Have tint executable use the diagnostic printer

Will now print with better formatting and colors on terminals that support it.

Bug: tint:282
Change-Id: Ibff341cb1dc2dcbda6fa0d72e24fdcb172990138
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/31570
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: dan sinclair <dsinclair@chromium.org>

src/reader/reader.h

@@ -19,6 +19,8 @@
 
 #include "src/ast/module.h"
 #include "src/context.h"
+#include "src/diagnostic/diagnostic.h"
+#include "src/diagnostic/formatter.h"
 
 namespace tint {
 namespace reader {
@@ -32,10 +34,17 @@ class Reader {
   /// @returns true if the parse was successful
   virtual bool Parse() = 0;
 
-  /// @returns true if an error was encountered
-  bool has_error() const { return error_.size() > 0; }
+  /// @returns true if an error was encountered.
+  bool has_error() const { return diags_.contains_errors(); }
+
   /// @returns the parser error string
-  const std::string& error() const { return error_; }
+  std::string error() const {
+    diag::Formatter formatter{{false, false, false}};
+    return formatter.format(diags_);
+  }
+
+  /// @returns the full list of diagnostic messages.
+  const diag::List& diagnostics() const { return diags_; }
 
   /// @returns the module. The module in the parser will be reset after this.
   virtual ast::Module module() = 0;
@@ -45,15 +54,15 @@ class Reader {
   /// @param ctx the context object, must be non-null
   explicit Reader(Context* ctx);
 
-  /// Sets the error string
-  /// @param msg the error message
-  void set_error(const std::string& msg) { error_ = msg; }
+  /// Sets the diagnostic messages
+  /// @param diags the list of diagnostic messages
+  void set_diagnostics(const diag::List& diags) { diags_ = diags; }
 
   /// The Tint context object
   Context& ctx_;
 
-  /// An error message, if an error was encountered
-  std::string error_;
+  /// All diagnostic messages from the reader.
+  diag::List diags_;
 };
 
 }  // namespace reader

src/reader/spirv/parser.cc

@@ -27,7 +27,14 @@ Parser::~Parser() = default;
 
 bool Parser::Parse() {
   const auto result = impl_->Parse();
-  set_error(impl_->error());
+  auto err_msg = impl_->error();
+  if (!err_msg.empty()) {
+    // TODO(bclayton): Migrate spirv::ParserImpl to using diagnostics.
+    diag::Diagnostic error{};
+    error.severity = diag::Severity::Error;
+    error.message = err_msg;
+    set_diagnostics({error});
+  }
   return result;
 }
 

src/reader/wgsl/parser.cc

@@ -28,8 +28,7 @@ Parser::~Parser() = default;
 bool Parser::Parse() {
   bool ret = impl_->Parse();
 
-  if (impl_->has_error())
-    set_error(impl_->error());
+  set_diagnostics(std::move(impl_->diagnostics()));
 
   return ret;
 }

src/reader/wgsl/parser_impl.h

@@ -111,6 +111,9 @@ class ParserImpl {
   /// @returns the diagnostic messages
   const diag::List& diagnostics() const { return diags_; }
 
+  /// @returns the diagnostic messages
+  diag::List& diagnostics() { return diags_; }
+
   /// @returns the module. The module in the parser will be reset after this.
   ast::Module module() { return std::move(module_); }