Provide a tagged allocation top pointer.

test/cctest/test-macro-assembler-arm.cc

Index: test/cctest/test-macro-assembler-arm.cc
diff --git a/test/cctest/test-macro-assembler-arm.cc b/test/cctest/test-macro-assembler-arm.cc
index 24ab60e972e1b7718c4d12abd23504f3bc38ed6a..0d05102a83c8068d42728bd7c4ff4e66ea017f5a 100644
--- a/test/cctest/test-macro-assembler-arm.cc
+++ b/test/cctest/test-macro-assembler-arm.cc
@@ -29,6 +29,7 @@
 
 #include "src/v8.h"
 #include "test/cctest/cctest.h"
+#include "test/cctest/heap/heap-utils.h"
 
 #include "src/macro-assembler.h"
 
@@ -226,4 +227,112 @@ TEST(LoadAndStoreWithRepresentation) {
   CHECK(!CALL_GENERATED_CODE(isolate, f, 0, 0, 0, 0, 0));
 }
 
+template <typename Fun>
+void AssembleFunction(Isolate* isolate, size_t actual_size, byte* buffer,
+                      Fun f) {
+  MacroAssembler assembler(isolate, buffer, static_cast<int>(actual_size),
+                           v8::internal::CodeObjectRequired::kYes);
+  MacroAssembler* masm = &assembler;
+  f(masm);
+  __ bx(lr);
+
+  CodeDesc desc;
+  masm->GetCode(&desc);
+}
+
+TEST(AllocateMacrosNoGCRequired) {
+  typedef intptr_t (*F0)();
+
+  // Allocate an executable page of memory.
+  size_t actual_size;
+  byte* buffer = static_cast<byte*>(v8::base::OS::Allocate(
+      Assembler::kMinimalBufferSize, &actual_size, true));
+  CHECK(buffer);
+  Isolate* isolate = CcTest::i_isolate();
+  HandleScope handles(isolate);
+
+  AllocationFlags const kDoubleAligned =
+      static_cast<AllocationFlags>(DOUBLE_ALIGNMENT);
+  AllocationFlags const kNoAllocationFlags =
+      static_cast<AllocationFlags>(NO_ALLOCATION_FLAGS);
+
+#define CHECK_TAGGED(result) CHECK_EQ(result& kHeapObjectTag, 1);
+#define CHECK_DOUBLE_ALIGNED(result)                                   \
+  do {                                                                 \
+    CHECK_TAGGED((result));                                            \
+    CHECK_EQ((result)&kDoubleAlignmentMaskTagged, 0);                  \
+    /* Check that the filler was written in the correct place */       \
+    CHECK_EQ(*reinterpret_cast<v8::internal::Map***>(                  \
+                 (result) - (kHeapObjectTag + kPointerSize)),          \
+             isolate->factory()->one_pointer_filler_map().location()); \
+  } while (false)
+
+  heap::GcAndSweep(isolate->heap(), AllocationSpace::NEW_SPACE);
+  {
+    AssembleFunction(isolate, actual_size, buffer, [](MacroAssembler* masm) {
+      Label gc_required, success;
+      __ Allocate(kPointerSize, r0, r1, r2, &gc_required, kNoAllocationFlags);
+      __ jmp(&success);
+      __ bind(&gc_required);
+      __ Abort(kNoReason);
+      __ bind(&success);
+    });
+    F0 f = FUNCTION_CAST<F0>(buffer);
+    intptr_t test_result = reinterpret_cast<intptr_t>(
+        CALL_GENERATED_CODE(isolate, f, 0, 0, 0, 0, 0));
+    CHECK_TAGGED(test_result);
+  }
+
+  {
+    AssembleFunction(isolate, actual_size, buffer, [](MacroAssembler* masm) {
+      Label gc_required, success;
+      __ Allocate(kDoubleSize, r0, r1, r2, &gc_required, kDoubleAligned);
+      __ jmp(&success);
+      __ bind(&gc_required);
+      __ Abort(kNoReason);
+      __ bind(&success);
+    });
+    heap::MakeSureNewSpaceTopIsNotDoubleAligned(isolate->heap());
+    F0 f = FUNCTION_CAST<F0>(buffer);
+    intptr_t test_result = reinterpret_cast<intptr_t>(
+        CALL_GENERATED_CODE(isolate, f, 0, 0, 0, 0, 0));
+    CHECK_DOUBLE_ALIGNED(test_result);
+  }
+  {
+    AssembleFunction(isolate, actual_size, buffer, [](MacroAssembler* masm) {
+      Label gc_required, success;
+      __ mov(r3, Operand(kPointerSize));
+      __ Allocate(r3, r0, r1, r2, &gc_required, kNoAllocationFlags);
+      __ jmp(&success);
+      __ bind(&gc_required);
+      __ Abort(kNoReason);
+      __ bind(&success);
+    });
+    F0 f = FUNCTION_CAST<F0>(buffer);
+    intptr_t test_result = reinterpret_cast<intptr_t>(
+        CALL_GENERATED_CODE(isolate, f, 0, 0, 0, 0, 0));
+    CHECK_TAGGED(test_result);
+  }
+
+  {
+    AssembleFunction(isolate, actual_size, buffer, [](MacroAssembler* masm) {
+      Label gc_required, success;
+      __ mov(r3, Operand(kDoubleSize));
+      __ Allocate(r3, r0, r1, r2, &gc_required, kDoubleAligned);
+      __ jmp(&success);
+      __ bind(&gc_required);
+      __ Abort(kNoReason);
+      __ bind(&success);
+    });
+    heap::MakeSureNewSpaceTopIsNotDoubleAligned(isolate->heap());
+    F0 f = FUNCTION_CAST<F0>(buffer);
+    intptr_t test_result = reinterpret_cast<intptr_t>(
+        CALL_GENERATED_CODE(isolate, f, 0, 0, 0, 0, 0));
+    CHECK_DOUBLE_ALIGNED(test_result);
+  }
+
+#undef CHECK_TAGGED
+#undef CHECK_DOUBLE_ALIGNED
+}
+
 #undef __