s390: [liftoff] Fix jump table patching

Change-Id: I18181e0328353e14f9f5793779db4806b759ac9b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3212293
Reviewed-by: Joran Siu <joransiu@ca.ibm.com>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Junliang Yan <junyan@redhat.com>
Cr-Commit-Position: refs/heads/main@{#77310}

src/codegen/s390/assembler-s390.cc

@@ -483,10 +483,10 @@ int Assembler::target_at(int pos) {
     if (imm16 == 0) return kEndOfChain;
     return pos + imm16;
   } else if (LLILF == opcode || BRCL == opcode || LARL == opcode ||
-             BRASL == opcode) {
+             BRASL == opcode || LGRL == opcode) {
     int32_t imm32 =
         static_cast<int32_t>(instr & (static_cast<uint64_t>(0xFFFFFFFF)));
-    if (LLILF != opcode)
+    if (LLILF != opcode && LGRL != opcode)
       imm32 <<= 1;  // BR* + LARL treat immediate in # of halfwords
     if (imm32 == 0) return kEndOfChain;
     return pos + imm32;
@@ -527,6 +527,12 @@ void Assembler::target_at_put(int pos, int target_pos, bool* is_branch) {
     instr &= (~static_cast<uint64_t>(0xFFFFFFFF));
     instr_at_put<SixByteInstr>(pos, instr | (imm32 >> 1));
     return;
+  } else if (LGRL == opcode) {
+    // Immediate is in # of bytes
+    int32_t imm32 = target_pos - pos;
+    instr &= (~static_cast<uint64_t>(0xFFFFFFFF));
+    instr_at_put<SixByteInstr>(pos, instr | imm32);
+    return;
   } else if (LLILF == opcode) {
     DCHECK(target_pos == kEndOfChain || target_pos >= 0);
     // Emitted label constant, not part of a branch.
@@ -557,7 +563,7 @@ int Assembler::max_reach_from(int pos) {
       BRXHG == opcode) {
     return 16;
   } else if (LLILF == opcode || BRCL == opcode || LARL == opcode ||
-             BRASL == opcode) {
+             BRASL == opcode || LGRL == opcode) {
     return 31;  // Using 31 as workaround instead of 32 as
                 // is_intn(x,32) doesn't work on 32-bit platforms.
                 // llilf: Emitted label constant, not part of
@@ -699,6 +705,10 @@ void Assembler::larl(Register r1, Label* l) {
   larl(r1, Operand(branch_offset(l)));
 }
 
+void Assembler::lgrl(Register r1, Label* l) {
+  lgrl(r1, Operand(branch_offset(l)));
+}
+
 void Assembler::EnsureSpaceFor(int space_needed) {
   if (buffer_space() <= (kGap + space_needed)) {
     GrowBuffer(space_needed);

src/codegen/s390/assembler-s390.h

@@ -1281,6 +1281,7 @@ class V8_EXPORT_PRIVATE Assembler : public AssemblerBase {
 
   // Load Address Instructions
   void larl(Register r, Label* l);
+  void lgrl(Register r, Label* l);
 
   // Exception-generating instructions and debugging support
   void stop(Condition cond = al, int32_t code = kDefaultStopCode,

src/execution/s390/simulator-s390.cc

@@ -6713,9 +6713,12 @@ EVALUATE(STHRL) {
 }
 
 EVALUATE(LGRL) {
-  UNIMPLEMENTED();
-  USE(instr);
-  return 0;
+  DCHECK_OPCODE(LGRL);
+  DECODE_RIL_B_INSTRUCTION(r1, i2);
+  intptr_t offset = i2;
+  int64_t mem_val = ReadDW(get_pc() + offset);
+  set_register(r1, mem_val);
+  return length;
 }
 
 EVALUATE(STGRL) {

src/wasm/jump-table-assembler.cc

@@ -211,18 +211,32 @@ void JumpTableAssembler::EmitLazyCompileJumpSlot(uint32_t func_index,
 }
 
 bool JumpTableAssembler::EmitJumpSlot(Address target) {
-  mov(r1, Operand(target, RelocInfo::CODE_TARGET));
-  b(r1);
+  intptr_t relative_target = reinterpret_cast<byte*>(target) - pc_;
+
+  if (!is_int32(relative_target / 2)) {
+    return false;
+  }
+
+  brcl(al, Operand(relative_target / 2));
+  nop(0);  // make the slot align to 8 bytes
   return true;
 }
 
 void JumpTableAssembler::EmitFarJumpSlot(Address target) {
-  JumpToInstructionStream(target);
+  Label target_addr;
+  lgrl(ip, &target_addr);  // 6 bytes
+  b(ip);                   // 8 bytes
+
+  CHECK_EQ(reinterpret_cast<Address>(pc_) & 0x7, 0);  // Alignment
+  bind(&target_addr);
+  dp(target);
 }
 
 // static
 void JumpTableAssembler::PatchFarJumpSlot(Address slot, Address target) {
-  UNREACHABLE();
+  Address target_addr = slot + 8;
+  reinterpret_cast<std::atomic<Address>*>(target_addr)
+      ->store(target, std::memory_order_relaxed);
 }
 
 void JumpTableAssembler::NopBytes(int bytes) {

src/wasm/jump-table-assembler.h

@@ -201,8 +201,8 @@ class V8_EXPORT_PRIVATE JumpTableAssembler : public MacroAssembler {
   static constexpr int kLazyCompileTableSlotSize = 3 * kInstrSize;
 #elif V8_TARGET_ARCH_S390X
   static constexpr int kJumpTableLineSize = 128;
-  static constexpr int kJumpTableSlotSize = 14;
-  static constexpr int kFarJumpTableSlotSize = 14;
+  static constexpr int kJumpTableSlotSize = 8;
+  static constexpr int kFarJumpTableSlotSize = 16;
   static constexpr int kLazyCompileTableSlotSize = 20;
 #elif V8_TARGET_ARCH_PPC64
   static constexpr int kJumpTableLineSize = 64;