PPC: remove mov_label_addr and use GetLabelAddress instead

This is a followup CL to http://crrev.com/c/7807073.
GetLabelAddress can safely be used in isolate independent code
since it calculates the final address at runtime using LoadPC.

GetLabelAddress will later be optimized for >=P10.

IT: 10
Change-Id: Ic65cb2198d71b9b7feb421397ff0a7256feff5c3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/7832768
Reviewed-by: John <junyan1@ibm.com>
Commit-Queue: Milad Farazmand <mfarazma@ibm.com>
Cr-Commit-Position: refs/heads/main@{#107198}

src/baseline/ppc/baseline-assembler-ppc-inl.h

diff --git a/src/baseline/ppc/baseline-assembler-ppc-inl.h b/src/baseline/ppc/baseline-assembler-ppc-inl.h
index 9112d27..281e874 100644
--- a/src/baseline/ppc/baseline-assembler-ppc-inl.h
+++ b/src/baseline/ppc/baseline-assembler-ppc-inl.h
@@ -607,7 +607,8 @@
   // Ensure to emit the constant pool first if necessary.
   int entry_size_log2 = 3;
   __ ShiftLeftU32(reg, reg, Operand(entry_size_log2));
-  __ mov_label_addr(ip, &jump_table);
+  DCHECK_NE(reg, r0);
+  __ GetLabelAddress(ip, &jump_table, r0);
   __ AddS64(reg, reg, ip);
   __ Jump(reg);
   __ b(&fallthrough);

src/codegen/ppc/assembler-ppc.cc

diff --git a/src/codegen/ppc/assembler-ppc.cc b/src/codegen/ppc/assembler-ppc.cc
index 92e984d..d652db4 100644
--- a/src/codegen/ppc/assembler-ppc.cc
+++ b/src/codegen/ppc/assembler-ppc.cc
@@ -384,8 +384,7 @@
   kUnboundMovLabelOffsetOpcode = 0 << 26,
   kUnboundAddLabelOffsetOpcode = 1 << 26,
   kUnboundAddLabelLongOffsetOpcode = 2 << 26,
-  kUnboundMovLabelAddrOpcode = 3 << 26,
-  kUnboundJumpTableEntryOpcode = 4 << 26
+  kUnboundJumpTableEntryOpcode = 3 << 26
 };
 
 int Assembler::target_at(int pos) {
@@ -405,7 +404,6 @@
     case kUnboundMovLabelOffsetOpcode:
     case kUnboundAddLabelOffsetOpcode:
     case kUnboundAddLabelLongOffsetOpcode:
-    case kUnboundMovLabelAddrOpcode:
     case kUnboundJumpTableEntryOpcode:
       link = SIGN_EXT_IMM26(instr & kImm26Mask);
       link <<= 2;
@@ -482,16 +480,6 @@
       if (opcode == kUnboundAddLabelLongOffsetOpcode) patcher.nop();
       break;
     }
-    case kUnboundMovLabelAddrOpcode: {
-      // Load the address of the label in a register.
-      Register dst = Register::from_code(instr_at(pos + kInstrSize));
-      PatchingAssembler patcher(options(),
-                                reinterpret_cast<uint8_t*>(buffer_start_ + pos),
-                                kMovInstructionsNoConstantPool);
-      // Keep internal references relative until EmitRelocations.
-      patcher.bitwise_mov(dst, target_pos);
-      break;
-    }
     case kUnboundJumpTableEntryOpcode: {
       PatchingAssembler patcher(options(),
                                 reinterpret_cast<uint8_t*>(buffer_start_ + pos),
@@ -518,7 +506,6 @@
       return 16;
     case kUnboundMovLabelOffsetOpcode:
     case kUnboundAddLabelOffsetOpcode:
-    case kUnboundMovLabelAddrOpcode:
     case kUnboundJumpTableEntryOpcode:
       return 0;  // no limit on reach
   }
@@ -1504,35 +1491,6 @@
   }
 }
 
-void Assembler::mov_label_addr(Register dst, Label* label) {
-  CheckBuffer();
-  RecordRelocInfo(RelocInfo::INTERNAL_REFERENCE_ENCODED);
-  int position = link(label);
-  if (label->is_bound()) {
-    // Keep internal references relative until EmitRelocations.
-    bitwise_mov(dst, position);
-  } else {
-    // Encode internal reference to unbound label. We use a dummy opcode
-    // such that it won't collide with any opcode that might appear in the
-    // label's chain.  Encode the destination register in the 2nd instruction.
-    int link = position - pc_offset();
-    DCHECK_EQ(0, link & 3);
-    link >>= 2;
-    DCHECK(is_int26(link));
-
-    // When the label is bound, these instructions will be patched
-    // with a multi-instruction mov sequence that will load the
-    // destination register with the address of the label.
-    //
-    // target_at extracts the link and target_at_put patches the instructions.
-    BlockTrampolinePoolScope block_trampoline_pool(this);
-    emit(kUnboundMovLabelAddrOpcode | (link & kImm26Mask));
-    emit(dst.code());
-    DCHECK_GE(kMovInstructionsNoConstantPool, 2);
-    for (int i = 0; i < kMovInstructionsNoConstantPool - 2; i++) nop();
-  }
-}
-
 void Assembler::emit_label_addr(Label* label) {
   CheckBuffer();
   RecordRelocInfo(RelocInfo::INTERNAL_REFERENCE);

src/codegen/ppc/assembler-ppc.h

diff --git a/src/codegen/ppc/assembler-ppc.h b/src/codegen/ppc/assembler-ppc.h
index c59631a..00e5959 100644
--- a/src/codegen/ppc/assembler-ppc.h
+++ b/src/codegen/ppc/assembler-ppc.h
@@ -1058,10 +1058,6 @@
   void add_label_offset(Register dst, Register base, Label* label,
                         int delta = 0);
 
-  // Load the address of the label in a register and associate with an
-  // internal reference relocation.
-  void mov_label_addr(Register dst, Label* label);
-
   // Emit the address of the label (i.e. a jump table entry) and associate with
   // an internal reference relocation.
   void emit_label_addr(Label* label);

src/compiler/backend/ppc/code-generator-ppc.cc

diff --git a/src/compiler/backend/ppc/code-generator-ppc.cc b/src/compiler/backend/ppc/code-generator-ppc.cc
index 5c56d1d..c30d90c 100644
--- a/src/compiler/backend/ppc/code-generator-ppc.cc
+++ b/src/compiler/backend/ppc/code-generator-ppc.cc
@@ -3166,7 +3166,7 @@
   __ bge(GetLabel(i.InputRpo(1)));
   UseScratchRegisterScope temps(masm());
   Register scratch = temps.Acquire();
-  __ mov_label_addr(scratch, table);
+  __ GetLabelAddress(scratch, table, r0);
   __ ShiftLeftU64(r0, input, Operand(kSystemPointerSizeLog2));
   __ LoadU64(scratch, MemOperand(scratch, r0));
   __ Jump(scratch);