Introduce a class encapsulating arguments descriptor arrays.

runtime/vm/flow_graph_compiler_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"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/flow_graph_compiler.h"
 
 #include "lib/error.h"
 #include "vm/ast_printer.h"
+#include "vm/dart_entry.h"
 #include "vm/il_printer.h"
 #include "vm/locations.h"
 #include "vm/object_store.h"
 #include "vm/parser.h"
 #include "vm/stub_code.h"
 #include "vm/symbols.h"
 
 namespace dart {
 
 DECLARE_FLAG(bool, print_ast);
@@ skipping 606 matching lines @@
       num_fixed_params + num_opt_pos_params + num_opt_named_params;
   ASSERT(function.NumParameters() == num_params);
   ASSERT(parsed_function().first_parameter_index() ==
          ParsedFunction::kFirstLocalSlotIndex);
 
   // Check that min_num_pos_args <= num_pos_args <= max_num_pos_args,
   // where num_pos_args is the number of positional arguments passed in.
   const int min_num_pos_args = num_fixed_params;
   const int max_num_pos_args = num_fixed_params + num_opt_pos_params;
 
-  // Number of positional args is the second Smi in descriptor array (R10).
-  __ movq(RCX, FieldAddress(R10, Array::data_offset() + (1 * kWordSize)));
+  __ movq(RCX,
+          FieldAddress(R10, ArgumentsDescriptor::positional_count_offset()));
   // Check that min_num_pos_args <= num_pos_args.
   Label wrong_num_arguments;
   __ cmpq(RCX, Immediate(Smi::RawValue(min_num_pos_args)));
   __ j(LESS, &wrong_num_arguments);
   // Check that num_pos_args <= max_num_pos_args.
   __ cmpq(RCX, Immediate(Smi::RawValue(max_num_pos_args)));
   __ j(GREATER, &wrong_num_arguments);
 
   // Copy positional arguments.
   // Argument i passed at fp[1 + num_args - i] is copied
   // to fp[ParsedFunction::kFirstLocalSlotIndex - i].
 
-  // Total number of args is the first Smi in args descriptor array (R10).
-  __ movq(RBX, FieldAddress(R10, Array::data_offset()));
+  __ movq(RBX, FieldAddress(R10, ArgumentsDescriptor::count_offset()));
   // Since RBX and RCX are Smi, use TIMES_4 instead of TIMES_8.
   // Let RBX point to the last passed positional argument, i.e. to
   // fp[1 + num_args - (num_pos_args - 1)].
   __ subq(RBX, RCX);
   __ leaq(RBX, Address(RBP, RBX, TIMES_4, 2 * kWordSize));
 
   // Let RDI point to the last copied positional argument, i.e. to
   // fp[ParsedFunction::kFirstLocalSlotIndex - (num_pos_args - 1)].
   const int index = ParsedFunction::kFirstLocalSlotIndex + 1;
   __ SmiUntag(RCX);
@@ skipping 33 matching lines @@
         const intptr_t result = opt_param_name.CompareTo(param_i->name());
         ASSERT(result != 0);
         if (result > 0) break;
         opt_param[i + 1] = opt_param[i];
         opt_param_position[i + 1] = opt_param_position[i];
       }
       opt_param[i + 1] = parameter;
       opt_param_position[i + 1] = pos;
     }
     // Generate code handling each optional parameter in alphabetical order.
-    // Total number of args is the first Smi in args descriptor array (R10).
-    __ movq(RBX, FieldAddress(R10, Array::data_offset()));
-    // Number of positional args is the second Smi in descriptor array (R10).
-    __ movq(RCX, FieldAddress(R10, Array::data_offset() + (1 * kWordSize)));
+    __ movq(RBX, FieldAddress(R10, ArgumentsDescriptor::count_offset()));
+    __ movq(RCX,
+            FieldAddress(R10, ArgumentsDescriptor::positional_count_offset()));
     __ SmiUntag(RCX);
     // Let RBX point to the first passed argument, i.e. to fp[1 + argc - 0].
     __ leaq(RBX, Address(RBP, RBX, TIMES_4, kWordSize));  // RBX is Smi.
-    // Let EDI point to the name/pos pair of the first named argument.
-    __ leaq(RDI, FieldAddress(R10, Array::data_offset() + (2 * kWordSize)));
+    // Let RDI point to the entry of the first named argument.
+    __ leaq(RDI,
+            FieldAddress(R10, ArgumentsDescriptor::first_named_entry_offset()));
     for (int i = 0; i < num_opt_named_params; i++) {
       Label load_default_value, assign_optional_parameter, next_parameter;
       const int param_pos = opt_param_position[i];
       // Check if this named parameter was passed in.
-      __ movq(RAX, Address(RDI, 0));  // Load RAX with the name of the argument.
+      // Load RAX with the name of the argument.
+      __ movq(RAX, Address(RDI, ArgumentsDescriptor::name_offset()));
       ASSERT(opt_param[i]->name().IsSymbol());
       __ CompareObject(RAX, opt_param[i]->name());
       __ j(NOT_EQUAL, &load_default_value, Assembler::kNearJump);
       // Load RAX with passed-in argument at provided arg_pos, i.e. at
       // fp[1 + argc - arg_pos].
-      __ movq(RAX, Address(RDI, kWordSize));  // RAX is arg_pos as Smi.
-      __ addq(RDI, Immediate(2 * kWordSize));  // Point to next name/pos pair.
+      __ movq(RAX, Address(RDI, ArgumentsDescriptor::position_offset()));
+      // RAX is arg_pos as Smi.
+      // Point to next named entry.
+      __ addq(RDI, Immediate(ArgumentsDescriptor::named_entry_size()));
       __ negq(RAX);
       Address argument_addr(RBX, RAX, TIMES_4, 0);  // RAX is a negative Smi.
       __ movq(RAX, argument_addr);
       __ jmp(&assign_optional_parameter, Assembler::kNearJump);
       __ Bind(&load_default_value);
       // Load RAX with default argument.
       const Object& value = Object::ZoneHandle(
           parsed_function().default_parameter_values().At(
               param_pos - num_fixed_params));
       __ LoadObject(RAX, value);
       __ Bind(&assign_optional_parameter);
       // Assign RAX to fp[ParsedFunction::kFirstLocalSlotIndex - param_pos].
       // We do not use the final allocation index of the variable here, i.e.
       // scope->VariableAt(i)->index(), because captured variables still need
       // to be copied to the context that is not yet allocated.
       const intptr_t computed_param_pos =
           ParsedFunction::kFirstLocalSlotIndex - param_pos;
       const Address param_addr(RBP, (computed_param_pos * kWordSize));
       __ movq(param_addr, RAX);
       __ Bind(&next_parameter);
     }
     delete[] opt_param;
     delete[] opt_param_position;
     // Check that RDI now points to the null terminator in the array descriptor.
     __ cmpq(Address(RDI, 0), raw_null);
     __ j(EQUAL, &all_arguments_processed, Assembler::kNearJump);
   } else {
     ASSERT(num_opt_pos_params > 0);
-    // Number of positional args is the second Smi in descriptor array (R10).
-    __ movq(RCX, FieldAddress(R10, Array::data_offset() + (1 * kWordSize)));
+    __ movq(RCX,
+            FieldAddress(R10, ArgumentsDescriptor::positional_count_offset()));
     __ SmiUntag(RCX);
     for (int i = 0; i < num_opt_pos_params; i++) {
       Label next_parameter;
       // Handle this optional positonal parameter only if k or fewer positional
       // arguments have been passed, where k is param_pos, the position of this
       // optional parameter in the formal parameter list.
       const int param_pos = num_fixed_params + i;
       __ cmpq(RCX, Immediate(param_pos));
       __ j(GREATER, &next_parameter, Assembler::kNearJump);
       // Load RAX with default argument.
       const Object& value = Object::ZoneHandle(
           parsed_function().default_parameter_values().At(i));
       __ LoadObject(RAX, value);
       // Assign RAX to fp[ParsedFunction::kFirstLocalSlotIndex - param_pos].
       // We do not use the final allocation index of the variable here, i.e.
       // scope->VariableAt(i)->index(), because captured variables still need
       // to be copied to the context that is not yet allocated.
       const intptr_t computed_param_pos =
           ParsedFunction::kFirstLocalSlotIndex - param_pos;
       const Address param_addr(RBP, (computed_param_pos * kWordSize));
       __ movq(param_addr, RAX);
       __ Bind(&next_parameter);
     }
-    // Total number of args is the first Smi in args descriptor array (R10).
-    __ movq(RBX, FieldAddress(R10, Array::data_offset()));
+    __ movq(RBX, FieldAddress(R10, ArgumentsDescriptor::count_offset()));
     __ SmiUntag(RBX);
     // Check that RCX equals RBX, i.e. no named arguments passed.
     __ cmpq(RCX, RBX);
     __ j(EQUAL, &all_arguments_processed, Assembler::kNearJump);
   }
 
   __ Bind(&wrong_num_arguments);
   if (StackSize() != 0) {
     // We need to unwind the space we reserved for locals and copied parameters.
     // The NoSuchMethodFunction stub does not expect to see that area on the
@@ skipping 30 matching lines @@
   __ ret();
 
   __ Bind(&all_arguments_processed);
   // Nullify originally passed arguments only after they have been copied and
   // checked, otherwise noSuchMethod would not see their original values.
   // This step can be skipped in case we decide that formal parameters are
   // implicitly final, since garbage collecting the unmodified value is not
   // an issue anymore.
 
   // R10 : arguments descriptor array.
-  // Total number of args is the first Smi in args descriptor array (R10).
-  __ movq(RCX, FieldAddress(R10, Array::data_offset()));
+  __ movq(RCX, FieldAddress(R10, ArgumentsDescriptor::count_offset()));
   __ SmiUntag(RCX);
   Label null_args_loop, null_args_loop_condition;
   __ jmp(&null_args_loop_condition, Assembler::kNearJump);
   const Address original_argument_addr(RBP, RCX, TIMES_8, 2 * kWordSize);
   __ Bind(&null_args_loop);
   __ movq(original_argument_addr, raw_null);
   __ Bind(&null_args_loop_condition);
   __ decq(RCX);
   __ j(POSITIVE, &null_args_loop, Assembler::kNearJump);
 }
@@ skipping 63 matching lines @@
 #ifdef DEBUG
     ASSERT(!parsed_function().function().HasOptionalParameters());
     const bool check_arguments = true;
 #else
     const bool check_arguments = function.IsClosureFunction();
 #endif
     if (check_arguments) {
       __ Comment("Check argument count");
       // Check that num_fixed <= argc <= num_params.
       Label argc_in_range;
-      // Total number of args is the first Smi in args descriptor array (R10).
-      __ movq(RAX, FieldAddress(R10, Array::data_offset()));
+      __ movq(RAX, FieldAddress(R10, ArgumentsDescriptor::count_offset()));
       __ cmpq(RAX, Immediate(Smi::RawValue(num_fixed_params)));
       __ j(EQUAL, &argc_in_range, Assembler::kNearJump);
       if (function.IsClosureFunction()) {
         if (StackSize() != 0) {
           // We need to unwind the space we reserved for locals and copied
           // parameters. The NoSuchMethodFunction stub does not expect to see
           // that area on the stack.
           __ addq(RSP, Immediate(StackSize() * kWordSize));
         }
         // The call below has an empty stackmap because we have just
@@ skipping 479 matching lines @@
 void ParallelMoveResolver::Exchange(const Address& mem1, const Address& mem2) {
   __ Exchange(mem1, mem2);
 }
 
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64