shader_ir: Implement a new shader scanner

src/video_core/shader/control_flow.h

@@ -0,0 +1,55 @@
+#pragma once
+
+#include <cstring>
+#include <list>
+#include <optional>
+#include <vector>
+
+#include "video_core/engines/shader_bytecode.h"
+#include "video_core/shader/shader_ir.h"
+
+namespace VideoCommon::Shader {
+
+using Tegra::Shader::ConditionCode;
+using Tegra::Shader::Pred;
+
+constexpr s32 exit_branch = -1;
+
+struct Condition {
+    Pred predicate{Pred::UnusedIndex};
+    ConditionCode cc{ConditionCode::T};
+
+    bool IsUnconditional() const {
+        return (predicate == Pred::UnusedIndex) && (cc == ConditionCode::T);
+    }
+};
+
+struct ShaderBlock {
+    ShaderBlock() {}
+    ShaderBlock(const ShaderBlock& sb) = default;
+    u32 start{};
+    u32 end{};
+    struct Branch {
+        Condition cond{};
+        bool kills{};
+        s32 address{};
+        bool operator==(const Branch& b) const {
+            return std::memcmp(this, &b, sizeof(Branch)) == 0;
+        }
+    } branch;
+    bool operator==(const ShaderBlock& sb) const {
+        return std::memcmp(this, &sb, sizeof(ShaderBlock)) == 0;
+    }
+};
+
+struct ShaderCharacteristics {
+    std::list<ShaderBlock> blocks;
+    bool decompilable{};
+    u32 start;
+    u32 end;
+};
+
+bool ScanFlow(const ProgramCode& program_code, u32 program_size, u32 start_address,
+              ShaderCharacteristics& result_out);
+
+} // namespace VideoCommon::Shader