Fix x86-64 Baker's read barrier fast path for CheckCast.
Use an art::x86_64::Label instead of an
art::x86_64::NearLabel as end label when emitting code for a
HCheckCast instruction, as the range of the latter may
sometimes be too short when Baker's read barriers are
enabled.
Bug: 12687968
Change-Id: Ia9742dce65be7d4fb104688f3c4717b65df1fb54
diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index 99396cd..4f0f5f0 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -5840,19 +5840,20 @@
is_type_check_slow_path_fatal);
codegen_->AddSlowPath(type_check_slow_path);
- NearLabel done;
- // Avoid null check if we know obj is not null.
- if (instruction->MustDoNullCheck()) {
- __ testl(obj, obj);
- __ j(kEqual, &done);
- }
-
- // /* HeapReference<Class> */ temp = obj->klass_
- GenerateReferenceLoadTwoRegisters(instruction, temp_loc, obj_loc, class_offset, maybe_temp2_loc);
-
switch (type_check_kind) {
case TypeCheckKind::kExactCheck:
case TypeCheckKind::kArrayCheck: {
+ NearLabel done;
+ // Avoid null check if we know obj is not null.
+ if (instruction->MustDoNullCheck()) {
+ __ testl(obj, obj);
+ __ j(kEqual, &done);
+ }
+
+ // /* HeapReference<Class> */ temp = obj->klass_
+ GenerateReferenceLoadTwoRegisters(
+ instruction, temp_loc, obj_loc, class_offset, maybe_temp2_loc);
+
if (cls.IsRegister()) {
__ cmpl(temp, cls.AsRegister<CpuRegister>());
} else {
@@ -5862,10 +5863,22 @@
// Jump to slow path for throwing the exception or doing a
// more involved array check.
__ j(kNotEqual, type_check_slow_path->GetEntryLabel());
+ __ Bind(&done);
break;
}
case TypeCheckKind::kAbstractClassCheck: {
+ NearLabel done;
+ // Avoid null check if we know obj is not null.
+ if (instruction->MustDoNullCheck()) {
+ __ testl(obj, obj);
+ __ j(kEqual, &done);
+ }
+
+ // /* HeapReference<Class> */ temp = obj->klass_
+ GenerateReferenceLoadTwoRegisters(
+ instruction, temp_loc, obj_loc, class_offset, maybe_temp2_loc);
+
// If the class is abstract, we eagerly fetch the super class of the
// object to avoid doing a comparison we know will fail.
NearLabel loop, compare_classes;
@@ -5896,10 +5909,22 @@
__ cmpl(temp, Address(CpuRegister(RSP), cls.GetStackIndex()));
}
__ j(kNotEqual, &loop);
+ __ Bind(&done);
break;
}
case TypeCheckKind::kClassHierarchyCheck: {
+ NearLabel done;
+ // Avoid null check if we know obj is not null.
+ if (instruction->MustDoNullCheck()) {
+ __ testl(obj, obj);
+ __ j(kEqual, &done);
+ }
+
+ // /* HeapReference<Class> */ temp = obj->klass_
+ GenerateReferenceLoadTwoRegisters(
+ instruction, temp_loc, obj_loc, class_offset, maybe_temp2_loc);
+
// Walk over the class hierarchy to find a match.
NearLabel loop;
__ Bind(&loop);
@@ -5927,10 +5952,26 @@
GenerateReferenceLoadTwoRegisters(
instruction, temp_loc, obj_loc, class_offset, maybe_temp2_loc);
__ jmp(type_check_slow_path->GetEntryLabel());
+ __ Bind(&done);
break;
}
case TypeCheckKind::kArrayObjectCheck: {
+ // We cannot use a NearLabel here, as its range might be too
+ // short in some cases when read barriers are enabled. This has
+ // been observed for instance when the code emitted for this
+ // case uses high x86-64 registers (R8-R15).
+ Label done;
+ // Avoid null check if we know obj is not null.
+ if (instruction->MustDoNullCheck()) {
+ __ testl(obj, obj);
+ __ j(kEqual, &done);
+ }
+
+ // /* HeapReference<Class> */ temp = obj->klass_
+ GenerateReferenceLoadTwoRegisters(
+ instruction, temp_loc, obj_loc, class_offset, maybe_temp2_loc);
+
// Do an exact check.
NearLabel check_non_primitive_component_type;
if (cls.IsRegister()) {
@@ -5969,11 +6010,23 @@
GenerateReferenceLoadTwoRegisters(
instruction, temp_loc, obj_loc, class_offset, maybe_temp2_loc);
__ jmp(type_check_slow_path->GetEntryLabel());
+ __ Bind(&done);
break;
}
case TypeCheckKind::kUnresolvedCheck:
case TypeCheckKind::kInterfaceCheck:
+ NearLabel done;
+ // Avoid null check if we know obj is not null.
+ if (instruction->MustDoNullCheck()) {
+ __ testl(obj, obj);
+ __ j(kEqual, &done);
+ }
+
+ // /* HeapReference<Class> */ temp = obj->klass_
+ GenerateReferenceLoadTwoRegisters(
+ instruction, temp_loc, obj_loc, class_offset, maybe_temp2_loc);
+
// We always go into the type check slow path for the unresolved
// and interface check cases.
//
@@ -5992,9 +6045,9 @@
// call to the runtime not using a type checking slow path).
// This should also be beneficial for the other cases above.
__ jmp(type_check_slow_path->GetEntryLabel());
+ __ Bind(&done);
break;
}
- __ Bind(&done);
__ Bind(type_check_slow_path->GetExitLabel());
}