ELF/LD: Avoid producing hidden and internal dynamic symbols

Always turn hidden and internal symbols which have a dynamic index into
local ones.  This is required by the the ELF gABI[1]:

"A hidden symbol contained in a relocatable object must be either
removed or converted to STB_LOCAL binding by the link-editor when the
relocatable object is included in an executable file or shared object."

"An internal symbol contained in a relocatable object must be either
removed or converted to STB_LOCAL binding by the link-editor when the
relocatable object is included in an executable file or shared object."

The ELF linker usually respects this requirement, however in the case
where a dynamic symbol has been preallocated due to a reference of the
default export class aka visibility from the object being linked, and
then merged with a hidden or internal symbol definition from within the
same object, then the original export class is carried over to the
output dynamic symbol table, because while merging the generic ELF
linker only converts affected dynamic symbols to local when they are
defined or referenced by the object being linked and a dynamic object
involved in the link both at a time.

The dynamic symbol produced confuses then the dynamic loader at the run
time -- the hidden or internal export class is ignored and the symbol
follows preemption rules as with the default export class.

In the MIPS target it happens when `mips_elf_record_global_got_symbol'
creates a dynamic symbol when a call relocation is encountered.
Additionally if the undefined symbol referred by such a relocation does
specify the intended export class, then a local dynamic symbol is
created instead, which is harmless and allowed, but useless.  Normally
no local dynamic symbols are created, except for a single dummy one at
the beginning.

Correct the problem by removing the extra check for a dynamic symbol
being defined or referenced by the object being linked and a dynamic
object involved in the link both at a time.  The test cases included
cover the internal and hidden symbol cases, as well as a protected
symbol for a reference, the handling of which is unchanged by this fix.
Both cases described above are covered, that is where an internal or
hidden dynamic symbol is produced and where a local one is.

NB this change affects CRIS results where some symbols in the static
table produced in a final link are now converted from STV_HIDDEN to
STB_LOCAL.  This happens whenever the `elf_backend_hide_symbol' handler
is called, so the affected symbols must have been chosen for entering
into the dynamic symbol table, except in these test cases no such symbol
table is produced.  In fully linked binaries the static symbol table is
only used for debugging though, so such a change is fine.

References:

[1] "System V Application Binary Interface - DRAFT - 24 April 2001",
    The Santa Cruz Operation, Inc., "Symbol Table",
    <http://www.sco.com/developers/gabi/2001-04-24/ch4.symtab.html>

	bfd/
	PR ld/19908
	* elflink.c (elf_link_add_object_symbols): Always turn hidden
	and internal symbols which have a dynamic index into local
	ones.

	ld/
	PR ld/19908
	* testsuite/ld-cris/tls-e-20.d: Adjust for hidden symbol
	handling fix.
	* testsuite/ld-cris/tls-e-20a.d: Likewise.
	* testsuite/ld-cris/tls-e-21.d: Likewise.
	* testsuite/ld-cris/tls-e-23.d: Likewise.
	* testsuite/ld-cris/tls-e-80.d: Likewise.
	* testsuite/ld-cris/tls-gd-3h.d: Likewise.
	* testsuite/ld-cris/tls-leie-19.d: Likewise.
	* testsuite/ld-mips-elf/export-class-ref-lib.sd: New test.
	* testsuite/ld-mips-elf/export-hidden-ref.sd: New test.
	* testsuite/ld-mips-elf/export-internal-ref.sd: New test.
	* testsuite/ld-mips-elf/export-protected-ref.sd: New test.
	* testsuite/ld-mips-elf/export-class-ref-f0.s: New test source.
	* testsuite/ld-mips-elf/export-class-ref-f1.s: New test source.
	* testsuite/ld-mips-elf/export-class-ref-f2.s: New test source.
	* testsuite/ld-mips-elf/mips-elf.exp: Run the new tests.

9 files changed, 136 insertions, 0 deletions

diff --git a/ld/testsuite/ld-mips-elf/export-class-ref-f0.s b/ld/testsuite/ld-mips-elf/export-class-ref-f0.s
new file mode 100644
index 0000000..675996d
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/export-class-ref-f0.s
@@ -0,0 +1,37 @@
+	.abicalls
+	.text
+
+	.if	refv == 3
+	.protected f1
+	.elseif	refv == 2
+	.hidden	f1
+	.elseif	refv == 1
+	.internal f1
+	.endif
+
+	.globl	f0
+	.ent	f0
+f0:
+	.frame	$sp, 32, $31
+	.mask	0x80000000, -4
+	.fmask	0x00000000, 0
+	.set	noreorder
+	.cpload	$25
+	.set	reorder
+	addiu	$sp, $sp, -32
+	sw	$31, 28($sp)
+	.cprestore 16
+
+	lw	$25, %call16(f1)($28)
+	jalr	$25
+	lw	$28, 16($sp)
+
+	lw	$25, %call16(f2)($28)
+	jalr	$25
+	lw	$28, 16($sp)
+
+	move	$2, $0
+	lw	$31, 28($sp)
+	addiu	$sp, $sp, 32
+	jr	$31
+	.end	f0
diff --git a/ld/testsuite/ld-mips-elf/export-class-ref-f1.s b/ld/testsuite/ld-mips-elf/export-class-ref-f1.s
new file mode 100644
index 0000000..299278d
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/export-class-ref-f1.s
@@ -0,0 +1,18 @@
+	.abicalls
+	.text
+
+	.globl	f1
+	.if	defv == 3
+	.protected f1
+	.elseif	defv == 2
+	.hidden	f1
+	.elseif	defv == 1
+	.internal f1
+	.endif
+	.ent	f1
+f1:
+	.frame	$sp, 0, $31
+	.mask	0x00000000, 0
+	.fmask	0x00000000, 0
+	jr	$31
+	.end	f1
diff --git a/ld/testsuite/ld-mips-elf/export-class-ref-f2.s b/ld/testsuite/ld-mips-elf/export-class-ref-f2.s
new file mode 100644
index 0000000..deecdd2
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/export-class-ref-f2.s
@@ -0,0 +1,20 @@
+	.abicalls
+	.text
+
+	.globl	f1
+	.ent	f1
+f1:
+	.frame	$sp, 0, $31
+	.mask	0x00000000, 0
+	.fmask	0x00000000, 0
+	jr	$31
+	.end	f1
+
+	.globl	f2
+	.ent	f2
+f2:
+	.frame	$sp, 0, $31
+	.mask	0x00000000, 0
+	.fmask	0x00000000, 0
+	jr	$31
+	.end	f2
diff --git a/ld/testsuite/ld-mips-elf/export-class-ref-lib.sd b/ld/testsuite/ld-mips-elf/export-class-ref-lib.sd
new file mode 100644
index 0000000..26b3e38
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/export-class-ref-lib.sd
@@ -0,0 +1,6 @@
+# Make sure `f1' is present in the dynamic symbol table, e.g.:
+#    Num:    Value  Size Type    Bind   Vis      Ndx Name
+#      6: 000002d0     8 FUNC    GLOBAL DEFAULT    7 f1
+#...
+ *[0-9]+: +[0-9a-f]+ +[0-9]+ FUNC +GLOBAL +DEFAULT +[0-9]+ f1
+#pass
diff --git a/ld/testsuite/ld-mips-elf/export-hidden-ref.sd b/ld/testsuite/ld-mips-elf/export-hidden-ref.sd
new file mode 100644
index 0000000..b1d6246
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/export-hidden-ref.sd
@@ -0,0 +1,7 @@
+# Make sure no hidden symbol is present in the dynamic symbol table, e.g.:
+#    Num:    Value  Size Type    Bind   Vis      Ndx Name
+#      6: 004003f0     8 FUNC    GLOBAL HIDDEN     8 f1
+#failif
+#...
+.+ +HIDDEN +.+ +f1
+#pass
diff --git a/ld/testsuite/ld-mips-elf/export-internal-ref.sd b/ld/testsuite/ld-mips-elf/export-internal-ref.sd
new file mode 100644
index 0000000..4851543
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/export-internal-ref.sd
@@ -0,0 +1,7 @@
+# Make sure no internal symbol is present in the dynamic symbol table, e.g.:
+#    Num:    Value  Size Type    Bind   Vis      Ndx Name
+#      6: 004003f0     8 FUNC    GLOBAL INTERNAL   8 f1
+#failif
+#...
+.+ +INTERNAL +.+ +f1
+#pass
diff --git a/ld/testsuite/ld-mips-elf/export-local-ref.sd b/ld/testsuite/ld-mips-elf/export-local-ref.sd
new file mode 100644
index 0000000..4ee4a42
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/export-local-ref.sd
@@ -0,0 +1,7 @@
+# Make sure no local symbol is present in the dynamic symbol table, e.g.:
+#    Num:    Value  Size Type    Bind   Vis      Ndx Name
+#      6: 004003f0     8 FUNC    LOCAL  DEFAULT    8 f1
+#failif
+#...
+.+ +LOCAL +.+ +f1
+#pass
diff --git a/ld/testsuite/ld-mips-elf/export-protected-ref.sd b/ld/testsuite/ld-mips-elf/export-protected-ref.sd
new file mode 100644
index 0000000..af2cb98
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/export-protected-ref.sd
@@ -0,0 +1,6 @@
+# Make sure a protected symbol is present in the dynamic symbol table, e.g.:
+#    Num:    Value  Size Type    Bind   Vis      Ndx Name
+#      6: 004003f0     8 FUNC    GLOBAL PROTECTED    8 f1
+#...
+ *[0-9]+: +[0-9a-f]+ +[0-9]+ FUNC +GLOBAL +PROTECTED +[0-9]+ f1
+#pass
diff --git a/ld/testsuite/ld-mips-elf/mips-elf.exp b/ld/testsuite/ld-mips-elf/mips-elf.exp
index c5ce5bc..4467719 100644
--- a/ld/testsuite/ld-mips-elf/mips-elf.exp
+++ b/ld/testsuite/ld-mips-elf/mips-elf.exp
@@ -899,3 +899,31 @@ if { $linux_gnu } {
 	    n32 -1 1 umips
     }
 }
+
+# PR ld/19908 export class tests.
+if { $linux_gnu } {
+    run_ld_link_tests [list \
+	[list "Shared library for MIPS export class symbol reference tests" \
+	      "$abi_ldflags(o32) -shared" "" \
+	      "$abi_asflags(o32)" \
+	      { export-class-ref-f2.s } \
+	      { { readelf --dyn-syms export-class-ref-lib.sd } } \
+	      "export-class-ref-lib.so"]]
+    foreach { class flag } { internal 1 hidden 2 protected 3 } {
+	run_ld_link_tests [list \
+	    [list "MIPS $class symbol reference test 1" \
+		  "$abi_ldflags(o32) -e f0" "tmpdir/export-class-ref-lib.so" \
+		  "$abi_asflags(o32) --defsym defv=$flag" \
+		  { export-class-ref-f0.s export-class-ref-f1.s } \
+		  [list [list readelf --dyn-syms export-$class-ref.sd] \
+			[list readelf --dyn-syms export-local-ref.sd]] \
+		  "export-$class-ref"] \
+	    [list "MIPS $class symbol reference test 2" \
+		  "$abi_ldflags(o32) -e f0" "tmpdir/export-class-ref-lib.so" \
+		  "$abi_asflags(o32) --defsym defv=$flag --defsym refv=$flag" \
+		  { export-class-ref-f0.s export-class-ref-f1.s } \
+		  [list [list readelf --dyn-syms export-$class-ref.sd] \
+			[list readelf --dyn-syms export-local-ref.sd]] \
+		  "export-$class-ref"]]
+    }
+}