Add support for WGSL writing to BUILD.gn

BUG=tint:49

Change-Id: I4473176d4177a719b7b2659f765b6b467ac43c84
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/19682
Reviewed-by: dan sinclair <dsinclair@google.com>

BUILD.gn

diff --git a/BUILD.gn b/BUILD.gn
index 41e7327..a3b566b 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -38,6 +38,12 @@
   } else {
     defines += [ "TINT_BUILD_WGSL_READER=0" ]
   }
+
+  if (tint_build_wgsl_writer) {
+    defines += [ "TINT_BUILD_WGSL_WRITER=1" ]
+  } else {
+    defines += [ "TINT_BUILD_WGSL_WRITER=0" ]
+  }
 }
 
 # libtint source sets are divided into a non-optional core in :libtint_core and
@@ -302,6 +308,22 @@
   }
 }
 
+source_set("libtint_wgsl_writer") {
+  sources = [
+    "src/writer/wgsl/generator.cc",
+    "src/writer/wgsl/generator.h",
+    "src/writer/wgsl/generator_impl.cc",
+    "src/writer/wgsl/generator_impl.h",
+  ]
+
+  configs += [ ":tint_common_config" ]
+
+  if (build_with_chromium) {
+    configs -= [ "//build/config/compiler:chromium_code" ]
+    configs += [ "//build/config/compiler:no_chromium_code" ]
+  }
+}
+
 source_set("libtint") {
   deps = [ ":libtint_core" ]
 
@@ -317,6 +339,10 @@
     deps += [ ":libtint_wgsl_reader" ]
   }
 
+  if (tint_build_wgsl_writer) {
+    deps += [ ":libtint_wgsl_writer" ]
+  }
+
   configs += [ ":tint_common_config" ]
 
   if (build_with_chromium) {

samples/main.cc

diff --git a/samples/main.cc b/samples/main.cc
index 391380e..e481030 100644
--- a/samples/main.cc
+++ b/samples/main.cc
@@ -356,7 +356,7 @@
 
 #if TINT_BUILD_WGSL_WRITER
   if (options.format == Format::kWgsl) {
-    auto w = static_cast<tint::writer::wgsl::Generator*>(writer.get());
+    auto* w = static_cast<tint::writer::wgsl::Generator*>(writer.get());
     std::cout << w->result() << std::endl;
   }
 #endif  // TINT_BUILD_WGSL_WRITER

src/writer/wgsl/generator_impl.cc

diff --git a/src/writer/wgsl/generator_impl.cc b/src/writer/wgsl/generator_impl.cc
index 88e54c6..1b99cb3 100644
--- a/src/writer/wgsl/generator_impl.cc
+++ b/src/writer/wgsl/generator_impl.cc
@@ -86,7 +86,7 @@
   if (!module.entry_points().empty())
     out_ << std::endl;
 
-  for (const auto& alias : module.alias_types()) {
+  for (auto* const alias : module.alias_types()) {
     if (!EmitAliasType(alias)) {
       return false;
     }
@@ -367,10 +367,10 @@
 
 bool GeneratorImpl::EmitType(ast::type::Type* type) {
   if (type->IsAlias()) {
-    auto alias = type->AsAlias();
+    auto* alias = type->AsAlias();
     out_ << alias->name();
   } else if (type->IsArray()) {
-    auto ary = type->AsArray();
+    auto* ary = type->AsArray();
     out_ << "array<";
     if (!EmitType(ary->type())) {
       return false;
@@ -387,21 +387,21 @@
   } else if (type->IsI32()) {
     out_ << "i32";
   } else if (type->IsMatrix()) {
-    auto mat = type->AsMatrix();
+    auto* mat = type->AsMatrix();
     out_ << "mat" << mat->columns() << "x" << mat->rows() << "<";
     if (!EmitType(mat->type())) {
       return false;
     }
     out_ << ">";
   } else if (type->IsPointer()) {
-    auto ptr = type->AsPointer();
+    auto* ptr = type->AsPointer();
     out_ << "ptr<" << ptr->storage_class() << ", ";
     if (!EmitType(ptr->type())) {
       return false;
     }
     out_ << ">";
   } else if (type->IsStruct()) {
-    auto str = type->AsStruct()->impl();
+    auto* str = type->AsStruct()->impl();
     if (str->decoration() != ast::StructDecoration::kNone) {
       out_ << "[[" << str->decoration() << "]] ";
     }
@@ -440,7 +440,7 @@
   } else if (type->IsU32()) {
     out_ << "u32";
   } else if (type->IsVector()) {
-    auto vec = type->AsVector();
+    auto* vec = type->AsVector();
     out_ << "vec" << vec->size() << "<";
     if (!EmitType(vec->type())) {
       return false;

tint_overrides_with_defaults.gni

diff --git a/tint_overrides_with_defaults.gni b/tint_overrides_with_defaults.gni
index f302f38..5732e2d 100644
--- a/tint_overrides_with_defaults.gni
+++ b/tint_overrides_with_defaults.gni
@@ -51,7 +51,10 @@
     tint_build_wgsl_reader = false
   }
 
-  # TODO(rharrison): Implement support for the reset of the reader/writers
+  # Build the WGSL output writer
+  if (!defined(tint_build_wgsl_writer)) {
+    tint_build_wgsl_writer = false
+  }
 
   # Generate fuzzers
   # TODO(rharrison): Implement fuzzer support