From cb215b5f215fd9db7f22f0cc9d5a516463c1da78 Mon Sep 17 00:00:00 2001
From: Tony Wasserka <neobrain@users.noreply.github.com>
Date: Thu, 19 Oct 2023 12:49:00 +0200
Subject: [PATCH] FEXLinuxTests/thunks: Add assume_compatible_data_layout tests

---
 ThunkLibs/libfex_thunk_test/api.h                |  9 +++++++++
 ThunkLibs/libfex_thunk_test/lib.cpp              |  8 ++++++++
 .../libfex_thunk_test_interface.cpp              |  4 ++++
 .../tests/thunks/thunk_testlib.64.cpp            | 16 +++++++++++++---
 4 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/ThunkLibs/libfex_thunk_test/api.h b/ThunkLibs/libfex_thunk_test/api.h
index ecdbd83bf3..daacaacecd 100644
--- a/ThunkLibs/libfex_thunk_test/api.h
+++ b/ThunkLibs/libfex_thunk_test/api.h
@@ -19,4 +19,13 @@ OpaqueType* MakeOpaqueType(uint32_t data);
 uint32_t ReadOpaqueTypeData(OpaqueType*);
 void DestroyOpaqueType(OpaqueType*);
 
+union UnionType {
+    uint32_t a;
+    int32_t b;
+    uint8_t c[4];
+};
+
+UnionType MakeUnionType(uint8_t a, uint8_t b, uint8_t c, uint8_t d);
+uint32_t GetUnionTypeA(UnionType*);
+
 }
diff --git a/ThunkLibs/libfex_thunk_test/lib.cpp b/ThunkLibs/libfex_thunk_test/lib.cpp
index 1f43381eb8..7502de1a00 100644
--- a/ThunkLibs/libfex_thunk_test/lib.cpp
+++ b/ThunkLibs/libfex_thunk_test/lib.cpp
@@ -22,4 +22,12 @@ void DestroyOpaqueType(OpaqueType* value) {
   delete value;
 }
 
+UnionType MakeUnionType(uint8_t a, uint8_t b, uint8_t c, uint8_t d) {
+  return UnionType { .c = { a, b, c, d } };
+}
+
+uint32_t GetUnionTypeA(UnionType* value) {
+  return value->a;
+}
+
 } // extern "C"
diff --git a/ThunkLibs/libfex_thunk_test/libfex_thunk_test_interface.cpp b/ThunkLibs/libfex_thunk_test/libfex_thunk_test_interface.cpp
index 7704fd0836..8e85d7d4b9 100644
--- a/ThunkLibs/libfex_thunk_test/libfex_thunk_test_interface.cpp
+++ b/ThunkLibs/libfex_thunk_test/libfex_thunk_test_interface.cpp
@@ -17,3 +17,7 @@ template<> struct fex_gen_type<OpaqueType> : fexgen::opaque_type {};
 template<> struct fex_gen_config<MakeOpaqueType> {};
 template<> struct fex_gen_config<ReadOpaqueTypeData> {};
 template<> struct fex_gen_config<DestroyOpaqueType> {};
+
+template<> struct fex_gen_type<UnionType> : fexgen::assume_compatible_data_layout {};
+template<> struct fex_gen_config<MakeUnionType> {};
+template<> struct fex_gen_config<GetUnionTypeA> {};
diff --git a/unittests/FEXLinuxTests/tests/thunks/thunk_testlib.64.cpp b/unittests/FEXLinuxTests/tests/thunks/thunk_testlib.64.cpp
index 7b49139715..7c17ad7556 100644
--- a/unittests/FEXLinuxTests/tests/thunks/thunk_testlib.64.cpp
+++ b/unittests/FEXLinuxTests/tests/thunks/thunk_testlib.64.cpp
@@ -21,6 +21,9 @@ struct Fixture {
   GET_SYMBOL(MakeOpaqueType);
   GET_SYMBOL(ReadOpaqueTypeData);
   GET_SYMBOL(DestroyOpaqueType);
+
+  GET_SYMBOL(MakeUnionType);
+  GET_SYMBOL(GetUnionTypeA);
 };
 
 TEST_CASE_METHOD(Fixture, "Trivial") {
@@ -28,7 +31,14 @@ TEST_CASE_METHOD(Fixture, "Trivial") {
 }
 
 TEST_CASE_METHOD(Fixture, "Opaque data types") {
-  auto data = MakeOpaqueType(0x1234);
-  CHECK(ReadOpaqueTypeData(data) == 0x1234);
-  DestroyOpaqueType(data);
+  {
+    auto data = MakeOpaqueType(0x1234);
+    CHECK(ReadOpaqueTypeData(data) == 0x1234);
+    DestroyOpaqueType(data);
+  }
+
+  {
+    auto data = MakeUnionType(0x1, 0x2, 0x3, 0x4);
+    CHECK(GetUnionTypeA(&data) == 0x04030201);
+  }
 }