File 1121-AArch64-Slightly-optimize-BIF-dispatch.patch of Package erlang

From 0de80a567f493807c0b1130a0e08199d0706123b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Sat, 26 Aug 2023 08:38:40 +0200
Subject: [PATCH 01/25] AArch64: Slightly optimize BIF dispatch

No BIFs have more than four arguments, so there is no need to
save and restore {x,4} and {x,5}.
---
 erts/emulator/beam/emu/beam_emu.c        |  2 ++
 erts/emulator/beam/erl_vm.h              |  2 ++
 erts/emulator/beam/jit/arm/instr_bif.cpp | 11 ++++++-----
 erts/emulator/beam/jit/beam_jit_main.cpp |  2 ++
 4 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/erts/emulator/beam/emu/beam_emu.c b/erts/emulator/beam/emu/beam_emu.c
index c2081ab3d0..bdc0173bed 100644
--- a/erts/emulator/beam/emu/beam_emu.c
+++ b/erts/emulator/beam/emu/beam_emu.c
@@ -631,6 +631,8 @@ static void install_bifs(void) {
 
         entry = &bif_table[i];
 
+        ERTS_ASSERT(entry->arity <= MAX_BIF_ARITY);
+
         ep = erts_export_put(entry->module, entry->name, entry->arity);
 
         ep->info.u.op = BeamOpCodeAddr(op_i_func_info_IaaI);
diff --git a/erts/emulator/beam/erl_vm.h b/erts/emulator/beam/erl_vm.h
index faf6190e39..a7b4b86516 100644
--- a/erts/emulator/beam/erl_vm.h
+++ b/erts/emulator/beam/erl_vm.h
@@ -53,6 +53,8 @@
 #define MAX_REG      1024            /* Max number of x(N) registers used */
 #define REG_MASK     (MAX_REG - 1)
 
+#define MAX_BIF_ARITY 4 /* Maximum allowed arguments for C-based BIFs. */
+
 /*
  * Guard BIFs and the new trapping length/1 implementation need 3 extra
  * registers in the register array.
diff --git a/erts/emulator/beam/jit/arm/instr_bif.cpp b/erts/emulator/beam/jit/arm/instr_bif.cpp
index b210bfada9..ca6db3e6e8 100644
--- a/erts/emulator/beam/jit/arm/instr_bif.cpp
+++ b/erts/emulator/beam/jit/arm/instr_bif.cpp
@@ -387,7 +387,7 @@ void BeamGlobalAssembler::emit_call_light_bif_shared() {
 
         emit_enter_runtime_frame();
         emit_enter_runtime<Update::eReductions | Update::eStack |
-                           Update::eHeap | Update::eXRegs>();
+                           Update::eHeap | Update::eXRegs>(MAX_BIF_ARITY);
 
 #ifdef ERTS_MSACC_EXTENDED_STATES
         {
@@ -460,7 +460,8 @@ void BeamGlobalAssembler::emit_call_light_bif_shared() {
          * after seeing a later timestamp from its own call to
          * erlang:monotonic_time/0. */
         emit_leave_runtime<Update::eReductions | Update::eCodeIndex |
-                           Update::eHeap | Update::eStack | Update::eXRegs>();
+                           Update::eHeap | Update::eStack | Update::eXRegs>(
+                MAX_BIF_ARITY);
         emit_leave_runtime_frame();
 
         /* ERTS_IS_GC_DESIRED_INTERNAL */
@@ -528,7 +529,7 @@ void BeamGlobalAssembler::emit_call_light_bif_shared() {
         {
             emit_enter_runtime_frame();
             emit_enter_runtime<Update::eReductions | Update::eStack |
-                               Update::eHeap | Update::eXRegs>();
+                               Update::eHeap | Update::eXRegs>(MAX_BIF_ARITY);
 
             a.mov(ARG3, ARG1);
 
@@ -540,7 +541,7 @@ void BeamGlobalAssembler::emit_call_light_bif_shared() {
             runtime_call<5>(erts_gc_after_bif_call_lhf);
 
             emit_leave_runtime<Update::eReductions | Update::eStack |
-                               Update::eHeap | Update::eXRegs>();
+                               Update::eHeap | Update::eXRegs>(MAX_BIF_ARITY);
             emit_leave_runtime_frame();
 
             a.b(check_bif_return);
@@ -568,6 +569,7 @@ void BeamGlobalAssembler::emit_call_light_bif_shared() {
 void BeamModuleAssembler::emit_call_light_bif(const ArgWord &Bif,
                                               const ArgExport &Exp) {
     Label entry = a.newLabel();
+    BeamFile_ImportEntry *e = &beam->imports.entries[Exp.get()];
 
     a.bind(entry);
 
@@ -576,7 +578,6 @@ void BeamModuleAssembler::emit_call_light_bif(const ArgWord &Bif,
     a.adr(ARG3, entry);
 
     if (logger.file()) {
-        BeamFile_ImportEntry *e = &beam->imports.entries[Exp.get()];
         comment("BIF: %T:%T/%d", e->module, e->function, e->arity);
     }
     fragment_call(ga->get_call_light_bif_shared());
diff --git a/erts/emulator/beam/jit/beam_jit_main.cpp b/erts/emulator/beam/jit/beam_jit_main.cpp
index 7692e4b2d9..40679e8be5 100644
--- a/erts/emulator/beam/jit/beam_jit_main.cpp
+++ b/erts/emulator/beam/jit/beam_jit_main.cpp
@@ -124,6 +124,8 @@ static void install_bifs(void) {
 
         entry = &bif_table[i];
 
+        ERTS_ASSERT(entry->arity <= MAX_BIF_ARITY);
+
         ep = erts_export_put(entry->module, entry->name, entry->arity);
 
         sys_memset(&ep->info.u, 0, sizeof(ep->info.u));
-- 
2.35.3