This patch improves the 64-bit PowerPC InitialExec TLS support by providing

for a wider range of GOT entries that can hold thread-relative offsets.
This matches the behavior of GCC, which was not documented in the PPC64 TLS
ABI.  The ABI will be updated with the new code sequence.

Former sequence:

  ld 9,x@got@tprel(2)
  add 9,9,x@tls

New sequence:

  addis 9,2,x@got@tprel@ha
  ld 9,x@got@tprel@l(9)
  add 9,9,x@tls

Note that a linker optimization exists to transform the new sequence into
the shorter sequence when appropriate, by replacing the addis with a nop
and modifying the base register and relocation type of the ld.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170209 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bill Schmidt
2012-12-14 17:02:38 +00:00
parent 79c3742620
commit b453e16855
13 changed files with 67 additions and 48 deletions
+6 -3
View File
@@ -578,7 +578,8 @@ const char *PPCTargetLowering::getTargetNodeName(unsigned Opcode) const {
case PPCISD::ADDIS_TOC_HA: return "PPCISD::ADDIS_TOC_HA";
case PPCISD::LD_TOC_L: return "PPCISD::LD_TOC_L";
case PPCISD::ADDI_TOC_L: return "PPCISD::ADDI_TOC_L";
case PPCISD::LD_GOT_TPREL: return "PPCISD::LD_GOT_TPREL";
case PPCISD::ADDIS_GOT_TPREL_HA: return "PPCISD::ADDIS_GOT_TPREL_HA";
case PPCISD::LD_GOT_TPREL_L: return "PPCISD::LD_GOT_TPREL_L";
case PPCISD::ADD_TLS: return "PPCISD::ADD_TLS";
case PPCISD::ADDIS_TLSGD_HA: return "PPCISD::ADDIS_TLSGD_HA";
case PPCISD::ADDI_TLSGD_L: return "PPCISD::ADDI_TLSGD_L";
@@ -1353,8 +1354,10 @@ SDValue PPCTargetLowering::LowerGlobalTLSAddress(SDValue Op,
if (Model == TLSModel::InitialExec) {
SDValue TGA = DAG.getTargetGlobalAddress(GV, dl, PtrVT, 0, 0);
SDValue GOTReg = DAG.getRegister(PPC::X2, MVT::i64);
SDValue TPOffset = DAG.getNode(PPCISD::LD_GOT_TPREL, dl,
PtrVT, TGA, GOTReg);
SDValue TPOffsetHi = DAG.getNode(PPCISD::ADDIS_GOT_TPREL_HA, dl,
PtrVT, GOTReg, TGA);
SDValue TPOffset = DAG.getNode(PPCISD::LD_GOT_TPREL_L, dl,
PtrVT, TGA, TPOffsetHi);
return DAG.getNode(PPCISD::ADD_TLS, dl, PtrVT, TPOffset, TGA);
}