[type-determiner][spirv-writer] Add arrayLength support

This CL adds support for retrieving the array length of a Runtime Array
in the SPIR-V backend.

Bug: tint:252
Change-Id: Ic13c4a99da5760738d57702c45f52c6a194a172d
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/29220
Commit-Queue: David Neto <dneto@google.com>
Reviewed-by: David Neto <dneto@google.com>

src/ast/intrinsic.cc

@@ -31,6 +31,9 @@ std::ostream& operator<<(std::ostream& out, Intrinsic i) {
     case Intrinsic::kAny:
       out << "any";
       break;
+    case Intrinsic::kArrayLength:
+      out << "arrayLength";
+      break;
     case Intrinsic::kAsin:
       out << "asin";
       break;

src/ast/intrinsic.h

@@ -28,6 +28,7 @@ enum class Intrinsic {
   kAcos,
   kAll,
   kAny,
+  kArrayLength,
   kAsin,
   kAtan,
   kAtan2,

src/type_determiner.cc

@@ -520,6 +520,11 @@ bool TypeDeterminer::DetermineIntrinsic(ast::IdentifierExpression* ident,
         ctx_.type_mgr().Get(std::make_unique<ast::type::BoolType>()));
     return true;
   }
+  if (ident->intrinsic() == ast::Intrinsic::kArrayLength) {
+    expr->func()->set_result_type(
+        ctx_.type_mgr().Get(std::make_unique<ast::type::U32Type>()));
+    return true;
+  }
   if (ast::intrinsic::IsFloatClassificationIntrinsic(ident->intrinsic())) {
     if (expr->params().size() != 1) {
       set_error(expr->source(),
@@ -638,6 +643,7 @@ bool TypeDeterminer::DetermineIntrinsic(ast::IdentifierExpression* ident,
     }
   }
   if (data == nullptr) {
+    error_ = "unable to find intrinsic " + ident->name();
     return false;
   }
 
@@ -788,6 +794,8 @@ void TypeDeterminer::SetIntrinsicIfNeeded(ast::IdentifierExpression* ident) {
     ident->set_intrinsic(ast::Intrinsic::kAll);
   } else if (ident->name() == "any") {
     ident->set_intrinsic(ast::Intrinsic::kAny);
+  } else if (ident->name() == "arrayLength") {
+    ident->set_intrinsic(ast::Intrinsic::kArrayLength);
   } else if (ident->name() == "asin") {
     ident->set_intrinsic(ast::Intrinsic::kAsin);
   } else if (ident->name() == "atan") {

src/type_determiner_test.cc

@@ -2494,6 +2494,7 @@ INSTANTIATE_TEST_SUITE_P(
         IntrinsicData{"acos", ast::Intrinsic::kAcos},
         IntrinsicData{"all", ast::Intrinsic::kAll},
         IntrinsicData{"any", ast::Intrinsic::kAny},
+        IntrinsicData{"arrayLength", ast::Intrinsic::kArrayLength},
         IntrinsicData{"asin", ast::Intrinsic::kAsin},
         IntrinsicData{"atan", ast::Intrinsic::kAtan},
         IntrinsicData{"atan2", ast::Intrinsic::kAtan2},

src/writer/spirv/builder.cc

@@ -1670,6 +1670,37 @@ uint32_t Builder::GenerateIntrinsic(ast::IdentifierExpression* ident,
     op = spv::Op::OpAny;
   } else if (intrinsic == ast::Intrinsic::kAll) {
     op = spv::Op::OpAll;
+  } else if (intrinsic == ast::Intrinsic::kArrayLength) {
+    if (call->params().empty()) {
+      error_ = "missing param for runtime array length";
+      return 0;
+    } else if (!call->params()[0]->IsMemberAccessor()) {
+      if (call->params()[0]->result_type()->IsPointer()) {
+        error_ = "pointer accessors not supported yet";
+      } else {
+        error_ = "invalid accessor for runtime array length";
+      }
+      return 0;
+    }
+    auto* accessor = call->params()[0]->AsMemberAccessor();
+    auto struct_id = GenerateExpression(accessor->structure());
+    if (struct_id == 0) {
+      return 0;
+    }
+    params.push_back(Operand::Int(struct_id));
+
+    auto* type = accessor->structure()->result_type()->UnwrapAliasPtrAlias();
+    if (!type->IsStruct()) {
+      error_ =
+          "invalid type (" + type->type_name() + ") for runtime array length";
+      return 0;
+    }
+    // Runtime array must be the last member in the structure
+    params.push_back(
+        Operand::Int(uint32_t(type->AsStruct()->impl()->members().size() - 1)));
+
+    push_function_inst(spv::Op::OpArrayLength, params);
+    return result_id;
   } else if (intrinsic == ast::Intrinsic::kCountOneBits) {
     op = spv::Op::OpBitCount;
   } else if (intrinsic == ast::Intrinsic::kDot) {

src/writer/spirv/builder_intrinsic_test.cc

@@ -18,16 +18,22 @@
 #include "src/ast/call_expression.h"
 #include "src/ast/float_literal.h"
 #include "src/ast/identifier_expression.h"
+#include "src/ast/member_accessor_expression.h"
 #include "src/ast/scalar_constructor_expression.h"
 #include "src/ast/sint_literal.h"
+#include "src/ast/struct.h"
+#include "src/ast/struct_member.h"
+#include "src/ast/type/array_type.h"
 #include "src/ast/type/bool_type.h"
 #include "src/ast/type/depth_texture_type.h"
 #include "src/ast/type/f32_type.h"
 #include "src/ast/type/i32_type.h"
 #include "src/ast/type/matrix_type.h"
 #include "src/ast/type/multisampled_texture_type.h"
+#include "src/ast/type/pointer_type.h"
 #include "src/ast/type/sampled_texture_type.h"
 #include "src/ast/type/sampler_type.h"
+#include "src/ast/type/struct_type.h"
 #include "src/ast/type/u32_type.h"
 #include "src/ast/type/vector_type.h"
 #include "src/ast/type/void_type.h"
@@ -2716,6 +2722,181 @@ OpFunctionEnd
 )");
 }
 
+TEST_F(BuilderTest, Call_ArrayLength) {
+  ast::type::F32Type f32;
+  ast::type::VoidType void_type;
+  ast::type::ArrayType ary(&f32);
+
+  ast::StructMemberDecorationList decos;
+  ast::StructMemberList members;
+  members.push_back(
+      std::make_unique<ast::StructMember>("a", &ary, std::move(decos)));
+
+  auto s = std::make_unique<ast::Struct>(ast::StructDecoration::kNone,
+                                         std::move(members));
+  ast::type::StructType s_type(std::move(s));
+  s_type.set_name("my_struct");
+
+  auto var = std::make_unique<ast::Variable>("b", ast::StorageClass::kPrivate,
+                                             &s_type);
+
+  ast::ExpressionList params;
+  params.push_back(std::make_unique<ast::MemberAccessorExpression>(
+      std::make_unique<ast::IdentifierExpression>("b"),
+      std::make_unique<ast::IdentifierExpression>("a")));
+
+  ast::CallExpression expr(
+      std::make_unique<ast::IdentifierExpression>("arrayLength"),
+      std::move(params));
+
+  Context ctx;
+  ast::Module mod;
+  TypeDeterminer td(&ctx, &mod);
+  td.RegisterVariableForTesting(var.get());
+
+  ASSERT_TRUE(td.DetermineResultType(&expr)) << td.error();
+
+  ast::Function func("a_func", {}, &void_type);
+
+  Builder b(&mod);
+  ASSERT_TRUE(b.GenerateFunction(&func)) << b.error();
+  ASSERT_TRUE(b.GenerateGlobalVariable(var.get())) << b.error();
+  EXPECT_EQ(b.GenerateExpression(&expr), 11u) << b.error();
+
+  EXPECT_EQ(DumpInstructions(b.types()),
+            R"(%2 = OpTypeVoid
+%1 = OpTypeFunction %2
+%9 = OpTypeFloat 32
+%8 = OpTypeRuntimeArray %9
+%7 = OpTypeStruct %8
+%6 = OpTypePointer Private %7
+%10 = OpConstantNull %7
+%5 = OpVariable %6 Private %10
+%12 = OpTypeInt 32 0
+)");
+
+  EXPECT_EQ(DumpInstructions(b.functions()[0].instructions()),
+            R"(%11 = OpArrayLength %12 %5 0
+)");
+}
+
+TEST_F(BuilderTest, Call_ArrayLength_OtherMembersInStruct) {
+  ast::type::F32Type f32;
+  ast::type::VoidType void_type;
+  ast::type::ArrayType ary(&f32);
+
+  ast::StructMemberDecorationList decos;
+  ast::StructMemberList members;
+  members.push_back(
+      std::make_unique<ast::StructMember>("z", &f32, std::move(decos)));
+  members.push_back(
+      std::make_unique<ast::StructMember>("a", &ary, std::move(decos)));
+
+  auto s = std::make_unique<ast::Struct>(ast::StructDecoration::kNone,
+                                         std::move(members));
+  ast::type::StructType s_type(std::move(s));
+  s_type.set_name("my_struct");
+
+  auto var = std::make_unique<ast::Variable>("b", ast::StorageClass::kPrivate,
+                                             &s_type);
+
+  ast::ExpressionList params;
+  params.push_back(std::make_unique<ast::MemberAccessorExpression>(
+      std::make_unique<ast::IdentifierExpression>("b"),
+      std::make_unique<ast::IdentifierExpression>("a")));
+
+  ast::CallExpression expr(
+      std::make_unique<ast::IdentifierExpression>("arrayLength"),
+      std::move(params));
+
+  Context ctx;
+  ast::Module mod;
+  TypeDeterminer td(&ctx, &mod);
+  td.RegisterVariableForTesting(var.get());
+
+  ASSERT_TRUE(td.DetermineResultType(&expr)) << td.error();
+
+  ast::Function func("a_func", {}, &void_type);
+
+  Builder b(&mod);
+  ASSERT_TRUE(b.GenerateFunction(&func)) << b.error();
+  ASSERT_TRUE(b.GenerateGlobalVariable(var.get())) << b.error();
+  EXPECT_EQ(b.GenerateExpression(&expr), 11u) << b.error();
+
+  EXPECT_EQ(DumpInstructions(b.types()),
+            R"(%2 = OpTypeVoid
+%1 = OpTypeFunction %2
+%8 = OpTypeFloat 32
+%9 = OpTypeRuntimeArray %8
+%7 = OpTypeStruct %8 %9
+%6 = OpTypePointer Private %7
+%10 = OpConstantNull %7
+%5 = OpVariable %6 Private %10
+%12 = OpTypeInt 32 0
+)");
+
+  EXPECT_EQ(DumpInstructions(b.functions()[0].instructions()),
+            R"(%11 = OpArrayLength %12 %5 1
+)");
+}
+
+// TODO(dsinclair): https://bugs.chromium.org/p/tint/issues/detail?id=266
+TEST_F(BuilderTest, DISABLED_Call_ArrayLength_Ptr) {
+  ast::type::F32Type f32;
+  ast::type::VoidType void_type;
+  ast::type::ArrayType ary(&f32);
+  ast::type::PointerType ptr(&ary, ast::StorageClass::kStorageBuffer);
+
+  ast::StructMemberDecorationList decos;
+  ast::StructMemberList members;
+  members.push_back(
+      std::make_unique<ast::StructMember>("z", &f32, std::move(decos)));
+  members.push_back(
+      std::make_unique<ast::StructMember>("a", &ary, std::move(decos)));
+
+  auto s = std::make_unique<ast::Struct>(ast::StructDecoration::kNone,
+                                         std::move(members));
+  ast::type::StructType s_type(std::move(s));
+  s_type.set_name("my_struct");
+
+  auto var = std::make_unique<ast::Variable>("b", ast::StorageClass::kPrivate,
+                                             &s_type);
+
+  auto ptr_var = std::make_unique<ast::Variable>(
+      "ptr_var", ast::StorageClass::kPrivate, &ptr);
+  ptr_var->set_constructor(std::make_unique<ast::MemberAccessorExpression>(
+      std::make_unique<ast::IdentifierExpression>("b"),
+      std::make_unique<ast::IdentifierExpression>("a")));
+
+  ast::ExpressionList params;
+  params.push_back(std::make_unique<ast::IdentifierExpression>("ptr_var"));
+
+  ast::CallExpression expr(
+      std::make_unique<ast::IdentifierExpression>("arrayLength"),
+      std::move(params));
+
+  Context ctx;
+  ast::Module mod;
+  TypeDeterminer td(&ctx, &mod);
+  td.RegisterVariableForTesting(var.get());
+  td.RegisterVariableForTesting(ptr_var.get());
+
+  ASSERT_TRUE(td.DetermineResultType(&expr)) << td.error();
+
+  ast::Function func("a_func", {}, &void_type);
+
+  Builder b(&mod);
+  ASSERT_TRUE(b.GenerateFunction(&func)) << b.error();
+  ASSERT_TRUE(b.GenerateGlobalVariable(var.get())) << b.error();
+  EXPECT_EQ(b.GenerateExpression(&expr), 11u) << b.error();
+
+  EXPECT_EQ(DumpInstructions(b.types()), R"( ... )");
+
+  EXPECT_EQ(DumpInstructions(b.functions()[0].instructions()),
+            R"(%11 = OpArrayLength %12 %5 1
+)");
+}
+
 }  // namespace
 }  // namespace spirv
 }  // namespace writer