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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/resolver/resolver.h"
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <utility>
#include "src/ast/alias.h"
#include "src/ast/array.h"
#include "src/ast/assignment_statement.h"
#include "src/ast/bitcast_expression.h"
#include "src/ast/break_statement.h"
#include "src/ast/call_statement.h"
#include "src/ast/continue_statement.h"
#include "src/ast/depth_texture.h"
#include "src/ast/disable_validation_decoration.h"
#include "src/ast/discard_statement.h"
#include "src/ast/fallthrough_statement.h"
#include "src/ast/for_loop_statement.h"
#include "src/ast/if_statement.h"
#include "src/ast/internal_decoration.h"
#include "src/ast/interpolate_decoration.h"
#include "src/ast/loop_statement.h"
#include "src/ast/matrix.h"
#include "src/ast/override_decoration.h"
#include "src/ast/pointer.h"
#include "src/ast/return_statement.h"
#include "src/ast/sampled_texture.h"
#include "src/ast/sampler.h"
#include "src/ast/storage_texture.h"
#include "src/ast/struct_block_decoration.h"
#include "src/ast/switch_statement.h"
#include "src/ast/type_name.h"
#include "src/ast/unary_op_expression.h"
#include "src/ast/variable_decl_statement.h"
#include "src/ast/vector.h"
#include "src/ast/workgroup_decoration.h"
#include "src/sem/array.h"
#include "src/sem/atomic_type.h"
#include "src/sem/call.h"
#include "src/sem/depth_multisampled_texture_type.h"
#include "src/sem/depth_texture_type.h"
#include "src/sem/for_loop_statement.h"
#include "src/sem/function.h"
#include "src/sem/if_statement.h"
#include "src/sem/loop_statement.h"
#include "src/sem/member_accessor_expression.h"
#include "src/sem/multisampled_texture_type.h"
#include "src/sem/pointer_type.h"
#include "src/sem/reference_type.h"
#include "src/sem/sampled_texture_type.h"
#include "src/sem/sampler_type.h"
#include "src/sem/statement.h"
#include "src/sem/storage_texture_type.h"
#include "src/sem/struct.h"
#include "src/sem/switch_statement.h"
#include "src/sem/variable.h"
#include "src/utils/defer.h"
#include "src/utils/get_or_create.h"
#include "src/utils/math.h"
#include "src/utils/scoped_assignment.h"
namespace tint {
namespace resolver {
namespace {
using IntrinsicType = tint::sem::IntrinsicType;
bool IsValidStorageTextureDimension(ast::TextureDimension dim) {
switch (dim) {
case ast::TextureDimension::k1d:
case ast::TextureDimension::k2d:
case ast::TextureDimension::k2dArray:
case ast::TextureDimension::k3d:
return true;
default:
return false;
}
}
bool IsValidStorageTextureImageFormat(ast::ImageFormat format) {
switch (format) {
case ast::ImageFormat::kR32Uint:
case ast::ImageFormat::kR32Sint:
case ast::ImageFormat::kR32Float:
case ast::ImageFormat::kRg32Uint:
case ast::ImageFormat::kRg32Sint:
case ast::ImageFormat::kRg32Float:
case ast::ImageFormat::kRgba8Unorm:
case ast::ImageFormat::kRgba8Snorm:
case ast::ImageFormat::kRgba8Uint:
case ast::ImageFormat::kRgba8Sint:
case ast::ImageFormat::kRgba16Uint:
case ast::ImageFormat::kRgba16Sint:
case ast::ImageFormat::kRgba16Float:
case ast::ImageFormat::kRgba32Uint:
case ast::ImageFormat::kRgba32Sint:
case ast::ImageFormat::kRgba32Float:
return true;
default:
return false;
}
}
/// @returns true if the decoration list contains a
/// ast::DisableValidationDecoration with the validation mode equal to
/// `validation`
bool IsValidationDisabled(const ast::DecorationList& decorations,
ast::DisabledValidation validation) {
for (auto* decoration : decorations) {
if (auto* dv = decoration->As<ast::DisableValidationDecoration>()) {
if (dv->Validation() == validation) {
return true;
}
}
}
return false;
}
/// @returns true if the decoration list does not contains a
/// ast::DisableValidationDecoration with the validation mode equal to
/// `validation`
bool IsValidationEnabled(const ast::DecorationList& decorations,
ast::DisabledValidation validation) {
return !IsValidationDisabled(decorations, validation);
}
// Helper to stringify a pipeline IO decoration.
std::string deco_to_str(const ast::Decoration* deco) {
std::stringstream str;
if (auto* builtin = deco->As<ast::BuiltinDecoration>()) {
str << "builtin(" << builtin->value() << ")";
} else if (auto* location = deco->As<ast::LocationDecoration>()) {
str << "location(" << location->value() << ")";
}
return str.str();
}
} // namespace
Resolver::Resolver(ProgramBuilder* builder)
: builder_(builder),
diagnostics_(builder->Diagnostics()),
intrinsic_table_(IntrinsicTable::Create(*builder)) {}
Resolver::~Resolver() = default;
void Resolver::set_referenced_from_function_if_needed(VariableInfo* var,
bool local) {
if (current_function_ == nullptr) {
return;
}
if (var->kind != VariableKind::kGlobal) {
return;
}
current_function_->referenced_module_vars.add(var);
if (local) {
current_function_->local_referenced_module_vars.add(var);
}
}
bool Resolver::Resolve() {
if (builder_->Diagnostics().contains_errors()) {
return false;
}
bool result = ResolveInternal();
if (!result && !diagnostics_.contains_errors()) {
TINT_ICE(Resolver, diagnostics_)
<< "resolving failed, but no error was raised";
return false;
}
// Even if resolving failed, create all the semantic nodes for information we
// did generate.
CreateSemanticNodes();
return result;
}
// https://gpuweb.github.io/gpuweb/wgsl/#plain-types-section
bool Resolver::IsPlain(const sem::Type* type) const {
return type->is_scalar() || type->Is<sem::Atomic>() ||
type->Is<sem::Vector>() || type->Is<sem::Matrix>() ||
type->Is<sem::Array>() || type->Is<sem::Struct>();
}
// https://gpuweb.github.io/gpuweb/wgsl.html#storable-types
bool Resolver::IsStorable(const sem::Type* type) const {
return IsPlain(type) || type->Is<sem::Texture>() || type->Is<sem::Sampler>();
}
// https://gpuweb.github.io/gpuweb/wgsl.html#host-shareable-types
bool Resolver::IsHostShareable(const sem::Type* type) const {
if (type->IsAnyOf<sem::I32, sem::U32, sem::F32>()) {
return true;
}
if (auto* vec = type->As<sem::Vector>()) {
return IsHostShareable(vec->type());
}
if (auto* mat = type->As<sem::Matrix>()) {
return IsHostShareable(mat->type());
}
if (auto* arr = type->As<sem::Array>()) {
return IsHostShareable(arr->ElemType());
}
if (auto* str = type->As<sem::Struct>()) {
for (auto* member : str->Members()) {
if (!IsHostShareable(member->Type())) {
return false;
}
}
return true;
}
if (auto* atomic = type->As<sem::Atomic>()) {
return IsHostShareable(atomic->Type());
}
return false;
}
bool Resolver::ResolveInternal() {
Mark(&builder_->AST());
// Process everything else in the order they appear in the module. This is
// necessary for validation of use-before-declaration.
for (auto* decl : builder_->AST().GlobalDeclarations()) {
if (auto* td = decl->As<ast::TypeDecl>()) {
Mark(td);
if (!TypeDecl(td)) {
return false;
}
} else if (auto* func = decl->As<ast::Function>()) {
Mark(func);
if (!Function(func)) {
return false;
}
} else if (auto* var = decl->As<ast::Variable>()) {
Mark(var);
if (!GlobalVariable(var)) {
return false;
}
} else {
TINT_UNREACHABLE(Resolver, diagnostics_)
<< "unhandled global declaration: " << decl->TypeInfo().name;
return false;
}
}
if (!ValidatePipelineStages()) {
return false;
}
bool result = true;
for (auto* node : builder_->ASTNodes().Objects()) {
if (marked_.count(node) == 0) {
TINT_ICE(Resolver, diagnostics_)
<< "AST node '" << node->TypeInfo().name
<< "' was not reached by the resolver\n"
<< "At: " << node->source() << "\n"
<< "Content: " << builder_->str(node) << "\n"
<< "Pointer: " << node;
result = false;
}
}
return result;
}
sem::Type* Resolver::Type(const ast::Type* ty) {
Mark(ty);
auto* s = [&]() -> sem::Type* {
if (ty->Is<ast::Void>()) {
return builder_->create<sem::Void>();
}
if (ty->Is<ast::Bool>()) {
return builder_->create<sem::Bool>();
}
if (ty->Is<ast::I32>()) {
return builder_->create<sem::I32>();
}
if (ty->Is<ast::U32>()) {
return builder_->create<sem::U32>();
}
if (ty->Is<ast::F32>()) {
return builder_->create<sem::F32>();
}
if (auto* t = ty->As<ast::Vector>()) {
if (auto* el = Type(t->type())) {
if (auto* vector = builder_->create<sem::Vector>(
const_cast<sem::Type*>(el), t->size())) {
if (ValidateVector(vector, t->source())) {
return vector;
}
}
}
return nullptr;
}
if (auto* t = ty->As<ast::Matrix>()) {
if (auto* el = Type(t->type())) {
if (auto* column_type = builder_->create<sem::Vector>(
const_cast<sem::Type*>(el), t->rows())) {
if (auto* matrix =
builder_->create<sem::Matrix>(column_type, t->columns())) {
if (ValidateMatrix(matrix, t->source())) {
return matrix;
}
}
}
}
return nullptr;
}
if (auto* t = ty->As<ast::Array>()) {
return Array(t);
}
if (auto* t = ty->As<ast::Atomic>()) {
if (auto* el = Type(t->type())) {
auto* a = builder_->create<sem::Atomic>(const_cast<sem::Type*>(el));
if (!ValidateAtomic(t, a)) {
return nullptr;
}
return a;
}
return nullptr;
}
if (auto* t = ty->As<ast::Pointer>()) {
if (auto* el = Type(t->type())) {
auto access = t->access();
if (access == ast::kUndefined) {
access = DefaultAccessForStorageClass(t->storage_class());
}
return builder_->create<sem::Pointer>(const_cast<sem::Type*>(el),
t->storage_class(), access);
}
return nullptr;
}
if (auto* t = ty->As<ast::Sampler>()) {
return builder_->create<sem::Sampler>(t->kind());
}
if (auto* t = ty->As<ast::SampledTexture>()) {
if (auto* el = Type(t->type())) {
return builder_->create<sem::SampledTexture>(
t->dim(), const_cast<sem::Type*>(el));
}
return nullptr;
}
if (auto* t = ty->As<ast::MultisampledTexture>()) {
if (auto* el = Type(t->type())) {
return builder_->create<sem::MultisampledTexture>(
t->dim(), const_cast<sem::Type*>(el));
}
return nullptr;
}
if (auto* t = ty->As<ast::DepthTexture>()) {
return builder_->create<sem::DepthTexture>(t->dim());
}
if (auto* t = ty->As<ast::DepthMultisampledTexture>()) {
return builder_->create<sem::DepthMultisampledTexture>(t->dim());
}
if (auto* t = ty->As<ast::StorageTexture>()) {
if (auto* el = Type(t->type())) {
if (!ValidateStorageTexture(t)) {
return nullptr;
}
return builder_->create<sem::StorageTexture>(
t->dim(), t->image_format(), t->access(),
const_cast<sem::Type*>(el));
}
return nullptr;
}
if (ty->As<ast::ExternalTexture>()) {
return builder_->create<sem::ExternalTexture>();
}
if (auto* t = ty->As<ast::TypeName>()) {
auto it = named_type_info_.find(t->name());
if (it == named_type_info_.end()) {
AddError(
"unknown type '" + builder_->Symbols().NameFor(t->name()) + "'",
t->source());
return nullptr;
}
return it->second.sem;
}
TINT_UNREACHABLE(Resolver, diagnostics_)
<< "Unhandled ast::Type: " << ty->TypeInfo().name;
return nullptr;
}();
if (s) {
builder_->Sem().Add(ty, s);
}
return s;
}
bool Resolver::ValidateAtomic(const ast::Atomic* a, const sem::Atomic* s) {
// https://gpuweb.github.io/gpuweb/wgsl/#atomic-types
// T must be either u32 or i32.
if (!s->Type()->IsAnyOf<sem::U32, sem::I32>()) {
AddError("atomic only supports i32 or u32 types",
a->type() ? a->type()->source() : a->source());
return false;
}
return true;
}
bool Resolver::ValidateStorageTexture(const ast::StorageTexture* t) {
switch (t->access()) {
case ast::Access::kUndefined:
AddError("storage textures must have access control", t->source());
return false;
case ast::Access::kReadWrite:
AddError("storage textures only support read-only and write-only access",
t->source());
return false;
case ast::Access::kRead:
case ast::Access::kWrite:
break;
}
if (!IsValidStorageTextureDimension(t->dim())) {
AddError("cube dimensions for storage textures are not supported",
t->source());
return false;
}
if (!IsValidStorageTextureImageFormat(t->image_format())) {
AddError(
"image format must be one of the texel formats specified for storage "
"textues in https://gpuweb.github.io/gpuweb/wgsl/#texel-formats",
t->source());
return false;
}
return true;
}
Resolver::VariableInfo* Resolver::Variable(ast::Variable* var,
VariableKind kind,
uint32_t index /* = 0 */) {
if (variable_to_info_.count(var)) {
TINT_ICE(Resolver, diagnostics_)
<< "Variable " << builder_->Symbols().NameFor(var->symbol())
<< " already resolved";
return nullptr;
}
std::string type_name;
const sem::Type* storage_type = nullptr;
// If the variable has a declared type, resolve it.
if (auto* ty = var->type()) {
type_name = ty->FriendlyName(builder_->Symbols());
storage_type = Type(ty);
if (!storage_type) {
return nullptr;
}
}
std::string rhs_type_name;
const sem::Type* rhs_type = nullptr;
// Does the variable have a constructor?
if (auto* ctor = var->constructor()) {
Mark(var->constructor());
if (!Expression(var->constructor())) {
return nullptr;
}
// Fetch the constructor's type
rhs_type_name = TypeNameOf(ctor);
rhs_type = TypeOf(ctor);
if (!rhs_type) {
return nullptr;
}
// If the variable has no declared type, infer it from the RHS
if (!storage_type) {
if (!var->is_const() && kind == VariableKind::kGlobal) {
AddError("global var declaration must specify a type", var->source());
return nullptr;
}
type_name = rhs_type_name;
storage_type = rhs_type->UnwrapRef(); // Implicit load of RHS
}
} else if (var->is_const() && kind != VariableKind::kParameter &&
!ast::HasDecoration<ast::OverrideDecoration>(var->decorations())) {
AddError("let declaration must have an initializer", var->source());
return nullptr;
} else if (!var->type()) {
AddError(
(kind == VariableKind::kGlobal)
? "module scope var declaration requires a type and initializer"
: "function scope var declaration requires a type or initializer",
var->source());
return nullptr;
}
if (!storage_type) {
TINT_ICE(Resolver, diagnostics_)
<< "failed to determine storage type for variable '" +
builder_->Symbols().NameFor(var->symbol()) + "'\n"
<< "Source: " << var->source();
return nullptr;
}
auto storage_class = var->declared_storage_class();
if (storage_class == ast::StorageClass::kNone) {
if (storage_type->UnwrapRef()->is_handle()) {
// https://gpuweb.github.io/gpuweb/wgsl/#module-scope-variables
// If the store type is a texture type or a sampler type, then the
// variable declaration must not have a storage class decoration. The
// storage class will always be handle.
storage_class = ast::StorageClass::kUniformConstant;
} else if (kind == VariableKind::kLocal && !var->is_const()) {
storage_class = ast::StorageClass::kFunction;
}
}
auto access = var->declared_access();
if (access == ast::Access::kUndefined) {
access = DefaultAccessForStorageClass(storage_class);
}
auto* type = storage_type;
if (!var->is_const()) {
// Variable declaration. Unlike `let`, `var` has storage.
// Variables are always of a reference type to the declared storage type.
type =
builder_->create<sem::Reference>(storage_type, storage_class, access);
}
if (rhs_type && !ValidateVariableConstructor(var, storage_type, type_name,
rhs_type, rhs_type_name)) {
return nullptr;
}
auto* info =
variable_infos_.Create(var, const_cast<sem::Type*>(type), type_name,
storage_class, access, kind, index);
variable_to_info_.emplace(var, info);
return info;
}
ast::Access Resolver::DefaultAccessForStorageClass(
ast::StorageClass storage_class) {
// https://gpuweb.github.io/gpuweb/wgsl/#storage-class
switch (storage_class) {
case ast::StorageClass::kStorage:
case ast::StorageClass::kUniform:
case ast::StorageClass::kUniformConstant:
return ast::Access::kRead;
default:
break;
}
return ast::Access::kReadWrite;
}
bool Resolver::ValidateVariableConstructor(const ast::Variable* var,
const sem::Type* storage_type,
const std::string& type_name,
const sem::Type* rhs_type,
const std::string& rhs_type_name) {
auto* value_type = rhs_type->UnwrapRef(); // Implicit load of RHS
// Value type has to match storage type
if (storage_type != value_type) {
std::string decl = var->is_const() ? "let" : "var";
AddError("cannot initialize " + decl + " of type '" + type_name +
"' with value of type '" + rhs_type_name + "'",
var->source());
return false;
}
return true;
}
bool Resolver::GlobalVariable(ast::Variable* var) {
if (!ValidateNoDuplicateDefinition(var->symbol(), var->source(),
/* check_global_scope_only */ true)) {
return false;
}
auto* info = Variable(var, VariableKind::kGlobal);
if (!info) {
return false;
}
variable_stack_.set_global(var->symbol(), info);
if (!var->is_const() && info->storage_class == ast::StorageClass::kNone) {
AddError("global variables must have a storage class", var->source());
return false;
}
if (var->is_const() && !(info->storage_class == ast::StorageClass::kNone)) {
AddError("global constants shouldn't have a storage class", var->source());
return false;
}
for (auto* deco : var->decorations()) {
Mark(deco);
if (auto* override_deco = deco->As<ast::OverrideDecoration>()) {
// Track the constant IDs that are specified in the shader.
if (override_deco->HasValue()) {
constant_ids_.emplace(override_deco->value(), info);
}
}
}
if (!ValidateNoDuplicateDecorations(var->decorations())) {
return false;
}
if (auto bp = var->binding_point()) {
info->binding_point = {bp.group->value(), bp.binding->value()};
}
if (!ValidateGlobalVariable(info)) {
return false;
}
if (!ApplyStorageClassUsageToType(
info->storage_class, const_cast<sem::Type*>(info->type->UnwrapRef()),
var->source())) {
AddNote("while instantiating variable " +
builder_->Symbols().NameFor(var->symbol()),
var->source());
return false;
}
// TODO(bclayton): Call this at the end of resolve on all uniform and storage
// referenced structs
if (!ValidateStorageClassLayout(info)) {
return false;
}
return true;
}
bool Resolver::ValidateStorageClassLayout(const sem::Struct* str,
ast::StorageClass sc) {
// https://gpuweb.github.io/gpuweb/wgsl/#storage-class-layout-constraints
auto is_uniform_struct_or_array = [sc](const sem::Type* ty) {
return sc == ast::StorageClass::kUniform &&
ty->IsAnyOf<sem::Array, sem::Struct>();
};
auto is_uniform_struct = [sc](const sem::Type* ty) {
return sc == ast::StorageClass::kUniform && ty->Is<sem::Struct>();
};
auto required_alignment_of = [&](const sem::Type* ty) {
uint32_t actual_align = ty->Align();
uint32_t required_align = actual_align;
if (is_uniform_struct_or_array(ty)) {
required_align = utils::RoundUp(16u, actual_align);
}
return required_align;
};
auto member_name_of = [this](const sem::StructMember* sm) {
return builder_->Symbols().NameFor(sm->Declaration()->symbol());
};
auto type_name_of = [this](const sem::StructMember* sm) {
return sm->Declaration()->type()->FriendlyName(builder_->Symbols());
};
// TODO(amaiorano): Output struct and member decorations so that this output
// can be copied verbatim back into source
auto get_struct_layout_string = [&](const sem::Struct* st) -> std::string {
std::stringstream ss;
if (st->Members().empty()) {
TINT_ICE(Resolver, diagnostics_) << "Validation should have ensured that "
"structs have at least one member";
return {};
}
const auto* const last_member = st->Members().back();
const uint32_t last_member_struct_padding_offset =
last_member->Offset() + last_member->Size();
// Compute max widths to align output
const auto offset_w =
static_cast<int>(::log10(last_member_struct_padding_offset)) + 1;
const auto size_w = static_cast<int>(::log10(st->Size())) + 1;
const auto align_w = static_cast<int>(::log10(st->Align())) + 1;
auto print_struct_begin_line = [&](size_t align, size_t size,
std::string struct_name) {
ss << "/* " << std::setw(offset_w) << " "
<< "align(" << std::setw(align_w) << align << ") size("
<< std::setw(size_w) << size << ") */ struct " << struct_name
<< " {\n";
};
auto print_struct_end_line = [&]() {
ss << "/* "
<< std::setw(offset_w + size_w + align_w) << " "
<< "*/ };";
};
auto print_member_line = [&](size_t offset, size_t align, size_t size,
std::string s) {
ss << "/* offset(" << std::setw(offset_w) << offset << ") align("
<< std::setw(align_w) << align << ") size(" << std::setw(size_w)
<< size << ") */ " << s << ";\n";
};
print_struct_begin_line(st->Align(), st->Size(),
st->FriendlyName(builder_->Symbols()));
for (size_t i = 0; i < st->Members().size(); ++i) {
auto* const m = st->Members()[i];
// Output field alignment padding, if any
auto* const prev_member = (i == 0) ? nullptr : str->Members()[i - 1];
if (prev_member) {
uint32_t padding =
m->Offset() - (prev_member->Offset() + prev_member->Size());
if (padding > 0) {
size_t padding_offset = m->Offset() - padding;
print_member_line(padding_offset, 1, padding,
"// -- implicit field alignment padding --");
}
}
// Output member
std::string member_name = member_name_of(m);
print_member_line(m->Offset(), m->Align(), m->Size(),
member_name_of(m) + " : " + type_name_of(m));
}
// Output struct size padding, if any
uint32_t struct_padding = st->Size() - last_member_struct_padding_offset;
if (struct_padding > 0) {
print_member_line(last_member_struct_padding_offset, 1, struct_padding,
"// -- implicit struct size padding --");
}
print_struct_end_line();
return ss.str();
};
if (!ast::IsHostShareable(sc)) {
return true;
}
for (size_t i = 0; i < str->Members().size(); ++i) {
auto* const m = str->Members()[i];
uint32_t required_align = required_alignment_of(m->Type());
// Validate that member is at a valid byte offset
if (m->Offset() % required_align != 0) {
AddError("the offset of a struct member of type '" + type_name_of(m) +
"' in storage class '" + ast::str(sc) +
"' must be a multiple of " + std::to_string(required_align) +
" bytes, but '" + member_name_of(m) +
"' is currently at offset " + std::to_string(m->Offset()) +
". Consider setting [[align(" +
std::to_string(required_align) + ")]] on this member",
m->Declaration()->source());
AddNote("see layout of struct:\n" + get_struct_layout_string(str),
str->Declaration()->source());
if (auto* member_str = m->Type()->As<sem::Struct>()) {
AddNote("and layout of struct member:\n" +
get_struct_layout_string(member_str),
member_str->Declaration()->source());
}
return false;
}
// For uniform buffers, validate that the number of bytes between the
// previous member of type struct and the current is a multiple of 16 bytes.
auto* const prev_member = (i == 0) ? nullptr : str->Members()[i - 1];
if (prev_member && is_uniform_struct(prev_member->Type())) {
const uint32_t prev_to_curr_offset = m->Offset() - prev_member->Offset();
if (prev_to_curr_offset % 16 != 0) {
AddError(
"uniform storage requires that the number of bytes between the "
"start of the previous member of type struct and the current "
"member be a multiple of 16 bytes, but there are currently " +
std::to_string(prev_to_curr_offset) + " bytes between '" +
member_name_of(prev_member) + "' and '" + member_name_of(m) +
"'. Consider setting [[align(16)]] on this member",
m->Declaration()->source());
AddNote("see layout of struct:\n" + get_struct_layout_string(str),
str->Declaration()->source());
auto* prev_member_str = prev_member->Type()->As<sem::Struct>();
AddNote("and layout of previous member struct:\n" +
get_struct_layout_string(prev_member_str),
prev_member_str->Declaration()->source());
return false;
}
}
// For uniform buffer array members, validate that array elements are
// aligned to 16 bytes
if (auto* arr = m->Type()->As<sem::Array>()) {
if (sc == ast::StorageClass::kUniform) {
// We already validated that this array member is itself aligned to 16
// bytes above, so we only need to validate that stride is a multiple of
// 16 bytes.
if (arr->Stride() % 16 != 0) {
AddError(
"uniform storage requires that array elements be aligned to 16 "
"bytes, but array stride of '" +
member_name_of(m) + "' is currently " +
std::to_string(arr->Stride()) +
". Consider setting [[stride(" +
std::to_string(
utils::RoundUp(required_align, arr->Stride())) +
")]] on the array type",
m->Declaration()->type()->source());
AddNote("see layout of struct:\n" + get_struct_layout_string(str),
str->Declaration()->source());
return false;
}
}
}
// If member is struct, recurse
if (auto* str_member = m->Type()->As<sem::Struct>()) {
// Cache result of struct + storage class pair
if (valid_struct_storage_layouts_.emplace(str_member, sc).second) {
if (!ValidateStorageClassLayout(str_member, sc)) {
return false;
}
}
}
}
return true;
}
bool Resolver::ValidateStorageClassLayout(const VariableInfo* info) {
if (auto* str = info->type->UnwrapRef()->As<sem::Struct>()) {
if (!ValidateStorageClassLayout(str, info->storage_class)) {
AddNote("see declaration of variable", info->declaration->source());
return false;
}
}
return true;
}
bool Resolver::ValidateGlobalVariable(const VariableInfo* info) {
if (!ValidateNoDuplicateDecorations(info->declaration->decorations())) {
return false;
}
for (auto* deco : info->declaration->decorations()) {
if (info->declaration->is_const()) {
if (auto* override_deco = deco->As<ast::OverrideDecoration>()) {
if (override_deco->HasValue()) {
uint32_t id = override_deco->value();
auto itr = constant_ids_.find(id);
if (itr != constant_ids_.end() && itr->second != info) {
AddError("pipeline constant IDs must be unique", deco->source());
AddNote("a pipeline constant with an ID of " + std::to_string(id) +
" was previously declared "
"here:",
ast::GetDecoration<ast::OverrideDecoration>(
itr->second->declaration->decorations())
->source());
return false;
}
if (id > 65535) {
AddError("pipeline constant IDs must be between 0 and 65535",
deco->source());
return false;
}
}
} else {
AddError("decoration is not valid for constants", deco->source());
return false;
}
} else {
bool is_shader_io_decoration =
deco->IsAnyOf<ast::BuiltinDecoration, ast::InterpolateDecoration,
ast::InvariantDecoration, ast::LocationDecoration>();
bool has_io_storage_class =
info->storage_class == ast::StorageClass::kInput ||
info->storage_class == ast::StorageClass::kOutput;
if (!(deco->IsAnyOf<ast::BindingDecoration, ast::GroupDecoration,
ast::InternalDecoration>()) &&
(!is_shader_io_decoration || !has_io_storage_class)) {
AddError("decoration is not valid for variables", deco->source());
return false;
}
}
}
auto binding_point = info->declaration->binding_point();
switch (info->storage_class) {
case ast::StorageClass::kUniform:
case ast::StorageClass::kStorage:
case ast::StorageClass::kUniformConstant: {
// https://gpuweb.github.io/gpuweb/wgsl/#resource-interface
// Each resource variable must be declared with both group and binding
// attributes.
if (!binding_point) {
AddError(
"resource variables require [[group]] and [[binding]] "
"decorations",
info->declaration->source());
return false;
}
break;
}
default:
if (binding_point.binding || binding_point.group) {
// https://gpuweb.github.io/gpuweb/wgsl/#attribute-binding
// Must only be applied to a resource variable
AddError(
"non-resource variables must not have [[group]] or [[binding]] "
"decorations",
info->declaration->source());
return false;
}
}
// https://gpuweb.github.io/gpuweb/wgsl/#variable-declaration
// The access mode always has a default, and except for variables in the
// storage storage class, must not be written.
if (info->storage_class != ast::StorageClass::kStorage &&
info->declaration->declared_access() != ast::Access::kUndefined) {
AddError(
"only variables in <storage> storage class may declare an access mode",
info->declaration->source());
return false;
}
switch (info->storage_class) {
case ast::StorageClass::kStorage: {
// https://gpuweb.github.io/gpuweb/wgsl/#module-scope-variables
// A variable in the storage storage class is a storage buffer variable.
// Its store type must be a host-shareable structure type with block
// attribute, satisfying the storage class constraints.
auto* str = info->type->UnwrapRef()->As<sem::Struct>();
if (!str) {
AddError(
"variables declared in the <storage> storage class must be of a "
"structure type",
info->declaration->source());
return false;
}
if (!str->IsBlockDecorated()) {
AddError(
"structure used as a storage buffer must be declared with the "
"[[block]] decoration",
str->Declaration()->source());
if (info->declaration->source().range.begin.line) {
AddNote("structure used as storage buffer here",
info->declaration->source());
}
return false;
}
break;
}
case ast::StorageClass::kUniform: {
// https://gpuweb.github.io/gpuweb/wgsl/#module-scope-variables
// A variable in the uniform storage class is a uniform buffer variable.
// Its store type must be a host-shareable structure type with block
// attribute, satisfying the storage class constraints.
auto* str = info->type->UnwrapRef()->As<sem::Struct>();
if (!str) {
AddError(
"variables declared in the <uniform> storage class must be of a "
"structure type",
info->declaration->source());
return false;
}
if (!str->IsBlockDecorated()) {
AddError(
"structure used as a uniform buffer must be declared with the "
"[[block]] decoration",
str->Declaration()->source());
if (info->declaration->source().range.begin.line) {
AddNote("structure used as uniform buffer here",
info->declaration->source());
}
return false;
}
for (auto* member : str->Members()) {
if (auto* arr = member->Type()->As<sem::Array>()) {
if (arr->IsRuntimeSized()) {
AddError(
"structure containing a runtime sized array "
"cannot be used as a uniform buffer",
info->declaration->source());
AddNote("structure is declared here", str->Declaration()->source());
return false;
}
}
}
break;
}
default:
break;
}
if (!info->declaration->is_const()) {
if (!ValidateAtomicVariable(info)) {
return false;
}
}
return ValidateVariable(info);
}
// https://gpuweb.github.io/gpuweb/wgsl/#atomic-types
// Atomic types may only be instantiated by variables in the workgroup storage
// class or by storage buffer variables with a read_write access mode.
bool Resolver::ValidateAtomicVariable(const VariableInfo* info) {
auto sc = info->storage_class;
auto access = info->access;
auto* type = info->type->UnwrapRef();
auto source = info->declaration->type() ? info->declaration->type()->source()
: info->declaration->source();
if (type->Is<sem::Atomic>()) {
if (sc != ast::StorageClass::kWorkgroup) {
AddError(
"atomic variables must have <storage> or <workgroup> storage class",
source);
return false;
}
} else if (type->IsAnyOf<sem::Struct, sem::Array>()) {
auto found = atomic_composite_info_.find(type);
if (found != atomic_composite_info_.end()) {
if (sc != ast::StorageClass::kStorage &&
sc != ast::StorageClass::kWorkgroup) {
AddError(
"atomic variables must have <storage> or <workgroup> storage class",
source);
AddNote("atomic sub-type of '" +
type->FriendlyName(builder_->Symbols()) +
"' is declared here",
found->second);
return false;
} else if (sc == ast::StorageClass::kStorage &&
access != ast::Access::kReadWrite) {
AddError(
"atomic variables in <storage> storage class must have read_write "
"access mode",
source);
AddNote("atomic sub-type of '" +
type->FriendlyName(builder_->Symbols()) +
"' is declared here",
found->second);
return false;
}
}
}
return true;
}
bool Resolver::ValidateVariable(const VariableInfo* info) {
auto* var = info->declaration;
auto* storage_type = info->type->UnwrapRef();
if (!var->is_const() && !IsStorable(storage_type)) {
AddError(storage_type->FriendlyName(builder_->Symbols()) +
" cannot be used as the type of a var",
var->source());
return false;
}
if (var->is_const() && info->kind != VariableKind::kParameter &&
!(storage_type->IsConstructible() || storage_type->Is<sem::Pointer>())) {
AddError(storage_type->FriendlyName(builder_->Symbols()) +
" cannot be used as the type of a let",
var->source());
return false;
}
if (auto* r = storage_type->As<sem::Array>()) {
if (r->IsRuntimeSized()) {
AddError("runtime arrays may only appear as the last member of a struct",
var->source());
return false;
}
}
if (auto* r = storage_type->As<sem::MultisampledTexture>()) {
if (r->dim() != ast::TextureDimension::k2d) {
AddError("only 2d multisampled textures are supported", var->source());
return false;
}
if (!r->type()->UnwrapRef()->is_numeric_scalar()) {
AddError("texture_multisampled_2d<type>: type must be f32, i32 or u32",
var->source());
return false;
}
}
if (storage_type->is_handle() &&
var->declared_storage_class() != ast::StorageClass::kNone) {
// https://gpuweb.github.io/gpuweb/wgsl/#module-scope-variables
// If the store type is a texture type or a sampler type, then the
// variable declaration must not have a storage class decoration. The
// storage class will always be handle.
AddError("variables of type '" + info->type_name +
"' must not have a storage class",
var->source());
return false;
}
if (IsValidationEnabled(var->decorations(),
ast::DisabledValidation::kIgnoreStorageClass) &&
(var->declared_storage_class() == ast::StorageClass::kInput ||
var->declared_storage_class() == ast::StorageClass::kOutput)) {
AddError("invalid use of input/output storage class", var->source());
return false;
}
return true;
}
bool Resolver::ValidateFunctionParameter(const ast::Function* func,
const VariableInfo* info) {
if (!ValidateVariable(info)) {
return false;
}
for (auto* deco : info->declaration->decorations()) {
if (!func->IsEntryPoint() && !deco->Is<ast::InternalDecoration>()) {
AddError(
"decoration is not valid for non-entry point function parameters",
deco->source());
return false;
} else if (!deco->IsAnyOf<ast::BuiltinDecoration, ast::InvariantDecoration,
ast::LocationDecoration,
ast::InterpolateDecoration,
ast::InternalDecoration>() &&
(IsValidationEnabled(
info->declaration->decorations(),
ast::DisabledValidation::kEntryPointParameter) &&
IsValidationEnabled(
info->declaration->decorations(),
ast::DisabledValidation::
kIgnoreConstructibleFunctionParameter))) {
AddError("decoration is not valid for function parameters",
deco->source());
return false;
}
}
if (auto* ref = info->type->As<sem::Pointer>()) {
auto sc = ref->StorageClass();
if (!(sc == ast::StorageClass::kFunction ||
sc == ast::StorageClass::kPrivate ||
sc == ast::StorageClass::kWorkgroup)) {
std::stringstream ss;
ss << "function parameter of pointer type cannot be in '" << sc
<< "' storage class";
AddError(ss.str(), info->declaration->source());
return false;
}
}
if (IsPlain(info->type)) {
if (!info->type->IsConstructible() &&
IsValidationEnabled(
info->declaration->decorations(),
ast::DisabledValidation::kIgnoreConstructibleFunctionParameter)) {
AddError("store type of function parameter must be a constructible type",
info->declaration->source());
return false;
}
} else if (!info->type->IsAnyOf<sem::Texture, sem::Sampler, sem::Pointer>()) {
AddError("store type of function parameter cannot be " +
info->type->FriendlyName(builder_->Symbols()),
info->declaration->source());
return false;
}
return true;
}
bool Resolver::ValidateBuiltinDecoration(const ast::BuiltinDecoration* deco,
const sem::Type* storage_type,
const bool is_input,
const bool is_struct_member) {
auto* type = storage_type->UnwrapRef();
const auto stage = current_function_
? current_function_->declaration->pipeline_stage()
: ast::PipelineStage::kNone;
std::stringstream stage_name;
stage_name << stage;
bool is_stage_mismatch = false;
bool is_output = !is_input;
switch (deco->value()) {
case ast::Builtin::kPosition:
if (stage != ast::PipelineStage::kNone &&
!((is_input && stage == ast::PipelineStage::kFragment) ||
(is_output && stage == ast::PipelineStage::kVertex))) {
is_stage_mismatch = true;
}
if (!(type->is_float_vector() && type->As<sem::Vector>()->Width() == 4)) {
AddError("store type of " + deco_to_str(deco) + " must be 'vec4<f32>'",
deco->source());
return false;
}
break;
case ast::Builtin::kGlobalInvocationId:
case ast::Builtin::kLocalInvocationId:
case ast::Builtin::kWorkgroupId:
if (stage != ast::PipelineStage::kNone &&
!(stage == ast::PipelineStage::kCompute && is_input)) {
is_stage_mismatch = true;
}
if (!(type->is_unsigned_integer_vector() &&
type->As<sem::Vector>()->Width() == 3)) {
AddError("store type of " + deco_to_str(deco) + " must be 'vec3<u32>'",
deco->source());
return false;
}
break;
case ast::Builtin::kFragDepth:
if (stage != ast::PipelineStage::kNone &&
!(stage == ast::PipelineStage::kFragment && !is_input)) {
is_stage_mismatch = true;
}
if (!type->Is<sem::F32>()) {
AddError("store type of " + deco_to_str(deco) + " must be 'f32'",
deco->source());
return false;
}
break;
case ast::Builtin::kFrontFacing:
if (stage != ast::PipelineStage::kNone &&
!(stage == ast::PipelineStage::kFragment && is_input)) {
is_stage_mismatch = true;
}
if (!type->Is<sem::Bool>()) {
AddError("store type of " + deco_to_str(deco) + " must be 'bool'",
deco->source());
return false;
}
break;
case ast::Builtin::kLocalInvocationIndex:
if (stage != ast::PipelineStage::kNone &&
!(stage == ast::PipelineStage::kCompute && is_input)) {
is_stage_mismatch = true;
}
if (!type->Is<sem::U32>()) {
AddError("store type of " + deco_to_str(deco) + " must be 'u32'",
deco->source());
return false;
}
break;
case ast::Builtin::kVertexIndex:
case ast::Builtin::kInstanceIndex:
if (stage != ast::PipelineStage::kNone &&
!(stage == ast::PipelineStage::kVertex && is_input)) {
is_stage_mismatch = true;
}
if (!type->Is<sem::U32>()) {
AddError("store type of " + deco_to_str(deco) + " must be 'u32'",
deco->source());
return false;
}
break;
case ast::Builtin::kSampleMask:
if (stage != ast::PipelineStage::kNone &&
!(stage == ast::PipelineStage::kFragment)) {
is_stage_mismatch = true;
}
if (!type->Is<sem::U32>()) {
AddError("store type of " + deco_to_str(deco) + " must be 'u32'",
deco->source());
return false;
}
break;
case ast::Builtin::kSampleIndex:
if (stage != ast::PipelineStage::kNone &&
!(stage == ast::PipelineStage::kFragment && is_input)) {
is_stage_mismatch = true;
}
if (!type->Is<sem::U32>()) {
AddError("store type of " + deco_to_str(deco) + " must be 'u32'",
deco->source());
return false;
}
break;
case ast::Builtin::kNumWorkgroups:
// TODO(crbug.com/tint/752): Backend support (needs extra work for HLSL).
AddError("num_workgroups builtin is not yet implemented", deco->source());
return false;
default:
break;
}
// ignore builtin attribute on struct members to facillate data movement
// between stages
if (!is_struct_member) {
if (is_stage_mismatch) {
AddError(deco_to_str(deco) + " cannot be used in " +
(is_input ? "input of " : "output of ") + stage_name.str() +
" pipeline stage",
deco->source());
return false;
}
}
return true;
}
bool Resolver::ValidateInterpolateDecoration(
const ast::InterpolateDecoration* deco,
const sem::Type* storage_type) {
auto* type = storage_type->UnwrapRef();
if (!type->is_float_scalar_or_vector()) {
AddError(
"store type of interpolate attribute must be floating point scalar or "
"vector",
deco->source());
return false;
}
if (deco->type() == ast::InterpolationType::kFlat &&
deco->sampling() != ast::InterpolationSampling::kNone) {
AddError("flat interpolation attribute must not have a sampling parameter",
deco->source());
return false;
}
return true;
}
bool Resolver::ValidateFunction(const ast::Function* func,
const FunctionInfo* info) {
if (!ValidateNoDuplicateDefinition(func->symbol(), func->source(),
/* check_global_scope_only */ true)) {
return false;
}
auto workgroup_deco_count = 0;
for (auto* deco : func->decorations()) {
if (deco->Is<ast::WorkgroupDecoration>()) {
workgroup_deco_count++;
if (func->pipeline_stage() != ast::PipelineStage::kCompute) {
AddError(
"the workgroup_size attribute is only valid for compute stages",
deco->source());
return false;
}
} else if (!deco->IsAnyOf<ast::StageDecoration,
ast::InternalDecoration>()) {
AddError("decoration is not valid for functions", deco->source());
return false;
}
}
if (func->params().size() > 255) {
AddError("functions may declare at most 255 parameters", func->source());
return false;
}
for (auto* param : func->params()) {
if (!ValidateFunctionParameter(func, variable_to_info_.at(param))) {
return false;
}
}
if (!info->return_type->Is<sem::Void>()) {
if (!info->return_type->IsConstructible()) {
AddError("function return type must be a constructible type",
func->return_type()->source());
return false;
}
if (func->body()) {
if (!func->get_last_statement() ||
!func->get_last_statement()->Is<ast::ReturnStatement>()) {
AddError("non-void function must end with a return statement",
func->source());
return false;
}
} else if (IsValidationEnabled(
func->decorations(),
ast::DisabledValidation::kFunctionHasNoBody)) {
TINT_ICE(Resolver, diagnostics_)
<< "Function " << builder_->Symbols().NameFor(func->symbol())
<< " has no body";
}
for (auto* deco : func->return_type_decorations()) {
if (!func->IsEntryPoint()) {
AddError(
"decoration is not valid for non-entry point function return types",
deco->source());
return false;
}
if (!deco->IsAnyOf<ast::BuiltinDecoration, ast::InternalDecoration,
ast::LocationDecoration, ast::InterpolateDecoration,
ast::InvariantDecoration>() &&
(IsValidationEnabled(info->declaration->decorations(),
ast::DisabledValidation::kEntryPointParameter) &&
IsValidationEnabled(info->declaration->decorations(),
ast::DisabledValidation::
kIgnoreConstructibleFunctionParameter))) {
AddError("decoration is not valid for entry point return types",
deco->source());
return false;
}
}
}
if (func->IsEntryPoint()) {
if (!ValidateEntryPoint(func, info)) {
return false;
}
}
return true;
}
bool Resolver::ValidateEntryPoint(const ast::Function* func,
const FunctionInfo* info) {
// Use a lambda to validate the entry point decorations for a type.
// Persistent state is used to track which builtins and locations have
// already been seen, in order to catch conflicts.
// TODO(jrprice): This state could be stored in FunctionInfo instead, and
// then passed to sem::Function since it would be useful there too.
std::unordered_set<ast::Builtin> builtins;
std::unordered_set<uint32_t> locations;
enum class ParamOrRetType {
kParameter,
kReturnType,
};
// Inner lambda that is applied to a type and all of its members.
auto validate_entry_point_decorations_inner = [&](const ast::DecorationList&
decos,
sem::Type* ty,
Source source,
ParamOrRetType param_or_ret,
bool is_struct_member) {
// Scan decorations for pipeline IO attributes.
// Check for overlap with attributes that have been seen previously.
ast::Decoration* pipeline_io_attribute = nullptr;
ast::InvariantDecoration* invariant_attribute = nullptr;
for (auto* deco : decos) {
auto is_invalid_compute_shader_decoration = false;
if (auto* builtin = deco->As<ast::BuiltinDecoration>()) {
if (pipeline_io_attribute) {
AddError("multiple entry point IO attributes", deco->source());
AddNote("previously consumed " + deco_to_str(pipeline_io_attribute),
pipeline_io_attribute->source());
return false;
}
pipeline_io_attribute = deco;
if (builtins.count(builtin->value())) {
AddError(deco_to_str(builtin) +
" attribute appears multiple times as pipeline " +
(param_or_ret == ParamOrRetType::kParameter ? "input"
: "output"),
func->source());
return false;
}
if (!ValidateBuiltinDecoration(
builtin, ty,
/* is_input */ param_or_ret == ParamOrRetType::kParameter,
/* is_struct_member */ is_struct_member)) {
return false;
}
builtins.emplace(builtin->value());
} else if (auto* location = deco->As<ast::LocationDecoration>()) {
if (pipeline_io_attribute) {
AddError("multiple entry point IO attributes", deco->source());
AddNote("previously consumed " + deco_to_str(pipeline_io_attribute),
pipeline_io_attribute->source());
return false;
}
pipeline_io_attribute = deco;
bool is_input = param_or_ret == ParamOrRetType::kParameter;
if (!ValidateLocationDecoration(location, ty, locations, source,
is_input)) {
return false;
}
} else if (auto* interpolate = deco->As<ast::InterpolateDecoration>()) {
if (func->pipeline_stage() == ast::PipelineStage::kCompute) {
is_invalid_compute_shader_decoration = true;
} else if (!ValidateInterpolateDecoration(interpolate, ty)) {
return false;
}
} else if (auto* invariant = deco->As<ast::InvariantDecoration>()) {
if (func->pipeline_stage() == ast::PipelineStage::kCompute) {
is_invalid_compute_shader_decoration = true;
}
invariant_attribute = invariant;
}
if (is_invalid_compute_shader_decoration) {
std::string input_or_output =
param_or_ret == ParamOrRetType::kParameter ? "inputs" : "output";
AddError(
"decoration is not valid for compute shader " + input_or_output,
deco->source());
return false;
}
}
if (IsValidationEnabled(decos,
ast::DisabledValidation::kEntryPointParameter)) {
if (!ty->Is<sem::Struct>() && !pipeline_io_attribute) {
std::string err = "missing entry point IO attribute";
if (!is_struct_member) {
err +=
(param_or_ret == ParamOrRetType::kParameter ? " on parameter"
: " on return type");
}
AddError(err, source);
return false;
}
if (invariant_attribute) {
bool has_position = false;
if (pipeline_io_attribute) {
if (auto* builtin =
pipeline_io_attribute->As<ast::BuiltinDecoration>()) {
has_position = (builtin->value() == ast::Builtin::kPosition);
}
}
if (!has_position) {
AddError(
"invariant attribute must only be applied to a position "
"builtin",
invariant_attribute->source());
return false;
}
}
}
return true;
};
// Outer lambda for validating the entry point decorations for a type.
auto validate_entry_point_decorations = [&](const ast::DecorationList& decos,
sem::Type* ty, Source source,
ParamOrRetType param_or_ret) {
if (!validate_entry_point_decorations_inner(decos, ty, source, param_or_ret,
/*is_struct_member*/ false)) {
return false;
}
if (auto* str = ty->As<sem::Struct>()) {
for (auto* member : str->Members()) {
if (!validate_entry_point_decorations_inner(
member->Declaration()->decorations(), member->Type(),
member->Declaration()->source(), param_or_ret,
/*is_struct_member*/ true)) {
AddNote("while analysing entry point '" +
builder_->Symbols().NameFor(func->symbol()) + "'",
func->source());
return false;
}
}
}
return true;
};
for (auto* param : info->parameters) {
if (!validate_entry_point_decorations(
param->declaration->decorations(), param->type,
param->declaration->source(), ParamOrRetType::kParameter)) {
return false;
}
}
// Clear IO sets after parameter validation. Builtin and location attributes
// in return types should be validated independently from those used in
// parameters.
builtins.clear();
locations.clear();
if (!info->return_type->Is<sem::Void>()) {
if (!validate_entry_point_decorations(func->return_type_decorations(),
info->return_type, func->source(),
ParamOrRetType::kReturnType)) {
return false;
}
}
if (func->pipeline_stage() == ast::PipelineStage::kVertex &&
builtins.count(ast::Builtin::kPosition) == 0) {
// Check module-scope variables, as the SPIR-V sanitizer generates these.
bool found = false;
for (auto* var : info->referenced_module_vars) {
if (auto* builtin = ast::GetDecoration<ast::BuiltinDecoration>(
var->declaration->decorations())) {
if (builtin->value() == ast::Builtin::kPosition) {
found = true;
break;
}
}
}
if (!found) {
AddError(
"a vertex shader must include the 'position' builtin in its return "
"type",
func->source());
return false;
}
}
if (func->pipeline_stage() == ast::PipelineStage::kCompute) {
if (!ast::HasDecoration<ast::WorkgroupDecoration>(func->decorations())) {
AddError(
"a compute shader must include 'workgroup_size' in its "
"attributes",
func->source());
return false;
}
}
// Validate there are no resource variable binding collisions
std::unordered_map<sem::BindingPoint, const ast::Variable*> binding_points;
for (auto* var_info : info->referenced_module_vars) {
if (!var_info->declaration->binding_point()) {
continue;
}
auto bp = var_info->binding_point;
auto res = binding_points.emplace(bp, var_info->declaration);
if (!res.second &&
IsValidationEnabled(var_info->declaration->decorations(),
ast::DisabledValidation::kBindingPointCollision) &&
IsValidationEnabled(res.first->second->decorations(),
ast::DisabledValidation::kBindingPointCollision)) {
// https://gpuweb.github.io/gpuweb/wgsl/#resource-interface
// Bindings must not alias within a shader stage: two different
// variables in the resource interface of a given shader must not have
// the same group and binding values, when considered as a pair of
// values.
auto func_name = builder_->Symbols().NameFor(info->declaration->symbol());
AddError("entry point '" + func_name +
"' references multiple variables that use the "
"same resource binding [[group(" +
std::to_string(bp.group) + "), binding(" +
std::to_string(bp.binding) + ")]]",
var_info->declaration->source());
AddNote("first resource binding usage declared here",
res.first->second->source());
return false;
}
}
return true;
}
bool Resolver::Function(ast::Function* func) {
auto* info = function_infos_.Create<FunctionInfo>(func);
if (func->IsEntryPoint()) {
entry_points_.emplace_back(info);
}
TINT_SCOPED_ASSIGNMENT(current_function_, info);
variable_stack_.push_scope();
uint32_t parameter_index = 0;
for (auto* param : func->params()) {
Mark(param);
auto* param_info =
Variable(param, VariableKind::kParameter, parameter_index++);
if (!param_info) {
return false;
}
for (auto* deco : param->decorations()) {
Mark(deco);
}
if (!ValidateNoDuplicateDecorations(param->decorations())) {
return false;
}
variable_stack_.set(param->symbol(), param_info);
info->parameters.emplace_back(param_info);
if (!ApplyStorageClassUsageToType(param->declared_storage_class(),
param_info->type, param->source())) {
AddNote("while instantiating parameter " +
builder_->Symbols().NameFor(param->symbol()),
param->source());
return false;
}
if (auto* str = param_info->type->As<sem::Struct>()) {
switch (func->pipeline_stage()) {
case ast::PipelineStage::kVertex:
str->AddUsage(sem::PipelineStageUsage::kVertexInput);
break;
case ast::PipelineStage::kFragment:
str->AddUsage(sem::PipelineStageUsage::kFragmentInput);
break;
case ast::PipelineStage::kCompute:
str->AddUsage(sem::PipelineStageUsage::kComputeInput);
break;
case ast::PipelineStage::kNone:
break;
}
}
}
if (auto* ty = func->return_type()) {
info->return_type = Type(ty);
info->return_type_name = ty->FriendlyName(builder_->Symbols());
if (!info->return_type) {
return false;
}
} else {
info->return_type = builder_->create<sem::Void>();
info->return_type_name =
info->return_type->FriendlyName(builder_->Symbols());
}
if (auto* str = info->return_type->As<sem::Struct>()) {
if (!ApplyStorageClassUsageToType(ast::StorageClass::kNone, str,
func->source())) {
AddNote("while instantiating return type for " +
builder_->Symbols().NameFor(func->symbol()),
func->source());
return false;
}
switch (func->pipeline_stage()) {
case ast::PipelineStage::kVertex:
str->AddUsage(sem::PipelineStageUsage::kVertexOutput);
break;
case ast::PipelineStage::kFragment:
str->AddUsage(sem::PipelineStageUsage::kFragmentOutput);
break;
case ast::PipelineStage::kCompute:
str->AddUsage(sem::PipelineStageUsage::kComputeOutput);
break;
case ast::PipelineStage::kNone:
break;
}
}
if (func->body()) {
Mark(func->body());
if (current_compound_statement_) {
TINT_ICE(Resolver, diagnostics_)
<< "Resolver::Function() called with a current compound statement";
return false;
}
auto* sem_block = builder_->create<sem::FunctionBlockStatement>(func);
builder_->Sem().Add(func->body(), sem_block);
if (!Scope(sem_block, [&] { return Statements(func->body()->list()); })) {
return false;
}
}
variable_stack_.pop_scope();
for (auto* deco : func->decorations()) {
Mark(deco);
}
if (!ValidateNoDuplicateDecorations(func->decorations())) {
return false;
}
for (auto* deco : func->return_type_decorations()) {
Mark(deco);
}
if (!ValidateNoDuplicateDecorations(func->return_type_decorations())) {
return false;
}
// Set work-group size defaults.
for (int i = 0; i < 3; i++) {
info->workgroup_size[i].value = 1;
info->workgroup_size[i].overridable_const = nullptr;
}
if (auto* workgroup =
ast::GetDecoration<ast::WorkgroupDecoration>(func->decorations())) {
auto values = workgroup->values();
auto any_i32 = false;
auto any_u32 = false;
for (int i = 0; i < 3; i++) {
// Each argument to this decoration can either be a literal, an
// identifier for a module-scope constants, or nullptr if not specified.
auto* expr = values[i];
if (!expr) {
// Not specified, just use the default.
continue;
}
Mark(expr);
if (!Expression(expr)) {
return false;
}
constexpr const char* kErrBadType =
"workgroup_size parameter must be either literal or module-scope "
"constant of type i32 or u32";
constexpr const char* kErrInconsistentType =
"workgroup_size parameters must be of the same type, either i32 "
"or u32";
auto* ty = TypeOf(expr);
bool is_i32 = ty->UnwrapRef()->Is<sem::I32>();
bool is_u32 = ty->UnwrapRef()->Is<sem::U32>();
if (!is_i32 && !is_u32) {
AddError(kErrBadType, expr->source());
return false;
}
any_i32 = any_i32 || is_i32;
any_u32 = any_u32 || is_u32;
if (any_i32 && any_u32) {
AddError(kErrInconsistentType, expr->source());
return false;
}
if (auto* ident = expr->As<ast::IdentifierExpression>()) {
// We have an identifier of a module-scope constant.
VariableInfo* var = nullptr;
if (!variable_stack_.get(ident->symbol(), &var) ||
!(var->declaration->is_const())) {
AddError(kErrBadType, expr->source());
return false;
}
// Capture the constant if an [[override]] attribute is present.
if (ast::HasDecoration<ast::OverrideDecoration>(
var->declaration->decorations())) {
info->workgroup_size[i].overridable_const = var->declaration;
}
expr = var->declaration->constructor();
if (!expr) {
// No constructor means this value must be overriden by the user.
info->workgroup_size[i].value = 0;
continue;
}
}
auto val = ConstantValueOf(expr);
if (!val) {
TINT_ICE(Resolver, diagnostics_)
<< "could not resolve constant workgroup_size constant value";
continue;
}
// Validate and set the default value for this dimension.
if (is_i32 ? val.Elements()[0].i32 < 1 : val.Elements()[0].u32 < 1) {
AddError("workgroup_size parameter must be at least 1",
values[i]->source());
return false;
}
info->workgroup_size[i].value =
is_i32 ? static_cast<uint32_t>(val.Elements()[0].i32)
: val.Elements()[0].u32;
}
}
if (!ValidateFunction(func, info)) {
return false;
}
// Register the function information _after_ processing the statements. This
// allows us to catch a function calling itself when determining the call
// information as this function doesn't exist until it's finished.
symbol_to_function_[func->symbol()] = info;
function_to_info_.emplace(func, info);
return true;
}
bool Resolver::Statements(const ast::StatementList& stmts) {
for (auto* stmt : stmts) {
Mark(stmt);
if (!Statement(stmt)) {
return false;
}
}
if (!ValidateStatements(stmts)) {
return false;
}
return true;
}
bool Resolver::ValidateStatements(const ast::StatementList& stmts) {
auto next_stmt = stmts.begin();
for (auto* stmt : stmts) {
next_stmt++;
if (stmt->IsAnyOf<ast::ReturnStatement, ast::BreakStatement,
ast::ContinueStatement>()) {
if (stmt != stmts.back()) {
AddError("code is unreachable", (*next_stmt)->source());
return false;
}
}
}
return true;
}
bool Resolver::Statement(ast::Statement* stmt) {
if (stmt->Is<ast::CaseStatement>()) {
AddError("case statement can only be used inside a switch statement",
stmt->source());
return false;
}
if (stmt->Is<ast::ElseStatement>()) {
TINT_ICE(Resolver, diagnostics_)
<< "Resolver::Statement() encountered an Else statement. Else "
"statements are embedded in If statements, so should never be "
"encountered as top-level statements";
return false;
}
// Compound statements. These create their own sem::CompoundStatement
// bindings.
if (auto* b = stmt->As<ast::BlockStatement>()) {
return BlockStatement(b);
}
if (auto* l = stmt->As<ast::ForLoopStatement>()) {
return ForLoopStatement(l);
}
if (auto* l = stmt->As<ast::LoopStatement>()) {
return LoopStatement(l);
}
if (auto* i = stmt->As<ast::IfStatement>()) {
return IfStatement(i);
}
if (auto* s = stmt->As<ast::SwitchStatement>()) {
return SwitchStatement(s);
}
// Non-Compound statements
sem::Statement* sem_statement =
builder_->create<sem::Statement>(stmt, current_compound_statement_);
builder_->Sem().Add(stmt, sem_statement);
TINT_SCOPED_ASSIGNMENT(current_statement_, sem_statement);
if (auto* a = stmt->As<ast::AssignmentStatement>()) {
return Assignment(a);
}
if (stmt->Is<ast::BreakStatement>()) {
if (!sem_statement->FindFirstParent<sem::LoopBlockStatement>() &&
!sem_statement->FindFirstParent<sem::SwitchCaseBlockStatement>()) {
AddError("break statement must be in a loop or switch case",
stmt->source());
return false;
}
return true;
}
if (auto* c = stmt->As<ast::CallStatement>()) {
Mark(c->expr());
if (!Expression(c->expr())) {
return false;
}
if (!ValidateCallStatement(c)) {
return false;
}
return true;
}
if (stmt->Is<ast::ContinueStatement>()) {
// Set if we've hit the first continue statement in our parent loop
if (auto* block =
current_block_->FindFirstParent<
sem::LoopBlockStatement, sem::LoopContinuingBlockStatement>()) {
if (auto* loop_block = block->As<sem::LoopBlockStatement>()) {
if (loop_block->FirstContinue() == size_t(~0)) {
const_cast<sem::LoopBlockStatement*>(loop_block)
->SetFirstContinue(loop_block->Decls().size());
}
} else {
AddError("continuing blocks must not contain a continue statement",
stmt->source());
return false;
}
} else {
AddError("continue statement must be in a loop", stmt->source());
return false;
}
return true;
}
if (stmt->Is<ast::DiscardStatement>()) {
if (auto* continuing =
sem_statement
->FindFirstParent<sem::LoopContinuingBlockStatement>()) {
AddError("continuing blocks must not contain a discard statement",
stmt->source());
if (continuing != sem_statement->Parent()) {
AddNote("see continuing block here",
continuing->Declaration()->source());
}
return false;
}
return true;
}
if (stmt->Is<ast::FallthroughStatement>()) {
return true;
}
if (auto* r = stmt->As<ast::ReturnStatement>()) {
return Return(r);
}
if (auto* v = stmt->As<ast::VariableDeclStatement>()) {
return VariableDeclStatement(v);
}
AddError(
"unknown statement type for type determination: " + builder_->str(stmt),
stmt->source());
return false;
}
bool Resolver::CaseStatement(ast::CaseStatement* stmt) {
auto* sem = builder_->create<sem::SwitchCaseBlockStatement>(
stmt->body(), current_compound_statement_);
builder_->Sem().Add(stmt, sem);
builder_->Sem().Add(stmt->body(), sem);
Mark(stmt->body());
for (auto* sel : stmt->selectors()) {
Mark(sel);
}
return Scope(sem, [&] { return Statements(stmt->body()->list()); });
}
bool Resolver::IfStatement(ast::IfStatement* stmt) {
auto* sem =
builder_->create<sem::IfStatement>(stmt, current_compound_statement_);
builder_->Sem().Add(stmt, sem);
return Scope(sem, [&] {
Mark(stmt->condition());
if (!Expression(stmt->condition())) {
return false;
}
auto* cond_type = TypeOf(stmt->condition())->UnwrapRef();
if (!cond_type->Is<sem::Bool>()) {
AddError("if statement condition must be bool, got " +
cond_type->FriendlyName(builder_->Symbols()),
stmt->condition()->source());
return false;
}
Mark(stmt->body());
auto* body = builder_->create<sem::BlockStatement>(
stmt->body(), current_compound_statement_);
builder_->Sem().Add(stmt->body(), body);
if (!Scope(body, [&] { return Statements(stmt->body()->list()); })) {
return false;
}
for (auto* else_stmt : stmt->else_statements()) {
Mark(else_stmt);
if (!ElseStatement(else_stmt)) {
return false;
}
}
return true;
});
}
bool Resolver::ElseStatement(ast::ElseStatement* stmt) {
auto* sem =
builder_->create<sem::ElseStatement>(stmt, current_compound_statement_);
builder_->Sem().Add(stmt, sem);
return Scope(sem, [&] {
if (auto* cond = stmt->condition()) {
Mark(cond);
if (!Expression(cond)) {
return false;
}
auto* else_cond_type = TypeOf(cond)->UnwrapRef();
if (!else_cond_type->Is<sem::Bool>()) {
AddError("else statement condition must be bool, got " +
else_cond_type->FriendlyName(builder_->Symbols()),
cond->source());
return false;
}
}
Mark(stmt->body());
auto* body = builder_->create<sem::BlockStatement>(
stmt->body(), current_compound_statement_);
builder_->Sem().Add(stmt->body(), body);
return Scope(body, [&] { return Statements(stmt->body()->list()); });
});
}
bool Resolver::BlockStatement(ast::BlockStatement* stmt) {
auto* sem = builder_->create<sem::BlockStatement>(
stmt->As<ast::BlockStatement>(), current_compound_statement_);
builder_->Sem().Add(stmt, sem);
return Scope(sem, [&] { return Statements(stmt->list()); });
}
bool Resolver::LoopStatement(ast::LoopStatement* stmt) {
auto* sem =
builder_->create<sem::LoopStatement>(stmt, current_compound_statement_);
builder_->Sem().Add(stmt, sem);
return Scope(sem, [&] {
Mark(stmt->body());
auto* body = builder_->create<sem::LoopBlockStatement>(
stmt->body(), current_compound_statement_);
builder_->Sem().Add(stmt->body(), body);
return Scope(body, [&] {
if (!Statements(stmt->body()->list())) {
return false;
}
if (stmt->continuing()) { // has_continuing() also checks for empty()
Mark(stmt->continuing());
}
if (stmt->has_continuing()) {
auto* continuing = builder_->create<sem::LoopContinuingBlockStatement>(
stmt->continuing(), current_compound_statement_);
builder_->Sem().Add(stmt->continuing(), continuing);
if (!Scope(continuing,
[&] { return Statements(stmt->continuing()->list()); })) {
return false;
}
}
return true;
});
});
}
bool Resolver::ForLoopStatement(ast::ForLoopStatement* stmt) {
auto* sem = builder_->create<sem::ForLoopStatement>(
stmt, current_compound_statement_);
builder_->Sem().Add(stmt, sem);
return Scope(sem, [&] {
if (auto* initializer = stmt->initializer()) {
Mark(initializer);
if (!Statement(initializer)) {
return false;
}
}
if (auto* condition = stmt->condition()) {
Mark(condition);
if (!Expression(condition)) {
return false;
}
if (!TypeOf(condition)->UnwrapRef()->Is<sem::Bool>()) {
AddError(
"for-loop condition must be bool, got " + TypeNameOf(condition),
condition->source());
return false;
}
}
if (auto* continuing = stmt->continuing()) {
Mark(continuing);
if (!Statement(continuing)) {
return false;
}
}
Mark(stmt->body());
auto* body = builder_->create<sem::LoopBlockStatement>(
stmt->body(), current_compound_statement_);
builder_->Sem().Add(stmt->body(), body);
return Scope(body, [&] { return Statements(stmt->body()->statements()); });
});
}
bool Resolver::Expressions(const ast::ExpressionList& list) {
for (auto* expr : list) {
Mark(expr);
if (!Expression(expr)) {
return false;
}
}
return true;
}
bool Resolver::Expression(ast::Expression* expr) {
if (TypeOf(expr)) {
return true; // Already resolved
}
bool ok = false;
if (auto* array = expr->As<ast::ArrayAccessorExpression>()) {
ok = ArrayAccessor(array);
} else if (auto* bin_op = expr->As<ast::BinaryExpression>()) {
ok = Binary(bin_op);
} else if (auto* bitcast = expr->As<ast::BitcastExpression>()) {
ok = Bitcast(bitcast);
} else if (auto* call = expr->As<ast::CallExpression>()) {
ok = Call(call);
} else if (auto* ctor = expr->As<ast::ConstructorExpression>()) {
ok = Constructor(ctor);
} else if (auto* ident = expr->As<ast::IdentifierExpression>()) {
ok = Identifier(ident);
} else if (auto* member = expr->As<ast::MemberAccessorExpression>()) {
ok = MemberAccessor(member);
} else if (auto* unary = expr->As<ast::UnaryOpExpression>()) {
ok = UnaryOp(unary);
} else {
AddError("unknown expression for type determination", expr->source());
}
if (!ok) {
return false;
}
return true;
}
bool Resolver::ArrayAccessor(ast::ArrayAccessorExpression* expr) {
Mark(expr->array());
if (!Expression(expr->array())) {
return false;
}
auto* idx = expr->idx_expr();
Mark(idx);
if (!Expression(idx)) {
return false;
}
auto* res = TypeOf(expr->array());
auto* parent_type = res->UnwrapRef();
const sem::Type* ret = nullptr;
if (auto* arr = parent_type->As<sem::Array>()) {
ret = arr->ElemType();
} else if (auto* vec = parent_type->As<sem::Vector>()) {
ret = vec->type();
} else if (auto* mat = parent_type->As<sem::Matrix>()) {
ret = builder_->create<sem::Vector>(mat->type(), mat->rows());
} else {
AddError("invalid parent type (" + parent_type->type_name() +
") in array accessor",
expr->source());
return false;
}
if (!TypeOf(idx)->UnwrapRef()->IsAnyOf<sem::I32, sem::U32>()) {
AddError("index must be of type 'i32' or 'u32', found: '" +
TypeNameOf(idx) + "'",
idx->source());
return false;
}
if (parent_type->Is<sem::Array>() || parent_type->Is<sem::Matrix>()) {
if (!res->Is<sem::Reference>()) {
// TODO(bclayton): expand this to allow any const_expr expression
// https://github.com/gpuweb/gpuweb/issues/1272
auto* scalar = idx->As<ast::ScalarConstructorExpression>();
if (!scalar || !scalar->literal()->As<ast::IntLiteral>()) {
AddError("index must be signed or unsigned integer literal",
idx->source());
return false;
}
}
}
// If we're extracting from a reference, we return a reference.
if (auto* ref = res->As<sem::Reference>()) {
ret = builder_->create<sem::Reference>(ret, ref->StorageClass(),
ref->Access());
}
SetExprInfo(expr, ret);
return true;
}
bool Resolver::Bitcast(ast::BitcastExpression* expr) {
Mark(expr->expr());
if (!Expression(expr->expr())) {
return false;
}
auto* ty = Type(expr->type());
if (!ty) {
return false;
}
if (ty->Is<sem::Pointer>()) {
AddError("cannot cast to a pointer", expr->source());
return false;
}
SetExprInfo(expr, ty, expr->type()->FriendlyName(builder_->Symbols()));
return true;
}
bool Resolver::Call(ast::CallExpression* call) {
if (!Expressions(call->params())) {
return false;
}
Mark(call->func());
auto* ident = call->func();
auto name = builder_->Symbols().NameFor(ident->symbol());
auto intrinsic_type = sem::ParseIntrinsicType(name);
if (intrinsic_type != IntrinsicType::kNone) {
if (!IntrinsicCall(call, intrinsic_type)) {
return false;
}
} else {
if (!FunctionCall(call)) {
return false;
}
}
return true;
}
bool Resolver::ValidateCallStatement(ast::CallStatement* stmt) {
const sem::Type* return_type = nullptr;
// A function call is made to either a user declared function or an intrinsic.
// function_calls_ only maps CallExpression to user declared functions
auto it = function_calls_.find(stmt->expr());
if (it != function_calls_.end()) {
return_type = it->second.function->return_type;
} else {
// Must be an intrinsic call
auto* target = builder_->Sem().Get(stmt->expr())->Target();
if (auto* intrinsic = target->As<sem::Intrinsic>()) {
return_type = intrinsic->ReturnType();
} else {
TINT_ICE(Resolver, diagnostics_)
<< "call target was not an intrinsic, but a "
<< intrinsic->TypeInfo().name;
}
}
if (!return_type->Is<sem::Void>()) {
// https://gpuweb.github.io/gpuweb/wgsl/#function-call-statement
// A function call statement executes a function call where the called
// function does not return a value. If the called function returns a value,
// that value must be consumed either through assignment, evaluation in
// another expression or through use of the ignore built-in function (see
// § 16.13 Value-steering functions).
AddError(
"result of called function was not used. If this was intentional wrap "
"the function call in ignore()",
stmt->source());
return false;
}
return true;
}
bool Resolver::IntrinsicCall(ast::CallExpression* call,
sem::IntrinsicType intrinsic_type) {
std::vector<const sem::Type*> arg_tys;
arg_tys.reserve(call->params().size());
for (auto* expr : call->params()) {
arg_tys.emplace_back(TypeOf(expr));
}
auto* result =
intrinsic_table_->Lookup(intrinsic_type, arg_tys, call->source());
if (!result) {
return false;
}
if (result->IsDeprecated()) {
AddWarning("use of deprecated intrinsic", call->source());
}
auto* out = builder_->create<sem::Call>(call, result, current_statement_);
builder_->Sem().Add(call, out);
SetExprInfo(call, result->ReturnType());
current_function_->intrinsic_calls.emplace_back(
IntrinsicCallInfo{call, result});
if (IsTextureIntrinsic(intrinsic_type) &&
!ValidateTextureIntrinsicFunction(call, out)) {
return false;
}
return true;
}
bool Resolver::ValidateTextureIntrinsicFunction(
const ast::CallExpression* ast_call,
const sem::Call* sem_call) {
auto* intrinsic = sem_call->Target()->As<sem::Intrinsic>();
if (!intrinsic) {
return false;
}
std::string func_name = intrinsic->str();
auto index =
sem::IndexOf(intrinsic->Parameters(), sem::ParameterUsage::kOffset);
if (index > -1) {
auto* param = ast_call->params()[index];
if (param->Is<ast::TypeConstructorExpression>()) {
auto values = ConstantValueOf(param);
if (!values.IsValid()) {
AddError(
"'" + func_name + "' offset parameter must be a const_expression",
param->source());
return false;
}
if (!values.Type()->Is<sem::Vector>() ||
!values.ElementType()->Is<sem::I32>()) {
TINT_ICE(Resolver, diagnostics_)
<< "failed to resolve '" + func_name + "' offset parameter type";
return false;
}
for (auto offset : values.Elements()) {
auto offset_value = offset.i32;
if (offset_value < -8 || offset_value > 7) {
AddError("each offset component of '" + func_name +
"' must be at least -8 and at most 7. "
"found: '" +
std::to_string(offset_value) + "'",
param->source());
return false;
}
}
} else {
AddError(
"'" + func_name + "' offset parameter must be a const_expression",
param->source());
return false;
}
}
return true;
}
bool Resolver::FunctionCall(const ast::CallExpression* call) {
auto* ident = call->func();
auto name = builder_->Symbols().NameFor(ident->symbol());
auto callee_func_it = symbol_to_function_.find(ident->symbol());
if (callee_func_it == symbol_to_function_.end()) {
if (current_function_ &&
current_function_->declaration->symbol() == ident->symbol()) {
AddError("recursion is not permitted. '"