[turbofan]: Implement tail calls with more callee than caller parameters

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/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
@@ skipping 441 matching lines @@
       uint32_t imm =                                                        \
           static_cast<uint32_t>(i.InputOperand##width(1).ImmediateValue()); \
       __ asm_instr(i.OutputRegister##width(), i.InputRegister##width(0),    \
                    imm % (width));                                          \
     }                                                                       \
   } while (0)
 
 
 void CodeGenerator::AssembleDeconstructActivationRecord(int stack_param_delta) {
   CallDescriptor* descriptor = linkage()->GetIncomingDescriptor();
-  int stack_slots = frame()->GetSpillSlotCount();
-  if (descriptor->IsJSFunctionCall() || stack_slots > 0) {
-    __ Mov(jssp, fp);
+  int spill_slots = frame()->GetSpillSlotCount();
+  bool has_frame = descriptor->IsJSFunctionCall() || spill_slots > 0;
+  if (has_frame) {
+    if (stack_param_delta != 0) {
+      int total_discarded_slots = frame()->GetTotalFrameSlotCount();
+      // Leave the PC and saved frame pointer on the stack.
+      total_discarded_slots -=
+          StandardFrameConstants::kFixedFrameSizeFromFp / kPointerSize;
+      // Discard only slots that won't be used by new parameters.
+      total_discarded_slots -= stack_param_delta;
+      if (total_discarded_slots > 0) {
+        __ Add(jssp, jssp, Operand(total_discarded_slots * kPointerSize));
+      }
+    } else {
+      __ Mov(jssp, fp);
+    }
     __ Pop(fp, lr);
   }
-  if (stack_param_delta < 0) {
-    int offset = -stack_param_delta * kPointerSize;
-    __ Add(jssp, jssp, Operand(offset));
-  }
 }
 
+
+void CodeGenerator::AssemblePrepareTailCall(int stack_param_delta) {
+  if (stack_param_delta > 0) {
+    int total_discarded_slots = frame()->GetTotalFrameSlotCount();
+    // Leave the PC and saved frame pointer on the stack.
+    total_discarded_slots -=
+        StandardFrameConstants::kFixedFrameSizeFromFp / kPointerSize;
+    // Discard only slots that won't be used by new parameters.
+    total_discarded_slots -= stack_param_delta;
+    if (total_discarded_slots < 0) {
+      __ Sub(jssp, jssp, Operand(-total_discarded_slots * kPointerSize));
+    }
+  }
+}
+
 
 // Assembles an instruction after register allocation, producing machine code.
 void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
   Arm64OperandConverter i(this, instr);
   InstructionCode opcode = instr->opcode();
   switch (ArchOpcodeField::decode(opcode)) {
     case kArchCallCodeObject: {
       EnsureSpaceForLazyDeopt();
       if (instr->InputAt(0)->IsImmediate()) {
         __ Call(Handle<Code>::cast(i.InputHeapObject(0)),
@@ skipping 59 matching lines @@
       EnsureSpaceForLazyDeopt();
       RecordCallPosition(instr);
       break;
     }
     case kArchPrepareCallCFunction:
       // We don't need kArchPrepareCallCFunction on arm64 as the instruction
       // selector already perform a Claim to reserve space on the stack and
       // guarantee correct alignment of stack pointer.
       UNREACHABLE();
       break;
+    case kArchPrepareTailCall:
+      AssemblePrepareTailCall(i.InputInt32(instr->InputCount() - 1));
+      break;
     case kArchCallCFunction: {
       int const num_parameters = MiscField::decode(instr->opcode());
       if (instr->InputAt(0)->IsImmediate()) {
         ExternalReference ref = i.InputExternalReference(0);
         __ CallCFunction(ref, num_parameters, 0);
       } else {
         Register func = i.InputRegister(0);
         __ CallCFunction(func, num_parameters, 0);
       }
       // CallCFunction only supports register arguments so we never need to call
@@ skipping 967 matching lines @@
       padding_size -= kInstructionSize;
     }
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8