Cache current thread in a reserved register and use it in LoadIsolate

runtime/vm/flow_graph_compiler_arm.cc

 // Copyright (c) 2013, 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_ARM.
 #if defined(TARGET_ARCH_ARM)
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/ast_printer.h"
@@ skipping 746 matching lines @@
   const int num_params =
       num_fixed_params + num_opt_pos_params + num_opt_named_params;
   ASSERT(function.NumParameters() == num_params);
   ASSERT(parsed_function().first_parameter_index() == kFirstLocalSlotFromFp);
 
   // 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;
 
-  __ ldr(R8, FieldAddress(R4, ArgumentsDescriptor::positional_count_offset()));
+  __ ldr(R9, FieldAddress(R4, ArgumentsDescriptor::positional_count_offset()));
   // Check that min_num_pos_args <= num_pos_args.
   Label wrong_num_arguments;
-  __ CompareImmediate(R8, Smi::RawValue(min_num_pos_args));
+  __ CompareImmediate(R9, Smi::RawValue(min_num_pos_args));
   __ b(&wrong_num_arguments, LT);
   // Check that num_pos_args <= max_num_pos_args.
-  __ CompareImmediate(R8, Smi::RawValue(max_num_pos_args));
+  __ CompareImmediate(R9, Smi::RawValue(max_num_pos_args));
   __ b(&wrong_num_arguments, GT);
 
   // Copy positional arguments.
   // Argument i passed at fp[kParamEndSlotFromFp + num_args - i] is copied
   // to fp[kFirstLocalSlotFromFp - i].
 
   __ ldr(R7, FieldAddress(R4, ArgumentsDescriptor::count_offset()));
-  // Since R7 and R8 are Smi, use LSL 1 instead of LSL 2.
+  // Since R7 and R9 are Smi, use LSL 1 instead of LSL 2.
   // Let R7 point to the last passed positional argument, i.e. to
   // fp[kParamEndSlotFromFp + num_args - (num_pos_args - 1)].
-  __ sub(R7, R7, Operand(R8));
+  __ sub(R7, R7, Operand(R9));
   __ add(R7, FP, Operand(R7, LSL, 1));
   __ add(R7, R7, Operand((kParamEndSlotFromFp + 1) * kWordSize));
 
   // Let R6 point to the last copied positional argument, i.e. to
   // fp[kFirstLocalSlotFromFp - (num_pos_args - 1)].
   __ AddImmediate(R6, FP, (kFirstLocalSlotFromFp + 1) * kWordSize);
-  __ sub(R6, R6, Operand(R8, LSL, 1));  // R8 is a Smi.
-  __ SmiUntag(R8);
+  __ sub(R6, R6, Operand(R9, LSL, 1));  // R9 is a Smi.
+  __ SmiUntag(R9);
   Label loop, loop_condition;
   __ b(&loop_condition);
   // 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 Address argument_addr(R7, R8, LSL, 2);
-  const Address copy_addr(R6, R8, LSL, 2);
+  const Address argument_addr(R7, R9, LSL, 2);
+  const Address copy_addr(R6, R9, LSL, 2);
   __ Bind(&loop);
   __ ldr(IP, argument_addr);
   __ str(IP, copy_addr);
   __ Bind(&loop_condition);
-  __ subs(R8, R8, Operand(1));
+  __ subs(R9, R9, Operand(1));
   __ b(&loop, PL);
 
   // Copy or initialize optional named arguments.
   Label all_arguments_processed;
 #ifdef DEBUG
     const bool check_correct_named_args = true;
 #else
     const bool check_correct_named_args = function.IsClosureFunction();
 #endif
   if (num_opt_named_params > 0) {
@@ skipping 10 matching lines @@
         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.
     __ ldr(R7, FieldAddress(R4, ArgumentsDescriptor::count_offset()));
-    __ ldr(R8,
+    __ ldr(R9,
            FieldAddress(R4, ArgumentsDescriptor::positional_count_offset()));
-    __ SmiUntag(R8);
+    __ SmiUntag(R9);
     // Let R7 point to the first passed argument, i.e. to
     // fp[kParamEndSlotFromFp + num_args - 0]; num_args (R7) is Smi.
     __ add(R7, FP, Operand(R7, LSL, 1));
     __ AddImmediate(R7, R7, kParamEndSlotFromFp * kWordSize);
     // Let R6 point to the entry of the first named argument.
     __ add(R6, R4, Operand(
         ArgumentsDescriptor::first_named_entry_offset() - kHeapObjectTag));
     for (int i = 0; i < num_opt_named_params; i++) {
       Label load_default_value, assign_optional_parameter;
       const int param_pos = opt_param_position[i];
@@ skipping 32 matching lines @@
     delete[] opt_param_position;
     if (check_correct_named_args) {
       // Check that R6 now points to the null terminator in the arguments
       // descriptor.
       __ ldr(R5, Address(R6, 0));
       __ CompareImmediate(R5, reinterpret_cast<int32_t>(Object::null()));
       __ b(&all_arguments_processed, EQ);
     }
   } else {
     ASSERT(num_opt_pos_params > 0);
-    __ ldr(R8,
+    __ ldr(R9,
            FieldAddress(R4, ArgumentsDescriptor::positional_count_offset()));
-    __ SmiUntag(R8);
+    __ SmiUntag(R9);
     for (int i = 0; i < num_opt_pos_params; i++) {
       Label next_parameter;
       // Handle this optional positional 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;
-      __ CompareImmediate(R8, param_pos);
+      __ CompareImmediate(R9, param_pos);
       __ b(&next_parameter, GT);
       // Load R5 with default argument.
       const Object& value = Object::ZoneHandle(
           parsed_function().default_parameter_values().At(i));
       __ LoadObject(R5, value);
       // Assign R5 to fp[kFirstLocalSlotFromFp - 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 = kFirstLocalSlotFromFp - param_pos;
       const Address param_addr(FP, computed_param_pos * kWordSize);
       __ str(R5, param_addr);
       __ Bind(&next_parameter);
     }
     if (check_correct_named_args) {
       __ ldr(R7, FieldAddress(R4, ArgumentsDescriptor::count_offset()));
       __ SmiUntag(R7);
-      // Check that R8 equals R7, i.e. no named arguments passed.
-      __ cmp(R8, Operand(R7));
+      // Check that R9 equals R7, i.e. no named arguments passed.
+      __ cmp(R9, Operand(R7));
       __ b(&all_arguments_processed, EQ);
     }
   }
 
   __ Bind(&wrong_num_arguments);
   if (function.IsClosureFunction()) {
     __ LeaveDartFrame();  // The arguments are still on the stack.
     __ Branch(&isolate()->stub_code()->CallClosureNoSuchMethodLabel());
     // The noSuchMethod call may return to the caller, but not here.
   } else if (check_correct_named_args) {
     __ Stop("Wrong arguments");
   }
 
   __ 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.
 
   // R4 : arguments descriptor array.
-  __ ldr(R8, FieldAddress(R4, ArgumentsDescriptor::count_offset()));
-  __ SmiUntag(R8);
+  __ ldr(R9, FieldAddress(R4, ArgumentsDescriptor::count_offset()));
+  __ SmiUntag(R9);
   __ add(R7, FP, Operand((kParamEndSlotFromFp + 1) * kWordSize));
-  const Address original_argument_addr(R7, R8, LSL, 2);
+  const Address original_argument_addr(R7, R9, LSL, 2);
   __ LoadImmediate(IP, reinterpret_cast<intptr_t>(Object::null()));
   Label null_args_loop, null_args_loop_condition;
   __ b(&null_args_loop_condition);
   __ Bind(&null_args_loop);
   __ str(IP, original_argument_addr);
   __ Bind(&null_args_loop_condition);
-  __ subs(R8, R8, Operand(1));
+  __ subs(R9, R9, Operand(1));
   __ b(&null_args_loop, PL);
 }
 
 
 void FlowGraphCompiler::GenerateInlinedGetter(intptr_t offset) {
   // LR: return address.
   // SP: receiver.
   // Sequence node has one return node, its input is load field node.
   __ Comment("Inlined Getter");
   __ ldr(R0, Address(SP, 0 * kWordSize));
@@ skipping 896 matching lines @@
   DRegister dreg = EvenDRegisterOf(reg);
   __ vldrd(dreg, Address(SP, kDoubleSize, Address::PostIndex));
 }
 
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM