[libunwind] Make findUnwindSectionsByPhdr static

[rprichard]

Summary

Currently, this function is present in the dynsym table of
libunwind.so (on ELF targets). Make the function static instead.

In the previous release (LLVM 10.x), this function was instead a lambda
function inside LocalAddressSpace::findUnwindSections, and because
LocalAddressSpace was marked with _LIBUNWIND_HIDDEN, the lambda
function was also a hidden symbol.

[rprichard]

(This change was previously accepted when it was part of D86254.)

[hans]

From the discussion on D86254, this should be cherry-picked to 11.x right?

[rprichard]

In D86372#2234249, @hans wrote:

From the discussion on D86254, this should be cherry-picked to 11.x right?

Correct. This findUnwindSectionsByPhdr change (D86372) is needed for 11.

[rprichard]

In D86372#2234459, @rprichard wrote:

In D86372#2234249, @hans wrote:

From the discussion on D86254, this should be cherry-picked to 11.x right?

Correct. This findUnwindSectionsByPhdr change (D86372) is needed for 11.

If we do cherry-pick this to 11, I'm assuming that's something @hans would need to do, not I. Does there need to be a Bugzilla bug for this?

[hans]

In D86372#2235806, @rprichard wrote:

In D86372#2234459, @rprichard wrote:

In D86372#2234249, @hans wrote:

From the discussion on D86254, this should be cherry-picked to 11.x right?

Correct. This findUnwindSectionsByPhdr change (D86372) is needed for 11.

If we do cherry-pick this to 11, I'm assuming that's something @hans would need to do, not I. Does there need to be a Bugzilla bug for this?

No need to file a bug as long as I'm aware. I've cherry-picked it as 83338bed0c2078870b36a81fe9a36723bd3be2e5. Thanks!

libunwind/src/AddressSpace.hpp

if (cbdata->targetAddr >= begin && cbdata->targetAddr < end) {
       cbdata->sects->dso_base = begin;
       cbdata->sects->dwarf_section_length = phdr->p_memsz;
       return true;
     }
   }
   return false;
 }
 
-int findUnwindSectionsByPhdr(struct dl_phdr_info *pinfo, size_t pinfo_size,
-                             void *data) {
+static int findUnwindSectionsByPhdr(struct dl_phdr_info *pinfo,
+                                    size_t pinfo_size, void *data) {
   auto cbdata = static_cast<dl_iterate_cb_data *>(data);
   if (pinfo->dlpi_phnum == 0 || cbdata->targetAddr < pinfo->dlpi_addr)
     return 0;
 #if defined(_LIBUNWIND_USE_FRAME_HEADER_CACHE)
   if (ProcessFrameHeaderCache.find(pinfo, pinfo_size, data))
     return 1;
 #endif
 
#endif
   cbdata->sects->dwarf_section_length = 0;
   return 0;
 }
 
 #else  // defined(LIBUNWIND_SUPPORT_DWARF_UNWIND)
 // Given all the #ifdef's above, the code here is for
 // defined(LIBUNWIND_ARM_EHABI)
 
-int findUnwindSectionsByPhdr(struct dl_phdr_info *pinfo, size_t, void *data) {
+static int findUnwindSectionsByPhdr(struct dl_phdr_info *pinfo, size_t,
+                                    void *data) {
   auto *cbdata = static_cast<dl_iterate_cb_data *>(data);
   bool found_obj = false;
   bool found_hdr = false;
 
   assert(cbdata);
   assert(cbdata->sects);
 
   if (cbdata->targetAddr < pinfo->dlpi_addr)