or1k: Avoid R_OR1K_GOT16 overflow failures in presence of R_OR1K_GOT_AHI16

Now that we support R_OR1K_GOT_AHI16 we can relax the R_OR1K_GOT16
overflow validation check if the section has R_OR1K_GOT_AHI16.

We cannot simple disable R_OR1K_GOT16 overflow validation as there will
still be binaries that will have only R_OR1K_GOT16.  The
R_OR1K_GOT_AHI16 relocation will only be added by GCC when building with
the option -mcmodel=large.

This assumes that R_OR1K_GOT_AHI16 will come before R_OR1K_GOT16, which
is the code pattern that will be emitted by GCC.

bfd/ChangeLog:

	PR 21464
	* elf32-or1k.c (or1k_elf_relocate_section): Relax R_OR1K_GOT16
	overflow check if we have R_OR1K_GOT_AHI16 followed by
	R_OR1K_GOT16.

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index c4a83dfe4f7851900da27d1c79688cb442e430b7..8293e9d7952eabcf8e2f61cfc845b1f5c4337a5f 100644 (file)
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,10 @@
+2021-05-06  Stafford Horne  <shorne@gmail.com>
+
+       PR 21464
+       * elf32-or1k.c (or1k_elf_relocate_section): Relax R_OR1K_GOT16
+       overflow check if we have R_OR1K_GOT_AHI16 followed by
+       R_OR1K_GOT16.
+
 2021-05-06  Stafford Horne  <shorne@gmail.com>
 
        PR 21464

diff --git a/bfd/elf32-or1k.c b/bfd/elf32-or1k.c
index 1b8938df37f9125c7b1e5487c12081a47678dab7..5eca4300c4575b8cd529234964339b65dfcec523 100644 (file)
--- a/bfd/elf32-or1k.c
+++ b/bfd/elf32-or1k.c
@@ -1278,6 +1278,7 @@ or1k_elf_relocate_section (bfd *output_bfd,
   asection *sgot, *splt;
   bfd_vma plt_base, got_base, got_sym_value;
   bool ret_val = true;
+  bool saw_gotha = false;
 
   if (htab == NULL)
     return false;
@@ -1485,6 +1486,16 @@ or1k_elf_relocate_section (bfd *output_bfd,
                || r_type == R_OR1K_GOT_AHI16)
              relocation -= got_sym_value;
 
+           if (r_type == R_OR1K_GOT_AHI16)
+             saw_gotha = true;
+
+           /* If we have a R_OR1K_GOT16 followed by a R_OR1K_GOT_AHI16
+              relocation we assume the code is doing the right thing to avoid
+              overflows.  Here we mask the lower 16-bit of the relocation to
+              avoid overflow validation failures.  */
+           if (r_type == R_OR1K_GOT16 && saw_gotha)
+             relocation &= 0xffff;
+
          /* Addend should be zero.  */
          if (rel->r_addend != 0)
            {