fix(shader): decorate rect-list gl_Position as Invariant

The vertex stage already marks Position Invariant, and the rect-list stages have to match that interface.

core/libs/prx/libSceAgcDriver/CMakeLists.txt

@@ -619,6 +619,19 @@ target_link_libraries(agc_formatted_buffer_once_tests PRIVATE shader_recompiler_
 set_target_properties(agc_formatted_buffer_once_tests PROPERTIES CXX_EXTENSIONS OFF)
 configure_windows_unwind(agc_formatted_buffer_once_tests)
 
+add_test_executable(agc_rect_list_position_invariant_tests EXCLUDE_FROM_ALL tests/RectListPositionInvariant.cpp)
+target_link_libraries(agc_rect_list_position_invariant_tests PRIVATE shader_recompiler_agc_driver libc)
+set_target_properties(agc_rect_list_position_invariant_tests PROPERTIES CXX_EXTENSIONS OFF)
+configure_windows_unwind(agc_rect_list_position_invariant_tests)
+if(BUILD_TESTING)
+    set_target_properties(agc_rect_list_position_invariant_tests PROPERTIES EXCLUDE_FROM_ALL OFF)
+    add_test(NAME agc_rect_list_position_invariant COMMAND agc_rect_list_position_invariant_tests)
+    if(WIN32)
+        set_tests_properties(agc_rect_list_position_invariant PROPERTIES ENVIRONMENT_MODIFICATION
+            "PATH=path_list_prepend:$<TARGET_FILE_DIR:libc>")
+    endif()
+endif()
+
 add_test_executable(agc_shader_disk_cache_tests EXCLUDE_FROM_ALL tests/ShaderDiskCache.cpp)
 target_include_directories(agc_shader_disk_cache_tests PRIVATE ${LIBS_INCLUDE_DIR})
 target_link_libraries(agc_shader_disk_cache_tests PRIVATE shader_recompiler_agc_driver libc)

core/libs/prx/libSceAgcDriver/tests/RectListPositionInvariant.cpp

@@ -0,0 +1,66 @@
+#include "Recompiler.hpp"
+#include <algorithm>
+#include <array>
+#include <cstdint>
+#include <cstdio>
+#include <exception>
+#include <span>
+#include <spirv/unified1/spirv.hpp>
+#include <stdexcept>
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace {
+
+using namespace ShaderRecompiler;
+
+void Check(bool condition, const std::string& message) {
+    if (!condition) throw std::runtime_error(message);
+}
+
+bool PositionIsInvariant(std::span<const std::uint32_t> words) {
+    Check(words.size() >= 5 && words[0] == spv::MagicNumber, "rect-list invariant: missing SPIR-V module");
+    std::vector<std::pair<std::uint32_t, std::uint32_t>> positionMembers;
+    std::vector<std::pair<std::uint32_t, std::uint32_t>> invariantMembers;
+    for (std::size_t offset = 5; offset < words.size();) {
+        const auto count = words[offset] >> spv::WordCountShift;
+        Check(count != 0 && count <= words.size() - offset, "rect-list invariant: malformed SPIR-V instruction");
+        const auto opcode = words[offset] & spv::OpCodeMask;
+        if (opcode == spv::OpMemberDecorate && count == 5 && words[offset + 3] == spv::DecorationBuiltIn && words[offset + 4] == spv::BuiltInPosition) {
+            positionMembers.emplace_back(words[offset + 1], words[offset + 2]);
+        }
+        if (opcode == spv::OpMemberDecorate && count == 4 && words[offset + 3] == spv::DecorationInvariant) {
+            invariantMembers.emplace_back(words[offset + 1], words[offset + 2]);
+        }
+        offset += count;
+    }
+    Check(!positionMembers.empty(), "rect-list invariant: shader has no gl_Position");
+    for (const auto& member : positionMembers) {
+        if (std::find(invariantMembers.begin(), invariantMembers.end(), member) == invariantMembers.end()) return false;
+    }
+    return true;
+}
+
+}
+
+int main() {
+    try {
+        static constexpr std::array<std::uint32_t, 2> capabilities{spv::CapabilityShader, spv::CapabilityTessellation};
+        SpirvTarget target{};
+        target.vulkanVersion = 0x00401000u;
+        target.spirvVersion = 0x00010400u;
+        target.supportedCapabilities = capabilities;
+        target.tessellation = TessellationTargetLimits{32, 128, 128, 120, 4096, 128, 128};
+        RecompileResult vertex;
+        RecompileResult fragment;
+        const auto shaders = BuildRectListShaders(vertex, fragment, target);
+        Check(PositionIsInvariant(shaders.control.spirv.Words()), "rect-list control gl_Position is not Invariant");
+        Check(PositionIsInvariant(shaders.evaluation.spirv.Words()), "rect-list evaluation gl_Position is not Invariant");
+        std::printf("rect-list position invariant tests passed\n");
+        return 0;
+    } catch (const std::exception& error) {
+        std::fprintf(stderr, "%s\n", error.what());
+        return 1;
+    }
+}

core/shader/recompiler/SpirvBackend/src/RectListShaders.cpp

@@ -41,7 +41,7 @@ public:
         vec4FloatType = type(spv::OpTypeVector, floatType, 4u);
         functionType = type(spv::OpTypeFunction, voidType);
 
-        perVertexType = builder.DecoratedType(spv::OpTypeStruct, {{spv::OpMemberDecorate, {0u, spv::DecorationBuiltIn, spv::BuiltInPosition}}, {spv::OpDecorate, {spv::DecorationBlock}}}, vec4FloatType);
+        perVertexType = builder.DecoratedType(spv::OpTypeStruct, {{spv::OpMemberDecorate, {0u, spv::DecorationBuiltIn, spv::BuiltInPosition}}, {spv::OpMemberDecorate, {0u, spv::DecorationInvariant}}, {spv::OpDecorate, {spv::DecorationBlock}}}, vec4FloatType);
 
         ptrInputVec4Float = pointer(spv::StorageClassInput, vec4FloatType);
         ptrOutputVec4Float = pointer(spv::StorageClassOutput, vec4FloatType);