[scudo] Remove false DCHECK

[vitalybuka]

Summary

MTE Cache.store passes MAP_NOACCESS here.

[vitalybuka]

rebase

[pcc]

LGTM

[vitalybuka]

rebase

[vitalybuka]

fix rebase

compiler-rt/lib/scudo/standalone/linux.cpp

void *map(void *Addr, uptr Size, UNUSED const char *Name, uptr Flags,
   }
 #if defined(__aarch64__)
 #ifndef PROT_MTE
 #define PROT_MTE 0x20
 #endif
   if (Flags & MAP_MEMTAG)
     MmapProt |= PROT_MTE;
 #endif
-  if (Addr) {
-    // Currently no scenario for a noaccess mapping with a fixed address.
-    DCHECK_EQ(Flags & MAP_NOACCESS, 0);
+  if (Addr)
     MmapFlags |= MAP_FIXED;
-  }
   void *P = mmap(Addr, Size, MmapProt, MmapFlags, -1, 0);
   if (P == MAP_FAILED) {
     if (!(Flags & MAP_ALLOWNOMEM) || errno != ENOMEM)
       dieOnMapUnmapError(errno == ENOMEM ? Size : 0);
     return nullptr;
   }
 #if SCUDO_ANDROID
   if (Name)

compiler-rt/lib/scudo/standalone/tests/secondary_test.cpp

 //===-- secondary_test.cpp --------------------------------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
+#include "memtag.h"
 #include "tests/scudo_unit_test.h"
 
 #include "allocator_config.h"
 #include "secondary.h"
 
 #include <condition_variable>
 #include <memory>
 #include <mutex>
 #include <random>
 #include <stdio.h>
 #include <thread>
 #include <vector>
 
 template <typename Config> static scudo::Options getOptionsForConfig() {
+  if (!Config::MaySupportMemoryTagging || !scudo::archSupportsMemoryTagging())
     return {};
+  scudo::AtomicOptions AO;
+  AO.set(scudo::OptionBit::UseMemoryTagging);
+  return AO.load();
 }
 
 template <typename Config> static void testSecondaryBasic(void) {
   using SecondaryT = scudo::MapAllocator<Config>;
   scudo::Options Options = getOptionsForConfig<Config>();
 
   scudo::GlobalStats S;
   S.init();