From 8acd1bd9909a684f6339af431190fabb6443ecdd Mon Sep 17 00:00:00 2001
From: xensik <xensik@pm.me>
Date: Sat, 21 Dec 2024 15:19:24 +0100
Subject: [PATCH] t6: merge old compiler fixes as flag

---
 include/xsk/arc/context.hpp |  4 ++++
 src/arc/decompiler.cpp      | 21 ++++++++++++++++++---
 src/arc/disassembler.cpp    | 11 +++++++++++
 src/tool/main.cpp           |  4 ++++
 4 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/include/xsk/arc/context.hpp b/include/xsk/arc/context.hpp
index d57741c6..a0a8db35 100644
--- a/include/xsk/arc/context.hpp
+++ b/include/xsk/arc/context.hpp
@@ -35,6 +35,9 @@ struct context
     auto compiler() -> compiler& { return compiler_; }
     auto decompiler() -> decompiler& { return decompiler_; }
 
+    auto fixup(bool value) -> void { fixup_ = value; }
+    auto fixup() const -> bool { return fixup_; }
+
     auto init(arc::build build, fs_callback callback) -> void;
     auto cleanup() -> void;
     auto engine_name() const -> std::string_view;
@@ -62,6 +65,7 @@ struct context
     arc::disassembler disassembler_;
     arc::compiler compiler_;
     arc::decompiler decompiler_;
+    bool fixup_{ false };
 
     fs_callback fs_callback_;
     std::unordered_map<opcode, std::string_view> opcode_map_;
diff --git a/src/arc/decompiler.cpp b/src/arc/decompiler.cpp
index fe8bcc40..7ae0c87d 100644
--- a/src/arc/decompiler.cpp
+++ b/src/arc/decompiler.cpp
@@ -304,8 +304,23 @@ auto decompiler::decompile_instruction(instruction const& inst, bool last) -> vo
         }
         case opcode::OP_EvalLocalVariableCached:
         {
-            stack_.push(expr_identifier::make(loc, locals_.at(std::stoi(inst.data[0]))));
-            break;
+            if (!ctx_->fixup())
+            {
+                stack_.push(expr_identifier::make(loc, locals_.at(std::stoi(inst.data[0]))));
+                break;
+            }
+            else // fix old compiler bug
+            {
+                try
+                {
+                    stack_.push(expr_identifier::make(loc, locals_.at(std::stoi(inst.data[0]))));
+                }
+                catch (const std::exception&)
+                {
+                    stack_.push(expr_identifier::make(loc, "broken_code!!"));
+                }
+                break;
+            }
         }
         case opcode::OP_EvalArray:
         {
@@ -1582,7 +1597,7 @@ auto decompiler::decompile_inf(stmt_list& stm, usize begin, usize end) -> void
     auto save = locs_;
     locs_.brk = last_location_index(stm, end) ? locs_.end : stm.list[end + 1]->label();
     locs_.end = stm.list[end]->label();
-    locs_.cnt = stm.list[end]->label();
+    locs_.cnt = stm.list[ctx_->fixup() ? begin : end]->label(); // fix old compiler bug
 
     auto loc = stm.list[begin]->loc();
 
diff --git a/src/arc/disassembler.cpp b/src/arc/disassembler.cpp
index ed184294..62c16d74 100644
--- a/src/arc/disassembler.cpp
+++ b/src/arc/disassembler.cpp
@@ -81,6 +81,13 @@ auto disassembler::disassemble(u8 const* data, usize data_size) -> assembly::ptr
     header_.flags = script_.read<u8>();
 
     auto string_pool = std::map<usize, std::string>{};
+
+    // fix old compiler bug
+    if (ctx_->fixup())
+    {
+        string_pool.insert({ 0x3E, "" });
+    }
+
     script_.pos((ctx_->props() & props::headerxx) ? header_size_v3 : (ctx_->props() & props::header72) ? header_size_v2 : header_size_v1);
 
     while (script_.pos() < header_.include_offset)
@@ -296,6 +303,10 @@ auto disassembler::disassemble(u8 const* data, usize data_size) -> assembly::ptr
                 }
             }
         }
+        else if (ctx_->fixup() && header_.cseg_size == 0) // fix old compiler bug
+        {
+            entry->size = (header_.imports_offset) - entry->offset;
+        }
         else
         {
             entry->size = (header_.cseg_offset + header_.cseg_size) - entry->offset;
diff --git a/src/tool/main.cpp b/src/tool/main.cpp
index 8f4170b0..0544c279 100644
--- a/src/tool/main.cpp
+++ b/src/tool/main.cpp
@@ -770,6 +770,7 @@ namespace arc
 
 std::map<game, std::map<mach, std::unique_ptr<context>>> contexts;
 std::map<mode, std::function<result(game game, mach mach, fs::path const& file, fs::path rel)>> funcs;
+bool t6fixup = false;
 
 auto assemble_file(game game, mach mach, fs::path const& file, fs::path rel) -> result
 {
@@ -953,6 +954,7 @@ auto init_t6(mach mach, bool dev) -> void
         {
             contexts[game::t6][mach] = std::make_unique<t6::pc::context>();
             contexts[game::t6][mach]->init(dev ? build::dev : build::prod, fs_read);
+            contexts[game::t6][mach]->fixup(t6fixup);
             break;
         }
         case mach::ps3:
@@ -1207,6 +1209,7 @@ auto main(u32 argc, char** argv) -> result
         ("y,dry", "Dry run (do not write files).", cxxopts::value<bool>()->implicit_value("true"))
         ("d,dev", "Enable developer mode (dev blocks & generate bytecode map).", cxxopts::value<bool>()->implicit_value("true"))
         ("z,zonetool", "Enable zonetool mode (use .cgsc files).", cxxopts::value<bool>()->implicit_value("true"))
+        ("t6fixup", "Decompile t6 files from broken compilers", cxxopts::value<bool>()->implicit_value("true"))
         ("h,help", "Display help.")
         ("v,version", "Display version.");
 
@@ -1262,6 +1265,7 @@ auto main(u32 argc, char** argv) -> result
         auto mach = mach::_;
         auto dev = result["dev"].as<bool>();
         gsc::zonetool = result["zonetool"].as<bool>();
+        arc::t6fixup = result["t6fixup"].as<bool>();
         dry_run = result["dry"].as<bool>();
 
         if(!parse_mode(mode_arg, mode))