ARC: ldso: Use @pcl syntax.

Signed-off-by: Joern Rennecke <joern.rennecke@embecosm.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

ldso/ldso/arc/dl-startup.h

@@ -33,14 +33,9 @@ __asm__(
     "   ; If ldso ran as cmd with executable file nm as arg     \n"
     "   ; skip the extra args calc by dl_start()                \n"
     "   ld_s    r1, [sp]       ; orig argc from aux-vec Tbl     \n"
-#ifdef STAR_9000535888_FIXED
-    "   ld      r12, [pcl, _dl_skip_args-.+(.&2)]               \n"
-#else
-    "   add     r12, pcl, _dl_skip_args-.+(.&2)                 \n"
-    "   ld      r12, [r12]                                      \n"
-#endif
+    "   ld      r12, [pcl, _dl_skip_args@pcl]                   \n"
 
-    "   add     r2, pcl, _dl_fini-.+(.&2)   ; finalizer         \n"
+    "   add     r2, pcl, _dl_fini@pcl       ; finalizer         \n"
 
     "   add2    sp, sp, r12    ; discard argv entries from stack\n"
     "   sub_s   r1, r1, r12    ; adjusted argc, on stack        \n"

ldso/ldso/arc/dl-sysdep.h

@@ -124,14 +124,21 @@ static __always_inline Elf32_Addr elf_machine_dynamic(void)
 /* Return the run-time load address of the shared object.  */
 static __always_inline Elf32_Addr elf_machine_load_address(void)
 {
-    /* To find the loadaddr we subtract the runtime addr of any symbol
-     * say _dl_start from it's build-time addr.
+    /* To find the loadaddr we subtract the runtime addr of a non-local symbol
+     * say _DYNAMIC from it's build-time addr.
+     * N.B., gotpc loads get optimized by the linker if it finds the symbol
+     * is resolved locally.
+     * A more robust - and efficient - solution would be to use a symbol
+     * set by the linker.  To make it actually save space, we'd have to
+     * suppress the unwanted text relocation in the linked dso, though.
+     * (I.e. in ldso.so.*, though it's just another dso as far as bfd/ld
+     * are concerned.)
      */
 	Elf32_Addr addr, tmp;
 	__asm__ (
-        "ld  %1, [pcl, _dl_start@gotpc] ;build addr of _dl_start   \n"
-        "add %0, pcl, _dl_start-.+(.&2) ;runtime addr of _dl_start \n"
-        "sub %0, %0, %1                 ;delta                     \n"
+        "ld  %1, [pcl, _DYNAMIC@gotpc] ;build addr of _DYNAMIC"   "\n"
+        "add %0, pcl, _DYNAMIC@pcl     ;runtime addr of _DYNAMIC" "\n"
+        "sub %0, %0, %1                ;delta"                    "\n"
         : "=&r" (addr), "=r"(tmp)
     );
 	return addr;