Fix handling of R_SPARC_UA32 relocations in linker

  These refer to unaligned locations that need to be written
  byte-at-a-time. This fixes the SPARC ghci failures in
  the current head.

diff --git a/rts/Linker.c b/rts/Linker.c
index d41ede6..b123f78 100644 (file)
--- a/rts/Linker.c
+++ b/rts/Linker.c
@@ -3544,17 +3544,26 @@ do_Elf_Rela_relocations ( ObjectCode* oc, char* ehdrC,
             w1 |= w2;
             *pP = w1;
             break;
             w1 |= w2;
             *pP = w1;
             break;

+

          /* According to the Sun documentation:
             R_SPARC_UA32
             This relocation type resembles R_SPARC_32, except it refers to an
             unaligned word. That is, the word to be relocated must be treated
             as four separate bytes with arbitrary alignment, not as a word
             aligned according to the architecture requirements.
          /* According to the Sun documentation:
             R_SPARC_UA32
             This relocation type resembles R_SPARC_32, except it refers to an
             unaligned word. That is, the word to be relocated must be treated
             as four separate bytes with arbitrary alignment, not as a word
             aligned according to the architecture requirements.

-
-            (JRS: which means that freeloading on the R_SPARC_32 case
-            is probably wrong, but hey ...)

          */
          case R_SPARC_UA32:
          */
          case R_SPARC_UA32:

+            w2 = (Elf_Word)value;
+
+            // SPARC doesn't do misaligned writes of 32 bit words,
+           //       so we have to do this one byte-at-a-time.
+           char *pPc   = (char*)pP;
+           pPc[0]      = (char) ((Elf_Word)(w2 & 0xff000000) >> 24);
+           pPc[1]      = (char) ((Elf_Word)(w2 & 0x00ff0000) >> 16);
+           pPc[2]      = (char) ((Elf_Word)(w2 & 0x0000ff00) >> 8);
+           pPc[3]      = (char) ((Elf_Word)(w2 & 0x000000ff));
+           break;
+

          case R_SPARC_32:
             w2 = (Elf_Word)value;
             *pP = w2;
          case R_SPARC_32:
             w2 = (Elf_Word)value;
             *pP = w2;