3616 SHF_GROUP sections should not be discarded via other COMDAT mechanisms
3709 need sloppy relocation for GNU .debug_macro
Reviewed by: Joshua M. Clulow <josh@sysmgr.org>
Reviewed by: Robert Mustacchi <rm@joyent.com>

*** 116,125 ****
--- 116,165 ----
          ld_eprintf(ofl, ERR_FATAL, MSG_INTL(MSG_ELF_NOGROUPSECT),
              ifl->ifl_name, EC_WORD(isp->is_scnndx), isp->is_name);
          return (NULL);
  }
  
+ /*
+  * When creating a .debug_macro section, in an attempt to make certain DWARF
+  * macro information shareable, the GNU compiler must construct group sections
+  * with a repeatable signature symbol while nevertheless having no actual
+  * symbol to refer to (because it relates to macros).
+  *
+  * We use this as yet another way to clue ourselves in that sloppy relocation
+  * will likely be required.
+  *
+  * The format of these gensym'd names is:
+  *    wm<offset size>.<encoded path name>.<lineno>.<32byte hash>
+  * Where the encoded file name may be absent.
+  */
+ static boolean_t
+ is_header_gensym(const char *name)
+ {
+         const char *c = NULL;
+ 
+         /* No room for leader, hash, and periods */
+         if (strlen(name) < 37)
+                 return (B_FALSE);
+ 
+         if ((strncmp(name, "wm4.", 4) != 0) &&
+           strncmp(name, "wm8.", 4) != 0)
+                 return (B_FALSE);
+ 
+         c = &name[strlen(name) - 33];
+         if (*c++ != '.')
+                 return (B_FALSE);
+ 
+         for (; *c != '\0'; c++) {
+                 if (!(((*c >= 'a') && (*c <= 'f')) ||
+                     ((*c >= '0') && (*c <= '9')))) {
+                         return (B_FALSE);
+                 }
+         }
+ 
+         return (B_TRUE);
+ }
+ 
  uintptr_t
  ld_group_process(Is_desc *gisc, Ofl_desc *ofl)
  {
          Ifl_desc        *gifl = gisc->is_file;
          Shdr            *sshdr, *gshdr = gisc->is_shdr;
*** 219,228 ****
--- 259,279 ----
                      gisc->is_name, str);
                  return (0);
          }
  
          /*
+          * If the signature symbol is a name generated by the GNU compiler to
+          * refer to a header, we need sloppy relocation.
+          */
+         if (is_header_gensym(str)) {
+             if ((ofl->ofl_flags1 & FLG_OF1_NRLXREL) == 0)
+                 ofl->ofl_flags1 |= FLG_OF1_RLXREL;
+             DBG_CALL(Dbg_sec_gnu_comdat(ofl->ofl_lml, gisc, TRUE,
+               (ofl->ofl_flags1 & FLG_OF1_RLXREL) != 0));
+         }
+ 
+         /*
           * Validate the section indices within the group.  If this is a COMDAT
           * group, mark each section as COMDAT.
           */
          for (ndx = 1; ndx < gd.gd_cnt; ndx++) {
                  Word    gndx;