PR gas/20649: MIPS: Fix GOT16/LO16 reloc pairing with comdat sections

Correct a regression from commit 8614eeee67f9 ("Traditional MIPS
patches"), <https://sourceware.org/ml/binutils/2000-07/msg00018.html>,
which caused symbols in linkonce or what is these days known as comdat
sections to be treated as external for the purpose of PIC relocation
generation even if their binding remains STB_LOCAL.  This in turn
disabled GOT16/LO16 relocation pairing with references to such symbols,
as no complementing LO16 relocation is expected for external GOT16
references in the o32 ABI, which ultimately leads to link errors, e.g.:

ld: comdat-reloc.o: Can't find matching LO16 reloc against `foo' for R_MIPS_GOT16 at 0x24 in section `.text.bar[bar]'

as with the LD test case included with this change.

Revert the special case for symbols in comdat sections then, making code
actually match `adjust_reloc_syms' as indicated in its explanatory
comment, and adjust calling code accordingly.  Also bring back the
corresponding description of what now is `s_is_linkonce', lost with
commit 5f0fe04bc550 ("Improved MIPS16/MIPS32 code intermixing for
gas."), <https://www.sourceware.org/ml/binutils/2006-07/msg00039.html>.

	gas/
	PR gas/20649
	* config/tc-mips.c (pic_need_relax): Don't check for linkonce
	symbols, remove the `segtype' parameter.
	(mips_frob_file, md_estimate_size_before_relax): Adjust
	accordingly.
	(s_is_linkonce): Add an explanatory comment.
	* testsuite/gas/mips/comdat-reloc.d: New test.
	* testsuite/gas/mips/comdat-reloc.s: New test source.
	* testsuite/gas/mips/mips.exp: Run the new test.

	ld/
	PR gas/20649
	* testsuite/ld-mips-elf/mips-elf.exp: Add PIC comdat GOT16/LO16
	relocation pairing link test.

diff --git a/gas/ChangeLog b/gas/ChangeLog
index a4ee544b877494ee3a7e33b73ae0dc87e251304e..d515f3bfc3997205863d9f0340eb95ab6aba126c 100644 (file)
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,15 @@
+2017-01-18  Maciej W. Rozycki  <macro@imgtec.com>
+
+       PR gas/20649
+       * config/tc-mips.c (pic_need_relax): Don't check for linkonce
+       symbols, remove the `segtype' parameter.
+       (mips_frob_file, md_estimate_size_before_relax): Adjust
+       accordingly.
+       (s_is_linkonce): Add an explanatory comment.
+       * testsuite/gas/mips/comdat-reloc.d: New test.
+       * testsuite/gas/mips/comdat-reloc.s: New test source.
+       * testsuite/gas/mips/mips.exp: Run the new test.
+
 2017-01-18  Szabolcs Nagy  <szabolcs.nagy@arm.com>
 
        * testsuite/gas/arm/armv8_3-a-simd.s: Add vcmla tests.

diff --git a/gas/config/tc-mips.c b/gas/config/tc-mips.c
index 79958c83b6d4341ce69e3054dd7a3e3df5127d79..1487e73b856d3617a4d2e9049002d464177d4165 100644 (file)
--- a/gas/config/tc-mips.c
+++ b/gas/config/tc-mips.c
@@ -1353,7 +1353,7 @@ static void s_mips_stab (int);
 static void s_mips_weakext (int);
 static void s_mips_file (int);
 static void s_mips_loc (int);
-static bfd_boolean pic_need_relax (symbolS *, asection *);
+static bfd_boolean pic_need_relax (symbolS *);
 static int relaxed_branch_length (fragS *, asection *, int);
 static int relaxed_micromips_16bit_branch_length (fragS *, asection *, int);
 static int relaxed_micromips_32bit_branch_length (fragS *, asection *, int);
@@ -4267,6 +4267,8 @@ mips_move_text_labels (void)
   mips_move_labels (seg_info (now_seg)->label_list, TRUE);
 }
 
+/* Duplicate the test for LINK_ONCE sections as in `adjust_reloc_syms'.  */
+
 static bfd_boolean
 s_is_linkonce (symbolS *sym, segT from_seg)
 {
@@ -14895,7 +14897,7 @@ mips_frob_file (void)
         constants; we'll report an error for those later.  */
       if (got16_reloc_p (l->fixp->fx_r_type)
          && !(l->fixp->fx_addsy
-              && pic_need_relax (l->fixp->fx_addsy, l->seg)))
+              && pic_need_relax (l->fixp->fx_addsy)))
        continue;
 
       /* Check quickly whether the next fixup happens to be a matching %lo.  */
@@ -17115,7 +17117,7 @@ nopic_need_relax (symbolS *sym, int before_relaxing)
 /* Return true if the given symbol should be considered local for SVR4 PIC.  */
 
 static bfd_boolean
-pic_need_relax (symbolS *sym, asection *segtype)
+pic_need_relax (symbolS *sym)
 {
   asection *symsec;
 
@@ -17140,7 +17142,6 @@ pic_need_relax (symbolS *sym, asection *segtype)
   return (!bfd_is_und_section (symsec)
          && !bfd_is_abs_section (symsec)
          && !bfd_is_com_section (symsec)
-         && !s_is_linkonce (sym, segtype)
          /* A global or weak symbol is treated as external.  */
          && (!S_IS_WEAK (sym) && !S_IS_EXTERNAL (sym)));
 }
@@ -17579,7 +17580,7 @@ md_estimate_size_before_relax (fragS *fragp, asection *segtype)
   if (mips_pic == NO_PIC)
     change = nopic_need_relax (fragp->fr_symbol, 0);
   else if (mips_pic == SVR4_PIC)
-    change = pic_need_relax (fragp->fr_symbol, segtype);
+    change = pic_need_relax (fragp->fr_symbol);
   else if (mips_pic == VXWORKS_PIC)
     /* For vxworks, GOT16 relocations never have a corresponding LO16.  */
     change = 0;

diff --git a/gas/testsuite/gas/mips/comdat-reloc.d b/gas/testsuite/gas/mips/comdat-reloc.d
new file mode 100644 (file)
index 0000000..12d092a
--- /dev/null
+++ b/gas/testsuite/gas/mips/comdat-reloc.d
@@ -0,0 +1,31 @@
+#readelf: -gr
+#name: MIPS ELF o32 PIC comdat GOT16/LO16 relocation pairing
+#as: -32 -mno-pdr
+
+# Make sure the orphan GOT16 relocation is paired with LO16 for a local
+# symbol in a comdat section, i.e. rather than this:
+#
+# 00000014  00000509 R_MIPS_GOT16      00000000   foo
+# 00000020  00000506 R_MIPS_LO16       00000000   foo
+# 0000001c  00000509 R_MIPS_GOT16      00000000   foo
+#
+# we have this:
+#
+# 00000014  00000509 R_MIPS_GOT16      00000000   foo
+# 00000024  00000509 R_MIPS_GOT16      00000000   foo
+# 0000001c  00000506 R_MIPS_LO16       00000000   foo
+
+#...
+COMDAT group section \[.....\] `\.group' \[bar\] contains .+ sections:
+   \[Index\]    Name
+   \[.....\]   \.text\.foo
+   \[.....\]   \.text\.bar
+#...
+Relocation section '\.rel\.text\.bar' at offset .+ contains .+ entries:
+ Offset     Info    Type            Sym\.Value  Sym\. Name
+00000000  ......05 R_MIPS_HI16       00000000   _gp_disp
+00000004  ......06 R_MIPS_LO16       00000000   _gp_disp
+00000014  ......09 R_MIPS_GOT16      00000000   foo
+00000024  ......09 R_MIPS_GOT16      00000000   foo
+0000001c  ......06 R_MIPS_LO16       00000000   foo
+#pass

diff --git a/gas/testsuite/gas/mips/comdat-reloc.s b/gas/testsuite/gas/mips/comdat-reloc.s
new file mode 100644 (file)
index 0000000..be972bd
--- /dev/null
+++ b/gas/testsuite/gas/mips/comdat-reloc.s
@@ -0,0 +1,38 @@
+       .abicalls
+
+       .section        .text.foo, "axG", @progbits, bar, comdat
+       .align  2
+       .ent    foo
+       .type   foo, @function
+foo:
+       .frame  $sp, 0, $31
+       .mask   0x00000000, 0
+       .fmask  0x00000000, 0
+       jr      $31
+       .end    foo
+       .size   foo, . - foo
+
+       .section        .text.bar, "axG", @progbits, bar, comdat
+       .align  2
+       .globl  bar
+       .ent    bar
+       .type   bar, @function
+bar:
+       .frame  $sp, 0, $31
+       .mask   0x00000000, 0
+       .fmask  0x00000000, 0
+       .set    noreorder
+       .cpload $25
+       .set    reorder
+       beqz    $4, 1f
+       .set    noreorder
+       lw      $2, %got(foo)($28)
+0:
+       jr      $31
+        addiu  $2, $2, %lo(foo)
+1:
+       b       0b
+        lw     $2, %got(foo)($28)
+       .set    reorder
+       .end    bar
+       .size   bar, . - bar

diff --git a/gas/testsuite/gas/mips/mips.exp b/gas/testsuite/gas/mips/mips.exp
index 6a1aa6c1deefd3394f4526aa65733ea3c1d0b834..106bd7b6c2c41f320ebb1f496dba060ad5012b40 100644 (file)
--- a/gas/testsuite/gas/mips/mips.exp
+++ b/gas/testsuite/gas/mips/mips.exp
@@ -1168,6 +1168,8 @@ if { [istarget mips*-*-vxworks*] } {
     }
     run_list_test_arches "elf-rel30" "-32" [mips_arch_list_all]
 
+    run_dump_test "comdat-reloc"
+
     run_dump_test "${tmips}mips${el}16-e"
     run_dump_test "${tmips}mips${el}16-f"
 

diff --git a/ld/ChangeLog b/ld/ChangeLog
index ec562dcfde5dbc20de9aa53ec828fad32cb63a87..e505c84f358b1765fdcbaf169af6c89d0eea5ad1 100644 (file)
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,9 @@
+2017-01-18  Maciej W. Rozycki  <macro@imgtec.com>
+
+       PR gas/20649
+       * testsuite/ld-mips-elf/mips-elf.exp: Add PIC comdat GOT16/LO16
+       relocation pairing link test.
+
 2017-01-17  Dimitar Dimitrov  <dimitar@dinux.eu>
 
        * testsuite/ld-unique/unique.exp: Filter shared lib cases in

diff --git a/ld/testsuite/ld-mips-elf/mips-elf.exp b/ld/testsuite/ld-mips-elf/mips-elf.exp
index 994670851338f32a8fb63c0420d1eb0bde0daf47..5639c8417fbc6aba1780c20b8a0eb4d91b0827fb 100644 (file)
--- a/ld/testsuite/ld-mips-elf/mips-elf.exp
+++ b/ld/testsuite/ld-mips-elf/mips-elf.exp
@@ -573,6 +573,13 @@ if { $has_newabi } {
 }
 
 run_dump_test "reloc-local-overflow" [list [list ld $abi_ldflags(o32)]]
+run_ld_link_tests [list \
+    [list \
+       "MIPS link ELF o32 PIC comdat GOT16/LO16 relocation pairing" \
+       "$abi_ldflags(o32) -e bar" "" "$abi_asflags(o32) -mno-pdr" \
+       "../../../gas/testsuite/gas/mips/comdat-reloc.s" \
+       {} \
+       "comdat-reloc"]]
 
 if {$has_newabi && $linux_gnu} {
     run_dump_test "eh-frame1-n32"