gold: x86-64: Fix TLSDESC relaxation for x32

X32 TLSDESC sequences can be:

40 8d 05 00 00 00 00	rex lea	foo@TLSDESC(%rip), %reg
...
67 ff 10		call	*foo@TLSCALL(%eax)

or the same sequence as LP64:

48 8d 05 00 00 00 00	lea	foo@TLSDESC(%rip), %reg
...
ff 10			call	*foo@TLSCALL(%rax)

We need to support both sequences for x32.  For both GDesc -> IE/LE
transitions,

67 ff 10		call	*foo@TLSCALL(%eax)

should relaxed to

0f 1f 00		nopl	(%rax)

For GDesc -> LE transition,

40 8d 05 00 00 00 00	rex lea	foo@TLSDESC(%rip), %reg

should relaxed to

40 c7 c0 fc ff ff ff	rex movl $foo@tpoff, %reg

For GDesc -> IE transition,

40 8d 05 00 00 00 00	rex lea	foo@TLSDESC(%rip), %reg

should relaxed to

40 8b 05 00 00 00 00	rex movl foo@gottpoff(%rip), %eax

	PR gold/25426
	* x86_64.cc (Target_x86_64<size>::Relocate::tls_desc_gd_to_ie):
	For x32, relax "rex leal foo@tlsdesc(%rip), %reg" to
	"rex movl foo@gottpoff(%rip), %eax" and relax ""call *(%eax)"
	to "nopl (%rax)".
	(Target_x86_64<size>::Relocate::tls_desc_gd_to_le): For x32,
	relax "rex leal foo@tlsdesc(%rip), %reg" to
	"rex movl foo@tpoff, %eax" and relax "call *foo@tlscall(%eax)"
	to "nopl (%rax)".
	* testsuite/Makefile.am (tls_test_gnu2.o): Depend on
	gcctestdir/as.
	(tls_test_file2_gnu2.o): Likewise.
	(tls_test_c_gnu2.o): Likewise.
	* testsuite/Makefile.in: Regenerated.

1 files changed, 59 insertions, 17 deletions

diff --git a/gold/x86_64.cc b/gold/x86_64.cc
index d4f1d6b..1d9d920 100644
--- a/gold/x86_64.cc
+++ b/gold/x86_64.cc
@@ -5472,12 +5472,15 @@ Target_x86_64<size>::Relocate::tls_desc_gd_to_ie(
 {
   if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
     {
-      // leaq foo@tlsdesc(%rip), %rax
-      // ==> movq foo@gottpoff(%rip), %rax
+      // LP64: leaq foo@tlsdesc(%rip), %rax
+      //       ==> movq foo@gottpoff(%rip), %rax
+      // X32:  rex leal foo@tlsdesc(%rip), %eax
+      //       ==> rex movl foo@gottpoff(%rip), %eax
       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
-		     ((view[-3] & 0xfb) == 0x48
+		     (((view[-3] & 0xfb) == 0x48
+		       || (size == 32 && (view[-3] & 0xfb) == 0x40))
 		      && view[-2] == 0x8d
 		      && (view[-1] & 0xc7) == 0x05));
       view[-2] = 0x8b;
@@ -5486,14 +5489,32 @@ Target_x86_64<size>::Relocate::tls_desc_gd_to_ie(
     }
   else
     {
-      // call *foo@tlscall(%rax)
-      // ==> nop; nop
+      // LP64: call *foo@tlscall(%rax)
+      //       ==> xchg %ax, %ax
+      // X32:  call *foo@tlscall(%eax)
+      //       ==> nopl (%rax)
       gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
+      int prefix = 0;
+      if (size == 32 && view[0] == 0x67)
+	{
+	  tls::check_range(relinfo, relnum, rela.get_r_offset(),
+			   view_size, 3);
+	  prefix = 1;
+	}
       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
-		     view[0] == 0xff && view[1] == 0x10);
-      view[0] = 0x66;
-      view[1] = 0x90;
+		     view[prefix] == 0xff && view[prefix + 1] == 0x10);
+      if (prefix)
+	{
+	  view[0] = 0x0f;
+	  view[1] = 0x1f;
+	  view[2] = 0x00;
+	}
+      else
+	{
+	  view[0] = 0x66;
+	  view[1] = 0x90;
+	}
     }
 }
 
@@ -5513,15 +5534,18 @@ Target_x86_64<size>::Relocate::tls_desc_gd_to_le(
 {
   if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
     {
-      // leaq foo@tlsdesc(%rip), %rax
-      // ==> movq foo@tpoff, %rax
+      // LP64: leaq foo@tlsdesc(%rip), %rax
+      //       ==> movq foo@tpoff, %rax
+      // X32:  rex leal foo@tlsdesc(%rip), %eax
+      //       ==> rex movl foo@tpoff, %eax
       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
-		     ((view[-3] & 0xfb) == 0x48
+		     (((view[-3] & 0xfb) == 0x48
+		       || (size == 32 && (view[-3] & 0xfb) == 0x40))
 		      && view[-2] == 0x8d
 		      && (view[-1] & 0xc7) == 0x05));
-      view[-3] = 0x48 | ((view[-3] >> 2) & 1);
+      view[-3] = (view[-3] & 0x48) | ((view[-3] >> 2) & 1);
       view[-2] = 0xc7;
       view[-1] = 0xc0 | ((view[-1] >> 3) & 7);
       value -= tls_segment->memsz();
@@ -5529,14 +5553,32 @@ Target_x86_64<size>::Relocate::tls_desc_gd_to_le(
     }
   else
     {
-      // call *foo@tlscall(%rax)
-      // ==> nop; nop
+      // LP64: call *foo@tlscall(%rax)
+      //       ==> xchg %ax, %ax
+      // X32:  call *foo@tlscall(%eax)
+      //       ==> nopl (%rax)
       gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
+      int prefix = 0;
+      if (size == 32 && view[0] == 0x67)
+	{
+	  tls::check_range(relinfo, relnum, rela.get_r_offset(),
+			   view_size, 3);
+	  prefix = 1;
+	}
       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
-		     view[0] == 0xff && view[1] == 0x10);
-      view[0] = 0x66;
-      view[1] = 0x90;
+		     view[prefix] == 0xff && view[prefix + 1] == 0x10);
+      if (prefix)
+	{
+	  view[0] = 0x0f;
+	  view[1] = 0x1f;
+	  view[2] = 0x00;
+	}
+      else
+	{
+	  view[0] = 0x66;
+	  view[1] = 0x90;
+	}
     }
 }