From c1cc63e5ff1f2a9b7621051475085cb0b6303ecb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alex=20R=C3=B8nne=20Petersen?= <alex@alexrp.com>
Date: Wed, 18 Sep 2024 03:33:08 +0200
Subject: [PATCH] libc: Work around LLVM's misassembly of `j <reg>` on mips r6.

See: https://github.com/ziglang/zig/issues/21315
---
 lib/libc/glibc/sysdeps/mips/mips32/crtn.S     | 6 ++++--
 lib/libc/glibc/sysdeps/mips/mips64/n32/crtn.S | 6 ++++--
 lib/libc/glibc/sysdeps/mips/mips64/n64/crtn.S | 6 ++++--
 lib/libc/glibc/sysdeps/unix/mips/sysdep.h     | 3 ++-
 lib/libc/musl/crt/mips/crtn.s                 | 6 ++++--
 lib/libc/musl/crt/mips64/crtn.s               | 6 ++++--
 6 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/lib/libc/glibc/sysdeps/mips/mips32/crtn.S b/lib/libc/glibc/sysdeps/mips/mips32/crtn.S
index 89ecbd9882..4fd4c745d9 100644
--- a/lib/libc/glibc/sysdeps/mips/mips32/crtn.S
+++ b/lib/libc/glibc/sysdeps/mips/mips32/crtn.S
@@ -42,7 +42,8 @@
 	lw $31,28($sp)
 	.set noreorder
 	.set nomacro
-	j $31
+	/* zig patch: j <reg> -> jr <reg> for https://github.com/ziglang/zig/issues/21315 */
+	jr $31
 	addiu $sp,$sp,32
 	.set macro
 	.set reorder
@@ -51,7 +52,8 @@
 	lw $31,28($sp)
 	.set noreorder
 	.set nomacro
-	j $31
+	/* zig patch: j <reg> -> jr <reg> for https://github.com/ziglang/zig/issues/21315 */
+	jr $31
 	addiu $sp,$sp,32
 	.set macro
 	.set reorder
diff --git a/lib/libc/glibc/sysdeps/mips/mips64/n32/crtn.S b/lib/libc/glibc/sysdeps/mips/mips64/n32/crtn.S
index 633d79cfad..f9a6c7ee4c 100644
--- a/lib/libc/glibc/sysdeps/mips/mips64/n32/crtn.S
+++ b/lib/libc/glibc/sysdeps/mips/mips64/n32/crtn.S
@@ -43,7 +43,8 @@
 	ld $28,0($sp)
 	.set noreorder
 	.set nomacro
-	j $31
+	/* zig patch: j <reg> -> jr <reg> for https://github.com/ziglang/zig/issues/21315 */
+	jr $31
 	addiu $sp,$sp,16
 	.set macro
 	.set reorder
@@ -53,7 +54,8 @@
 	ld $28,0($sp)
 	.set noreorder
 	.set nomacro
-	j $31
+	/* zig patch: j <reg> -> jr <reg> for https://github.com/ziglang/zig/issues/21315 */
+	jr $31
 	addiu $sp,$sp,16
 	.set macro
 	.set reorder
diff --git a/lib/libc/glibc/sysdeps/mips/mips64/n64/crtn.S b/lib/libc/glibc/sysdeps/mips/mips64/n64/crtn.S
index 99ed1e3263..2722b2812c 100644
--- a/lib/libc/glibc/sysdeps/mips/mips64/n64/crtn.S
+++ b/lib/libc/glibc/sysdeps/mips/mips64/n64/crtn.S
@@ -43,7 +43,8 @@
 	ld $28,0($sp)
 	.set noreorder
 	.set nomacro
-	j $31
+	/* zig patch: j <reg> -> jr <reg> for https://github.com/ziglang/zig/issues/21315 */
+	jr $31
 	daddiu $sp,$sp,16
 	.set macro
 	.set reorder
@@ -53,7 +54,8 @@
 	ld $28,0($sp)
 	.set noreorder
 	.set nomacro
-	j $31
+	/* zig patch: j <reg> -> jr <reg> for https://github.com/ziglang/zig/issues/21315 */
+	jr $31
 	daddiu $sp,$sp,16
 	.set macro
 	.set reorder
diff --git a/lib/libc/glibc/sysdeps/unix/mips/sysdep.h b/lib/libc/glibc/sysdeps/unix/mips/sysdep.h
index d1e0460260..54e92b26d0 100644
--- a/lib/libc/glibc/sysdeps/unix/mips/sysdep.h
+++ b/lib/libc/glibc/sysdeps/unix/mips/sysdep.h
@@ -39,7 +39,8 @@
 		.end	function;		        \
 		.size	function,.-function
 
-#define ret	j ra ; nop
+// zig patch: j <reg> -> jr <reg> for https://github.com/ziglang/zig/issues/21315
+#define ret	jr ra ; nop
 
 #undef PSEUDO_END
 #define PSEUDO_END(sym) cfi_endproc; .end sym; .size sym,.-sym
diff --git a/lib/libc/musl/crt/mips/crtn.s b/lib/libc/musl/crt/mips/crtn.s
index 506a04b78c..5146d83a0e 100644
--- a/lib/libc/musl/crt/mips/crtn.s
+++ b/lib/libc/musl/crt/mips/crtn.s
@@ -3,11 +3,13 @@
 .section .init
 	lw $gp,24($sp)
 	lw $ra,28($sp)
-	j $ra
+	# zig patch: j <reg> -> jr <reg> for https://github.com/ziglang/zig/issues/21315
+	jr $ra
 	addu $sp,$sp,32
 
 .section .fini
 	lw $gp,24($sp)
 	lw $ra,28($sp)
-	j $ra
+	# zig patch: j <reg> -> jr <reg> for https://github.com/ziglang/zig/issues/21315
+	jr $ra
 	addu $sp,$sp,32
diff --git a/lib/libc/musl/crt/mips64/crtn.s b/lib/libc/musl/crt/mips64/crtn.s
index f3930b2406..dc4dbb03ad 100644
--- a/lib/libc/musl/crt/mips64/crtn.s
+++ b/lib/libc/musl/crt/mips64/crtn.s
@@ -3,11 +3,13 @@
 .section .init
 	ld $gp,16($sp)
 	ld $ra,24($sp)
-	j $ra
+	# zig patch: j <reg> -> jr <reg> for https://github.com/ziglang/zig/issues/21315
+	jr $ra
 	daddu $sp,$sp,32
 
 .section .fini
 	ld $gp,16($sp)
 	ld $ra,24($sp)
-	j $ra
+	# zig patch: j <reg> -> jr <reg> for https://github.com/ziglang/zig/issues/21315
+	jr $ra
 	daddu $sp,$sp,32