8380565: PPC64: deoptimization stub should save vector registers

8381315: compiler/vectorapi/TestVectorReallocation.java fails with -XX:UseAVX=1 after JDK-8380565

Reviewed-by: rrich
Backport-of: 7f4d121

Author: TheRealMDoerr

src/hotspot/cpu/ppc/registerMap_ppc.cpp

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2021, 2026, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2026 SAP SE. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+#include "runtime/registerMap.hpp"
+
+address RegisterMap::pd_location(VMReg base_reg, int slot_idx) const {
+  if (base_reg->is_VectorRegister()) {
+    // Not all physical slots belonging to a VectorRegister have corresponding
+    // valid VMReg locations in the RegisterMap.
+    // (See RegisterSaver::push_frame_reg_args_and_save_live_registers.)
+    // However, the slots are always saved to the stack in a contiguous region
+    // of memory so we can calculate the address of the upper slots by
+    // offsetting from the base address.
+    assert(base_reg->is_concrete(), "must pass base reg");
+    address base_location = location(base_reg, nullptr);
+    if (base_location != nullptr) {
+      intptr_t offset_in_bytes = slot_idx * VMRegImpl::stack_slot_size;
+      return base_location + offset_in_bytes;
+    } else {
+      return nullptr;
+    }
+  } else {
+    return location(base_reg->next(slot_idx), nullptr);
+  }
+}

src/hotspot/cpu/ppc/registerMap_ppc.hpp

@@ -1,6 +1,6 @@
 /*
- * Copyright (c) 2000, 2023, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2012, 2013 SAP SE. All rights reserved.
+ * Copyright (c) 2000, 2026, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2026 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,9 +35,7 @@
   // Since there is none, we just return null.
   address pd_location(VMReg reg) const { return nullptr; }
 
-  address pd_location(VMReg base_reg, int slot_idx) const {
-    return location(base_reg->next(slot_idx), nullptr);
-  }
+  address pd_location(VMReg base_reg, int slot_idx) const;
 
   // no PD state to clear or copy:
   void pd_clear() {}

src/hotspot/cpu/ppc/sharedRuntime_ppc.cpp

@@ -103,7 +103,7 @@ class RegisterSaver {
 
   // During deoptimization only the result registers need to be restored
   // all the other values have already been extracted.
-  static void restore_result_registers(MacroAssembler* masm, int frame_size_in_bytes);
+  static void restore_result_registers(MacroAssembler* masm, int frame_size_in_bytes, bool save_vectors);
 
   // Constants and data structures:
 
@@ -355,7 +355,7 @@ OopMap* RegisterSaver::push_frame_reg_args_and_save_live_registers(MacroAssemble
   }
 
   // Note that generate_oop_map in the following loop is only used for the
-  // polling_page_vectors_safepoint_handler_blob.
+  // polling_page_vectors_safepoint_handler_blob and the deopt_blob.
   // The order in which the vector contents are stored depends on Endianess and
   // the utilized instructions (PowerArchitecturePPC64).
   assert(is_aligned(offset, StackAlignmentInBytes), "should be");
@@ -367,6 +367,7 @@ OopMap* RegisterSaver::push_frame_reg_args_and_save_live_registers(MacroAssemble
 
       __ stxvp(as_VectorRegister(reg_num).to_vsr(), offset, R1_SP);
       // Note: The contents were read in the same order (see loadV16_Power9 node in ppc.ad).
+      // RegisterMap::pd_location only uses the first VMReg for each VectorRegister.
       if (generate_oop_map) {
         map->set_callee_saved(VMRegImpl::stack2reg(offset >> 2),
                               RegisterSaver_LiveVecRegs[i LITTLE_ENDIAN_ONLY(+1) ].vmreg);
@@ -386,6 +387,7 @@ OopMap* RegisterSaver::push_frame_reg_args_and_save_live_registers(MacroAssemble
         __ stxvd2x(as_VectorRegister(reg_num)->to_vsr(), R31, R1_SP);
       }
       // Note: The contents were read in the same order (see loadV16_Power8 / loadV16_Power9 node in ppc.ad).
+      // RegisterMap::pd_location only uses the first VMReg for each VectorRegister.
       if (generate_oop_map) {
         VMReg vsr = RegisterSaver_LiveVecRegs[i].vmreg;
         map->set_callee_saved(VMRegImpl::stack2reg(offset >> 2), vsr);
@@ -572,10 +574,14 @@ void RegisterSaver::restore_argument_registers_and_pop_frame(MacroAssembler*masm
 }
 
 // Restore the registers that might be holding a result.
-void RegisterSaver::restore_result_registers(MacroAssembler* masm, int frame_size_in_bytes) {
+void RegisterSaver::restore_result_registers(MacroAssembler* masm, int frame_size_in_bytes, bool save_vectors) {
   const int regstosave_num       = sizeof(RegisterSaver_LiveRegs) /
                                    sizeof(RegisterSaver::LiveRegType);
-  const int register_save_size   = regstosave_num * reg_size; // VS registers not relevant here.
+  const int vecregstosave_num    = save_vectors ? (sizeof(RegisterSaver_LiveVecRegs) /
+                                                   sizeof(RegisterSaver::LiveRegType))
+                                                : 0;
+  const int register_save_size   = regstosave_num * reg_size + vecregstosave_num * vec_reg_size;
+
   const int register_save_offset = frame_size_in_bytes - register_save_size;
 
   // restore all result registers (ints and floats)
@@ -604,7 +610,7 @@ void RegisterSaver::restore_result_registers(MacroAssembler* masm, int frame_siz
     offset += reg_size;
   }
 
-  assert(offset == frame_size_in_bytes, "consistency check");
+  assert(offset == frame_size_in_bytes - (save_vectors ? vecregstosave_num * vec_reg_size : 0), "consistency check");
 }
 
 // Is vector's size (in bytes) bigger than a size saved by default?
@@ -2993,7 +2999,8 @@ void SharedRuntime::generate_deopt_blob() {
                                                                    &first_frame_size_in_bytes,
                                                                    /*generate_oop_map=*/ true,
                                                                    return_pc_adjustment_no_exception,
-                                                                   RegisterSaver::return_pc_is_lr);
+                                                                   RegisterSaver::return_pc_is_lr,
+                                                                   /*save_vectors*/ SuperwordUseVSX);
   assert(map != nullptr, "OopMap must have been created");
 
   __ li(exec_mode_reg, Deoptimization::Unpack_deopt);
@@ -3028,7 +3035,8 @@ void SharedRuntime::generate_deopt_blob() {
                                                              &first_frame_size_in_bytes,
                                                              /*generate_oop_map=*/ false,
                                                              /*return_pc_adjustment_exception=*/ 0,
-                                                             RegisterSaver::return_pc_is_pre_saved);
+                                                             RegisterSaver::return_pc_is_pre_saved,
+                                                             /*save_vectors*/ SuperwordUseVSX);
 
   // Deopt during an exception. Save exec mode for unpack_frames.
   __ li(exec_mode_reg, Deoptimization::Unpack_exception);
@@ -3046,7 +3054,8 @@ void SharedRuntime::generate_deopt_blob() {
                                                              &first_frame_size_in_bytes,
                                                              /*generate_oop_map=*/ false,
                                                              /*return_pc_adjustment_reexecute=*/ 0,
-                                                             RegisterSaver::return_pc_is_pre_saved);
+                                                             RegisterSaver::return_pc_is_pre_saved,
+                                                             /*save_vectors*/ SuperwordUseVSX);
   __ li(exec_mode_reg, Deoptimization::Unpack_reexecute);
 #endif
 
@@ -3072,7 +3081,7 @@ void SharedRuntime::generate_deopt_blob() {
 
   // Restore only the result registers that have been saved
   // by save_volatile_registers(...).
-  RegisterSaver::restore_result_registers(masm, first_frame_size_in_bytes);
+  RegisterSaver::restore_result_registers(masm, first_frame_size_in_bytes, /*save_vectors*/ SuperwordUseVSX);
 
   // reload the exec mode from the UnrollBlock (it might have changed)
   __ lwz(exec_mode_reg, in_bytes(Deoptimization::UnrollBlock::unpack_kind_offset()), unroll_block_reg);

src/hotspot/cpu/ppc/vm_version_ppc.cpp

@@ -25,6 +25,7 @@
 
 #include "asm/assembler.inline.hpp"
 #include "asm/macroAssembler.inline.hpp"
+#include "compiler/compilerDefinitions.inline.hpp"
 #include "compiler/disassembler.hpp"
 #include "jvm.h"
 #include "memory/resourceArea.hpp"
@@ -103,7 +104,7 @@ void VM_Version::initialize() {
 
   if (PowerArchitecturePPC64 >= 9) {
     // Performance is good since Power9.
-    if (FLAG_IS_DEFAULT(SuperwordUseVSX)) {
+    if (FLAG_IS_DEFAULT(SuperwordUseVSX) && CompilerConfig::is_c2_enabled()) {
       FLAG_SET_ERGO(SuperwordUseVSX, true);
     }
   }