Fix sort uniform bug

Current sort doesn't take care of the case when both uniforms
are struct specfiers. Given that struct types are easily broken by
sort, make the sort not reordering uniforms if both are structs.

Bug: b/437825940
Change-Id: Idda1810ac4234f7e1547735e4e09658ab0a57eed
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6842936
Reviewed-by: Charlie Lao <[email protected]>
Reviewed-by: Amirali Abdolrashidi <[email protected]>
Reviewed-by: Shahbaz Youssefi <[email protected]>

Author: HuYuxin

src/compiler/translator/Compiler.cpp

@@ -236,12 +236,16 @@ struct UniformSortComparator
                                       ->getAsSymbolNode()
                                       ->variable()
                                       .getType();
+        // If both uniforms are structs, do not reorder them
+        if (firstType.getStruct() != nullptr && secondType.getStruct() != nullptr)
+        {
+            return false;
+        }
         // First, sort by precision: lowp and mediump are smaller than highp
         if (firstType.getPrecision() != secondType.getPrecision())
         {
             return firstType.getPrecision() != TPrecision::EbpHigh;
         }
-
         // We don't sort highp uniforms. If both uniforms are highp, consider them as equivalent
         if (firstType.getPrecision() == TPrecision::EbpHigh &&
             secondType.getPrecision() == TPrecision::EbpHigh)
@@ -256,11 +260,6 @@ struct UniformSortComparator
         {
             return firstType.getStruct() == nullptr;
         }
-        // If both are struct, place the one that has specifier in the front
-        if (firstType.getStruct() != nullptr && secondType.getStruct() != nullptr)
-        {
-            return firstType.isStructSpecifier();
-        }
         // criteria 2: sort by arrayness. Non-array element is smaller.
         if (firstType.isArray() != secondType.isArray())
         {

src/tests/gl_tests/UniformTest.cpp

@@ -2485,6 +2485,22 @@ TEST_P(UniformTestES31, UniformReorderDoesNotBreakStructUniforms)
     ASSERT_NE(program, 0u);
 }
 
+// That that TCompiler::sortUniforms() does not break the shader code when there are multiple
+// uniforms of the struct data type, and both of them are struct specifiers, and one struct
+// references the other struct.
+TEST_P(UniformTestES31, UniformReorderDoesNotBreakStructUniformsV2)
+{
+    constexpr char kFS[] =
+        "#version 310 es\n"
+        "precision mediump float;\n"
+        "uniform struct S1 { samplerCube ar; } a1;\n"
+        "uniform struct S2 { S1 s; } a2;\n"
+        "void main (void)\n"
+        "{}";
+    GLuint program = CompileProgram(essl31_shaders::vs::Simple(), kFS);
+    ASSERT_NE(program, 0u);
+}
+
 // Test a uniform struct containing a non-square matrix and a boolean.
 // Minimal test case for a bug revealed by dEQP tests.
 TEST_P(UniformTestES3, StructWithNonSquareMatrixAndBool)