Revert "Revert "ART: Reference.getReferent intrinsic for x86 and x86_64""

This reverts commit 0997d24e67d78f2146ebae2888eda0d7d254789a.

ART_HEAP_POISONING=true mode is fixed.

Change-Id: I83f6d5c101ea6a86802753f81b3e4348a263fb21
Signed-off-by: Serguei Katkov <serguei.i.katkov@intel.com>
diff --git a/compiler/optimizing/code_generator_x86.cc b/compiler/optimizing/code_generator_x86.cc
index 50892a9..bdbafcd 100644
--- a/compiler/optimizing/code_generator_x86.cc
+++ b/compiler/optimizing/code_generator_x86.cc
@@ -4308,16 +4308,18 @@
   // save one load. However, since this is just an intrinsic slow path we prefer this
   // simple and more robust approach rather that trying to determine if that's the case.
   SlowPathCode* slow_path = GetCurrentSlowPath();
-  DCHECK(slow_path != nullptr);  // For intrinsified invokes the call is emitted on the slow path.
-  if (slow_path->IsCoreRegisterSaved(location.AsRegister<Register>())) {
-    int stack_offset = slow_path->GetStackOffsetOfCoreRegister(location.AsRegister<Register>());
-    __ movl(temp, Address(ESP, stack_offset));
-    return temp;
+  if (slow_path != nullptr) {
+    if (slow_path->IsCoreRegisterSaved(location.AsRegister<Register>())) {
+      int stack_offset = slow_path->GetStackOffsetOfCoreRegister(location.AsRegister<Register>());
+      __ movl(temp, Address(ESP, stack_offset));
+      return temp;
+    }
   }
   return location.AsRegister<Register>();
 }
 
-void CodeGeneratorX86::GenerateStaticOrDirectCall(HInvokeStaticOrDirect* invoke, Location temp) {
+Location CodeGeneratorX86::GenerateCalleeMethodStaticOrDirectCall(HInvokeStaticOrDirect* invoke,
+                                                                  Location temp) {
   Location callee_method = temp;  // For all kinds except kRecursive, callee will be in temp.
   switch (invoke->GetMethodLoadKind()) {
     case HInvokeStaticOrDirect::MethodLoadKind::kStringInit:
@@ -4366,6 +4368,11 @@
       break;
     }
   }
+  return callee_method;
+}
+
+void CodeGeneratorX86::GenerateStaticOrDirectCall(HInvokeStaticOrDirect* invoke, Location temp) {
+  Location callee_method = GenerateCalleeMethodStaticOrDirectCall(invoke, temp);
 
   switch (invoke->GetCodePtrLocation()) {
     case HInvokeStaticOrDirect::CodePtrLocation::kCallSelf: