[turbofan] Better and more sane support for tail calls

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

 // Copyright 2013 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/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/osr.h"
@@ skipping 555 matching lines @@
     if (instr->InputAt(4)->IsRegister()) {                       \
       Register value = i.InputRegister(4);                       \
       ASSEMBLE_CHECKED_STORE_INTEGER_IMPL(asm_instr, Register);  \
     } else {                                                     \
       Immediate value = i.InputImmediate(4);                     \
       ASSEMBLE_CHECKED_STORE_INTEGER_IMPL(asm_instr, Immediate); \
     }                                                            \
   } while (false)
 
 
-void CodeGenerator::AssembleDeconstructActivationRecord() {
+void CodeGenerator::AssembleDeconstructActivationRecord(int stack_param_delta) {
   CallDescriptor* descriptor = linkage()->GetIncomingDescriptor();
   int stack_slots = frame()->GetSpillSlotCount();
   if (descriptor->IsJSFunctionCall() || stack_slots > 0) {
     __ movq(rsp, rbp);
     __ popq(rbp);
   }
+  if (stack_param_delta < 0) {
+    int offset = -(stack_param_delta + 1) * kPointerSize;
+    __ popq(Operand(rsp, offset));
+    if (offset != 0) {
+      __ addq(rsp, Immediate(offset));
+    }
+  }
 }
 
 
 // Assembles an instruction after register allocation, producing machine code.
 void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
   X64OperandConverter i(this, instr);
 
   switch (ArchOpcodeField::decode(instr->opcode())) {
     case kArchCallCodeObject: {
       EnsureSpaceForLazyDeopt();
       if (HasImmediateInput(instr, 0)) {
         Handle<Code> code = Handle<Code>::cast(i.InputHeapObject(0));
         __ Call(code, RelocInfo::CODE_TARGET);
       } else {
         Register reg = i.InputRegister(0);
         __ addp(reg, Immediate(Code::kHeaderSize - kHeapObjectTag));
         __ call(reg);
       }
       RecordCallPosition(instr);
       break;
     }
     case kArchTailCallCodeObject: {
-      AssembleDeconstructActivationRecord();
+      int stack_param_delta = i.InputInt32(instr->InputCount() - 1);
+      AssembleDeconstructActivationRecord(stack_param_delta);
       if (HasImmediateInput(instr, 0)) {
         Handle<Code> code = Handle<Code>::cast(i.InputHeapObject(0));
         __ jmp(code, RelocInfo::CODE_TARGET);
       } else {
         Register reg = i.InputRegister(0);
         __ addp(reg, Immediate(Code::kHeaderSize - kHeapObjectTag));
         __ jmp(reg);
       }
       break;
     }
     case kArchCallJSFunction: {
       EnsureSpaceForLazyDeopt();
       Register func = i.InputRegister(0);
       if (FLAG_debug_code) {
         // Check the function's context matches the context argument.
         __ cmpp(rsi, FieldOperand(func, JSFunction::kContextOffset));
         __ Assert(equal, kWrongFunctionContext);
       }
       __ Call(FieldOperand(func, JSFunction::kCodeEntryOffset));
       RecordCallPosition(instr);
       break;
     }
     case kArchTailCallJSFunction: {
       Register func = i.InputRegister(0);
       if (FLAG_debug_code) {
         // Check the function's context matches the context argument.
         __ cmpp(rsi, FieldOperand(func, JSFunction::kContextOffset));
         __ Assert(equal, kWrongFunctionContext);
       }
-      AssembleDeconstructActivationRecord();
+      int stack_param_delta = i.InputInt32(instr->InputCount() - 1);
+      AssembleDeconstructActivationRecord(stack_param_delta);
       __ jmp(FieldOperand(func, JSFunction::kCodeEntryOffset));
       break;
     }
     case kArchLazyBailout: {
       EnsureSpaceForLazyDeopt();
       RecordCallPosition(instr);
       break;
     }
     case kArchPrepareCallCFunction: {
       int const num_parameters = MiscField::decode(instr->opcode());
@@ skipping 1269 matching lines @@
     int padding_size = last_lazy_deopt_pc_ + space_needed - current_pc;
     __ Nop(padding_size);
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8