Pull in r221703 from upstream llvm trunk (by Bill Schmidt):

  [PowerPC] Replace foul hackery with real calls to __tls_get_addr

  My original support for the general dynamic and local dynamic TLS
  models contained some fairly obtuse hacks to generate calls to
  __tls_get_addr when lowering a TargetGlobalAddress.  Rather than
  generating real calls, special GET_TLS_ADDR nodes were used to wrap
  the calls and only reveal them at assembly time.  I attempted to
  provide correct parameter and return values by chaining CopyToReg and
  CopyFromReg nodes onto the GET_TLS_ADDR nodes, but this was also not
  fully correct.  Problems were seen with two back-to-back stores to TLS
  variables, where the call sequences ended up overlapping with unhappy
  results.  Additionally, since these weren't real calls, the proper
  register side effects of a call were not recorded, so clobbered values
  were kept live across the calls.

  The proper thing to do is to lower these into calls in the first
  place.  This is relatively straightforward; see the changes to
  PPCTargetLowering::LowerGlobalTLSAddress() in PPCISelLowering.cpp.
  The changes here are standard call lowering, except that we need to
  track the fact that these calls will require a relocation.  This is
  done by adding a machine operand flag of MO_TLSLD or MO_TLSGD to the
  TargetGlobalAddress operand that appears earlier in the sequence.

  The calls to LowerCallTo() eventually find their way to
  LowerCall_64SVR4() or LowerCall_32SVR4(), which call FinishCall(),
  which calls PrepareCall().  In PrepareCall(), we detect the calls to
  __tls_get_addr and immediately snag the TargetGlobalTLSAddress with
  the annotated relocation information.  This becomes an extra operand
  on the call following the callee, which is expected for nodes of type
  tlscall.  We change the call opcode to CALL_TLS for this case.  Back
  in FinishCall(), we change it again to CALL_NOP_TLS for 64-bit only,
  since we require a TOC-restore nop following the call for the 64-bit
  ABIs.

  During selection, patterns in PPCInstrInfo.td and PPCInstr64Bit.td
  convert the CALL_TLS nodes into BL_TLS nodes, and convert the
  CALL_NOP_TLS nodes into BL8_NOP_TLS nodes.  This replaces the code
  removed from PPCAsmPrinter.cpp, as the BL_TLS or BL8_NOP_TLS
  nodes can now be emitted normally using their patterns and the
  associated printTLSCall print method.

  Finally, as a result of these changes, all references to get-tls-addr
  in its various guises are no longer used, so they have been removed.

  There are existing TLS tests to verify the changes haven't messed
  anything up).  I've added one new test that verifies that the problem
  with the original code has been fixed.

This fixes a fatal "Bad machine code" error when compiling parts of
libgomp for 32-bit PowerPC.

0 files changed, 0 insertions, 0 deletions