[mips][codegen] Remove PrepareForTailCall

Port: ec717160

Bug: v8:11879
Change-Id: Ib1ef3d984d559e4d4cec4d4daa9e1fec856f3686
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3058062
Auto-Submit: Liu yu <liuyu@loongson.cn>
Reviewed-by: Zhao Jiazhong <zhaojiazhong-hf@loongson.cn>
Commit-Queue: Zhao Jiazhong <zhaojiazhong-hf@loongson.cn>
Cr-Commit-Position: refs/heads/master@{#75971}

src/codegen/mips/macro-assembler-mips.cc

@@ -4296,52 +4296,6 @@ void TurboAssembler::MovToFloatParameters(DoubleRegister src1,
 // -----------------------------------------------------------------------------
 // JavaScript invokes.
 
-void TurboAssembler::PrepareForTailCall(Register callee_args_count,
-                                        Register caller_args_count,
-                                        Register scratch0, Register scratch1) {
-  // Calculate the end of destination area where we will put the arguments
-  // after we drop current frame. We add kPointerSize to count the receiver
-  // argument which is not included into formal parameters count.
-  Register dst_reg = scratch0;
-  Lsa(dst_reg, fp, caller_args_count, kPointerSizeLog2);
-  Addu(dst_reg, dst_reg,
-       Operand(StandardFrameConstants::kCallerSPOffset + kPointerSize));
-
-  Register src_reg = caller_args_count;
-  // Calculate the end of source area. +kPointerSize is for the receiver.
-  Lsa(src_reg, sp, callee_args_count, kPointerSizeLog2);
-  Addu(src_reg, src_reg, Operand(kPointerSize));
-
-  if (FLAG_debug_code) {
-    Check(lo, AbortReason::kStackAccessBelowStackPointer, src_reg,
-          Operand(dst_reg));
-  }
-
-  // Restore caller's frame pointer and return address now as they will be
-  // overwritten by the copying loop.
-  lw(ra, MemOperand(fp, StandardFrameConstants::kCallerPCOffset));
-  lw(fp, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
-
-  // Now copy callee arguments to the caller frame going backwards to avoid
-  // callee arguments corruption (source and destination areas could overlap).
-
-  // Both src_reg and dst_reg are pointing to the word after the one to copy,
-  // so they must be pre-decremented in the loop.
-  Register tmp_reg = scratch1;
-  Label loop, entry;
-  Branch(&entry);
-  bind(&loop);
-  Subu(src_reg, src_reg, Operand(kPointerSize));
-  Subu(dst_reg, dst_reg, Operand(kPointerSize));
-  lw(tmp_reg, MemOperand(src_reg));
-  sw(tmp_reg, MemOperand(dst_reg));
-  bind(&entry);
-  Branch(&loop, ne, sp, Operand(src_reg));
-
-  // Leave current frame.
-  mov(sp, dst_reg);
-}
-
 void MacroAssembler::LoadStackLimit(Register destination, StackLimitKind kind) {
   DCHECK(root_array_available());
   Isolate* isolate = this->isolate();

src/codegen/mips/macro-assembler-mips.h

@@ -460,15 +460,6 @@ class V8_EXPORT_PRIVATE TurboAssembler : public TurboAssemblerBase {
 
   void SmiUntag(Register dst, Register src) { sra(dst, src, kSmiTagSize); }
 
-  // Removes current frame and its arguments from the stack preserving
-  // the arguments and a return address pushed to the stack for the next call.
-  // Both |callee_args_count| and |caller_args_count| do not include
-  // receiver. |callee_args_count| is not modified. |caller_args_count|
-  // is trashed.
-  void PrepareForTailCall(Register callee_args_count,
-                          Register caller_args_count, Register scratch0,
-                          Register scratch1);
-
   int CalculateStackPassedWords(int num_reg_arguments,
                                 int num_double_arguments);
 

src/codegen/mips64/macro-assembler-mips64.cc

@@ -4818,52 +4818,6 @@ void TurboAssembler::MovToFloatParameters(DoubleRegister src1,
 // -----------------------------------------------------------------------------
 // JavaScript invokes.
 
-void TurboAssembler::PrepareForTailCall(Register callee_args_count,
-                                        Register caller_args_count,
-                                        Register scratch0, Register scratch1) {
-  // Calculate the end of destination area where we will put the arguments
-  // after we drop current frame. We add kPointerSize to count the receiver
-  // argument which is not included into formal parameters count.
-  Register dst_reg = scratch0;
-  Dlsa(dst_reg, fp, caller_args_count, kPointerSizeLog2);
-  Daddu(dst_reg, dst_reg,
-        Operand(StandardFrameConstants::kCallerSPOffset + kPointerSize));
-
-  Register src_reg = caller_args_count;
-  // Calculate the end of source area. +kPointerSize is for the receiver.
-  Dlsa(src_reg, sp, callee_args_count, kPointerSizeLog2);
-  Daddu(src_reg, src_reg, Operand(kPointerSize));
-
-  if (FLAG_debug_code) {
-    Check(lo, AbortReason::kStackAccessBelowStackPointer, src_reg,
-          Operand(dst_reg));
-  }
-
-  // Restore caller's frame pointer and return address now as they will be
-  // overwritten by the copying loop.
-  Ld(ra, MemOperand(fp, StandardFrameConstants::kCallerPCOffset));
-  Ld(fp, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
-
-  // Now copy callee arguments to the caller frame going backwards to avoid
-  // callee arguments corruption (source and destination areas could overlap).
-
-  // Both src_reg and dst_reg are pointing to the word after the one to copy,
-  // so they must be pre-decremented in the loop.
-  Register tmp_reg = scratch1;
-  Label loop, entry;
-  Branch(&entry);
-  bind(&loop);
-  Dsubu(src_reg, src_reg, Operand(kPointerSize));
-  Dsubu(dst_reg, dst_reg, Operand(kPointerSize));
-  Ld(tmp_reg, MemOperand(src_reg));
-  Sd(tmp_reg, MemOperand(dst_reg));
-  bind(&entry);
-  Branch(&loop, ne, sp, Operand(src_reg));
-
-  // Leave current frame.
-  mov(sp, dst_reg);
-}
-
 void MacroAssembler::LoadStackLimit(Register destination, StackLimitKind kind) {
   DCHECK(root_array_available());
   Isolate* isolate = this->isolate();

src/codegen/mips64/macro-assembler-mips64.h

@@ -485,15 +485,6 @@ class V8_EXPORT_PRIVATE TurboAssembler : public TurboAssemblerBase {
 
   void SmiUntag(Register reg) { SmiUntag(reg, reg); }
 
-  // Removes current frame and its arguments from the stack preserving
-  // the arguments and a return address pushed to the stack for the next call.
-  // Both |callee_args_count| and |caller_args_count| do not include
-  // receiver. |callee_args_count| is not modified. |caller_args_count|
-  // is trashed.
-  void PrepareForTailCall(Register callee_args_count,
-                          Register caller_args_count, Register scratch0,
-                          Register scratch1);
-
   int CalculateStackPassedWords(int num_reg_arguments,
                                 int num_double_arguments);