[hlsl-writer] Add binary operator emission.

Emits the binary operators.

Bug: tint:7
Change-Id: I6f4fce3b6fb646b8340e39538b041715a676ac28
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/25164
Reviewed-by: David Neto <dneto@google.com>

BUILD.gn

@@ -1018,6 +1018,7 @@ source_set("tint_unittests_msl_writer_src") {
 
 source_set("tint_unittests_hlsl_writer_src") {
   sources = [
+    "src/writer/hlsl/generator_impl_binary_test.cc",
     "src/writer/hlsl/generator_impl_identifier_test.cc",
     "src/writer/hlsl/generator_impl_test.cc",
     "src/writer/hlsl/namer_test.cc",

src/CMakeLists.txt

@@ -542,6 +542,7 @@ endif()
 
 if (${TINT_BUILD_HLSL_WRITER})
   list(APPEND TINT_TEST_SRCS
+    writer/hlsl/generator_impl_binary_test.cc
     writer/hlsl/generator_impl_identifier_test.cc
     writer/hlsl/generator_impl_test.cc
     writer/hlsl/namer_test.cc

src/writer/hlsl/generator_impl.cc

@@ -14,6 +14,7 @@
 
 #include "src/writer/hlsl/generator_impl.h"
 
+#include "src/ast/binary_expression.h"
 #include "src/ast/identifier_expression.h"
 
 namespace tint {
@@ -52,7 +53,94 @@ std::string GeneratorImpl::current_ep_var_name(VarType type) {
   return name;
 }
 
+bool GeneratorImpl::EmitBinary(ast::BinaryExpression* expr) {
+  out_ << "(";
+
+  if (!EmitExpression(expr->lhs())) {
+    return false;
+  }
+  out_ << " ";
+
+  switch (expr->op()) {
+    case ast::BinaryOp::kAnd:
+      out_ << "&";
+      break;
+    case ast::BinaryOp::kOr:
+      out_ << "|";
+      break;
+    case ast::BinaryOp::kXor:
+      out_ << "^";
+      break;
+    case ast::BinaryOp::kLogicalAnd:
+      // TODO(dsinclair): Implement support ...
+      error_ = "&& not supported yet";
+      return false;
+    case ast::BinaryOp::kLogicalOr:
+      // TODO(dsinclair): Implement support ...
+      error_ = "|| not supported yet";
+      return false;
+    case ast::BinaryOp::kEqual:
+      out_ << "==";
+      break;
+    case ast::BinaryOp::kNotEqual:
+      out_ << "!=";
+      break;
+    case ast::BinaryOp::kLessThan:
+      out_ << "<";
+      break;
+    case ast::BinaryOp::kGreaterThan:
+      out_ << ">";
+      break;
+    case ast::BinaryOp::kLessThanEqual:
+      out_ << "<=";
+      break;
+    case ast::BinaryOp::kGreaterThanEqual:
+      out_ << ">=";
+      break;
+    case ast::BinaryOp::kShiftLeft:
+      out_ << "<<";
+      break;
+    case ast::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 ast::BinaryOp::kAdd:
+      out_ << "+";
+      break;
+    case ast::BinaryOp::kSubtract:
+      out_ << "-";
+      break;
+    case ast::BinaryOp::kMultiply:
+      out_ << "*";
+      break;
+    case ast::BinaryOp::kDivide:
+      out_ << "/";
+      break;
+    case ast::BinaryOp::kModulo:
+      out_ << "%";
+      break;
+    case ast::BinaryOp::kNone:
+      error_ = "missing binary operation type";
+      return false;
+  }
+  out_ << " ";
+
+  if (!EmitExpression(expr->rhs())) {
+    return false;
+  }
+
+  out_ << ")";
+  return true;
+}
+
 bool GeneratorImpl::EmitExpression(ast::Expression* expr) {
+  if (expr->IsBinary()) {
+    return EmitBinary(expr->AsBinary());
+  }
   if (expr->IsIdentifier()) {
     return EmitIdentifier(expr->AsIdentifier());
   }

src/writer/hlsl/generator_impl.h

@@ -35,6 +35,10 @@ class GeneratorImpl : public TextGenerator {
   /// @returns true on successful generation; false otherwise
   bool Generate();
 
+  /// Handles generating a binary expression
+  /// @param expr the binary expression
+  /// @returns true if the expression was emitted, false otherwise
+  bool EmitBinary(ast::BinaryExpression* expr);
   /// Handles generate an Expression
   /// @param expr the expression
   /// @returns true if the expression was emitted

src/writer/hlsl/generator_impl_binary_test.cc

@@ -0,0 +1,76 @@
+// Copyright 2020 The Tint Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <memory>
+
+#include "gtest/gtest.h"
+#include "src/ast/binary_expression.h"
+#include "src/ast/identifier_expression.h"
+#include "src/ast/module.h"
+#include "src/writer/hlsl/generator_impl.h"
+
+namespace tint {
+namespace writer {
+namespace hlsl {
+namespace {
+
+struct BinaryData {
+  const char* result;
+  ast::BinaryOp op;
+};
+inline std::ostream& operator<<(std::ostream& out, BinaryData data) {
+  out << data.op;
+  return out;
+}
+using HlslBinaryTest = testing::TestWithParam<BinaryData>;
+TEST_P(HlslBinaryTest, Emit) {
+  auto params = GetParam();
+
+  auto left = std::make_unique<ast::IdentifierExpression>("left");
+  auto right = std::make_unique<ast::IdentifierExpression>("right");
+
+  ast::BinaryExpression expr(params.op, std::move(left), std::move(right));
+
+  ast::Module m;
+  GeneratorImpl g(&m);
+  ASSERT_TRUE(g.EmitExpression(&expr)) << g.error();
+  EXPECT_EQ(g.result(), params.result);
+}
+INSTANTIATE_TEST_SUITE_P(
+    HlslGeneratorImplTest,
+    HlslBinaryTest,
+    testing::Values(
+        BinaryData{"(left & right)", ast::BinaryOp::kAnd},
+        BinaryData{"(left | right)", ast::BinaryOp::kOr},
+        BinaryData{"(left ^ right)", ast::BinaryOp::kXor},
+        // BinaryData{"(left && right)", ast::BinaryOp::kLogicalAnd},
+        // BinaryData{"(left || right)", ast::BinaryOp::kLogicalOr},
+        BinaryData{"(left == right)", ast::BinaryOp::kEqual},
+        BinaryData{"(left != right)", ast::BinaryOp::kNotEqual},
+        BinaryData{"(left < right)", ast::BinaryOp::kLessThan},
+        BinaryData{"(left > right)", ast::BinaryOp::kGreaterThan},
+        BinaryData{"(left <= right)", ast::BinaryOp::kLessThanEqual},
+        BinaryData{"(left >= right)", ast::BinaryOp::kGreaterThanEqual},
+        BinaryData{"(left << right)", ast::BinaryOp::kShiftLeft},
+        BinaryData{"(left >> right)", ast::BinaryOp::kShiftRight},
+        BinaryData{"(left + right)", ast::BinaryOp::kAdd},
+        BinaryData{"(left - right)", ast::BinaryOp::kSubtract},
+        BinaryData{"(left * right)", ast::BinaryOp::kMultiply},
+        BinaryData{"(left / right)", ast::BinaryOp::kDivide},
+        BinaryData{"(left % right)", ast::BinaryOp::kModulo}));
+
+}  // namespace
+}  // namespace hlsl
+}  // namespace writer
+}  // namespace tint