GLSL: factor out the emission of struct members.

This will be needed for emitting UBO and SSBO interface
blocks.

Bug: tint:1223
Change-Id: I1cdc75b67a4fe612dcf8094a7d73b8bf1f85f40a
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/67242
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Stephen White <senorblanco@chromium.org>

src/writer/glsl/generator_impl.cc

@@ -2450,7 +2450,13 @@ bool GeneratorImpl::EmitTypeAndName(std::ostream& out,
 bool GeneratorImpl::EmitStructType(TextBuffer* b, const sem::Struct* str) {
   auto storage_class_uses = str->StorageClassUsage();
   line(b) << "struct " << StructName(str) << " {";
-  {
+  EmitStructMembers(b, str);
+  line(b) << "};";
+
+  return true;
+}
+
+bool GeneratorImpl::EmitStructMembers(TextBuffer* b, const sem::Struct* str) {
   ScopedIndent si(b);
   for (auto* mem : str->Members()) {
     auto name = builder_.Symbols().NameFor(mem->Name());
@@ -2482,10 +2488,6 @@ bool GeneratorImpl::EmitStructType(TextBuffer* b, const sem::Struct* str) {
     }
     out << post << ";";
   }
-  }
-
-  line(b) << "};";
-
   return true;
 }
 

src/writer/glsl/generator_impl.h

@@ -322,6 +322,11 @@ class GeneratorImpl : public TextGenerator {
   /// @param ty the struct to generate
   /// @returns true if the struct is emitted
   bool EmitStructType(TextBuffer* buffer, const sem::Struct* ty);
+  /// Handles generating the members of a structure
+  /// @param buffer the text buffer that the struct members will be written to
+  /// @param ty the struct to generate
+  /// @returns true if the struct members are emitted
+  bool EmitStructMembers(TextBuffer* buffer, const sem::Struct* ty);
   /// Handles a unary op expression
   /// @param out the output of the expression stream
   /// @param expr the expression to emit