The initial commit of the Nios II GCC backend has an ABI conformance bug
in that it initializes the GOT pointer from _GLOBAL_OFFSET_TABLE_ rather
than _gp_got, as specified in the ABI. As a consequence of this,
GCC-generated code can only address 32K of GOT rather than 64K as
documented in the ABI. This patch fixes that.
This patch depends on the binutils patch I posted earlier today:
https://sourceware.org/ml/binutils/2014-02/msg00009.html
as the linker was not previously defining the _gp_got symbol specified
in the ABI document. There's a potential compatibility issue here with
old versions of the linker, but we'd rather have the first official
release of GCC for Nios II implement this correctly.
-Sandra
2014-02-02 Sandra Loosemore <san...@codesourcery.com>
gcc/
* config/nios2/nios2.md (load_got_register): Initialize GOT
pointer from _gp_got instead of _GLOBAL_OFFSET_TABLE_.
* config/nios2/nios2.c (nios2_function_profiler): Likewise.
libgcc/
* config/nios2/crti.S (_init): Initialize GOT pointer from
_gp_got instead of _GLOBAL_OFFSET_TABLE_.
Index: gcc/config/nios2/nios2.md
===================================================================
--- gcc/config/nios2/nios2.md (revision 207406)
+++ gcc/config/nios2/nios2.md (working copy)
@@ -1015,8 +1015,8 @@
""
"nextpc\\t%0
\\t1:
-\\tmovhi\\t%1, %%hiadj(_GLOBAL_OFFSET_TABLE_ - 1b)
-\\taddi\\t%1, %1, %%lo(_GLOBAL_OFFSET_TABLE_ - 1b)"
+\\tmovhi\\t%1, %%hiadj(_gp_got - 1b)
+\\taddi\\t%1, %1, %%lo(_gp_got - 1b)"
[(set_attr "length" "12")])
;; Read thread pointer register
Index: gcc/config/nios2/nios2.c
===================================================================
--- gcc/config/nios2/nios2.c (revision 207406)
+++ gcc/config/nios2/nios2.c (working copy)
@@ -667,8 +667,8 @@ nios2_function_profiler (FILE *file, int
if (flag_pic)
{
fprintf (file, "\tnextpc\tr2\n");
- fprintf (file, "\t1: movhi\tr3, %%hiadj(_GLOBAL_OFFSET_TABLE_ - 1b)\n");
- fprintf (file, "\taddi\tr3, r3, %%lo(_GLOBAL_OFFSET_TABLE_ - 1b)\n");
+ fprintf (file, "\t1: movhi\tr3, %%hiadj(_gp_got - 1b)\n");
+ fprintf (file, "\taddi\tr3, r3, %%lo(_gp_got - 1b)\n");
fprintf (file, "\tadd\tr2, r2, r3\n");
fprintf (file, "\tldw\tr2, %%call(_mcount)(r2)\n");
fprintf (file, "\tcallr\tr2\n");
Index: libgcc/config/nios2/crti.S
===================================================================
--- libgcc/config/nios2/crti.S (revision 207406)
+++ libgcc/config/nios2/crti.S (working copy)
@@ -56,8 +56,8 @@ _init:
addi fp, sp, 8
#ifdef linux
nextpc r22
-1: movhi r2, %hiadj(_GLOBAL_OFFSET_TABLE_ - 1b)
- addi r2, r2, %lo(_GLOBAL_OFFSET_TABLE_ - 1b)
+1: movhi r2, %hiadj(_gp_got - 1b)
+ addi r2, r2, %lo(_gp_got - 1b)
add r22, r22, r2
#endif
@@ -80,8 +80,8 @@ _fini:
addi fp, sp, 8
#ifdef linux
nextpc r22
-1: movhi r2, %hiadj(_GLOBAL_OFFSET_TABLE_ - 1b)
- addi r2, r2, %lo(_GLOBAL_OFFSET_TABLE_ - 1b)
+1: movhi r2, %hiadj(_gp_got - 1b)
+ addi r2, r2, %lo(_gp_got - 1b)
add r22, r22, r2
#endif
