PPC: [turbofan] Add basic support for calling to (a subset of) C functions.

src/compiler/ppc/instruction-selector-ppc.cc

Index: src/compiler/ppc/instruction-selector-ppc.cc
diff --git a/src/compiler/ppc/instruction-selector-ppc.cc b/src/compiler/ppc/instruction-selector-ppc.cc
index 0f45647865df3ae57cdeb762c66f5a2f66797ccc..300e27fe6f07aca3be7d0981566000132a3e55d7 100644
--- a/src/compiler/ppc/instruction-selector-ppc.cc
+++ b/src/compiler/ppc/instruction-selector-ppc.cc
@@ -1442,12 +1442,35 @@ void InstructionSelector::VisitCall(Node* node, BasicBlock* handler) {
   // TODO(turbofan): on PPC it's probably better to use the code object in a
   // register if there are multiple uses of it. Improve constant pool and the
   // heuristics in the register allocator for where to emit constants.
-  InitializeCallBuffer(node, &buffer, true, false);
-
-  // Push any stack arguments.
-  // TODO(mbrandy): reverse order and use push only for first
-  for (Node* node : base::Reversed(buffer.pushed_nodes)) {
-    Emit(kPPC_Push, g.NoOutput(), g.UseRegister(node));
+  InitializeCallBuffer(node, &buffer, true, true);
+
+  // Prepare for C function call.
+  if (descriptor->IsCFunctionCall()) {
+    Emit(kArchPrepareCallCFunction |
+             MiscField::encode(static_cast<int>(descriptor->CParameterCount())),
+         0, nullptr, 0, nullptr);
+
+    // Poke any stack arguments.
+    int slot = kStackFrameExtraParamSlot;
+    for (Node* node : buffer.pushed_nodes) {
+      Emit(kPPC_StoreToStackSlot, g.NoOutput(), g.UseRegister(node),
+           g.TempImmediate(slot));
+      ++slot;
+    }
+  } else {
+    // Push any stack arguments.
+    int num_slots = buffer.pushed_nodes.size();
+    int slot = 0;
+    for (Node* node : buffer.pushed_nodes) {
+      if (slot == 0) {
+        Emit(kPPC_PushFrame, g.NoOutput(), g.UseRegister(node),
+             g.TempImmediate(num_slots));
+      } else {
+        Emit(kPPC_StoreToStackSlot, g.NoOutput(), g.UseRegister(node),
+             g.TempImmediate(slot));
+      }
+      ++slot;
+    }
   }
 
   // Pass label of exception handler block.
@@ -1465,18 +1488,21 @@ void InstructionSelector::VisitCall(Node* node, BasicBlock* handler) {
   // Select the appropriate opcode based on the call type.
   InstructionCode opcode;
   switch (descriptor->kind()) {
-    case CallDescriptor::kCallCodeObject: {
-      opcode = kArchCallCodeObject;
+    case CallDescriptor::kCallAddress:
+      opcode =
+          kArchCallCFunction |
+          MiscField::encode(static_cast<int>(descriptor->CParameterCount()));
+      break;
+    case CallDescriptor::kCallCodeObject:
+      opcode = kArchCallCodeObject | MiscField::encode(flags);
       break;
-    }
     case CallDescriptor::kCallJSFunction:
-      opcode = kArchCallJSFunction;
+      opcode = kArchCallJSFunction | MiscField::encode(flags);
       break;
     default:
       UNREACHABLE();
       return;
   }
-  opcode |= MiscField::encode(flags);
 
   // Emit the call instruction.
   size_t const output_count = buffer.outputs.size();