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, 16 insertions, 0 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCCodeEmitter.cpp b/llvm/lib/Target/PowerPC/PPCCodeEmitter.cpp
index 7b37dff2c90..0dcb5deb5d4 100644
--- a/llvm/lib/Target/PowerPC/PPCCodeEmitter.cpp
+++ b/llvm/lib/Target/PowerPC/PPCCodeEmitter.cpp
@@ -68,6 +68,8 @@ namespace {
     unsigned getLO16Encoding(const MachineInstr &MI, unsigned OpNo) const;
     unsigned getMemRIEncoding(const MachineInstr &MI, unsigned OpNo) const;
     unsigned getMemRIXEncoding(const MachineInstr &MI, unsigned OpNo) const;
+    unsigned getTLSOffsetEncoding(const MachineInstr &MI, unsigned OpNo) const;
+    unsigned getTLSRegEncoding(const MachineInstr &MI, unsigned OpNo) const;
 
     const char *getPassName() const { return "PowerPC Machine Code Emitter"; }
 
@@ -243,6 +245,20 @@ unsigned PPCCodeEmitter::getMemRIXEncoding(const MachineInstr &MI,
 }
 
 
+unsigned PPCCodeEmitter::getTLSOffsetEncoding(const MachineInstr &MI,
+                                           unsigned OpNo) const {
+  llvm_unreachable("TLS not supported on the old JIT.");
+  return 0;
+}
+
+
+unsigned PPCCodeEmitter::getTLSRegEncoding(const MachineInstr &MI,
+                                           unsigned OpNo) const {
+  llvm_unreachable("TLS not supported on the old JIT.");
+  return 0;
+}
+
+
 unsigned PPCCodeEmitter::getMachineOpValue(const MachineInstr &MI,
                                            const MachineOperand &MO) const {