Provide a tagged allocation top pointer.

test/cctest/test-macro-assembler-mips64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 12 matching lines @@
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include <stdlib.h>
 #include <iostream>  // NOLINT(readability/streams)
 
 #include "src/v8.h"
 #include "test/cctest/cctest.h"
+#include "test/cctest/heap/heap-utils.h"
 
 #include "src/base/utils/random-number-generator.h"
 #include "src/macro-assembler.h"
 #include "src/mips64/macro-assembler-mips64.h"
 #include "src/mips64/simulator-mips64.h"
 
 
 using namespace v8::internal;
 
 typedef void* (*F)(int64_t x, int64_t y, int p2, int p3, int p4);
@@ skipping 1695 matching lines @@
                            [](MacroAssembler* masm, int32_t in_offset,
                               int32_t out_offset) {
                              __ Uldc1(f0, MemOperand(a0, in_offset), t0);
                              __ Usdc1(f0, MemOperand(a0, out_offset), t0);
                            }));
       }
     }
   }
 }
 
+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);
+  __ jr(ra);
+
+  CodeDesc desc;
+  masm->GetCode(&desc);
+}
+
+TEST(AllocateMacrosNoGCRequired) {
+  typedef intptr_t (*F0)();
+  // Allocate an executable page of memory.
+  CcTest::InitializeVM();
+  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 kNoAllocationFlags =
+      static_cast<AllocationFlags>(NO_ALLOCATION_FLAGS);
+
+#define CHECK_TAGGED(result) CHECK_EQ(result& kHeapObjectTag, 1);
+
+  heap::GcAndSweep(isolate->heap(), AllocationSpace::NEW_SPACE);
+  {
+    AssembleFunction(isolate, actual_size, buffer, [](MacroAssembler* masm) {
+      Label gc_required, success;
+      __ Allocate(kPointerSize, v0, t0, t1, &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;
+      __ li(a0, Operand(kPointerSize));
+      __ Allocate(a0, v0, t0, t1, &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);
+  }
+
+#undef CHECK_TAGGED
+}
+
 #undef __