[turbofan, arm64] Fix native stack parameters on arm64.

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

Index: src/compiler/arm64/code-generator-arm64.cc
diff --git a/src/compiler/arm64/code-generator-arm64.cc b/src/compiler/arm64/code-generator-arm64.cc
index 928b2c6dbb93dfd7658334eeed810a72a2d161cf..6e90c0529e6c4a3b7fb8530eb4d3d1f06850e727 100644
--- a/src/compiler/arm64/code-generator-arm64.cc
+++ b/src/compiler/arm64/code-generator-arm64.cc
@@ -877,12 +877,22 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
     }
     case kArm64Poke: {
       Operand operand(i.InputInt32(1) * kPointerSize);
-      __ Poke(i.InputRegister(0), operand);
+      if (instr->InputAt(0)->IsDoubleRegister()) {
+        __ Poke(i.InputFloat64Register(0), operand);
+      } else {
+        __ Poke(i.InputRegister(0), operand);
+      }
       break;
     }
     case kArm64PokePair: {
       int slot = i.InputInt32(2) - 1;
-      __ PokePair(i.InputRegister(1), i.InputRegister(0), slot * kPointerSize);
+      if (instr->InputAt(0)->IsDoubleRegister()) {
+        __ PokePair(i.InputFloat64Register(1), i.InputFloat64Register(0),

[jbramley, 2015/12/03 11:22:34]

Consider: DCHECK(instr->InputAt(1)->IsDoubleRegister());

Also, the reverse in the "else" case.

[ahaas, 2015/12/03 15:25:06]

I didn't add this DCHECK because i.InputFloat64Register(1) in the next line
crashes anyways if the DCHECK would fail. 

+                    slot * kPointerSize);
+      } else {
+        __ PokePair(i.InputRegister(1), i.InputRegister(0),
+                    slot * kPointerSize);
+      }
       break;
     }
     case kArm64Clz:
@@ -1292,9 +1302,16 @@ void CodeGenerator::AssemblePrologue() {
     __ SetStackPointer(jssp);
     __ Prologue(info->IsCodePreAgingActive());
   } else if (frame()->needs_frame()) {
-    __ SetStackPointer(jssp);
+    if (descriptor->UseNativeStack()) {
+      __ SetStackPointer(csp);
+    } else {
+      __ SetStackPointer(jssp);
+    }
     __ StubPrologue();
   } else {
+    if (descriptor->UseNativeStack()) {
+      __ SetStackPointer(csp);

[jbramley, 2015/12/03 11:22:34]

Is it jssp by default? (I can't remember.) If it is jssp by default, then surely
we don't need to SetStackPointer(jssp) in the needs_frame() case above.

[titzer, 2015/12/03 11:31:59]

Actually, I think it's best to be explicit in both of these cases.

[ahaas, 2015/12/03 15:25:06]

Done, I made it explicit in both cases.

+    }
     frame()->SetElidedFrameSizeInSlots(0);
   }
   frame_access_state()->SetFrameAccessToDefault();
@@ -1315,9 +1332,10 @@ void CodeGenerator::AssemblePrologue() {
     stack_shrink_slots -= OsrHelper(info()).UnoptimizedFrameSlots();
   }
 
-  if (csp.Is(masm()->StackPointer())) {
+  if (csp.Is(masm()->StackPointer()) && !descriptor->UseNativeStack()) {

[jbramley, 2015/12/03 11:22:34]

Why not for the UseNativeStack() case?

In particular, if csp is left without 16-byte alignment, subsequent stack
operations will fail. (The restriction is more severe than described in the
comment.)

[ahaas, 2015/12/03 15:25:06]

The additional condition is required because AlignSavedCalleeRegisterSlots sets
frame()->needs_frame() to true, which causes problems later in AssembleReturn.

I changed the condition to "if (csp.Is(masm()->StackPointer()) &&
frame()->needs_frame())" now. This is correct, because when
frame()->needs_frame() is false, then the call to AlignSavedCalleeRegisterSlots
is guaranteed to return 0.

     // The system stack pointer requires 16-byte alignment at function call
     // boundaries.
+
     stack_shrink_slots += frame()->AlignSavedCalleeRegisterSlots();
   }
   __ Claim(stack_shrink_slots);
@@ -1374,9 +1392,18 @@ void CodeGenerator::AssembleReturn() {
       return;
     } else {
       __ Bind(&return_label_);
-      __ Mov(jssp, fp);
+      if (descriptor->UseNativeStack()) {
+        __ Mov(csp, fp);
+      } else {
+        __ Mov(jssp, fp);
+      }
       __ Pop(fp, lr);
     }
+  } else if (descriptor->UseNativeStack()) {
+    bool pop_count_uneven = pop_count & 1;
+    if (pop_count_uneven) {
+      pop_count++;
+    }

[jbramley, 2015/12/03 11:22:34]

Why not just "pop_count += (pop_count & 1)"?

[ahaas, 2015/12/03 15:25:06]

Done.

   }
   __ Drop(pop_count);
   __ Ret();