From 0f56ed9759aa191568768d826a816cee66a3466c Mon Sep 17 00:00:00 2001
From: James Price <jrprice@google.com>
Date: Thu, 17 Feb 2022 20:43:19 +0000
Subject: [PATCH] tests: Validate WGSL output

WGSL was the only format that wasn't being validated for our E2E
tests, and this meant that WGSL backend bugs were sometimes going
unnoticed.

This change uses Tint's WGSL reader to validate the WGSL output.

Change-Id: I7d9e1c22feda530e7ba594725f21e576cf928647
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/80961
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
---
 samples/main.cc | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/samples/main.cc b/samples/main.cc
index 50e1f7a131..d1d0ec285a 100644
--- a/samples/main.cc
+++ b/samples/main.cc
@@ -623,7 +623,24 @@ bool GenerateWgsl(const tint::Program* program, const Options& options) {
     return false;
   }
 
-  return WriteFile(options.output_file, "w", result.wgsl);
+  if (!WriteFile(options.output_file, "w", result.wgsl)) {
+    return false;
+  }
+
+  if (options.validate) {
+    // Attempt to re-parse the output program with Tint's WGSL reader.
+    auto source = std::make_unique<tint::Source::File>(options.input_filename,
+                                                       result.wgsl);
+    auto reparsed_program = tint::reader::wgsl::Parse(source.get());
+    if (!reparsed_program.IsValid()) {
+      auto diag_printer = tint::diag::Printer::create(stderr, true);
+      tint::diag::Formatter diag_formatter;
+      diag_formatter.format(reparsed_program.Diagnostics(), diag_printer.get());
+      return false;
+    }
+  }
+
+  return true;
 #else
   (void)program;
   (void)options;