[msl-writer] Emit storage buffers.

This Cl adds the emission of storage buffers to the MSL backend.

Bug: tint:8
Change-Id: I6923926b36e73f2e351443cf1d2bf6d70873bc9a
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/25264
Reviewed-by: David Neto <dneto@google.com>

src/ast/function.cc

@@ -99,6 +99,34 @@ Function::referenced_uniform_variables() const {
   return ret;
 }
 
+const std::vector<std::pair<Variable*, Function::BindingInfo>>
+Function::referenced_storagebuffer_variables() const {
+  std::vector<std::pair<Variable*, Function::BindingInfo>> ret;
+
+  for (auto* var : referenced_module_variables()) {
+    if (!var->IsDecorated() ||
+        var->storage_class() != ast::StorageClass::kStorageBuffer) {
+      continue;
+    }
+
+    BindingDecoration* binding = nullptr;
+    SetDecoration* set = nullptr;
+    for (const auto& deco : var->AsDecorated()->decorations()) {
+      if (deco->IsBinding()) {
+        binding = deco->AsBinding();
+      } else if (deco->IsSet()) {
+        set = deco->AsSet();
+      }
+    }
+    if (binding == nullptr || set == nullptr) {
+      continue;
+    }
+
+    ret.push_back({var, BindingInfo{binding, set}});
+  }
+  return ret;
+}
+
 const std::vector<std::pair<Variable*, BuiltinDecoration*>>
 Function::referenced_builtin_variables() const {
   std::vector<std::pair<Variable*, BuiltinDecoration*>> ret;

src/ast/function.h

@@ -101,6 +101,11 @@ class Function : public Node {
   /// @returns the referenced uniforms
   const std::vector<std::pair<Variable*, Function::BindingInfo>>
   referenced_uniform_variables() const;
+  /// Retrieves any referenced storagebuffer variables. Note, the storagebuffer
+  /// must be decorated with both binding and set decorations.
+  /// @returns the referenced storagebuffers
+  const std::vector<std::pair<Variable*, Function::BindingInfo>>
+  referenced_storagebuffer_variables() const;
 
   /// Adds an ancestor entry point
   /// @param ep the entry point ancestor

src/writer/msl/generator_impl.cc

@@ -464,6 +464,15 @@ bool GeneratorImpl::EmitCall(ast::CallExpression* expr) {
       out_ << var->name();
     }
 
+    for (const auto& data : func->referenced_storagebuffer_variables()) {
+      auto* var = data.first;
+      if (!first) {
+        out_ << ", ";
+      }
+      first = false;
+      out_ << var->name();
+    }
+
     const auto& params = expr->params();
     for (const auto& param : params) {
       if (!first) {
@@ -1061,7 +1070,20 @@ bool GeneratorImpl::EmitFunctionInternal(ast::Function* func,
     out_ << "& " << var->name();
   }
 
-  // TODO(dsinclair): Binding/Set inputs
+  for (const auto& data : func->referenced_storagebuffer_variables()) {
+    auto* var = data.first;
+    if (!first) {
+      out_ << ", ";
+    }
+    first = false;
+
+    out_ << "device ";
+    // TODO(dsinclair): Can arrays be in storage buffers? If so, fix this ...
+    if (!EmitType(var->type(), "")) {
+      return false;
+    }
+    out_ << "& " << var->name();
+  }
 
   for (const auto& v : func->params()) {
     if (!first) {
@@ -1209,7 +1231,27 @@ bool GeneratorImpl::EmitEntryPointFunction(ast::EntryPoint* ep) {
     out_ << "& " << var->name() << " [[buffer(" << binding->value() << ")]]";
   }
 
-  // TODO(dsinclair): Binding/Set inputs
+  for (auto data : func->referenced_storagebuffer_variables()) {
+    if (!first) {
+      out_ << ", ";
+    }
+    first = false;
+
+    auto* var = data.first;
+    // TODO(dsinclair): We're using the binding to make up the buffer number but
+    // we should instead be using a provided mapping that uses both buffer and
+    // set. https://bugs.chromium.org/p/tint/issues/detail?id=104
+    auto* binding = data.second.binding;
+    // auto* set = data.second.set;
+
+    out_ << "device ";
+    // TODO(dsinclair): Can you have a storagebuffer have an array? If so, this
+    // needs to be updated to handle arrays property.
+    if (!EmitType(var->type(), "")) {
+      return false;
+    }
+    out_ << "& " << var->name() << " [[buffer(" << binding->value() << ")]]";
+  }
 
   out_ << ") {" << std::endl;
 

src/writer/msl/generator_impl_function_test.cc

@@ -344,6 +344,62 @@ fragment void frag_main(constant float4& coord [[buffer(0)]]) {
 )");
 }
 
+TEST_F(MslGeneratorImplTest, Emit_Function_EntryPoint_With_StorageBuffer) {
+  ast::type::VoidType void_type;
+  ast::type::F32Type f32;
+  ast::type::VectorType vec4(&f32, 4);
+
+  auto coord_var =
+      std::make_unique<ast::DecoratedVariable>(std::make_unique<ast::Variable>(
+          "coord", ast::StorageClass::kStorageBuffer, &vec4));
+
+  ast::VariableDecorationList decos;
+  decos.push_back(std::make_unique<ast::BindingDecoration>(0));
+  decos.push_back(std::make_unique<ast::SetDecoration>(1));
+  coord_var->set_decorations(std::move(decos));
+
+  Context ctx;
+  ast::Module mod;
+  TypeDeterminer td(&ctx, &mod);
+  td.RegisterVariableForTesting(coord_var.get());
+
+  mod.AddGlobalVariable(std::move(coord_var));
+
+  ast::VariableList params;
+  auto func = std::make_unique<ast::Function>("frag_main", std::move(params),
+                                              &void_type);
+
+  auto var =
+      std::make_unique<ast::Variable>("v", ast::StorageClass::kFunction, &f32);
+  var->set_constructor(std::make_unique<ast::MemberAccessorExpression>(
+      std::make_unique<ast::IdentifierExpression>("coord"),
+      std::make_unique<ast::IdentifierExpression>("x")));
+
+  ast::StatementList body;
+  body.push_back(std::make_unique<ast::VariableDeclStatement>(std::move(var)));
+  body.push_back(std::make_unique<ast::ReturnStatement>());
+  func->set_body(std::move(body));
+
+  mod.AddFunction(std::move(func));
+
+  auto ep = std::make_unique<ast::EntryPoint>(ast::PipelineStage::kFragment, "",
+                                              "frag_main");
+  mod.AddEntryPoint(std::move(ep));
+
+  ASSERT_TRUE(td.Determine()) << td.error();
+
+  GeneratorImpl g(&mod);
+  ASSERT_TRUE(g.Generate()) << g.error();
+  EXPECT_EQ(g.result(), R"(#include <metal_stdlib>
+
+fragment void frag_main(device float4& coord [[buffer(0)]]) {
+  float v = coord.x;
+  return;
+}
+
+)");
+}
+
 TEST_F(MslGeneratorImplTest,
        Emit_Function_Called_By_EntryPoints_WithLocationGlobals_And_Params) {
   ast::type::VoidType void_type;
@@ -616,6 +672,84 @@ fragment void frag_main(constant float4& coord [[buffer(0)]]) {
 )");
 }
 
+TEST_F(MslGeneratorImplTest,
+       Emit_Function_Called_By_EntryPoint_With_StorageBuffer) {
+  ast::type::VoidType void_type;
+  ast::type::F32Type f32;
+  ast::type::VectorType vec4(&f32, 4);
+
+  auto coord_var =
+      std::make_unique<ast::DecoratedVariable>(std::make_unique<ast::Variable>(
+          "coord", ast::StorageClass::kStorageBuffer, &vec4));
+
+  ast::VariableDecorationList decos;
+  decos.push_back(std::make_unique<ast::BindingDecoration>(0));
+  decos.push_back(std::make_unique<ast::SetDecoration>(1));
+  coord_var->set_decorations(std::move(decos));
+
+  Context ctx;
+  ast::Module mod;
+  TypeDeterminer td(&ctx, &mod);
+  td.RegisterVariableForTesting(coord_var.get());
+
+  mod.AddGlobalVariable(std::move(coord_var));
+
+  ast::VariableList params;
+  params.push_back(std::make_unique<ast::Variable>(
+      "param", ast::StorageClass::kFunction, &f32));
+  auto sub_func =
+      std::make_unique<ast::Function>("sub_func", std::move(params), &f32);
+
+  ast::StatementList body;
+  body.push_back(std::make_unique<ast::ReturnStatement>(
+      std::make_unique<ast::MemberAccessorExpression>(
+          std::make_unique<ast::IdentifierExpression>("coord"),
+          std::make_unique<ast::IdentifierExpression>("x"))));
+  sub_func->set_body(std::move(body));
+
+  mod.AddFunction(std::move(sub_func));
+
+  auto func = std::make_unique<ast::Function>("frag_main", std::move(params),
+                                              &void_type);
+
+  ast::ExpressionList expr;
+  expr.push_back(std::make_unique<ast::ScalarConstructorExpression>(
+      std::make_unique<ast::FloatLiteral>(&f32, 1.0f)));
+
+  auto var =
+      std::make_unique<ast::Variable>("v", ast::StorageClass::kFunction, &f32);
+  var->set_constructor(std::make_unique<ast::CallExpression>(
+      std::make_unique<ast::IdentifierExpression>("sub_func"),
+      std::move(expr)));
+
+  body.push_back(std::make_unique<ast::VariableDeclStatement>(std::move(var)));
+  body.push_back(std::make_unique<ast::ReturnStatement>());
+  func->set_body(std::move(body));
+
+  mod.AddFunction(std::move(func));
+
+  auto ep = std::make_unique<ast::EntryPoint>(ast::PipelineStage::kFragment, "",
+                                              "frag_main");
+  mod.AddEntryPoint(std::move(ep));
+
+  ASSERT_TRUE(td.Determine()) << td.error();
+
+  GeneratorImpl g(&mod);
+  ASSERT_TRUE(g.Generate()) << g.error();
+  EXPECT_EQ(g.result(), R"(#include <metal_stdlib>
+
+float sub_func(device float4& coord, float param) {
+  return coord.x;
+}
+
+fragment void frag_main(device float4& coord [[buffer(0)]]) {
+  float v = sub_func(coord, 1.00000000f);
+  return;
+}
+
+)");
+}
+
 TEST_F(MslGeneratorImplTest, Emit_Function_Called_Two_EntryPoints_WithGlobals) {
   ast::type::VoidType void_type;
   ast::type::F32Type f32;