[turbofan] Better and more sane support for tail calls

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

Index: src/compiler/arm/code-generator-arm.cc
diff --git a/src/compiler/arm/code-generator-arm.cc b/src/compiler/arm/code-generator-arm.cc
index 44d70dcd128fb62613d00809f17954f25977145a..7b848ac812b5bd54ae83a21ec4be87ce9b5a9597 100644
--- a/src/compiler/arm/code-generator-arm.cc
+++ b/src/compiler/arm/code-generator-arm.cc
@@ -354,12 +354,16 @@ Condition FlagsConditionToCondition(FlagsCondition condition) {
   } while (0)
 
 
-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) {
     __ LeaveFrame(StackFrame::MANUAL);
   }
+  if (stack_param_delta < 0) {
+    int offset = -stack_param_delta * kPointerSize;
+    __ add(sp, sp, Operand(offset));
+  }
 }
 
 
@@ -385,7 +389,8 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       break;
     }
     case kArchTailCallCodeObject: {
-      AssembleDeconstructActivationRecord();
+      int stack_param_delta = i.InputInt32(instr->InputCount() - 1);
+      AssembleDeconstructActivationRecord(stack_param_delta);
       if (instr->InputAt(0)->IsImmediate()) {
         __ Jump(Handle<Code>::cast(i.InputHeapObject(0)),
                 RelocInfo::CODE_TARGET);
@@ -420,7 +425,8 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
         __ cmp(cp, kScratchReg);
         __ Assert(eq, kWrongFunctionContext);
       }
-      AssembleDeconstructActivationRecord();
+      int stack_param_delta = i.InputInt32(instr->InputCount() - 1);
+      AssembleDeconstructActivationRecord(stack_param_delta);
       __ ldr(ip, FieldMemOperand(func, JSFunction::kCodeEntryOffset));
       __ Jump(ip);
       DCHECK_EQ(LeaveCC, i.OutputSBit());