[hlsl-writer] Emit specialization variables
This CL adds specialization to the HLSL backend. The specialization is
emulated using defined preprocessor macros.
Bug: tint:154
Change-Id: I73ab42360558967eee9a0da6bbe74d513fe4cc57
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/29720
Commit-Queue: David Neto <dneto@google.com>
Reviewed-by: David Neto <dneto@google.com>
diff --git a/src/writer/hlsl/generator_impl.cc b/src/writer/hlsl/generator_impl.cc
index 86eef79..1ed6c02 100644
--- a/src/writer/hlsl/generator_impl.cc
+++ b/src/writer/hlsl/generator_impl.cc
@@ -2053,7 +2053,7 @@
const ast::Variable* var) {
make_indent(out);
- if (var->IsDecorated()) {
+ if (var->IsDecorated() && !var->AsDecorated()->HasConstantIdDecoration()) {
error_ = "Decorated const values not valid";
return false;
}
@@ -2064,8 +2064,6 @@
std::ostringstream constructor_out;
if (var->constructor() != nullptr) {
- constructor_out << " = ";
-
std::ostringstream pre;
if (!EmitExpression(pre, constructor_out, var->constructor())) {
return false;
@@ -2073,14 +2071,40 @@
out << pre.str();
}
- out << "static const ";
- if (!EmitType(out, var->type(), var->name())) {
- return false;
+ if (var->IsDecorated() && var->AsDecorated()->HasConstantIdDecoration()) {
+ auto const_id = var->AsDecorated()->constant_id();
+
+ out << "#ifndef WGSL_SPEC_CONSTANT_" << const_id << std::endl;
+
+ if (var->constructor() != nullptr) {
+ out << "#define WGSL_SPEC_CONSTANT_" << const_id << " "
+ << constructor_out.str() << std::endl;
+ } else {
+ out << "#error spec constant required for constant id " << const_id
+ << std::endl;
+ }
+ out << "#endif" << std::endl;
+ out << "static const ";
+ if (!EmitType(out, var->type(), var->name())) {
+ return false;
+ }
+ out << " " << var->name() << " = WGSL_SPEC_CONSTANT_" << const_id << ";"
+ << std::endl;
+ out << "#undef WGSL_SPEC_CONSTANT_" << const_id << std::endl;
+ } else {
+ out << "static const ";
+ if (!EmitType(out, var->type(), var->name())) {
+ return false;
+ }
+ if (!var->type()->IsArray()) {
+ out << " " << var->name();
+ }
+
+ if (var->constructor() != nullptr) {
+ out << " = " << constructor_out.str();
+ }
+ out << ";" << std::endl;
}
- if (!var->type()->IsArray()) {
- out << " " << var->name();
- }
- out << constructor_out.str() << ";" << std::endl;
return true;
}
diff --git a/src/writer/hlsl/generator_impl_module_constant_test.cc b/src/writer/hlsl/generator_impl_module_constant_test.cc
index abad8ea..94ffb8e 100644
--- a/src/writer/hlsl/generator_impl_module_constant_test.cc
+++ b/src/writer/hlsl/generator_impl_module_constant_test.cc
@@ -15,6 +15,8 @@
#include <memory>
#include <vector>
+#include "src/ast/constant_id_decoration.h"
+#include "src/ast/decorated_variable.h"
#include "src/ast/float_literal.h"
#include "src/ast/module.h"
#include "src/ast/scalar_constructor_expression.h"
@@ -56,6 +58,50 @@
"static const float pos[3] = {1.00000000f, 2.00000000f, 3.00000000f};\n");
}
+TEST_F(HlslGeneratorImplTest_ModuleConstant, Emit_SpecConstant) {
+ ast::type::F32Type f32;
+
+ ast::VariableDecorationList decos;
+ decos.push_back(std::make_unique<ast::ConstantIdDecoration>(23));
+
+ auto var = std::make_unique<ast::DecoratedVariable>(
+ std::make_unique<ast::Variable>("pos", ast::StorageClass::kNone, &f32));
+ var->set_decorations(std::move(decos));
+ var->set_is_const(true);
+ var->set_constructor(std::make_unique<ast::ScalarConstructorExpression>(
+ std::make_unique<ast::FloatLiteral>(&f32, 3.0f)));
+
+ ASSERT_TRUE(gen().EmitProgramConstVariable(out(), var.get()))
+ << gen().error();
+ EXPECT_EQ(result(), R"(#ifndef WGSL_SPEC_CONSTANT_23
+#define WGSL_SPEC_CONSTANT_23 3.00000000f
+#endif
+static const float pos = WGSL_SPEC_CONSTANT_23;
+#undef WGSL_SPEC_CONSTANT_23
+)");
+}
+
+TEST_F(HlslGeneratorImplTest_ModuleConstant, Emit_SpecConstant_NoConstructor) {
+ ast::type::F32Type f32;
+
+ ast::VariableDecorationList decos;
+ decos.push_back(std::make_unique<ast::ConstantIdDecoration>(23));
+
+ auto var = std::make_unique<ast::DecoratedVariable>(
+ std::make_unique<ast::Variable>("pos", ast::StorageClass::kNone, &f32));
+ var->set_decorations(std::move(decos));
+ var->set_is_const(true);
+
+ ASSERT_TRUE(gen().EmitProgramConstVariable(out(), var.get()))
+ << gen().error();
+ EXPECT_EQ(result(), R"(#ifndef WGSL_SPEC_CONSTANT_23
+#error spec constant required for constant id 23
+#endif
+static const float pos = WGSL_SPEC_CONSTANT_23;
+#undef WGSL_SPEC_CONSTANT_23
+)");
+}
+
} // namespace
} // namespace hlsl
} // namespace writer
