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

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

Index: src/compiler/mips/instruction-selector-mips.cc
diff --git a/src/compiler/mips/instruction-selector-mips.cc b/src/compiler/mips/instruction-selector-mips.cc
index c042ea11e67de559428dfb716773aa78259ae80d..ce40753995db0a93dded1fd3b1c8e03b1b6a4f84 100644
--- a/src/compiler/mips/instruction-selector-mips.cc
+++ b/src/compiler/mips/instruction-selector-mips.cc
@@ -524,18 +524,34 @@ void InstructionSelector::VisitCall(Node* node, BasicBlock* handler) {
   CallBuffer buffer(zone(), descriptor, frame_state_descriptor);
 
   // Compute InstructionOperands for inputs and outputs.
-  InitializeCallBuffer(node, &buffer, true, false);
-  // Possibly align stack here for functions.
-  int push_count = buffer.pushed_nodes.size();
-  if (push_count > 0) {
-    Emit(kMipsStackClaim, g.NoOutput(),
-         g.TempImmediate(push_count << kPointerSizeLog2));
-  }
-  int slot = buffer.pushed_nodes.size() - 1;
-  for (Node* node : base::Reversed(buffer.pushed_nodes)) {
-    Emit(kMipsStoreToStackSlot, g.NoOutput(), g.UseRegister(node),
-         g.TempImmediate(slot << kPointerSizeLog2));
-    slot--;
+  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 = kCArgSlotCount;
+    for (Node* node : buffer.pushed_nodes) {
+      Emit(kMipsStoreToStackSlot, g.NoOutput(), g.UseRegister(node),
+           g.TempImmediate(slot << kPointerSizeLog2));
+      ++slot;
+    }
+  } else {
+    // Possibly align stack here for functions.
+    int push_count = buffer.pushed_nodes.size();
+    if (push_count > 0) {
+      Emit(kMipsStackClaim, g.NoOutput(),
+           g.TempImmediate(push_count << kPointerSizeLog2));
+    }
+    int slot = buffer.pushed_nodes.size() - 1;
+    for (Node* node : base::Reversed(buffer.pushed_nodes)) {
+      Emit(kMipsStoreToStackSlot, g.NoOutput(), g.UseRegister(node),
+           g.TempImmediate(slot << kPointerSizeLog2));
+      slot--;
+    }
   }
 
   // Pass label of exception handler block.
@@ -553,18 +569,21 @@ 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();