Partial fix for inconsistencies re: #2578

Test/link.vk.inconsistentGLPerVertex.0.geom

+#version 460 core
+
+layout(lines_adjacency) in; 
+layout(triangle_strip, max_vertices = 50) out;
+
+in vs_output 
+{ 
+	vec4 color;
+} gs_in[]; 
+
+out gs_output
+{
+	vec4 color;
+} gs_out;
+
+void main()
+{
+	gl_Position = gl_in[0].gl_Position;
+	gs_out.color = gs_in[0].color;
+	EmitVertex();
+	gs_out.color = gs_in[1].color;
+	gl_Position = gl_in[1].gl_Position;
+	EmitVertex();
+	gs_out.color = gs_in[0].color;
+	gl_Position = gl_in[0].gl_Position;
+	EmitVertex();
+}

Test/link.vk.inconsistentGLPerVertex.0.vert

+#version 460 core
+
+// This test is to test isInconsistentGLPerVertexMember() workarounds.
+// Without that workaround this compile fails due to block declarations
+// in gl_PerVertex not being consistent for:
+// gl_SecondaryPositionNV
+// gl_PositionPerViewNV
+
+out vs_output 
+{ 
+	vec4 color;
+} vs_out; 
+
+in vec4 P;
+void main()
+{
+	vs_out.color = vec4(1.);
+	gl_PointSize = 1.0;
+	gl_Position = P;
+}

glslang/Include/Types.h

@@ -2336,6 +2336,17 @@ public:
         name += ';' ;
     }
 
+    // These variables are inconsistently declared inside and outside of gl_PerVertex in glslang right now.
+    // They are declared inside of 'in gl_PerVertex', but sitting as standalone when they are 'out'puts.
+    bool isInconsistentGLPerVertexMember(const TString& name) const
+    {
+        if (name == "gl_SecondaryPositionNV" ||
+            name == "gl_PositionPerViewNV")
+            return true;
+        return false;
+    }
+
+
     // Do two structure types match?  They could be declared independently,
     // in different places, but still might satisfy the definition of matching.
     // From the spec:
@@ -2351,22 +2362,48 @@ public:
             (isStruct() && right.isStruct() && structure == right.structure))
             return true;
 
-        // Both being nullptr was caught above, now they both have to be structures of the same number of elements
-        if (!isStruct() || !right.isStruct() ||
-            structure->size() != right.structure->size())
-            return false;
-
         // Structure names have to match
         if (*typeName != *right.typeName)
             return false;
 
-        // Compare the names and types of all the members, which have to match
-        for (unsigned int i = 0; i < structure->size(); ++i) {
-            if ((*structure)[i].type->getFieldName() != (*right.structure)[i].type->getFieldName())
-                return false;
+        // There are inconsistencies with how gl_PerVertex is setup. For now ignore those as errors if they
+        // are known inconsistencies.
+        bool isGLPerVertex = *typeName == "gl_PerVertex";
 
-            if (*(*structure)[i].type != *(*right.structure)[i].type)
-                return false;
+        // Both being nullptr was caught above, now they both have to be structures of the same number of elements
+        if (!isStruct() || !right.isStruct() ||
+            (structure->size() != right.structure->size() && !isGLPerVertex))
+            return false;
+
+        // Compare the names and types of all the members, which have to match
+        for (int li = 0, ri = 0; li < structure->size() || ri < right.structure->size(); ++li, ++ri) {
+            if (li < structure->size() && ri < right.structure->size()) {
+                if ((*structure)[li].type->getFieldName() == (*right.structure)[ri].type->getFieldName()) {
+                    if (*(*structure)[li].type != *(*right.structure)[ri].type)
+                        return false;
+                } else {
+                    // If one of the members is something that's inconsistently declared, skip over it
+                    // for now.
+                    if (isGLPerVertex) {
+                        if (isInconsistentGLPerVertexMember((*structure)[li].type->getFieldName())) {
+                            ri--;
+                            continue;
+                        } else if (isInconsistentGLPerVertexMember((*right.structure)[ri].type->getFieldName())) {
+                            li--;
+                            continue;
+                        }
+                    } else {
+                        return false;
+                    }
+                }
+            // If we get here, then there should only be inconsistently declared members left
+            } else if (li < structure->size()) {
+                if (!isInconsistentGLPerVertexMember((*structure)[li].type->getFieldName()))
+                    return false;
+            } else {
+                if (!isInconsistentGLPerVertexMember((*right.structure)[ri].type->getFieldName()))
+                    return false;
+            }
         }
 
         return true;

gtests/Link.FromFile.Vk.cpp

@@ -124,6 +124,7 @@ INSTANTIATE_TEST_SUITE_P(
         {"link.vk.pcNamingInvalid.0.0.vert", "link.vk.pcNamingInvalid.0.1.vert"},
         {"link.vk.multiBlocksValid.0.0.vert", "link.vk.multiBlocksValid.0.1.vert"},
         {"link.vk.multiBlocksValid.1.0.geom", "link.vk.multiBlocksValid.1.1.geom"},
+        {"link.vk.inconsistentGLPerVertex.0.vert", "link.vk.inconsistentGLPerVertex.0.geom"},
     }))
 );
 // clang-format on