::Type::kFormatRg16Uint))
return type::ImageFormat::kRg16Uint;
if (match(Token::Type::kFormatRg16Sint))
return type::ImageFormat::kRg16Sint;
if (match(Token::Type::kFormatRg16Float))
return type::ImageFormat::kRg16Float;
if (match(Token::Type::kFormatRgba8Unorm))
return type::ImageFormat::kRgba8Unorm;
if (match(Token::Type::kFormatRgba8UnormSrgb))
return type::ImageFormat::kRgba8UnormSrgb;
if (match(Token::Type::kFormatRgba8Snorm))
return type::ImageFormat::kRgba8Snorm;
if (match(Token::Type::kFormatRgba8Uint))
return type::ImageFormat::kRgba8Uint;
if (match(Token::Type::kFormatRgba8Sint))
return type::ImageFormat::kRgba8Sint;
if (match(Token::Type::kFormatBgra8Unorm))
return type::ImageFormat::kBgra8Unorm;
if (match(Token::Type::kFormatBgra8UnormSrgb))
return type::ImageFormat::kBgra8UnormSrgb;
if (match(Token::Type::kFormatRgb10A2Unorm))
return type::ImageFormat::kRgb10A2Unorm;
if (match(Token::Type::kFormatRg11B10Float))
return type::ImageFormat::kRg11B10Float;
if (match(Token::Type::kFormatRg32Uint))
return type::ImageFormat::kRg32Uint;
if (match(Token::Type::kFormatRg32Sint))
return type::ImageFormat::kRg32Sint;
if (match(Token::Type::kFormatRg32Float))
return type::ImageFormat::kRg32Float;
if (match(Token::Type::kFormatRgba16Uint))
return type::ImageFormat::kRgba16Uint;
if (match(Token::Type::kFormatRgba16Sint))
return type::ImageFormat::kRgba16Sint;
if (match(Token::Type::kFormatRgba16Float))
return type::ImageFormat::kRgba16Float;
if (match(Token::Type::kFormatRgba32Uint))
return type::ImageFormat::kRgba32Uint;
if (match(Token::Type::kFormatRgba32Sint))
return type::ImageFormat::kRgba32Sint;
if (match(Token::Type::kFormatRgba32Float))
return type::ImageFormat::kRgba32Float;
return add_error(peek().source(), "invalid format", use);
}
// variable_ident_decl
// : IDENT COLON variable_decoration_list* type_decl
Expect<ParserImpl::TypedIdentifier> ParserImpl::expect_variable_ident_decl(
const std::string& use) {
auto ident = expect_ident(use);
if (ident.errored)
return Failure::kErrored;
if (!expect(use, Token::Type::kColon))
return Failure::kErrored;
auto decos = decoration_list();
if (decos.errored)
return Failure::kErrored;
auto access_decos = take_decorations<ast::AccessDecoration>(decos.value);
auto t = peek();
auto type = type_decl(decos.value);
if (type.errored)
return Failure::kErrored;
if (!type.matched)
return add_error(t.source(), "invalid type", use);
if (!expect_decorations_consumed(decos.value))
return Failure::kErrored;
if (access_decos.size() > 1)
return add_error(ident.source, "multiple access decorations not allowed");
auto* ty = type.value;
for (auto* deco : access_decos) {
// If we have an access control decoration then we take it and wrap our
// type up with that decoration
ty = builder_.create<type::AccessControl>(
deco->As<ast::AccessDecoration>()->value(), ty);
}
return TypedIdentifier{ty, ident.value, ident.source};
}
Expect<ast::AccessControl> ParserImpl::expect_access_type() {
auto ident = expect_ident("access_type");
if (ident.errored)
return Failure::kErrored;
if (ident.value == kReadAccessControl)
return {ast::AccessControl::kReadOnly, ident.source};
if (ident.value == kWriteAccessControl)
return {ast::AccessControl::kWriteOnly, ident.source};
if (ident.value == kReadWriteAccessControl)
return {ast::AccessControl::kReadWrite, ident.source};
return add_error(ident.source, "invalid value for access decoration");
}
// variable_storage_decoration
// : LESS_THAN storage_class GREATER_THAN
Maybe<ast::StorageClass> ParserImpl::variable_storage_decoration() {
if (!peek().IsLessThan())
return Failure::kNoMatch;
const char* use = "variable decoration";
auto sc = expect_lt_gt_block(use, [&] { return expect_storage_class(use); });
if (sc.errored)
return Failure::kErrored;
return sc;
}
// type_alias
// : TYPE IDENT EQUAL type_decl
Maybe<type::Type*> ParserImpl::type_alias() {
auto t = peek();
if (!t.IsType())
return Failure::kNoMatch;
next(); // Consume the peek
const char* use = "type alias";
auto name = expect_ident(use);
if (name.errored)
return Failure::kErrored;
if (!expect(use, Token::Type::kEqual))
return Failure::kErrored;
auto type = type_decl();
if (type.errored)
return Failure::kErrored;
if (!type.matched)
return add_error(peek(), "invalid type alias");
auto* alias = builder_.create<type::Alias>(
builder_.Symbols().Register(name.value), type.value);
register_constructed(name.value, alias);
return alias;
}
// type_decl
// : IDENTIFIER
// | BOOL
// | FLOAT32
// | INT32
// | UINT32
// | VEC2 LESS_THAN type_decl GREATER_THAN
// | VEC3 LESS_THAN type_decl GREATER_THAN
// | VEC4 LESS_THAN type_decl GREATER_THAN
// | PTR LESS_THAN storage_class, type_decl GREATER_THAN
// | array_decoration_list* ARRAY LESS_THAN type_decl COMMA
// INT_LITERAL GREATER_THAN
// | array_decoration_list* ARRAY LESS_THAN type_decl
// GREATER_THAN
// | MAT2x2 LESS_THAN type_decl GREATER_THAN
// | MAT2x3 LESS_THAN type_decl GREATER_THAN
// | MAT2x4 LESS_THAN type_decl GREATER_THAN
// | MAT3x2 LESS_THAN type_decl GREATER_THAN
// | MAT3x3 LESS_THAN type_decl GREATER_THAN
// | MAT3x4 LESS_THAN type_decl GREATER_THAN
// | MAT4x2 LESS_THAN type_decl GREATER_THAN
// | MAT4x3 LESS_THAN type_decl GREATER_THAN
// | MAT4x4 LESS_THAN type_decl GREATER_THAN
// | texture_sampler_types
Maybe<type::Type*> ParserImpl::type_decl() {
auto decos = decoration_list();
if (decos.errored)
return Failure::kErrored;
auto type = type_decl(decos.value);
if (type.errored)
return Failure::kErrored;
if (!type.matched)
return Failure::kNoMatch;
if (!expect_decorations_consumed(decos.value))
return Failure::kErrored;
return type.value;
}
Maybe<type::Type*> ParserImpl::type_decl(ast::DecorationList& decos) {
auto t = peek();
if (match(Token::Type::kIdentifier)) {
auto* ty = get_constructed(t.to_str());
if (ty == nullptr)
return add_error(t, "unknown constructed type '" + t.to_str() + "'");
return ty;
}
if (match(Token::Type::kBool))
return builder_.create<type::Bool>();
if (match(Token::Type::kF32))
return builder_.create<type::F32>();
if (match(Token::Type::kI32))
return builder_.create<type::I32>();
if (match(Token::Type::kU32))
return builder_.create<type::U32>();
if (t.IsVec2() || t.IsVec3() || t.IsVec4()) {
next(); // Consume the peek
return expect_type_decl_vector(t);
}
if (match(Token::Type::kPtr))
return expect_type_decl_pointer();
if (match(Token::Type::kArray)) {
return expect_type_decl_array(std::move(decos));
}
if (t.IsMat2x2() || t.IsMat2x3() || t.IsMat2x4() || t.IsMat3x2() ||
t.IsMat3x3() || t.IsMat3x4() || t.IsMat4x2() || t.IsMat4x3() ||
t.IsMat4x4()) {
next(); // Consume the peek
return expect_type_decl_matrix(t);
}
auto texture_or_sampler = texture_sampler_types();
if (texture_or_sampler.errored)
return Failure::kErrored;
if (texture_or_sampler.matched)
return texture_or_sampler.value;
return Failure::kNoMatch;
}
Expect<type::Type*> ParserImpl::expect_type(const std::string& use) {
auto type = type_decl();
if (type.errored)
return Failure::kErrored;
if (!type.matched)
return add_error(peek().source(), "invalid type", use);
return type.value;
}
Expect<type::Type*> ParserImpl::expect_type_decl_pointer() {
const char* use = "ptr declaration";
return expect_lt_gt_block(use, [&]() -> Expect<type::Type*> {
auto sc = expect_storage_class(use);
if (sc.errored)
return Failure::kErrored;
if (!expect(use, Token::Type::kComma))
return Failure::kErrored;
auto subtype = expect_type(use);
if (subtype.errored)
return Failure::kErrored;
return builder_.create<type::Pointer>(subtype.value, sc.value);
});
}
Expect<type::Type*> ParserImpl::expect_type_decl_vector(Token t) {
uint32_t count = 2;
if (t.IsVec3())
count = 3;
else if (t.IsVec4())
count = 4;
const char* use = "vector";
auto subtype = expect_lt_gt_block(use, [&] { return expect_type(use); });
if (subtype.errored)
return Failure::kErrored;
return builder_.create<type::Vector>(subtype.value, count);
}
Expect<type::Type*> ParserImpl::expect_type_decl_array(
ast::DecorationList decos) {
const char* use = "array declaration";
return expect_lt_gt_block(use, [&]() -> Expect<type::Type*> {
auto subtype = expect_type(use);
if (subtype.errored)
return Failure::kErrored;
uint32_t size = 0;
if (match(Token::Type::kComma)) {
auto val = expect_nonzero_positive_sint("array size");
if (val.errored)
return Failure::kErrored;
size = val.value;
}
return create<type::Array>(subtype.value, size, std::move(decos));
});
}
Expect<type::Type*> ParserImpl::expect_type_decl_matrix(Token t) {
uint32_t rows = 2;
uint32_t columns = 2;
if (t.IsMat3x2() || t.IsMat3x3() || t.IsMat3x4()) {
columns = 3;
} else if (t.IsMat4x2() || t.IsMat4x3() || t.IsMat4x4()) {
columns = 4;
}
if (t.IsMat2x3() || t.IsMat3x3() || t.IsMat4x3()) {
rows = 3;
} else if (t.IsMat2x4() || t.IsMat3x4() || t.IsMat4x4()) {
rows = 4;
}
const char* use = "matrix";
auto subtype = expect_lt_gt_block(use, [&] { return expect_type(use); });
if (subtype.errored)
return Failure::kErrored;
return builder_.create<type::Matrix>(subtype.value, rows, columns);
}
// storage_class
// : INPUT
// | OUTPUT
// | UNIFORM
// | WORKGROUP
// | UNIFORM_CONSTANT
// | STORAGE
// | IMAGE
// | PRIVATE
// | FUNCTION
Expect<ast::StorageClass> ParserImpl::expect_storage_class(
const std::string& use) {
auto source = peek().source();
if (match(Token::Type::kIn))
return {ast::StorageClass::kInput, source};
if (match(Token::Type::kOut))
return {ast::StorageClass::kOutput, source};
if (match(Token::Type::kUniform))
return {ast::StorageClass::kUniform, source};
if (match(Token::Type::kWorkgroup))
return {ast::StorageClass::kWorkgroup, source};
if (match(Token::Type::kUniformConstant))
return {ast::StorageClass::kUniformConstant, source};
if (match(Token::Type::kStorage))
return {ast::StorageClass::kStorage, source};
if (match(Token::Type::kImage))
return {ast::StorageClass::kImage, source};
if (match(Token::Type::kPrivate))
return {ast::StorageClass::kPrivate, source};
if (match(Token::Type::kFunction))
return {ast::StorageClass::kFunction, source};
return add_error(source, "invalid storage class", use);
}
// struct_decl
// : struct_decoration_decl* STRUCT IDENT struct_body_decl
Maybe<type::Struct*> ParserImpl::struct_decl(ast::DecorationList& decos) {
auto t = peek();
auto source = t.source();
if (!match(Token::Type::kStruct))
return Failure::kNoMatch;
auto name = expect_ident("struct declaration");
if (name.errored)
return Failure::kErrored;
auto body = expect_struct_body_decl();
if (body.errored)
return Failure::kErrored;
return create<type::Struct>(
builder_.Symbols().Register(name.value),
create<ast::Struct>(source, std::move(body.value), std::move(decos)));
}
// struct_body_decl
// : BRACKET_LEFT struct_member* BRACKET_RIGHT
Expect<ast::StructMemberList> ParserImpl::expect_struct_body_decl() {
return expect_brace_block(
"struct declaration", [&]() -> Expect<ast::StructMemberList> {
bool errored = false;
ast::StructMemberList members;
while (synchronized_ && !peek().IsBraceRight() && !peek().IsEof()) {
auto member = sync(Token::Type::kSemicolon,
[&]() -> Expect<ast::StructMember*> {
auto decos = decoration_list();
if (decos.errored)
errored = true;
if (!synchronized_)
return Failure::kErrored;
return expect_struct_member(decos.value);
});
if (member.errored) {
errored = true;
} else {
members.push_back(member.value);
}
}
if (errored)
return Failure::kErrored;
return members;
});
}
// struct_member
// : struct_member_decoration_decl+ variable_ident_decl SEMICOLON
Expect<ast::StructMember*> ParserImpl::expect_struct_member(
ast::DecorationList& decos) {
auto decl = expect_variable_ident_decl("struct member");
if (decl.errored)
return Failure::kErrored;
if (!expect("struct member", Token::Type::kSemicolon))
return Failure::kErrored;
return create<ast::StructMember>(decl->source,
builder_.Symbols().Register(decl->name),
decl->type, std::move(decos));
}
// function_decl
// : function_header body_stmt
Maybe<ast::Function*> ParserImpl::function_decl(ast::DecorationList& decos) {
auto header = function_header();
if (header.errored) {
if (sync_to(Token::Type::kBraceLeft, /* consume: */ false)) {
// There were errors in the function header, but the parser has managed to
// resynchronize with the opening brace. As there's no outer
// synchronization token for function declarations, attempt to parse the
// function body. The AST isn't used as we've already errored, but this
// catches any errors inside the body, and can help keep the parser in
// sync.
expect_body_stmt();
}
return Failure::kErrored;
}
if (!header.matched)
return Failure::kNoMatch;
bool errored = false;
auto body = expect_body_stmt();
if (body.errored)
errored = true;
if (errored)
return Failure::kErrored;
return create<ast::Function>(
header->source, builder_.Symbols().Register(header->name), header->params,
header->return_type, body.value, decos);
}
// function_type_decl
// : type_decl
// | VOID
Maybe<type::Type*> ParserImpl::function_type_decl() {
if (match(Token::Type::kVoid))
return builder_.create<type::Void>();
return type_decl();
}
// function_header
// : FN IDENT PAREN_LEFT param_list PAREN_RIGHT ARROW function_type_decl
Maybe<ParserImpl::FunctionHeader> ParserImpl::function_header() {
Source source;
if (!match(Token::Type::kFn, &source))
return Failure::kNoMatch;
const char* use = "function declaration";
bool errored = false;
auto name = expect_ident(use);
if (name.errored) {
errored = true;
if (!sync_to(Token::Type::kParenLeft, /* consume: */ false))
return Failure::kErrored;
}
auto params = expect_paren_block(use, [&] { return expect_param_list(); });
if (params.errored) {
errored = true;
if (!synchronized_)
return Failure::kErrored;
}
if (!expect(use, Token::Type::kArrow))
return Failure::kErrored;
auto type = function_type_decl();
if (type.errored) {
errored = true;
} else if (!type.matched) {
return add_error(peek(), "unable to determine function return type");
}
if (errored)
return Failure::kErrored;
return FunctionHeader{source, name.value, std::move(params.value),
type.value};
}
// param_list
// :
// | (param COMMA)* param
Expect<ast::VariableList> ParserImpl::expect_param_list() {
// Check for an empty list.
auto t = peek();
if (!t.IsIdentifier() && !t.IsAttrLeft()) {
return ast::VariableList{};
}
ast::VariableList ret;
while (synchronized_) {
auto param = expect_param();
if (param.errored)
return Failure::kErrored;
ret.push_back(param.value);
if (!match(Token::Type::kComma))
break;
}
return ret;
}
// param
// : decoration_list* variable_ident_decl
Expect<ast::Variable*> ParserImpl::expect_param() {
auto decos = decoration_list();
auto decl = expect_variable_ident_decl("parameter");
if (decl.errored)
return Failure::kErrored;
auto* var =
create<ast::Variable>(decl->source, // source
builder_.Symbols().Register(decl->name), // symbol
ast::StorageClass::kNone, // storage_class
decl->type, // type
true, // is_const
nullptr, // constructor
std::move(decos.value)); // decorations
// Formal parameters are treated like a const declaration where the
// initializer value is provided by the call's argument. The key point is
// that it's not updatable after initially set. This is unlike C or GLSL
// which treat formal parameters like local variables that can be updated.
return var;
}
// pipeline_stage
// : VERTEX
// | FRAGMENT
// | COMPUTE
Expect<ast::PipelineStage> ParserImpl::expect_pipeline_stage() {
auto t = peek();
if (!t.IsIdentifier()) {
return add_error(t, "invalid value for stage decoration");
}
auto s = t.to_str();
if (s == kVertexStage) {
next(); // Consume the peek
return {ast::PipelineStage::kVertex, t.source()};
}
if (s == kFragmentStage) {
next(); // Consume the peek
return {ast::PipelineStage::kFragment, t.source()};
}
if (s == kComputeStage) {
next(); // Consume the peek
return {ast::PipelineStage::kCompute, t.source()};
}
return add_error(peek(), "invalid value for stage decoration");
}
Expect<ast::Builtin> ParserImpl::expect_builtin() {
auto ident = expect_ident("builtin");
if (ident.errored)
return Failure::kErrored;
ast::Builtin builtin = ident_to_builtin(ident.value);
if (builtin == ast::Builtin::kNone)
return add_error(ident.source, "invalid value for builtin decoration");
return {builtin, ident.source};
}
// body_stmt
// : BRACKET_LEFT statements BRACKET_RIGHT
Expect<ast::BlockStatement*> ParserImpl::expect_body_stmt() {
return expect_brace_block("", [&]() -> Expect<ast::BlockStatement*> {
auto stmts = expect_statements();
if (stmts.errored)
return Failure::kErrored;
return create<ast::BlockStatement>(Source{}, stmts.value);
});
}
// paren_rhs_stmt
// : PAREN_LEFT logical_or_expression PAREN_RIGHT
Expect<ast::Expression*> ParserImpl::expect_paren_rhs_stmt() {
return expect_paren_block("", [&]() -> Expect<ast::Expression*> {
auto expr = logical_or_expression();
if (expr.errored)
return Failure::kErrored;
if (!expr.matched)
return add_error(peek(), "unable to parse expression");
return expr.value;
});
}
// statements
// : statement*
Expect<ast::StatementList> ParserImpl::expect_statements() {
bool errored = false;
ast::StatementList stmts;
while (synchronized_) {
auto stmt = statement();
if (stmt.errored) {
errored = true;
} else if (stmt.matched) {
stmts.emplace_back(stmt.value);
} else {
break;
}
}
if (errored)
return Failure::kErrored;
return stmts;
}
// statement
// : SEMICOLON
// | body_stmt?
// | if_stmt
// | switch_stmt
// | loop_stmt
// | for_stmt
// | non_block_statement
// : return_stmt SEMICOLON
// | func_call_stmt SEMICOLON
// | variable_stmt SEMICOLON
// | break_stmt SEMICOLON
// | continue_stmt SEMICOLON
// | DISCARD SEMICOLON
// | assignment_stmt SEMICOLON
Maybe<ast::Statement*> ParserImpl::statement() {
while (match(Token::Type::kSemicolon)) {
// Skip empty statements
}
// Non-block statments that error can resynchronize on semicolon.
auto stmt =
sync(Token::Type::kSemicolon, [&] { return non_block_statement(); });
if (stmt.errored)
return Failure::kErrored;
if (stmt.matched)
return stmt;
auto stmt_if = if_stmt();
if (stmt_if.errored)
return Failure::kErrored;
if (stmt_if.matched)
return stmt_if.value;
auto sw = switch_stmt();
if (sw.errored)
return Failure::kErrored;
if (sw.matched)
return sw.value;
auto loop = loop_stmt();
if (loop.errored)
return Failure::kErrored;
if (loop.matched)
return loop.value;
auto stmt_for = for_stmt();
if (stmt_for.errored)
return Failure::kErrored;
if (stmt_for.matched)
return stmt_for.value;
if (peek().IsBraceLeft()) {
auto body = expect_body_stmt();
if (body.errored)
return Failure::kErrored;
return body.value;
}
return Failure::kNoMatch;
}
// statement (continued)
// : return_stmt SEMICOLON
// | func_call_stmt SEMICOLON
// | variable_stmt SEMICOLON
// | break_stmt SEMICOLON
// | continue_stmt SEMICOLON
// | DISCARD SEMICOLON
// | assignment_stmt SEMICOLON
Maybe<ast::Statement*> ParserImpl::non_block_statement() {
auto stmt = [&]() -> Maybe<ast::Statement*> {
auto ret_stmt = return_stmt();
if (ret_stmt.errored)
return Failure::kErrored;
if (ret_stmt.matched)
return ret_stmt.value;
auto func = func_call_stmt();
if (func.errored)
return Failure::kErrored;
if (func.matched)
return func.value;
auto var = variable_stmt();
if (var.errored)
return Failure::kErrored;
if (var.matched)
return var.value;
auto b = break_stmt();
if (b.errored)
return Failure::kErrored;
if (b.matched)
return b.value;
auto cont = continue_stmt();
if (cont.errored)
return Failure::kErrored;
if (cont.matched)
return cont.value;
auto assign = assignment_stmt();
if (assign.errored)
return Failure::kErrored;
if (assign.matched)
return assign.value;
Source source;
if (match(Token::Type::kDiscard, &source))
return create<ast::DiscardStatement>(source);
return Failure::kNoMatch;
}();
if (stmt.matched && !expect(stmt->Name(), Token::Type::kSemicolon))
return Failure::kErrored;
return stmt;
}
// return_stmt
// : RETURN logical_or_expression?
Maybe<ast::ReturnStatement*> ParserImpl::return_stmt() {
Source source;
if (!match(Token::Type::kReturn, &source))
return Failure::kNoMatch;
if (peek().IsSemicolon())
return create<ast::ReturnStatement>(source, nullptr);
auto expr = logical_or_expression();
if (expr.errored)
return Failure::kErrored;
// TODO(bclayton): Check matched?
return create<ast::ReturnStatement>(source, expr.value);
}
// variable_stmt
// : variable_decl
// | variable_decl EQUAL logical_or_expression
// | CONST variable_ident_decl EQUAL logical_or_expression
Maybe<ast::VariableDeclStatement*> ParserImpl::variable_stmt() {
if (match(Token::Type::kConst)) {
auto decl = expect_variable_ident_decl("constant declaration");
if (decl.errored)
return Failure::kErrored;
if (!expect("constant declaration", Token::Type::kEqual))
return Failure::kErrored;
auto constructor = logical_or_expression();
if (constructor.errored)
return Failure::kErrored;
if (!constructor.matched)
return add_error(peek(), "missing constructor for const declaration");
auto* var = create<ast::Variable>(
decl->source, // source
builder_.Symbols().Register(decl->name), // symbol
ast::StorageClass::kNone, // storage_class
decl->type, // type
true, // is_const
constructor.value, // constructor
ast::DecorationList{}); // decorations
return create<ast::VariableDeclStatement>(decl->source, var);
}
auto decl = variable_decl();
if (decl.errored)
return Failure::kErrored;
if (!decl.matched)
return Failure::kNoMatch;
ast::Expression* constructor = nullptr;
if (match(Token::Type::kEqual)) {
auto constructor_expr = logical_or_expression();
if (constructor_expr.errored)
return Failure::kErrored;
if (!constructor_expr.matched)
return add_error(peek(), "missing constructor for variable declaration");
constructor = constructor_expr.value;
}
auto* var =
create<ast::Variable>(decl->source, // source
builder_.Symbols().Register(decl->name), // symbol
decl->storage_class, // storage_class
decl->type, // type
false, // is_const
constructor, // constructor
ast::DecorationList{}); // decorations
return create<ast::VariableDeclStatement>(var->source(), var);
}
// if_stmt
// : IF paren_rhs_stmt body_stmt elseif_stmt? else_stmt?
Maybe<ast::IfStatement*> ParserImpl::if_stmt() {
Source source;
if (!match(Token::Type::kIf, &source))
return Failure::kNoMatch;
auto condition = expect_paren_rhs_stmt();
if (condition.errored)
return Failure::kErrored;
auto body = expect_body_stmt();
if (body.errored)
return Failure::kErrored;
auto elseif = elseif_stmt();
if (elseif.errored)
return Failure::kErrored;
auto el = else_stmt();
if (el.errored)
return Failure::kErrored;
if (el.matched)
elseif.value.push_back(el.value);
return create<ast::IfStatement>(source, condition.value, body.value,
elseif.value);
}
// elseif_stmt
// : ELSE_IF paren_rhs_stmt body_stmt elseif_stmt?
Maybe<ast::ElseStatementList> ParserImpl::elseif_stmt() {
Source source;
if (!match(Token::Type::kElseIf, &source))
return Failure::kNoMatch;
ast::ElseStatementList ret;
for (;;) {
auto condition = expect_paren_rhs_stmt();
if (condition.errored)
return Failure::kErrored;
auto body = expect_body_stmt();
if (body.errored)
return Failure::kErrored;
ret.push_back(
create<ast::ElseStatement>(source, condition.value, body.value));
if (!match(Token::Type::kElseIf, &source))
break;
}
return ret;
}
// else_stmt
// : ELSE body_stmt
Maybe<ast::ElseStatement*> ParserImpl::else_stmt() {
Source source;
if (!match(Token::Type::kElse, &source))
return Failure::kNoMatch;
auto body = expect_body_stmt();
if (body.errored)
return Failure::kErrored;
return create<ast::ElseStatement>(source, nullptr, body.value);
}
// switch_stmt
// : SWITCH paren_rhs_stmt BRACKET_LEFT switch_body+ BRACKET_RIGHT
Maybe<ast::SwitchStatement*> ParserImpl::switch_stmt() {
Source source;
if (!match(Token::Type::kSwitch, &source))
return Failure::kNoMatch;
auto condition = expect_paren_rhs_stmt();
if (condition.errored)
return Failure::kErrored;
auto body = expect_brace_block("switch statement",
[&]() -> Expect<ast::CaseStatementList> {
bool errored = false;
ast::CaseStatementList list;
while (synchronized_) {
auto stmt = switch_body();
if (stmt.errored) {
errored = true;
continue;
}
if (!stmt.matched)
break;
list.push_back(stmt.value);
}
if (errored)
return Failure::kErrored;
return list;
});
if (body.errored)
return Failure::kErrored;
return create<ast::SwitchStatement>(source, condition.value, body.value);
}
// switch_body
// : CASE case_selectors COLON BRACKET_LEFT case_body BRACKET_RIGHT
// | DEFAULT COLON BRACKET_LEFT case_body BRACKET_RIGHT
Maybe<ast::CaseStatement*> ParserImpl::switch_body() {
auto t = peek();
if (!t.IsCase() && !t.IsDefault())
return Failure::kNoMatch;
auto source = t.source();
next(); // Consume the peek
ast::CaseSelectorList selector_list;
if (t.IsCase()) {
auto selectors = expect_case_selectors();
if (selectors.errored)
return Failure::kErrored;
selector_list = std::move(selectors.value);
}
const char* use = "case statement";
if (!expect(use, Token::Type::kColon))
return Failure::kErrored;
auto body = expect_brace_block(use, [&] { return case_body(); });
if (body.errored)
return Failure::kErrored;
if (!body.matched)
return add_error(body.source, "expected case body");
return create<ast::CaseStatement>(source, selector_list, body.value);
}
// case_selectors
// : const_literal (COMMA const_literal)*
Expect<ast::CaseSelectorList> ParserImpl::expect_case_selectors() {
ast::CaseSelectorList selectors;
for (;;) {
auto t = peek();
auto matched_comma = match(Token::Type::kComma);
if (selectors.empty() && matched_comma)
return add_error(t, "a selector is expected before the comma");
if (matched_comma)
t = peek();
auto cond = const_literal();
if (cond.errored)
return Failure::kErrored;
if (!cond.matched) {
if (matched_comma) {
return add_error(t, "a selector is expected after the comma");
}
break;
}
if (!cond->Is<ast::IntLiteral>())
return add_error(t, "invalid case selector must be an integer value");
if (!selectors.empty() && !matched_comma)
return add_error(t, "expected a comma after the previous selector");
selectors.push_back(cond.value->As<ast::IntLiteral>());
}
if (selectors.empty())
return add_error(peek(), "unable to parse case selectors");
return selectors;
}
// case_body
// :
// | statement case_body
// | FALLTHROUGH SEMICOLON
Maybe<ast::BlockStatement*> ParserImpl::case_body() {
ast::StatementList stmts;
for (;;) {
Source source;
if (match(Token::Type::kFallthrough, &source)) {
if (!expect("fallthrough statement", Token::Type::kSemicolon))
return Failure::kErrored;
stmts.emplace_back(create<ast::FallthroughStatement>(source));
break;
}
auto stmt = statement();
if (stmt.errored)
return Failure::kErrored;
if (!stmt.matched)
break;
stmts.emplace_back(stmt.value);
}
return create<ast::BlockStatement>(Source{}, stmts);
}
// loop_stmt
// : LOOP BRACKET_LEFT statements continuing_stmt? BRACKET_RIGHT
Maybe<ast::LoopStatement*> ParserImpl::loop_stmt() {
Source source;
if (!match(Token::Type::kLoop, &source))
return Failure::kNoMatch;
return expect_brace_block("loop", [&]() -> Maybe<ast::LoopStatement*> {
auto stmts = expect_statements();
if (stmts.errored)
return Failure::kErrored;
auto continuing = continuing_stmt();
if (continuing.errored)
return Failure::kErrored;
auto* body = create<ast::BlockStatement>(source, stmts.value);
return create<ast::LoopStatement>(source, body, continuing.value);
});
}
ForHeader::ForHeader(ast::Statement* init,
ast::Expression* cond,
ast::Statement* cont)
: initializer(init), condition(cond), continuing(cont) {}
ForHeader::~ForHeader() = default;
// (variable_stmt | assignment_stmt | func_call_stmt)?
Maybe<ast::Statement*> ParserImpl::for_header_initializer() {
auto call = func_call_stmt();
if (call.errored)
return Failure::kErrored;
if (call.matched)
return call.value;
auto var = variable_stmt();
if (var.errored)
return Failure::kErrored;
if (var.matched)
return var.value;
auto assign = assignment_stmt();
if (assign.errored)
return Failure::kErrored;
if (assign.matched)
return assign.value;
return Failure::kNoMatch;
}
// (assignment_stmt | func_call_stmt)?
Maybe<ast::Statement*> ParserImpl::for_header_continuing() {
auto call_stmt = func_call_stmt();
if (call_stmt.errored)
return Failure::kErrored;
if (call_stmt.matched)
return call_stmt.value;
auto assign = assignment_stmt();
if (assign.errored)
return Failure::kErrored;
if (assign.matched)
return assign.value;
return Failure::kNoMatch;
}
// for_header
// : (variable_stmt | assignment_stmt | func_call_stmt)?
// SEMICOLON
// logical_or_expression? SEMICOLON
// (assignment_stmt | func_call_stmt)?
Expect<std::unique_ptr<ForHeader>> ParserImpl::expect_for_header() {
auto initializer = for_header_initializer();
if (initializer.errored)
return Failure::kErrored;
if (!expect("initializer in for loop", Token::Type::kSemicolon))
return Failure::kErrored;
auto condition = logical_or_expression();
if (condition.errored)
return Failure::kErrored;
if (!expect("condition in for loop", Token::Type::kSemicolon))
return Failure::kErrored;
auto continuing = for_header_continuing();
if (continuing.errored)
return Failure::kErrored;
return std::make_unique<ForHeader>(initializer.value, condition.value,
continuing.value);
}
// for_statement
// : FOR PAREN_LEFT for_header PAREN_RIGHT BRACE_LEFT statements BRACE_RIGHT
Maybe<ast::Statement*> ParserImpl::for_stmt() {
Source source;
if (!match(Token::Type::kFor, &source))
return Failure::kNoMatch;
auto header =
expect_paren_block("for loop", [&] { return expect_for_header(); });
if (header.errored)
return Failure::kErrored;
auto stmts =
expect_brace_block("for loop", [&] { return expect_statements(); });
if (stmts.errored)
return Failure::kErrored;
// The for statement is a syntactic sugar on top of the loop statement.
// We create corresponding nodes in ast with the exact same behaviour
// as we would expect from the loop statement.
if (header->condition != nullptr) {
// !condition
auto* not_condition = create<ast::UnaryOpExpression>(
header->condition->source(), ast::UnaryOp::kNot, header->condition);
// { break; }
auto* break_stmt = create<ast::BreakStatement>(not_condition->source());
auto* break_body =
create<ast::BlockStatement>(not_condition->source(), ast::StatementList{
break_stmt,
});
// if (!condition) { break; }
auto* break_if_not_condition =
create<ast::IfStatement>(not_condition->source(), not_condition,
break_body, ast::ElseStatementList{});
stmts.value.insert(stmts.value.begin(), break_if_not_condition);
}
ast::BlockStatement* continuing_body = nullptr;
if (header->continuing != nullptr) {
continuing_body = create<ast::BlockStatement>(header->continuing->source(),
ast::StatementList{
header->continuing,
});
}
auto* body = create<ast::BlockStatement>(source, stmts.value);
auto* loop = create<ast::LoopStatement>(source, body, continuing_body);
if (header->initializer != nullptr) {
return create<ast::BlockStatement>(source, ast::StatementList{
header->initializer,
loop,
});
}
return loop;
}
// func_call_stmt
// : IDENT PAREN_LEFT argument_expression_list* PAREN_RIGHT
Maybe<ast::CallStatement*> ParserImpl::func_call_stmt() {
auto t = peek();
auto t2 = peek(1);
if (!t.IsIdentifier() || !t2.IsParenLeft())
return Failure::kNoMatch;
auto source = t.source();
next(); // Consume the peek
next(); // Consume the 2nd peek
auto name = t.to_str();
ast::ExpressionList params;
t = peek();
if (!t.IsParenRight() && !t.IsEof()) {
auto list = expect_argument_expression_list();
if (list.errored)
return Failure::kErrored;
params = std::move(list.value);
}
if (!expect("call statement", Token::Type::kParenRight))
return Failure::kErrored;
return create<ast::CallStatement>(
Source{}, create<ast::CallExpression>(
source,
create<ast::IdentifierExpression>(
source, builder_.Symbols().Register(name)),
std::move(params)));
}
// break_stmt
// : BREAK
Maybe<ast::BreakStatement*> ParserImpl::break_stmt() {
Source source;
if (!match(Token::Type::kBreak, &source))
return Failure::kNoMatch;
return create<ast::BreakStatement>(source);
}
// continue_stmt
// : CONTINUE
Maybe<ast::ContinueStatement*> ParserImpl::continue_stmt() {
Source source;
if (!match(Token::Type::kContinue, &source))
return Failure::kNoMatch;
return create<ast::ContinueStatement>(source);
}
// continuing_stmt
// : CONTINUING body_stmt
Maybe<ast::BlockStatement*> ParserImpl::continuing_stmt() {
if (!match(Token::Type::kContinuing))
return create<ast::BlockStatement>(Source{}, ast::StatementList{});
return expect_body_stmt();
}
// primary_expression
// : IDENT
// | type_decl PAREN_LEFT argument_expression_list* PAREN_RIGHT
// | const_literal
// | paren_rhs_stmt
// | BITCAST LESS_THAN type_decl GREATER_THAN paren_rhs_stmt
Maybe<ast::Expression*> ParserImpl::primary_expression() {
auto t = peek();
auto source = t.source();
auto lit = const_literal();
if (lit.errored)
return Failure::kErrored;
if (lit.matched)
return create<ast::ScalarConstructorExpression>(source, lit.value);
if (t.IsParenLeft()) {
auto paren = expect_paren_rhs_stmt();
if (paren.errored)
return Failure::kErrored;
return paren.value;
}
if (match(Token::Type::kBitcast)) {
const char* use = "bitcast expression";
auto type = expect_lt_gt_block(use, [&] { return expect_type(use); });
if (type.errored)
return Failure::kErrored;
auto params = expect_paren_rhs_stmt();
if (params.errored)
return Failure::kErrored;
return create<ast::BitcastExpression>(source, type.value, params.value);
}
if (t.IsIdentifier() && !get_constructed(t.to_str())) {
next();
return create<ast::IdentifierExpression>(
t.source(), builder_.Symbols().Register(t.to_str()));
}
auto type = type_decl();
if (type.errored)
return Failure::kErrored;
if (type.matched) {
auto expr = expect_paren_block(
"type constructor", [&]() -> Expect<ast::TypeConstructorExpression*> {
t = peek();
if (t.IsParenRight() || t.IsEof())
return create<ast::TypeConstructorExpression>(
source, type.value, ast::ExpressionList{});
auto params = expect_argument_expression_list();
if (params.errored)
return Failure::kErrored;
return create<ast::TypeConstructorExpression>(source, type.value,
params.value);
});
if (expr.errored)
return Failure::kErrored;
return expr.value;
}
return Failure::kNoMatch;
}
// postfix_expr
// :
// | BRACE_LEFT logical_or_expression BRACE_RIGHT postfix_expr
// | PAREN_LEFT argument_expression_list* PAREN_RIGHT postfix_expr
// | PERIOD IDENTIFIER postfix_expr
Maybe<ast::Expression*> ParserImpl::postfix_expr(ast::Expression* prefix) {
Source source;
if (match(Token::Type::kBracketLeft, &source)) {
return sync(Token::Type::kBracketRight, [&]() -> Maybe<ast::Expression*> {
auto param = logical_or_expression();
if (param.errored)
return Failure::kErrored;
if (!param.matched)
return add_error(peek(), "unable to parse expression inside []");
if (!expect("array accessor", Token::Type::kBracketRight))
return Failure::kErrored;
return postfix_expr(
create<ast::ArrayAccessorExpression>(source, prefix, param.value));
});
}
if (match(Token::Type::kParenLeft, &source)) {
return sync(Token::Type::kParenRight, [&]() -> Maybe<ast::Expression*> {
ast::ExpressionList params;
auto t = peek();
if (!t.IsParenRight() && !t.IsEof()) {
auto list = expect_argument_expression_list();
if (list.errored)
return Failure::kErrored;
params = list.value;
}
if (!expect("call expression", Token::Type::kParenRight))
return Failure::kErrored;
return postfix_expr(create<ast::CallExpression>(source, prefix, params));
});
}
if (match(Token::Type::kPeriod)) {
auto ident = expect_ident("member accessor");
if (ident.errored)
return Failure::kErrored;
return postfix_expr(create<ast::MemberAccessorExpression>(
ident.source, prefix,
create<ast::IdentifierExpression>(
ident.source, builder_.Symbols().Register(ident.value))));
}
return prefix;
}
// postfix_expression
// : primary_expression postfix_expr
Maybe<ast::Expression*> ParserImpl::postfix_expression() {
auto prefix = primary_expression();
if (prefix.errored)
return Failure::kErrored;
if (!prefix.matched)
return Failure::kNoMatch;
return postfix_expr(prefix.value);
}
// argument_expression_list
// : (logical_or_expression COMMA)* logical_or_expression
Expect<ast::ExpressionList> ParserImpl::expect_argument_expression_list() {
auto arg = logical_or_expression();
if (arg.errored)
return Failure::kErrored;
if (!arg.matched)
return add_error(peek(), "unable to parse argument expression");
ast::ExpressionList ret;
ret.push_back(arg.value);
while (match(Token::Type::kComma)) {
arg = logical_or_expression();
if (arg.errored)
return Failure::kErrored;
if (!arg.matched) {
return add_error(peek(),
"unable to parse argument expression after comma");
}
ret.push_back(arg.value);
}
return ret;
}
// unary_expression
// : postfix_expression
// | MINUS unary_expression
// | BANG unary_expression
Maybe<ast::Expression*> ParserImpl::unary_expression() {
auto t = peek();
auto source = t.source();
if (t.IsMinus() || t.IsBang()) {
auto name = t.to_name();
next(); // Consume the peek
auto op = ast::UnaryOp::kNegation;
if (t.IsBang())
op = ast::UnaryOp::kNot;
auto expr = unary_expression();
if (expr.errored)
return Failure::kErrored;
if (!expr.matched)
return add_error(peek(),
"unable to parse right side of " + name + " expression");
return create<ast::UnaryOpExpression>(source, op, expr.value);
}
return postfix_expression();
}
// multiplicative_expr
// :
// | STAR unary_expression multiplicative_expr
// | FORWARD_SLASH unary_expression multiplicative_expr
// | MODULO unary_expression multiplicative_expr
Expect<ast::Expression*> ParserImpl::expect_multiplicative_expr(
ast::Expression* lhs) {
while (synchronized_) {
auto t = peek();
ast::BinaryOp op = ast::BinaryOp::kNone;
if (t.IsStar())
op = ast::BinaryOp::kMultiply;
else if (t.IsForwardSlash())
op = ast::BinaryOp::kDivide;
else if (t.IsMod())
op = ast::BinaryOp::kModulo;
else
return lhs;
auto source = t.source();
auto name = t.to_name();
next(); // Consume the peek
auto rhs = unary_expression();
if (rhs.errored)
return Failure::kErrored;
if (!rhs.matched) {
return add_error(peek(),
"unable to parse right side of " + name + " expression");
}
lhs = create<ast::BinaryExpression>(source, op, lhs, rhs.value);
}
return Failure::kErrored;
}
// multiplicative_expression
// : unary_expression multiplicative_expr
Maybe<ast::Expression*> ParserImpl::multiplicative_expression() {
auto lhs = unary_expression();
if (lhs.errored)
return Failure::kErrored;
if (!lhs.matched)
return Failure::kNoMatch;
return expect_multiplicative_expr(lhs.value);
}
// additive_expr
// :
// | PLUS multiplicative_expression additive_expr
// | MINUS multiplicative_expression additive_expr
Expect<ast::Expression*> ParserImpl::expect_additive_expr(
ast::Expression* lhs) {
while (synchronized_) {
auto t = peek();
ast::BinaryOp op = ast::BinaryOp::kNone;
if (t.IsPlus())
op = ast::BinaryOp::kAdd;
else if (t.IsMinus())
op = ast::BinaryOp::kSubtract;
else
return lhs;
auto source = t.source();
next(); // Consume the peek
auto rhs = multiplicative_expression();
if (rhs.errored)
return Failure::kErrored;
if (!rhs.matched)
return add_error(peek(), "unable to parse right side of + expression");
lhs = create<ast::BinaryExpression>(source, op, lhs, rhs.value);
}
return Failure::kErrored;
}
// additive_expression
// : multiplicative_expression additive_expr
Maybe<ast::Expression*> ParserImpl::additive_expression() {
auto lhs = multiplicative_expression();
if (lhs.errored)
return Failure::kErrored;
if (!lhs.matched)
return Failure::kNoMatch;
return expect_additive_expr(lhs.value);
}
// shift_expr
// :
// | SHIFT_LEFT additive_expression shift_expr
// | SHIFT_RIGHT additive_expression shift_expr
Expect<ast::Expression*> ParserImpl::expect_shift_expr(ast::Expression* lhs) {
while (synchronized_) {
auto t = peek();
auto source = t.source();
auto* name = "";
ast::BinaryOp op = ast::BinaryOp::kNone;
if (t.IsShiftLeft()) {
next(); // Consume the peek
op = ast::BinaryOp::kShiftLeft;
name = "<<";
} else if (t.IsShiftRight()) {
next(); // Consume the peek
op = ast::BinaryOp::kShiftRight;
name = ">>";
} else {
return lhs;
}
auto rhs = additive_expression();
if (rhs.errored)
return Failure::kErrored;
if (!rhs.matched) {
return add_error(peek(), std::string("unable to parse right side of ") +
name + " expression");
}
return lhs = create<ast::BinaryExpression>(source, op, lhs, rhs.value);
}
return Failure::kErrored;
}
// shift_expression
// : additive_expression shift_expr
Maybe<ast::Expression*> ParserImpl::shift_expression() {
auto lhs = additive_expression();
if (lhs.errored)
return Failure::kErrored;
if (!lhs.matched)
return Failure::kNoMatch;
return expect_shift_expr(lhs.value);
}
// relational_expr
// :
// | LESS_THAN shift_expression relational_expr
// | GREATER_THAN shift_expression relational_expr
// | LESS_THAN_EQUAL shift_expression relational_expr
// | GREATER_THAN_EQUAL shift_expression relational_expr
Expect<ast::Expression*> ParserImpl::expect_relational_expr(
ast::Expression* lhs) {
while (synchronized_) {
auto t = peek();
ast::BinaryOp op = ast::BinaryOp::kNone;
if (t.IsLessThan())
op = ast::BinaryOp::kLessThan;
else if (t.IsGreaterThan())
op = ast::BinaryOp::kGreaterThan;
else if (t.IsLessThanEqual())
op = ast::BinaryOp::kLessThanEqual;
else if (t.IsGreaterThanEqual())
op = ast::BinaryOp::kGreaterThanEqual;
else
return lhs;
auto source = t.source();
auto name = t.to_name();
next(); // Consume the peek
auto rhs = shift_expression();
if (rhs.errored)
return Failure::kErrored;
if (!rhs.matched) {
return add_error(peek(),
"unable to parse right side of " + name + " expression");
}
lhs = create<ast::BinaryExpression>(source, op, lhs, rhs.value);
}
return Failure::kErrored;
}
// relational_expression
// : shift_expression relational_expr
Maybe<ast::Expression*> ParserImpl::relational_expression() {
auto lhs = shift_expression();
if (lhs.errored)
return Failure::kErrored;
if (!lhs.matched)
return Failure::kNoMatch;
return expect_relational_expr(lhs.value);
}
// equality_expr
// :
// | EQUAL_EQUAL relational_expression equality_expr
// | NOT_EQUAL relational_expression equality_expr
Expect<ast::Expression*> ParserImpl::expect_equality_expr(
ast::Expression* lhs) {
while (synchronized_) {
auto t = peek();
ast::BinaryOp op = ast::BinaryOp::kNone;
if (t.IsEqualEqual())
op = ast::BinaryOp::kEqual;
else if (t.IsNotEqual())
op = ast::BinaryOp::kNotEqual;
else
return lhs;
auto source = t.source();
auto name = t.to_name();
next(); // Consume the peek
auto rhs = relational_expression();
if (rhs.errored)
return Failure::kErrored;
if (!rhs.matched) {
return add_error(peek(),
"unable to parse right side of " + name + " expression");
}
lhs = create<ast::BinaryExpression>(source, op, lhs, rhs.value);
}
return Failure::kErrored;
}
// equality_expression
// : relational_expression equality_expr
Maybe<ast::Expression*> ParserImpl::equality_expression() {
auto lhs = relational_expression();
if (lhs.errored)
return Failure::kErrored;
if (!lhs.matched)
return Failure::kNoMatch;
return expect_equality_expr(lhs.value);
}
// and_expr
// :
// | AND equality_expression and_expr
Expect<ast::Expression*> ParserImpl::expect_and_expr(ast::Expression* lhs) {
while (synchronized_) {
auto t = peek();
if (!t.IsAnd())
return lhs;
auto source = t.source();
next(); // Consume the peek
auto rhs = equality_expression();
if (rhs.errored)
return Failure::kErrored;
if (!rhs.matched)
return add_error(peek(), "unable to parse right side of & expression");
lhs = create<ast::BinaryExpression>(source, ast::BinaryOp::kAnd, lhs,
rhs.value);
}
return Failure::kErrored;
}
// and_expression
// : equality_expression and_expr
Maybe<ast::Expression*> ParserImpl::and_expression() {
auto lhs = equality_expression();
if (lhs.errored)
return Failure::kErrored;
if (!lhs.matched)
return Failure::kNoMatch;
return expect_and_expr(lhs.value);
}
// exclusive_or_expr
// :
// | XOR and_expression exclusive_or_expr
Expect<ast::Expression*> ParserImpl::expect_exclusive_or_expr(
ast::Expression* lhs) {
while (synchronized_) {
Source source;
if (!match(Token::Type::kXor, &source))
return lhs;
auto rhs = and_expression();
if (rhs.errored)
return Failure::kErrored;
if (!rhs.matched)
return add_error(peek(), "unable to parse right side of ^ expression");
lhs = create<ast::BinaryExpression>(source, ast::BinaryOp::kXor, lhs,
rhs.value);
}
return Failure::kErrored;
}
// exclusive_or_expression
// : and_expression exclusive_or_expr
Maybe<ast::Expression*> ParserImpl::exclusive_or_expression() {
auto lhs = and_expression();
if (lhs.errored)
return Failure::kErrored;
if (!lhs.matched)
return Failure::kNoMatch;
return expect_exclusive_or_expr(lhs.value);
}
// inclusive_or_expr
// :
// | OR exclusive_or_expression inclusive_or_expr
Expect<ast::Expression*> ParserImpl::expect_inclusive_or_expr(
ast::Expression* lhs) {
while (synchronized_) {
Source source;
if (!match(Token::Type::kOr))
return lhs;
auto rhs = exclusive_or_expression();
if (rhs.errored)
return Failure::kErrored;
if (!rhs.matched)
return add_error(peek(), "unable to parse right side of | expression");
lhs = create<ast::BinaryExpression>(source, ast::BinaryOp::kOr, lhs,
rhs.value);
}
return Failure::kErrored;
}
// inclusive_or_expression
// : exclusive_or_expression inclusive_or_expr
Maybe<ast::Expression*> ParserImpl::inclusive_or_expression() {
auto lhs = exclusive_or_expression();
if (lhs.errored)
return Failure::kErrored;
if (!lhs.matched)
return Failure::kNoMatch;
return expect_inclusive_or_expr(lhs.value);
}
// logical_and_expr
// :
// | AND_AND inclusive_or_expression logical_and_expr
Expect<ast::Expression*> ParserImpl::expect_logical_and_expr(
ast::Expression* lhs) {
while (synchronized_) {
auto t = peek();
if (!t.IsAndAnd())
return lhs;
auto source = t.source();
next(); // Consume the peek
auto rhs = inclusive_or_expression();
if (rhs.errored)
return Failure::kErrored;
if (!rhs.matched)
return add_error(peek(), "unable to parse right side of && expression");
lhs = create<ast::BinaryExpression>(source, ast::BinaryOp::kLogicalAnd, lhs,
rhs.value);
}
return Failure::kErrored;
}
// logical_and_expression
// : inclusive_or_expression logical_and_expr
Maybe<ast::Expression*> ParserImpl::logical_and_expression() {
auto lhs = inclusive_or_expression();
if (lhs.errored)
return Failure::kErrored;
if (!lhs.matched)
return Failure::kNoMatch;
return expect_logical_and_expr(lhs.value);
}
// logical_or_expr
// :
// | OR_OR logical_and_expression logical_or_expr
Expect<ast::Expression*> ParserImpl::expect_logical_or_expr(
ast::Expression* lhs) {
while (synchronized_) {
Source source;
if (!match(Token::Type::kOrOr))
return lhs;
auto rhs = logical_and_expression();
if (rhs.errored)
return Failure::kErrored;
if (!rhs.matched)
return add_error(peek(), "unable to parse right side of || expression");
lhs = create<ast::BinaryExpression>(source, ast::BinaryOp::kLogicalOr, lhs,
rhs.value);
}
return Failure::kErrored;
}
// logical_or_expression
// : logical_and_expression logical_or_expr
Maybe<ast::Expression*> ParserImpl::logical_or_expression() {
auto lhs = logical_and_expression();
if (lhs.errored)
return Failure::kErrored;
if (!lhs.matched)
return Failure::kNoMatch;
return expect_logical_or_expr(lhs.value);
}
// assignment_stmt
// : unary_expression EQUAL logical_or_expression
Maybe<ast::AssignmentStatement*> ParserImpl::assignment_stmt() {
auto t = peek();
auto source = t.source();
// tint:295 - Test for `ident COLON` - this is invalid grammar, and without
// special casing will error as "missing = for assignment", which is less
// helpful than this error message:
if (peek(0).IsIdentifier() && peek(1).IsColon()) {
return add_error(peek(0).source(),
"expected 'var' for variable declaration");
}
auto lhs = unary_expression();
if (lhs.errored)
return Failure::kErrored;
if (!lhs.matched)
return Failure::kNoMatch;
if (!expect("assignment", Token::Type::kEqual))
return Failure::kErrored;
auto rhs = logical_or_expression();
if (rhs.errored)
return Failure::kErrored;
if (!rhs.matched)
return add_error(peek(), "unable to parse right side of assignment");
return create<ast::AssignmentStatement>(source, lhs.value, rhs.value);
}
// const_literal
// : INT_LITERAL
// | UINT_LITERAL
// | FLOAT_LITERAL
// | TRUE
// | FALSE
Maybe<ast::Literal*> ParserImpl::const_literal() {
auto t = peek();
if (match(Token::Type::kTrue)) {
auto* type = builder_.create<type::Bool>();
return create<ast::BoolLiteral>(Source{}, type, true);
}
if (match(Token::Type::kFalse)) {
auto* type = builder_.create<type::Bool>();
return create<ast::BoolLiteral>(Source{}, type, false);
}
if (match(Token::Type::kSintLiteral)) {
auto* type = builder_.create<type::I32>();
return create<ast::SintLiteral>(Source{}, type, t.to_i32());
}
if (match(Token::Type::kUintLiteral)) {
auto* type = builder_.create<type::U32>();
return create<ast::UintLiteral>(Source{}, type, t.to_u32());
}
if (match(Token::Type::kFloatLiteral)) {
auto p = peek();
if (p.IsIdentifier() && p.to_str() == "f") {
next(); // Consume 'f'
add_error(p.source(), "float literals must not be suffixed with 'f'");
}
auto* type = builder_.create<type::F32>();
return create<ast::FloatLiteral>(Source{}, type, t.to_f32());
}
return Failure::kNoMatch;
}
// const_expr
// : type_decl PAREN_LEFT (const_expr COMMA)? const_expr PAREN_RIGHT
// | const_literal
Expect<ast::ConstructorExpression*> ParserImpl::expect_const_expr() {
auto t = peek();
auto source = t.source();
auto type = type_decl();
if (type.errored)
return Failure::kErrored;
if (type.matched) {
auto params = expect_paren_block("type constructor",
[&]() -> Expect<ast::ExpressionList> {
ast::ExpressionList list;
auto param = expect_const_expr();
if (param.errored)
return Failure::kErrored;
list.emplace_back(param.value);
while (match(Token::Type::kComma)) {
param = expect_const_expr();
if (param.errored)
return Failure::kErrored;
list.emplace_back(param.value);
}
return list;
});
if (params.errored)
return Failure::kErrored;
return create<ast::TypeConstructorExpression>(source, type.value,
params.value);
}
auto lit = const_literal();
if (lit.errored)
return Failure::kErrored;
if (!lit.matched)
return add_error(peek(), "unable to parse const literal");
return create<ast::ScalarConstructorExpression>(source, lit.value);
}
Maybe<ast::DecorationList> ParserImpl::decoration_list() {
bool errored = false;
bool matched = false;
ast::DecorationList decos;
while (synchronized_) {
auto list = decoration_bracketed_list(decos);
if (list.errored)
errored = true;
if (!list.matched)
break;
matched = true;
}
if (errored)
return Failure::kErrored;
if (!matched)
return Failure::kNoMatch;
return decos;
}
Maybe<bool> ParserImpl::decoration_bracketed_list(ast::DecorationList& decos) {
const char* use = "decoration list";
if (!match(Token::Type::kAttrLeft)) {
return Failure::kNoMatch;
}
Source source;
if (match(Token::Type::kAttrRight, &source))
return add_error(source, "empty decoration list");
return sync(Token::Type::kAttrRight, [&]() -> Expect<bool> {
bool errored = false;
while (synchronized_) {
auto deco = expect_decoration();
if (deco.errored)
errored = true;
decos.emplace_back(deco.value);
if (match(Token::Type::kComma))
continue;
if (is_decoration(peek())) {
// We have two decorations in a bracket without a separating comma.
// e.g. [[location(1) group(2)]]
// ^^^ expected comma
expect(use, Token::Type::kComma);
return Failure::kErrored;
}
break;
}
if (errored)
return Failure::kErrored;
if (!expect(use, Token::Type::kAttrRight))
return Failure::kErrored;
return true;
});
}
Expect<ast::Decoration*> ParserImpl::expect_decoration() {
auto t = peek();
auto deco = decoration();
if (deco.errored)
return Failure::kErrored;
if (deco.matched)
return deco.value;
return add_error(t, "expected decoration");
}
Maybe<ast::Decoration*> ParserImpl::decoration() {
using Result = Maybe<ast::Decoration*>;
auto t = next();
if (!t.IsIdentifier()) {
return Failure::kNoMatch;
}
auto s = t.to_str();
if (s == kAccessDecoration) {
const char* use = "access decoration";
return expect_paren_block(use, [&]() -> Result {
auto val = expect_access_type();
if (val.errored)
return Failure::kErrored;
return create<ast::AccessDecoration>(t.source(), val.value);
});
}
if (s == kLocationDecoration) {
const char* use = "location decoration";
return expect_paren_block(use, [&]() -> Result {
auto val = expect_positive_sint(use);
if (val.errored)
return Failure::kErrored;
return create<ast::LocationDecoration>(t.source(), val.value);
});
}
if (s == kBindingDecoration) {
const char* use = "binding decoration";
return expect_paren_block(use, [&]() -> Result {
auto val = expect_positive_sint(use);
if (val.errored)
return Failure::kErrored;
return create<ast::BindingDecoration>(t.source(), val.value);
});
}
if (s == kSetDecoration || s == kGroupDecoration) {
const char* use = "group decoration";
return expect_paren_block(use, [&]() -> Result {
auto val = expect_positive_sint(use);
if (val.errored)
return Failure::kErrored;
return create<ast::GroupDecoration>(t.source(), val.value);
});
}
if (s == kBuiltinDecoration) {
return expect_paren_block("builtin decoration", [&]() -> Result {
auto builtin = expect_builtin();
if (builtin.errored)
return Failure::kErrored;
return create<ast::BuiltinDecoration>(t.source(), builtin.value);
});
}
if (s == kWorkgroupSizeDecoration) {
return expect_paren_block("workgroup_size decoration", [&]() -> Result {
uint32_t x;
uint32_t y = 1;
uint32_t z = 1;
auto val = expect_nonzero_positive_sint("workgroup_size x parameter");
if (val.errored)
return Failure::kErrored;
x = val.value;
if (match(Token::Type::kComma)) {
val = expect_nonzero_positive_sint("workgroup_size y parameter");
if (val.errored)
return Failure::kErrored;
y = val.value;
if (match(Token::Type::kComma)) {
val = expect_nonzero_positive_sint("workgroup_size z parameter");
if (val.errored)
return Failure::kErrored;
z = val.value;
}
}
return create<ast::WorkgroupDecoration>(t.source(), x, y, z);
});
}
if (s == kStageDecoration) {
return expect_paren_block("stage decoration", [&]() -> Result {
auto stage = expect_pipeline_stage();
if (stage.errored)
return Failure::kErrored;
return create<ast::StageDecoration>(t.source(), stage.value);
});
}
if (s == kBlockDecoration) {
return create<ast::StructBlockDecoration>(t.source());
}
if (s == kStrideDecoration) {
const char* use = "stride decoration";
return expect_paren_block(use, [&]() -> Result {
auto val = expect_nonzero_positive_sint(use);
if (val.errored)
return Failure::kErrored;
return create<ast::StrideDecoration>(t.source(), val.value);
});
}
if (s == kOffsetDecoration) {
const char* use = "offset decoration";
return expect_paren_block(use, [&]() -> Result {
auto val = expect_positive_sint(use);
if (val.errored)
return Failure::kErrored;
return create<ast::StructMemberOffsetDecoration>(t.source(), val.value);
});
}
if (s == kConstantIdDecoration) {
const char* use = "constant_id decoration";
return expect_paren_block(use, [&]() -> Result {
auto val = expect_positive_sint(use);
if (val.errored)
return Failure::kErrored;
return create<ast::ConstantIdDecoration>(t.source(), val.value);
});
}
return Failure::kNoMatch;
}
template <typename T>
std::vector<T*> ParserImpl::take_decorations(ast::DecorationList& in) {
ast::DecorationList remaining;
std::vector<T*> out;
out.reserve(in.size());
for (auto* deco : in) {
if (auto* t = deco->As<T>()) {
out.emplace_back(t);
} else {
remaining.emplace_back(deco);
}
}
in = std::move(remaining);
return out;
}
bool ParserImpl::expect_decorations_consumed(const ast::DecorationList& in) {
if (in.empty()) {
return true;
}
add_error(in[0]->source(), "unexpected decorations");
return false;
}
bool ParserImpl::match(Token::Type tok, Source* source /*= nullptr*/) {
auto t = peek();
if (source != nullptr)
*source = t.source();
if (t.Is(tok)) {
next();
return true;
}
return false;
}
bool ParserImpl::expect(const std::string& use, Token::Type tok) {
auto t = peek();
if (t.Is(tok)) {
next();
synchronized_ = true;
return true;
}
// Special case to split `>>` and `>=` tokens if we are looking for a `>`.
if (tok == Token::Type::kGreaterThan &&
(t.IsShiftRight() || t.IsGreaterThanEqual())) {
next();
// Push the second character to the token queue.
auto source = t.source();
source.range.begin.column++;
if (t.IsShiftRight())
token_queue_.push_front(Token(Token::Type::kGreaterThan, source));
else if (t.IsGreaterThanEqual())
token_queue_.push_front(Token(Token::Type::kEqual, source));
synchronized_ = true;
return true;
}
// Handle the case when `]` is expected but the actual token is `]]`.
// For example, in `arr1[arr2[0]]`.
if (tok == Token::Type::kBracketRight && t.IsAttrRight()) {
next();
auto source = t.source();
source.range.begin.column++;
token_queue_.push_front({Token::Type::kBracketRight, source});
synchronized_ = true;
return true;
}
std::stringstream err;
err << "expected '" << Token::TypeToName(tok) << "'";
if (!use.empty()) {
err << " for " << use;
}
add_error(t, err.str());
synchronized_ = false;
return false;
}
Expect<int32_t> ParserImpl::expect_sint(const std::string& use) {
auto t = peek();
if (!t.IsSintLiteral())
return add_error(t.source(), "expected signed integer literal", use);
next();
return {t.to_i32(), t.source()};
}
Expect<uint32_t> ParserImpl::expect_positive_sint(const std::string& use) {
auto sint = expect_sint(use);
if (sint.errored)
return Failure::kErrored;
if (sint.value < 0)
return add_error(sint.source, use + " must be positive");
return {static_cast<uint32_t>(sint.value), sint.source};
}
Expect<uint32_t> ParserImpl::expect_nonzero_positive_sint(
const std::string& use) {
auto sint = expect_sint(use);
if (sint.errored)
return Failure::kErrored;
if (sint.value <= 0)
return add_error(sint.source, use + " must be greater than 0");
return {static_cast<uint32_t>(sint.value), sint.source};
}
Expect<std::string> ParserImpl::expect_ident(const std::string& use) {
auto t = peek();
if (t.IsIdentifier()) {
synchronized_ = true;
next();
return {t.to_str(), t.source()};
}
synchronized_ = false;
return add_error(t.source(), "expected identifier", use);
}
template <typename F, typename T>
T ParserImpl::expect_block(Token::Type start,
Token::Type end,
const std::string& use,
F&& body) {
if (!expect(use, start)) {
return Failure::kErrored;
}
return sync(end, [&]() -> T {
auto res = body();
if (res.errored)
return Failure::kErrored;
if (!expect(use, end))
return Failure::kErrored;
return res;
});
}
template <typename F, typename T>
T ParserImpl::expect_paren_block(const std::string& use, F&& body) {
return expect_block(Token::Type::kParenLeft, Token::Type::kParenRight, use,
std::forward<F>(body));
}
template <typename F, typename T>
T ParserImpl::expect_brace_block(const std::string& use, F&& body) {
return expect_block(Token::Type::kBraceLeft, Token::Type::kBraceRight, use,
std::forward<F>(body));
}
template <typename F, typename T>
T ParserImpl::expect_lt_gt_block(const std::string& use, F&& body) {
return expect_block(Token::Type::kLessThan, Token::Type::kGreaterThan, use,
std::forward<F>(body));
}
template <typename F, typename T>
T ParserImpl::sync(Token::Type tok, F&& body) {
if (sync_depth_ >= kMaxSyncDepth) {
// We've hit a maximum parser recursive depth.
// We can't call into body() as we might stack overflow.
// Instead, report an error...
add_error(peek(), "maximum parser recursive depth reached");
// ...and try to resynchronize. If we cannot resynchronize to `tok` then
// synchronized_ is set to false, and the parser knows that forward progress
// is not being made.
sync_to(tok, /* consume: */ true);
return Failure::kErrored;
}
sync_tokens_.push_back(tok);
++sync_depth_;
auto result = body();
--sync_depth_;
assert(sync_tokens_.back() == tok);
sync_tokens_.pop_back();
if (result.errored) {
sync_to(tok, /* consume: */ true);
}
return result;
}
bool ParserImpl::sync_to(Token::Type tok, bool consume) {
// Clear the synchronized state - gets set to true again on success.
synchronized_ = false;
BlockCounters counters;
for (size_t i = 0; i < kMaxResynchronizeLookahead; i++) {
auto t = peek(i);
if (counters.consume(t) > 0)
continue; // Nested block
if (!t.Is(tok) && !is_sync_token(t))
continue; // Not a synchronization point
// Synchronization point found.
// Skip any tokens we don't understand, bringing us to just before the
// resync point.
while (i-- > 0) {
next();
}
// Is this synchronization token |tok|?
if (t.Is(tok)) {
if (consume)
next();
synchronized_ = true;
return true;
}
break;
}
return false;
}
bool ParserImpl::is_sync_token(const Token& t) const {
for (auto r : sync_tokens_) {
if (t.Is(r))
return true;
}
return false;
}
template <typename F, typename T>
T ParserImpl::without_error(F&& body) {
silence_errors_++;
auto result = body();
silence_errors_--;
return result;
}
} // namespace wgsl
} // namespace reader
} // namespace tint