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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169281 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 17 insertions, 0 deletions

diff --git a/lib/Target/PowerPC/PPCAsmPrinter.cpp b/lib/Target/PowerPC/PPCAsmPrinter.cpp
index b33b04e260..4315bc1a07 100644
--- a/lib/Target/PowerPC/PPCAsmPrinter.cpp
+++ b/lib/Target/PowerPC/PPCAsmPrinter.cpp
@@ -513,6 +513,23 @@ void PPCAsmPrinter::EmitInstruction(const MachineInstr *MI) {
     OutStreamer.EmitInstruction(TmpInst);
     return;
   }
+  case PPC::LDgotTPREL: {
+    // Transform %Xd = LDgotTPREL <ga:@sym>, %Xs
+    LowerPPCMachineInstrToMCInst(MI, TmpInst, *this, Subtarget.isDarwin());
+
+    // Change the opcode to LDrs, which is a form of LD with the offset
+    // specified by a SymbolLo.
+    TmpInst.setOpcode(PPC::LDrs);
+    const MachineOperand &MO = MI->getOperand(1);
+    const GlobalValue *GValue = MO.getGlobal();
+    MCSymbol *MOSymbol = Mang->getSymbol(GValue);
+    const MCExpr *Exp =
+      MCSymbolRefExpr::Create(MOSymbol, MCSymbolRefExpr::VK_PPC_GOT_TPREL16_DS,
+                              OutContext);
+    TmpInst.getOperand(1) = MCOperand::CreateExpr(Exp);
+    OutStreamer.EmitInstruction(TmpInst);
+    return;
+  }
   case PPC::MFCRpseud:
   case PPC::MFCR8pseud:
     // Transform: %R3 = MFCRpseud %CR7