PR ld/20828: Move symbol version processing ahead of GC symbol sweep

Complement commit b531344c34b0 ("PR ld/20828: Reorder the symbol sweep
stage of section GC") and commit 81ff47b3a546 ("PR ld/20828: Fix linker
script symbols wrongly forced local with section GC") and move symbol
version processing ahead of the symbol sweep stage of section GC, all in
`bfd_elf_size_dynamic_sections', so that version symbols created stay in
the global scope and are not output as local symbols to the dynamic
symbol table in the presence of corresponding symbol definitions pulled
from a DSO involved in a link.

Consolidate the whole of symbol version processing into a single block
from all parts scattered across the function and rearranging the local
variables used as necessary, however leaving the setting of dynamic
entries associated with the DT_VERDEF, DT_VERDEFNUM, DT_VERNEED and
DT_VERNEEDNUM tags and the SEC_EXCLUDE flag for unused `.gnu.version'
section in the original places.

With the rearrangement of code blocks `Elf_Internal_Verneed *t' would
shadow the previous definition of `struct bfd_elf_version_tree *t', so
rename the former variable to `vn'.

	bfd/
	PR ld/20828
	* elflink.c (bfd_elf_size_dynamic_sections): Move symbol version
	processing ahead of the call to `elf_gc_sweep_symbol'.

	ld/
	PR ld/20828
	* testsuite/ld-elf/pr20828-d.sd: New test.
	* testsuite/ld-elf/pr20828-e.sd: New test.
	* testsuite/ld-elf/pr20828-v.od: New test.
	* testsuite/ld-elf/pr20828-v.ver: New test version script.
	* testsuite/ld-elf/pr20828-v.ld: New test linker script.
	* testsuite/ld-elf/pr20828.ld: Add `.gnu.version' and
	`.gnu.version_d'.
	* testsuite/ld-elf/shared.exp: Run the new tests.

8 files changed, 94 insertions, 1 deletions

diff --git a/ld/testsuite/ld-elf/pr20828-d.sd b/ld/testsuite/ld-elf/pr20828-d.sd
new file mode 100644
index 0000000..a5777a4
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr20828-d.sd
@@ -0,0 +1,9 @@
+# Make sure `vdata' is global rather than local in the dynamic symbol table,
+# e.g.:
+#    Num:    Value  Size Type    Bind   Vis      Ndx Name
+#      1: 00000000     0 OBJECT  GLOBAL DEFAULT  ABS vdata
+# vs:
+#      1: 00000000     0 OBJECT  LOCAL  DEFAULT  ABS vdata
+#...
+ *[0-9]+: +[0-9a-f]+ +0 +OBJECT +GLOBAL +DEFAULT +ABS +vdata
+#pass
diff --git a/ld/testsuite/ld-elf/pr20828-e.sd b/ld/testsuite/ld-elf/pr20828-e.sd
new file mode 100644
index 0000000..893fb31
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr20828-e.sd
@@ -0,0 +1,9 @@
+# Make sure `edata' is global rather than local in the dynamic symbol table,
+# e.g.:
+#    Num:    Value  Size Type    Bind   Vis      Ndx Name
+#      1: 00000000     0 NOTYPE  GLOBAL DEFAULT    1 edata@@vdata
+# vs:
+#      1: 00000000     0 NOTYPE  LOCAL  DEFAULT    1 edata@@vdata
+#...
+ *[0-9]+: +[0-9a-f]+ +0 +NOTYPE +GLOBAL +DEFAULT +[0-9]+ +edata@@vdata
+#pass
diff --git a/ld/testsuite/ld-elf/pr20828-v.ld b/ld/testsuite/ld-elf/pr20828-v.ld
new file mode 100644
index 0000000..cdba796
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr20828-v.ld
@@ -0,0 +1,18 @@
+SECTIONS
+{
+  .hash : { *(.hash) }
+  .dynsym : { *(.dynsym) }
+  .dynstr : { *(.dynstr) }
+  .gnu.version : { *(.gnu.version) }
+  .gnu.version_d : { *(.gnu.version_d) }
+  .text : { *(.text) }
+  .dynamic : { *(.dynamic) }
+  .data : { *(.data) }
+  .symtab : { *(.symtab) }
+  .strtab : { *(.strtab) }
+  .shstrtab : { *(.shstrtab) }
+  .plt : { *(.plt) }
+  .got.plt : { *(.got.plt) }
+  .got : { *(.got) }
+  /DISCARD/ : { *(*) }
+}
diff --git a/ld/testsuite/ld-elf/pr20828-v.od b/ld/testsuite/ld-elf/pr20828-v.od
new file mode 100644
index 0000000..12953b9
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr20828-v.od
@@ -0,0 +1,5 @@
+#...
+Version definitions:
+1 0x01 0x0b2e1e3([12]) pr20828-v-\1
+2 0x00 0x0cc85d2f ver_foo
+#pass
diff --git a/ld/testsuite/ld-elf/pr20828-v.s b/ld/testsuite/ld-elf/pr20828-v.s
new file mode 100644
index 0000000..363e09f
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr20828-v.s
@@ -0,0 +1,13 @@
+	.text
+	.globl	new_foo
+	.type	new_foo, %function
+new_foo:
+	.size	new_foo, . - new_foo
+	.symver	new_foo, foo@@ver_foo
+
+	.data
+	.globl	bar
+	.type	bar, %object
+bar:
+	.dc.a	foo
+	.size	bar, . - bar
diff --git a/ld/testsuite/ld-elf/pr20828-v.ver b/ld/testsuite/ld-elf/pr20828-v.ver
new file mode 100644
index 0000000..addc0f0
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr20828-v.ver
@@ -0,0 +1 @@
+vdata { global: edata; local: *; };
diff --git a/ld/testsuite/ld-elf/pr20828.ld b/ld/testsuite/ld-elf/pr20828.ld
index 0166f52..034887d 100644
--- a/ld/testsuite/ld-elf/pr20828.ld
+++ b/ld/testsuite/ld-elf/pr20828.ld
@@ -10,6 +10,8 @@ SECTIONS
   .hash : { *(.hash) }
   .dynsym : { *(.dynsym) }
   .dynstr : { *(.dynstr) }
+  .gnu.version : { *(.gnu.version) }
+  .gnu.version_d : { *(.gnu.version_d) }
   .shstrtab : { *(.shstrtab) }
   .symtab : { *(.symtab) }
   .strtab : { *(.strtab) }
diff --git a/ld/testsuite/ld-elf/shared.exp b/ld/testsuite/ld-elf/shared.exp
index 3b8ab18..41fb2ba 100644
--- a/ld/testsuite/ld-elf/shared.exp
+++ b/ld/testsuite/ld-elf/shared.exp
@@ -50,6 +50,8 @@ if [istarget "tic6x-*-*"] {
 # - the shared library symbols have been swept in section garbage collection.
 # Verify that the symbols are global rather than local and that a version
 # script adjusts them accordingly.
+# Also verify that a version definition supplied by an object rather than
+# a version script and forcibly exported is unaffected by section GC.
 if { [check_gc_sections_available] } {
     run_ld_link_tests [list \
 	[list \
@@ -77,7 +79,41 @@ if { [check_gc_sections_available] } {
 	    {pr20828.s} \
 	    {{readelf --dyn-syms pr20828-b.sd} \
 	     {readelf --dyn-syms pr20828-c.sd}} \
-	    "pr20828-2.so"]]
+	    "pr20828-2.so"] \
+	[list \
+	    "PR ld/20828 dynamic symbols with section GC\
+	     (versioned shared library)" \
+	    "$LFLAGS -shared --gc-sections -T pr20828.ld\
+	     --version-script=pr20828-v.ver" \
+	    "" "$AFLAGS_PIC" \
+	    {pr20828.s} \
+	    {{readelf --dyn-syms pr20828-c.sd} \
+	     {readelf --dyn-syms pr20828-d.sd} \
+	     {readelf --dyn-syms pr20828-e.sd}} \
+	    "libpr20828-v.so"] \
+	[list \
+	    "PR ld/20828 dynamic symbols with section GC (versioned)" \
+	    "$LFLAGS -shared --gc-sections -T pr20828.ld\
+	     --version-script=pr20828-v.ver" \
+	    "tmpdir/libpr20828-v.so" \
+	    "$AFLAGS_PIC" \
+	    {pr20828.s} \
+	    {{readelf --dyn-syms pr20828-c.sd} \
+	     {readelf --dyn-syms pr20828-d.sd} \
+	     {readelf --dyn-syms pr20828-e.sd}} \
+	    "pr20828-v.so"] \
+	[list \
+	    "PR ld/20828 forcibly exported symbol version without section GC" \
+	    "$LFLAGS -e foo -E -T pr20828-v.ld" "" "" \
+	    {pr20828-v.s} \
+	    {{objdump -p pr20828-v.od}} \
+	    "pr20828-v-1"] \
+	[list \
+	    "PR ld/20828 forcibly exported symbol version with section GC" \
+	    "$LFLAGS -e foo --gc-sections -E -T pr20828-v.ld" "" "" \
+	    {pr20828-v.s} \
+	    {{objdump -p pr20828-v.od}} \
+	    "pr20828-v-2"]]
 }
 
 # Check to see if the C compiler works