[sanitizer] Move the errno/ENOMEM allocator checks logic to separate .cc

Summary:
The fact that `sanitizer_allocator_checks.h` is including `sanitizer_errno.h`
creates complications for future changes, where it would conflict with `errno.h`
definitions on Android and Fuchsia (macro redefinition).

By moving the portion that sets errno in the checks to a separate compilation
unit, we avoid the inclusion of the header there, which solves the issue.

Not that it is not vital to have that function in a header as it is called as a
result of an unlikely event, and doesn't need to be inlined.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: kubamracek, llvm-commits, mgorny

Differential Revision: https://reviews.llvm.org/D38706

llvm-svn: 315319

compiler-rt/lib/sanitizer_common/CMakeLists.txt

@@ -3,6 +3,7 @@
 
 set(SANITIZER_SOURCES_NOTERMINATION
   sanitizer_allocator.cc
+  sanitizer_allocator_checks.cc
   sanitizer_common.cc
   sanitizer_deadlock_detector1.cc
   sanitizer_deadlock_detector2.cc

compiler-rt/lib/sanitizer_common/sanitizer_allocator_checks.cc

@@ -0,0 +1,23 @@
+//===-- sanitizer_allocator_checks.cc ---------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Various checks shared between ThreadSanitizer, MemorySanitizer, etc. memory
+// allocators.
+//
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_errno.h"
+
+namespace __sanitizer {
+
+void SetErrnoToENOMEM() {
+  errno = errno_ENOMEM;
+}
+
+} // namespace __sanitizer

compiler-rt/lib/sanitizer_common/sanitizer_allocator_checks.h

@@ -15,17 +15,22 @@
 #ifndef SANITIZER_ALLOCATOR_CHECKS_H
 #define SANITIZER_ALLOCATOR_CHECKS_H
 
-#include "sanitizer_errno.h"
 #include "sanitizer_internal_defs.h"
 #include "sanitizer_common.h"
 #include "sanitizer_platform.h"
 
 namespace __sanitizer {
 
+// The following is defined in a separate compilation unit to avoid pulling in
+// sanitizer_errno.h in this header, which leads to conflicts when other system
+// headers include errno.h. This is usually the result of an unlikely event,
+// and as such we do not care as much about having it inlined.
+void SetErrnoToENOMEM();
+
 // A common errno setting logic shared by almost all sanitizer allocator APIs.
 INLINE void *SetErrnoOnNull(void *ptr) {
   if (UNLIKELY(!ptr))
-    errno = errno_ENOMEM;
+    SetErrnoToENOMEM();
   return ptr;
 }