[turbofan] Support variable size argument popping in TF-generated functions

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

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/code-generator.h"
 
 #include "src/arm64/frames-arm64.h"
 #include "src/arm64/macro-assembler-arm64.h"
 #include "src/compilation-info.h"
 #include "src/compiler/code-generator-impl.h"
@@ skipping 765 matching lines @@
       int deopt_state_id =
           BuildTranslation(instr, -1, 0, OutputFrameStateCombine::Ignore());
       Deoptimizer::BailoutType bailout_type =
           Deoptimizer::BailoutType(MiscField::decode(instr->opcode()));
       CodeGenResult result = AssembleDeoptimizerCall(
           deopt_state_id, bailout_type, current_source_position_);
       if (result != kSuccess) return result;
       break;
     }
     case kArchRet:
-      AssembleReturn();
+      AssembleReturn(instr->InputAt(0));
       break;
     case kArchStackPointer:
       __ mov(i.OutputRegister(), masm()->StackPointer());
       break;
     case kArchFramePointer:
       __ mov(i.OutputRegister(), fp);
       break;
     case kArchParentFramePointer:
       if (frame_access_state()->has_frame()) {
         __ ldr(i.OutputRegister(), MemOperand(fp, 0));
@@ skipping 1050 matching lines @@
   // CPURegList::GetCalleeSaved(): x30 is missing.
   // DCHECK(saves.list() == CPURegList::GetCalleeSaved().list());
   CPURegList saves = CPURegList(CPURegister::kRegister, kXRegSizeInBits,
                                 descriptor->CalleeSavedRegisters());
   saved_count = saves.Count();
   if (saved_count != 0) {
     __ PushCPURegList(saves);
   }
 }
 
-
-void CodeGenerator::AssembleReturn() {
+void CodeGenerator::AssembleReturn(InstructionOperand* pop) {
   CallDescriptor* descriptor = linkage()->GetIncomingDescriptor();
 
   // Restore registers.
   CPURegList saves = CPURegList(CPURegister::kRegister, kXRegSizeInBits,
                                 descriptor->CalleeSavedRegisters());
   if (saves.Count() != 0) {
     __ PopCPURegList(saves);
   }
 
   // Restore fp registers.
   CPURegList saves_fp = CPURegList(CPURegister::kFPRegister, kDRegSizeInBits,
                                    descriptor->CalleeSavedFPRegisters());
   if (saves_fp.Count() != 0) {
     __ PopCPURegList(saves_fp);
   }
 
   unwinding_info_writer_.MarkBlockWillExit();
 
+  Arm64OperandConverter g(this, nullptr);
   int pop_count = static_cast<int>(descriptor->StackParameterCount());
   if (descriptor->IsCFunctionCall()) {
     AssembleDeconstructFrame();
   } else if (frame_access_state()->has_frame()) {
-    // Canonicalize JSFunction return sites for now.
-    if (return_label_.is_bound()) {
-      __ B(&return_label_);
-      return;
+    // Canonicalize JSFunction return sites for now unless they have an variable
+    // number of stack slot pops.
+    if (pop->IsImmediate() && g.ToConstant(pop).ToInt32() == 0) {
+      if (return_label_.is_bound()) {
+        __ B(&return_label_);
+        return;
+      } else {
+        __ Bind(&return_label_);
+        AssembleDeconstructFrame();
+        if (descriptor->UseNativeStack()) {
+          pop_count += (pop_count & 1);  // align
+        }
+      }
     } else {
-      __ Bind(&return_label_);
       AssembleDeconstructFrame();
       if (descriptor->UseNativeStack()) {
         pop_count += (pop_count & 1);  // align
       }
     }
   } else if (descriptor->UseNativeStack()) {
     pop_count += (pop_count & 1);  // align
   }
-  __ Drop(pop_count);
+
+  if (pop->IsImmediate()) {
+    DCHECK_EQ(Constant::kInt32, g.ToConstant(pop).type());
+    pop_count += g.ToConstant(pop).ToInt32();
+    __ Drop(pop_count);
+  } else {
+    Register pop_reg = g.ToRegister(pop);
+    __ Add(pop_reg, pop_reg, pop_count);
+    __ Drop(pop_reg);
+  }
 
   if (descriptor->UseNativeStack()) {
     __ AssertCspAligned();
   }
   __ Ret();
 }
 
 
 void CodeGenerator::AssembleMove(InstructionOperand* source,
                                  InstructionOperand* destination) {
@@ skipping 179 matching lines @@
       padding_size -= kInstructionSize;
     }
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8