Allow attributes and uniforms to have the same name

src/libANGLE/ProgramLinkedResources.cpp

@@ -1572,9 +1572,18 @@ bool LinkValidateProgramGlobalNames(InfoLog &infoLog, const HasAttachedShaders &
     Shader *vertexShader = programOrPipeline.getAttachedShader(ShaderType::Vertex);
     if (vertexShader)
     {
+        // ESSL 3.00.6 section 4.3.5:
+        // If a uniform variable name is declared in one stage (e.g., a vertex shader)
+        // but not in another (e.g., a fragment shader), then that name is still
+        // available in the other stage for a different use.
+        std::unordered_set<std::string> uniforms;
+        for (const sh::ShaderVariable &uniform : vertexShader->getUniforms())
+        {
+            uniforms.insert(uniform.name);
+        }
         for (const auto &attrib : vertexShader->getActiveAttributes())
         {
-            if (uniformMap.count(attrib.name))
+            if (uniforms.count(attrib.name))
             {
                 infoLog << "Name conflicts between a uniform and an attribute: " << attrib.name;
                 return false;

src/tests/gl_tests/GLSLTest.cpp

@@ -8808,6 +8808,32 @@ void main() {
     EXPECT_NE(0u, program);
 }
 
+// Test that reusing the same uniform variable name for different uses across stages links fine.
+TEST_P(GLSLTest_ES31, UniformVariableNameReuseAcrossStages)
+{
+    constexpr char kVS[] = R"(#version 310 es
+precision mediump float;
+in highp vec4 variableWithSameName;
+
+void main() {
+    gl_Position = variableWithSameName;
+}
+)";
+
+    constexpr char kFS[] = R"(#version 310 es
+precision mediump float;
+uniform vec4 variableWithSameName;
+out vec4 col;
+
+void main() {
+    col = vec4(variableWithSameName);
+}
+)";
+
+    GLuint program = CompileProgram(kVS, kFS);
+    EXPECT_NE(0u, program);
+}
+
 // Verify that precision match validation of uniforms is performed only if they are statically used
 TEST_P(GLSLTest_ES31, UniformPrecisionMatchValidation)
 {

src/tests/gl_tests/WebGLCompatibilityTest.cpp

@@ -2968,7 +2968,7 @@ void main()
 })";
 
     GLuint program = CompileProgram(kVS, kFS);
-    EXPECT_EQ(0u, program);
+    EXPECT_NE(0u, program);
 }
 
 // Test dimension and image size validation of compressed textures