Debugger: Rewind SPU captures

Very basic implementation, can be improved.

rpcs3/Emu/Cell/SPUThread.cpp

@@ -1722,6 +1722,20 @@ void spu_thread::serialize_common(utils::serial& ar)
 		, run_ctrl, exit_status.data, status_npc.raw().status, ch_dec_start_timestamp, ch_dec_value, is_dec_frozen);
 
 	ar(std::span(mfc_queue, mfc_size));
+
+	u32 vals[4]{};
+
+	if (ar.is_writing())
+	{
+		const u8 count = ch_in_mbox.try_read(vals);
+		ar(count, std::span(vals, count));
+	}
+	else
+	{
+		const u8 count = ar;
+		ar(std::span(vals, count));
+		ch_in_mbox.set_values(count, vals[0], vals[1], vals[2], vals[3]);
+	}
 }
 
 spu_thread::spu_thread(utils::serial& ar, lv2_spu_group* group)
@@ -1769,13 +1783,6 @@ spu_thread::spu_thread(utils::serial& ar, lv2_spu_group* group)
 
 	serialize_common(ar);
 
-	{
-		u32 vals[4]{};
-		const u8 count = ar;
-		ar(std::span(vals, count));
-		ch_in_mbox.set_values(count, vals[0], vals[1], vals[2], vals[3]);
-	}
-
 	status_npc.raw().npc = pc | u8{interrupts_enabled};
 
 	if (get_type() == spu_type::threaded)
@@ -1827,12 +1834,6 @@ void spu_thread::save(utils::serial& ar)
 
 	serialize_common(ar);
 
-	{
-		u32 vals[4]{};
-		const u8 count = ch_in_mbox.try_read(vals);
-		ar(count, std::span(vals, count));
-	}
-
 	if (get_type() == spu_type::threaded)
 	{
 		for (const auto& [key, q] : spuq)
@@ -5339,8 +5340,10 @@ void spu_thread::fast_call(u32 ls_addr)
 	gpr[1]._u32[3] = old_stack;
 }
 
-bool spu_thread::capture_local_storage() const
+bool spu_thread::capture_state()
 {
+	ensure(state & cpu_flag::wait);
+
 	spu_exec_object spu_exec;
 
 	// Save data as an executable segment, even the SPU stack
@@ -5424,6 +5427,50 @@ bool spu_thread::capture_local_storage() const
 	}
 
 	spu_log.success("SPU Local Storage image saved to '%s'", elf_path);
+
+	if (g_cfg.core.spu_decoder == spu_decoder_type::asmjit || g_cfg.core.spu_decoder == spu_decoder_type::llvm)
+	{
+		return true;
+	}
+
+	auto& rewind = rewind_captures[current_rewind_capture_idx++ % rewind_captures.size()];
+
+	if (rewind)
+	{
+		spu_log.error("Due to resource limits the 16th SPU rewind capture is being overwritten with a new one. (free the most recent by loading it)");
+		rewind.reset();
+	}
+
+	rewind = std::make_shared<utils::serial>();
+	(*rewind)(std::span(prog.bin.data(), prog.bin.size())); // span serialization doesn't remember size which is what we need
+	serialize_common(*rewind);
+
+	// TODO: Save and restore decrementer state properly
+
+	spu_log.success("SPU rewind image has been saved in memory. (%d free slots left)", std::count_if(rewind_captures.begin(), rewind_captures.end(), FN(!x.operator bool())));
+	return true;
+}
+
+bool spu_thread::try_load_debug_capture()
+{
+	if (cpu_flag::wait - state)
+	{
+		return false;
+	}
+
+	auto rewind = std::move(rewind_captures[(current_rewind_capture_idx - 1) % rewind_captures.size()]);
+
+	if (!rewind)
+	{
+		return false;
+	}
+
+	rewind->set_reading_state();
+	(*rewind)(std::span(ls, SPU_LS_SIZE)); // span serialization doesn't remember size which is what we need
+	serialize_common(*rewind);
+	current_rewind_capture_idx--;
+
+	spu_log.success("Last SPU rewind image has been loaded.");
 	return true;
 }
 

rpcs3/Emu/Cell/SPUThread.h

@@ -813,7 +813,11 @@ public:
 
 	void fast_call(u32 ls_addr);
 
-	bool capture_local_storage() const;
+	std::array<std::shared_ptr<utils::serial>, 32> rewind_captures; // shared_ptr to avoid header inclusion
+	u8 current_rewind_capture_idx = 0;
+
+	bool capture_state();
+	bool try_load_debug_capture();
 	void wakeup_delay(u32 div = 1) const;
 
 	// Convert specified SPU LS address to a pointer of specified (possibly converted to BE) type

rpcs3/rpcs3qt/debugger_frame.cpp

@@ -30,6 +30,7 @@
 #include <QVBoxLayout>
 #include <QTimer>
 #include <QCheckBox>
+#include <QMessageBox>
 #include <charconv>
 
 #include "util/asm.hpp"
@@ -324,6 +325,7 @@ void debugger_frame::keyPressEvent(QKeyEvent* event)
 			"\nKeys Ctrl+B: Open breakpoints settings."
 			"\nKeys Ctrl+S: Search memory string utility."
 			"\nKeys Alt+S: Capture SPU images of selected SPU."
+			"\nKeys Alt+R: Load last saved SPU state capture."
 			"\nKey D: SPU MFC commands logger, MFC debug setting must be enabled."
 			"\nKey D: Also PPU calling history logger, interpreter and non-zero call history size must be used."
 			"\nKey E: Instruction Editor: click on the instruction you want to modify, then press E."
@@ -594,6 +596,12 @@ void debugger_frame::keyPressEvent(QKeyEvent* event)
 
 			if (cpu->id_type() == 1 || cpu->id_type() == 2)
 			{
+				if (cpu->id_type() == 2 && modifiers & Qt::AltModifier)
+				{
+					static_cast<spu_thread*>(cpu)->try_load_debug_capture();
+					return;
+				}
+
 				if (!m_reg_editor)
 				{
 					m_reg_editor = new register_editor_dialog(this, m_disasm.get(), make_check_cpu(cpu));
@@ -615,7 +623,13 @@ void debugger_frame::keyPressEvent(QKeyEvent* event)
 					return;
 				}
 
-				static_cast<spu_thread*>(cpu)->capture_local_storage();
+				if (!cpu->state.all_of(cpu_flag::wait + cpu_flag::dbg_pause))
+				{
+					QMessageBox::warning(this, QObject::tr("Pause the SPU Thread!"), QObject::tr("Cannot perform SPU capture due to the thread need manual pausing!"));
+					return;
+				}
+
+				static_cast<spu_thread*>(cpu)->capture_state();
 			}
 			return;
 		}