MIPS/BFD: Do not redirect to discarded lazy binding stubs

Correct a MIPS/BFD linker issue with dynamic symbol and corresponding
GOT entry values being redirected to lazy binding stubs where the stubs
section has been discarded by assigning to the `/DISCARD/' output
section in the linker script used.  The issue manifests itself by the
values entered being relative to the absolute section, which is what any
discarded sections are internally assigned in the linker.

For the `stub-dynsym-2.s' piece of code included as a test case with
this change this issue results in the dynamic symbol table and the GOT
looking like:

Symbol table '.dynsym' contains 3 entries:
   Num:    Value  Size Type    Bind   Vis      Ndx Name
     0: 00000000     0 NOTYPE  LOCAL  DEFAULT  UND
     1: 00000010     0 FUNC    GLOBAL DEFAULT  UND bar
     2: 00000000     0 FUNC    GLOBAL DEFAULT  UND foo

Primary GOT:
 Canonical gp value: 00097ff0

 Reserved entries:
   Address     Access  Initial Purpose
  00090000 -32752(gp) 00000000 Lazy resolver
  00090004 -32748(gp) 80000000 Module pointer (GNU extension)

 Global entries:
   Address     Access  Initial Sym.Val. Type    Ndx Name
  00090008 -32744(gp) 00000010 00000010 FUNC    UND bar
  0009000c -32740(gp) 00000000 00000000 FUNC    UND foo

if assembled to regular MIPS code, or:

Symbol table '.dynsym' contains 3 entries:
   Num:    Value  Size Type    Bind   Vis      Ndx Name
     0: 00000000     0 NOTYPE  LOCAL  DEFAULT  UND
     1: 0000000d     0 FUNC    GLOBAL DEFAULT  UND bar
     2: 00000001     0 FUNC    GLOBAL DEFAULT  UND foo

Primary GOT:
 Canonical gp value: 00097ff0

 Reserved entries:
   Address     Access  Initial Purpose
  00090000 -32752(gp) 00000000 Lazy resolver
  00090004 -32748(gp) 80000000 Module pointer (GNU extension)

 Global entries:
   Address     Access  Initial Sym.Val. Type    Ndx Name
  00090008 -32744(gp) 0000000d 0000000d FUNC    UND bar
  0009000c -32740(gp) 00000001 00000001 FUNC    UND foo

if assembled to microMIPS code.  Symbol values and GOT entries record
the offset into the inexistent stubs section and the ISA bit rather than
zero, which would be the case if a lazy binding stub was not used for
other reasons, such as the value of the symbol being taken for a purpose
other than making a function call (e.g. an R_MIPS_GOT16 relocation).

Correct the issue by refraining from redirecting symbols to lazy binding
stubs if the stubs section is going to be discarded.

	bfd/
	* elfxx-mips.c (_bfd_mips_elf_adjust_dynamic_symbol): Don't set
	`->needs_lazy_stub' if the stubs output section is the absolute
	section.

	ld/
	* testsuite/ld-mips-elf/stub-dynsym-2.dd: New test.
	* testsuite/ld-mips-elf/stub-dynsym-2.gd: New test.
	* testsuite/ld-mips-elf/stub-dynsym-2.sd: New test.
	* testsuite/ld-mips-elf/stub-dynsym-discard-2.gd: New test.
	* testsuite/ld-mips-elf/stub-dynsym-discard-2.sd: New test.
	* testsuite/ld-mips-elf/stub-dynsym-micromips-2.dd: New test.
	* testsuite/ld-mips-elf/stub-dynsym-micromips-2.gd: New test.
	* testsuite/ld-mips-elf/stub-dynsym-micromips-2.sd: New test.
	* testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.dd: New
	test.
	* testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.gd: New
	test.
	* testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.sd: New
	test.
	* testsuite/ld-mips-elf/stub-dynsym-2.ld: New test linker
	script.
	* testsuite/ld-mips-elf/stub-dynsym-discard-2.ld: New test
	linker script.
	* testsuite/ld-mips-elf/mips-elf.exp: Run the new tests.

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 4b0454d8a8d5cd5a8010806edf09e11185f411a5..7e8cf8caf985cb9d6dd3ad926cec040963fa9f19 100644 (file)
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,9 @@
+2018-07-09  Maciej W. Rozycki  <macro@mips.com>
+
+       * elfxx-mips.c (_bfd_mips_elf_adjust_dynamic_symbol): Don't set
+       `->needs_lazy_stub' if the stubs output section is the absolute
+       section.
+
 2018-07-09  H.J. Lu  <hongjiu.lu@intel.com>
 
        PR ld/23388

diff --git a/bfd/elfxx-mips.c b/bfd/elfxx-mips.c
index c33b276ceff665518937c60dfcc1fd836954f34a..990e3a1e551c19a321ee64c24de3b6a1bf4965d4 100644 (file)
--- a/bfd/elfxx-mips.c
+++ b/bfd/elfxx-mips.c
@@ -9043,7 +9043,8 @@ _bfd_mips_elf_adjust_dynamic_symbol (struct bfd_link_info *info,
         the symbol to the stub location.  This is required to make
         function pointers compare as equal between the normal
         executable and the shared library.  */
-      if (!h->def_regular)
+      if (!h->def_regular
+         && !bfd_is_abs_section (htab->sstubs->output_section))
        {
          hmips->needs_lazy_stub = TRUE;
          htab->lazy_stub_count++;

diff --git a/ld/ChangeLog b/ld/ChangeLog
index c146f5cf9371bd0ce977c7620243f1eefbf3532c..7d382b9f4a10565f579e3f8ec014517b387c0aa5 100644 (file)
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,25 @@
+2018-07-09  Maciej W. Rozycki  <macro@mips.com>
+
+       * testsuite/ld-mips-elf/stub-dynsym-2.dd: New test.
+       * testsuite/ld-mips-elf/stub-dynsym-2.gd: New test.
+       * testsuite/ld-mips-elf/stub-dynsym-2.sd: New test.
+       * testsuite/ld-mips-elf/stub-dynsym-discard-2.gd: New test.
+       * testsuite/ld-mips-elf/stub-dynsym-discard-2.sd: New test.
+       * testsuite/ld-mips-elf/stub-dynsym-micromips-2.dd: New test.
+       * testsuite/ld-mips-elf/stub-dynsym-micromips-2.gd: New test.
+       * testsuite/ld-mips-elf/stub-dynsym-micromips-2.sd: New test.
+       * testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.dd: New
+       test.
+       * testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.gd: New
+       test.
+       * testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.sd: New
+       test.
+       * testsuite/ld-mips-elf/stub-dynsym-2.ld: New test linker
+       script.
+       * testsuite/ld-mips-elf/stub-dynsym-discard-2.ld: New test
+       linker script.
+       * testsuite/ld-mips-elf/mips-elf.exp: Run the new tests.
+
 2018-07-09  Maciej W. Rozycki  <macro@mips.com>
 
        * testsuite/lib/ld-lib.exp (run_dump_test): Call `unsupported'

diff --git a/ld/testsuite/ld-mips-elf/mips-elf.exp b/ld/testsuite/ld-mips-elf/mips-elf.exp
index ddd90f25ee26d107dfdd57a6bf53c09ba6dacedf..8b0594afc546734925ff0be4e5e95eb37258ec9d 100644 (file)
--- a/ld/testsuite/ld-mips-elf/mips-elf.exp
+++ b/ld/testsuite/ld-mips-elf/mips-elf.exp
@@ -807,6 +807,42 @@ if { $linux_gnu } {
                                      "stub-dynsym$suffix-1-$dynsym.d"]] \
                           "stub-dynsym$suffix-1-$dynsym"]]
        }
+       run_ld_link_tests [list \
+            [list \
+                "Retained stubs for dynsyms ($isa)" \
+                "-shared -melf32btsmip -T stub-dynsym-2.ld $lflag" "" \
+                "-EB $aflag -32 -KPIC" \
+                [list "stub-dynsym-2.s"] \
+                [list \
+                    [list \
+                       "objdump" \
+                       "-dz -j .MIPS.stubs" \
+                       "stub-dynsym$suffix-2.dd"] \
+                    [list \
+                       "readelf" \
+                       "--dyn-syms" \
+                       "stub-dynsym$suffix-2.sd"] \
+                    [list \
+                       "readelf" \
+                       "-A" \
+                       "stub-dynsym$suffix-2.gd"]] \
+                "stub-dynsym$suffix-2"] \
+            [list \
+                "Discarded stubs for dynsyms ($isa)" \
+                "-shared -melf32btsmip -T stub-dynsym-discard-2.ld $lflag" \
+                "" \
+                "-EB $aflag -32 -KPIC" \
+                [list "stub-dynsym-2.s"] \
+                [list \
+                    [list \
+                       "readelf" \
+                       "--dyn-syms" \
+                       "stub-dynsym-discard-2.sd"] \
+                    [list \
+                       "readelf" \
+                       "-A" \
+                       "stub-dynsym-discard-2.gd"]] \
+                "stub-dynsym-discard$suffix-2"]]
     }
 }
 

diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-2.dd b/ld/testsuite/ld-mips-elf/stub-dynsym-2.dd
new file mode 100644 (file)
index 0000000..6013a47
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-2.dd
@@ -0,0 +1,17 @@
+.*: +file format .*mips.*
+
+Disassembly of section \.MIPS\.stubs:
+
+000800ec <_MIPS_STUBS_>:
+   800ec:      8f998010        lw      t9,-32752\(gp\)
+   800f0:      03e07825        move    t7,ra
+   800f4:      0320f809        jalr    t9
+   800f8:      24180002        li      t8,2
+   800fc:      8f998010        lw      t9,-32752\(gp\)
+   80100:      03e07825        move    t7,ra
+   80104:      0320f809        jalr    t9
+   80108:      24180001        li      t8,1
+   8010c:      00000000        nop
+   80110:      00000000        nop
+   80114:      00000000        nop
+   80118:      00000000        nop

diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-2.gd b/ld/testsuite/ld-mips-elf/stub-dynsym-2.gd
new file mode 100644 (file)
index 0000000..411cdf1
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-2.gd
@@ -0,0 +1,12 @@
+Primary GOT:
+ Canonical gp value: 00097ff0
+
+ Reserved entries:
+   Address     Access  Initial Purpose
+  00090000 -32752\(gp\) 00000000 Lazy resolver
+  00090004 -32748\(gp\) 80000000 Module pointer \(GNU extension\)
+
+ Global entries:
+   Address     Access  Initial Sym\.Val\. Type    Ndx Name
+  00090008 -32744\(gp\) 000800fc 000800fc FUNC    UND bar
+  0009000c -32740\(gp\) 000800ec 000800ec FUNC    UND foo

diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-2.ld b/ld/testsuite/ld-mips-elf/stub-dynsym-2.ld
new file mode 100644 (file)
index 0000000..a385012
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-2.ld
@@ -0,0 +1,21 @@
+SECTIONS
+{
+  . = 0x80000;
+  .interp : { *(.interp) }
+  .hash : { *(.hash) }
+  .dynsym : { *(.dynsym) }
+  .dynstr : { *(.dynstr) }
+  .rel.dyn : { *(.rel.dyn) }
+  .MIPS.stubs : { *(.MIPS.stubs) }
+  .text : { *(.text) }
+
+  . = ALIGN (0x10000);
+  HIDDEN (_gp = . + 0x7ff0);
+  .got : { *(.got) }
+
+  .symtab : { *(.symtab) }
+  .strtab : { *(.strtab) }
+  .shstrtab : { *(.shstrtab) }
+
+  /DISCARD/ : { *(.reginfo) *(.MIPS.abiflags) *(.gnu.attributes) }
+}

diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-2.s b/ld/testsuite/ld-mips-elf/stub-dynsym-2.s
new file mode 100644 (file)
index 0000000..9c5f166
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-2.s
@@ -0,0 +1,2 @@
+       lw      $25,%call16(foo)($gp)
+       lw      $25,%call16(bar)($gp)

diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-2.sd b/ld/testsuite/ld-mips-elf/stub-dynsym-2.sd
new file mode 100644 (file)
index 0000000..4960ae7
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-2.sd
@@ -0,0 +1,5 @@
+Symbol table '\.dynsym' contains 3 entries:
+   Num:    Value  Size Type    Bind   Vis      Ndx Name
+     0: 00000000     0 NOTYPE  LOCAL  DEFAULT  UND 
+     1: 000800fc     0 FUNC    GLOBAL DEFAULT  UND bar
+     2: 000800ec     0 FUNC    GLOBAL DEFAULT  UND foo

diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-discard-2.gd b/ld/testsuite/ld-mips-elf/stub-dynsym-discard-2.gd
new file mode 100644 (file)
index 0000000..f56553a
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-discard-2.gd
@@ -0,0 +1,12 @@
+Primary GOT:
+ Canonical gp value: 00097ff0
+
+ Reserved entries:
+   Address     Access  Initial Purpose
+  00090000 -32752\(gp\) 00000000 Lazy resolver
+  00090004 -32748\(gp\) 80000000 Module pointer \(GNU extension\)
+
+ Global entries:
+   Address     Access  Initial Sym\.Val\. Type    Ndx Name
+  00090008 -32744\(gp\) 00000000 00000000 FUNC    UND bar
+  0009000c -32740\(gp\) 00000000 00000000 FUNC    UND foo

diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-discard-2.ld b/ld/testsuite/ld-mips-elf/stub-dynsym-discard-2.ld
new file mode 100644 (file)
index 0000000..e6d89bd
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-discard-2.ld
@@ -0,0 +1,22 @@
+SECTIONS
+{
+  . = 0x80000;
+  .interp : { *(.interp) }
+  .hash : { *(.hash) }
+  .dynsym : { *(.dynsym) }
+  .dynstr : { *(.dynstr) }
+  .rel.dyn : { *(.rel.dyn) }
+  .text : { *(.text) }
+
+  . = ALIGN (0x10000);
+  HIDDEN (_gp = . + 0x7ff0);
+  .got : { *(.got) }
+
+  .symtab : { *(.symtab) }
+  .strtab : { *(.strtab) }
+  .shstrtab : { *(.shstrtab) }
+
+  /DISCARD/ : {
+    *(.reginfo) *(.MIPS.abiflags) *(.MIPS.stubs) *(.gnu.attributes)
+  }
+}

diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-discard-2.sd b/ld/testsuite/ld-mips-elf/stub-dynsym-discard-2.sd
new file mode 100644 (file)
index 0000000..f78f939
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-discard-2.sd
@@ -0,0 +1,5 @@
+Symbol table '\.dynsym' contains 3 entries:
+   Num:    Value  Size Type    Bind   Vis      Ndx Name
+     0: 00000000     0 NOTYPE  LOCAL  DEFAULT  UND 
+     1: 00000000     0 FUNC    GLOBAL DEFAULT  UND bar
+     2: 00000000     0 FUNC    GLOBAL DEFAULT  UND foo

diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-2.dd b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-2.dd
new file mode 100644 (file)
index 0000000..7c3bf25
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-2.dd
@@ -0,0 +1,16 @@
+.*: +file format .*mips.*
+
+Disassembly of section \.MIPS\.stubs:
+
+000800ec <_MIPS_STUBS_>:
+   800ec:      ff3c 8010       lw      t9,-32752\(gp\)
+   800f0:      0dff            move    t7,ra
+   800f2:      45d9            jalr    t9
+   800f4:      3300 0002       li      t8,2
+   800f8:      ff3c 8010       lw      t9,-32752\(gp\)
+   800fc:      0dff            move    t7,ra
+   800fe:      45d9            jalr    t9
+   80100:      3300 0001       li      t8,1
+   80104:      0000 0000       nop
+   80108:      0000 0000       nop
+   8010c:      0000 0000       nop

diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-2.gd b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-2.gd
new file mode 100644 (file)
index 0000000..2691d1d
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-2.gd
@@ -0,0 +1,12 @@
+Primary GOT:
+ Canonical gp value: 00097ff0
+
+ Reserved entries:
+   Address     Access  Initial Purpose
+  00090000 -32752\(gp\) 00000000 Lazy resolver
+  00090004 -32748\(gp\) 80000000 Module pointer \(GNU extension\)
+
+ Global entries:
+   Address     Access  Initial Sym\.Val\. Type    Ndx Name
+  00090008 -32744\(gp\) 000800f9 000800f9 FUNC    UND bar
+  0009000c -32740\(gp\) 000800ed 000800ed FUNC    UND foo

diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-2.sd b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-2.sd
new file mode 100644 (file)
index 0000000..d0b8d49
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-2.sd
@@ -0,0 +1,5 @@
+Symbol table '\.dynsym' contains 3 entries:
+   Num:    Value  Size Type    Bind   Vis      Ndx Name
+     0: 00000000     0 NOTYPE  LOCAL  DEFAULT  UND 
+     1: 000800f9     0 FUNC    GLOBAL DEFAULT  UND bar
+     2: 000800ed     0 FUNC    GLOBAL DEFAULT  UND foo

diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.dd b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.dd
new file mode 100644 (file)
index 0000000..8c33741
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.dd
@@ -0,0 +1,17 @@
+.*: +file format .*mips.*
+
+Disassembly of section \.MIPS\.stubs:
+
+000800ec <_MIPS_STUBS_>:
+   800ec:      ff3c 8010       lw      t9,-32752\(gp\)
+   800f0:      001f 7a90       move    t7,ra
+   800f4:      03f9 0f3c       jalr    t9
+   800f8:      3300 0002       li      t8,2
+   800fc:      ff3c 8010       lw      t9,-32752\(gp\)
+   80100:      001f 7a90       move    t7,ra
+   80104:      03f9 0f3c       jalr    t9
+   80108:      3300 0001       li      t8,1
+   8010c:      0000 0000       nop
+   80110:      0000 0000       nop
+   80114:      0000 0000       nop
+   80118:      0000 0000       nop

diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.gd b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.gd
new file mode 100644 (file)
index 0000000..1ebc071
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.gd
@@ -0,0 +1,12 @@
+Primary GOT:
+ Canonical gp value: 00097ff0
+
+ Reserved entries:
+   Address     Access  Initial Purpose
+  00090000 -32752\(gp\) 00000000 Lazy resolver
+  00090004 -32748\(gp\) 80000000 Module pointer \(GNU extension\)
+
+ Global entries:
+   Address     Access  Initial Sym\.Val\. Type    Ndx Name
+  00090008 -32744\(gp\) 000800fd 000800fd FUNC    UND bar
+  0009000c -32740\(gp\) 000800ed 000800ed FUNC    UND foo

diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.sd b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.sd
new file mode 100644 (file)
index 0000000..860fd48
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.sd
@@ -0,0 +1,5 @@
+Symbol table '\.dynsym' contains 3 entries:
+   Num:    Value  Size Type    Bind   Vis      Ndx Name
+     0: 00000000     0 NOTYPE  LOCAL  DEFAULT  UND 
+     1: 000800fd     0 FUNC    GLOBAL DEFAULT  UND bar
+     2: 000800ed     0 FUNC    GLOBAL DEFAULT  UND foo