Vertex Loader C++11 Support

KhronosGroup · Oct 2, 2023 · 2606371 · 2606371
1 parent c3bf805
commit 2606371
Show file tree

Hide file tree

Showing 4 changed files with 90 additions and 7 deletions.
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -288,7 +288,6 @@ if (SPIRV_CROSS_STATIC)
 	if (SPIRV_CROSS_ENABLE_MSL)
 		spirv_cross_add_library(spirv-cross-msl spirv_cross_msl STATIC
 				${spirv-cross-msl-sources})
-		target_compile_features(spirv-cross-msl PRIVATE cxx_std_14)
 		if (SPIRV_CROSS_ENABLE_GLSL)
 			target_link_libraries(spirv-cross-msl PRIVATE spirv-cross-glsl)
 		else()
@@ -377,7 +376,6 @@ if (SPIRV_CROSS_SHARED)
 	if (SPIRV_CROSS_ENABLE_MSL)
 		if (SPIRV_CROSS_ENABLE_GLSL)
 			target_sources(spirv-cross-c-shared PRIVATE ${spirv-cross-msl-sources})
-			target_compile_features(spirv-cross-c-shared PRIVATE cxx_std_14)
 		else()
 			message(FATAL_ERROR "Must enable GLSL support to enable MSL support.")
 		endif()

diff --git a/Makefile b/Makefile
@@ -13,7 +13,7 @@ STATIC_LIB := lib$(TARGET).a
 
 DEPS := $(OBJECTS:.o=.d) $(CLI_OBJECTS:.o=.d)
 
-CXXFLAGS += -std=c++14 -Wall -Wextra -Wshadow -Wno-deprecated-declarations
+CXXFLAGS += -std=c++11 -Wall -Wextra -Wshadow -Wno-deprecated-declarations
 
 ifeq ($(DEBUG), 1)
 	CXXFLAGS += -O0 -g

diff --git a/spirv_msl.cpp b/spirv_msl.cpp
@@ -7579,7 +7579,7 @@ void CompilerMSL::prepare_shader_vertex_loader()
 	}
 
 	auto &entry_func = get<SPIRFunction>(ir.default_entry_point);
-	entry_func.add_fixup_hook_in([this, load = std::move(load)]{
+	entry_func.add_fixup_hook_in([this, load]{
 		statement(get_name(this->get<SPIRVariable>(stage_in_var_id).basetype), " ", get_name(stage_in_var_id), " = spvLoadVertex(", load, ");");
 	}, SPIRFunction::FixupInPriority::VertexLoad);
 }

diff --git a/spirv_msl_vertex_loader.cpp b/spirv_msl_vertex_loader.cpp
@@ -33,8 +33,17 @@ struct ConstexprLookupTable
 	static constexpr std::size_t size() { return Size; }
 };
 
+template <typename First, typename Second>
+struct ConstexprPair
+{
+	First first;
+	Second second;
+};
+
+#if __cplusplus >= 201300L
 template <uint32_t Highest, typename OutType, uint32_t InSize, typename IndexType>
-constexpr static ConstexprLookupTable<OutType, Highest + 1> gen_lookup_table(const std::pair<IndexType, OutType> (&entry_list)[InSize])
+constexpr static ConstexprLookupTable<OutType, Highest + 1> gen_lookup_table(
+    const ConstexprPair<IndexType, OutType> (&entry_list)[InSize])
 {
 #define CXPR_ASSERT_REL(x) ((x) ? static_cast<void>(0) : abort())
 	bool written[Highest + 1] = {};
@@ -50,6 +59,82 @@ constexpr static ConstexprLookupTable<OutType, Highest + 1> gen_lookup_table(con
 #undef CXPR_ASSERT_REL
 	return output;
 }
+#else
+namespace detail
+{
+
+// From https://stackoverflow.com/a/61447603
+template<class T, T... Ints>
+struct integer_sequence {};
+
+template<std::size_t... Ints>
+using index_sequence = integer_sequence<std::size_t, Ints...>;
+
+template<typename Firsts, typename Last>
+struct index_sequence_eights_append;
+
+template<std::size_t... N, std::size_t... M>
+struct index_sequence_eights_append<index_sequence<N...>, index_sequence<M...>> {
+	using type = index_sequence<
+		N..., (sizeof...(N) + N)..., (2u * sizeof...(N) + N)..., (3u * sizeof...(N) + N)...,
+		(4u * sizeof...(N) + N)..., (5u * sizeof...(N) + N)..., (6u * sizeof...(N) + N)...,
+		(7u * sizeof...(N) + M)...
+	>;
+};
+
+template<std::size_t N>
+struct make_index_sequence_helper {
+	using type = typename index_sequence_eights_append<typename make_index_sequence_helper<N / 8u>::type, typename make_index_sequence_helper<N - 7u * (N / 8u)>::type>::type;
+};
+
+template<> struct make_index_sequence_helper<0> { using type = index_sequence<>; };
+template<> struct make_index_sequence_helper<1> { using type = index_sequence<0>; };
+template<> struct make_index_sequence_helper<2> { using type = index_sequence<0, 1>; };
+template<> struct make_index_sequence_helper<3> { using type = index_sequence<0, 1, 2>; };
+template<> struct make_index_sequence_helper<4> { using type = index_sequence<0, 1, 2, 3>; };
+template<> struct make_index_sequence_helper<5> { using type = index_sequence<0, 1, 2, 3, 4>; };
+template<> struct make_index_sequence_helper<6> { using type = index_sequence<0, 1, 2, 3, 4, 5>; };
+template<> struct make_index_sequence_helper<7> { using type = index_sequence<0, 1, 2, 3, 4, 5, 6>; };
+
+template<std::size_t N>
+using make_index_sequence = typename make_index_sequence_helper<N>::type;
+
+template <typename OutType, uint32_t InSize, typename IndexType, uint32_t Idx>
+struct get_matching_element
+{
+	static constexpr OutType search(const ConstexprPair<IndexType, OutType> (&entry_list)[InSize], IndexType needle)
+	{
+		return entry_list[Idx].first == needle ?
+		           entry_list[Idx].second :
+		           get_matching_element<OutType, InSize, IndexType, Idx + 1>::search(entry_list, needle);
+	}
+};
+
+template <typename OutType, uint32_t InSize, typename IndexType>
+struct get_matching_element<OutType, InSize, IndexType, InSize>
+{
+	static constexpr OutType search(const ConstexprPair<IndexType, OutType> (&)[InSize], IndexType)
+	{
+		return {};
+	}
+};
+
+template <typename OutType, uint32_t InSize, typename IndexType, std::size_t... I>
+constexpr static ConstexprLookupTable<OutType, sizeof...(I)> gen_lookup_table(
+    const ConstexprPair<IndexType, OutType> (&entry_list)[InSize], index_sequence<I...>)
+{
+	return { get_matching_element<OutType, InSize, IndexType, 0>::search(entry_list, static_cast<IndexType>(I))... };
+}
+
+} // namespace detail
+
+template <uint32_t Highest, typename OutType, uint32_t InSize, typename IndexType>
+constexpr static ConstexprLookupTable<OutType, Highest + 1> gen_lookup_table(
+    const ConstexprPair<IndexType, OutType> (&entry_list)[InSize])
+{
+	return detail::gen_lookup_table(entry_list, detail::make_index_sequence<Highest + 1>{});
+}
+#endif
 
 const MSLFormatInfo &CompilerMSL::get_format_info(MSLFormat format)
 {
@@ -86,7 +171,7 @@ const MSLFormatInfo &CompilerMSL::get_format_info(MSLFormat format)
 #define SIMPLE_FORMAT_VK_PACKED(log2_align, elems, type, order) FORMAT(log2_align, elems, EvenAHigh, type, false, order, true)
 #define SIMPLE_FORMAT(log2_align, elems, type, order) FORMAT(log2_align, elems, EvenAHigh, type, false, order, false)
 #define PACKED_FORMAT(log2_align, elems, packing, type, order) FORMAT(log2_align, elems, packing, type, true, order, false)
-	static constexpr std::pair<MSLFormat, MSLFormatInfo> s_vertex_info_entries[] = {
+	static constexpr ConstexprPair<MSLFormat, MSLFormatInfo> s_vertex_info_entries[] = {
 		{ MSL_FORMAT_UNDEFINED, {} },
 		// Packed Formats
 		// (VkFormat uses big endian names, which makes the bit ordering extra fun)
@@ -221,7 +306,7 @@ const MSLFormatInfo &CompilerMSL::get_format_info(MSLFormat format)
 
 	static constexpr auto s_vertex_info = gen_lookup_table<MSL_FORMAT_E5B9G9R9_UFLOAT_PACK32>(s_vertex_info_entries);
 
-	static constexpr std::pair<MSLFormat, MSLFormatInfo> s_vertex_info_high[] = {
+	static constexpr ConstexprPair<MSLFormat, MSLFormatInfo> s_vertex_info_high[] = {
 		{ MSL_FORMAT_A4R4G4B4_UNORM_PACK16,     PACKED_FORMAT(1, 4, EvenAHigh, UNorm, BGR) },
 		{ MSL_FORMAT_A4B4G4R4_UNORM_PACK16,     PACKED_FORMAT(1, 4, EvenAHigh, UNorm, RGB) },
 		{ MSL_FORMAT_A1B5G5R5_UNORM_PACK16_KHR, PACKED_FORMAT(1, 4, AlphaHigh, UNorm, RGB) },