[gardening] Always tag class_id register on arm64 in subtype test cac…

…he stub LoadClassById no longer tags class_id register as side-effect. This change was missing for arm64 in ef9d699. Change-Id: I92278b01ec2211dc9be860c1a5386ecd4253fb0e Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/116526 Reviewed-by: Martin Kustermann <kustermann@google.com> Commit-Queue: Martin Kustermann <kustermann@google.com>
aam · Sep 10, 2019 · 300c333 · 300c333
1 parent 6717bfe
commit 300c333
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Showing 5 changed files with 5 additions and 10 deletions.
diff --git a/runtime/vm/compiler/asm_intrinsifier_arm.cc b/runtime/vm/compiler/asm_intrinsifier_arm.cc
@@ -1607,7 +1607,7 @@ void AsmIntrinsifier::ObjectRuntimeType(Assembler* assembler,
   __ Ret();
 
   __ Bind(&use_declaration_type);
-  __ LoadClassById(R2, R1);  // Overwrites R1.
+  __ LoadClassById(R2, R1);
   __ ldrh(R3, FieldAddress(R2, target::Class::num_type_arguments_offset()));
   __ CompareImmediate(R3, 0);
   __ b(normal_ir_body, NE);

diff --git a/runtime/vm/compiler/asm_intrinsifier_arm64.cc b/runtime/vm/compiler/asm_intrinsifier_arm64.cc
@@ -1668,7 +1668,7 @@ void AsmIntrinsifier::ObjectRuntimeType(Assembler* assembler,
   __ ret();
 
   __ Bind(&use_declaration_type);
-  __ LoadClassById(R2, R1);  // Overwrites R1.
+  __ LoadClassById(R2, R1);
   __ ldr(R3, FieldAddress(R2, target::Class::num_type_arguments_offset()),
          kHalfword);
   __ CompareImmediate(R3, 0);
@@ -1704,7 +1704,7 @@ void AsmIntrinsifier::ObjectHaveSameRuntimeType(Assembler* assembler,
   // Objects have the same class and neither is a closure.
   // Check if there are no type arguments. In this case we can return true.
   // Otherwise fall through into the runtime to handle comparison.
-  __ LoadClassById(R3, R1);  // Overwrites R1.
+  __ LoadClassById(R3, R1);
   __ ldr(R3, FieldAddress(R3, target::Class::num_type_arguments_offset()),
          kHalfword);
   __ CompareImmediate(R3, 0);

diff --git a/runtime/vm/compiler/assembler/assembler_arm64.h b/runtime/vm/compiler/assembler/assembler_arm64.h
@@ -1526,7 +1526,6 @@ class Assembler : public AssemblerBase {
   void CompareObject(Register reg, const Object& object);
 
   void LoadClassId(Register result, Register object);
-  // Overwrites class_id register (it will be tagged afterwards).
   void LoadClassById(Register result, Register class_id);
   void CompareClassId(Register object,
                       intptr_t class_id,

diff --git a/runtime/vm/compiler/assembler/assembler_x64.h b/runtime/vm/compiler/assembler/assembler_x64.h
@@ -803,7 +803,6 @@ class Assembler : public AssemblerBase {
 
   // Loading and comparing classes of objects.
   void LoadClassId(Register result, Register object);
-
   void LoadClassById(Register result, Register class_id);
 
   void CompareClassId(Register object,

diff --git a/runtime/vm/compiler/stub_code_compiler_arm64.cc b/runtime/vm/compiler/stub_code_compiler_arm64.cc
@@ -2796,12 +2796,8 @@ static void GenerateSubtypeNTestCacheStub(Assembler* assembler, int n) {
   // Non-Closure handling.
   {
     __ Bind(&not_closure);
-    if (n == 1) {
-      __ SmiTag(kInstanceCidOrFunction);
-    } else {
-      ASSERT(n >= 2);
+    if (n >= 2) {
       Label has_no_type_arguments;
-      // [LoadClassById] also tags [kInstanceCidOrFunction] as a side-effect.
       __ LoadClassById(R5, kInstanceCidOrFunction);
       __ mov(kInstanceInstantiatorTypeArgumentsReg, kNullReg);
       __ LoadFieldFromOffset(
@@ -2818,6 +2814,7 @@ static void GenerateSubtypeNTestCacheStub(Assembler* assembler, int n) {
         __ mov(kInstanceDelayedFunctionTypeArgumentsReg, kNullReg);
       }
     }
+    __ SmiTag(kInstanceCidOrFunction);
   }
 
   Label found, not_found, next_iteration;