[x86] Resolve non-PIC undefweak symbols in executable

[deliverable/binutils-gdb.git] / ld / emultempl / ppc32elf.em

diff --git a/ld/emultempl/ppc32elf.em b/ld/emultempl/ppc32elf.em
index 00a29e2f0aaf48a947bc5ee0471fa87775d0aa8a..a0255cd5323264a086f013048f4e8b30da12766a 100644 (file)
--- a/ld/emultempl/ppc32elf.em
+++ b/ld/emultempl/ppc32elf.em
@@ -1,5 +1,5 @@
 # This shell script emits a C file. -*- C -*-
-#   Copyright (C) 2003-2014 Free Software Foundation, Inc.
+#   Copyright (C) 2003-2016 Free Software Foundation, Inc.
 #
 # This file is part of the GNU Binutils.
 #
@@ -27,6 +27,7 @@ fragment <<EOF
 #include "libbfd.h"
 #include "elf32-ppc.h"
 #include "ldlex.h"
+#include "ldlang.h"
 
 #define is_ppc_elf(bfd) \
   (bfd_get_flavour (bfd) == bfd_target_elf_flavour \
@@ -40,13 +41,14 @@ static int old_got = 0;
 
 static bfd_vma pagesize = 0;
 
-static struct ppc_elf_params params = { PLT_UNSET, -1, 0, 0, 0, 0 };
+static struct ppc_elf_params params = { PLT_UNSET, -1, 0, 0, 0, 0, 0 };
 
 static void
 ppc_after_open_output (void)
 {
   if (params.emit_stub_syms < 0)
-    params.emit_stub_syms = link_info.emitrelocations || link_info.shared;
+    params.emit_stub_syms = (link_info.emitrelocations
+                            || bfd_link_pic (&link_info));
   if (pagesize == 0)
     pagesize = config.commonpagesize;
   params.pagesize_p2 = bfd_log2 (pagesize);
@@ -134,6 +136,8 @@ ppc_before_allocation (void)
 
   gld${EMULATION_NAME}_before_allocation ();
 
+  ppc_elf_maybe_strip_sdata_syms (&link_info);
+
   if (RELAXATION_ENABLED)
     params.branch_trampolines = 1;
 
@@ -169,10 +173,51 @@ ppc_before_allocation (void)
        params.branch_trampolines = 1;
     }
 
-  if (params.ppc476_workaround || params.branch_trampolines)
+  if (params.branch_trampolines
+      || params.ppc476_workaround
+      || params.pic_fixup > 0)
     ENABLE_RELAXATION;
 }
 
+/* Replaces default zero fill padding in executable sections with
+   "ba 0" instructions.  This works around the ppc476 icache bug if we
+   have a function pointer tail call near the end of a page, some
+   small amount of padding, then the function called at the beginning
+   of the next page.  If the "ba 0" is ever executed we should hit a
+   segv, so it's almost as good as an illegal instruction (zero).  */
+
+static void
+no_zero_padding (lang_statement_union_type *l)
+{
+  if (l->header.type == lang_padding_statement_enum
+      && l->padding_statement.size != 0
+      && l->padding_statement.output_section != NULL
+      && (l->padding_statement.output_section->flags & SEC_CODE) != 0
+      && l->padding_statement.fill->size == 0)
+    {
+      struct _ppc_fill_type
+      {
+       size_t size;
+       unsigned char data[4];
+      };
+      static struct _ppc_fill_type fill_be = { 4, {0x48, 0, 0, 2} };
+      static struct _ppc_fill_type fill_le = { 4, {2, 0, 0, 0x48} };
+
+      if (bfd_big_endian (link_info.output_bfd))
+       l->padding_statement.fill = (struct _fill_type *) &fill_be;
+      else
+       l->padding_statement.fill = (struct _fill_type *) &fill_le;
+    }
+}
+
+static void
+ppc_finish (void)
+{
+  if (params.ppc476_workaround)
+    lang_for_each_statement (no_zero_padding);
+  finish_default ();
+}
+
 EOF
 
 if grep -q 'ld_elf32_spu_emulation' ldemul-list.h; then
@@ -207,6 +252,7 @@ PARSE_AND_LIST_PROLOGUE=${PARSE_AND_LIST_PROLOGUE}'
 #define OPTION_NO_STUBSYMS             (OPTION_STUBSYMS + 1)
 #define OPTION_PPC476_WORKAROUND       (OPTION_NO_STUBSYMS + 1)
 #define OPTION_NO_PPC476_WORKAROUND    (OPTION_PPC476_WORKAROUND + 1)
+#define OPTION_NO_PICFIXUP             (OPTION_NO_PPC476_WORKAROUND + 1)
 '
 
 PARSE_AND_LIST_LONGOPTS=${PARSE_AND_LIST_LONGOPTS}'
@@ -223,6 +269,7 @@ fi
 PARSE_AND_LIST_LONGOPTS=${PARSE_AND_LIST_LONGOPTS}'
   { "ppc476-workaround", optional_argument, NULL, OPTION_PPC476_WORKAROUND },
   { "no-ppc476-workaround", no_argument, NULL, OPTION_NO_PPC476_WORKAROUND },
+  { "no-pic-fixup", no_argument, NULL, OPTION_NO_PICFIXUP },
 '
 
 PARSE_AND_LIST_OPTIONS=${PARSE_AND_LIST_OPTIONS}'
@@ -240,7 +287,8 @@ fi
 PARSE_AND_LIST_OPTIONS=${PARSE_AND_LIST_OPTIONS}'\
   --ppc476-workaround [=pagesize]\n\
                               Avoid a cache bug on ppc476.\n\
-  --no-ppc476-workaround      Disable workaround.\n"
+  --no-ppc476-workaround      Disable workaround.\n\
+  --no-pic-fixup              Don'\''t edit non-pic to pic.\n"
                   ));
 '
 
@@ -294,6 +342,10 @@ PARSE_AND_LIST_ARGS_CASES=${PARSE_AND_LIST_ARGS_CASES}'
     case OPTION_NO_PPC476_WORKAROUND:
       params.ppc476_workaround = 0;
       break;
+
+    case OPTION_NO_PICFIXUP:
+      params.pic_fixup = -1;
+      break;
 '
 
 # Put these extra ppc32elf routines in ld_${EMULATION_NAME}_emulation
@@ -303,3 +355,4 @@ if test -z "$VXWORKS_BASE_EM_FILE" ; then
   LDEMUL_AFTER_OPEN=ppc_after_open
 fi
 LDEMUL_BEFORE_ALLOCATION=ppc_before_allocation
+LDEMUL_FINISH=ppc_finish