tint: Add Initialize() / Shutdown() public APIs

Have Initialize() bind the Program printer - which is helpful for debugging.
Call these from dawn/node.

This allows dawn/node to print programs when things go wrong.

Change-Id: I32d8805381d2939e82dc6ea383b9860fbb5fb69e
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/107684
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>

include/tint/tint.h

@@ -15,6 +15,9 @@
 #ifndef INCLUDE_TINT_TINT_H_
 #define INCLUDE_TINT_TINT_H_
 
+// Guard for accidental includes to private headers
+#define CURRENTLY_IN_TINT_PUBLIC_HEADER
+
 // TODO(tint:88): When implementing support for an install target, all of these
 //                headers will need to be moved to include/tint/.
 
@@ -64,4 +67,16 @@
 #include "src/tint/writer/glsl/generator.h"
 #endif  // TINT_BUILD_GLSL_WRITER
 
+namespace tint {
+
+/// Initialize initializes the Tint library. Call before using the Tint API.
+void Initialize();
+
+/// Shutdown uninitializes the Tint library. Call after using the Tint API.
+void Shutdown();
+
+}  // namespace tint
+
+#undef CURRENTLY_IN_TINT_PUBLIC_HEADER
+
 #endif  // INCLUDE_TINT_TINT_H_

src/dawn/node/Module.cpp

@@ -20,6 +20,7 @@
 #include "dawn/dawn_proc.h"
 #include "src/dawn/node/binding/Flags.h"
 #include "src/dawn/node/binding/GPU.h"
+#include "tint/tint.h"
 
 namespace {
 Napi::Value CreateGPU(const Napi::CallbackInfo& info) {
@@ -55,7 +56,10 @@ Napi::Value CreateGPU(const Napi::CallbackInfo& info) {
 // types into the global object, and adding the 'create' function on the exported
 // object.
 Napi::Object Initialize(Napi::Env env, Napi::Object exports) {
-    // Begin by setting the Dawn procedure function pointers.
+    // Initialize Tint
+    tint::Initialize();
+
+    // Set all the Dawn procedure function pointers.
     dawnProcSetProcs(&dawn::native::GetProcs());
 
     // Register all the interop types

src/tint/BUILD.gn

@@ -474,6 +474,7 @@ libtint_source_set("libtint_core_all_src") {
     "symbol_table.h",
     "text/unicode.cc",
     "text/unicode.h",
+    "tint.cc",
     "traits.h",
     "transform/add_block_attribute.cc",
     "transform/add_block_attribute.h",

src/tint/CMakeLists.txt

@@ -385,6 +385,7 @@ set(TINT_LIB_SRCS
   symbol_table.h
   symbol.cc
   symbol.h
+  tint.cc
   text/unicode.cc
   text/unicode.h
   traits.h

src/tint/program_builder.h

@@ -109,7 +109,7 @@
 #include "src/tint/sem/vector.h"
 #include "src/tint/sem/void.h"
 
-#ifdef INCLUDE_TINT_TINT_H_
+#ifdef CURRENTLY_IN_TINT_PUBLIC_HEADER
 #error "internal tint header being #included from tint.h"
 #endif
 

src/tint/test_main.cc

@@ -14,15 +14,12 @@
 
 #include "gmock/gmock.h"
 #include "src/tint/program.h"
+#include "tint/tint.h"
 
 #if TINT_BUILD_SPV_READER
 #include "src/tint/reader/spirv/parser_impl_test_helper.h"
 #endif
 
-#if TINT_BUILD_WGSL_WRITER
-#include "src/tint/writer/wgsl/generator.h"
-#endif
-
 namespace {
 
 void TintInternalCompilerErrorReporter(const tint::diag::List& diagnostics) {
@@ -54,15 +51,7 @@ struct Flags {
 int main(int argc, char** argv) {
     testing::InitGoogleMock(&argc, argv);
 
-#if TINT_BUILD_WGSL_WRITER
+    tint::Initialize();
-    tint::Program::printer = [](const tint::Program* program) {
-        auto result = tint::writer::wgsl::Generate(program, {});
-        if (!result.error.empty()) {
-            return "error: " + result.error;
-        }
-        return result.wgsl;
-    };
-#endif  // TINT_BUILD_WGSL_WRITER
 
     Flags flags;
     if (!flags.parse(argc, argv)) {
@@ -79,5 +68,7 @@ int main(int argc, char** argv) {
 
     auto res = RUN_ALL_TESTS();
 
+    tint::Shutdown();
+
     return res;
 }

src/tint/tint.cc

@@ -0,0 +1,36 @@
+// Copyright 2022 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 "tint/tint.h"
+
+namespace tint {
+
+void Initialize() {
+#if TINT_BUILD_WGSL_WRITER
+    // Register the Program printer. This is used for debugging purposes.
+    tint::Program::printer = [](const tint::Program* program) {
+        auto result = writer::wgsl::Generate(program, {});
+        if (!result.error.empty()) {
+            return "error: " + result.error;
+        }
+        return result.wgsl;
+    };
+#endif
+}
+
+void Shutdown() {
+    // Currently no-op, but may release tint resources in the future.
+}
+
+}  // namespace tint