Setup R10/EDX to be valid Oops before stub calls

runtime/vm/flow_graph_compiler_arm64.cc

 // Copyright (c) 2014, 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_ARM64.
 #if defined(TARGET_ARCH_ARM64)
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/ast_printer.h"
@@ skipping 1197 matching lines @@
 }
 
 
 void FlowGraphCompiler::EmitInstanceCall(ExternalLabel* target_label,
                                          const ICData& ic_data,
                                          intptr_t argument_count,
                                          intptr_t deopt_id,
                                          intptr_t token_pos,
                                          LocationSummary* locs) {
   ASSERT(Array::Handle(ic_data.arguments_descriptor()).Length() > 0);
+  __ LoadImmediate(R4, 0, kNoPP);
   __ LoadObject(R5, ic_data, PP);
   GenerateDartCall(deopt_id,
                    token_pos,
                    target_label,
                    PcDescriptors::kIcCall,
                    locs);
   __ Drop(argument_count);
+#if defined(DEBUG)
+  __ LoadImmediate(R4, 1, kNoPP);  // Garbage that looks like an object.
+#endif
 }
 
 
 void FlowGraphCompiler::EmitMegamorphicInstanceCall(
     const ICData& ic_data,
     intptr_t argument_count,
     intptr_t deopt_id,
     intptr_t token_pos,
     LocationSummary* locs) {
   MegamorphicCacheTable* table = Isolate::Current()->megamorphic_cache_table();
@@ skipping 59 matching lines @@
     const ICData& ic_data) {
   uword label_address = 0;
   if (ic_data.NumArgsTested() == 0) {
     label_address = StubCode::ZeroArgsUnoptimizedStaticCallEntryPoint();
   } else if (ic_data.NumArgsTested() == 2) {
     label_address = StubCode::TwoArgsUnoptimizedStaticCallEntryPoint();
   } else {
     UNIMPLEMENTED();
   }
   ExternalLabel target_label(label_address);
+  __ LoadImmediate(R4, 0, kNoPP);
   __ LoadObject(R5, ic_data, PP);
   GenerateDartCall(deopt_id,
                    token_pos,
                    &target_label,
                    PcDescriptors::kUnoptStaticCall,
                    locs);
+#if defined(DEBUG)
+  __ LoadImmediate(R5, 1, kNoPP);  // Garbage that looks like an object.
+#endif
   __ Drop(argument_count);
 }
 
 
 void FlowGraphCompiler::EmitOptimizedStaticCall(
     const Function& function,
     const Array& arguments_descriptor,
     intptr_t argument_count,
     intptr_t deopt_id,
     intptr_t token_pos,
@@ skipping 44 matching lines @@
                                                   Register right,
                                                   bool needs_number_check,
                                                   intptr_t token_pos) {
   if (needs_number_check) {
     __ Push(left);
     __ Push(right);
     if (is_optimizing()) {
       __ BranchLinkPatchable(
           &StubCode::OptimizedIdenticalWithNumberCheckLabel());
     } else {
+      __ LoadImmediate(R4, 0, kNoPP);
+      __ LoadImmediate(R5, 0, kNoPP);
       __ BranchLinkPatchable(
           &StubCode::UnoptimizedIdenticalWithNumberCheckLabel());
     }
     if (token_pos != Scanner::kNoSourcePos) {
       AddCurrentDescriptor(PcDescriptors::kRuntimeCall,
                            Isolate::kNoDeoptId,
                            token_pos);
     }
+#if defined(DEBUG)
+    if (!is_optimizing()) {
+      // Do this *after* adding the pc descriptor!
+      __ LoadImmediate(R4, 1, kNoPP);  // Garbage that looks like an object.
+      __ LoadImmediate(R5, 1, kNoPP);
+    }
+#endif
     // Stub returns result in flags (result of a cmpl, we need ZF computed).
     __ Pop(right);
     __ Pop(left);
   } else {
     __ CompareRegisters(left, right);
   }
 }
 
 
 // This function must be in sync with FlowGraphCompiler::RecordSafepoint and
@@ skipping 317 matching lines @@
 void ParallelMoveResolver::RestoreFpuScratch(FpuRegister reg) {
   UNIMPLEMENTED();
 }
 
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64