From 189fc8ddeffb4dd595ccd8ad3ca53a0ed4cee91f Mon Sep 17 00:00:00 2001
From: Amit Kumar <amitkumar@openjdk.org>
Date: Wed, 20 Nov 2024 08:25:37 +0000
Subject: [PATCH] 8344381: [s390x] Test failures with error: Register type is
 not known

Reviewed-by: mdoerr, lucy
---
 .../gc/shared/barrierSetAssembler_s390.cpp    | 34 ++++++++++++++-----
 1 file changed, 26 insertions(+), 8 deletions(-)

diff --git a/src/hotspot/cpu/s390/gc/shared/barrierSetAssembler_s390.cpp b/src/hotspot/cpu/s390/gc/shared/barrierSetAssembler_s390.cpp
index d826b4a06f3..8ead8e8ff38 100644
--- a/src/hotspot/cpu/s390/gc/shared/barrierSetAssembler_s390.cpp
+++ b/src/hotspot/cpu/s390/gc/shared/barrierSetAssembler_s390.cpp
@@ -218,10 +218,10 @@ SaveLiveRegisters::SaveLiveRegisters(MacroAssembler *masm, BarrierStubC2 *stub)
 
   const int register_save_size = iterate_over_register_mask(ACTION_COUNT_ONLY) * BytesPerWord;
 
-  _frame_size = align_up(register_save_size, frame::alignment_in_bytes) + frame::z_abi_160_size; // FIXME: this could be restricted to argument only
+  _frame_size = align_up(register_save_size, frame::alignment_in_bytes) + frame::z_abi_160_size;
 
   __ save_return_pc();
-  __ push_frame(_frame_size, Z_R14); // FIXME: check if Z_R1_scaratch can do a job here;
+  __ push_frame(_frame_size, Z_R14);
 
   __ z_lg(Z_R14, _z_common_abi(return_pc) + _frame_size, Z_SP);
 
@@ -240,6 +240,7 @@ int SaveLiveRegisters::iterate_over_register_mask(IterationAction action, int of
   int reg_save_index = 0;
   RegMaskIterator live_regs_iterator(_reg_mask);
 
+  // Going to preserve the volatile registers which can be used by Register Allocator.
   while(live_regs_iterator.has_next()) {
     const OptoReg::Name opto_reg = live_regs_iterator.next();
 
@@ -251,8 +252,11 @@ int SaveLiveRegisters::iterate_over_register_mask(IterationAction action, int of
     const VMReg vm_reg = OptoReg::as_VMReg(opto_reg);
     if (vm_reg->is_Register()) {
       Register std_reg = vm_reg->as_Register();
-
-      if (std_reg->encoding() >= Z_R2->encoding() && std_reg->encoding() <= Z_R15->encoding()) {
+      // Z_R0 and Z_R1 will not be allocated by the register allocator, see s390.ad (Integer Register Classes)
+      // Z_R6 to Z_R15 are saved registers, except Z_R14 (see Z-Abi)
+      if (std_reg->encoding() == Z_R14->encoding() ||
+         (std_reg->encoding() >= Z_R2->encoding()  &&
+          std_reg->encoding() <= Z_R5->encoding())) {
         reg_save_index++;
 
         if (action == ACTION_SAVE) {
@@ -265,8 +269,10 @@ int SaveLiveRegisters::iterate_over_register_mask(IterationAction action, int of
       }
     } else if (vm_reg->is_FloatRegister()) {
       FloatRegister fp_reg = vm_reg->as_FloatRegister();
-      if (fp_reg->encoding() >= Z_F0->encoding() && fp_reg->encoding() <= Z_F15->encoding()
-          && fp_reg->encoding() != Z_F1->encoding()) {
+      // Z_R1 will not be allocated by the register allocator, see s390.ad (Float Register Classes)
+      if (fp_reg->encoding() >= Z_F0->encoding() &&
+          fp_reg->encoding() <= Z_F7->encoding() &&
+          fp_reg->encoding() != Z_F1->encoding()) {
         reg_save_index++;
 
         if (action == ACTION_SAVE) {
@@ -277,8 +283,20 @@ int SaveLiveRegisters::iterate_over_register_mask(IterationAction action, int of
           assert(action == ACTION_COUNT_ONLY, "Sanity");
         }
       }
-    } else if (false /* vm_reg->is_VectorRegister() */){
-      fatal("Vector register support is not there yet!");
+    } else if (vm_reg->is_VectorRegister()) {
+      VectorRegister vs_reg = vm_reg->as_VectorRegister();
+      // Z_V0 to Z_V15 will not be allocated by the register allocator, see s390.ad (reg class z_v_reg)
+      if (vs_reg->encoding() >= Z_V16->encoding() &&
+          vs_reg->encoding() <= Z_V31->encoding()) {
+        reg_save_index += 2;
+        if (action == ACTION_SAVE) {
+          __ z_vst(vs_reg, Address(Z_SP, offset - reg_save_index * BytesPerWord));
+        } else if (action == ACTION_RESTORE) {
+          __ z_vl(vs_reg, Address(Z_SP, offset - reg_save_index * BytesPerWord));
+        } else {
+          assert(action == ACTION_COUNT_ONLY, "Sanity");
+        }
+      }
     } else {
       fatal("Register type is not known");
     }