llvm/lib
Ulrich Weigand 7a34599db0 [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
2013-07-09 16:41:09 +00:00
..
Analysis Fix a SCEV update problem. 2013-07-08 17:33:13 +00:00
AsmParser Extend 'readonly' and 'readnone' to work on function arguments as well as 2013-07-06 00:29:58 +00:00
Bitcode Remove the Copied parameter from MemoryObject::readBytes. 2013-05-24 10:54:58 +00:00
CodeGen Revert r185872 - "Stop emitting weak symbols into the "coal" sections" 2013-07-09 10:00:16 +00:00
DebugInfo Spell correct (s/begining/beginning/) 2013-06-19 21:42:05 +00:00
ExecutionEngine Use SmallVectorImpl::iterator/const_iterator instead of SmallVector to avoid specifying the vector size. 2013-07-04 01:31:24 +00:00
IR Revert "DebugInfo: remove unused helper function getDICompositeType." 2013-07-09 00:16:56 +00:00
IRReader keep only the StringRef version of getFileOrSTDIN. 2013-06-25 05:28:34 +00:00
Linker Extend RemapInstruction and friends to take an optional new parameter, a ValueMaterializer. 2013-05-28 15:17:05 +00:00
MC [PowerPC] Revert r185476 and fix up TLS variant kinds 2013-07-09 16:41:09 +00:00
Object Add missing getters. They will be used in llvm-ar. 2013-07-09 12:49:24 +00:00
Option Fix a crash bug in dumping options with groups 2013-06-26 22:43:37 +00:00
Support Revert r185852. 2013-07-08 20:27:34 +00:00
TableGen keep only the StringRef version of getFileOrSTDIN. 2013-06-25 05:28:34 +00:00
Target [PowerPC] Revert r185476 and fix up TLS variant kinds 2013-07-09 16:41:09 +00:00
Transforms InstCombine: Fix typo in comment for visitICmpInstWithInstAndIntCst 2013-07-09 09:24:35 +00:00
CMakeLists.txt Move lib/Archive to tools/llvm-ar. 2013-06-17 15:47:20 +00:00
LLVMBuild.txt Move lib/Archive to tools/llvm-ar. 2013-06-17 15:47:20 +00:00
Makefile Move lib/Archive to tools/llvm-ar. 2013-06-17 15:47:20 +00:00