From 2a152a9676ed57b7b913ad80b556b5e569ada908 Mon Sep 17 00:00:00 2001
From: Tharo <17233964+Thar0@users.noreply.github.com>
Date: Sun, 22 Dec 2024 23:24:47 +0000
Subject: [PATCH] Apply the NORETURN attribute to functions that do not return
 (#1768)

* Apply the NORETURN attribute to functions that do not return

* Add NORETURN to debug.c functions
---
 include/attributes.h     | 6 ++++++
 include/fault.h          | 5 +++--
 include/functions.h      | 2 +-
 include/libu64/debug.h   | 6 ++++--
 src/boot/fault.c         | 8 ++++++--
 src/boot/libu64/debug.c  | 4 ++--
 src/code/code_80183070.c | 3 ++-
 7 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/include/attributes.h b/include/attributes.h
index 9b3832fcb2..2c555930e9 100644
--- a/include/attributes.h
+++ b/include/attributes.h
@@ -14,4 +14,10 @@
 #define NO_REORDER   __attribute__((no_reorder))
 #define SECTION_DATA __attribute__((section(".data")))
 
+#ifdef __GNUC__
+#define UNREACHABLE() __builtin_unreachable()
+#else
+#define UNREACHABLE()
+#endif
+
 #endif
diff --git a/include/fault.h b/include/fault.h
index 8ddd759c60..d7fb2228a2 100644
--- a/include/fault.h
+++ b/include/fault.h
@@ -2,6 +2,7 @@
 #define FAULT_H
 
 #include "ultra64.h"
+#include "attributes.h"
 
 #include "stdarg.h"
 #include "stdint.h"
@@ -60,8 +61,8 @@ void Fault_Init(void);
 
 // Fatal Errors
 
-void Fault_AddHungupAndCrashImpl(const char* exp1, const char* exp2);
-void Fault_AddHungupAndCrash(const char* file, s32 line);
+NORETURN void Fault_AddHungupAndCrashImpl(const char* exp1, const char* exp2);
+NORETURN void Fault_AddHungupAndCrash(const char* file, s32 line);
 
 // Client Registration
 
diff --git a/include/functions.h b/include/functions.h
index e379137ae8..419c392134 100644
--- a/include/functions.h
+++ b/include/functions.h
@@ -25,7 +25,7 @@ void Room_Draw(PlayState* play, Room* room, u32 flags);
 
 void Room_FinishRoomChange(PlayState* play, RoomContext* roomCtx);
 
-void func_80183070(void);
+NORETURN void func_80183070(void);
 
 AudioTask* AudioThread_Update(void);
 void AudioThread_QueueCmdF32(u32 opArgs, f32 data);
diff --git a/include/libu64/debug.h b/include/libu64/debug.h
index 5bcae690ce..98edb407d6 100644
--- a/include/libu64/debug.h
+++ b/include/libu64/debug.h
@@ -1,7 +1,9 @@
 #ifndef LIBU64_DEBUG_H
 #define LIBU64_DEBUG_H
 
-void _dbg_hungup(const char* file, int lineNum);
-void Reset(void);
+#include "../attributes.h"
+
+NORETURN void _dbg_hungup(const char* file, int lineNum);
+NORETURN void Reset(void);
 
 #endif
diff --git a/src/boot/fault.c b/src/boot/fault.c
index 8f4739e04e..15a77f03b1 100644
--- a/src/boot/fault.c
+++ b/src/boot/fault.c
@@ -1114,19 +1114,23 @@ void Fault_HangupFaultClient(const char* exp1, const char* exp2) {
  * error occurs. The parameters specify two messages detailing the error, one
  * or both may be NULL.
  */
-void Fault_AddHungupAndCrashImpl(const char* exp1, const char* exp2) {
+NORETURN void Fault_AddHungupAndCrashImpl(const char* exp1, const char* exp2) {
     FaultClient client;
     s32 pad;
 
     Fault_AddClient(&client, (void*)Fault_HangupFaultClient, (void*)exp1, (void*)exp2);
     *(u32*)0x11111111 = 0; // trigger an exception via unaligned memory access
+
+    // Since the above line triggers an exception and transfers execution to the fault handler
+    // this function does not return and the rest of the function is unreachable.
+    UNREACHABLE();
 }
 
 /**
  * Like `Fault_AddHungupAndCrashImpl`, however provides a fixed message containing
  * file and line number
  */
-void Fault_AddHungupAndCrash(const char* file, s32 line) {
+NORETURN void Fault_AddHungupAndCrash(const char* file, s32 line) {
     char msg[0x100];
 
     sprintf(msg, "HungUp %s:%d", file, line);
diff --git a/src/boot/libu64/debug.c b/src/boot/libu64/debug.c
index 3933b585e0..7398275472 100644
--- a/src/boot/libu64/debug.c
+++ b/src/boot/libu64/debug.c
@@ -1,11 +1,11 @@
 #include "global.h"
 #include "fault.h"
 
-void _dbg_hungup(const char* file, int lineNum) {
+NORETURN void _dbg_hungup(const char* file, int lineNum) {
     osGetThreadId(NULL);
     Fault_AddHungupAndCrash(file, lineNum);
 }
 
-void Reset(void) {
+NORETURN void Reset(void) {
     Fault_AddHungupAndCrash("Reset", 0);
 }
diff --git a/src/code/code_80183070.c b/src/code/code_80183070.c
index 974cdd4a3b..bb3d2803ee 100644
--- a/src/code/code_80183070.c
+++ b/src/code/code_80183070.c
@@ -1,6 +1,7 @@
 #include "libc64/sleep.h"
+#include "attributes.h"
 
-void func_80183070(void) {
+NORETURN void func_80183070(void) {
     for (;;) {
         msleep(1000);
     }