[codegen] Removed ParameterCount class

It was used only with Register inputs, so we can replace its uses with
the Registers themselves.

Change-Id: I1ea3ed88ee41177b696a7281cdf3b90fefdc5870
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1886916Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64639}

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

@@ -1494,35 +1494,23 @@ void TurboAssembler::MovFromFloatParameter(DwVfpRegister dst) {
   MovFromFloatResult(dst);
 }
 
-void TurboAssembler::PrepareForTailCall(const ParameterCount& callee_args_count,
-                                        Register caller_args_count_reg,
+void TurboAssembler::PrepareForTailCall(Register callee_args_count,
+                                        Register caller_args_count,
                                         Register scratch0, Register scratch1) {
-#if DEBUG
-  if (callee_args_count.is_reg()) {
-    DCHECK(!AreAliased(callee_args_count.reg(), caller_args_count_reg, scratch0,
-                       scratch1));
-  } else {
-    DCHECK(!AreAliased(caller_args_count_reg, scratch0, scratch1));
-  }
-#endif
+  DCHECK(!AreAliased(callee_args_count, caller_args_count, scratch0, 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;
-  add(dst_reg, fp, Operand(caller_args_count_reg, LSL, kPointerSizeLog2));
+  add(dst_reg, fp, Operand(caller_args_count, LSL, kPointerSizeLog2));
   add(dst_reg, dst_reg,
       Operand(StandardFrameConstants::kCallerSPOffset + kPointerSize));
 
-  Register src_reg = caller_args_count_reg;
+  Register src_reg = caller_args_count;
   // Calculate the end of source area. +kPointerSize is for the receiver.
-  if (callee_args_count.is_reg()) {
-    add(src_reg, sp, Operand(callee_args_count.reg(), LSL, kPointerSizeLog2));
-    add(src_reg, src_reg, Operand(kPointerSize));
-  } else {
-    add(src_reg, sp,
-        Operand((callee_args_count.immediate() + 1) * kPointerSize));
-  }
+  add(src_reg, sp, Operand(callee_args_count, LSL, kPointerSizeLog2));
+  add(src_reg, src_reg, Operand(kPointerSize));
 
   if (FLAG_debug_code) {
     cmp(src_reg, dst_reg);

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

@@ -223,11 +223,11 @@ class V8_EXPORT_PRIVATE TurboAssembler : public TurboAssemblerBase {
 
   // 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_reg| do not include
-  // receiver. |callee_args_count| is not modified, |caller_args_count_reg|
+  // 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(const ParameterCount& callee_args_count,
-                          Register caller_args_count_reg, Register scratch0,
+  void PrepareForTailCall(Register callee_args_count,
+                          Register caller_args_count, Register scratch0,
                           Register scratch1);
 
   // There are two ways of passing double arguments on ARM, depending on

src/codegen/arm64/macro-assembler-arm64.cc

@@ -2074,23 +2074,16 @@ void TurboAssembler::CallForDeoptimization(Address target, int deopt_id) {
   DCHECK_EQ(SizeOfCodeGeneratedSince(&start), Deoptimizer::kDeoptExitSize);
 }
 
-void TurboAssembler::PrepareForTailCall(const ParameterCount& callee_args_count,
-                                        Register caller_args_count_reg,
+void TurboAssembler::PrepareForTailCall(Register callee_args_count,
+                                        Register caller_args_count,
                                         Register scratch0, Register scratch1) {
-#if DEBUG
-  if (callee_args_count.is_reg()) {
-    DCHECK(!AreAliased(callee_args_count.reg(), caller_args_count_reg, scratch0,
-                       scratch1));
-  } else {
-    DCHECK(!AreAliased(caller_args_count_reg, scratch0, scratch1));
-  }
-#endif
+  DCHECK(!AreAliased(callee_args_count, caller_args_count, scratch0, scratch1));
 
   // Calculate the end of destination area where we will put the arguments
   // after we drop current frame. We add kSystemPointerSize to count the
   // receiver argument which is not included into formal parameters count.
   Register dst_reg = scratch0;
-  Add(dst_reg, fp, Operand(caller_args_count_reg, LSL, kSystemPointerSizeLog2));
+  Add(dst_reg, fp, Operand(caller_args_count, LSL, kSystemPointerSizeLog2));
   Add(dst_reg, dst_reg,
       StandardFrameConstants::kCallerSPOffset + kSystemPointerSize);
   // Round dst_reg up to a multiple of 16 bytes, so that we overwrite any
@@ -2098,15 +2091,10 @@ void TurboAssembler::PrepareForTailCall(const ParameterCount& callee_args_count,
   Add(dst_reg, dst_reg, 15);
   Bic(dst_reg, dst_reg, 15);
 
-  Register src_reg = caller_args_count_reg;
+  Register src_reg = caller_args_count;
   // Calculate the end of source area. +kSystemPointerSize is for the receiver.
-  if (callee_args_count.is_reg()) {
-    Add(src_reg, sp,
-        Operand(callee_args_count.reg(), LSL, kSystemPointerSizeLog2));
-    Add(src_reg, src_reg, kSystemPointerSize);
-  } else {
-    Add(src_reg, sp, (callee_args_count.immediate() + 1) * kSystemPointerSize);
-  }
+  Add(src_reg, sp, Operand(callee_args_count, LSL, kSystemPointerSizeLog2));
+  Add(src_reg, src_reg, kSystemPointerSize);
 
   // Round src_reg up to a multiple of 16 bytes, so we include any potential
   // padding in the copy.

src/codegen/arm64/macro-assembler-arm64.h

@@ -566,11 +566,11 @@ class V8_EXPORT_PRIVATE TurboAssembler : public TurboAssemblerBase {
 
   // 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_reg| do not include
-  // receiver. |callee_args_count| is not modified, |caller_args_count_reg|
-  // is trashed.
-  void PrepareForTailCall(const ParameterCount& callee_args_count,
-                          Register caller_args_count_reg, Register scratch0,
+  // 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);
 
   inline void SmiUntag(Register dst, Register src);

src/codegen/ia32/macro-assembler-ia32.cc

@@ -1028,36 +1028,18 @@ void MacroAssembler::JumpToInstructionStream(Address entry) {
 }
 
 void TurboAssembler::PrepareForTailCall(
-    const ParameterCount& callee_args_count, Register caller_args_count_reg,
-    Register scratch0, Register scratch1,
-    int number_of_temp_values_after_return_address) {
-#if DEBUG
-  if (callee_args_count.is_reg()) {
-    DCHECK(!AreAliased(callee_args_count.reg(), caller_args_count_reg, scratch0,
-                       scratch1));
-  } else {
-    DCHECK(!AreAliased(caller_args_count_reg, scratch0, scratch1));
-  }
-#endif
+    Register callee_args_count, Register caller_args_count, Register scratch0,
+    Register scratch1, int number_of_temp_values_after_return_address) {
+  DCHECK(!AreAliased(callee_args_count, caller_args_count, scratch0, scratch1));
 
   // Calculate the destination address where we will put the return address
   // after we drop current frame.
   Register new_sp_reg = scratch0;
-  if (callee_args_count.is_reg()) {
-    sub(caller_args_count_reg, callee_args_count.reg());
-    lea(new_sp_reg,
-        Operand(ebp, caller_args_count_reg, times_system_pointer_size,
-                StandardFrameConstants::kCallerPCOffset -
-                    number_of_temp_values_after_return_address *
-                        kSystemPointerSize));
-  } else {
-    lea(new_sp_reg,
-        Operand(ebp, caller_args_count_reg, times_system_pointer_size,
-                StandardFrameConstants::kCallerPCOffset -
-                    (callee_args_count.immediate() +
-                     number_of_temp_values_after_return_address) *
-                        kSystemPointerSize));
-  }
+  sub(caller_args_count, callee_args_count);
+  lea(new_sp_reg, Operand(ebp, caller_args_count, times_system_pointer_size,
+                          StandardFrameConstants::kCallerPCOffset -
+                              number_of_temp_values_after_return_address *
+                                  kSystemPointerSize));
 
   if (FLAG_debug_code) {
     cmp(esp, new_sp_reg);
@@ -1078,15 +1060,9 @@ void TurboAssembler::PrepareForTailCall(
   mov(ebp, Operand(ebp, StandardFrameConstants::kCallerFPOffset));
 
   // +2 here is to copy both receiver and return address.
-  Register count_reg = caller_args_count_reg;
-  if (callee_args_count.is_reg()) {
-    lea(count_reg, Operand(callee_args_count.reg(),
-                           2 + number_of_temp_values_after_return_address));
-  } else {
-    mov(count_reg, Immediate(callee_args_count.immediate() + 2 +
-                             number_of_temp_values_after_return_address));
-    // TODO(ishell): Unroll copying loop for small immediate values.
-  }
+  Register count_reg = caller_args_count;
+  lea(count_reg, Operand(callee_args_count,
+                         2 + number_of_temp_values_after_return_address));
 
   // Now copy callee arguments to the caller frame going backwards to avoid
   // callee arguments corruption (source and destination areas could overlap).

src/codegen/ia32/macro-assembler-ia32.h

@@ -140,14 +140,14 @@ class V8_EXPORT_PRIVATE TurboAssembler : public TurboAssemblerBase {
 
   // 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_reg| do not include receiver.
-  // |callee_args_count| is not modified, |caller_args_count_reg| is trashed.
+  // |callee_args_count| and |caller_args_count| do not include receiver.
+  // |callee_args_count| is not modified. |caller_args_count| is trashed.
   // |number_of_temp_values_after_return_address| specifies the number of words
   // pushed to the stack after the return address. This is to allow "allocation"
   // of scratch registers that this function requires by saving their values on
   // the stack.
-  void PrepareForTailCall(const ParameterCount& callee_args_count,
-                          Register caller_args_count_reg, Register scratch0,
+  void PrepareForTailCall(Register callee_args_count,
+                          Register caller_args_count, Register scratch0,
                           Register scratch1,
                           int number_of_temp_values_after_return_address);
 

src/codegen/macro-assembler.h

@@ -186,34 +186,6 @@ class NoRootArrayScope {
   bool old_value_;
 };
 
-// Wrapper class for passing expected and actual parameter counts as
-// either registers or immediate values. Used to make sure that the
-// caller provides exactly the expected number of parameters to the
-// callee.
-class ParameterCount {
- public:
-  explicit ParameterCount(Register reg) : reg_(reg), immediate_(0) {}
-  explicit ParameterCount(uint16_t imm) : reg_(no_reg), immediate_(imm) {}
-
-  bool is_reg() const { return reg_.is_valid(); }
-  bool is_immediate() const { return !is_reg(); }
-
-  Register reg() const {
-    DCHECK(is_reg());
-    return reg_;
-  }
-  uint16_t immediate() const {
-    DCHECK(is_immediate());
-    return immediate_;
-  }
-
- private:
-  const Register reg_;
-  const uint16_t immediate_;
-
-  DISALLOW_IMPLICIT_CONSTRUCTORS(ParameterCount);
-};
-
 }  // namespace internal
 }  // namespace v8
 

src/codegen/x64/macro-assembler-x64.cc

@@ -58,19 +58,6 @@ Operand StackArgumentsAccessor::GetArgumentOperand(int index) {
   }
 }
 
-StackArgumentsAccessor::StackArgumentsAccessor(
-    Register base_reg, const ParameterCount& parameter_count,
-    StackArgumentsAccessorReceiverMode receiver_mode,
-    int extra_displacement_to_last_argument)
-    : base_reg_(base_reg),
-      argument_count_reg_(parameter_count.is_reg() ? parameter_count.reg()
-                                                   : no_reg),
-      argument_count_immediate_(
-          parameter_count.is_immediate() ? parameter_count.immediate() : 0),
-      receiver_mode_(receiver_mode),
-      extra_displacement_to_last_argument_(
-          extra_displacement_to_last_argument) {}
-
 void MacroAssembler::Load(Register destination, ExternalReference source) {
   if (root_array_available_ && options().enable_root_array_delta_access) {
     intptr_t delta = RootRegisterOffsetForExternalReference(isolate(), source);
@@ -2282,32 +2269,17 @@ void MacroAssembler::MaybeDropFrames() {
   bind(&dont_drop);
 }
 
-void TurboAssembler::PrepareForTailCall(const ParameterCount& callee_args_count,
-                                        Register caller_args_count_reg,
+void TurboAssembler::PrepareForTailCall(Register callee_args_count,
+                                        Register caller_args_count,
                                         Register scratch0, Register scratch1) {
-#if DEBUG
-  if (callee_args_count.is_reg()) {
-    DCHECK(!AreAliased(callee_args_count.reg(), caller_args_count_reg, scratch0,
-                       scratch1));
-  } else {
-    DCHECK(!AreAliased(caller_args_count_reg, scratch0, scratch1));
-  }
-#endif
+  DCHECK(!AreAliased(callee_args_count, caller_args_count, scratch0, scratch1));
 
   // Calculate the destination address where we will put the return address
   // after we drop current frame.
   Register new_sp_reg = scratch0;
-  if (callee_args_count.is_reg()) {
-    subq(caller_args_count_reg, callee_args_count.reg());
-    leaq(new_sp_reg,
-         Operand(rbp, caller_args_count_reg, times_system_pointer_size,
-                 StandardFrameConstants::kCallerPCOffset));
-  } else {
-    leaq(new_sp_reg,
-         Operand(rbp, caller_args_count_reg, times_system_pointer_size,
-                 StandardFrameConstants::kCallerPCOffset -
-                     callee_args_count.immediate() * kSystemPointerSize));
-  }
+  subq(caller_args_count, callee_args_count);
+  leaq(new_sp_reg, Operand(rbp, caller_args_count, times_system_pointer_size,
+                           StandardFrameConstants::kCallerPCOffset));
 
   if (FLAG_debug_code) {
     cmpq(rsp, new_sp_reg);
@@ -2326,13 +2298,8 @@ void TurboAssembler::PrepareForTailCall(const ParameterCount& callee_args_count,
   movq(rbp, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
 
   // +2 here is to copy both receiver and return address.
-  Register count_reg = caller_args_count_reg;
-  if (callee_args_count.is_reg()) {
-    leaq(count_reg, Operand(callee_args_count.reg(), 2));
-  } else {
-    movq(count_reg, Immediate(callee_args_count.immediate() + 2));
-    // TODO(ishell): Unroll copying loop for small immediate values.
-  }
+  Register count_reg = caller_args_count;
+  leaq(count_reg, Operand(callee_args_count, 2));
 
   // Now copy callee arguments to the caller frame going backwards to avoid
   // callee arguments corruption (source and destination areas could overlap).

src/codegen/x64/macro-assembler-x64.h

@@ -51,12 +51,6 @@ class StackArgumentsAccessor {
         extra_displacement_to_last_argument_(
             extra_displacement_to_last_argument) {}
 
-  StackArgumentsAccessor(Register base_reg,
-                         const ParameterCount& parameter_count,
-                         StackArgumentsAccessorReceiverMode receiver_mode =
-                             ARGUMENTS_CONTAIN_RECEIVER,
-                         int extra_displacement_to_last_argument = 0);
-
   Operand GetArgumentOperand(int index);
   Operand GetReceiverOperand() {
     DCHECK(receiver_mode_ == ARGUMENTS_CONTAIN_RECEIVER);
@@ -485,10 +479,10 @@ class V8_EXPORT_PRIVATE TurboAssembler : public TurboAssemblerBase {
 
   // 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_reg| do not include receiver.
-  // |callee_args_count| is not modified, |caller_args_count_reg| is trashed.
-  void PrepareForTailCall(const ParameterCount& callee_args_count,
-                          Register caller_args_count_reg, Register scratch0,
+  // |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);
 
   // Call a runtime routine. This expects {centry} to contain a fitting CEntry

src/common/globals.h

@@ -628,7 +628,6 @@ class FullObjectSlot;
 class FullMaybeObjectSlot;
 class FullHeapObjectSlot;
 class OldSpace;
-class ParameterCount;
 class ReadOnlySpace;
 class RelocInfo;
 class Scope;

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

@@ -535,9 +535,7 @@ void CodeGenerator::AssemblePopArgumentsAdaptorFrame(Register args_reg,
          MemOperand(fp, ArgumentsAdaptorFrameConstants::kLengthOffset));
   __ SmiUntag(caller_args_count_reg);
 
-  ParameterCount callee_args_count(args_reg);
-  __ PrepareForTailCall(callee_args_count, caller_args_count_reg, scratch2,
-                        scratch3);
+  __ PrepareForTailCall(args_reg, caller_args_count_reg, scratch2, scratch3);
   __ bind(&done);
 }
 

src/compiler/backend/arm64/code-generator-arm64.cc

@@ -529,9 +529,7 @@ void CodeGenerator::AssemblePopArgumentsAdaptorFrame(Register args_reg,
          MemOperand(fp, ArgumentsAdaptorFrameConstants::kLengthOffset));
   __ SmiUntag(caller_args_count_reg);
 
-  ParameterCount callee_args_count(args_reg);
-  __ PrepareForTailCall(callee_args_count, caller_args_count_reg, scratch2,
-                        scratch3);
+  __ PrepareForTailCall(args_reg, caller_args_count_reg, scratch2, scratch3);
   __ bind(&done);
 }
 

src/compiler/backend/ia32/code-generator-ia32.cc

@@ -533,9 +533,8 @@ void CodeGenerator::AssemblePopArgumentsAdaptorFrame(Register args_reg,
          Operand(ebp, ArgumentsAdaptorFrameConstants::kLengthOffset));
   __ SmiUntag(caller_args_count_reg);
 
-  ParameterCount callee_args_count(args_reg);
-  __ PrepareForTailCall(callee_args_count, caller_args_count_reg, scratch2,
-                        scratch3, scratch_count);
+  __ PrepareForTailCall(args_reg, caller_args_count_reg, scratch2, scratch3,
+                        scratch_count);
   __ pop(scratch3);
   __ pop(scratch2);
   __ pop(scratch1);

src/compiler/backend/x64/code-generator-x64.cc

@@ -632,9 +632,7 @@ void CodeGenerator::AssemblePopArgumentsAdaptorFrame(Register args_reg,
   __ SmiUntag(caller_args_count_reg,
               Operand(rbp, ArgumentsAdaptorFrameConstants::kLengthOffset));
 
-  ParameterCount callee_args_count(args_reg);
-  __ PrepareForTailCall(callee_args_count, caller_args_count_reg, scratch2,
-                        scratch3);
+  __ PrepareForTailCall(args_reg, caller_args_count_reg, scratch2, scratch3);
   __ bind(&done);
 }