From 8e7847f6d959e25b7cda3ebe9289c85594a44215 Mon Sep 17 00:00:00 2001
From: "Unknown W. Brackets" <checkins@unknownbrackets.org>
Date: Sun, 21 Aug 2022 14:09:52 -0700
Subject: [PATCH] UI: Show return address for exec crashes.

---
 Core/Core.cpp                  |  7 +++++--
 Core/Core.h                    |  3 ++-
 Core/MIPS/IR/IRInterpreter.cpp |  2 +-
 Core/MIPS/MIPSInt.cpp          |  2 +-
 UI/EmuScreen.cpp               | 17 +++++++++++++----
 5 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/Core/Core.cpp b/Core/Core.cpp
index e723107d3034..52a1df8f4c1a 100644
--- a/Core/Core.cpp
+++ b/Core/Core.cpp
@@ -487,16 +487,19 @@ void Core_ExecException(u32 address, u32 pc, ExecExceptionType type) {
 	e.exec_type = type;
 	e.address = address;
 	e.pc = pc;
-	Core_EnableStepping(true, "cpu.exception", pc);
+	// This just records the closest value that could be useful as reference.
+	e.ra = currentMIPS->r[MIPS_REG_RA];
+	Core_EnableStepping(true, "cpu.exception", address);
 }
 
-void Core_Break() {
+void Core_Break(u32 pc) {
 	ERROR_LOG(CPU, "BREAK!");
 
 	ExceptionInfo &e = g_exceptionInfo;
 	e = {};
 	e.type = ExceptionType::BREAK;
 	e.info = "";
+	e.pc = pc;
 
 	if (!g_Config.bIgnoreBadMemAccess) {
 		Core_EnableStepping(true, "cpu.breakInstruction", currentMIPS->pc);
diff --git a/Core/Core.h b/Core/Core.h
index 894accd6aeed..d706e7afec78 100644
--- a/Core/Core.h
+++ b/Core/Core.h
@@ -106,7 +106,7 @@ void Core_MemoryException(u32 address, u32 pc, MemoryExceptionType type);
 void Core_MemoryExceptionInfo(u32 address, u32 pc, MemoryExceptionType type, std::string additionalInfo);
 
 void Core_ExecException(u32 address, u32 pc, ExecExceptionType type);
-void Core_Break();
+void Core_Break(u32 pc);
 // Call when loading save states, etc.
 void Core_ResetException();
 
@@ -125,6 +125,7 @@ struct ExceptionInfo {
 	MemoryExceptionType memory_type;
 	uint32_t pc;
 	uint32_t address;
+	uint32_t ra = 0;
 
 	// Reuses pc and address from memory type, where address is the failed destination.
 	ExecExceptionType exec_type;
diff --git a/Core/MIPS/IR/IRInterpreter.cpp b/Core/MIPS/IR/IRInterpreter.cpp
index bc97b52b732a..27b0ba0ca328 100644
--- a/Core/MIPS/IR/IRInterpreter.cpp
+++ b/Core/MIPS/IR/IRInterpreter.cpp
@@ -998,7 +998,7 @@ u32 IRInterpret(MIPSState *mips, const IRInst *inst, int count) {
 		}
 
 		case IROp::Break:
-			Core_Break();
+			Core_Break(mips->pc);
 			return mips->pc + 4;
 
 		case IROp::SetCtrlVFPU:
diff --git a/Core/MIPS/MIPSInt.cpp b/Core/MIPS/MIPSInt.cpp
index 99cad4df3e62..46585b69a9ca 100644
--- a/Core/MIPS/MIPSInt.cpp
+++ b/Core/MIPS/MIPSInt.cpp
@@ -157,7 +157,7 @@ namespace MIPSInt
 	void Int_Break(MIPSOpcode op)
 	{
 		Reporting::ReportMessage("BREAK instruction hit");
-		Core_Break();
+		Core_Break(PC);
 		PC += 4;
 	}
 
diff --git a/UI/EmuScreen.cpp b/UI/EmuScreen.cpp
index aa0857646704..1b98b91bb8d6 100644
--- a/UI/EmuScreen.cpp
+++ b/UI/EmuScreen.cpp
@@ -1209,16 +1209,25 @@ PC: %08x
 	} else if (info.type == ExceptionType::BAD_EXEC_ADDR) {
 		snprintf(statbuf, sizeof(statbuf), R"(
 Destination: %s to %08x
-PC: %08x)",
+PC: %08x
+RA: %08x)",
 			ExecExceptionTypeAsString(info.exec_type),
 			info.address,
-			info.pc);
+			info.pc,
+			info.ra);
 		ctx->Draw()->DrawTextShadow(ubuntu24, statbuf, x, y, 0xFFFFFFFF);
 		y += 180;
-	} else {
+	} else if (info.type == ExceptionType::BREAK) {
 		snprintf(statbuf, sizeof(statbuf), R"(
 BREAK
-)");
+PC: %08x
+)", info.pc);
+		ctx->Draw()->DrawTextShadow(ubuntu24, statbuf, x, y, 0xFFFFFFFF);
+		y += 180;
+	} else {
+		snprintf(statbuf, sizeof(statbuf), R"(
+Invalid / Unknown (%d)
+)", (int)info.type);
 		ctx->Draw()->DrawTextShadow(ubuntu24, statbuf, x, y, 0xFFFFFFFF);
 		y += 180;
 	}