[spirv-reader] Emit function variable initializers

Bug: tint:3
Change-Id: I1c7fa2c282e6dd95ea048df83f608d4462150394
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/18820
Reviewed-by: dan sinclair <dsinclair@google.com>

src/reader/spirv/function.cc

@@ -18,6 +18,11 @@
 #include "source/opt/function.h"
 #include "source/opt/instruction.h"
 #include "source/opt/module.h"
+#include "src/ast/bool_literal.h"
+#include "src/ast/float_literal.h"
+#include "src/ast/int_literal.h"
+#include "src/ast/scalar_constructor_expression.h"
+#include "src/ast/uint_literal.h"
 #include "src/ast/variable.h"
 #include "src/ast/variable_decl_statement.h"
 #include "src/reader/spirv/fail_stream.h"
@@ -32,6 +37,8 @@ FunctionEmitter::FunctionEmitter(ParserImpl* pi,
     : parser_impl_(*pi),
       ast_module_(pi->get_module()),
       ir_context_(*(pi->ir_context())),
+      def_use_mgr_(ir_context_.get_def_use_mgr()),
+      constant_mgr_(ir_context_.get_constant_mgr()),
       type_mgr_(ir_context_.get_type_mgr()),
       fail_stream_(pi->fail_stream()),
       namer_(pi->namer()),
@@ -142,6 +149,13 @@ bool FunctionEmitter::EmitFunctionVariables() {
     auto var =
         parser_impl_.MakeVariable(inst.result_id(),
                                   ast::StorageClass::kNone, var_store_type);
+    if (inst.NumInOperands() > 1) {
+      // SPIR-V initializers are always constants.
+      // (OpenCL also allows the ID of an OpVariable, but we don't handle that
+      // here.)
+      var->set_constructor(
+          parser_impl_.MakeConstantExpression(inst.GetSingleWordInOperand(1)));
+    }
     // TODO(dneto): Add the initializer via Variable::set_constructor.
     auto var_decl_stmt = std::make_unique<ast::VariableDeclStatement>(std::move(var));
     ast_body_.emplace_back(std::move(var_decl_stmt));

src/reader/spirv/function.h

@@ -15,9 +15,11 @@
 #ifndef SRC_READER_SPIRV_FUNCTION_H_
 #define SRC_READER_SPIRV_FUNCTION_H_
 
+#include "source/opt/constants.h"
 #include "source/opt/function.h"
 #include "source/opt/ir_context.h"
 #include "source/opt/type_manager.h"
+#include "src/ast/expression.h"
 #include "src/ast/module.h"
 #include "src/reader/spirv/fail_stream.h"
 #include "src/reader/spirv/namer.h"
@@ -73,6 +75,8 @@ class FunctionEmitter {
   ParserImpl& parser_impl_;
   ast::Module& ast_module_;
   spvtools::opt::IRContext& ir_context_;
+  spvtools::opt::analysis::DefUseManager* def_use_mgr_;
+  spvtools::opt::analysis::ConstantManager* constant_mgr_;
   spvtools::opt::analysis::TypeManager* type_mgr_;
   FailStream& fail_stream_;
   Namer& namer_;

src/reader/spirv/function_var_test.cc

@@ -43,13 +43,30 @@ std::string CommonTypes() {
   return R"(
     %void = OpTypeVoid
     %voidfn = OpTypeFunction %void
+
+    %bool = OpTypeBool
     %float = OpTypeFloat 32
     %uint = OpTypeInt 32 0
     %int = OpTypeInt 32 1
-    %float_0 = OpConstant %float 0.0
+
+    %ptr_bool = OpTypePointer Function %bool
     %ptr_float = OpTypePointer Function %float
     %ptr_uint = OpTypePointer Function %uint
     %ptr_int = OpTypePointer Function %int
+
+    %true = OpConstantTrue %bool
+    %false = OpConstantFalse %bool
+    %float_0 = OpConstant %float 0.0
+    %float_1p5 = OpConstant %float 1.5
+    %uint_1 = OpConstant %uint 1
+    %int_m1 = OpConstant %int -1
+    %uint_2 = OpConstant %uint 2
+
+    %v2float = OpTypeVector %float 2
+    %m3v2float = OpTypeMatrix %v2float 3
+
+    %arr2uint = OpTypeArray %uint %uint_2
+    %strct = OpTypeStruct %uint %float %arr2uint
   )";
 }
 
@@ -167,6 +184,296 @@ VariableDeclStatement{
 )"));
 }
 
+TEST_F(SpvParserTest, EmitFunctionVariables_ScalarInitializers) {
+  auto p = parser(
+      test::Assemble(Names({"a", "b", "c", "d", "e"}) + CommonTypes() + R"(
+     %100 = OpFunction %void None %voidfn
+     %entry = OpLabel
+     %a = OpVariable %ptr_bool Function %true
+     %b = OpVariable %ptr_bool Function %false
+     %c = OpVariable %ptr_int Function %int_m1
+     %d = OpVariable %ptr_uint Function %uint_1
+     %e = OpVariable %ptr_float Function %float_1p5
+     OpReturn
+     OpFunctionEnd
+  )"));
+  ASSERT_TRUE(p->BuildAndParseInternalModuleExceptFunctions());
+  FunctionEmitter fe(p, *spirv_function(100));
+  EXPECT_TRUE(fe.EmitFunctionVariables());
+
+  EXPECT_THAT(ToString(fe.ast_body()), HasSubstr(R"(VariableDeclStatement{
+  Variable{
+    a
+    none
+    __bool
+    {
+      ScalarConstructor{true}
+    }
+  }
+}
+VariableDeclStatement{
+  Variable{
+    b
+    none
+    __bool
+    {
+      ScalarConstructor{false}
+    }
+  }
+}
+VariableDeclStatement{
+  Variable{
+    c
+    none
+    __i32
+    {
+      ScalarConstructor{-1}
+    }
+  }
+}
+VariableDeclStatement{
+  Variable{
+    d
+    none
+    __u32
+    {
+      ScalarConstructor{1}
+    }
+  }
+}
+VariableDeclStatement{
+  Variable{
+    e
+    none
+    __f32
+    {
+      ScalarConstructor{1.500000}
+    }
+  }
+}
+)"));
+}
+
+TEST_F(SpvParserTest, EmitFunctionVariables_ScalarNullInitializers) {
+  auto p =
+      parser(test::Assemble(Names({"a", "b", "c", "d"}) + CommonTypes() + R"(
+     %null_bool = OpConstantNull %bool
+     %null_int = OpConstantNull %int
+     %null_uint = OpConstantNull %uint
+     %null_float = OpConstantNull %float
+
+     %100 = OpFunction %void None %voidfn
+     %entry = OpLabel
+     %a = OpVariable %ptr_bool Function %null_bool
+     %b = OpVariable %ptr_int Function %null_int
+     %c = OpVariable %ptr_uint Function %null_uint
+     %d = OpVariable %ptr_float Function %null_float
+     OpReturn
+     OpFunctionEnd
+  )"));
+  ASSERT_TRUE(p->BuildAndParseInternalModuleExceptFunctions()) << p->error();
+  FunctionEmitter fe(p, *spirv_function(100));
+  EXPECT_TRUE(fe.EmitFunctionVariables());
+
+  EXPECT_THAT(ToString(fe.ast_body()), HasSubstr(R"(VariableDeclStatement{
+  Variable{
+    a
+    none
+    __bool
+    {
+      ScalarConstructor{false}
+    }
+  }
+}
+VariableDeclStatement{
+  Variable{
+    b
+    none
+    __i32
+    {
+      ScalarConstructor{0}
+    }
+  }
+}
+VariableDeclStatement{
+  Variable{
+    c
+    none
+    __u32
+    {
+      ScalarConstructor{0}
+    }
+  }
+}
+VariableDeclStatement{
+  Variable{
+    d
+    none
+    __f32
+    {
+      ScalarConstructor{0.000000}
+    }
+  }
+}
+)"));
+}
+
+TEST_F(SpvParserTest, EmitFunctionVariables_VectorInitializer) {
+  auto p = parser(test::Assemble(CommonTypes() + R"(
+     %ptr = OpTypePointer Function %v2float
+     %two = OpConstant %float 2.0
+     %const = OpConstantComposite %v2float %float_1p5 %two
+
+     %100 = OpFunction %void None %voidfn
+     %entry = OpLabel
+     %200 = OpVariable %ptr Function %const
+     OpReturn
+     OpFunctionEnd
+  )"));
+  ASSERT_TRUE(p->BuildAndParseInternalModuleExceptFunctions());
+  FunctionEmitter fe(p, *spirv_function(100));
+  EXPECT_TRUE(fe.EmitFunctionVariables());
+
+  EXPECT_THAT(ToString(fe.ast_body()), HasSubstr(R"(VariableDeclStatement{
+  Variable{
+    x_200
+    none
+    __vec_2__f32
+    {
+      TypeConstructor{
+        __vec_2__f32
+        ScalarConstructor{1.500000}
+        ScalarConstructor{2.000000}
+      }
+    }
+  }
+}
+)")) << ToString(fe.ast_body());
+}
+
+TEST_F(SpvParserTest, EmitFunctionVariables_MatrixInitializer) {
+  auto p = parser(test::Assemble(CommonTypes() + R"(
+     %ptr = OpTypePointer Function %m3v2float
+     %two = OpConstant %float 2.0
+     %three = OpConstant %float 3.0
+     %four = OpConstant %float 4.0
+     %v0 = OpConstantComposite %v2float %float_1p5 %two
+     %v1 = OpConstantComposite %v2float %two %three
+     %v2 = OpConstantComposite %v2float %three %four
+     %const = OpConstantComposite %m3v2float %v0 %v1 %v2
+
+     %100 = OpFunction %void None %voidfn
+     %entry = OpLabel
+     %200 = OpVariable %ptr Function %const
+     OpReturn
+     OpFunctionEnd
+  )"));
+  ASSERT_TRUE(p->BuildAndParseInternalModuleExceptFunctions());
+  FunctionEmitter fe(p, *spirv_function(100));
+  EXPECT_TRUE(fe.EmitFunctionVariables());
+
+  EXPECT_THAT(ToString(fe.ast_body()), HasSubstr(R"(VariableDeclStatement{
+  Variable{
+    x_200
+    none
+    __mat_2_3__f32
+    {
+      TypeConstructor{
+        __mat_2_3__f32
+        TypeConstructor{
+          __vec_2__f32
+          ScalarConstructor{1.500000}
+          ScalarConstructor{2.000000}
+        }
+        TypeConstructor{
+          __vec_2__f32
+          ScalarConstructor{2.000000}
+          ScalarConstructor{3.000000}
+        }
+        TypeConstructor{
+          __vec_2__f32
+          ScalarConstructor{3.000000}
+          ScalarConstructor{4.000000}
+        }
+      }
+    }
+  }
+}
+)"));
+}
+
+TEST_F(SpvParserTest, EmitFunctionVariables_ArrayInitializer) {
+  auto p = parser(test::Assemble(CommonTypes() + R"(
+     %ptr = OpTypePointer Function %arr2uint
+     %two = OpConstant %uint 2
+     %const = OpConstantComposite %arr2uint %uint_1 %two
+
+     %100 = OpFunction %void None %voidfn
+     %entry = OpLabel
+     %200 = OpVariable %ptr Function %const
+     OpReturn
+     OpFunctionEnd
+  )"));
+  ASSERT_TRUE(p->BuildAndParseInternalModuleExceptFunctions());
+  FunctionEmitter fe(p, *spirv_function(100));
+  EXPECT_TRUE(fe.EmitFunctionVariables());
+
+  EXPECT_THAT(ToString(fe.ast_body()), HasSubstr(R"(VariableDeclStatement{
+  Variable{
+    x_200
+    none
+    __array__u32_2
+    {
+      TypeConstructor{
+        __array__u32_2
+        ScalarConstructor{1}
+        ScalarConstructor{2}
+      }
+    }
+  }
+}
+)"));
+}
+
+TEST_F(SpvParserTest, EmitFunctionVariables_StructInitializer) {
+  auto p = parser(test::Assemble(CommonTypes() + R"(
+     %ptr = OpTypePointer Function %strct
+     %two = OpConstant %uint 2
+     %arrconst = OpConstantComposite %arr2uint %uint_1 %two
+     %const = OpConstantComposite %strct %uint_1 %float_1p5 %arrconst
+
+     %100 = OpFunction %void None %voidfn
+     %entry = OpLabel
+     %200 = OpVariable %ptr Function %const
+     OpReturn
+     OpFunctionEnd
+  )"));
+  ASSERT_TRUE(p->BuildAndParseInternalModuleExceptFunctions());
+  FunctionEmitter fe(p, *spirv_function(100));
+  EXPECT_TRUE(fe.EmitFunctionVariables());
+
+  EXPECT_THAT(ToString(fe.ast_body()), HasSubstr(R"(VariableDeclStatement{
+  Variable{
+    x_200
+    none
+    __struct_S
+    {
+      TypeConstructor{
+        __struct_S
+        ScalarConstructor{1}
+        ScalarConstructor{1.500000}
+        TypeConstructor{
+          __array__u32_2
+          ScalarConstructor{1}
+          ScalarConstructor{2}
+        }
+      }
+    }
+  }
+}
+)"));
+}
+
 }  // namespace
 }  // namespace spirv
 }  // namespace reader

src/reader/spirv/parser_impl.cc

@@ -25,6 +25,7 @@
 
 #include "source/opt/basic_block.h"
 #include "source/opt/build_module.h"
+#include "source/opt/constants.h"
 #include "source/opt/decoration_manager.h"
 #include "source/opt/function.h"
 #include "source/opt/instruction.h"
@@ -32,8 +33,12 @@
 #include "source/opt/type_manager.h"
 #include "source/opt/types.h"
 #include "spirv-tools/libspirv.hpp"
+#include "src/ast/bool_literal.h"
 #include "src/ast/builtin_decoration.h"
 #include "src/ast/decorated_variable.h"
+#include "src/ast/float_literal.h"
+#include "src/ast/int_literal.h"
+#include "src/ast/scalar_constructor_expression.h"
 #include "src/ast/struct.h"
 #include "src/ast/struct_decoration.h"
 #include "src/ast/struct_member.h"
@@ -51,6 +56,8 @@
 #include "src/ast/type/u32_type.h"
 #include "src/ast/type/vector_type.h"
 #include "src/ast/type/void_type.h"
+#include "src/ast/type_constructor_expression.h"
+#include "src/ast/uint_literal.h"
 #include "src/ast/variable.h"
 #include "src/ast/variable_decl_statement.h"
 #include "src/ast/variable_decoration.h"
@@ -750,6 +757,80 @@ std::unique_ptr<ast::Variable> ParserImpl::MakeVariable(uint32_t id,
   return ast_var;
 }
 
+std::unique_ptr<ast::Expression> ParserImpl::MakeConstantExpression(
+    uint32_t id) {
+  if (!success_) {
+    return nullptr;
+  }
+  const auto* inst = def_use_mgr_->GetDef(id);
+  if (inst == nullptr) {
+    Fail() << "ID " << id << " is not a registered instruction";
+    return nullptr;
+  }
+  auto* ast_type = ConvertType(inst->type_id());
+  if (ast_type == nullptr) {
+    return nullptr;
+  }
+  // TODO(dneto): Handle spec constants too?
+  const auto* spirv_const = constant_mgr_->FindDeclaredConstant(id);
+  if (spirv_const == nullptr) {
+    Fail() << "ID " << id << " is not a constant";
+    return nullptr;
+  }
+  // TODO(dneto): Note: NullConstant for int, uint, float map to a regular 0.
+  // So canonicalization should map that way too.
+  // Currently "null<type>" is missing from the WGSL parser.
+  // See https://bugs.chromium.org/p/tint/issues/detail?id=34
+  if (ast_type->IsU32()) {
+    return std::make_unique<ast::ScalarConstructorExpression>(
+        std::make_unique<ast::UintLiteral>(ast_type, spirv_const->GetU32()));
+  }
+  if (ast_type->IsI32()) {
+    return std::make_unique<ast::ScalarConstructorExpression>(
+        std::make_unique<ast::IntLiteral>(ast_type, spirv_const->GetS32()));
+  }
+  if (ast_type->IsF32()) {
+    return std::make_unique<ast::ScalarConstructorExpression>(
+        std::make_unique<ast::FloatLiteral>(ast_type, spirv_const->GetFloat()));
+  }
+  if (ast_type->IsBool()) {
+    const bool value = spirv_const->AsNullConstant() ? false :
+      spirv_const->AsBoolConstant()->value();
+    return std::make_unique<ast::ScalarConstructorExpression>(
+        std::make_unique<ast::BoolLiteral>(
+            ast_type, value));
+  }
+  auto spirv_composite_const = spirv_const->AsCompositeConstant();
+  if (spirv_composite_const != nullptr) {
+    // Handle vector, matrix, array, and struct
+
+    // TODO(dneto): Handle the spirv_composite_const->IsZero() case specially.
+    // See https://github.com/gpuweb/gpuweb/issues/685
+
+    // Generate a composite from explicit components.
+    ast::ExpressionList ast_components;
+    for (const auto* component : spirv_composite_const->GetComponents()) {
+      auto* def = constant_mgr_->GetDefiningInstruction(component);
+      if (def == nullptr) {
+        Fail() << "internal error: SPIR-V constant doesn't have defining "
+                  "instruction";
+        return nullptr;
+      }
+      auto ast_component = MakeConstantExpression(def->result_id());
+      if (!success_) {
+        // We've already emitted a diagnostic.
+        return nullptr;
+      }
+      ast_components.emplace_back(std::move(ast_component));
+    }
+    return std::make_unique<ast::TypeConstructorExpression>(
+        ast_type, std::move(ast_components));
+  }
+  Fail() << "Unhandled constant type " << inst->type_id() << " for value ID "
+         << id;
+  return nullptr;
+}
+
 bool ParserImpl::EmitFunctions() {
   if (!success_) {
     return false;

src/reader/spirv/parser_impl.h

@@ -221,6 +221,11 @@ class ParserImpl : Reader {
                                               ast::StorageClass sc,
                                               ast::type::Type* type);
 
+  /// Creates an AST expression node for a SPIR-V constant.
+  /// @param id the SPIR-V ID of the constant
+  /// @returns a new Literal node
+  std::unique_ptr<ast::Expression> MakeConstantExpression(uint32_t id);
+
  private:
   /// Converts a specific SPIR-V type to a Tint type. Integer case
   ast::type::Type* ConvertType(const spvtools::opt::analysis::Integer* int_ty);