shader_recompiler: Use functions for indirect const buffer accesses

src/shader_recompiler/backend/spirv/emit_spirv_context_get_set.cpp

@@ -123,7 +123,7 @@ std::optional<OutAttr> OutputAttrPointer(EmitContext& ctx, IR::Attribute attr) {
 }
 
 Id GetCbuf(EmitContext& ctx, Id result_type, Id UniformDefinitions::*member_ptr, u32 element_size,
-           const IR::Value& binding, const IR::Value& offset) {
+           const IR::Value& binding, const IR::Value& offset, const Id indirect_func) {
     Id buffer_offset;
 
     const Id uniform_type{ctx.uniform_types.*member_ptr};
@@ -145,42 +145,19 @@ Id GetCbuf(EmitContext& ctx, Id result_type, Id UniformDefinitions::*member_ptr,
             ctx.OpAccessChain(uniform_type, cbuf, ctx.u32_zero_value, buffer_offset)};
         return ctx.OpLoad(result_type, access_chain);
     } else {
-        const Id index{ctx.Def(binding)};
+        const std::array<Id, 2> arguments{ctx.Def(binding), buffer_offset};
-        const Id merge_label = ctx.OpLabel();
+        return ctx.OpFunctionCall(result_type, indirect_func, arguments);
-
-        std::array<Id, Info::MAX_CBUFS> buf_labels;
-        std::array<Sirit::Literal, Info::MAX_CBUFS> buf_literals;
-        for (u32 i = 0; i < Info::MAX_CBUFS; i++) {
-            buf_labels[i] = ctx.OpLabel();
-            buf_literals[i] = Sirit::Literal{i};
-        }
-
-        ctx.OpSelectionMerge(merge_label, spv::SelectionControlMask::MaskNone);
-        ctx.OpSwitch(index, buf_labels[0], buf_literals, buf_labels);
-
-        std::array<Id, Info::MAX_CBUFS * 2> phi_targets;
-        for (u32 i = 0; i < Info::MAX_CBUFS; i++) {
-            ctx.AddLabel(buf_labels[i]);
-            const Id cbuf{ctx.cbufs[i].*member_ptr};
-            const Id access_chain{
-                ctx.OpAccessChain(uniform_type, cbuf, ctx.u32_zero_value, buffer_offset)};
-            phi_targets[2 * i + 0] = ctx.OpLoad(result_type, access_chain);
-            phi_targets[2 * i + 1] = buf_labels[i];
-            ctx.OpBranch(merge_label);
-        }
-
-        ctx.AddLabel(merge_label);
-
-        return ctx.OpPhi(result_type, phi_targets);
     }
 }
 
 Id GetCbufU32(EmitContext& ctx, const IR::Value& binding, const IR::Value& offset) {
-    return GetCbuf(ctx, ctx.U32[1], &UniformDefinitions::U32, sizeof(u32), binding, offset);
+    return GetCbuf(ctx, ctx.U32[1], &UniformDefinitions::U32, sizeof(u32), binding, offset,
+                   ctx.load_const_func_u32);
 }
 
 Id GetCbufU32x4(EmitContext& ctx, const IR::Value& binding, const IR::Value& offset) {
-    return GetCbuf(ctx, ctx.U32[4], &UniformDefinitions::U32x4, sizeof(u32[4]), binding, offset);
+    return GetCbuf(ctx, ctx.U32[4], &UniformDefinitions::U32x4, sizeof(u32[4]), binding, offset,
+                   ctx.load_const_func_u32x4);
 }
 
 Id GetCbufElement(EmitContext& ctx, Id vector, const IR::Value& offset, u32 index_offset) {
@@ -231,7 +208,8 @@ void EmitGetIndirectBranchVariable(EmitContext&) {
 
 Id EmitGetCbufU8(EmitContext& ctx, const IR::Value& binding, const IR::Value& offset) {
     if (ctx.profile.support_descriptor_aliasing && ctx.profile.support_int8) {
-        const Id load{GetCbuf(ctx, ctx.U8, &UniformDefinitions::U8, sizeof(u8), binding, offset)};
+        const Id load{GetCbuf(ctx, ctx.U8, &UniformDefinitions::U8, sizeof(u8), binding, offset,
+                              ctx.load_const_func_u8)};
         return ctx.OpUConvert(ctx.U32[1], load);
     }
     Id element{};
@@ -247,7 +225,8 @@ Id EmitGetCbufU8(EmitContext& ctx, const IR::Value& binding, const IR::Value& of
 
 Id EmitGetCbufS8(EmitContext& ctx, const IR::Value& binding, const IR::Value& offset) {
     if (ctx.profile.support_descriptor_aliasing && ctx.profile.support_int8) {
-        const Id load{GetCbuf(ctx, ctx.S8, &UniformDefinitions::S8, sizeof(s8), binding, offset)};
+        const Id load{GetCbuf(ctx, ctx.S8, &UniformDefinitions::S8, sizeof(s8), binding, offset,
+                              ctx.load_const_func_u8)};
         return ctx.OpSConvert(ctx.U32[1], load);
     }
     Id element{};
@@ -263,8 +242,8 @@ Id EmitGetCbufS8(EmitContext& ctx, const IR::Value& binding, const IR::Value& of
 
 Id EmitGetCbufU16(EmitContext& ctx, const IR::Value& binding, const IR::Value& offset) {
     if (ctx.profile.support_descriptor_aliasing && ctx.profile.support_int16) {
-        const Id load{
+        const Id load{GetCbuf(ctx, ctx.U16, &UniformDefinitions::U16, sizeof(u16), binding, offset,
-            GetCbuf(ctx, ctx.U16, &UniformDefinitions::U16, sizeof(u16), binding, offset)};
+                              ctx.load_const_func_u16)};
         return ctx.OpUConvert(ctx.U32[1], load);
     }
     Id element{};
@@ -280,8 +259,8 @@ Id EmitGetCbufU16(EmitContext& ctx, const IR::Value& binding, const IR::Value& o
 
 Id EmitGetCbufS16(EmitContext& ctx, const IR::Value& binding, const IR::Value& offset) {
     if (ctx.profile.support_descriptor_aliasing && ctx.profile.support_int16) {
-        const Id load{
+        const Id load{GetCbuf(ctx, ctx.S16, &UniformDefinitions::S16, sizeof(s16), binding, offset,
-            GetCbuf(ctx, ctx.S16, &UniformDefinitions::S16, sizeof(s16), binding, offset)};
+                              ctx.load_const_func_u16)};
         return ctx.OpSConvert(ctx.U32[1], load);
     }
     Id element{};
@@ -306,7 +285,8 @@ Id EmitGetCbufU32(EmitContext& ctx, const IR::Value& binding, const IR::Value& o
 
 Id EmitGetCbufF32(EmitContext& ctx, const IR::Value& binding, const IR::Value& offset) {
     if (ctx.profile.support_descriptor_aliasing) {
-        return GetCbuf(ctx, ctx.F32[1], &UniformDefinitions::F32, sizeof(f32), binding, offset);
+        return GetCbuf(ctx, ctx.F32[1], &UniformDefinitions::F32, sizeof(f32), binding, offset,
+                       ctx.load_const_func_f32);
     } else {
         const Id vector{GetCbufU32x4(ctx, binding, offset)};
         return ctx.OpBitcast(ctx.F32[1], GetCbufElement(ctx, vector, offset, 0u));
@@ -315,8 +295,8 @@ Id EmitGetCbufF32(EmitContext& ctx, const IR::Value& binding, const IR::Value& o
 
 Id EmitGetCbufU32x2(EmitContext& ctx, const IR::Value& binding, const IR::Value& offset) {
     if (ctx.profile.support_descriptor_aliasing) {
-        return GetCbuf(ctx, ctx.U32[2], &UniformDefinitions::U32x2, sizeof(u32[2]), binding,
+        return GetCbuf(ctx, ctx.U32[2], &UniformDefinitions::U32x2, sizeof(u32[2]), binding, offset,
-                       offset);
+                       ctx.load_const_func_u32x2);
     } else {
         const Id vector{GetCbufU32x4(ctx, binding, offset)};
         return ctx.OpCompositeConstruct(ctx.U32[2], GetCbufElement(ctx, vector, offset, 0u),

src/shader_recompiler/backend/spirv/spirv_emit_context.cpp

@@ -464,6 +464,7 @@ EmitContext::EmitContext(const Profile& profile_, const RuntimeInfo& runtime_inf
     DefineSharedMemory(program);
     DefineSharedMemoryFunctions(program);
     DefineConstantBuffers(program.info, uniform_binding);
+    DefineConstantBufferIndirectFunctions(program.info);
     DefineStorageBuffers(program.info, storage_binding);
     DefineTextureBuffers(program.info, texture_binding);
     DefineImageBuffers(program.info, image_binding);
@@ -1027,6 +1028,69 @@ void EmitContext::DefineConstantBuffers(const Info& info, u32& binding) {
     binding += static_cast<u32>(info.constant_buffer_descriptors.size());
 }
 
+void EmitContext::DefineConstantBufferIndirectFunctions(const Info& info) {
+    if (!info.uses_cbuf_indirect) {
+        return;
+    }
+
+    const auto make_accessor{[&](Id buffer_type, Id UniformDefinitions::*member_ptr) {
+        const Id func_type{TypeFunction(buffer_type, U32[1], U32[1])};
+        const Id func{OpFunction(buffer_type, spv::FunctionControlMask::MaskNone, func_type)};
+        const Id binding{OpFunctionParameter(U32[1])};
+        const Id offset{OpFunctionParameter(U32[1])};
+
+        AddLabel();
+
+        const Id merge_label{OpLabel()};
+        const Id uniform_type{uniform_types.*member_ptr};
+
+        std::array<Id, Info::MAX_CBUFS> buf_labels;
+        std::array<Sirit::Literal, Info::MAX_CBUFS> buf_literals;
+        for (u32 i = 0; i < Info::MAX_CBUFS; i++) {
+            buf_labels[i] = OpLabel();
+            buf_literals[i] = Sirit::Literal{i};
+        }
+
+        OpSelectionMerge(merge_label, spv::SelectionControlMask::MaskNone);
+        OpSwitch(binding, buf_labels[0], buf_literals, buf_labels);
+
+        for (u32 i = 0; i < Info::MAX_CBUFS; i++) {
+            AddLabel(buf_labels[i]);
+            const Id cbuf{cbufs[i].*member_ptr};
+            const Id access_chain{OpAccessChain(uniform_type, cbuf, u32_zero_value, offset)};
+            const Id result{OpLoad(buffer_type, access_chain)};
+            OpReturnValue(result);
+        }
+
+        AddLabel(merge_label);
+        OpUnreachable();
+        OpFunctionEnd();
+
+        return func;
+    }};
+
+    IR::Type types{info.used_constant_buffer_types};
+
+    if (True(types & IR::Type::U8)) {
+        load_const_func_u8 = make_accessor(U8, &UniformDefinitions::U8);
+    }
+    if (True(types & IR::Type::U16)) {
+        load_const_func_u16 = make_accessor(U16, &UniformDefinitions::U16);
+    }
+    if (True(types & IR::Type::F32)) {
+        load_const_func_f32 = make_accessor(F32[1], &UniformDefinitions::F32);
+    }
+    if (True(types & IR::Type::U32)) {
+        load_const_func_u32 = make_accessor(U32[1], &UniformDefinitions::U32);
+    }
+    if (True(types & IR::Type::U32x2)) {
+        load_const_func_u32x2 = make_accessor(U32[2], &UniformDefinitions::U32x2);
+    }
+    if (True(types & IR::Type::U32x4)) {
+        load_const_func_u32x4 = make_accessor(U32[4], &UniformDefinitions::U32x4);
+    }
+}
+
 void EmitContext::DefineStorageBuffers(const Info& info, u32& binding) {
     if (info.storage_buffers_descriptors.empty()) {
         return;

src/shader_recompiler/backend/spirv/spirv_emit_context.h

@@ -294,6 +294,13 @@ public:
 
     std::vector<Id> interfaces;
 
+    Id load_const_func_u8{};
+    Id load_const_func_u16{};
+    Id load_const_func_u32{};
+    Id load_const_func_f32{};
+    Id load_const_func_u32x2{};
+    Id load_const_func_u32x4{};
+
 private:
     void DefineCommonTypes(const Info& info);
     void DefineCommonConstants();
@@ -302,6 +309,7 @@ private:
     void DefineSharedMemory(const IR::Program& program);
     void DefineSharedMemoryFunctions(const IR::Program& program);
     void DefineConstantBuffers(const Info& info, u32& binding);
+    void DefineConstantBufferIndirectFunctions(const Info& info);
     void DefineStorageBuffers(const Info& info, u32& binding);
     void DefineTextureBuffers(const Info& info, u32& binding);
     void DefineImageBuffers(const Info& info, u32& binding);

src/shader_recompiler/ir_opt/collect_shader_info_pass.cpp

@@ -30,6 +30,8 @@ void AddConstantBufferDescriptor(Info& info, u32 index, u32 count) {
 }
 
 void AddRegisterIndexedLdc(Info& info) {
+    info.uses_cbuf_indirect = true;
+
     // The shader can use any possible constant buffer
     info.constant_buffer_mask = (1 << Info::MAX_CBUFS) - 1;
 

src/shader_recompiler/shader_info.h

@@ -173,6 +173,7 @@ struct Info {
     bool uses_atomic_image_u32{};
     bool uses_shadow_lod{};
     bool uses_rescaling_uniform{};
+    bool uses_cbuf_indirect{};
 
     IR::Type used_constant_buffer_types{};
     IR::Type used_storage_buffer_types{};