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// Copyright 2020 The Dawn & Tint Authors
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
// list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "src/tint/lang/msl/writer/ast_printer/ast_printer.h"
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <limits>
#include <utility>
#include <vector>
#include "src/tint/lang/core/constant/splat.h"
#include "src/tint/lang/core/constant/value.h"
#include "src/tint/lang/core/fluent_types.h"
#include "src/tint/lang/core/type/array.h"
#include "src/tint/lang/core/type/atomic.h"
#include "src/tint/lang/core/type/bool.h"
#include "src/tint/lang/core/type/depth_multisampled_texture.h"
#include "src/tint/lang/core/type/depth_texture.h"
#include "src/tint/lang/core/type/f16.h"
#include "src/tint/lang/core/type/f32.h"
#include "src/tint/lang/core/type/i32.h"
#include "src/tint/lang/core/type/matrix.h"
#include "src/tint/lang/core/type/multisampled_texture.h"
#include "src/tint/lang/core/type/pointer.h"
#include "src/tint/lang/core/type/reference.h"
#include "src/tint/lang/core/type/sampled_texture.h"
#include "src/tint/lang/core/type/storage_texture.h"
#include "src/tint/lang/core/type/texture_dimension.h"
#include "src/tint/lang/core/type/u32.h"
#include "src/tint/lang/core/type/vector.h"
#include "src/tint/lang/core/type/void.h"
#include "src/tint/lang/msl/writer/ast_raise/module_scope_var_to_entry_point_param.h"
#include "src/tint/lang/msl/writer/ast_raise/packed_vec3.h"
#include "src/tint/lang/msl/writer/ast_raise/pixel_local.h"
#include "src/tint/lang/msl/writer/ast_raise/subgroup_ballot.h"
#include "src/tint/lang/msl/writer/common/option_helpers.h"
#include "src/tint/lang/msl/writer/common/printer_support.h"
#include "src/tint/lang/wgsl/ast/alias.h"
#include "src/tint/lang/wgsl/ast/bool_literal_expression.h"
#include "src/tint/lang/wgsl/ast/call_statement.h"
#include "src/tint/lang/wgsl/ast/disable_validation_attribute.h"
#include "src/tint/lang/wgsl/ast/float_literal_expression.h"
#include "src/tint/lang/wgsl/ast/id_attribute.h"
#include "src/tint/lang/wgsl/ast/interpolate_attribute.h"
#include "src/tint/lang/wgsl/ast/module.h"
#include "src/tint/lang/wgsl/ast/transform/array_length_from_uniform.h"
#include "src/tint/lang/wgsl/ast/transform/binding_remapper.h"
#include "src/tint/lang/wgsl/ast/transform/builtin_polyfill.h"
#include "src/tint/lang/wgsl/ast/transform/canonicalize_entry_point_io.h"
#include "src/tint/lang/wgsl/ast/transform/demote_to_helper.h"
#include "src/tint/lang/wgsl/ast/transform/disable_uniformity_analysis.h"
#include "src/tint/lang/wgsl/ast/transform/expand_compound_assignment.h"
#include "src/tint/lang/wgsl/ast/transform/manager.h"
#include "src/tint/lang/wgsl/ast/transform/multiplanar_external_texture.h"
#include "src/tint/lang/wgsl/ast/transform/preserve_padding.h"
#include "src/tint/lang/wgsl/ast/transform/promote_initializers_to_let.h"
#include "src/tint/lang/wgsl/ast/transform/promote_side_effects_to_decl.h"
#include "src/tint/lang/wgsl/ast/transform/remove_phonies.h"
#include "src/tint/lang/wgsl/ast/transform/robustness.h"
#include "src/tint/lang/wgsl/ast/transform/simplify_pointers.h"
#include "src/tint/lang/wgsl/ast/transform/unshadow.h"
#include "src/tint/lang/wgsl/ast/transform/vectorize_scalar_matrix_initializers.h"
#include "src/tint/lang/wgsl/ast/transform/zero_init_workgroup_memory.h"
#include "src/tint/lang/wgsl/ast/variable_decl_statement.h"
#include "src/tint/lang/wgsl/helpers/check_supported_extensions.h"
#include "src/tint/lang/wgsl/sem/call.h"
#include "src/tint/lang/wgsl/sem/function.h"
#include "src/tint/lang/wgsl/sem/member_accessor_expression.h"
#include "src/tint/lang/wgsl/sem/module.h"
#include "src/tint/lang/wgsl/sem/struct.h"
#include "src/tint/lang/wgsl/sem/switch_statement.h"
#include "src/tint/lang/wgsl/sem/value_constructor.h"
#include "src/tint/lang/wgsl/sem/value_conversion.h"
#include "src/tint/lang/wgsl/sem/variable.h"
#include "src/tint/utils/containers/map.h"
#include "src/tint/utils/macros/defer.h"
#include "src/tint/utils/macros/scoped_assignment.h"
#include "src/tint/utils/rtti/switch.h"
#include "src/tint/utils/text/string_stream.h"
using namespace tint::core::fluent_types; // NOLINT
namespace tint::msl::writer {
namespace {
bool last_is_break(const ast::BlockStatement* stmts) {
return tint::IsAnyOf<ast::BreakStatement>(stmts->Last());
}
class ScopedBitCast {
public:
ScopedBitCast(ASTPrinter* generator,
StringStream& stream,
const core::type::Type* curr_type,
const core::type::Type* target_type)
: s(stream) {
auto* target_vec_type = target_type->As<core::type::Vector>();
// If we need to promote from scalar to vector, bitcast the scalar to the
// vector element type.
if (curr_type->Is<core::type::Scalar>() && target_vec_type) {
target_type = target_vec_type->type();
}
// Bit cast
s << "as_type<";
generator->EmitType(s, target_type);
s << ">(";
}
~ScopedBitCast() { s << ")"; }
private:
StringStream& s;
};
} // namespace
SanitizedResult::SanitizedResult() = default;
SanitizedResult::~SanitizedResult() = default;
SanitizedResult::SanitizedResult(SanitizedResult&&) = default;
SanitizedResult Sanitize(const Program& in, const Options& options) {
ast::transform::Manager manager;
ast::transform::DataMap data;
manager.Add<ast::transform::DisableUniformityAnalysis>();
// ExpandCompoundAssignment must come before BuiltinPolyfill
manager.Add<ast::transform::ExpandCompoundAssignment>();
// Build the configs for the internal CanonicalizeEntryPointIO transform.
auto entry_point_io_cfg = ast::transform::CanonicalizeEntryPointIO::Config(
ast::transform::CanonicalizeEntryPointIO::ShaderStyle::kMsl, options.fixed_sample_mask,
options.emit_vertex_point_size);
manager.Add<ast::transform::PreservePadding>();
manager.Add<ast::transform::Unshadow>();
manager.Add<ast::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<ast::transform::Robustness>();
}
{ // Builtin polyfills
ast::transform::BuiltinPolyfill::Builtins polyfills;
polyfills.acosh = ast::transform::BuiltinPolyfill::Level::kRangeCheck;
polyfills.atanh = ast::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 = ast::transform::BuiltinPolyfill::Level::kClampParameters;
polyfills.first_leading_bit = true;
polyfills.first_trailing_bit = true;
polyfills.insert_bits = ast::transform::BuiltinPolyfill::Level::kClampParameters;
polyfills.int_div_mod = !options.disable_polyfill_integer_div_mod;
polyfills.sign_int = true;
polyfills.texture_sample_base_clamp_to_edge_2d_f32 = true;
polyfills.workgroup_uniform_load = true;
polyfills.pack_unpack_4x8 = true;
polyfills.pack_4xu8_clamp = true;
data.Add<ast::transform::BuiltinPolyfill::Config>(polyfills);
manager.Add<ast::transform::BuiltinPolyfill>();
}
ExternalTextureOptions external_texture_options{};
RemapperData remapper_data{};
PopulateRemapperAndMultiplanarOptions(options, remapper_data, external_texture_options);
manager.Add<ast::transform::BindingRemapper>();
data.Add<ast::transform::BindingRemapper::Remappings>(
remapper_data, std::unordered_map<BindingPoint, core::Access>{},
/* allow_collisions */ true);
// Note: it is more efficient for MultiplanarExternalTexture to come after Robustness
// MultiplanarExternalTexture must come after BindingRemapper
data.Add<ast::transform::MultiplanarExternalTexture::NewBindingPoints>(
external_texture_options.bindings_map, /* allow_collisions */ true);
manager.Add<ast::transform::MultiplanarExternalTexture>();
if (!options.disable_workgroup_init) {
// ZeroInitWorkgroupMemory must come before CanonicalizeEntryPointIO as
// ZeroInitWorkgroupMemory may inject new builtin parameters.
manager.Add<ast::transform::ZeroInitWorkgroupMemory>();
}
{
PixelLocal::Config cfg;
for (auto it : options.pixel_local_options.attachments) {
cfg.attachments.Add(it.first, it.second);
}
data.Add<PixelLocal::Config>(cfg);
manager.Add<PixelLocal>();
}
// CanonicalizeEntryPointIO must come after Robustness
manager.Add<ast::transform::CanonicalizeEntryPointIO>();
data.Add<ast::transform::CanonicalizeEntryPointIO::Config>(std::move(entry_point_io_cfg));
manager.Add<ast::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<ast::transform::DemoteToHelper>();
manager.Add<ast::transform::VectorizeScalarMatrixInitializers>();
manager.Add<ast::transform::RemovePhonies>();
manager.Add<ast::transform::SimplifyPointers>();
// SubgroupBallot() must come after CanonicalizeEntryPointIO.
manager.Add<SubgroupBallot>();
// ArrayLengthFromUniform must come after SimplifyPointers, as
// it assumes that the form of the array length argument is &var.array.
manager.Add<ast::transform::ArrayLengthFromUniform>();
ast::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<ast::transform::ArrayLengthFromUniform::Config>(array_length_cfg);
// PackedVec3 must come after ExpandCompoundAssignment.
manager.Add<PackedVec3>();
manager.Add<ModuleScopeVarToEntryPointParam>();
SanitizedResult result;
ast::transform::DataMap outputs;
result.program = manager.Run(in, data, outputs);
if (!result.program.IsValid()) {
return result;
}
if (auto* res = outputs.Get<ast::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;
}
ASTPrinter::ASTPrinter(const Program& program) : builder_(ProgramBuilder::Wrap(program)) {}
ASTPrinter::~ASTPrinter() = default;
bool ASTPrinter::Generate() {
if (!tint::wgsl::CheckSupportedExtensions(
"MSL", builder_.AST(), diagnostics_,
Vector{
wgsl::Extension::kChromiumDisableUniformityAnalysis,
wgsl::Extension::kChromiumExperimentalFullPtrParameters,
wgsl::Extension::kChromiumExperimentalPixelLocal,
wgsl::Extension::kChromiumExperimentalSubgroups,
wgsl::Extension::kChromiumExperimentalFramebufferFetch,
wgsl::Extension::kChromiumInternalDualSourceBlending,
wgsl::Extension::kChromiumInternalRelaxedUniformLayout,
wgsl::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::Requires*) {
// Do nothing for requiring language features in MSL.
return true;
},
[&](const ast::ConstAssert*) {
return true; // Not emitted
}, //
TINT_ICE_ON_NO_MATCH);
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 ASTPrinter::EmitTypeDecl(const core::type::Type* ty) {
if (auto* str = ty->As<core::type::Struct>()) {
if (!EmitStructType(current_buffer_, str)) {
return false;
}
} else {
diagnostics_.add_error(diag::System::Writer, "unknown alias type: " + ty->FriendlyName());
return false;
}
return true;
}
bool ASTPrinter::EmitIndexAccessor(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 ASTPrinter::EmitBitcast(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 ASTPrinter::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 ASTPrinter::EmitBinary(StringStream& out, const ast::BinaryExpression* expr) {
auto emit_op = [&] {
out << " ";
switch (expr->op) {
case core::BinaryOp::kAnd:
out << "&";
break;
case core::BinaryOp::kOr:
out << "|";
break;
case core::BinaryOp::kXor:
out << "^";
break;
case core::BinaryOp::kLogicalAnd:
out << "&&";
break;
case core::BinaryOp::kLogicalOr:
out << "||";
break;
case core::BinaryOp::kEqual:
out << "==";
break;
case core::BinaryOp::kNotEqual:
out << "!=";
break;
case core::BinaryOp::kLessThan:
out << "<";
break;
case core::BinaryOp::kGreaterThan:
out << ">";
break;
case core::BinaryOp::kLessThanEqual:
out << "<=";
break;
case core::BinaryOp::kGreaterThanEqual:
out << ">=";
break;
case core::BinaryOp::kShiftLeft:
out << "<<";
break;
case core::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 core::BinaryOp::kAdd:
out << "+";
break;
case core::BinaryOp::kSubtract:
out << "-";
break;
case core::BinaryOp::kMultiply:
out << "*";
break;
case core::BinaryOp::kDivide:
out << "/";
break;
case core::BinaryOp::kModulo:
out << "%";
break;
}
out << " ";
return true;
};
auto signed_type_of = [&](const core::type::Type* ty) -> const core::type::Type* {
if (ty->is_integer_scalar()) {
return builder_.create<core::type::I32>();
} else if (auto* v = ty->As<core::type::Vector>()) {
return builder_.create<core::type::Vector>(builder_.create<core::type::I32>(),
v->Width());
}
return {};
};
auto unsigned_type_of = [&](const core::type::Type* ty) -> const core::type::Type* {
if (ty->is_integer_scalar()) {
return builder_.create<core::type::U32>();
} else if (auto* v = ty->As<core::type::Vector>()) {
return builder_.create<core::type::Vector>(builder_.create<core::type::U32>(),
v->Width());
}
return {};
};
auto* lhs_type = TypeOf(expr->lhs)->UnwrapRef();
auto* rhs_type = TypeOf(expr->rhs)->UnwrapRef();
// Handle fmod
if (expr->op == core::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<core::type::Vector>()
? lhs_type
: (rhs_type->Is<core::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<core::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 ASTPrinter::EmitBreak(const ast::BreakStatement*) {
Line() << "break;";
return true;
}
bool ASTPrinter::EmitBreakIf(const ast::BreakIfStatement* b) {
auto out = Line();
out << "if (";
if (!EmitExpression(out, b->condition)) {
return false;
}
out << ") { break; }";
return true;
}
bool ASTPrinter::EmitCall(StringStream& out, const ast::CallExpression* expr) {
auto* call = builder_.Sem().Get<sem::Call>(expr);
auto* target = call->Target();
return Switch(
target, //
[&](const sem::Function* func) { return EmitFunctionCall(out, call, func); },
[&](const sem::BuiltinFn* builtin) { return EmitBuiltinCall(out, call, builtin); },
[&](const sem::ValueConversion* conv) { return EmitTypeConversion(out, call, conv); },
[&](const sem::ValueConstructor* ctor) { return EmitTypeInitializer(out, call, ctor); }, //
TINT_ICE_ON_NO_MATCH);
}
bool ASTPrinter::EmitFunctionCall(StringStream& out,
const sem::Call* call,
const sem::Function* fn) {
if (ast::GetAttribute<SubgroupBallot::SimdActiveThreadsMask>(fn->Declaration()->attributes) !=
nullptr) {
out << "as_type<uint2>((ulong)simd_active_threads_mask())";
return true;
}
out << fn->Declaration()->name->symbol.Name() << "(";
bool first = true;
for (auto* arg : call->Arguments()) {
if (!first) {
out << ", ";
}
first = false;
if (!EmitExpression(out, arg->Declaration())) {
return false;
}
}
out << ")";
return true;
}
bool ASTPrinter::EmitBuiltinCall(StringStream& out,
const sem::Call* call,
const sem::BuiltinFn* 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->Fn()) {
case wgsl::BuiltinFn::kDot:
return EmitDotCall(out, expr, builtin);
case wgsl::BuiltinFn::kModf:
return EmitModfCall(out, expr, builtin);
case wgsl::BuiltinFn::kFrexp:
return EmitFrexpCall(out, expr, builtin);
case wgsl::BuiltinFn::kDegrees:
return EmitDegreesCall(out, expr, builtin);
case wgsl::BuiltinFn::kRadians:
return EmitRadiansCall(out, expr, builtin);
case wgsl::BuiltinFn::kDot4I8Packed:
return EmitDot4I8PackedCall(out, expr, builtin);
case wgsl::BuiltinFn::kDot4U8Packed:
return EmitDot4U8PackedCall(out, expr, builtin);
case wgsl::BuiltinFn::kPack2X16Float:
case wgsl::BuiltinFn::kUnpack2X16Float: {
if (builtin->Fn() == wgsl::BuiltinFn::kPack2X16Float) {
out << "as_type<uint>(half2(";
} else {
out << "float2(as_type<half2>(";
}
if (!EmitExpression(out, expr->args[0])) {
return false;
}
out << "))";
return true;
}
case wgsl::BuiltinFn::kQuantizeToF16: {
std::string width = "";
if (auto* vec = builtin->ReturnType()->As<core::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 wgsl::BuiltinFn::kStorageBarrier: {
out << "threadgroup_barrier(mem_flags::mem_device)";
return true;
}
case wgsl::BuiltinFn::kWorkgroupBarrier: {
out << "threadgroup_barrier(mem_flags::mem_threadgroup)";
return true;
}
case wgsl::BuiltinFn::kTextureBarrier: {
out << "threadgroup_barrier(mem_flags::mem_texture)";
return true;
}
case wgsl::BuiltinFn::kLength: {
auto* sem = builder_.Sem().GetVal(expr->args[0]);
if (sem->Type()->UnwrapRef()->Is<core::type::Scalar>()) {
// Emulate scalar overload using fabs(x).
name = "fabs";
}
break;
}
case wgsl::BuiltinFn::kDistance: {
auto* sem = builder_.Sem().GetVal(expr->args[0]);
if (sem->Type()->UnwrapRef()->Is<core::type::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;
}
case wgsl::BuiltinFn::kSubgroupBroadcast: {
// The lane argument is ushort.
out << "simd_broadcast(";
if (!EmitExpression(out, expr->args[0])) {
return false;
}
out << ",ushort(";
if (!EmitExpression(out, expr->args[1])) {
return false;
}
out << "))";
return true;
}
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 ASTPrinter::EmitTypeConversion(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 ASTPrinter::EmitTypeInitializer(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 core::type::Array*) {
if (!EmitType(out, type)) {
return false;
}
out << "{";
terminator = "}";
return true;
},
[&](const core::type::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<core::type::Struct>()) {
// Emit field designators for structures to account for padding members.
auto name = struct_ty->Members()[i]->Name().Name();
out << "." << name << "=";
}
if (!EmitExpression(out, arg->Declaration())) {
return false;
}
i++;
}
return true;
}
bool ASTPrinter::EmitAtomicCall(StringStream& out,
const ast::CallExpression* expr,
const sem::BuiltinFn* 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->Fn()) {
case wgsl::BuiltinFn::kAtomicLoad:
return call("atomic_load_explicit", true);
case wgsl::BuiltinFn::kAtomicStore:
return call("atomic_store_explicit", true);
case wgsl::BuiltinFn::kAtomicAdd:
return call("atomic_fetch_add_explicit", true);
case wgsl::BuiltinFn::kAtomicSub:
return call("atomic_fetch_sub_explicit", true);
case wgsl::BuiltinFn::kAtomicMax:
return call("atomic_fetch_max_explicit", true);
case wgsl::BuiltinFn::kAtomicMin:
return call("atomic_fetch_min_explicit", true);
case wgsl::BuiltinFn::kAtomicAnd:
return call("atomic_fetch_and_explicit", true);
case wgsl::BuiltinFn::kAtomicOr:
return call("atomic_fetch_or_explicit", true);
case wgsl::BuiltinFn::kAtomicXor:
return call("atomic_fetch_xor_explicit", true);
case wgsl::BuiltinFn::kAtomicExchange:
return call("atomic_exchange_explicit", true);
case wgsl::BuiltinFn::kAtomicCompareExchangeWeak: {
auto* ptr_ty = TypeOf(expr->args[0])->UnwrapRef()->As<core::type::Pointer>();
auto sc = ptr_ty->AddressSpace();
auto* str = builtin->ReturnType()->As<core::type::Struct>();
auto func = tint::GetOrCreate(
atomicCompareExchangeWeak_, ACEWKeyType{{sc, str}}, [&]() -> std::string {
if (!EmitStructType(&helpers_,
builtin->ReturnType()->As<core::type::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<core::type::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() << "unsupported atomic builtin: " << builtin->Fn();
return false;
}
bool ASTPrinter::EmitTextureCall(StringStream& out,
const sem::Call* call,
const sem::BuiltinFn* builtin) {
using Usage = core::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() << "missing texture arg";
return false;
}
auto* texture_type = TypeOf(texture)->UnwrapRef()->As<core::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() == core::type::TextureDimension::k1d;
switch (builtin->Fn()) {
case wgsl::BuiltinFn::kTextureDimensions: {
std::vector<const char*> dims;
switch (texture_type->dim()) {
case core::type::TextureDimension::kNone:
diagnostics_.add_error(diag::System::Writer, "texture dimension is kNone");
return false;
case core::type::TextureDimension::k1d:
dims = {"width"};
break;
case core::type::TextureDimension::k2d:
case core::type::TextureDimension::k2dArray:
case core::type::TextureDimension::kCube:
case core::type::TextureDimension::kCubeArray:
dims = {"width", "height"};
break;
case core::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 wgsl::BuiltinFn::kTextureNumLayers: {
if (!texture_expr()) {
return false;
}
out << ".get_array_size()";
return true;
}
case wgsl::BuiltinFn::kTextureNumLevels: {
if (!texture_expr()) {
return false;
}
out << ".get_num_mip_levels()";
return true;
}
case wgsl::BuiltinFn::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->Fn()) {
case wgsl::BuiltinFn::kTextureSample:
case wgsl::BuiltinFn::kTextureSampleBias:
case wgsl::BuiltinFn::kTextureSampleLevel:
case wgsl::BuiltinFn::kTextureSampleGrad:
out << ".sample(";
break;
case wgsl::BuiltinFn::kTextureSampleCompare:
case wgsl::BuiltinFn::kTextureSampleCompareLevel:
out << ".sample_compare(";
break;
case wgsl::BuiltinFn::kTextureGather:
out << ".gather(";
break;
case wgsl::BuiltinFn::kTextureGatherCompare:
out << ".gather_compare(";
break;
case wgsl::BuiltinFn::kTextureLoad:
out << ".read(";
lod_param_is_named = false;
break;
case wgsl::BuiltinFn::kTextureStore:
out << ".write(";
break;
default:
TINT_UNREACHABLE() << "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 core::type::TextureDimension::k1d:
out << "uint(";
break;
case core::type::TextureDimension::k2d:
case core::type::TextureDimension::k2dArray:
out << "uint2(";
break;
case core::type::TextureDimension::k3d:
out << "uint3(";
break;
default:
TINT_ICE() << "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->Fn() == wgsl::BuiltinFn::kTextureSampleCompareLevel) {
maybe_write_comma();
out << "level(0)";
}
if (auto* ddx = arg(Usage::kDdx)) {
auto dim = texture_type->dim();
switch (dim) {
case core::type::TextureDimension::k2d:
case core::type::TextureDimension::k2dArray:
maybe_write_comma();
out << "gradient2d(";
break;
case core::type::TextureDimension::k3d:
maybe_write_comma();
out << "gradient3d(";
break;
case core::type::TextureDimension::kCube:
case core::type::TextureDimension::kCubeArray:
maybe_write_comma();
out << "gradientcube(";
break;
default: {
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 core::type::TextureDimension::k2d:
case core::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() << "invalid textureGather component: " << c;
break;
}
}
out << ")";
// If this is a `textureStore()` for a read-write texture, add a fence to ensure that the
// written values are visible to subsequent reads from the same thread.
if (auto* storage = texture_type->As<core::type::StorageTexture>();
builtin->Fn() == wgsl::BuiltinFn::kTextureStore &&
storage->access() == core::Access::kReadWrite) {
out << "; ";
texture_expr();
out << ".fence()";
}
return true;
}
bool ASTPrinter::EmitDotCall(StringStream& out,
const ast::CallExpression* expr,
const sem::BuiltinFn* builtin) {
auto* vec_ty = builtin->Parameters()[0]->Type()->As<core::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 = tint::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 ASTPrinter::EmitDot4I8PackedCall(StringStream& out,
const ast::CallExpression* expr,
const sem::BuiltinFn* builtin) {
return CallBuiltinHelper(
out, expr, builtin, [&](TextBuffer* b, const std::vector<std::string>& params) {
Line(b) << "char4 vec1 = as_type<char4>(" << params[0] << ");";
Line(b) << "char4 vec2 = as_type<char4>(" << params[1] << ");";
Line(b) << "return vec1[0] * vec2[0] + vec1[1] * vec2[1] + vec1[2] * vec2[2] + vec1[3] "
"* vec2[3];";
return true;
});
}
bool ASTPrinter::EmitDot4U8PackedCall(StringStream& out,
const ast::CallExpression* expr,
const sem::BuiltinFn* builtin) {
return CallBuiltinHelper(
out, expr, builtin, [&](TextBuffer* b, const std::vector<std::string>& params) {
Line(b) << "uchar4 vec1 = as_type<uchar4>(" << params[0] << ");";
Line(b) << "uchar4 vec2 = as_type<uchar4>(" << params[1] << ");";
Line(b) << "return vec1[0] * vec2[0] + vec1[1] * vec2[1] + vec1[2] * vec2[2] + vec1[3] "
"* vec2[3];";
return true;
});
}
bool ASTPrinter::EmitModfCall(StringStream& out,
const ast::CallExpression* expr,
const sem::BuiltinFn* 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<core::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<core::type::Struct>())) {
return false;
}
Line(b) << StructName(builtin->ReturnType()->As<core::type::Struct>()) << " result;";
Line(b) << "result.fract = modf(" << in << ", result.whole);";
Line(b) << "return result;";
return true;
});
}
bool ASTPrinter::EmitFrexpCall(StringStream& out,
const ast::CallExpression* expr,
const sem::BuiltinFn* 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<core::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<core::type::Struct>())) {
return false;
}
Line(b) << StructName(builtin->ReturnType()->As<core::type::Struct>()) << " result;";
Line(b) << "result.fract = frexp(" << in << ", result.exp);";
Line(b) << "return result;";
return true;
});
}
bool ASTPrinter::EmitDegreesCall(StringStream& out,
const ast::CallExpression* expr,
const sem::BuiltinFn* 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 ASTPrinter::EmitRadiansCall(StringStream& out,
const ast::CallExpression* expr,
const sem::BuiltinFn* 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 ASTPrinter::generate_builtin_name(const sem::BuiltinFn* builtin) {
std::string out = "";
switch (builtin->Fn()) {
case wgsl::BuiltinFn::kAcos:
case wgsl::BuiltinFn::kAcosh:
case wgsl::BuiltinFn::kAll:
case wgsl::BuiltinFn::kAny:
case wgsl::BuiltinFn::kAsin:
case wgsl::BuiltinFn::kAsinh:
case wgsl::BuiltinFn::kAtanh:
case wgsl::BuiltinFn::kAtan:
case wgsl::BuiltinFn::kAtan2:
case wgsl::BuiltinFn::kCeil:
case wgsl::BuiltinFn::kCos:
case wgsl::BuiltinFn::kCosh:
case wgsl::BuiltinFn::kCross:
case wgsl::BuiltinFn::kDeterminant:
case wgsl::BuiltinFn::kDistance:
case wgsl::BuiltinFn::kDot:
case wgsl::BuiltinFn::kExp:
case wgsl::BuiltinFn::kExp2:
case wgsl::BuiltinFn::kFloor:
case wgsl::BuiltinFn::kFma:
case wgsl::BuiltinFn::kFract:
case wgsl::BuiltinFn::kFrexp:
case wgsl::BuiltinFn::kLength:
case wgsl::BuiltinFn::kLdexp:
case wgsl::BuiltinFn::kLog:
case wgsl::BuiltinFn::kLog2:
case wgsl::BuiltinFn::kMix:
case wgsl::BuiltinFn::kModf:
case wgsl::BuiltinFn::kNormalize:
case wgsl::BuiltinFn::kPow:
case wgsl::BuiltinFn::kReflect:
case wgsl::BuiltinFn::kRefract:
case wgsl::BuiltinFn::kSaturate:
case wgsl::BuiltinFn::kSelect:
case wgsl::BuiltinFn::kSin:
case wgsl::BuiltinFn::kSinh:
case wgsl::BuiltinFn::kSqrt:
case wgsl::BuiltinFn::kStep:
case wgsl::BuiltinFn::kTan:
case wgsl::BuiltinFn::kTanh:
case wgsl::BuiltinFn::kTranspose:
case wgsl::BuiltinFn::kTrunc:
case wgsl::BuiltinFn::kSign:
case wgsl::BuiltinFn::kClamp:
out += builtin->str();
break;
case wgsl::BuiltinFn::kAbs:
if (builtin->ReturnType()->is_float_scalar_or_vector()) {
out += "fabs";
} else {
out += "abs";
}
break;
case wgsl::BuiltinFn::kCountLeadingZeros:
out += "clz";
break;
case wgsl::BuiltinFn::kCountOneBits:
out += "popcount";
break;
case wgsl::BuiltinFn::kCountTrailingZeros:
out += "ctz";
break;
case wgsl::BuiltinFn::kDpdx:
case wgsl::BuiltinFn::kDpdxCoarse:
case wgsl::BuiltinFn::kDpdxFine:
out += "dfdx";
break;
case wgsl::BuiltinFn::kDpdy:
case wgsl::BuiltinFn::kDpdyCoarse:
case wgsl::BuiltinFn::kDpdyFine:
out += "dfdy";
break;
case wgsl::BuiltinFn::kExtractBits:
out += "extract_bits";
break;
case wgsl::BuiltinFn::kInsertBits:
out += "insert_bits";
break;
case wgsl::BuiltinFn::kFwidth:
case wgsl::BuiltinFn::kFwidthCoarse:
case wgsl::BuiltinFn::kFwidthFine:
out += "fwidth";
break;
case wgsl::BuiltinFn::kMax:
if (builtin->ReturnType()->is_float_scalar_or_vector()) {
out += "fmax";
} else {
out += "max";
}
break;
case wgsl::BuiltinFn::kMin:
if (builtin->ReturnType()->is_float_scalar_or_vector()) {
out += "fmin";
} else {
out += "min";
}
break;
case wgsl::BuiltinFn::kFaceForward:
out += "faceforward";
break;
case wgsl::BuiltinFn::kPack4X8Snorm:
out += "pack_float_to_snorm4x8";
break;
case wgsl::BuiltinFn::kPack4X8Unorm:
out += "pack_float_to_unorm4x8";
break;
case wgsl::BuiltinFn::kPack2X16Snorm:
out += "pack_float_to_snorm2x16";
break;
case wgsl::BuiltinFn::kPack2X16Unorm:
out += "pack_float_to_unorm2x16";
break;
case wgsl::BuiltinFn::kReverseBits:
out += "reverse_bits";
break;
case wgsl::BuiltinFn::kRound:
out += "rint";
break;
case wgsl::BuiltinFn::kSmoothstep:
out += "smoothstep";
break;
case wgsl::BuiltinFn::kInverseSqrt:
out += "rsqrt";
break;
case wgsl::BuiltinFn::kUnpack4X8Snorm:
out += "unpack_snorm4x8_to_float";
break;
case wgsl::BuiltinFn::kUnpack4X8Unorm:
out += "unpack_unorm4x8_to_float";
break;
case wgsl::BuiltinFn::kUnpack2X16Snorm:
out += "unpack_snorm2x16_to_float";
break;
case wgsl::BuiltinFn::kUnpack2X16Unorm:
out += "unpack_unorm2x16_to_float";
break;
case wgsl::BuiltinFn::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 ASTPrinter::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 ASTPrinter::EmitContinue(const ast::ContinueStatement*) {
if (!emit_continuing_ || !emit_continuing_()) {
return false;
}
Line() << "continue;";
return true;
}
bool ASTPrinter::EmitZeroValue(StringStream& out, const core::type::Type* type) {
return Switch(
type,
[&](const core::type::Bool*) {
out << "false";
return true;
},
[&](const core::type::F16*) {
out << "0.0h";
return true;
},
[&](const core::type::F32*) {
out << "0.0f";
return true;
},
[&](const core::type::I32*) {
out << "0";
return true;
},
[&](const core::type::U32*) {
out << "0u";
return true;
},
[&](const core::type::Vector* vec) { //
return EmitZeroValue(out, vec->type());
},
[&](const core::type::Matrix* mat) {
if (!EmitType(out, mat)) {
return false;
}
ScopedParen sp(out);
return EmitZeroValue(out, mat->type());
},
[&](const core::type::Array*) {
out << "{}";
return true;
},
[&](const core::type::Struct*) {
out << "{}";
return true;
}, //
TINT_ICE_ON_NO_MATCH);
}
bool ASTPrinter::EmitConstant(StringStream& out, const core::constant::Value* constant) {
return Switch(
constant->Type(), //
[&](const core::type::Bool*) {
out << (constant->ValueAs<AInt>() ? "true" : "false");
return true;
},
[&](const core::type::F32*) {
PrintF32(out, constant->ValueAs<f32>());
return true;
},
[&](const core::type::F16*) {
PrintF16(out, constant->ValueAs<f16>());
return true;
},
[&](const core::type::I32*) {
PrintI32(out, constant->ValueAs<i32>());
return true;
},
[&](const core::type::U32*) {
out << constant->ValueAs<AInt>() << "u";
return true;
},
[&](const core::type::Vector* v) {
if (!EmitType(out, v)) {
return false;
}
ScopedParen sp(out);
if (auto* splat = constant->As<core::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 core::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 core::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,
core::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 core::type::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 << "." << members[i]->Name().Name() << "=";
if (!EmitConstant(out, constant->Index(i))) {
return false;
}
}
return true;
}, //
TINT_ICE_ON_NO_MATCH);
}
bool ASTPrinter::EmitLiteral(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;
}, //
TINT_ICE_ON_NO_MATCH);
}
bool ASTPrinter::EmitExpression(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); }, //
TINT_ICE_ON_NO_MATCH);
}
void ASTPrinter::EmitStage(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 ASTPrinter::EmitFunction(const ast::Function* func) {
if (func->body == nullptr) {
// An internal function. Do not emit.
return true;
}
auto* func_sem = builder_.Sem().Get(func);
{
auto out = Line();
if (!EmitType(out, func_sem->ReturnType())) {
return false;
}
out << " " << func->name->symbol.Name() << "(";
bool first = true;
for (auto* v : func->params) {
if (!first) {
out << ", ";
}
first = false;
auto* type = builder_.Sem().Get(v)->Type();
if (!EmitType(out, type)) {
return false;
}
if (type->Is<core::type::Pointer>()) {
out << " const";
}
out << " " << v->name->symbol.Name();
}
out << ") {";
}
if (!EmitStatementsWithIndent(func->body->statements)) {
return false;
}
Line() << "}";
return true;
}
bool ASTPrinter::EmitEntryPointFunction(const ast::Function* func) {
auto* func_sem = builder_.Sem().Get(func);
auto func_name = func->name->symbol.Name();
workgroup_allocations_.insert({func_name, {}});
// 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() << "missing binding attributes for entry point parameter";
return kInvalidBindingIndex;
}
auto* param_sem = builder_.Sem().Get(param);
auto bp = param_sem->Attributes().binding_point;
if (TINT_UNLIKELY(bp->group != 0)) {
TINT_ICE() << "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 = builder_.Sem().Get(param)->Type()->UnwrapRef();
if (!EmitType(out, type)) {
return false;
}
out << " " << param->name->symbol.Name();
bool ok = Switch(
type, //
[&](const core::type::Struct*) {
out << " [[stage_in]]";
return true;
},
[&](const core::type::Texture*) {
uint32_t binding = get_binding_index(param);
if (binding == kInvalidBindingIndex) {
return false;
}
out << " [[texture(" << binding << ")]]";
return true;
},
[&](const core::type::Sampler*) {
uint32_t binding = get_binding_index(param);
if (binding == kInvalidBindingIndex) {
return false;
}
out << " [[sampler(" << binding << ")]]";
return true;
},
[&](const core::type::Pointer* ptr) {
switch (ptr->AddressSpace()) {
case core::AddressSpace::kWorkgroup: {
auto& allocations = workgroup_allocations_[func_name];
out << " [[threadgroup(" << allocations.size() << ")]]";
allocations.push_back(ptr->StoreType()->Size());
return true;
}
case core::AddressSpace::kStorage:
case core::AddressSpace::kUniform: {
uint32_t binding = get_binding_index(param);
if (binding == kInvalidBindingIndex) {
return false;
}
out << " [[buffer(" << binding << ")]]";
return true;
}
default:
break;
}
TINT_ICE() << "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 = builder_.Sem().Get(builtin_attr)->Value();
builtin_found = true;
auto name = BuiltinToAttribute(builtin);
if (name.empty()) {
diagnostics_.add_error(diag::System::Writer, "unknown builtin");
return false;
}
out << " [[" << name << "]]";
}
if (TINT_UNLIKELY(!builtin_found)) {
TINT_ICE() << "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(GenerationID{}, ast::NodeID{}, Source{});
if (!EmitStatement(&ret)) {
return false;
}
}
}
Line() << "}";
return true;
}
bool ASTPrinter::EmitIdentifier(StringStream& out, const ast::IdentifierExpression* expr) {
out << expr->identifier->symbol.Name();
return true;
}
bool ASTPrinter::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) {";
EmitLoopPreserver();
{
ScopedIndent si(this);
if (!EmitStatements(stmt->body->statements)) {
return false;
}
if (!emit_continuing_()) {
return false;
}
}
Line() << "}";
return true;
}
bool ASTPrinter::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;
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() << "{";
IncrementIndent();
current_buffer_->Append(init_buf);
init_buf.lines.clear(); // Don't emit the initializer again in the 'for'
}
TINT_DEFER({
if (nest_in_block) {
DecrementIndent();
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) {";
EmitLoopPreserver();
IncrementIndent();
TINT_DEFER({
DecrementIndent();
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 << tint::TrimSuffix(cont_buf.lines[0].content, ";");
}
}
out << " {";
}
EmitLoopPreserver();
{
auto emit_continuing = [] { return true; };
TINT_SCOPED_ASSIGNMENT(emit_continuing_, emit_continuing);
if (!EmitStatementsWithIndent(stmt->body->statements)) {
return false;
}
}
Line() << "}";
}
return true;
}
bool ASTPrinter::EmitWhile(const ast::WhileStatement* stmt) {
TextBuffer cond_pre;
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) {";
EmitLoopPreserver();
IncrementIndent();
TINT_DEFER({
DecrementIndent();
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 << " {";
}
EmitLoopPreserver();
if (!EmitStatementsWithIndent(stmt->body->statements)) {
return false;
}
Line() << "}";
}
return true;
}
bool ASTPrinter::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 ASTPrinter::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(Vector{stmt->else_statement})) {
return false;
}
}
}
Line() << "}";
return true;
}
bool ASTPrinter::EmitMemberAccessor(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 << "." << expr->member->symbol.Name();
}
return true;
},
[&](const sem::StructMemberAccess* member_access) {
if (!write_lhs()) {
return false;
}
out << "." << member_access->Member()->Name().Name();
return true;
}, //
TINT_ICE_ON_NO_MATCH);
}
bool ASTPrinter::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 ASTPrinter::EmitBlock(const ast::BlockStatement* stmt) {
Line() << "{";
if (!EmitStatementsWithIndent(stmt->statements)) {
return false;
}
Line() << "}";
return true;
}
bool ASTPrinter::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
}, //
TINT_ICE_ON_NO_MATCH);
},
[&](const ast::ConstAssert*) {
return true; // Not emitted
}, //
TINT_ICE_ON_NO_MATCH);
}
bool ASTPrinter::EmitStatements(VectorRef<const ast::Statement*> stmts) {
for (auto* s : stmts) {
if (!EmitStatement(s)) {
return false;
}
}
return true;
}
bool ASTPrinter::EmitStatementsWithIndent(VectorRef<const ast::Statement*> stmts) {
ScopedIndent si(this);
return EmitStatements(stmts);
}
bool ASTPrinter::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 ASTPrinter::EmitType(StringStream& out, const core::type::Type* type) {
return Switch(
type,
[&](const core::type::Atomic* atomic) {
if (atomic->Type()->Is<core::type::I32>()) {
out << "atomic_int";
return true;
}
if (TINT_LIKELY(atomic->Type()->Is<core::type::U32>())) {
out << "atomic_uint";
return true;
}
TINT_ICE() << "unhandled atomic type " << atomic->Type()->FriendlyName();
return false;
},
[&](const core::type::Array* arr) {
out << ArrayType() << "<";
if (!EmitType(out, arr->ElemType())) {
return false;
}
out << ", ";
if (arr->Count()->Is<core::type::RuntimeArrayCount>()) {
out << "1";
} else {
auto count = arr->ConstantCount();
if (!count) {
diagnostics_.add_error(diag::System::Writer,
core::type::Array::kErrExpectedConstantCount);
return false;
}
out << count.value();
}
out << ">";
return true;
},
[&](const core::type::Bool*) {
out << "bool";
return true;
},
[&](const core::type::F16*) {
out << "half";
return true;
},
[&](const core::type::F32*) {
out << "float";
return true;
},
[&](const core::type::I32*) {
out << "int";
return true;
},
[&](const core::type::Matrix* mat) {
if (!EmitType(out, mat->type())) {
return false;
}
out << mat->columns() << "x" << mat->rows();
return true;
},
[&](const core::type::Pointer* ptr) {
if (ptr->Access() == core::Access::kRead) {
out << "const ";
}
if (!EmitAddressSpace(out, ptr->AddressSpace())) {
return false;
}
out << " ";
if (!EmitType(out, ptr->StoreType())) {
return false;
}
out << "*";
return true;
},
[&](const core::type::Sampler*) {
out << "sampler";
return true;
},
[&](const core::type::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 core::type::Texture* tex) {
if (TINT_UNLIKELY(tex->Is<core::type::ExternalTexture>())) {
TINT_ICE() << "Multiplanar external texture transform was not run.";
return false;
}
if (tex->IsAnyOf<core::type::DepthTexture, core::type::DepthMultisampledTexture>()) {
out << "depth";
} else {
out << "texture";
}
switch (tex->dim()) {
case core::type::TextureDimension::k1d:
out << "1d";
break;
case core::type::TextureDimension::k2d:
out << "2d";
break;
case core::type::TextureDimension::k2dArray:
out << "2d_array";
break;
case core::type::TextureDimension::k3d:
out << "3d";
break;
case core::type::TextureDimension::kCube:
out << "cube";
break;
case core::type::TextureDimension::kCubeArray:
out << "cube_array";
break;
default:
diagnostics_.add_error(diag::System::Writer, "Invalid texture dimensions");
return false;
}
if (tex->IsAnyOf<core::type::MultisampledTexture,
core::type::DepthMultisampledTexture>()) {
out << "_ms";
}
out << "<";
TINT_DEFER(out << ">");
return Switch(
tex,
[&](const core::type::DepthTexture*) {
out << "float, access::sample";
return true;
},
[&](const core::type::DepthMultisampledTexture*) {
out << "float, access::read";
return true;
},
[&](const core::type::StorageTexture* storage) {
if (!EmitType(out, storage->type())) {
return false;
}
std::string access_str;
if (storage->access() == core::Access::kRead) {
out << ", access::read";
} else if (storage->access() == core::Access::kReadWrite) {
out << ", access::read_write";
} else if (storage->access() == core::Access::kWrite) {
out << ", access::write";
} else {
diagnostics_.add_error(diag::System::Writer,
"Invalid access control for storage texture");
return false;
}
return true;
},
[&](const core::type::MultisampledTexture* ms) {
if (!EmitType(out, ms->type())) {
return false;
}
out << ", access::read";
return true;
},
[&](const core::type::SampledTexture* sampled) {
if (!EmitType(out, sampled->type())) {
return false;
}
out << ", access::sample";
return true;
}, //
TINT_ICE_ON_NO_MATCH);
},
[&](const core::type::U32*) {
out << "uint";
return true;
},
[&](const core::type::Vector* vec) {
if (vec->Packed()) {
out << "packed_";
}
if (!EmitType(out, vec->type())) {
return false;
}
out << vec->Width();
return true;
},
[&](const core::type::Void*) {
out << "void";
return true;
}, //
TINT_ICE_ON_NO_MATCH);
}
bool ASTPrinter::EmitTypeAndName(StringStream& out,
const core::type::Type* type,
const std::string& name) {
if (!EmitType(out, type)) {
return false;
}
out << " " << name;
return true;
}
bool ASTPrinter::EmitAddressSpace(StringStream& out, core::AddressSpace sc) {
switch (sc) {
case core::AddressSpace::kFunction:
case core::AddressSpace::kPrivate:
case core::AddressSpace::kHandle:
out << "thread";
return true;
case core::AddressSpace::kWorkgroup:
out << "threadgroup";
return true;
case core::AddressSpace::kStorage:
out << "device";
return true;
case core::AddressSpace::kUniform:
out << "constant";
return true;
default:
break;
}
TINT_ICE() << "unhandled address space: " << sc;
return false;
}
bool ASTPrinter::EmitStructType(TextBuffer* b, const core::type::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 = [&](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(builder_.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 = mem->Name().Name();
auto wgsl_offset = mem->Offset();
if (is_host_shareable) {
if (TINT_UNLIKELY(wgsl_offset < msl_offset)) {
// Unimplementable layout
TINT_ICE() << "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())) {
return false;
}
auto* ty = mem->Type();
out << " " << mem_name;
// Emit attributes
auto& attributes = mem->Attributes();
if (auto builtin = attributes.builtin) {
auto name = BuiltinToAttribute(builtin.value());
if (name.empty()) {
diagnostics_.add_error(diag::System::Writer, "unknown builtin");
return false;
}
out << " [[" << name << "]]";
}
if (auto location = attributes.location) {
auto& pipeline_stage_uses = str->PipelineStageUses();
if (TINT_UNLIKELY(pipeline_stage_uses.size() != 1)) {
TINT_ICE() << "invalid entry point IO struct uses for " << str->Name().NameView();
return false;
}
if (pipeline_stage_uses.count(core::type::PipelineStageUsage::kVertexInput)) {
out << " [[attribute(" + std::to_string(location.value()) + ")]]";
} else if (pipeline_stage_uses.count(core::type::PipelineStageUsage::kVertexOutput)) {
out << " [[user(locn" + std::to_string(location.value()) + ")]]";
} else if (pipeline_stage_uses.count(core::type::PipelineStageUsage::kFragmentInput)) {
out << " [[user(locn" + std::to_string(location.value()) + ")]]";
} else if (TINT_LIKELY(pipeline_stage_uses.count(
core::type::PipelineStageUsage::kFragmentOutput))) {
if (auto index = attributes.index) {
out << " [[color(" + std::to_string(location.value()) + ") index(" +
std::to_string(index.value()) + ")]]";
} else {
out << " [[color(" + std::to_string(location.value()) + ")]]";
}
} else {
TINT_ICE() << "invalid use of location decoration";
return false;
}
}
if (auto color = attributes.color) {
out << " [[color(" + std::to_string(color.value()) + ")]]";
}
if (auto interpolation = attributes.interpolation) {
auto name = InterpolationToAttribute(interpolation->type, interpolation->sampling);
if (name.empty()) {
diagnostics_.add_error(diag::System::Writer, "unknown interpolation attribute");
return false;
}
out << " [[" << name << "]]";
}
if (attributes.invariant) {
invariant_define_name_ = UniqueIdentifier("TINT_INVARIANT");
out << " " << invariant_define_name_;
}
out << ";";
if (is_host_shareable) {
// Calculate new MSL offset
auto size_align = MslPackedTypeSizeAndAlign(ty);
if (TINT_UNLIKELY(msl_offset % size_align.align)) {
TINT_ICE() << "Misaligned MSL structure member " << ty->FriendlyName() << " "
<< 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 ASTPrinter::EmitUnaryOp(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 == core::UnaryOp::kNegation && expr_type->is_signed_integer_scalar_or_vector()) {
auto fn = tint::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 core::UnaryOp::kAddressOf:
out << "&";
break;
case core::UnaryOp::kComplement:
out << "~";
break;
case core::UnaryOp::kIndirection:
out << "*";
break;
case core::UnaryOp::kNot:
out << "!";
break;
case core::UnaryOp::kNegation:
out << "-";
break;
}
out << "(";
if (!EmitExpression(out, expr->expr)) {
return false;
}
out << ")";
return true;
}
bool ASTPrinter::EmitVar(const ast::Var* var) {
auto* sem = builder_.Sem().Get(var);
auto* type = sem->Type()->UnwrapRef();
auto out = Line();
switch (sem->AddressSpace()) {
case core::AddressSpace::kFunction:
case core::AddressSpace::kHandle:
break;
case core::AddressSpace::kPrivate:
out << "thread ";
break;
case core::AddressSpace::kWorkgroup:
out << "threadgroup ";
break;
default:
TINT_ICE() << "unhandled variable address space";
return false;
}
if (!EmitType(out, type)) {
return false;
}
out << " " << var->name->symbol.Name();
if (var->initializer != nullptr) {
out << " = ";
if (!EmitExpression(out, var->initializer)) {
return false;
}
} else if (sem->AddressSpace() == core::AddressSpace::kPrivate ||
sem->AddressSpace() == core::AddressSpace::kFunction ||
sem->AddressSpace() == core::AddressSpace::kUndefined) {
out << " = ";
if (!EmitZeroValue(out, type)) {
return false;
}
}
out << ";";
return true;
}
bool ASTPrinter::EmitLet(const ast::Let* let) {
auto* sem = builder_.Sem().Get(let);
auto* type = sem->Type();
auto out = Line();
switch (sem->AddressSpace()) {
case core::AddressSpace::kFunction:
case core::AddressSpace::kHandle:
case core::AddressSpace::kUndefined:
break;
case core::AddressSpace::kPrivate:
out << "thread ";
break;
case core::AddressSpace::kWorkgroup:
out << "threadgroup ";
break;
default:
TINT_ICE() << "unhandled variable address space";
return false;
}
if (!EmitType(out, type)) {
return false;
}
out << " const " << let->name->symbol.Name();
out << " = ";
if (!EmitExpression(out, let->initializer)) {
return false;
}
out << ";";
return true;
}
void ASTPrinter::EmitLoopPreserver() {
IncrementIndent();
// This statement prevents the MSL compiler from erasing a loop during
// optimizations. In the AIR dialiect of LLVM IR, WGSL loops should compile
// to a loop that contains an 'asm' call with a 'sideeffect' annotation.
//
// For example, compile a WGSL file with a trivial while(1) loop to 'a.metal',
// then compile that to AIR (LLVM IR dialect):
//
// xcrun metal a.metal -S -o -
//
// The loop in the AIR should look something like this:
//
// 1: ...
// br label %2
//
// 2: ; preds = %1, %2
// tail call void asm sideeffect "", ""() #1, !srcloc !27
// br label %2, !llvm.loop !28
//
// It is important that the 'sideeffect' annotation exist. That tells the
// optimizer that the instruction has side effects invisible to the
// optimizer, and therefore the loop should not be eliminated.
Line() << R"(__asm__("");)";
DecrementIndent();
}
template <typename F>
bool ASTPrinter::CallBuiltinHelper(StringStream& out,
const ast::CallExpression* call,
const sem::BuiltinFn* builtin,
F&& build) {
// Generate the helper function if it hasn't been created already
auto fn = tint::GetOrCreate(builtins_, builtin, [&]() -> std::string {
TextBuffer b;
TINT_DEFER(helpers_.Append(b));
auto fn_name = UniqueIdentifier(std::string("tint_") + wgsl::str(builtin->Fn()));
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& ASTPrinter::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_;
}
std::string ASTPrinter::StructName(const core::type::Struct* s) {
auto name = s->Name().Name();
if (HasPrefix(name, "__")) {
name = tint::GetOrCreate(builtin_struct_names_, s,
[&] { return UniqueIdentifier(name.substr(2)); });
}
return name;
}
std::string ASTPrinter::UniqueIdentifier(const std::string& prefix /* = "" */) {
return builder_.Symbols().New(prefix).Name();
}
} // namespace tint::msl::writer