Add diag::List::add_error() helper

Refactors a common pattern in the tint codebase.

Change-Id: Ia8a70d952fd8c204facd0120f24e43ccc9305622
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/38840
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: dan sinclair <dsinclair@chromium.org>

src/diagnostic/diagnostic.h

@@ -98,6 +98,26 @@ class List {
     }
   }
 
+  /// adds the error message without a source to the end of this list.
+  /// @param err_msg the error message
+  void add_error(const std::string& err_msg) {
+    diag::Diagnostic error{};
+    error.severity = diag::Severity::Error;
+    error.message = err_msg;
+    add(std::move(error));
+  }
+
+  /// adds the error message with the given Source to the end of this list.
+  /// @param err_msg the error message
+  /// @param source the source of the error diagnostic
+  void add_error(const std::string& err_msg, const Source& source) {
+    diag::Diagnostic error{};
+    error.severity = diag::Severity::Error;
+    error.source = source;
+    error.message = err_msg;
+    add(std::move(error));
+  }
+
   /// @returns true iff the diagnostic list contains errors diagnostics (or of
   /// higher severity).
   bool contains_errors() const { return error_count_ > 0; }

src/reader/spirv/parser.cc

@@ -14,6 +14,8 @@
 
 #include "src/reader/spirv/parser.h"
 
+#include <utility>
+
 #include "src/reader/spirv/parser_impl.h"
 
 namespace tint {
@@ -30,10 +32,9 @@ bool Parser::Parse() {
   auto err_msg = impl_->error();
   if (!err_msg.empty()) {
     // TODO(bclayton): Migrate spirv::ParserImpl to using diagnostics.
-    diag::Diagnostic error{};
+    diag::List diagnostics;
-    error.severity = diag::Severity::Error;
+    diagnostics.add_error(err_msg);
-    error.message = err_msg;
+    set_diagnostics(std::move(diagnostics));
-    set_diagnostics({error});
   }
   return result;
 }

src/reader/spirv/parser.h

@@ -46,6 +46,7 @@ class Parser : public Reader {
 
  private:
   std::unique_ptr<ParserImpl> impl_;
+  Program program_;
 };
 
 }  // namespace spirv

src/reader/wgsl/parser_impl.cc

@@ -230,11 +230,7 @@ ParserImpl::Failure::Errored ParserImpl::add_error(const Token& t,
 ParserImpl::Failure::Errored ParserImpl::add_error(const Source& source,
                                                    const std::string& err) {
   if (silence_errors_ == 0) {
-    diag::Diagnostic diagnostic;
+    diags_.add_error(err, source);
-    diagnostic.severity = diag::Severity::Error;
-    diagnostic.message = err;
-    diagnostic.source = source;
-    diags_.add(std::move(diagnostic));
   }
   return Failure::kErrored;
 }

src/transform/bound_array_accessors.cc

@@ -102,11 +102,7 @@ ast::ArrayAccessorExpression* BoundArrayAccessors::Transform(
       auto* limit = b.Sub(arr_len, b.Expr(1u));
       new_idx = b.Call("min", b.Construct<u32>(ctx->Clone(old_idx)), limit);
     } else {
-      diag::Diagnostic err;
+      diags->add_error("invalid 0 size", expr->source());
-      err.severity = diag::Severity::Error;
-      err.message = "invalid 0 size";
-      err.source = expr->source();
-      diags->add(std::move(err));
       return nullptr;
     }
   } else if (auto* c = old_idx->As<ast::ScalarConstructorExpression>()) {
@@ -118,11 +114,8 @@ ast::ArrayAccessorExpression* BoundArrayAccessors::Transform(
     } else if (auto* uint = lit->As<ast::UintLiteral>()) {
       new_idx = b.Expr(std::min(uint->value(), size - 1));
     } else {
-      diag::Diagnostic err;
+      diags->add_error("unknown scalar constructor type for accessor",
-      err.severity = diag::Severity::Error;
+                       expr->source());
-      err.message = "unknown scalar constructor type for accessor";
-      err.source = expr->source();
-      diags->add(std::move(err));
       return nullptr;
     }
   } else {

src/transform/first_index_offset.cc

@@ -88,11 +88,9 @@ Transform::Output FirstIndexOffset::Run(const Program* in) {
   for (ast::Variable* var : in->AST().GlobalVariables()) {
     if (auto* dec_var = var->As<ast::Variable>()) {
       if (dec_var->symbol() == in->Symbols().Get(kBufferName)) {
-        diag::Diagnostic err;
-        err.message = "First index offset transform has already been applied.";
-        err.severity = diag::Severity::Error;
         Output out;
-        out.diagnostics.add(std::move(err));
+        out.diagnostics.add_error(
+            "First index offset transform has already been applied.");
         return out;
       }
     }
@@ -106,11 +104,8 @@ Transform::Output FirstIndexOffset::Run(const Program* in) {
     ProgramBuilder builder = in->CloneAsBuilder();
     TypeDeterminer td(&builder);
     if (!td.Determine()) {
-      diag::Diagnostic err;
-      err.severity = diag::Severity::Error;
-      err.message = td.error();
       Output out;
-      out.diagnostics.add(std::move(err));
+      out.diagnostics.add_error(td.error());
       return out;
     }
     program = Program(std::move(builder));

src/transform/vertex_pulling.cc

@@ -78,11 +78,8 @@ void VertexPulling::SetPullingBufferBindingSet(uint32_t number) {
 Transform::Output VertexPulling::Run(const Program* in) {
   // Check SetVertexState was called
   if (!cfg.vertex_state_set) {
-    diag::Diagnostic err;
-    err.severity = diag::Severity::Error;
-    err.message = "SetVertexState not called";
     Output out;
-    out.diagnostics.add(std::move(err));
+    out.diagnostics.add_error("SetVertexState not called");
     return out;
   }
 
@@ -90,11 +87,8 @@ Transform::Output VertexPulling::Run(const Program* in) {
   auto* func = in->AST().Functions().Find(
       in->Symbols().Get(cfg.entry_point_name), ast::PipelineStage::kVertex);
   if (func == nullptr) {
-    diag::Diagnostic err;
-    err.severity = diag::Severity::Error;
-    err.message = "Vertex stage entry point not found";
     Output out;
-    out.diagnostics.add(std::move(err));
+    out.diagnostics.add_error("Vertex stage entry point not found");
     return out;
   }
 

src/type_determiner.cc

@@ -69,10 +69,9 @@ diag::List TypeDeterminer::Run(Program* program) {
   ProgramBuilder builder = program->CloneAsBuilder();
   TypeDeterminer td(&builder);
   if (!td.Determine()) {
-    diag::Diagnostic err;
+    diag::List diagnostics;
-    err.severity = diag::Severity::Error;
+    diagnostics.add_error(td.error());
-    err.message = td.error();
+    return diagnostics;
-    return {err};
   }
   *program = Program(std::move(builder));
   return {};

src/validator/validator_impl.cc

@@ -58,11 +58,7 @@ void ValidatorImpl::add_error(const Source& src,
 }
 
 void ValidatorImpl::add_error(const Source& src, const std::string& msg) {
-  diag::Diagnostic diag;
+  diags_.add_error(msg, src);
-  diag.severity = diag::Severity::Error;
-  diag.source = src;
-  diag.message = msg;
-  diags_.add(std::move(diag));
 }
 
 bool ValidatorImpl::Validate() {