Pass closure object as first implicit argument to closure functions.

runtime/vm/stub_code_x64.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/assembler.h"
 #include "vm/assembler_macros.h"
 #include "vm/compiler.h"
 #include "vm/flow_graph_compiler.h"
 #include "vm/instructions.h"
 #include "vm/object_store.h"
 #include "vm/pages.h"
 #include "vm/resolver.h"
 #include "vm/scavenger.h"
 #include "vm/stub_code.h"
 
 
 #define __ assembler->
 
 namespace dart {
 
 DEFINE_FLAG(bool, inline_alloc, true, "Inline allocation of objects.");
 DEFINE_FLAG(bool, use_slow_path, false,
     "Set to true for debugging & verifying the slow paths.");
 DECLARE_FLAG(int, optimization_counter_threshold);
 
-
 // Input parameters:
 //   RSP : points to return address.
 //   RSP + 8 : address of last argument in argument array.
 //   RSP + 8*R10 : address of first argument in argument array.
 //   RSP + 8*R10 + 8 : address of return value.
 //   RBX : address of the runtime function to call.
 //   R10 : number of arguments to the call.
 // Must preserve callee saved registers R12 and R13.
 void StubCode::GenerateCallToRuntimeStub(Assembler* assembler) {
   ASSERT((R12 != CTX) && (R13 != CTX));
   const intptr_t isolate_offset = NativeArguments::isolate_offset();
-  const intptr_t argc_offset = NativeArguments::argc_offset();
+  const intptr_t argc_tag_offset = NativeArguments::argc_tag_offset();
   const intptr_t argv_offset = NativeArguments::argv_offset();
   const intptr_t retval_offset = NativeArguments::retval_offset();
 
   __ EnterFrame(0);
 
   // Load current Isolate pointer from Context structure into RAX.
   __ movq(RAX, FieldAddress(CTX, Context::isolate_offset()));
 
   // Save exit frame information to enable stack walking as we are about
   // to transition to Dart VM C++ code.
   __ movq(Address(RAX, Isolate::top_exit_frame_info_offset()), RSP);
 
   // Save current Context pointer into Isolate structure.
   __ movq(Address(RAX, Isolate::top_context_offset()), CTX);
 
   // Cache Isolate pointer into CTX while executing runtime code.
   __ movq(CTX, RAX);
 
   // Reserve space for arguments and align frame before entering C++ world.
   __ AddImmediate(RSP, Immediate(-sizeof(NativeArguments)));
   if (OS::ActivationFrameAlignment() > 0) {
     __ andq(RSP, Immediate(~(OS::ActivationFrameAlignment() - 1)));
   }
 
   // Pass NativeArguments structure by value and call runtime.
   __ movq(Address(RSP, isolate_offset), CTX);  // Set isolate in NativeArgs.
-  __ movq(Address(RSP, argc_offset), R10);  // Set argc in NativeArguments.
+  // There are no runtime calls to closures, so we do not need to set the tag
+  // bits kClosureFunctionBit and kInstanceFunctionBit in argc_tag_.
+  __ movq(Address(RSP, argc_tag_offset), R10);  // Set argc in NativeArguments.
   __ leaq(RAX, Address(RBP, R10, TIMES_8, 1 * kWordSize));  // Compute argv.
   __ movq(Address(RSP, argv_offset), RAX);  // Set argv in NativeArguments.
   __ addq(RAX, Immediate(1 * kWordSize));  // Retval is next to 1st argument.
   __ movq(Address(RSP, retval_offset), RAX);  // Set retval in NativeArguments.
   __ call(RBX);
 
   // Reset exit frame information in Isolate structure.
   __ movq(Address(CTX, Isolate::top_exit_frame_info_offset()), Immediate(0));
 
   // Load Context pointer from Isolate structure into RBX.
@@ skipping 29 matching lines @@
   __ CallRuntime(kPrintStopMessageRuntimeEntry);
   __ LeaveCallRuntimeFrame();
   __ ret();
 }
 
 
 // Input parameters:
 //   RSP : points to return address.
 //   RSP + 8 : address of return value.
 //   RAX : address of first argument in argument array.
-//   RAX - 8*R10 + 8 : address of last argument in argument array.
 //   RBX : address of the native function to call.
-//   R10 : number of arguments to the call.
+//   R10 : argc_tag including number of arguments and function kind.
 void StubCode::GenerateCallNativeCFunctionStub(Assembler* assembler) {
   const intptr_t native_args_struct_offset = 0;
   const intptr_t isolate_offset =
       NativeArguments::isolate_offset() + native_args_struct_offset;
-  const intptr_t argc_offset =
-      NativeArguments::argc_offset() + native_args_struct_offset;
+  const intptr_t argc_tag_offset =
+      NativeArguments::argc_tag_offset() + native_args_struct_offset;
   const intptr_t argv_offset =
       NativeArguments::argv_offset() + native_args_struct_offset;
   const intptr_t retval_offset =
       NativeArguments::retval_offset() + native_args_struct_offset;
 
   __ EnterFrame(0);
 
   // Load current Isolate pointer from Context structure into R8.
   __ movq(R8, FieldAddress(CTX, Context::isolate_offset()));
 
@@ skipping 10 matching lines @@
   // Reserve space for the native arguments structure passed on the stack (the
   // outgoing pointer parameter to the native arguments structure is passed in
   // RDI) and align frame before entering the C++ world.
   __ AddImmediate(RSP, Immediate(-sizeof(NativeArguments)));
   if (OS::ActivationFrameAlignment() > 0) {
     __ andq(RSP, Immediate(~(OS::ActivationFrameAlignment() - 1)));
   }
 
   // Pass NativeArguments structure by value and call native function.
   __ movq(Address(RSP, isolate_offset), CTX);  // Set isolate in NativeArgs.
-  __ movq(Address(RSP, argc_offset), R10);  // Set argc in NativeArguments.
+  __ movq(Address(RSP, argc_tag_offset), R10);  // Set argc in NativeArguments.
   __ movq(Address(RSP, argv_offset), RAX);  // Set argv in NativeArguments.
   __ leaq(RAX, Address(RBP, 2 * kWordSize));  // Compute return value addr.
   __ movq(Address(RSP, retval_offset), RAX);  // Set retval in NativeArguments.
   __ movq(RDI, RSP);  // Pass the pointer to the NativeArguments.
   __ call(RBX);
 
   // Reset exit frame information in Isolate structure.
   __ movq(Address(CTX, Isolate::top_exit_frame_info_offset()), Immediate(0));
 
   // Load Context pointer from Isolate structure into R8.
@@ skipping 543 matching lines @@
   __ popq(RAX);  // Pop element type argument.
   __ popq(R10);  // Pop array length argument.
   __ popq(RAX);  // Pop return value from return slot.
   __ LeaveFrame();
   __ ret();
 }
 
 
 // Input parameters:
 //   R10: Arguments descriptor array (num_args is first Smi element, closure
-//        object is not included in num_args).
-// Note: The closure object is pushed before the first argument to the function
-//       being called, the stub accesses the closure from this location directly
-//       when setting up the context and resolving the entry point.
+//        object is included in num_args and is first argument).
+// Note: The closure object is the first argument to the function being
+//       called, the stub accesses the closure from this location directly
+//       when trying to resolve the call.
 void StubCode::GenerateCallClosureFunctionStub(Assembler* assembler) {
   const Immediate raw_null =
       Immediate(reinterpret_cast<intptr_t>(Object::null()));
 
   // Total number of args is the first Smi in args descriptor array (R10).
   __ movq(RAX, FieldAddress(R10, Array::data_offset()));  // Load num_args.
   // Load closure object in R13.
-  __ movq(R13, Address(RSP, RAX, TIMES_4, kWordSize));  // RAX is a Smi.
+  __ movq(R13, Address(RSP, RAX, TIMES_4, 0));  // RAX is a Smi.
 
   // Verify that R13 is a closure by checking its class.
   Label not_closure;
   __ cmpq(R13, raw_null);
   // Not a closure, but null object.
   __ j(EQUAL, &not_closure);
   __ testq(R13, Immediate(kSmiTagMask));
   __ j(ZERO, &not_closure);  // Not a closure, but a smi.
   // Verify that the class of the object is a closure class by checking that
   // class.signature_function() is not null.
@@ skipping 37 matching lines @@
 
   __ movq(RBX, FieldAddress(RAX, Code::instructions_offset()));
   __ addq(RBX, Immediate(Instructions::HeaderSize() - kHeapObjectTag));
   __ jmp(RBX);
 
   __ Bind(&not_closure);
   // Call runtime to report that a closure call was attempted on a non-closure
   // object, passing the non-closure object and its arguments array.
   // R13: non-closure object.
   // R10: arguments descriptor array (num_args is first Smi element, closure
-  //      object is not included in num_args).
+  //      object is included in num_args).
 
   // Create a stub frame as we are pushing some objects on the stack before
   // calling into the runtime.
   AssemblerMacros::EnterStubFrame(assembler);
 
   __ pushq(raw_null);  // Setup space on stack for result from error reporting.
   __ pushq(R13);  // Non-closure object.
     // Total number of args is the first Smi in args descriptor array (R10).
   __ movq(R13, FieldAddress(R10, Array::data_offset()));  // Load num_args.
   __ SmiUntag(R13);
+  __ subq(R13, Immediate(1));  // Arguments array length, minus the closure.
   // See stack layout below explaining "wordSize * 5" offset.
   PushArgumentsArray(assembler, (kWordSize * 5));
 
   // Stack:
   // TOS + 0: Argument array.
   // TOS + 1: Non-closure object.
   // TOS + 2: Place for result from reporting the error.
   // TOS + 3: PC marker => RawInstruction object.
   // TOS + 4: Saved RBP of previous frame. <== RBP
   // TOS + 5: Dart code return address
@@ skipping 1214 matching lines @@
   __ CallRuntime(kUpdateICDataTwoArgsRuntimeEntry);
   __ Drop(4);
   __ LeaveFrame();
 
   __ jmp(&compute_result, Assembler::kNearJump);
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64