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

src/compiler/arm/code-generator-arm.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/arm/macro-assembler-arm.h"
 #include "src/compilation-info.h"
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
@@ skipping 726 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));
       DCHECK_EQ(LeaveCC, i.OutputSBit());
       break;
     case kArchStackPointer:
       __ mov(i.OutputRegister(), sp);
       DCHECK_EQ(LeaveCC, i.OutputSBit());
       break;
     case kArchFramePointer:
       __ mov(i.OutputRegister(), fp);
       DCHECK_EQ(LeaveCC, i.OutputSBit());
       break;
@@ skipping 972 matching lines @@
   }
   const RegList saves = FLAG_enable_embedded_constant_pool
                             ? (descriptor->CalleeSavedRegisters() & ~pp.bit())
                             : descriptor->CalleeSavedRegisters();
   if (saves != 0) {
     // Save callee-saved registers.
     __ stm(db_w, sp, saves);
   }
 }
 
-
-void CodeGenerator::AssembleReturn() {
+void CodeGenerator::AssembleReturn(InstructionOperand* pop) {
   CallDescriptor* descriptor = linkage()->GetIncomingDescriptor();
   int pop_count = static_cast<int>(descriptor->StackParameterCount());
 
   // Restore registers.
   const RegList saves = FLAG_enable_embedded_constant_pool
                             ? (descriptor->CalleeSavedRegisters() & ~pp.bit())
                             : descriptor->CalleeSavedRegisters();
   if (saves != 0) {
     __ ldm(ia_w, sp, saves);
   }
 
   // Restore FP registers.
   const RegList saves_fp = descriptor->CalleeSavedFPRegisters();
   if (saves_fp != 0) {
     STATIC_ASSERT(DwVfpRegister::kMaxNumRegisters == 32);
     uint32_t last = base::bits::CountLeadingZeros32(saves_fp) - 1;
     uint32_t first = base::bits::CountTrailingZeros32(saves_fp);
     __ vldm(ia_w, sp, DwVfpRegister::from_code(first),
             DwVfpRegister::from_code(last));
   }
 
   unwinding_info_writer_.MarkBlockWillExit();
 
+  ArmOperandConverter g(this, nullptr);
   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();
+      }
     } else {
-      __ bind(&return_label_);
       AssembleDeconstructFrame();
     }
   }
-  __ Ret(pop_count);
+
+  if (pop->IsImmediate()) {
+    DCHECK_EQ(Constant::kInt32, g.ToConstant(pop).type());
+    pop_count += g.ToConstant(pop).ToInt32();
+  } else {
+    __ Drop(g.ToRegister(pop));
+  }
+  __ Drop(pop_count);
+  __ Ret();
 }
 
 void CodeGenerator::AssembleMove(InstructionOperand* source,
                                  InstructionOperand* destination) {
   ArmOperandConverter g(this, nullptr);
   // Dispatch on the source and destination operand kinds.  Not all
   // combinations are possible.
   if (source->IsRegister()) {
     DCHECK(destination->IsRegister() || destination->IsStackSlot());
     Register src = g.ToRegister(source);
@@ skipping 248 matching lines @@
       padding_size -= v8::internal::Assembler::kInstrSize;
     }
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8