tint: make uniformity analysis failures warnings again

Bug: tint:1728
Change-Id: I7684a49567d2e5c2c49f3c5b1d45a9fe543abbc9
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/106940
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>

docs/tint/origin-trial-changes.md

@@ -1,5 +1,11 @@
 # Tint changes during Origin Trial
 
+## Changes for M109
+
+### New features
+
+* Uniformity analysis failures are warnings again [tint:1728](crbug.com/tint/1728)
+
 ## Changes for M108
 
 ### New features

src/dawn/tests/end2end/ShaderTests.cpp

@@ -872,7 +872,8 @@ TEST_P(ShaderTests, ConflictingBindingsDueToTransformOrder) {
 
 // Check that chromium_disable_uniformity_analysis can be used. It is normally disallowed as unsafe
 // but DawnTests allow all unsafe APIs by default.
-TEST_P(ShaderTests, CheckUsageOf_chromium_disable_uniformity_analysis) {
+// TODO(crbug.com/tint/1728): Enable again when uniformity failures are errors again
+TEST_P(ShaderTests, DISABLED_CheckUsageOf_chromium_disable_uniformity_analysis) {
     wgpu::ShaderModule module = utils::CreateShaderModule(device, R"(
         enable chromium_disable_uniformity_analysis;
 

src/tint/resolver/resolver.cc

@@ -174,7 +174,9 @@ bool Resolver::ResolveInternal() {
 
     if (!enabled_extensions_.Contains(ast::Extension::kChromiumDisableUniformityAnalysis)) {
         if (!AnalyzeUniformity(builder_, dependencies_)) {
-            return false;
+            if (kUniformityFailuresAsError) {
+                return false;
+            }
         }
     }
 

src/tint/resolver/uniformity.cc

@@ -1672,7 +1672,9 @@ class UniformityGraph {
         // the `MakeError` function.
         auto report = [&](Source source, std::string msg) {
             diag::Diagnostic error{};
-            error.severity = note ? diag::Severity::Note : diag::Severity::Error;
+            auto failureSeverity =
+                kUniformityFailuresAsError ? diag::Severity::Error : diag::Severity::Warning;
+            error.severity = note ? diag::Severity::Note : failureSeverity;
             error.system = diag::System::Resolver;
             error.source = source;
             error.message = msg;

src/tint/resolver/uniformity.h

@@ -25,6 +25,9 @@ class ProgramBuilder;
 
 namespace tint::resolver {
 
+/// If true, uniformity analysis failures will be treated as an error, else as a warning.
+constexpr bool kUniformityFailuresAsError = false;
+
 /// Analyze the uniformity of a program.
 /// @param builder the program to analyze
 /// @param dependency_graph the dependency-ordered module-scope declarations