[compiler-rt] Move __sanitizer_mallinfo to separate header

[leonardchan]

Summary

mallinfo is platform-specific and not specified by either posix or the C standard, but the hwasan interface unconditionally exposes __sanitizer_mallinfo which returns a struct __sanitizer_struct_mallinfo which is defined in sanitizer_platform_limits_posix.h, so this should also be available for fuchsia to provide __sanitizer_mallinfo. Fuchsia doesn't need the rest of what's in sanitizer_platform_limits_posix.h so we can just move it to its own header.

Exposing this and not forcing it to hide behind SANITIZER_INTERCEPT_MALLOPT_AND_MALLINFO fixes the test failures found after landing D145718.

[phosek]

I'm not a big fan of this change since Fuchsia is not POSIX and most of this files isn't useful on Fuchsia. mallinfo is also not specified by neither POSIX nor C standard. Would it be possible to move the definition of __sanitizer_struct_mallinfo to a separate header file?

[leonardchan]

In D147092#4229150, @phosek wrote:

I'm not a big fan of this change since Fuchsia is not POSIX and most of this files isn't useful on Fuchsia. mallinfo is also not specified by neither POSIX nor C standard. Would it be possible to move the definition of __sanitizer_struct_mallinfo to a separate header file?

Something like this?

[mcgrathr]

I agree that isolating things away from an #if-ridden grab-bag is the cleanest approach here.

compiler-rt/lib/sanitizer_common/sanitizer_mallinfo.h

20 ↗

(On Diff #509190)

It's usually a good idea to put blank lines around the # directive lines.

compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h

 //===-- sanitizer_platform_limits_posix.h ---------------------------------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 //
 // This file is a part of Sanitizer common code.
 //
 // Sizes and layouts of platform-specific POSIX data structures.
 //===----------------------------------------------------------------------===//
 
 #ifndef SANITIZER_PLATFORM_LIMITS_POSIX_H
 #define SANITIZER_PLATFORM_LIMITS_POSIX_H
 
-#if SANITIZER_LINUX || SANITIZER_APPLE
+#if SANITIZER_LINUX || SANITIZER_APPLE || SANITIZER_FUCHSIA
 
 #include "sanitizer_internal_defs.h"
 #include "sanitizer_platform.h"
 
 #if SANITIZER_APPLE
 #include <sys/cdefs.h>
 #if !__DARWIN_ONLY_64_BIT_INO_T
 #define SANITIZER_HAS_STAT64 1

 #endif // SANITIZER_LINUX
 
 #if SANITIZER_ANDROID
 struct __sanitizer_struct_mallinfo {
   uptr v[10];
 };
 #endif
 
-#if SANITIZER_LINUX && !SANITIZER_ANDROID
+#if (SANITIZER_LINUX && !SANITIZER_ANDROID) || SANITIZER_FUCHSIA
 struct __sanitizer_struct_mallinfo {
   int v[10];
 };
 
 extern unsigned struct_ustat_sz;
 extern unsigned struct_rlimit64_sz;
 extern unsigned struct_statvfs64_sz;
 
union {
     __sanitizer_sighandler_ptr handler;
   };
 #if SANITIZER_FREEBSD
   int sa_flags;
   __sanitizer_sigset_t sa_mask;
 #else
 #if defined(__s390x__)
   int sa_resv;
-#else
+#elif !SANITIZER_FUCHSIA
   __sanitizer_sigset_t sa_mask;
 #endif
 #ifndef __mips__
 #if defined(__sparc__)
 #if __GLIBC_PREREQ (2, 20)
   // On sparc glibc 2.19 and earlier sa_flags was unsigned long.
 #if defined(__arch64__)
   // To maintain ABI compatibility on sparc64 when switching to an int,