This patch introduces initial-exec model support for thread-local storage

on 64-bit PowerPC ELF.

The patch includes code to handle external assembly and MC output with the
integrated assembler.  It intentionally does not support the "old" JIT.

For the initial-exec TLS model, the ABI requires the following to calculate
the address of external thread-local variable x:

 Code sequence            Relocation                  Symbol
  ld 9,x@got@tprel(2)      R_PPC64_GOT_TPREL16_DS      x
  add 9,9,x@tls            R_PPC64_TLS                 x

The register 9 is arbitrary here.  The linker will replace x@got@tprel
with the offset relative to the thread pointer to the generated GOT
entry for symbol x.  It will replace x@tls with the thread-pointer
register (13).

The two test cases verify correct assembly output and relocation output
as just described.

PowerPC-specific selection node variants are added for the two
instructions above:  LD_GOT_TPREL and ADD_TLS.  These are inserted
when an initial-exec global variable is encountered by
PPCTargetLowering::LowerGlobalTLSAddress(), and later lowered to
machine instructions LDgotTPREL and ADD8TLS.  LDgotTPREL is a pseudo
that uses the same LDrs support added for medium code model's LDtocL,
with a different relocation type.

The rest of the processing is straightforward.

llvm-svn: 169281

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCMCInstLower.cpp b/llvm/lib/Target/PowerPC/PPCMCInstLower.cpp
index 73f7a2cfd57..1c4af901f72 100644
--- a/llvm/lib/Target/PowerPC/PPCMCInstLower.cpp
+++ b/llvm/lib/Target/PowerPC/PPCMCInstLower.cpp
@@ -114,6 +114,12 @@ static MCOperand GetSymbolRef(const MachineOperand &MO, const MCSymbol *Symbol,
                                break;
     case PPCII::MO_TPREL16_LO: RefKind = MCSymbolRefExpr::VK_PPC_TPREL16_LO;
                                break;
+    case PPCII::MO_GOT_TPREL16_DS:
+      RefKind = MCSymbolRefExpr::VK_PPC_GOT_TPREL16_DS;
+      break;
+    case PPCII::MO_TLS:
+      RefKind = MCSymbolRefExpr::VK_PPC_TLS;
+      break;
    }
 
   // FIXME: This isn't right, but we don't have a good way to express this in