From 59fc026bcf32e3c5fdf5febc4004f71dc20df89e Mon Sep 17 00:00:00 2001
From: dan sinclair <dsinclair@google.com>
Date: Mon, 1 Jun 2020 13:44:43 +0000
Subject: [PATCH] [spirv-writer] Generate kill statements.

This Cl adds preliminary support for generating Kill commands. This may
change in the future if the semantics of kill are set in WGSL to not
match OpKill.

Bug: tint:5
Change-Id: Id466a1b26b37867a26373b93f56d627a0491f47f
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/22240
Reviewed-by: David Neto <dneto@google.com>
---
 BUILD.gn                              |  1 +
 src/CMakeLists.txt                    |  1 +
 src/writer/spirv/builder.cc           | 11 +++++++
 src/writer/spirv/builder.h            |  4 +++
 src/writer/spirv/builder_kill_test.cc | 43 +++++++++++++++++++++++++++
 5 files changed, 60 insertions(+)
 create mode 100644 src/writer/spirv/builder_kill_test.cc

diff --git a/BUILD.gn b/BUILD.gn
index 7c08d053b9..73f3454c44 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -688,6 +688,7 @@ source_set("tint_unittests_spv_writer_src") {
     "src/writer/spirv/builder_global_variable_test.cc",
     "src/writer/spirv/builder_ident_expression_test.cc",
     "src/writer/spirv/builder_if_test.cc",
+    "src/writer/spirv/builder_kill_test.cc",
     "src/writer/spirv/builder_literal_test.cc",
     "src/writer/spirv/builder_loop_test.cc",
     "src/writer/spirv/builder_return_test.cc",
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 117063b0a3..2c4745a9c0 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -425,6 +425,7 @@ if(${TINT_BUILD_SPV_WRITER})
     writer/spirv/builder_global_variable_test.cc
     writer/spirv/builder_ident_expression_test.cc
     writer/spirv/builder_if_test.cc
+    writer/spirv/builder_kill_test.cc
     writer/spirv/builder_literal_test.cc
     writer/spirv/builder_loop_test.cc
     writer/spirv/builder_return_test.cc
diff --git a/src/writer/spirv/builder.cc b/src/writer/spirv/builder.cc
index d829a63610..084a50423c 100644
--- a/src/writer/spirv/builder.cc
+++ b/src/writer/spirv/builder.cc
@@ -251,6 +251,14 @@ bool Builder::GenerateContinueStatement(ast::ContinueStatement*) {
   return true;
 }
 
+// TODO(dsinclair): This is generating an OpKill but the semantics of kill
+// haven't been defined for WGSL yet. So, this may need to change.
+// https://github.com/gpuweb/gpuweb/issues/676
+bool Builder::GenerateKillStatement(ast::KillStatement*) {
+  push_function_inst(spv::Op::OpKill, {});
+  return true;
+}
+
 bool Builder::GenerateEntryPoint(ast::EntryPoint* ep) {
   auto name = ep->name();
   if (name.empty()) {
@@ -1405,6 +1413,9 @@ bool Builder::GenerateStatement(ast::Statement* stmt) {
   if (stmt->IsIf()) {
     return GenerateIfStatement(stmt->AsIf());
   }
+  if (stmt->IsKill()) {
+    return GenerateKillStatement(stmt->AsKill());
+  }
   if (stmt->IsLoop()) {
     return GenerateLoopStatement(stmt->AsLoop());
   }
diff --git a/src/writer/spirv/builder.h b/src/writer/spirv/builder.h
index 2754b7fa45..a8433e65fa 100644
--- a/src/writer/spirv/builder.h
+++ b/src/writer/spirv/builder.h
@@ -194,6 +194,10 @@ class Builder {
   /// @param stmt the statement to generate
   /// @returns true if the statement was successfully generated
   bool GenerateContinueStatement(ast::ContinueStatement* stmt);
+  /// Generates a kill statement
+  /// @param stmt the statement to generate
+  /// @returns true if the statement was successfully generated
+  bool GenerateKillStatement(ast::KillStatement* stmt);
   /// Generates an entry point instruction
   /// @param ep the entry point
   /// @returns true if the instruction was generated, false otherwise
diff --git a/src/writer/spirv/builder_kill_test.cc b/src/writer/spirv/builder_kill_test.cc
new file mode 100644
index 0000000000..23437c3441
--- /dev/null
+++ b/src/writer/spirv/builder_kill_test.cc
@@ -0,0 +1,43 @@
+// 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 "gtest/gtest.h"
+#include "src/ast/kill_statement.h"
+#include "src/context.h"
+#include "src/type_determiner.h"
+#include "src/writer/spirv/builder.h"
+#include "src/writer/spirv/spv_dump.h"
+
+namespace tint {
+namespace writer {
+namespace spirv {
+namespace {
+
+using BuilderTest = testing::Test;
+
+TEST_F(BuilderTest, Kill) {
+  ast::KillStatement expr;
+
+  ast::Module mod;
+  Builder b(&mod);
+  b.push_function(Function{});
+  EXPECT_EQ(b.GenerateKillStatement(&expr), 1u) << b.error();
+  EXPECT_EQ(DumpInstructions(b.functions()[0].instructions()), R"(OpKill
+)");
+}
+
+}  // namespace
+}  // namespace spirv
+}  // namespace writer
+}  // namespace tint
\ No newline at end of file