build/build-clang/find_symbolizer_linux_clang_10.patch

   1 We currently need this patch because ASan only searches PATH to find the
   2 llvm-symbolizer binary to symbolize ASan traces. On testing machines, this
   3 can be installed in PATH easily. However, for e.g. the ASan Nightly Project,
   4 where we ship an ASan build, including llvm-symbolizer, to the user, we
   5 cannot expect llvm-symbolizer to be on PATH. Instead, we should try to look
   6 it up next to the binary. This patch implements the functionality for Linux
   7 only until there is similar functionality provided upstream.
   8
   9 diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_file.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_file.cpp
  10 index 79930d79425..cfb4f90c0d5 100644
  11 --- a/compiler-rt/lib/sanitizer_common/sanitizer_file.cpp
  12 +++ b/compiler-rt/lib/sanitizer_common/sanitizer_file.cpp
  13 @@ -20,6 +20,10 @@
  14  #include "sanitizer_common.h"
  15  #include "sanitizer_file.h"
  16
  17 +#if SANITIZER_LINUX
  18 +#include "sanitizer_posix.h"
  19 +#endif
  20 +
  21  namespace __sanitizer {
  22
  23  void CatastrophicErrorWrite(const char *buffer, uptr length) {
  24 @@ -194,6 +198,34 @@ char *FindPathToBinary(const char *name) {
  25      if (*end == '\0') break;
  26      beg = end + 1;
  27    }
  28 +
  29 +#if SANITIZER_LINUX
  30 +  // If we cannot find the requested binary in PATH, we should try to locate
  31 +  // it next to the binary, in case it is shipped with the build itself
  32 +  // (e.g. llvm-symbolizer shipped with sanitizer build to symbolize on client.
  33 +  if (internal_readlink("/proc/self/exe", buffer.data(), kMaxPathLength) < 0)
  34 +    return nullptr;
  35 +
  36 +  uptr buf_len = internal_strlen(buffer.data());
  37 +
  38 +  /* Avoid using dirname() here */
  39 +  while (buf_len > 0) {
  40 +    if (buffer[buf_len - 1] == '/')
  41 +      break;
  42 +    buf_len--;
  43 +  }
  44 +
  45 +  if (!buf_len)
  46 +    return nullptr;
  47 +
  48 +  if (buf_len + name_len + 1 <= kMaxPathLength) {
  49 +    internal_memcpy(&buffer[buf_len], name, name_len);
  50 +    buffer[buf_len + name_len] = '\0';
  51 +    if (FileExists(buffer.data()))
  52 +      return internal_strdup(buffer.data());
  53 +  }
  54 +#endif
  55 +
  56    return nullptr;
  57  }
  58