[NFC][compiler-rt][hwasan] Move allocation functions into their own file

[leonardchan]

Summary

This removes the __sanitizer_* allocation function definitions from hwasan_interceptors.cpp and moves them into their own file. This way implementations that do not use interceptors at all can just ignore (almost) everything in hwasan_interceptors.cpp.

Also remove some unused headers in hwasan_interceptors.cpp after the move.

[eugenis]

s/vfork/fork/ in the description

I'm afraid removing the fork interceptor will break Android. This is a pretty uncommon condition, but still. It is interesting to note that ASan does not have this fork protection, see https://github.com/google/sanitizers/issues/774 for some history.

I wonder if this could be replaced with pthread_atfork. The order of callback execution seems right, as long as hwasan is registered first. Or, if you want to make progress, add SANITIZER_ANDROID ifdef somewhere.

[mcgrathr]

I think probably the better refactoring here would be to split this file in two: one containing just the allocation functions; and a second with everything else.
On Fuchsia, we'll use the allocation functions but none of the rest of it. So the second whole file could just be under #if !SANITIZER_FUCHSIA.

[leonardchan]

In D103564#2795287, @mcgrathr wrote:

I think probably the better refactoring here would be to split this file in two: one containing just the allocation functions; and a second with everything else.
On Fuchsia, we'll use the allocation functions but none of the rest of it. So the second whole file could just be under #if !SANITIZER_FUCHSIA.

I don't think we can move the __sanitizer_* allocation functions since they're used for aliases for their libc equivalents which require definitions in the same TU:

/usr/local/google/home/leonardchan/llvm-monorepo/llvm-project-4/compiler-rt/lib/hwasan/hwasan_interceptors.cpp:59:1: error: alias must point to a defined variable or function
INTERCEPTOR_ALIAS(void *, aligned_alloc, SIZE_T alignment, SIZE_T size);
^
/usr/local/google/home/leonardchan/llvm-monorepo/llvm-project-4/compiler-rt/lib/hwasan/hwasan_interceptors.cpp:53:7: note: expanded from macro 'INTERCEPTOR_ALIAS'
      ALIAS("__sanitizer_" #FN);                                             \
      ^

Perhaps it might just be easier to just wrap the part of hwasan_interceptors.cpp that don't include the allocation functions with #if !SANITIZER_FUCHSIA, or as @eugenis suggested wrap the fork interceptor with #if SANITIZER_ANDROID.

[mcgrathr]

In D103564#2797657, @leonardchan wrote:

I don't think we can move the __sanitizer_* allocation functions since they're used for aliases for their libc equivalents which require definitions in the same TU:

What I suggested is moving *everything* related to the allocation functions into a separate file.

[leonardchan]

Followed up with Roland's suggestion and moved everything relating to the allocation functions.

[mcgrathr]

compiler-rt/lib/hwasan/hwasan_interceptors.cpp

351

blank lines around #else and #endif lines. But here I think you just omit this. We can define the empty function in a fuchsia-specific file.

[vitalybuka]

compiler-rt/lib/hwasan/hwasan_interceptors.cpp

351

+1 to "empty function in a fuchsia-specific file"

[leonardchan]

compiler-rt/lib/hwasan/hwasan_interceptors.cpp

351

Will add in an eventual hwasan_fuchsia.cpp.

[thakis]

this breaks tests: http://45.33.8.238/linux/48401/step_10.txt

// CHECK: #0 {{.*}} in {{.*}}free{{.*}} {{.*}}hwasan_interceptors.cpp

vs

13: #0 0x5647a467e9a0 in free ../../compiler-rt/lib/hwasan/hwasan_allocation_functions.cpp:75:3

need to update the path in that test

[leonardchan]

In D103564#2806292, @thakis wrote:

this breaks tests: http://45.33.8.238/linux/48401/step_10.txt

// CHECK: #0 {{.*}} in {{.*}}free{{.*}} {{.*}}hwasan_interceptors.cpp

vs

13: #0 0x5647a467e9a0 in free ../../compiler-rt/lib/hwasan/hwasan_allocation_functions.cpp:75:3

need to update the path in that test

Fixed in a9ea0a6a77b30305bfbe1b06c30bf6136f64c1ad.

compiler-rt/lib/hwasan/hwasan_interceptors.cpp

 //===-- hwasan_interceptors.cpp -------------------------------------------===//
 //
 // 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 HWAddressSanitizer.
 //
 // Interceptors for standard library functions.
 //
 // FIXME: move as many interceptors as possible into
 // sanitizer_common/sanitizer_common_interceptors.h
 //===----------------------------------------------------------------------===//
 
 #include "interception/interception.h"
 #include "hwasan.h"
 #include "hwasan_allocator.h"
 #include "hwasan_mapping.h"
 #include "hwasan_thread.h"
 #include "hwasan_poisoning.h"
 #include "hwasan_report.h"
+#include "sanitizer_common/sanitizer_platform_limits_fuchsia.h"
 #include "sanitizer_common/sanitizer_platform_limits_posix.h"
 #include "sanitizer_common/sanitizer_allocator.h"
 #include "sanitizer_common/sanitizer_allocator_interface.h"
 #include "sanitizer_common/sanitizer_allocator_internal.h"
 #include "sanitizer_common/sanitizer_atomic.h"
 #include "sanitizer_common/sanitizer_common.h"
 #include "sanitizer_common/sanitizer_errno.h"
 #include "sanitizer_common/sanitizer_stackdepot.h"
 #include "sanitizer_common/sanitizer_libc.h"
 #include "sanitizer_common/sanitizer_linux.h"
 #include "sanitizer_common/sanitizer_tls_get_addr.h"
 
 #include <stdarg.h>
 // ACHTUNG! No other system header includes in this file.
 // Ideally, we should get rid of stdarg.h as well.
 
 using namespace __hwasan;
 
 using __sanitizer::memory_order;
 using __sanitizer::atomic_load;
void * __sanitizer_malloc(uptr size) {
   if (UNLIKELY(!hwasan_init_is_running))
     ENSURE_HWASAN_INITED();
   if (UNLIKELY(!hwasan_inited))
     // Hack: dlsym calls malloc before REAL(malloc) is retrieved from dlsym.
     return AllocateFromLocalPool(size);
   return hwasan_malloc(size, &stack);
 }
 
+#if !SANITIZER_FUCHSIA
 #if HWASAN_WITH_INTERCEPTORS
 #define INTERCEPTOR_ALIAS(RET, FN, ARGS...)                                  \
   extern "C" SANITIZER_INTERFACE_ATTRIBUTE RET WRAP(FN)(ARGS)                \
       ALIAS("__sanitizer_" #FN);                                             \
   extern "C" SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE RET FN(  \
       ARGS) ALIAS("__sanitizer_" #FN)
 
 INTERCEPTOR_ALIAS(int, posix_memalign, void **memptr, SIZE_T alignment,
                   SIZE_T size);
#if defined(__linux__)
   INTERCEPT_FUNCTION(vfork);
 #endif  // __linux__
   INTERCEPT_FUNCTION(pthread_create);
 #endif
 
   inited = 1;
 }
 } // namespace __hwasan
+
+#else  // !SANITIZER_FUCHSIA
+
+namespace __hwasan {
+void InitializeInterceptors() {}
+}  // namespace __hwasan
+
+#endif  // !SANITIZER_FUCHSIA