[PowerPC] Revert r185476 and fix up TLS variant kinds

In the commit message to r185476 I wrote:

>The PowerPC-specific modifiers VK_PPC_TLSGD and VK_PPC_TLSLD
>correspond exactly to the generic modifiers VK_TLSGD and VK_TLSLD.
>This causes some confusion with the asm parser, since VK_PPC_TLSGD
>is output as @tlsgd, which is then read back in as VK_TLSGD.
>
>To avoid this confusion, this patch removes the PowerPC-specific
>modifiers and uses the generic modifiers throughout.  (The only
>drawback is that the generic modifiers are printed in upper case
>while the usual convention on PowerPC is to use lower-case modifiers.
>But this is just a cosmetic issue.)

This was unfortunately incorrect, there is is fact another,
serious drawback to using the default VK_TLSLD/VK_TLSGD
variant kinds: using these causes ELFObjectWriter::RelocNeedsGOT
to return true, which in turn causes the ELFObjectWriter to emit
an undefined reference to _GLOBAL_OFFSET_TABLE_.

This is a problem on powerpc64, because it uses the TOC instead
of the GOT, and the linker does not provide _GLOBAL_OFFSET_TABLE_,
so the symbol remains undefined.  This means shared libraries
using TLS built with the integrated assembler are currently
broken.

While the whole RelocNeedsGOT / _GLOBAL_OFFSET_TABLE_ situation
probably ought to be properly fixed at some point, for now I'm
simply reverting the r185476 commit.  Now this in turn exposes
the breakage of handling @tlsgd/@tlsld in the asm parser that
this check-in was originally intended to fix.

To avoid this regression, I'm also adding a different fix for
this problem: while common code now parses @tlsgd as VK_TLSGD,
a special hack in the asm parser translates this code to the
platform-specific VK_PPC_TLSGD that the back-end now expects.
While this is not really pretty, it's self-contained and
shouldn't hurt anything else for now.  One the underlying
problem is fixed, this hack can be reverted again.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185945 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 4 insertions, 4 deletions

diff --git a/test/MC/PowerPC/ppc64-fixups.s b/test/MC/PowerPC/ppc64-fixups.s
index 7347432..56f99d8 100644
--- a/test/MC/PowerPC/ppc64-fixups.s
+++ b/test/MC/PowerPC/ppc64-fixups.s
@@ -404,15 +404,15 @@ base:
 # CHECK-REL:                             0x{{[0-9A-F]*[26AE]}} R_PPC64_GOT_TLSLD16 target 0x0
          addi 3, 3, target@got@tlsld
 
-# CHECK: bl __tls_get_addr(target@TLSGD) # encoding: [0b010010BB,B,B,0bBBBBBB01]
-# CHECK-NEXT:                            #   fixup A - offset: 0, value: target@TLSGD, kind: fixup_ppc_nofixup
+# CHECK: bl __tls_get_addr(target@tlsgd) # encoding: [0b010010BB,B,B,0bBBBBBB01]
+# CHECK-NEXT:                            #   fixup A - offset: 0, value: target@tlsgd, kind: fixup_ppc_nofixup
 # CHECK-NEXT:                            #   fixup B - offset: 0, value: __tls_get_addr, kind: fixup_ppc_br24
 # CHECK-REL:                             0x{{[0-9A-F]*[048C]}} R_PPC64_TLSGD target 0x0
 # CHECK-REL-NEXT:                        0x{{[0-9A-F]*[048C]}} R_PPC64_REL24 __tls_get_addr 0x0
          bl __tls_get_addr(target@tlsgd)
 
-# CHECK: bl __tls_get_addr(target@TLSLD) # encoding: [0b010010BB,B,B,0bBBBBBB01]
-# CHECK-NEXT:                            #   fixup A - offset: 0, value: target@TLSLD, kind: fixup_ppc_nofixup
+# CHECK: bl __tls_get_addr(target@tlsld) # encoding: [0b010010BB,B,B,0bBBBBBB01]
+# CHECK-NEXT:                            #   fixup A - offset: 0, value: target@tlsld, kind: fixup_ppc_nofixup
 # CHECK-NEXT:                            #   fixup B - offset: 0, value: __tls_get_addr, kind: fixup_ppc_br24
 # CHECK-REL:                             0x{{[0-9A-F]*[048C]}} R_PPC64_TLSLD target 0x0
 # CHECK-REL-NEXT:                        0x{{[0-9A-F]*[048C]}} R_PPC64_REL24 __tls_get_addr 0x0