Fix nullptr deref for rebased method

Macro code is just uploaded sequentially from a starting address, however that does not mean the entry point for the macro is at that address. This PR adds preliminary support for executing macros in the middle of our cached code.

src/video_core/macro/macro.cpp

@@ -2,6 +2,7 @@
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
+#include <optional>
 #include <boost/container_hash/hash.hpp>
 #include "common/assert.h"
 #include "common/logging/log.h"
@@ -35,22 +36,40 @@ void MacroEngine::Execute(Engines::Maxwell3D& maxwell3d, u32 method,
         }
     } else {
         // Macro not compiled, check if it's uploaded and if so, compile it
-        auto macro_code = uploaded_macro_code.find(method);
+        std::optional<u32> mid_method = std::nullopt;
+        const auto macro_code = uploaded_macro_code.find(method);
         if (macro_code == uploaded_macro_code.end()) {
-            UNREACHABLE_MSG("Macro 0x{0:x} was not uploaded", method);
-            return;
+            for (const auto& [method_base, code] : uploaded_macro_code) {
+                if (method >= method_base && (method - method_base) < code.size()) {
+                    mid_method = method_base;
+                    break;
+                }
+            }
+            if (!mid_method.has_value()) {
+                UNREACHABLE_MSG("Macro 0x{0:x} was not uploaded", method);
+                return;
+            }
         }
         auto& cache_info = macro_cache[method];
-        cache_info.hash = boost::hash_value(macro_code->second);
-        cache_info.lle_program = Compile(macro_code->second);
+
+        if (!mid_method.has_value()) {
+            cache_info.lle_program = Compile(macro_code->second);
+            cache_info.hash = boost::hash_value(macro_code->second);
+        } else {
+            const auto& macro_cached = uploaded_macro_code[mid_method.value()];
+            const auto rebased_method = method - mid_method.value();
+            auto& code = uploaded_macro_code[method];
+            code.resize(macro_cached.size() - rebased_method);
+            std::memcpy(code.data(), macro_cached.data() + rebased_method,
+                        code.size() * sizeof(u32));
+            cache_info.hash = boost::hash_value(code);
+            cache_info.lle_program = Compile(code);
+        }
 
         auto hle_program = hle_macros->GetHLEProgram(cache_info.hash);
         if (hle_program.has_value()) {
             cache_info.has_hle_program = true;
             cache_info.hle_program = std::move(hle_program.value());
-        }
-
-        if (cache_info.has_hle_program) {
             cache_info.hle_program->Execute(parameters, method);
         } else {
             cache_info.lle_program->Execute(parameters, method);