From f14ebe71015dd58d02dda740febfab851fbe4983 Mon Sep 17 00:00:00 2001
From: Datong Sun <datong.sun@konghq.com>
Date: Mon, 11 Sep 2023 16:05:12 +0800
Subject: [PATCH] chore(patches): apply the LuaJIT ARM64 LDP/STP fusion fix
 from LuaJIT (#11537)

upstream

https://github.com/LuaJIT/LuaJIT/commit/b8c6ccd50c61b7a2df5123ddc5a85ac7d089542b

KAG-2473

(cherry picked from commit b0ca4241bb7a51089981c7b2ff90191f9b063740)
---
 .../kong/luajit_ldp_stp_fusion.yaml           |  6 +++
 ...uaJIT-2.1-20220411_06_ldp_stp_fusion.patch | 46 +++++++++++++++++++
 2 files changed, 52 insertions(+)
 create mode 100644 CHANGELOG/unreleased/kong/luajit_ldp_stp_fusion.yaml
 create mode 100644 build/openresty/patches/LuaJIT-2.1-20220411_06_ldp_stp_fusion.patch

diff --git a/CHANGELOG/unreleased/kong/luajit_ldp_stp_fusion.yaml b/CHANGELOG/unreleased/kong/luajit_ldp_stp_fusion.yaml
new file mode 100644
index 000000000000..d613d1f1601a
--- /dev/null
+++ b/CHANGELOG/unreleased/kong/luajit_ldp_stp_fusion.yaml
@@ -0,0 +1,6 @@
+message: "Fix incorrect LuaJIT LDP/STP fusion on ARM64 which may sometimes cause incorrect logic"
+type: dependency
+scope: Core
+prs:
+jiras:
+  - "KAG-2473"
diff --git a/build/openresty/patches/LuaJIT-2.1-20220411_06_ldp_stp_fusion.patch b/build/openresty/patches/LuaJIT-2.1-20220411_06_ldp_stp_fusion.patch
new file mode 100644
index 000000000000..ea36afd13382
--- /dev/null
+++ b/build/openresty/patches/LuaJIT-2.1-20220411_06_ldp_stp_fusion.patch
@@ -0,0 +1,46 @@
+From b8c6ccd50c61b7a2df5123ddc5a85ac7d089542b Mon Sep 17 00:00:00 2001
+From: Mike Pall <mike>
+Date: Sat, 9 Sep 2023 18:01:37 +0200
+Subject: [PATCH] ARM64: Fix LDP/STP fusion (again).
+
+Reported and analyzed by Zhongwei Yao. Fix by Peter Cawley. #1075
+---
+ src/lj_emit_arm64.h | 17 +++++++++++++----
+ 1 file changed, 13 insertions(+), 4 deletions(-)
+
+diff --git a/bundle/LuaJIT-2.1-20220411/src/lj_emit_arm64.h b/bundle/LuaJIT-2.1-20220411/src/lj_emit_arm64.h
+index d4c542557..9161c9582 100644
+--- a/bundle/LuaJIT-2.1-20220411/src/lj_emit_arm64.h
++++ b/bundle/LuaJIT-2.1-20220411/src/lj_emit_arm64.h
+@@ -113,6 +113,17 @@ static int emit_checkofs(A64Ins ai, int64_t ofs)
+   }
+ }
+ 
++static LJ_AINLINE uint32_t emit_lso_pair_candidate(A64Ins ai, int ofs, int sc)
++{
++  if (ofs >= 0) {
++    return ai | A64F_U12(ofs>>sc);  /* Subsequent lj_ror checks ofs. */
++  } else if (ofs >= -256) {
++    return (ai^A64I_LS_U) | A64F_S9(ofs & 0x1ff);
++  } else {
++    return A64F_D(31);  /* Will mismatch prev. */
++  }
++}
++
+ static void emit_lso(ASMState *as, A64Ins ai, Reg rd, Reg rn, int64_t ofs)
+ {
+   int ot = emit_checkofs(ai, ofs), sc = (ai >> 30) & 3;
+@@ -124,11 +135,9 @@ static void emit_lso(ASMState *as, A64Ins ai, Reg rd, Reg rn, int64_t ofs)
+     uint32_t prev = *as->mcp & ~A64F_D(31);
+     int ofsm = ofs - (1<<sc), ofsp = ofs + (1<<sc);
+     A64Ins aip;
+-    if (prev == (ai | A64F_N(rn) | A64F_U12(ofsm>>sc)) ||
+-	prev == ((ai^A64I_LS_U) | A64F_N(rn) | A64F_S9(ofsm&0x1ff))) {
++    if (prev == emit_lso_pair_candidate(ai | A64F_N(rn), ofsm, sc)) {
+       aip = (A64F_A(rd) | A64F_D(*as->mcp & 31));
+-    } else if (prev == (ai | A64F_N(rn) | A64F_U12(ofsp>>sc)) ||
+-	       prev == ((ai^A64I_LS_U) | A64F_N(rn) | A64F_S9(ofsp&0x1ff))) {
++    } else if (prev == emit_lso_pair_candidate(ai | A64F_N(rn), ofsp, sc)) {
+       aip = (A64F_D(rd) | A64F_A(*as->mcp & 31));
+       ofsm = ofs;
+     } else {