Combine ifdefs around dl_iterate_phdr in Unix/Signals.inc

This avoids the need to have two dummy implementations of
findModulesAndOffsets.

llvm-svn: 252531

1 files changed, 8 insertions, 13 deletions

diff --git a/llvm/lib/Support/Unix/Signals.inc b/llvm/lib/Support/Unix/Signals.inc
index d6d30bf0cb3..de98d4adf99 100644
--- a/llvm/lib/Support/Unix/Signals.inc
+++ b/llvm/lib/Support/Unix/Signals.inc
@@ -253,10 +253,9 @@ void llvm::sys::AddSignalHandler(void (*FnPtr)(void *), void *Cookie) {
   RegisterHandlers();
 }
 
-#if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
-
-#if HAVE_LINK_H && (defined(__linux__) || defined(__FreeBSD__) ||              \
-                    defined(__FreeBSD_kernel__) || defined(__NetBSD__))
+#if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES) && HAVE_LINK_H &&    \
+    (defined(__linux__) || defined(__FreeBSD__) ||                             \
+     defined(__FreeBSD_kernel__) || defined(__NetBSD__))
 struct DlIteratePhdrData {
   void **StackTrace;
   int depth;
@@ -289,6 +288,8 @@ static int dl_iterate_phdr_cb(dl_phdr_info *info, size_t size, void *arg) {
   return 0;
 }
 
+/// If this is an ELF platform, we can find all loaded modules and their virtual
+/// addresses with dl_iterate_phdr.
 static bool findModulesAndOffsets(void **StackTrace, int Depth,
                                   const char **Modules, intptr_t *Offsets,
                                   const char *MainExecutableName,
@@ -299,21 +300,15 @@ static bool findModulesAndOffsets(void **StackTrace, int Depth,
   return true;
 }
 #else
+/// This platform does not have dl_iterate_phdr, so we do not yet know how to
+/// find all loaded DSOs.
 static bool findModulesAndOffsets(void **StackTrace, int Depth,
                                   const char **Modules, intptr_t *Offsets,
                                   const char *MainExecutableName,
                                   StringSaver &StrPool) {
   return false;
 }
-#endif
-#else
-static bool findModulesAndOffsets(void **StackTrace, int Depth,
-                                  const char **Modules, intptr_t *Offsets,
-                                  const char *MainExecutableName,
-                                  StringSaver &StrPool) {
-  return false;
-}
-#endif // defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
+#endif // defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES) && ...
 
 // PrintStackTrace - In the case of a program crash or fault, print out a stack
 // trace so that the user has an indication of why and where we died.