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

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

Index: src/compiler/arm/instruction-selector-arm.cc
diff --git a/src/compiler/arm/instruction-selector-arm.cc b/src/compiler/arm/instruction-selector-arm.cc
index 6fb0c5b5d5f61d8ef88418f8c86b191030f0613f..b5324544600c506a69813c309e691a49e3d8bb9d 100644
--- a/src/compiler/arm/instruction-selector-arm.cc
+++ b/src/compiler/arm/instruction-selector-arm.cc
@@ -1096,11 +1096,27 @@ void InstructionSelector::VisitCall(Node* node, BasicBlock* handler) {
   // TODO(turbofan): on ARM 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.
-  for (Node* node : base::Reversed(buffer.pushed_nodes)) {
-    Emit(kArmPush, 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.
+    for (size_t n = 0; n < buffer.pushed_nodes.size(); ++n) {
+      if (Node* node = buffer.pushed_nodes[n]) {
+        int const slot = static_cast<int>(n);
+        InstructionOperand value = g.UseRegister(node);
+        Emit(kArmPoke | MiscField::encode(slot), g.NoOutput(), value);
+      }
+    }
+  } else {
+    // Push any stack arguments.
+    for (Node* node : base::Reversed(buffer.pushed_nodes)) {
+      Emit(kArmPush, g.NoOutput(), g.UseRegister(node));
+    }
   }
 
   // Pass label of exception handler block.
@@ -1118,18 +1134,21 @@ 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();