Merge pull request #6585 from ameerj/hades

Shader Decompiler Rewrite

1 files changed, 169 insertions, 0 deletions

diff --git a/src/shader_recompiler/frontend/maxwell/control_flow.h b/src/shader_recompiler/frontend/maxwell/control_flow.h
new file mode 100644
index 000000000..a6bd3e196
--- /dev/null
+++ b/src/shader_recompiler/frontend/maxwell/control_flow.h
@@ -0,0 +1,169 @@
+// Copyright 2021 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <compare>
+#include <optional>
+#include <span>
+#include <string>
+#include <vector>
+
+#include <boost/container/small_vector.hpp>
+#include <boost/intrusive/set.hpp>
+
+#include "shader_recompiler/environment.h"
+#include "shader_recompiler/frontend/ir/condition.h"
+#include "shader_recompiler/frontend/maxwell/instruction.h"
+#include "shader_recompiler/frontend/maxwell/location.h"
+#include "shader_recompiler/frontend/maxwell/opcodes.h"
+#include "shader_recompiler/object_pool.h"
+
+namespace Shader::Maxwell::Flow {
+
+struct Block;
+
+using FunctionId = size_t;
+
+enum class EndClass {
+    Branch,
+    IndirectBranch,
+    Call,
+    Exit,
+    Return,
+    Kill,
+};
+
+enum class Token {
+    SSY,
+    PBK,
+    PEXIT,
+    PRET,
+    PCNT,
+    PLONGJMP,
+};
+
+struct StackEntry {
+    auto operator<=>(const StackEntry&) const noexcept = default;
+
+    Token token;
+    Location target;
+};
+
+class Stack {
+public:
+    void Push(Token token, Location target);
+    [[nodiscard]] std::pair<Location, Stack> Pop(Token token) const;
+    [[nodiscard]] std::optional<Location> Peek(Token token) const;
+    [[nodiscard]] Stack Remove(Token token) const;
+
+private:
+    boost::container::small_vector<StackEntry, 3> entries;
+};
+
+struct IndirectBranch {
+    Block* block;
+    u32 address;
+};
+
+struct Block : boost::intrusive::set_base_hook<
+                   // Normal link is ~2.5% faster compared to safe link
+                   boost::intrusive::link_mode<boost::intrusive::normal_link>> {
+    [[nodiscard]] bool Contains(Location pc) const noexcept;
+
+    bool operator<(const Block& rhs) const noexcept {
+        return begin < rhs.begin;
+    }
+
+    Location begin;
+    Location end;
+    EndClass end_class{};
+    IR::Condition cond{};
+    Stack stack;
+    Block* branch_true{};
+    Block* branch_false{};
+    FunctionId function_call{};
+    Block* return_block{};
+    IR::Reg branch_reg{};
+    s32 branch_offset{};
+    std::vector<IndirectBranch> indirect_branches;
+};
+
+struct Label {
+    Location address;
+    Block* block;
+    Stack stack;
+};
+
+struct Function {
+    explicit Function(ObjectPool<Block>& block_pool, Location start_address);
+
+    Location entrypoint;
+    boost::container::small_vector<Label, 16> labels;
+    boost::intrusive::set<Block> blocks;
+};
+
+class CFG {
+    enum class AnalysisState {
+        Branch,
+        Continue,
+    };
+
+public:
+    explicit CFG(Environment& env, ObjectPool<Block>& block_pool, Location start_address,
+                 bool exits_to_dispatcher = false);
+
+    CFG& operator=(const CFG&) = delete;
+    CFG(const CFG&) = delete;
+
+    CFG& operator=(CFG&&) = delete;
+    CFG(CFG&&) = delete;
+
+    [[nodiscard]] std::string Dot() const;
+
+    [[nodiscard]] std::span<const Function> Functions() const noexcept {
+        return std::span(functions.data(), functions.size());
+    }
+    [[nodiscard]] std::span<Function> Functions() noexcept {
+        return std::span(functions.data(), functions.size());
+    }
+
+    [[nodiscard]] bool ExitsToDispatcher() const {
+        return exits_to_dispatcher;
+    }
+
+private:
+    void AnalyzeLabel(FunctionId function_id, Label& label);
+
+    /// Inspect already visited blocks.
+    /// Return true when the block has already been visited
+    bool InspectVisitedBlocks(FunctionId function_id, const Label& label);
+
+    AnalysisState AnalyzeInst(Block* block, FunctionId function_id, Location pc);
+
+    void AnalyzeCondInst(Block* block, FunctionId function_id, Location pc, EndClass insn_end_class,
+                         IR::Condition cond);
+
+    /// Return true when the branch instruction is confirmed to be a branch
+    bool AnalyzeBranch(Block* block, FunctionId function_id, Location pc, Instruction inst,
+                       Opcode opcode);
+
+    void AnalyzeBRA(Block* block, FunctionId function_id, Location pc, Instruction inst,
+                    bool is_absolute);
+    AnalysisState AnalyzeBRX(Block* block, Location pc, Instruction inst, bool is_absolute,
+                             FunctionId function_id);
+    AnalysisState AnalyzeEXIT(Block* block, FunctionId function_id, Location pc, Instruction inst);
+
+    /// Return the branch target block id
+    Block* AddLabel(Block* block, Stack stack, Location pc, FunctionId function_id);
+
+    Environment& env;
+    ObjectPool<Block>& block_pool;
+    boost::container::small_vector<Function, 1> functions;
+    Location program_start;
+    bool exits_to_dispatcher{};
+    Block* dispatch_block{};
+};
+
+} // namespace Shader::Maxwell::Flow