ELF unexec: Merge Alpha and MIPS COFF debug handling

* unexelf.c (unexec): Merge Alpha and MIPS COFF debug handling.
Don't find .mdebug section index, find the section in the loop.
Allow for unlikely possibility that .mdebug is located at sh_offset
before bss segment, by calculating move from difference in
sh_offset rather than just assuming new_data2_size.  Simplify
cbLineOffset handling.

1 files changed, 29 insertions, 67 deletions

diff --git a/src/unexelf.c b/src/unexelf.c
index d6c66488cc7..0065491b453 100644
--- a/src/unexelf.c
+++ b/src/unexelf.c
@@ -660,9 +660,6 @@ unexec (const char *new_name, const char *old_name)
   ptrdiff_t n, nn;
   ptrdiff_t old_bss_index, old_sbss_index, old_plt_index;
   ptrdiff_t old_data_index, new_data2_index;
-#if defined _SYSTYPE_SYSV || defined __sgi
-  ptrdiff_t old_mdebug_index;
-#endif
   struct stat stat_buf;
   off_t old_file_size;
 
@@ -706,13 +703,6 @@ unexec (const char *new_name, const char *old_name)
   old_section_names = (char *) old_base
     + OLD_SECTION_H (old_file_h->e_shstrndx).sh_offset;
 
-  /* Find the mdebug section, if any.  */
-
-#if defined _SYSTYPE_SYSV || defined __sgi
-  old_mdebug_index = find_section (".mdebug", old_section_names,
-                                   old_name, old_file_h, old_section_h, 1);
-#endif
-
   /* Find the old .bss section.  Figure out parameters of the new
      data2 and bss sections.  */
 
@@ -1055,51 +1045,31 @@ temacs:
 
       memcpy (new_shdr->sh_offset + new_base, src, new_shdr->sh_size);
 
-#if defined __alpha__ && !defined __OpenBSD__
-      /* Update Alpha COFF symbol table: */
-      if (strcmp (old_section_names + old_shdr->sh_name, ".mdebug") == 0)
-        {
-          pHDRR symhdr = (pHDRR) (new_shdr->sh_offset + new_base);
-
-          symhdr->cbLineOffset += new_data2_size;
-          symhdr->cbDnOffset += new_data2_size;
-          symhdr->cbPdOffset += new_data2_size;
-          symhdr->cbSymOffset += new_data2_size;
-          symhdr->cbOptOffset += new_data2_size;
-          symhdr->cbAuxOffset += new_data2_size;
-          symhdr->cbSsOffset += new_data2_size;
-          symhdr->cbSsExtOffset += new_data2_size;
-          symhdr->cbFdOffset += new_data2_size;
-          symhdr->cbRfdOffset += new_data2_size;
-          symhdr->cbExtOffset += new_data2_size;
-        }
-#endif /* __alpha__ && !__OpenBSD__ */
-
-#if defined (_SYSTYPE_SYSV)
-      if (new_shdr->sh_type == SHT_MIPS_DEBUG
-          && old_mdebug_index != -1)
+#if (defined __alpha__ && !defined __OpenBSD__) || defined _SYSTYPE_SYSV
+      /* Update Alpha and MIPS COFF debug symbol table.  */
+      if (strcmp (old_section_names + new_shdr->sh_name, ".mdebug") == 0
+          && new_shdr->sh_offset - old_shdr->sh_offset != 0
+#if defined _SYSTYPE_SYSV
+          && new_shdr->sh_type == SHT_MIPS_DEBUG
+#endif
+          )
         {
-          ptrdiff_t new_offset = new_shdr->sh_offset;
-          ptrdiff_t old_offset = OLD_SECTION_H (old_mdebug_index).sh_offset;
-          ptrdiff_t diff = new_offset - old_offset;
+          ptrdiff_t diff = new_shdr->sh_offset - old_shdr->sh_offset;
           HDRR *phdr = (HDRR *) (new_shdr->sh_offset + new_base);
 
-          if (diff)
-            {
-              phdr->cbLineOffset += diff;
-              phdr->cbDnOffset   += diff;
-              phdr->cbPdOffset   += diff;
-              phdr->cbSymOffset  += diff;
-              phdr->cbOptOffset  += diff;
-              phdr->cbAuxOffset  += diff;
-              phdr->cbSsOffset   += diff;
-              phdr->cbSsExtOffset += diff;
-              phdr->cbFdOffset   += diff;
-              phdr->cbRfdOffset  += diff;
-              phdr->cbExtOffset  += diff;
-            }
+          phdr->cbLineOffset += diff;
+          phdr->cbDnOffset += diff;
+          phdr->cbPdOffset += diff;
+          phdr->cbSymOffset += diff;
+          phdr->cbOptOffset += diff;
+          phdr->cbAuxOffset += diff;
+          phdr->cbSsOffset += diff;
+          phdr->cbSsExtOffset += diff;
+          phdr->cbFdOffset += diff;
+          phdr->cbRfdOffset += diff;
+          phdr->cbExtOffset += diff;
         }
-#endif /* _SYSTYPE_SYSV */
+#endif /* __alpha__ || _SYSTYPE_SYSV */
 
 #if __sgi
       /* Adjust  the HDRR offsets in .mdebug and copy the
@@ -1110,7 +1080,8 @@ temacs:
          the ld bug that gets the line table in a hole in the
          elf file rather than in the .mdebug section proper.
          David Anderson. davea@sgi.com  Jan 16,1994.  */
-      if (n == old_mdebug_index)
+      if (strcmp (old_section_names + new_shdr->sh_name, ".mdebug") == 0
+          && new_shdr->sh_offset - old_shdr->sh_offset != 0)
         {
 #define MDEBUGADJUST(__ct,__fileaddr)           \
   if (n_phdrr->__ct > 0)                        \
@@ -1120,7 +1091,7 @@ temacs:
 
           HDRR *o_phdrr = (HDRR *) ((byte *) old_base + old_shdr->sh_offset);
           HDRR *n_phdrr = (HDRR *) ((byte *) new_base + new_shdr->sh_offset);
-          unsigned movement = new_data2_size;
+          ptrdiff_t movement = new_shdr->sh_offset - old_shdr->sh_offset;
 
           MDEBUGADJUST (idnMax, cbDnOffset);
           MDEBUGADJUST (ipdMax, cbPdOffset);
@@ -1136,22 +1107,13 @@ temacs:
              requires special handling.  */
           if (n_phdrr->cbLine > 0)
             {
+              n_phdrr->cbLineOffset += movement;
+
               if (o_phdrr->cbLineOffset > (old_shdr->sh_offset
                                            + old_shdr->sh_size))
-                {
-                  /* line data is in a hole in elf. do special copy and adjust
-                     for this ld mistake.
-                     */
-                  n_phdrr->cbLineOffset += movement;
-
-                  memcpy (n_phdrr->cbLineOffset + new_base,
-                          o_phdrr->cbLineOffset + old_base, n_phdrr->cbLine);
-                }
-              else
-                {
-                  /* somehow line data is in .mdebug as it is supposed to be.  */
-                  MDEBUGADJUST (cbLine, cbLineOffset);
-                }
+                /* If not covered by section, it hasn't yet been copied.  */
+                memcpy (n_phdrr->cbLineOffset + new_base,
+                        o_phdrr->cbLineOffset + old_base, n_phdrr->cbLine);
             }
         }
 #endif /* __sgi */