// Copyright 2018 yuzu Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <algorithm>
#include <utility>
#include <variant>
#include "video_core/shader/shader_ir.h"
namespace VideoCommon::Shader {
namespace {
std::pair<Node, s64> FindOperation(const NodeBlock& code, s64 cursor,
OperationCode operation_code) {
for (; cursor >= 0; --cursor) {
const Node node = code[cursor];
if (const auto operation = std::get_if<OperationNode>(node)) {
if (operation->GetCode() == operation_code)
return {node, cursor};
}
if (const auto conditional = std::get_if<ConditionalNode>(node)) {
const auto& code = conditional->GetCode();
const auto [found, internal_cursor] =
FindOperation(code, static_cast<s64>(code.size() - 1), operation_code);
if (found)
return {found, cursor};
}
}
return {};
}
} // namespace
Node ShaderIR::TrackCbuf(Node tracked, const NodeBlock& code, s64 cursor) {
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;
}
if (const auto gpr = std::get_if<GprNode>(tracked)) {
if (gpr->GetIndex() == Tegra::Shader::Register::ZeroIndex) {
return nullptr;
}
// 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 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
return found;
}
}
return nullptr;
}
if (const auto conditional = std::get_if<ConditionalNode>(tracked)) {
const auto& code = conditional->GetCode();
return TrackCbuf(tracked, code, static_cast<s64>(code.size()));
}
return nullptr;
}
std::pair<Node, s64> ShaderIR::TrackRegister(const GprNode* tracked, const NodeBlock& code,
s64 cursor) {
for (; cursor >= 0; --cursor) {
const auto [found_node, new_cursor] = FindOperation(code, cursor, OperationCode::Assign);
if (!found_node) {
return {};
}
const auto operation = std::get_if<OperationNode>(found_node);
ASSERT(operation);
const auto& target = (*operation)[0];
if (const auto gpr_target = std::get_if<GprNode>(target)) {
if (gpr_target->GetIndex() == tracked->GetIndex()) {
return {(*operation)[1], new_cursor};
}
}
}
return {};
}
} // namespace VideoCommon::Shader
