[Sanitizers] Fix sanitizer_posix_libcdep.cc compilation on Solaris 11.5

[ro]

Summary

A recent build of Solaris 11.5 Beta (st_047) gained madvise(MADV_DONTDUMP)
support for Linux compatibility. This broke the compiler-rt build:

/vol/llvm/src/llvm/dist/projects/compiler-rt/lib/sanitizer_comm/sanitizer_posix_libcdep.cc: In function ‘bool __sanitizer::DontDumpShadowMemory(__sanitizer::uptr, __sanitizer::uptr)’:
/vol/llvm/src/llvm/dist/projects/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cc:81:18: error: invalid conversion from ‘void*’ to ‘caddr_t’ {aka ‘char*’} [-fpermissive]
   81 |   return madvise((void *)addr, length, MADV_DONTDUMP) == 0;
      |                  ^~~~~~~~~~~~
      |                  |
      |                  void*
In file included from /vol/llvm/src/llvm/dist/projects/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cc:32:
/usr/include/sys/mman.h:231:20: note:   initializing argument 1 of ‘int madvise(caddr_t, std::size_t, int)’
  231 | extern int madvise(caddr_t, size_t, int);
      |                    ^~~~~~~

The obvious fix is to use the same solution that has already been used a couple of
lines earlier:

// In the default Solaris compilation environment, madvise() is declared
// to take a caddr_t arg; casting it to void * results in an invalid
// conversion error, so use char * instead.

This allowed the compiler-rt build to finish and was tested successfully on
i386-pc-solaris2.11 and x86_64-pc-linux-gnu.

Ok for trunk?

[ro]

Ping? It's been a week and the patch is close to obvious.

[ro]

Ping^2. It's been two weeks now for a trivial patch fixing the build...

compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix_libcdep.cc

if (beg_aligned < end_aligned)
     // to take a caddr_t arg; casting it to void * results in an invalid
     // conversion error, so use char * instead.
     madvise((char *)beg_aligned, end_aligned - beg_aligned,
             SANITIZER_MADVISE_DONTNEED);
 }
 
 bool NoHugePagesInRegion(uptr addr, uptr size) {
 #ifdef MADV_NOHUGEPAGE  // May not be defined on old systems.
-  return madvise((void *)addr, size, MADV_NOHUGEPAGE) == 0;
+  return madvise((char *)addr, size, MADV_NOHUGEPAGE) == 0;
 #else
   return true;
 #endif  // MADV_NOHUGEPAGE
 }
 
 bool DontDumpShadowMemory(uptr addr, uptr length) {
 #if defined(MADV_DONTDUMP)
-  return madvise((void *)addr, length, MADV_DONTDUMP) == 0;
+  return madvise((char *)addr, length, MADV_DONTDUMP) == 0;
 #elif defined(MADV_NOCORE)
-  return madvise((void *)addr, length, MADV_NOCORE) == 0;
+  return madvise((char *)addr, length, MADV_NOCORE) == 0;
 #else
   return true;
 #endif  // MADV_DONTDUMP
 }
 
 static rlim_t getlim(int res) {
   rlimit rlim;
   CHECK_EQ(0, getrlimit(res, &rlim));