shader: Allow tracking of indirect buffers without variable offset

While changing this code, simplify tracking code to allow returning
the base address node, this way callers don't have to manually rebuild
it on each invocation.

src/video_core/shader/decode/image.cpp

@@ -95,12 +95,8 @@ const Image& ShaderIR::GetImage(Tegra::Shader::Image image, Tegra::Shader::Image
 const Image& ShaderIR::GetBindlessImage(Tegra::Shader::Register reg,
                                         Tegra::Shader::ImageType type) {
     const Node image_register{GetRegister(reg)};
-    const Node base_image{
+    const auto [base_image, cbuf_index, cbuf_offset]{
         TrackCbuf(image_register, global_code, static_cast<s64>(global_code.size()))};
-    const auto cbuf{std::get_if<CbufNode>(&*base_image)};
-    const auto cbuf_offset_imm{std::get_if<ImmediateNode>(&*cbuf->GetOffset())};
-    const auto cbuf_offset{cbuf_offset_imm->GetValue()};
-    const auto cbuf_index{cbuf->GetIndex()};
     const auto cbuf_key{(static_cast<u64>(cbuf_index) << 32) | static_cast<u64>(cbuf_offset)};
 
     // If this image has already been used, return the existing mapping.

src/video_core/shader/decode/memory.cpp

@@ -297,18 +297,13 @@ std::tuple<Node, Node, GlobalMemoryBase> ShaderIR::TrackAndGetGlobalMemory(NodeB
     const auto addr_register{GetRegister(instr.gmem.gpr)};
     const auto immediate_offset{static_cast<u32>(instr.gmem.offset)};
 
-    const Node base_address{
-        TrackCbuf(addr_register, global_code, static_cast<s64>(global_code.size()))};
-    const auto cbuf = std::get_if<CbufNode>(&*base_address);
-    ASSERT(cbuf != nullptr);
-    const auto cbuf_offset_imm = std::get_if<ImmediateNode>(&*cbuf->GetOffset());
-    ASSERT(cbuf_offset_imm != nullptr);
-    const auto cbuf_offset = cbuf_offset_imm->GetValue();
+    const auto [base_address, index, offset] =
+        TrackCbuf(addr_register, global_code, static_cast<s64>(global_code.size()));
+    ASSERT(base_address != nullptr);
 
-    bb.push_back(
-        Comment(fmt::format("Base address is c[0x{:x}][0x{:x}]", cbuf->GetIndex(), cbuf_offset)));
+    bb.push_back(Comment(fmt::format("Base address is c[0x{:x}][0x{:x}]", index, offset)));
 
-    const GlobalMemoryBase descriptor{cbuf->GetIndex(), cbuf_offset};
+    const GlobalMemoryBase descriptor{index, offset};
     const auto& [entry, is_new] = used_global_memory.try_emplace(descriptor);
     auto& usage = entry->second;
     if (is_write) {

src/video_core/shader/decode/texture.cpp

@@ -308,13 +308,9 @@ const Sampler& ShaderIR::GetSampler(const Tegra::Shader::Sampler& sampler, Textu
 const Sampler& ShaderIR::GetBindlessSampler(const Tegra::Shader::Register& reg, TextureType type,
                                             bool is_array, bool is_shadow) {
     const Node sampler_register = GetRegister(reg);
-    const Node base_sampler =
+    const auto [base_sampler, cbuf_index, cbuf_offset] =
         TrackCbuf(sampler_register, global_code, static_cast<s64>(global_code.size()));
-    const auto cbuf = std::get_if<CbufNode>(&*base_sampler);
-    const auto cbuf_offset_imm = std::get_if<ImmediateNode>(&*cbuf->GetOffset());
-    ASSERT(cbuf_offset_imm != nullptr);
-    const auto cbuf_offset = cbuf_offset_imm->GetValue();
-    const auto cbuf_index = cbuf->GetIndex();
+    ASSERT(base_sampler != nullptr);
     const auto cbuf_key = (static_cast<u64>(cbuf_index) << 32) | static_cast<u64>(cbuf_offset);
 
     // If this sampler has already been used, return the existing mapping.

src/video_core/shader/shader_ir.cpp

@@ -61,7 +61,16 @@ Node ShaderIR::GetConstBufferIndirect(u64 index_, u64 offset_, Node node) {
     const auto [entry, is_new] = used_cbufs.try_emplace(index);
     entry->second.MarkAsUsedIndirect();
 
-    const Node final_offset = Operation(OperationCode::UAdd, NO_PRECISE, node, Immediate(offset));
+    const Node final_offset = [&]() {
+        // Attempt to inline constant buffer without a variable offset. This is done to allow
+        // tracking LDC calls.
+        if (const auto gpr = std::get_if<GprNode>(&*node)) {
+            if (gpr->GetIndex() == Register::ZeroIndex) {
+                return Immediate(offset);
+            }
+        }
+        return Operation(OperationCode::UAdd, NO_PRECISE, node, Immediate(offset));
+    }();
     return MakeNode<CbufNode>(index, final_offset);
 }
 

src/video_core/shader/shader_ir.h

@@ -316,7 +316,7 @@ private:
     void WriteLop3Instruction(NodeBlock& bb, Tegra::Shader::Register dest, Node op_a, Node op_b,
                               Node op_c, Node imm_lut, bool sets_cc);
 
-    Node TrackCbuf(Node tracked, const NodeBlock& code, s64 cursor) const;
+    std::tuple<Node, u32, u32> TrackCbuf(Node tracked, const NodeBlock& code, s64 cursor) const;
 
     std::optional<u32> TrackImmediate(Node tracked, const NodeBlock& code, s64 cursor) const;
 

src/video_core/shader/track.cpp

@@ -32,39 +32,44 @@ std::pair<Node, s64> FindOperation(const NodeBlock& code, s64 cursor,
     }
     return {};
 }
-} // namespace
+} // Anonymous namespace
 
-Node ShaderIR::TrackCbuf(Node tracked, const NodeBlock& code, s64 cursor) const {
+std::tuple<Node, u32, u32> ShaderIR::TrackCbuf(Node tracked, const NodeBlock& code,
+                                               s64 cursor) const {
     if (const auto cbuf = std::get_if<CbufNode>(&*tracked)) {
-        // Cbuf found, but it has to be immediate
-        return std::holds_alternative<ImmediateNode>(*cbuf->GetOffset()) ? tracked : nullptr;
+        // Constant buffer found, test if it's an immediate
+        const auto offset = cbuf->GetOffset();
+        if (const auto immediate = std::get_if<ImmediateNode>(&*offset)) {
+            return {tracked, cbuf->GetIndex(), immediate->GetValue()};
+        }
+        return {};
     }
     if (const auto gpr = std::get_if<GprNode>(&*tracked)) {
         if (gpr->GetIndex() == Tegra::Shader::Register::ZeroIndex) {
-            return nullptr;
+            return {};
         }
         // Reduce the cursor in one to avoid infinite loops when the instruction sets the same
         // register that it uses as operand
         const auto [source, new_cursor] = TrackRegister(gpr, code, cursor - 1);
         if (!source) {
-            return nullptr;
+            return {};
         }
         return TrackCbuf(source, code, new_cursor);
     }
     if (const auto operation = std::get_if<OperationNode>(&*tracked)) {
         for (std::size_t i = 0; i < operation->GetOperandsCount(); ++i) {
-            if (const auto found = TrackCbuf((*operation)[i], code, cursor)) {
-                // Cbuf found in operand
+            if (auto found = TrackCbuf((*operation)[i], code, cursor); std::get<0>(found)) {
+                // Cbuf found in operand.
                 return found;
             }
         }
-        return nullptr;
+        return {};
     }
     if (const auto conditional = std::get_if<ConditionalNode>(&*tracked)) {
         const auto& conditional_code = conditional->GetCode();
         return TrackCbuf(tracked, conditional_code, static_cast<s64>(conditional_code.size()));
     }
-    return nullptr;
+    return {};
 }
 
 std::optional<u32> ShaderIR::TrackImmediate(Node tracked, const NodeBlock& code, s64 cursor) const {