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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/tint/writer/msl/generator_impl.h"
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <limits>
#include <utility>
#include <vector>
#include "src/tint/ast/alias.h"
#include "src/tint/ast/bool_literal_expression.h"
#include "src/tint/ast/call_statement.h"
#include "src/tint/ast/disable_validation_attribute.h"
#include "src/tint/ast/float_literal_expression.h"
#include "src/tint/ast/id_attribute.h"
#include "src/tint/ast/interpolate_attribute.h"
#include "src/tint/ast/module.h"
#include "src/tint/ast/variable_decl_statement.h"
#include "src/tint/constant/value.h"
#include "src/tint/sem/call.h"
#include "src/tint/sem/function.h"
#include "src/tint/sem/member_accessor_expression.h"
#include "src/tint/sem/module.h"
#include "src/tint/sem/struct.h"
#include "src/tint/sem/switch_statement.h"
#include "src/tint/sem/value_constructor.h"
#include "src/tint/sem/value_conversion.h"
#include "src/tint/sem/variable.h"
#include "src/tint/switch.h"
#include "src/tint/transform/array_length_from_uniform.h"
#include "src/tint/transform/binding_remapper.h"
#include "src/tint/transform/builtin_polyfill.h"
#include "src/tint/transform/canonicalize_entry_point_io.h"
#include "src/tint/transform/demote_to_helper.h"
#include "src/tint/transform/disable_uniformity_analysis.h"
#include "src/tint/transform/expand_compound_assignment.h"
#include "src/tint/transform/manager.h"
#include "src/tint/transform/module_scope_var_to_entry_point_param.h"
#include "src/tint/transform/multiplanar_external_texture.h"
#include "src/tint/transform/packed_vec3.h"
#include "src/tint/transform/preserve_padding.h"
#include "src/tint/transform/promote_initializers_to_let.h"
#include "src/tint/transform/promote_side_effects_to_decl.h"
#include "src/tint/transform/remove_phonies.h"
#include "src/tint/transform/robustness.h"
#include "src/tint/transform/simplify_pointers.h"
#include "src/tint/transform/unshadow.h"
#include "src/tint/transform/vectorize_scalar_matrix_initializers.h"
#include "src/tint/transform/zero_init_workgroup_memory.h"
#include "src/tint/type/array.h"
#include "src/tint/type/atomic.h"
#include "src/tint/type/bool.h"
#include "src/tint/type/depth_multisampled_texture.h"
#include "src/tint/type/depth_texture.h"
#include "src/tint/type/f16.h"
#include "src/tint/type/f32.h"
#include "src/tint/type/i32.h"
#include "src/tint/type/matrix.h"
#include "src/tint/type/multisampled_texture.h"
#include "src/tint/type/pointer.h"
#include "src/tint/type/reference.h"
#include "src/tint/type/sampled_texture.h"
#include "src/tint/type/storage_texture.h"
#include "src/tint/type/texture_dimension.h"
#include "src/tint/type/u32.h"
#include "src/tint/type/vector.h"
#include "src/tint/type/void.h"
#include "src/tint/utils/defer.h"
#include "src/tint/utils/map.h"
#include "src/tint/utils/scoped_assignment.h"
#include "src/tint/utils/string_stream.h"
#include "src/tint/writer/check_supported_extensions.h"
#include "src/tint/writer/float_to_string.h"
namespace tint::writer::msl {
namespace {
bool last_is_break(const ast::BlockStatement* stmts) {
return IsAnyOf<ast::BreakStatement>(stmts->Last());
}
void PrintF32(utils::StringStream& out, float value) {
// Note: Currently inf and nan should not be constructable, but this is implemented for the day
// we support them.
if (std::isinf(value)) {
out << (value >= 0 ? "INFINITY" : "-INFINITY");
} else if (std::isnan(value)) {
out << "NAN";
} else {
out << FloatToString(value) << "f";
}
}
void PrintF16(utils::StringStream& out, float value) {
// Note: Currently inf and nan should not be constructable, but this is implemented for the day
// we support them.
if (std::isinf(value)) {
// HUGE_VALH evaluates to +infinity.
out << (value >= 0 ? "HUGE_VALH" : "-HUGE_VALH");
} else if (std::isnan(value)) {
// There is no NaN expr for half in MSL, "NAN" is of float type.
out << "NAN";
} else {
out << FloatToString(value) << "h";
}
}
void PrintI32(utils::StringStream& out, int32_t value) {
// MSL (and C++) parse `-2147483648` as a `long` because it parses unary minus and `2147483648`
// as separate tokens, and the latter doesn't fit into an (32-bit) `int`.
// WGSL, on the other hand, parses this as an `i32`.
// To avoid issues with `long` to `int` casts, emit `(-2147483647 - 1)` instead, which ensures
// the expression type is `int`.
if (auto int_min = std::numeric_limits<int32_t>::min(); value == int_min) {
out << "(" << int_min + 1 << " - 1)";
} else {
out << value;
}
}
class ScopedBitCast {
public:
ScopedBitCast(GeneratorImpl* generator,
utils::StringStream& stream,
const type::Type* curr_type,
const type::Type* target_type)
: s(stream) {
auto* target_vec_type = target_type->As<type::Vector>();
// If we need to promote from scalar to vector, bitcast the scalar to the
// vector element type.
if (curr_type->is_scalar() && target_vec_type) {
target_type = target_vec_type->type();
}
// Bit cast
s << "as_type<";
generator->EmitType(s, target_type, "");
s << ">(";
}
~ScopedBitCast() { s << ")"; }
private:
utils::StringStream& s;
};
} // namespace
SanitizedResult::SanitizedResult() = default;
SanitizedResult::~SanitizedResult() = default;
SanitizedResult::SanitizedResult(SanitizedResult&&) = default;
SanitizedResult Sanitize(const Program* in, const Options& options) {
transform::Manager manager;
transform::DataMap data;
manager.Add<transform::DisableUniformityAnalysis>();
// ExpandCompoundAssignment must come before BuiltinPolyfill
manager.Add<transform::ExpandCompoundAssignment>();
// Build the configs for the internal CanonicalizeEntryPointIO transform.
auto entry_point_io_cfg = transform::CanonicalizeEntryPointIO::Config(
transform::CanonicalizeEntryPointIO::ShaderStyle::kMsl, options.fixed_sample_mask,
options.emit_vertex_point_size);
manager.Add<transform::PreservePadding>();
manager.Add<transform::Unshadow>();
manager.Add<transform::PromoteSideEffectsToDecl>();
if (!options.disable_robustness) {
// Robustness must come after PromoteSideEffectsToDecl
// Robustness must come before BuiltinPolyfill and CanonicalizeEntryPointIO
// Robustness must come before ArrayLengthFromUniform
manager.Add<transform::Robustness>();
}
{ // Builtin polyfills
transform::BuiltinPolyfill::Builtins polyfills;
polyfills.acosh = transform::BuiltinPolyfill::Level::kRangeCheck;
polyfills.atanh = transform::BuiltinPolyfill::Level::kRangeCheck;
polyfills.bitshift_modulo = true; // crbug.com/tint/1543
polyfills.clamp_int = true;
polyfills.conv_f32_to_iu32 = true;
polyfills.extract_bits = transform::BuiltinPolyfill::Level::kClampParameters;
polyfills.first_leading_bit = true;
polyfills.first_trailing_bit = true;
polyfills.insert_bits = transform::BuiltinPolyfill::Level::kClampParameters;
polyfills.int_div_mod = true;
polyfills.sign_int = true;
polyfills.texture_sample_base_clamp_to_edge_2d_f32 = true;
polyfills.workgroup_uniform_load = true;
data.Add<transform::BuiltinPolyfill::Config>(polyfills);
manager.Add<transform::BuiltinPolyfill>();
}
if (!options.external_texture_options.bindings_map.empty()) {
// Note: it is more efficient for MultiplanarExternalTexture to come after Robustness
data.Add<transform::MultiplanarExternalTexture::NewBindingPoints>(
options.external_texture_options.bindings_map);
manager.Add<transform::MultiplanarExternalTexture>();
}
// BindingRemapper must come after MultiplanarExternalTexture
manager.Add<transform::BindingRemapper>();
data.Add<transform::BindingRemapper::Remappings>(
options.binding_remapper_options.binding_points,
options.binding_remapper_options.access_controls,
options.binding_remapper_options.allow_collisions);
if (!options.disable_workgroup_init) {
// ZeroInitWorkgroupMemory must come before CanonicalizeEntryPointIO as
// ZeroInitWorkgroupMemory may inject new builtin parameters.
manager.Add<transform::ZeroInitWorkgroupMemory>();
}
// CanonicalizeEntryPointIO must come after Robustness
manager.Add<transform::CanonicalizeEntryPointIO>();
data.Add<transform::CanonicalizeEntryPointIO::Config>(std::move(entry_point_io_cfg));
manager.Add<transform::PromoteInitializersToLet>();
// DemoteToHelper must come after PromoteSideEffectsToDecl and ExpandCompoundAssignment.
// TODO(crbug.com/tint/1752): This is only necessary for Metal versions older than 2.3.
manager.Add<transform::DemoteToHelper>();
manager.Add<transform::VectorizeScalarMatrixInitializers>();
manager.Add<transform::RemovePhonies>();
manager.Add<transform::SimplifyPointers>();
// ArrayLengthFromUniform must come after SimplifyPointers, as
// it assumes that the form of the array length argument is &var.array.
manager.Add<transform::ArrayLengthFromUniform>();
transform::ArrayLengthFromUniform::Config array_length_cfg(
std::move(options.array_length_from_uniform.ubo_binding));
array_length_cfg.bindpoint_to_size_index =
std::move(options.array_length_from_uniform.bindpoint_to_size_index);
data.Add<transform::ArrayLengthFromUniform::Config>(array_length_cfg);
// PackedVec3 must come after ExpandCompoundAssignment.
manager.Add<transform::PackedVec3>();
manager.Add<transform::ModuleScopeVarToEntryPointParam>();
auto out = manager.Run(in, data);
SanitizedResult result;
result.program = std::move(out.program);
if (!result.program.IsValid()) {
return result;
}
if (auto* res = out.data.Get<transform::ArrayLengthFromUniform::Result>()) {
result.used_array_length_from_uniform_indices = std::move(res->used_size_indices);
}
result.needs_storage_buffer_sizes = !result.used_array_length_from_uniform_indices.empty();
return result;
}
GeneratorImpl::GeneratorImpl(const Program* program) : TextGenerator(program) {}
GeneratorImpl::~GeneratorImpl() = default;
bool GeneratorImpl::Generate() {
if (!CheckSupportedExtensions("MSL", program_->AST(), diagnostics_,
utils::Vector{
builtin::Extension::kChromiumDisableUniformityAnalysis,
builtin::Extension::kChromiumExperimentalFullPtrParameters,
builtin::Extension::kChromiumExperimentalPushConstant,
builtin::Extension::kChromiumInternalRelaxedUniformLayout,
builtin::Extension::kF16,
})) {
return false;
}
line() << "#include <metal_stdlib>";
line();
line() << "using namespace metal;";
auto helpers_insertion_point = current_buffer_->lines.size();
auto* mod = builder_.Sem().Module();
for (auto* decl : mod->DependencyOrderedDeclarations()) {
bool ok = Switch(
decl, //
[&](const ast::Struct* str) {
TINT_DEFER(line());
return EmitTypeDecl(TypeOf(str));
},
[&](const ast::Alias*) {
return true; // folded away by the writer
},
[&](const ast::Const*) {
return true; // Constants are embedded at their use
},
[&](const ast::Override*) {
// Override is removed with SubstituteOverride
diagnostics_.add_error(diag::System::Writer,
"override-expressions should have been removed with the "
"SubstituteOverride transform.");
return false;
},
[&](const ast::Function* func) {
TINT_DEFER(line());
if (func->IsEntryPoint()) {
return EmitEntryPointFunction(func);
}
return EmitFunction(func);
},
[&](const ast::DiagnosticDirective*) {
// Do nothing for diagnostic directives in MSL
return true;
},
[&](const ast::Enable*) {
// Do nothing for enabling extension in MSL
return true;
},
[&](const ast::ConstAssert*) {
return true; // Not emitted
},
[&](Default) {
// These are pushed into the entry point by sanitizer transforms.
TINT_ICE(Writer, diagnostics_) << "unhandled type: " << decl->TypeInfo().name;
return false;
});
if (!ok) {
return false;
}
}
if (!invariant_define_name_.empty()) {
// 'invariant' attribute requires MSL 2.1 or higher.
// WGSL can ignore the invariant attribute on pre MSL 2.1 devices.
// See: https://github.com/gpuweb/gpuweb/issues/893#issuecomment-745537465
line(&helpers_) << "#if __METAL_VERSION__ >= 210";
line(&helpers_) << "#define " << invariant_define_name_ << " @invariant";
line(&helpers_) << "#else";
line(&helpers_) << "#define " << invariant_define_name_;
line(&helpers_) << "#endif";
line(&helpers_);
}
if (!helpers_.lines.empty()) {
current_buffer_->Insert("", helpers_insertion_point++, 0);
current_buffer_->Insert(helpers_, helpers_insertion_point++, 0);
}
return true;
}
bool GeneratorImpl::EmitTypeDecl(const type::Type* ty) {
if (auto* str = ty->As<sem::Struct>()) {
if (!EmitStructType(current_buffer_, str)) {
return false;
}
} else {
diagnostics_.add_error(diag::System::Writer,
"unknown alias type: " + ty->FriendlyName(builder_.Symbols()));
return false;
}
return true;
}
bool GeneratorImpl::EmitIndexAccessor(utils::StringStream& out,
const ast::IndexAccessorExpression* expr) {
bool paren_lhs =
!expr->object
->IsAnyOf<ast::AccessorExpression, ast::CallExpression, ast::IdentifierExpression>();
if (paren_lhs) {
out << "(";
}
if (!EmitExpression(out, expr->object)) {
return false;
}
if (paren_lhs) {
out << ")";
}
out << "[";
if (!EmitExpression(out, expr->index)) {
return false;
}
out << "]";
return true;
}
bool GeneratorImpl::EmitBitcast(utils::StringStream& out, const ast::BitcastExpression* expr) {
out << "as_type<";
if (!EmitType(out, TypeOf(expr)->UnwrapRef(), "")) {
return false;
}
out << ">(";
if (!EmitExpression(out, expr->expr)) {
return false;
}
out << ")";
return true;
}
bool GeneratorImpl::EmitAssign(const ast::AssignmentStatement* stmt) {
auto out = line();
if (!EmitExpression(out, stmt->lhs)) {
return false;
}
out << " = ";
if (!EmitExpression(out, stmt->rhs)) {
return false;
}
out << ";";
return true;
}
bool GeneratorImpl::EmitBinary(utils::StringStream& out, const ast::BinaryExpression* expr) {
auto emit_op = [&] {
out << " ";
switch (expr->op) {
case ast::BinaryOp::kAnd:
out << "&";
break;
case ast::BinaryOp::kOr:
out << "|";
break;
case ast::BinaryOp::kXor:
out << "^";
break;
case ast::BinaryOp::kLogicalAnd:
out << "&&";
break;
case ast::BinaryOp::kLogicalOr:
out << "||";
break;
case ast::BinaryOp::kEqual:
out << "==";
break;
case ast::BinaryOp::kNotEqual:
out << "!=";
break;
case ast::BinaryOp::kLessThan:
out << "<";
break;
case ast::BinaryOp::kGreaterThan:
out << ">";
break;
case ast::BinaryOp::kLessThanEqual:
out << "<=";
break;
case ast::BinaryOp::kGreaterThanEqual:
out << ">=";
break;
case ast::BinaryOp::kShiftLeft:
out << "<<";
break;
case ast::BinaryOp::kShiftRight:
// TODO(dsinclair): MSL is based on C++14, and >> in C++14 has
// implementation-defined behaviour for negative LHS. We may have to
// generate extra code to implement WGSL-specified behaviour for
// negative LHS.
out << R"(>>)";
break;
case ast::BinaryOp::kAdd:
out << "+";
break;
case ast::BinaryOp::kSubtract:
out << "-";
break;
case ast::BinaryOp::kMultiply:
out << "*";
break;
case ast::BinaryOp::kDivide:
out << "/";
break;
case ast::BinaryOp::kModulo:
out << "%";
break;
case ast::BinaryOp::kNone:
diagnostics_.add_error(diag::System::Writer, "missing binary operation type");
return false;
}
out << " ";
return true;
};
auto signed_type_of = [&](const type::Type* ty) -> const type::Type* {
if (ty->is_integer_scalar()) {
return builder_.create<type::I32>();
} else if (auto* v = ty->As<type::Vector>()) {
return builder_.create<type::Vector>(builder_.create<type::I32>(), v->Width());
}
return {};
};
auto unsigned_type_of = [&](const type::Type* ty) -> const type::Type* {
if (ty->is_integer_scalar()) {
return builder_.create<type::U32>();
} else if (auto* v = ty->As<type::Vector>()) {
return builder_.create<type::Vector>(builder_.create<type::U32>(), v->Width());
}
return {};
};
auto* lhs_type = TypeOf(expr->lhs)->UnwrapRef();
auto* rhs_type = TypeOf(expr->rhs)->UnwrapRef();
// Handle fmod
if (expr->op == ast::BinaryOp::kModulo && lhs_type->is_float_scalar_or_vector()) {
out << "fmod";
ScopedParen sp(out);
if (!EmitExpression(out, expr->lhs)) {
return false;
}
out << ", ";
if (!EmitExpression(out, expr->rhs)) {
return false;
}
return true;
}
// Handle +/-/* of signed values
if ((expr->IsAdd() || expr->IsSubtract() || expr->IsMultiply()) &&
lhs_type->is_signed_integer_scalar_or_vector() &&
rhs_type->is_signed_integer_scalar_or_vector()) {
// If lhs or rhs is a vector, use that type (support implicit scalar to
// vector promotion)
auto* target_type = lhs_type->Is<type::Vector>()
? lhs_type
: (rhs_type->Is<type::Vector>() ? rhs_type : lhs_type);
// WGSL defines behaviour for signed overflow, MSL does not. For these
// cases, bitcast operands to unsigned, then cast result to signed.
ScopedBitCast outer_int_cast(this, out, target_type, signed_type_of(target_type));
ScopedParen sp(out);
{
ScopedBitCast lhs_uint_cast(this, out, lhs_type, unsigned_type_of(target_type));
if (!EmitExpression(out, expr->lhs)) {
return false;
}
}
if (!emit_op()) {
return false;
}
{
ScopedBitCast rhs_uint_cast(this, out, rhs_type, unsigned_type_of(target_type));
if (!EmitExpression(out, expr->rhs)) {
return false;
}
}
return true;
}
// Handle left bit shifting a signed value
// TODO(crbug.com/tint/1077): This may not be necessary. The MSL spec
// seems to imply that left shifting a signed value is treated the same as
// left shifting an unsigned value, but we need to make sure.
if (expr->IsShiftLeft() && lhs_type->is_signed_integer_scalar_or_vector()) {
// Shift left: discards top bits, so convert first operand to unsigned
// first, then convert result back to signed
ScopedBitCast outer_int_cast(this, out, lhs_type, signed_type_of(lhs_type));
ScopedParen sp(out);
{
ScopedBitCast lhs_uint_cast(this, out, lhs_type, unsigned_type_of(lhs_type));
if (!EmitExpression(out, expr->lhs)) {
return false;
}
}
if (!emit_op()) {
return false;
}
if (!EmitExpression(out, expr->rhs)) {
return false;
}
return true;
}
// Handle '&' and '|' of booleans.
if ((expr->IsAnd() || expr->IsOr()) && lhs_type->Is<type::Bool>()) {
out << "bool";
ScopedParen sp(out);
if (!EmitExpression(out, expr->lhs)) {
return false;
}
if (!emit_op()) {
return false;
}
if (!EmitExpression(out, expr->rhs)) {
return false;
}
return true;
}
// Emit as usual
ScopedParen sp(out);
if (!EmitExpression(out, expr->lhs)) {
return false;
}
if (!emit_op()) {
return false;
}
if (!EmitExpression(out, expr->rhs)) {
return false;
}
return true;
}
bool GeneratorImpl::EmitBreak(const ast::BreakStatement*) {
line() << "break;";
return true;
}
bool GeneratorImpl::EmitBreakIf(const ast::BreakIfStatement* b) {
auto out = line();
out << "if (";
if (!EmitExpression(out, b->condition)) {
return false;
}
out << ") { break; }";
return true;
}
bool GeneratorImpl::EmitCall(utils::StringStream& out, const ast::CallExpression* expr) {
auto* call = program_->Sem().Get<sem::Call>(expr);
auto* target = call->Target();
return Switch(
target, [&](const sem::Function* func) { return EmitFunctionCall(out, call, func); },
[&](const sem::Builtin* builtin) { return EmitBuiltinCall(out, call, builtin); },
[&](const sem::ValueConversion* conv) { return EmitTypeConversion(out, call, conv); },
[&](const sem::ValueConstructor* ctor) { return EmitTypeInitializer(out, call, ctor); },
[&](Default) {
TINT_ICE(Writer, diagnostics_) << "unhandled call target: " << target->TypeInfo().name;
return false;
});
}
bool GeneratorImpl::EmitFunctionCall(utils::StringStream& out,
const sem::Call* call,
const sem::Function* fn) {
out << program_->Symbols().NameFor(fn->Declaration()->name->symbol) << "(";
bool first = true;
for (auto* arg : call->Arguments()) {
if (!first) {
out << ", ";
}
first = false;
if (!EmitExpression(out, arg->Declaration())) {
return false;
}
}
out << ")";
return true;
}
bool GeneratorImpl::EmitBuiltinCall(utils::StringStream& out,
const sem::Call* call,
const sem::Builtin* builtin) {
auto* expr = call->Declaration();
if (builtin->IsAtomic()) {
return EmitAtomicCall(out, expr, builtin);
}
if (builtin->IsTexture()) {
return EmitTextureCall(out, call, builtin);
}
auto name = generate_builtin_name(builtin);
switch (builtin->Type()) {
case builtin::Function::kDot:
return EmitDotCall(out, expr, builtin);
case builtin::Function::kModf:
return EmitModfCall(out, expr, builtin);
case builtin::Function::kFrexp:
return EmitFrexpCall(out, expr, builtin);
case builtin::Function::kDegrees:
return EmitDegreesCall(out, expr, builtin);
case builtin::Function::kRadians:
return EmitRadiansCall(out, expr, builtin);
case builtin::Function::kPack2X16Float:
case builtin::Function::kUnpack2X16Float: {
if (builtin->Type() == builtin::Function::kPack2X16Float) {
out << "as_type<uint>(half2(";
} else {
out << "float2(as_type<half2>(";
}
if (!EmitExpression(out, expr->args[0])) {
return false;
}
out << "))";
return true;
}
case builtin::Function::kQuantizeToF16: {
std::string width = "";
if (auto* vec = builtin->ReturnType()->As<type::Vector>()) {
width = std::to_string(vec->Width());
}
out << "float" << width << "(half" << width << "(";
if (!EmitExpression(out, expr->args[0])) {
return false;
}
out << "))";
return true;
}
// TODO(crbug.com/tint/661): Combine sequential barriers to a single
// instruction.
case builtin::Function::kStorageBarrier: {
out << "threadgroup_barrier(mem_flags::mem_device)";
return true;
}
case builtin::Function::kWorkgroupBarrier: {
out << "threadgroup_barrier(mem_flags::mem_threadgroup)";
return true;
}
case builtin::Function::kLength: {
auto* sem = builder_.Sem().GetVal(expr->args[0]);
if (sem->Type()->UnwrapRef()->is_scalar()) {
// Emulate scalar overload using fabs(x).
name = "fabs";
}
break;
}
case builtin::Function::kDistance: {
auto* sem = builder_.Sem().GetVal(expr->args[0]);
if (sem->Type()->UnwrapRef()->is_scalar()) {
// Emulate scalar overload using fabs(x - y);
out << "fabs";
ScopedParen sp(out);
if (!EmitExpression(out, expr->args[0])) {
return false;
}
out << " - ";
if (!EmitExpression(out, expr->args[1])) {
return false;
}
return true;
}
break;
}
default:
break;
}
if (name.empty()) {
return false;
}
out << name << "(";
bool first = true;
for (auto* arg : expr->args) {
if (!first) {
out << ", ";
}
first = false;
if (!EmitExpression(out, arg)) {
return false;
}
}
out << ")";
return true;
}
bool GeneratorImpl::EmitTypeConversion(utils::StringStream& out,
const sem::Call* call,
const sem::ValueConversion* conv) {
if (!EmitType(out, conv->Target(), "")) {
return false;
}
out << "(";
if (!EmitExpression(out, call->Arguments()[0]->Declaration())) {
return false;
}
out << ")";
return true;
}
bool GeneratorImpl::EmitTypeInitializer(utils::StringStream& out,
const sem::Call* call,
const sem::ValueConstructor* ctor) {
auto* type = ctor->ReturnType();
const char* terminator = ")";
TINT_DEFER(out << terminator);
bool ok = Switch(
type,
[&](const type::Array*) {
if (!EmitType(out, type, "")) {
return false;
}
out << "{";
terminator = "}";
return true;
},
[&](const sem::Struct*) {
out << "{";
terminator = "}";
return true;
},
[&](Default) {
if (!EmitType(out, type, "")) {
return false;
}
out << "(";
return true;
});
if (!ok) {
return false;
}
size_t i = 0;
for (auto* arg : call->Arguments()) {
if (i > 0) {
out << ", ";
}
if (auto* struct_ty = type->As<sem::Struct>()) {
// Emit field designators for structures to account for padding members.
auto* member = struct_ty->Members()[i]->Declaration();
auto name = program_->Symbols().NameFor(member->name->symbol);
out << "." << name << "=";
}
if (!EmitExpression(out, arg->Declaration())) {
return false;
}
i++;
}
return true;
}
bool GeneratorImpl::EmitAtomicCall(utils::StringStream& out,
const ast::CallExpression* expr,
const sem::Builtin* builtin) {
auto call = [&](const std::string& name, bool append_memory_order_relaxed) {
out << name;
{
ScopedParen sp(out);
for (size_t i = 0; i < expr->args.Length(); i++) {
auto* arg = expr->args[i];
if (i > 0) {
out << ", ";
}
if (!EmitExpression(out, arg)) {
return false;
}
}
if (append_memory_order_relaxed) {
out << ", memory_order_relaxed";
}
}
return true;
};
switch (builtin->Type()) {
case builtin::Function::kAtomicLoad:
return call("atomic_load_explicit", true);
case builtin::Function::kAtomicStore:
return call("atomic_store_explicit", true);
case builtin::Function::kAtomicAdd:
return call("atomic_fetch_add_explicit", true);
case builtin::Function::kAtomicSub:
return call("atomic_fetch_sub_explicit", true);
case builtin::Function::kAtomicMax:
return call("atomic_fetch_max_explicit", true);
case builtin::Function::kAtomicMin:
return call("atomic_fetch_min_explicit", true);
case builtin::Function::kAtomicAnd:
return call("atomic_fetch_and_explicit", true);
case builtin::Function::kAtomicOr:
return call("atomic_fetch_or_explicit", true);
case builtin::Function::kAtomicXor:
return call("atomic_fetch_xor_explicit", true);
case builtin::Function::kAtomicExchange:
return call("atomic_exchange_explicit", true);
case builtin::Function::kAtomicCompareExchangeWeak: {
auto* ptr_ty = TypeOf(expr->args[0])->UnwrapRef()->As<type::Pointer>();
auto sc = ptr_ty->AddressSpace();
auto* str = builtin->ReturnType()->As<sem::Struct>();
auto func = utils::GetOrCreate(
atomicCompareExchangeWeak_, ACEWKeyType{{sc, str}}, [&]() -> std::string {
if (!EmitStructType(&helpers_, builtin->ReturnType()->As<sem::Struct>())) {
return "";
}
auto name = UniqueIdentifier("atomicCompareExchangeWeak");
auto& buf = helpers_;
auto* atomic_ty = builtin->Parameters()[0]->Type();
auto* arg_ty = builtin->Parameters()[1]->Type();
{
auto f = line(&buf);
auto str_name = StructName(builtin->ReturnType()->As<sem::Struct>());
f << str_name << " " << name << "(";
if (!EmitTypeAndName(f, atomic_ty, "atomic")) {
return "";
}
f << ", ";
if (!EmitTypeAndName(f, arg_ty, "compare")) {
return "";
}
f << ", ";
if (!EmitTypeAndName(f, arg_ty, "value")) {
return "";
}
f << ") {";
}
buf.IncrementIndent();
TINT_DEFER({
buf.DecrementIndent();
line(&buf) << "}";
line(&buf);
});
{
auto f = line(&buf);
if (!EmitTypeAndName(f, arg_ty, "old_value")) {
return "";
}
f << " = compare;";
}
line(&buf) << "bool exchanged = "
"atomic_compare_exchange_weak_explicit(atomic, "
"&old_value, value, memory_order_relaxed, "
"memory_order_relaxed);";
line(&buf) << "return {old_value, exchanged};";
return name;
});
if (func.empty()) {
return false;
}
return call(func, false);
}
default:
break;
}
TINT_UNREACHABLE(Writer, diagnostics_) << "unsupported atomic builtin: " << builtin->Type();
return false;
}
bool GeneratorImpl::EmitTextureCall(utils::StringStream& out,
const sem::Call* call,
const sem::Builtin* builtin) {
using Usage = sem::ParameterUsage;
auto& signature = builtin->Signature();
auto* expr = call->Declaration();
auto& arguments = call->Arguments();
// Returns the argument with the given usage
auto arg = [&](Usage usage) {
int idx = signature.IndexOf(usage);
return (idx >= 0) ? arguments[static_cast<size_t>(idx)] : nullptr;
};
auto* texture = arg(Usage::kTexture)->Declaration();
if (TINT_UNLIKELY(!texture)) {
TINT_ICE(Writer, diagnostics_) << "missing texture arg";
return false;
}
auto* texture_type = TypeOf(texture)->UnwrapRef()->As<type::Texture>();
// Helper to emit the texture expression, wrapped in parentheses if the
// expression includes an operator with lower precedence than the member
// accessor used for the function calls.
auto texture_expr = [&]() {
bool paren_lhs = !texture->IsAnyOf<ast::AccessorExpression, ast::CallExpression,
ast::IdentifierExpression>();
if (paren_lhs) {
out << "(";
}
if (!EmitExpression(out, texture)) {
return false;
}
if (paren_lhs) {
out << ")";
}
return true;
};
// MSL requires that `lod` is a constant 0 for 1D textures.
bool level_is_constant_zero = texture_type->dim() == type::TextureDimension::k1d;
switch (builtin->Type()) {
case builtin::Function::kTextureDimensions: {
std::vector<const char*> dims;
switch (texture_type->dim()) {
case type::TextureDimension::kNone:
diagnostics_.add_error(diag::System::Writer, "texture dimension is kNone");
return false;
case type::TextureDimension::k1d:
dims = {"width"};
break;
case type::TextureDimension::k2d:
case type::TextureDimension::k2dArray:
case type::TextureDimension::kCube:
case type::TextureDimension::kCubeArray:
dims = {"width", "height"};
break;
case type::TextureDimension::k3d:
dims = {"width", "height", "depth"};
break;
}
auto get_dim = [&](const char* name) {
if (!texture_expr()) {
return false;
}
out << ".get_" << name << "(";
if (level_is_constant_zero) {
out << "0";
} else {
if (auto* level = arg(Usage::kLevel)) {
if (!EmitExpression(out, level->Declaration())) {
return false;
}
}
}
out << ")";
return true;
};
if (dims.size() == 1) {
get_dim(dims[0]);
} else {
EmitType(out, TypeOf(expr)->UnwrapRef(), "");
out << "(";
for (size_t i = 0; i < dims.size(); i++) {
if (i > 0) {
out << ", ";
}
get_dim(dims[i]);
}
out << ")";
}
return true;
}
case builtin::Function::kTextureNumLayers: {
if (!texture_expr()) {
return false;
}
out << ".get_array_size()";
return true;
}
case builtin::Function::kTextureNumLevels: {
if (!texture_expr()) {
return false;
}
out << ".get_num_mip_levels()";
return true;
}
case builtin::Function::kTextureNumSamples: {
if (!texture_expr()) {
return false;
}
out << ".get_num_samples()";
return true;
}
default:
break;
}
if (!texture_expr()) {
return false;
}
bool lod_param_is_named = true;
switch (builtin->Type()) {
case builtin::Function::kTextureSample:
case builtin::Function::kTextureSampleBias:
case builtin::Function::kTextureSampleLevel:
case builtin::Function::kTextureSampleGrad:
out << ".sample(";
break;
case builtin::Function::kTextureSampleCompare:
case builtin::Function::kTextureSampleCompareLevel:
out << ".sample_compare(";
break;
case builtin::Function::kTextureGather:
out << ".gather(";
break;
case builtin::Function::kTextureGatherCompare:
out << ".gather_compare(";
break;
case builtin::Function::kTextureLoad:
out << ".read(";
lod_param_is_named = false;
break;
case builtin::Function::kTextureStore:
out << ".write(";
break;
default:
TINT_UNREACHABLE(Writer, diagnostics_)
<< "Unhandled texture builtin '" << builtin->str() << "'";
return false;
}
bool first_arg = true;
auto maybe_write_comma = [&] {
if (!first_arg) {
out << ", ";
}
first_arg = false;
};
for (auto usage : {Usage::kValue, Usage::kSampler, Usage::kCoords, Usage::kArrayIndex,
Usage::kDepthRef, Usage::kSampleIndex}) {
if (auto* e = arg(usage)) {
maybe_write_comma();
// Cast the coordinates to unsigned integers if necessary.
bool casted = false;
if (usage == Usage::kCoords && e->Type()->UnwrapRef()->is_integer_scalar_or_vector()) {
casted = true;
switch (texture_type->dim()) {
case type::TextureDimension::k1d:
out << "uint(";
break;
case type::TextureDimension::k2d:
case type::TextureDimension::k2dArray:
out << "uint2(";
break;
case type::TextureDimension::k3d:
out << "uint3(";
break;
default:
TINT_ICE(Writer, diagnostics_) << "unhandled texture dimensionality";
break;
}
}
if (!EmitExpression(out, e->Declaration())) {
return false;
}
if (casted) {
out << ")";
}
}
}
if (auto* bias = arg(Usage::kBias)) {
maybe_write_comma();
out << "bias(";
if (!EmitExpression(out, bias->Declaration())) {
return false;
}
out << ")";
}
if (auto* level = arg(Usage::kLevel)) {
maybe_write_comma();
if (lod_param_is_named) {
out << "level(";
}
if (level_is_constant_zero) {
out << "0";
} else {
if (!EmitExpression(out, level->Declaration())) {
return false;
}
}
if (lod_param_is_named) {
out << ")";
}
}
if (builtin->Type() == builtin::Function::kTextureSampleCompareLevel) {
maybe_write_comma();
out << "level(0)";
}
if (auto* ddx = arg(Usage::kDdx)) {
auto dim = texture_type->dim();
switch (dim) {
case type::TextureDimension::k2d:
case type::TextureDimension::k2dArray:
maybe_write_comma();
out << "gradient2d(";
break;
case type::TextureDimension::k3d:
maybe_write_comma();
out << "gradient3d(";
break;
case type::TextureDimension::kCube:
case type::TextureDimension::kCubeArray:
maybe_write_comma();
out << "gradientcube(";
break;
default: {
utils::StringStream err;
err << "MSL does not support gradients for " << dim << " textures";
diagnostics_.add_error(diag::System::Writer, err.str());
return false;
}
}
if (!EmitExpression(out, ddx->Declaration())) {
return false;
}
out << ", ";
if (!EmitExpression(out, arg(Usage::kDdy)->Declaration())) {
return false;
}
out << ")";
}
bool has_offset = false;
if (auto* offset = arg(Usage::kOffset)) {
has_offset = true;
maybe_write_comma();
if (!EmitExpression(out, offset->Declaration())) {
return false;
}
}
if (auto* component = arg(Usage::kComponent)) {
maybe_write_comma();
if (!has_offset) {
// offset argument may need to be provided if we have a component.
switch (texture_type->dim()) {
case type::TextureDimension::k2d:
case type::TextureDimension::k2dArray:
out << "int2(0), ";
break;
default:
break; // Other texture dimensions don't have an offset
}
}
auto c = component->ConstantValue()->ValueAs<AInt>();
switch (c.value) {
case 0:
out << "component::x";
break;
case 1:
out << "component::y";
break;
case 2:
out << "component::z";
break;
case 3:
out << "component::w";
break;
default:
TINT_ICE(Writer, diagnostics_) << "invalid textureGather component: " << c;
break;
}
}
out << ")";
return true;
}
bool GeneratorImpl::EmitDotCall(utils::StringStream& out,
const ast::CallExpression* expr,
const sem::Builtin* builtin) {
auto* vec_ty = builtin->Parameters()[0]->Type()->As<type::Vector>();
std::string fn = "dot";
if (vec_ty->type()->is_integer_scalar()) {
// MSL does not have a builtin for dot() with integer vector types.
// Generate the helper function if it hasn't been created already
fn = utils::GetOrCreate(int_dot_funcs_, vec_ty->Width(), [&]() -> std::string {
TextBuffer b;
TINT_DEFER(helpers_.Append(b));
auto fn_name = UniqueIdentifier("tint_dot" + std::to_string(vec_ty->Width()));
auto v = "vec<T," + std::to_string(vec_ty->Width()) + ">";
line(&b) << "template<typename T>";
line(&b) << "T " << fn_name << "(" << v << " a, " << v << " b) {";
{
auto l = line(&b);
l << " return ";
for (uint32_t i = 0; i < vec_ty->Width(); i++) {
if (i > 0) {
l << " + ";
}
l << "a[" << i << "]*b[" << i << "]";
}
l << ";";
}
line(&b) << "}";
return fn_name;
});
}
out << fn << "(";
if (!EmitExpression(out, expr->args[0])) {
return false;
}
out << ", ";
if (!EmitExpression(out, expr->args[1])) {
return false;
}
out << ")";
return true;
}
bool GeneratorImpl::EmitModfCall(utils::StringStream& out,
const ast::CallExpression* expr,
const sem::Builtin* builtin) {
return CallBuiltinHelper(
out, expr, builtin, [&](TextBuffer* b, const std::vector<std::string>& params) {
auto* ty = builtin->Parameters()[0]->Type();
auto in = params[0];
std::string width;
if (auto* vec = ty->As<type::Vector>()) {
width = std::to_string(vec->Width());
}
// Emit the builtin return type unique to this overload. This does not
// exist in the AST, so it will not be generated in Generate().
if (!EmitStructType(&helpers_, builtin->ReturnType()->As<sem::Struct>())) {
return false;
}
line(b) << StructName(builtin->ReturnType()->As<sem::Struct>()) << " result;";
line(b) << "result.fract = modf(" << in << ", result.whole);";
line(b) << "return result;";
return true;
});
}
bool GeneratorImpl::EmitFrexpCall(utils::StringStream& out,
const ast::CallExpression* expr,
const sem::Builtin* builtin) {
return CallBuiltinHelper(
out, expr, builtin, [&](TextBuffer* b, const std::vector<std::string>& params) {
auto* ty = builtin->Parameters()[0]->Type();
auto in = params[0];
std::string width;
if (auto* vec = ty->As<type::Vector>()) {
width = std::to_string(vec->Width());
}
// Emit the builtin return type unique to this overload. This does not
// exist in the AST, so it will not be generated in Generate().
if (!EmitStructType(&helpers_, builtin->ReturnType()->As<sem::Struct>())) {
return false;
}
line(b) << StructName(builtin->ReturnType()->As<sem::Struct>()) << " result;";
line(b) << "result.fract = frexp(" << in << ", result.exp);";
line(b) << "return result;";
return true;
});
}
bool GeneratorImpl::EmitDegreesCall(utils::StringStream& out,
const ast::CallExpression* expr,
const sem::Builtin* builtin) {
return CallBuiltinHelper(out, expr, builtin,
[&](TextBuffer* b, const std::vector<std::string>& params) {
line(b) << "return " << params[0] << " * " << std::setprecision(20)
<< sem::kRadToDeg << ";";
return true;
});
}
bool GeneratorImpl::EmitRadiansCall(utils::StringStream& out,
const ast::CallExpression* expr,
const sem::Builtin* builtin) {
return CallBuiltinHelper(out, expr, builtin,
[&](TextBuffer* b, const std::vector<std::string>& params) {
line(b) << "return " << params[0] << " * " << std::setprecision(20)
<< sem::kDegToRad << ";";
return true;
});
}
std::string GeneratorImpl::generate_builtin_name(const sem::Builtin* builtin) {
std::string out = "";
switch (builtin->Type()) {
case builtin::Function::kAcos:
case builtin::Function::kAcosh:
case builtin::Function::kAll:
case builtin::Function::kAny:
case builtin::Function::kAsin:
case builtin::Function::kAsinh:
case builtin::Function::kAtanh:
case builtin::Function::kAtan:
case builtin::Function::kAtan2:
case builtin::Function::kCeil:
case builtin::Function::kCos:
case builtin::Function::kCosh:
case builtin::Function::kCross:
case builtin::Function::kDeterminant:
case builtin::Function::kDistance:
case builtin::Function::kDot:
case builtin::Function::kExp:
case builtin::Function::kExp2:
case builtin::Function::kFloor:
case builtin::Function::kFma:
case builtin::Function::kFract:
case builtin::Function::kFrexp:
case builtin::Function::kLength:
case builtin::Function::kLdexp:
case builtin::Function::kLog:
case builtin::Function::kLog2:
case builtin::Function::kMix:
case builtin::Function::kModf:
case builtin::Function::kNormalize:
case builtin::Function::kPow:
case builtin::Function::kReflect:
case builtin::Function::kRefract:
case builtin::Function::kSaturate:
case builtin::Function::kSelect:
case builtin::Function::kSin:
case builtin::Function::kSinh:
case builtin::Function::kSqrt:
case builtin::Function::kStep:
case builtin::Function::kTan:
case builtin::Function::kTanh:
case builtin::Function::kTranspose:
case builtin::Function::kTrunc:
case builtin::Function::kSign:
case builtin::Function::kClamp:
out += builtin->str();
break;
case builtin::Function::kAbs:
if (builtin->ReturnType()->is_float_scalar_or_vector()) {
out += "fabs";
} else {
out += "abs";
}
break;
case builtin::Function::kCountLeadingZeros:
out += "clz";
break;
case builtin::Function::kCountOneBits:
out += "popcount";
break;
case builtin::Function::kCountTrailingZeros:
out += "ctz";
break;
case builtin::Function::kDpdx:
case builtin::Function::kDpdxCoarse:
case builtin::Function::kDpdxFine:
out += "dfdx";
break;
case builtin::Function::kDpdy:
case builtin::Function::kDpdyCoarse:
case builtin::Function::kDpdyFine:
out += "dfdy";
break;
case builtin::Function::kExtractBits:
out += "extract_bits";
break;
case builtin::Function::kInsertBits:
out += "insert_bits";
break;
case builtin::Function::kFwidth:
case builtin::Function::kFwidthCoarse:
case builtin::Function::kFwidthFine:
out += "fwidth";
break;
case builtin::Function::kMax:
if (builtin->ReturnType()->is_float_scalar_or_vector()) {
out += "fmax";
} else {
out += "max";
}
break;
case builtin::Function::kMin:
if (builtin->ReturnType()->is_float_scalar_or_vector()) {
out += "fmin";
} else {
out += "min";
}
break;
case builtin::Function::kFaceForward:
out += "faceforward";
break;
case builtin::Function::kPack4X8Snorm:
out += "pack_float_to_snorm4x8";
break;
case builtin::Function::kPack4X8Unorm:
out += "pack_float_to_unorm4x8";
break;
case builtin::Function::kPack2X16Snorm:
out += "pack_float_to_snorm2x16";
break;
case builtin::Function::kPack2X16Unorm:
out += "pack_float_to_unorm2x16";
break;
case builtin::Function::kReverseBits:
out += "reverse_bits";
break;
case builtin::Function::kRound:
out += "rint";
break;
case builtin::Function::kSmoothstep:
out += "smoothstep";
break;
case builtin::Function::kInverseSqrt:
out += "rsqrt";
break;
case builtin::Function::kUnpack4X8Snorm:
out += "unpack_snorm4x8_to_float";
break;
case builtin::Function::kUnpack4X8Unorm:
out += "unpack_unorm4x8_to_float";
break;
case builtin::Function::kUnpack2X16Snorm:
out += "unpack_snorm2x16_to_float";
break;
case builtin::Function::kUnpack2X16Unorm:
out += "unpack_unorm2x16_to_float";
break;
case builtin::Function::kArrayLength:
diagnostics_.add_error(
diag::System::Writer,
"Unable to translate builtin: " + std::string(builtin->str()) +
"\nDid you forget to pass array_length_from_uniform generator "
"options?");
return "";
default:
diagnostics_.add_error(diag::System::Writer,
"Unknown import method: " + std::string(builtin->str()));
return "";
}
return out;
}
bool GeneratorImpl::EmitCase(const ast::CaseStatement* stmt) {
auto* sem = builder_.Sem().Get<sem::CaseStatement>(stmt);
for (auto* selector : sem->Selectors()) {
auto out = line();
if (selector->IsDefault()) {
out << "default";
} else {
out << "case ";
if (!EmitConstant(out, selector->Value())) {
return false;
}
}
out << ":";
if (selector == sem->Selectors().back()) {
out << " {";
}
}
{
ScopedIndent si(this);
for (auto* s : stmt->body->statements) {
if (!EmitStatement(s)) {
return false;
}
}
if (!last_is_break(stmt->body)) {
line() << "break;";
}
}
line() << "}";
return true;
}
bool GeneratorImpl::EmitContinue(const ast::ContinueStatement*) {
if (!emit_continuing_ || !emit_continuing_()) {
return false;
}
line() << "continue;";
return true;
}
bool GeneratorImpl::EmitZeroValue(utils::StringStream& out, const type::Type* type) {
return Switch(
type,
[&](const type::Bool*) {
out << "false";
return true;
},
[&](const type::F16*) {
out << "0.0h";
return true;
},
[&](const type::F32*) {
out << "0.0f";
return true;
},
[&](const type::I32*) {
out << "0";
return true;
},
[&](const type::U32*) {
out << "0u";
return true;
},
[&](const type::Vector* vec) { //
return EmitZeroValue(out, vec->type());
},
[&](const type::Matrix* mat) {
if (!EmitType(out, mat, "")) {
return false;
}
ScopedParen sp(out);
return EmitZeroValue(out, mat->type());
},
[&](const type::Array*) {
out << "{}";
return true;
},
[&](const sem::Struct*) {
out << "{}";
return true;
},
[&](Default) {
diagnostics_.add_error(
diag::System::Writer,
"Invalid type for zero emission: " + type->FriendlyName(builder_.Symbols()));
return false;
});
}
bool GeneratorImpl::EmitConstant(utils::StringStream& out, const constant::Value* constant) {
return Switch(
constant->Type(), //
[&](const type::Bool*) {
out << (constant->ValueAs<AInt>() ? "true" : "false");
return true;
},
[&](const type::F32*) {
PrintF32(out, constant->ValueAs<f32>());
return true;
},
[&](const type::F16*) {
PrintF16(out, constant->ValueAs<f16>());
return true;
},
[&](const type::I32*) {
PrintI32(out, constant->ValueAs<i32>());
return true;
},
[&](const type::U32*) {
out << constant->ValueAs<AInt>() << "u";
return true;
},
[&](const type::Vector* v) {
if (!EmitType(out, v, "")) {
return false;
}
ScopedParen sp(out);
if (auto* splat = constant->As<constant::Splat>()) {
if (!EmitConstant(out, splat->el)) {
return false;
}
return true;
}
for (size_t i = 0; i < v->Width(); i++) {
if (i > 0) {
out << ", ";
}
if (!EmitConstant(out, constant->Index(i))) {
return false;
}
}
return true;
},
[&](const type::Matrix* m) {
if (!EmitType(out, m, "")) {
return false;
}
ScopedParen sp(out);
for (size_t i = 0; i < m->columns(); i++) {
if (i > 0) {
out << ", ";
}
if (!EmitConstant(out, constant->Index(i))) {
return false;
}
}
return true;
},
[&](const type::Array* a) {
if (!EmitType(out, a, "")) {
return false;
}
out << "{";
TINT_DEFER(out << "}");
if (constant->AllZero()) {
return true;
}
auto count = a->ConstantCount();
if (!count) {
diagnostics_.add_error(diag::System::Writer,
type::Array::kErrExpectedConstantCount);
return false;
}
for (size_t i = 0; i < count; i++) {
if (i > 0) {
out << ", ";
}
if (!EmitConstant(out, constant->Index(i))) {
return false;
}
}
return true;
},
[&](const sem::Struct* s) {
if (!EmitStructType(&helpers_, s)) {
return false;
}
out << StructName(s) << "{";
TINT_DEFER(out << "}");
if (constant->AllZero()) {
return true;
}
auto members = s->Members();
for (size_t i = 0; i < members.Length(); i++) {
if (i > 0) {
out << ", ";
}
out << "." << program_->Symbols().NameFor(members[i]->Name()) << "=";
if (!EmitConstant(out, constant->Index(i))) {
return false;
}
}
return true;
},
[&](Default) {
diagnostics_.add_error(
diag::System::Writer,
"unhandled constant type: " + builder_.FriendlyName(constant->Type()));
return false;
});
}
bool GeneratorImpl::EmitLiteral(utils::StringStream& out, const ast::LiteralExpression* lit) {
return Switch(
lit,
[&](const ast::BoolLiteralExpression* l) {
out << (l->value ? "true" : "false");
return true;
},
[&](const ast::FloatLiteralExpression* l) {
if (l->suffix == ast::FloatLiteralExpression::Suffix::kH) {
PrintF16(out, static_cast<float>(l->value));
} else {
PrintF32(out, static_cast<float>(l->value));
}
return true;
},
[&](const ast::IntLiteralExpression* i) {
switch (i->suffix) {
case ast::IntLiteralExpression::Suffix::kNone:
case ast::IntLiteralExpression::Suffix::kI: {
PrintI32(out, static_cast<int32_t>(i->value));
return true;
}
case ast::IntLiteralExpression::Suffix::kU: {
out << i->value << "u";
return true;
}
}
diagnostics_.add_error(diag::System::Writer, "unknown integer literal suffix type");
return false;
},
[&](Default) {
diagnostics_.add_error(diag::System::Writer, "unknown literal type");
return false;
});
}
bool GeneratorImpl::EmitExpression(utils::StringStream& out, const ast::Expression* expr) {
if (auto* sem = builder_.Sem().GetVal(expr)) {
if (auto* constant = sem->ConstantValue()) {
return EmitConstant(out, constant);
}
}
return Switch(
expr, //
[&](const ast::IndexAccessorExpression* a) { return EmitIndexAccessor(out, a); },
[&](const ast::BinaryExpression* b) { return EmitBinary(out, b); },
[&](const ast::BitcastExpression* b) { return EmitBitcast(out, b); },
[&](const ast::CallExpression* c) { return EmitCall(out, c); },
[&](const ast::IdentifierExpression* i) { return EmitIdentifier(out, i); },
[&](const ast::LiteralExpression* l) { return EmitLiteral(out, l); },
[&](const ast::MemberAccessorExpression* m) { return EmitMemberAccessor(out, m); },
[&](const ast::UnaryOpExpression* u) { return EmitUnaryOp(out, u); },
[&](Default) { //
diagnostics_.add_error(diag::System::Writer, "unknown expression type: " +
std::string(expr->TypeInfo().name));
return false;
});
}
void GeneratorImpl::EmitStage(utils::StringStream& out, ast::PipelineStage stage) {
switch (stage) {
case ast::PipelineStage::kFragment:
out << "fragment";
break;
case ast::PipelineStage::kVertex:
out << "vertex";
break;
case ast::PipelineStage::kCompute:
out << "kernel";
break;
case ast::PipelineStage::kNone:
break;
}
return;
}
bool GeneratorImpl::EmitFunction(const ast::Function* func) {
auto* func_sem = program_->Sem().Get(func);
{
auto out = line();
if (!EmitType(out, func_sem->ReturnType(), "")) {
return false;
}
out << " " << program_->Symbols().NameFor(func->name->symbol) << "(";
bool first = true;
for (auto* v : func->params) {
if (!first) {
out << ", ";
}
first = false;
auto* type = program_->Sem().Get(v)->Type();
std::string param_name = "const " + program_->Symbols().NameFor(v->name->symbol);
if (!EmitType(out, type, param_name)) {
return false;
}
// Parameter name is output as part of the type for pointers.
if (!type->Is<type::Pointer>()) {
out << " " << program_->Symbols().NameFor(v->name->symbol);
}
}
out << ") {";
}
if (!EmitStatementsWithIndent(func->body->statements)) {
return false;
}
line() << "}";
return true;
}
std::string GeneratorImpl::builtin_to_attribute(builtin::BuiltinValue builtin) const {
switch (builtin) {
case builtin::BuiltinValue::kPosition:
return "position";
case builtin::BuiltinValue::kVertexIndex:
return "vertex_id";
case builtin::BuiltinValue::kInstanceIndex:
return "instance_id";
case builtin::BuiltinValue::kFrontFacing:
return "front_facing";
case builtin::BuiltinValue::kFragDepth:
return "depth(any)";
case builtin::BuiltinValue::kLocalInvocationId:
return "thread_position_in_threadgroup";
case builtin::BuiltinValue::kLocalInvocationIndex:
return "thread_index_in_threadgroup";
case builtin::BuiltinValue::kGlobalInvocationId:
return "thread_position_in_grid";
case builtin::BuiltinValue::kWorkgroupId:
return "threadgroup_position_in_grid";
case builtin::BuiltinValue::kNumWorkgroups:
return "threadgroups_per_grid";
case builtin::BuiltinValue::kSampleIndex:
return "sample_id";
case builtin::BuiltinValue::kSampleMask:
return "sample_mask";
case builtin::BuiltinValue::kPointSize:
return "point_size";
default:
break;
}
return "";
}
std::string GeneratorImpl::interpolation_to_attribute(
builtin::InterpolationType type,
builtin::InterpolationSampling sampling) const {
std::string attr;
switch (sampling) {
case builtin::InterpolationSampling::kCenter:
attr = "center_";
break;
case builtin::InterpolationSampling::kCentroid:
attr = "centroid_";
break;
case builtin::InterpolationSampling::kSample:
attr = "sample_";
break;
case builtin::InterpolationSampling::kUndefined:
break;
}
switch (type) {
case builtin::InterpolationType::kPerspective:
attr += "perspective";
break;
case builtin::InterpolationType::kLinear:
attr += "no_perspective";
break;
case builtin::InterpolationType::kFlat:
attr += "flat";
break;
case builtin::InterpolationType::kUndefined:
break;
}
return attr;
}
bool GeneratorImpl::EmitEntryPointFunction(const ast::Function* func) {
auto* func_sem = builder_.Sem().Get(func);
auto func_name = program_->Symbols().NameFor(func->name->symbol);
// Returns the binding index of a variable, requiring that the group
// attribute have a value of zero.
const uint32_t kInvalidBindingIndex = std::numeric_limits<uint32_t>::max();
auto get_binding_index = [&](const ast::Parameter* param) -> uint32_t {
if (TINT_UNLIKELY(!param->HasBindingPoint())) {
TINT_ICE(Writer, diagnostics_)
<< "missing binding attributes for entry point parameter";
return kInvalidBindingIndex;
}
auto* param_sem = program_->Sem().Get<sem::Parameter>(param);
auto bp = param_sem->BindingPoint();
if (TINT_UNLIKELY(bp.group != 0)) {
TINT_ICE(Writer, diagnostics_) << "encountered non-zero resource group index (use "
"BindingRemapper to fix)";
return kInvalidBindingIndex;
}
return bp.binding;
};
{
auto out = line();
EmitStage(out, func->PipelineStage());
out << " ";
if (!EmitTypeAndName(out, func_sem->ReturnType(), func_name)) {
return false;
}
out << "(";
// Emit entry point parameters.
bool first = true;
for (auto* param : func->params) {
if (!first) {
out << ", ";
}
first = false;
auto* type = program_->Sem().Get(param)->Type()->UnwrapRef();
auto param_name = program_->Symbols().NameFor(param->name->symbol);
if (!EmitType(out, type, param_name)) {
return false;
}
// Parameter name is output as part of the type for pointers.
if (!type->Is<type::Pointer>()) {
out << " " << param_name;
}
bool ok = Switch(
type, //
[&](const type::Struct*) {
out << " [[stage_in]]";
return true;
},
[&](const type::Texture*) {
uint32_t binding = get_binding_index(param);
if (binding == kInvalidBindingIndex) {
return false;
}
out << " [[texture(" << binding << ")]]";
return true;
},
[&](const type::Sampler*) {
uint32_t binding = get_binding_index(param);
if (binding == kInvalidBindingIndex) {
return false;
}
out << " [[sampler(" << binding << ")]]";
return true;
},
[&](const type::Pointer* ptr) {
switch (ptr->AddressSpace()) {
case builtin::AddressSpace::kWorkgroup: {
auto& allocations = workgroup_allocations_[func_name];
out << " [[threadgroup(" << allocations.size() << ")]]";
allocations.push_back(ptr->StoreType()->Size());
return true;
}
case builtin::AddressSpace::kStorage:
case builtin::AddressSpace::kUniform: {
uint32_t binding = get_binding_index(param);
if (binding == kInvalidBindingIndex) {
return false;
}
out << " [[buffer(" << binding << ")]]";
return true;
}
default:
break;
}
TINT_ICE(Writer, diagnostics_)
<< "invalid pointer address space for entry point parameter";
return false;
},
[&](Default) {
auto& attrs = param->attributes;
bool builtin_found = false;
for (auto* attr : attrs) {
auto* builtin_attr = attr->As<ast::BuiltinAttribute>();
if (!builtin_attr) {
continue;
}
auto builtin = program_->Sem().Get(builtin_attr)->Value();
builtin_found = true;
auto name = builtin_to_attribute(builtin);
if (name.empty()) {
diagnostics_.add_error(diag::System::Writer, "unknown builtin");
return false;
}
out << " [[" << name << "]]";
}
if (TINT_UNLIKELY(!builtin_found)) {
TINT_ICE(Writer, diagnostics_) << "Unsupported entry point parameter";
return false;
}
return true;
});
if (!ok) {
return false;
}
}
out << ") {";
}
{
ScopedIndent si(this);
if (!EmitStatements(func->body->statements)) {
return false;
}
if (!Is<ast::ReturnStatement>(func->body->Last())) {
ast::ReturnStatement ret(ProgramID{}, ast::NodeID{}, Source{});
if (!EmitStatement(&ret)) {
return false;
}
}
}
line() << "}";
return true;
}
bool GeneratorImpl::EmitIdentifier(utils::StringStream& out,
const ast::IdentifierExpression* expr) {
out << program_->Symbols().NameFor(expr->identifier->symbol);
return true;
}
bool GeneratorImpl::EmitLoop(const ast::LoopStatement* stmt) {
auto emit_continuing = [this, stmt]() {
if (stmt->continuing && !stmt->continuing->Empty()) {
if (!EmitBlock(stmt->continuing)) {
return false;
}
}
return true;
};
TINT_SCOPED_ASSIGNMENT(emit_continuing_, emit_continuing);
line() << "while (true) {";
{
ScopedIndent si(this);
if (!EmitStatements(stmt->body->statements)) {
return false;
}
if (!emit_continuing_()) {
return false;
}
}
line() << "}";
return true;
}
bool GeneratorImpl::EmitForLoop(const ast::ForLoopStatement* stmt) {
TextBuffer init_buf;
if (auto* init = stmt->initializer) {
TINT_SCOPED_ASSIGNMENT(current_buffer_, &init_buf);
if (!EmitStatement(init)) {
return false;
}
}
TextBuffer cond_pre;
utils::StringStream cond_buf;
if (auto* cond = stmt->condition) {
TINT_SCOPED_ASSIGNMENT(current_buffer_, &cond_pre);
if (!EmitExpression(cond_buf, cond)) {
return false;
}
}
TextBuffer cont_buf;
if (auto* cont = stmt->continuing) {
TINT_SCOPED_ASSIGNMENT(current_buffer_, &cont_buf);
if (!EmitStatement(cont)) {
return false;
}
}
// If the for-loop has a multi-statement conditional and / or continuing,
// then we cannot emit this as a regular for-loop in MSL. Instead we need to
// generate a `while(true)` loop.
bool emit_as_loop = cond_pre.lines.size() > 0 || cont_buf.lines.size() > 1;
// If the for-loop has multi-statement initializer, or is going to be
// emitted as a `while(true)` loop, then declare the initializer
// statement(s) before the loop in a new block.
bool nest_in_block = init_buf.lines.size() > 1 || (stmt->initializer && emit_as_loop);
if (nest_in_block) {
line() << "{";
increment_indent();
current_buffer_->Append(init_buf);
init_buf.lines.clear(); // Don't emit the initializer again in the 'for'
}
TINT_DEFER({
if (nest_in_block) {
decrement_indent();
line() << "}";
}
});
if (emit_as_loop) {
auto emit_continuing = [&]() {
current_buffer_->Append(cont_buf);
return true;
};
TINT_SCOPED_ASSIGNMENT(emit_continuing_, emit_continuing);
line() << "while (true) {";
increment_indent();
TINT_DEFER({
decrement_indent();
line() << "}";
});
if (stmt->condition) {
current_buffer_->Append(cond_pre);
line() << "if (!(" << cond_buf.str() << ")) { break; }";
}
if (!EmitStatements(stmt->body->statements)) {
return false;
}
if (!emit_continuing_()) {
return false;
}
} else {
// For-loop can be generated.
{
auto out = line();
out << "for";
{
ScopedParen sp(out);
if (!init_buf.lines.empty()) {
out << init_buf.lines[0].content << " ";
} else {
out << "; ";
}
out << cond_buf.str() << "; ";
if (!cont_buf.lines.empty()) {
out << TrimSuffix(cont_buf.lines[0].content, ";");
}
}
out << " {";
}
{
auto emit_continuing = [] { return true; };
TINT_SCOPED_ASSIGNMENT(emit_continuing_, emit_continuing);
if (!EmitStatementsWithIndent(stmt->body->statements)) {
return false;
}
}
line() << "}";
}
return true;
}
bool GeneratorImpl::EmitWhile(const ast::WhileStatement* stmt) {
TextBuffer cond_pre;
utils::StringStream cond_buf;
{
auto* cond = stmt->condition;
TINT_SCOPED_ASSIGNMENT(current_buffer_, &cond_pre);
if (!EmitExpression(cond_buf, cond)) {
return false;
}
}
auto emit_continuing = [&]() { return true; };
TINT_SCOPED_ASSIGNMENT(emit_continuing_, emit_continuing);
// If the while has a multi-statement conditional, then we cannot emit this
// as a regular while in MSL. Instead we need to generate a `while(true)` loop.
bool emit_as_loop = cond_pre.lines.size() > 0;
if (emit_as_loop) {
line() << "while (true) {";
increment_indent();
TINT_DEFER({
decrement_indent();
line() << "}";
});
current_buffer_->Append(cond_pre);
line() << "if (!(" << cond_buf.str() << ")) { break; }";
if (!EmitStatements(stmt->body->statements)) {
return false;
}
} else {
// While can be generated.
{
auto out = line();
out << "while";
{
ScopedParen sp(out);
out << cond_buf.str();
}
out << " {";
}
if (!EmitStatementsWithIndent(stmt->body->statements)) {
return false;
}
line() << "}";
}
return true;
}
bool GeneratorImpl::EmitDiscard(const ast::DiscardStatement*) {
// TODO(dsinclair): Verify this is correct when the discard semantics are
// defined for WGSL (https://github.com/gpuweb/gpuweb/issues/361)
line() << "discard_fragment();";
return true;
}
bool GeneratorImpl::EmitIf(const ast::IfStatement* stmt) {
{
auto out = line();
out << "if (";
if (!EmitExpression(out, stmt->condition)) {
return false;
}
out << ") {";
}
if (!EmitStatementsWithIndent(stmt->body->statements)) {
return false;
}
if (stmt->else_statement) {
line() << "} else {";
if (auto* block = stmt->else_statement->As<ast::BlockStatement>()) {
if (!EmitStatementsWithIndent(block->statements)) {
return false;
}
} else {
if (!EmitStatementsWithIndent(utils::Vector{stmt->else_statement})) {
return false;
}
}
}
line() << "}";
return true;
}
bool GeneratorImpl::EmitMemberAccessor(utils::StringStream& out,
const ast::MemberAccessorExpression* expr) {
auto write_lhs = [&] {
bool paren_lhs = !expr->object->IsAnyOf<ast::AccessorExpression, ast::CallExpression,
ast::IdentifierExpression>();
if (paren_lhs) {
out << "(";
}
if (!EmitExpression(out, expr->object)) {
return false;
}
if (paren_lhs) {
out << ")";
}
return true;
};
auto* sem = builder_.Sem().Get(expr)->UnwrapLoad();
return Switch(
sem,
[&](const sem::Swizzle* swizzle) {
// Metal did not add support for swizzle syntax with packed vector types until
// Metal 2.1, so we need to use the index operator for single-element selection instead.
// For multi-component swizzles, the PackedVec3 transform will have inserted casts to
// the non-packed types, so we can safely use swizzle syntax here.
if (swizzle->Indices().Length() == 1) {
if (!write_lhs()) {
return false;
}
out << "[" << swizzle->Indices()[0] << "]";
} else {
if (!write_lhs()) {
return false;
}
out << "." << program_->Symbols().NameFor(expr->member->symbol);
}
return true;
},
[&](const sem::StructMemberAccess* member_access) {
if (!write_lhs()) {
return false;
}
out << "." << program_->Symbols().NameFor(member_access->Member()->Name());
return true;
},
[&](Default) {
TINT_ICE(Writer, diagnostics_)
<< "unknown member access type: " << sem->TypeInfo().name;
return false;
});
}
bool GeneratorImpl::EmitReturn(const ast::ReturnStatement* stmt) {
auto out = line();
out << "return";
if (stmt->value) {
out << " ";
if (!EmitExpression(out, stmt->value)) {
return false;
}
}
out << ";";
return true;
}
bool GeneratorImpl::EmitBlock(const ast::BlockStatement* stmt) {
line() << "{";
if (!EmitStatementsWithIndent(stmt->statements)) {
return false;
}
line() << "}";
return true;
}
bool GeneratorImpl::EmitStatement(const ast::Statement* stmt) {
return Switch(
stmt,
[&](const ast::AssignmentStatement* a) { //
return EmitAssign(a);
},
[&](const ast::BlockStatement* b) { //
return EmitBlock(b);
},
[&](const ast::BreakStatement* b) { //
return EmitBreak(b);
},
[&](const ast::BreakIfStatement* b) { //
return EmitBreakIf(b);
},
[&](const ast::CallStatement* c) { //
auto out = line();
if (!EmitCall(out, c->expr)) { //
return false;
}
out << ";";
return true;
},
[&](const ast::ContinueStatement* c) { //
return EmitContinue(c);
},
[&](const ast::DiscardStatement* d) { //
return EmitDiscard(d);
},
[&](const ast::IfStatement* i) { //
return EmitIf(i);
},
[&](const ast::LoopStatement* l) { //
return EmitLoop(l);
},
[&](const ast::ForLoopStatement* l) { //
return EmitForLoop(l);
},
[&](const ast::WhileStatement* l) { //
return EmitWhile(l);
},
[&](const ast::ReturnStatement* r) { //
return EmitReturn(r);
},
[&](const ast::SwitchStatement* s) { //
return EmitSwitch(s);
},
[&](const ast::VariableDeclStatement* v) { //
return Switch(
v->variable, //
[&](const ast::Var* var) { return EmitVar(var); },
[&](const ast::Let* let) { return EmitLet(let); },
[&](const ast::Const*) {
return true; // Constants are embedded at their use
},
[&](Default) { //
TINT_ICE(Writer, diagnostics_)
<< "unknown statement type: " << stmt->TypeInfo().name;
return false;
});
},
[&](const ast::ConstAssert*) {
return true; // Not emitted
},
[&](Default) {
diagnostics_.add_error(diag::System::Writer,
"unknown statement type: " + std::string(stmt->TypeInfo().name));
return false;
});
}
bool GeneratorImpl::EmitStatements(utils::VectorRef<const ast::Statement*> stmts) {
for (auto* s : stmts) {
if (!EmitStatement(s)) {
return false;
}
}
return true;
}
bool GeneratorImpl::EmitStatementsWithIndent(utils::VectorRef<const ast::Statement*> stmts) {
ScopedIndent si(this);
return EmitStatements(stmts);
}
bool GeneratorImpl::EmitSwitch(const ast::SwitchStatement* stmt) {
{
auto out = line();
out << "switch(";
if (!EmitExpression(out, stmt->condition)) {
return false;
}
out << ") {";
}
{
ScopedIndent si(this);
for (auto* s : stmt->body) {
if (!EmitCase(s)) {
return false;
}
}
}
line() << "}";
return true;
}
bool GeneratorImpl::EmitType(utils::StringStream& out,
const type::Type* type,
const std::string& name,
bool* name_printed /* = nullptr */) {
if (name_printed) {
*name_printed = false;
}
return Switch(
type,
[&](const type::Atomic* atomic) {
if (atomic->Type()->Is<type::I32>()) {
out << "atomic_int";
return true;
}
if (TINT_LIKELY(atomic->Type()->Is<type::U32>())) {
out << "atomic_uint";
return true;
}
TINT_ICE(Writer, diagnostics_)
<< "unhandled atomic type " << atomic->Type()->FriendlyName(builder_.Symbols());
return false;
},
[&](const type::Array* arr) {
out << ArrayType() << "<";
if (!EmitType(out, arr->ElemType(), "")) {
return false;
}
out << ", ";
if (arr->Count()->Is<type::RuntimeArrayCount>()) {
out << "1";
} else {
auto count = arr->ConstantCount();
if (!count) {
diagnostics_.add_error(diag::System::Writer,
type::Array::kErrExpectedConstantCount);
return false;
}
out << count.value();
}
out << ">";
return true;
},
[&](const type::Bool*) {
out << "bool";
return true;
},
[&](const type::F16*) {
out << "half";
return true;
},
[&](const type::F32*) {
out << "float";
return true;
},
[&](const type::I32*) {
out << "int";
return true;
},
[&](const type::Matrix* mat) {
if (!EmitType(out, mat->type(), "")) {
return false;
}
out << mat->columns() << "x" << mat->rows();
return true;
},
[&](const type::Pointer* ptr) {
if (ptr->Access() == builtin::Access::kRead) {
out << "const ";
}
if (!EmitAddressSpace(out, ptr->AddressSpace())) {
return false;
}
out << " ";
if (!EmitType(out, ptr->StoreType(), "")) {
return false;
}
out << "* " << name;
if (name_printed) {
*name_printed = true;
}
return true;
},
[&](const type::Sampler*) {
out << "sampler";
return true;
},
[&](const sem::Struct* str) {
// The struct type emits as just the name. The declaration would be
// emitted as part of emitting the declared types.
out << StructName(str);
return true;
},
[&](const type::Texture* tex) {
if (TINT_UNLIKELY(tex->Is<type::ExternalTexture>())) {
TINT_ICE(Writer, diagnostics_)
<< "Multiplanar external texture transform was not run.";
return false;
}
if (tex->IsAnyOf<type::DepthTexture, type::DepthMultisampledTexture>()) {
out << "depth";
} else {
out << "texture";
}
switch (tex->dim()) {
case type::TextureDimension::k1d:
out << "1d";
break;
case type::TextureDimension::k2d:
out << "2d";
break;
case type::TextureDimension::k2dArray:
out << "2d_array";
break;
case type::TextureDimension::k3d:
out << "3d";
break;
case type::TextureDimension::kCube:
out << "cube";
break;
case type::TextureDimension::kCubeArray:
out << "cube_array";
break;
default:
diagnostics_.add_error(diag::System::Writer, "Invalid texture dimensions");
return false;
}
if (tex->IsAnyOf<type::MultisampledTexture, type::DepthMultisampledTexture>()) {
out << "_ms";
}
out << "<";
TINT_DEFER(out << ">");
return Switch(
tex,
[&](const type::DepthTexture*) {
out << "float, access::sample";
return true;
},
[&](const type::DepthMultisampledTexture*) {
out << "float, access::read";
return true;
},
[&](const type::StorageTexture* storage) {
if (!EmitType(out, storage->type(), "")) {
return false;
}
std::string access_str;
if (storage->access() == builtin::Access::kRead) {
out << ", access::read";
} else if (storage->access() == builtin::Access::kWrite) {
out << ", access::write";
} else {
diagnostics_.add_error(diag::System::Writer,
"Invalid access control for storage texture");
return false;
}
return true;
},
[&](const type::MultisampledTexture* ms) {
if (!EmitType(out, ms->type(), "")) {
return false;
}
out << ", access::read";
return true;
},
[&](const type::SampledTexture* sampled) {
if (!EmitType(out, sampled->type(), "")) {
return false;
}
out << ", access::sample";
return true;
},
[&](Default) {
diagnostics_.add_error(diag::System::Writer, "invalid texture type");
return false;
});
},
[&](const type::U32*) {
out << "uint";
return true;
},
[&](const type::Vector* vec) {
if (vec->Packed()) {
out << "packed_";
}
if (!EmitType(out, vec->type(), "")) {
return false;
}
out << vec->Width();
return true;
},
[&](const type::Void*) {
out << "void";
return true;
},
[&](Default) {
diagnostics_.add_error(
diag::System::Writer,
"unknown type in EmitType: " + type->FriendlyName(builder_.Symbols()));
return false;
});
}
bool GeneratorImpl::EmitTypeAndName(utils::StringStream& out,
const type::Type* type,
const std::string& name) {
bool name_printed = false;
if (!EmitType(out, type, name, &name_printed)) {
return false;
}
if (!name_printed) {
out << " " << name;
}
return true;
}
bool GeneratorImpl::EmitAddressSpace(utils::StringStream& out, builtin::AddressSpace sc) {
switch (sc) {
case builtin::AddressSpace::kFunction:
case builtin::AddressSpace::kPrivate:
case builtin::AddressSpace::kHandle:
out << "thread";
return true;
case builtin::AddressSpace::kWorkgroup:
out << "threadgroup";
return true;
case builtin::AddressSpace::kStorage:
out << "device";
return true;
case builtin::AddressSpace::kUniform:
out << "constant";
return true;
default:
break;
}
TINT_ICE(Writer, diagnostics_) << "unhandled address space: " << sc;
return false;
}
bool GeneratorImpl::EmitStructType(TextBuffer* b, const sem::Struct* str) {
auto it = emitted_structs_.emplace(str);
if (!it.second) {
return true;
}
line(b) << "struct " << StructName(str) << " {";
bool is_host_shareable = str->IsHostShareable();
// Emits a `/* 0xnnnn */` byte offset comment for a struct member.
auto add_byte_offset_comment = [&](utils::StringStream& out, uint32_t offset) {
std::ios_base::fmtflags saved_flag_state(out.flags());
out << "/* 0x" << std::hex << std::setfill('0') << std::setw(4) << offset << " */ ";
out.flags(saved_flag_state);
};
auto add_padding = [&](uint32_t size, uint32_t msl_offset) {
std::string name;
do {
name = UniqueIdentifier("tint_pad");
} while (str->FindMember(program_->Symbols().Get(name)));
auto out = line(b);
add_byte_offset_comment(out, msl_offset);
out << ArrayType() << "<int8_t, " << size << "> " << name << ";";
};
b->IncrementIndent();
uint32_t msl_offset = 0;
for (auto* mem : str->Members()) {
auto out = line(b);
auto mem_name = program_->Symbols().NameFor(mem->Name());
auto wgsl_offset = mem->Offset();
if (is_host_shareable) {
if (TINT_UNLIKELY(wgsl_offset < msl_offset)) {
// Unimplementable layout
TINT_ICE(Writer, diagnostics_) << "Structure member WGSL offset (" << wgsl_offset
<< ") is behind MSL offset (" << msl_offset << ")";
return false;
}
// Generate padding if required
if (auto padding = wgsl_offset - msl_offset) {
add_padding(padding, msl_offset);
msl_offset += padding;
}
add_byte_offset_comment(out, msl_offset);
}
if (!EmitType(out, mem->Type(), mem_name)) {
return false;
}
auto* ty = mem->Type();
out << " " << mem_name;
// Emit attributes
if (auto* decl = mem->Declaration()) {
for (auto* attr : decl->attributes) {
bool ok = Switch(
attr,
[&](const ast::BuiltinAttribute* builtin_attr) {
auto builtin = program_->Sem().Get(builtin_attr)->Value();
auto name = builtin_to_attribute(builtin);
if (name.empty()) {
diagnostics_.add_error(diag::System::Writer, "unknown builtin");
return false;
}
out << " [[" << name << "]]";
return true;
},
[&](const ast::LocationAttribute*) {
auto& pipeline_stage_uses = str->PipelineStageUses();
if (TINT_UNLIKELY(pipeline_stage_uses.size() != 1)) {
TINT_ICE(Writer, diagnostics_) << "invalid entry point IO struct uses";
return false;
}
uint32_t loc = mem->Location().value();
if (pipeline_stage_uses.count(type::PipelineStageUsage::kVertexInput)) {
out << " [[attribute(" + std::to_string(loc) + ")]]";
} else if (pipeline_stage_uses.count(
type::PipelineStageUsage::kVertexOutput)) {
out << " [[user(locn" + std::to_string(loc) + ")]]";
} else if (pipeline_stage_uses.count(
type::PipelineStageUsage::kFragmentInput)) {
out << " [[user(locn" + std::to_string(loc) + ")]]";
} else if (TINT_LIKELY(pipeline_stage_uses.count(
type::PipelineStageUsage::kFragmentOutput))) {
out << " [[color(" + std::to_string(loc) + ")]]";
} else {
TINT_ICE(Writer, diagnostics_) << "invalid use of location decoration";
return false;
}
return true;
},
[&](const ast::InterpolateAttribute* interpolate) {
auto& sem = program_->Sem();
auto i_type =
sem.Get<sem::BuiltinEnumExpression<builtin::InterpolationType>>(
interpolate->type)
->Value();
auto i_smpl = builtin::InterpolationSampling::kUndefined;
if (interpolate->sampling) {
i_smpl =
sem.Get<sem::BuiltinEnumExpression<builtin::InterpolationSampling>>(
interpolate->sampling)
->Value();
}
auto name = interpolation_to_attribute(i_type, i_smpl);
if (name.empty()) {
diagnostics_.add_error(diag::System::Writer,
"unknown interpolation attribute");
return false;
}
out << " [[" << name << "]]";
return true;
},
[&](const ast::InvariantAttribute*) {
if (invariant_define_name_.empty()) {
invariant_define_name_ = UniqueIdentifier("TINT_INVARIANT");
}
out << " " << invariant_define_name_;
return true;
},
[&](const ast::StructMemberOffsetAttribute*) { return true; },
[&](const ast::StructMemberAlignAttribute*) { return true; },
[&](const ast::StructMemberSizeAttribute*) { return true; },
[&](Default) {
TINT_ICE(Writer, diagnostics_)
<< "unhandled struct member attribute: " << attr->Name();
return false;
});
if (!ok) {
return false;
}
}
}
out << ";";
if (is_host_shareable) {
// Calculate new MSL offset
auto size_align = MslPackedTypeSizeAndAlign(ty);
if (TINT_UNLIKELY(msl_offset % size_align.align)) {
TINT_ICE(Writer, diagnostics_)
<< "Misaligned MSL structure member " << ty->FriendlyName(program_->Symbols())
<< " " << mem_name;
return false;
}
msl_offset += size_align.size;
}
}
if (is_host_shareable && str->Size() != msl_offset) {
add_padding(str->Size() - msl_offset, msl_offset);
}
b->DecrementIndent();
line(b) << "};";
return true;
}
bool GeneratorImpl::EmitUnaryOp(utils::StringStream& out, const ast::UnaryOpExpression* expr) {
// Handle `-e` when `e` is signed, so that we ensure that if `e` is the
// largest negative value, it returns `e`.
auto* expr_type = TypeOf(expr->expr)->UnwrapRef();
if (expr->op == ast::UnaryOp::kNegation && expr_type->is_signed_integer_scalar_or_vector()) {
auto fn = utils::GetOrCreate(unary_minus_funcs_, expr_type, [&]() -> std::string {
// e.g.:
// int tint_unary_minus(const int v) {
// return (v == -2147483648) ? v : -v;
// }
TextBuffer b;
TINT_DEFER(helpers_.Append(b));
auto fn_name = UniqueIdentifier("tint_unary_minus");
{
auto decl = line(&b);
if (!EmitTypeAndName(decl, expr_type, fn_name)) {
return "";
}
decl << "(const ";
if (!EmitType(decl, expr_type, "")) {
return "";
}
decl << " v) {";
}
{
ScopedIndent si(&b);
const auto largest_negative_value =
std::to_string(std::numeric_limits<int32_t>::min());
line(&b) << "return select(-v, v, v == " << largest_negative_value << ");";
}
line(&b) << "}";
line(&b);
return fn_name;
});
out << fn << "(";
if (!EmitExpression(out, expr->expr)) {
return false;
}
out << ")";
return true;
}
switch (expr->op) {
case ast::UnaryOp::kAddressOf:
out << "&";
break;
case ast::UnaryOp::kComplement:
out << "~";
break;
case ast::UnaryOp::kIndirection:
out << "*";
break;
case ast::UnaryOp::kNot:
out << "!";
break;
case ast::UnaryOp::kNegation:
out << "-";
break;
}
out << "(";
if (!EmitExpression(out, expr->expr)) {
return false;
}
out << ")";
return true;
}
bool GeneratorImpl::EmitVar(const ast::Var* var) {
auto* sem = program_->Sem().Get(var);
auto* type = sem->Type()->UnwrapRef();
auto out = line();
switch (sem->AddressSpace()) {
case builtin::AddressSpace::kFunction:
case builtin::AddressSpace::kHandle:
break;
case builtin::AddressSpace::kPrivate:
out << "thread ";
break;
case builtin::AddressSpace::kWorkgroup:
out << "threadgroup ";
break;
default:
TINT_ICE(Writer, diagnostics_) << "unhandled variable address space";
return false;
}
std::string name = program_->Symbols().NameFor(var->name->symbol);
if (!EmitType(out, type, name)) {
return false;
}
// Variable name is output as part of the type for pointers.
if (!type->Is<type::Pointer>()) {
out << " " << name;
}
if (var->initializer != nullptr) {
out << " = ";
if (!EmitExpression(out, var->initializer)) {
return false;
}
} else if (sem->AddressSpace() == builtin::AddressSpace::kPrivate ||
sem->AddressSpace() == builtin::AddressSpace::kFunction ||
sem->AddressSpace() == builtin::AddressSpace::kUndefined) {
out << " = ";
if (!EmitZeroValue(out, type)) {
return false;
}
}
out << ";";
return true;
}
bool GeneratorImpl::EmitLet(const ast::Let* let) {
auto* sem = program_->Sem().Get(let);
auto* type = sem->Type();
auto out = line();
switch (sem->AddressSpace()) {
case builtin::AddressSpace::kFunction:
case builtin::AddressSpace::kHandle:
case builtin::AddressSpace::kUndefined:
break;
case builtin::AddressSpace::kPrivate:
out << "thread ";
break;
case builtin::AddressSpace::kWorkgroup:
out << "threadgroup ";
break;
default:
TINT_ICE(Writer, diagnostics_) << "unhandled variable address space";
return false;
}
std::string name = "const " + program_->Symbols().NameFor(let->name->symbol);
if (!EmitType(out, type, name)) {
return false;
}
// Variable name is output as part of the type for pointers.
if (!type->Is<type::Pointer>()) {
out << " " << name;
}
out << " = ";
if (!EmitExpression(out, let->initializer)) {
return false;
}
out << ";";
return true;
}
GeneratorImpl::SizeAndAlign GeneratorImpl::MslPackedTypeSizeAndAlign(const type::Type* ty) {
return Switch(
ty,
// https://developer.apple.com/metal/Metal-Shading-Language-Specification.pdf
// 2.1 Scalar Data Types
[&](const type::U32*) {
return SizeAndAlign{4, 4};
},
[&](const type::I32*) {
return SizeAndAlign{4, 4};
},
[&](const type::F32*) {
return SizeAndAlign{4, 4};
},
[&](const type::F16*) {
return SizeAndAlign{2, 2};
},
[&](const type::Vector* vec) {
auto num_els = vec->Width();
auto* el_ty = vec->type();
SizeAndAlign el_size_align = MslPackedTypeSizeAndAlign(el_ty);
if (el_ty->IsAnyOf<type::U32, type::I32, type::F32, type::F16>()) {
// Use a packed_vec type for 3-element vectors only.
if (num_els == 3) {
// https://developer.apple.com/metal/Metal-Shading-Language-Specification.pdf
// 2.2.3 Packed Vector Types
return SizeAndAlign{num_els * el_size_align.size, el_size_align.align};
} else {
// https://developer.apple.com/metal/Metal-Shading-Language-Specification.pdf
// 2.2 Vector Data Types
// Vector data types are aligned to their size.
return SizeAndAlign{num_els * el_size_align.size, num_els * el_size_align.size};
}
}
TINT_UNREACHABLE(Writer, diagnostics_)
<< "Unhandled vector element type " << el_ty->TypeInfo().name;
return SizeAndAlign{};
},
[&](const type::Matrix* mat) {
// https://developer.apple.com/metal/Metal-Shading-Language-Specification.pdf
// 2.3 Matrix Data Types
auto cols = mat->columns();
auto rows = mat->rows();
auto* el_ty = mat->type();
// Metal only support half and float matrix.
if (el_ty->IsAnyOf<type::F32, type::F16>()) {
static constexpr SizeAndAlign table_f32[] = {
/* float2x2 */ {16, 8},
/* float2x3 */ {32, 16},
/* float2x4 */ {32, 16},
/* float3x2 */ {24, 8},
/* float3x3 */ {48, 16},
/* float3x4 */ {48, 16},
/* float4x2 */ {32, 8},
/* float4x3 */ {64, 16},
/* float4x4 */ {64, 16},
};
static constexpr SizeAndAlign table_f16[] = {
/* half2x2 */ {8, 4},
/* half2x3 */ {16, 8},
/* half2x4 */ {16, 8},
/* half3x2 */ {12, 4},
/* half3x3 */ {24, 8},
/* half3x4 */ {24, 8},
/* half4x2 */ {16, 4},
/* half4x3 */ {32, 8},
/* half4x4 */ {32, 8},
};
if (cols >= 2 && cols <= 4 && rows >= 2 && rows <= 4) {
if (el_ty->Is<type::F32>()) {
return table_f32[(3 * (cols - 2)) + (rows - 2)];
} else {
return table_f16[(3 * (cols - 2)) + (rows - 2)];
}
}
}
TINT_UNREACHABLE(Writer, diagnostics_)
<< "Unhandled matrix element type " << el_ty->TypeInfo().name;
return SizeAndAlign{};
},
[&](const type::Array* arr) {
if (TINT_UNLIKELY(!arr->IsStrideImplicit())) {
TINT_ICE(Writer, diagnostics_)
<< "arrays with explicit strides should not exist past the SPIR-V reader";
return SizeAndAlign{};
}
if (arr->Count()->Is<type::RuntimeArrayCount>()) {
return SizeAndAlign{arr->Stride(), arr->Align()};
}
if (auto count = arr->ConstantCount()) {
return SizeAndAlign{arr->Stride() * count.value(), arr->Align()};
}
diagnostics_.add_error(diag::System::Writer, type::Array::kErrExpectedConstantCount);
return SizeAndAlign{};
},
[&](const sem::Struct* str) {
// TODO(crbug.com/tint/650): There's an assumption here that MSL's
// default structure size and alignment matches WGSL's. We need to
// confirm this.
return SizeAndAlign{str->Size(), str->Align()};
},
[&](const type::Atomic* atomic) { return MslPackedTypeSizeAndAlign(atomic->Type()); },
[&](Default) {
TINT_UNREACHABLE(Writer, diagnostics_) << "Unhandled type " << ty->TypeInfo().name;
return SizeAndAlign{};
});
}
template <typename F>
bool GeneratorImpl::CallBuiltinHelper(utils::StringStream& out,
const ast::CallExpression* call,
const sem::Builtin* builtin,
F&& build) {
// Generate the helper function if it hasn't been created already
auto fn = utils::GetOrCreate(builtins_, builtin, [&]() -> std::string {
TextBuffer b;
TINT_DEFER(helpers_.Append(b));
auto fn_name = UniqueIdentifier(std::string("tint_") + builtin::str(builtin->Type()));
std::vector<std::string> parameter_names;
{
auto decl = line(&b);
if (!EmitTypeAndName(decl, builtin->ReturnType(), fn_name)) {
return "";
}
{
ScopedParen sp(decl);
for (auto* param : builtin->Parameters()) {
if (!parameter_names.empty()) {
decl << ", ";
}
auto param_name = "param_" + std::to_string(parameter_names.size());
if (!EmitTypeAndName(decl, param->Type(), param_name)) {
return "";
}
parameter_names.emplace_back(std::move(param_name));
}
}
decl << " {";
}
{
ScopedIndent si(&b);
if (!build(&b, parameter_names)) {
return "";
}
}
line(&b) << "}";
line(&b);
return fn_name;
});
if (fn.empty()) {
return false;
}
// Call the helper
out << fn;
{
ScopedParen sp(out);
bool first = true;
for (auto* arg : call->args) {
if (!first) {
out << ", ";
}
first = false;
if (!EmitExpression(out, arg)) {
return false;
}
}
}
return true;
}
const std::string& GeneratorImpl::ArrayType() {
if (array_template_name_.empty()) {
array_template_name_ = UniqueIdentifier("tint_array");
auto* buf = &helpers_;
line(buf) << "template<typename T, size_t N>";
line(buf) << "struct " << array_template_name_ << " {";
line(buf) << " const constant T& operator[](size_t i) const constant"
<< " { return elements[i]; }";
for (auto* space : {"device", "thread", "threadgroup"}) {
line(buf) << " " << space << " T& operator[](size_t i) " << space
<< " { return elements[i]; }";
line(buf) << " const " << space << " T& operator[](size_t i) const " << space
<< " { return elements[i]; }";
}
line(buf) << " T elements[N];";
line(buf) << "};";
line(buf);
}
return array_template_name_;
}
} // namespace tint::writer::msl