Remove unused/not working function tracing flag and functionality.

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/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);
 DECLARE_FLAG(bool, print_scopes);
-DECLARE_FLAG(bool, trace_functions);
 DECLARE_FLAG(bool, use_sse41);
 DEFINE_FLAG(bool, trap_on_deoptimization, false, "Trap on deoptimization.");
 
 
 FieldAddress FlowGraphCompiler::ElementAddressForRegIndex(intptr_t cid,
                                                           Register array,
                                                           Register index) {
   // Note that index is Smi, i.e, times 2.
   ASSERT(kSmiTagShift == 1);
   switch (cid) {
@@ skipping 794 matching lines @@
     // RBX : ic-data.
     // R10 : arguments descriptor array.
     __ call(&StubCode::CallNoSuchMethodFunctionLabel());
   }
   if (is_optimizing()) {
     stackmap_table_builder_->AddEntry(assembler()->CodeSize(),
                                       empty_stack_bitmap,
                                       0);  // No registers.
   }
 
-  if (FLAG_trace_functions) {
-    __ pushq(RAX);  // Preserve result.
-    __ PushObject(Function::ZoneHandle(function.raw()));
-    // We do not use GenerateCallRuntime because of the non-standard (empty)
-    // stackmap used here.
-    __ CallRuntime(kTraceFunctionExitRuntimeEntry);
-    AddCurrentDescriptor(PcDescriptors::kOther,
-                         Isolate::kNoDeoptId,
-                         0);  // No token position.
-    if (is_optimizing()) {
-      stackmap_table_builder_->AddEntry(assembler()->CodeSize(),
-                                        empty_stack_bitmap,
-                                        0);  // No registers.
-    }
-    __ popq(RAX);  // Remove argument.
-    __ popq(RAX);  // Restore result.
-  }
   __ LeaveFrame();
   __ 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.
 
@@ skipping 490 matching lines @@
 void ParallelMoveResolver::Exchange(const Address& mem1, const Address& mem2) {
   __ Exchange(mem1, mem2);
 }
 
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64