[SystemZ] Support all TLS access models - CodeGen part

The current SystemZ back-end only supports the local-exec TLS access model.
This patch adds all required CodeGen support for the other TLS models, which
means in particular:

- Expand initial-exec TLS accesses by loading TLS offsets from the GOT
  using @indntpoff relocations.

- Expand general-dynamic and local-dynamic accesses by generating the
  appropriate calls to __tls_get_offset.  Note that this routine has
  a non-standard ABI and requires loading the GOT pointer into %r12,
  so the patch also adds support for the GLOBAL_OFFSET_TABLE ISD node.

- Add a new platform-specific optimization pass to remove redundant
  __tls_get_offset calls in the local-dynamic model (modeled after
  the corresponding X86 pass).

- Add test cases verifying all access models and optimizations.

llvm-svn: 229654

1 files changed, 7 insertions, 0 deletions

diff --git a/llvm/lib/Target/SystemZ/SystemZOperators.td b/llvm/lib/Target/SystemZ/SystemZOperators.td
index c70e662db42..51ac5daad54 100644
--- a/llvm/lib/Target/SystemZ/SystemZOperators.td
+++ b/llvm/lib/Target/SystemZ/SystemZOperators.td
@@ -90,6 +90,7 @@ def callseq_start       : SDNode<"ISD::CALLSEQ_START", SDT_CallSeqStart,
 def callseq_end         : SDNode<"ISD::CALLSEQ_END",   SDT_CallSeqEnd,
                                  [SDNPHasChain, SDNPSideEffect, SDNPOptInGlue,
                                   SDNPOutGlue]>;
+def global_offset_table : SDNode<"ISD::GLOBAL_OFFSET_TABLE", SDTPtrLeaf>;
 
 // Nodes for SystemZISD::*.  See SystemZISelLowering.h for more details.
 def z_retflag           : SDNode<"SystemZISD::RET_FLAG", SDTNone,
@@ -100,6 +101,12 @@ def z_call              : SDNode<"SystemZISD::CALL", SDT_ZCall,
 def z_sibcall           : SDNode<"SystemZISD::SIBCALL", SDT_ZCall,
                                  [SDNPHasChain, SDNPOutGlue, SDNPOptInGlue,
                                   SDNPVariadic]>;
+def z_tls_gdcall        : SDNode<"SystemZISD::TLS_GDCALL", SDT_ZCall,
+                                 [SDNPHasChain, SDNPInGlue, SDNPOutGlue,
+                                  SDNPVariadic]>;
+def z_tls_ldcall        : SDNode<"SystemZISD::TLS_LDCALL", SDT_ZCall,
+                                 [SDNPHasChain, SDNPInGlue, SDNPOutGlue,
+                                  SDNPVariadic]>;
 def z_pcrel_wrapper     : SDNode<"SystemZISD::PCREL_WRAPPER", SDT_ZWrapPtr, []>;
 def z_pcrel_offset      : SDNode<"SystemZISD::PCREL_OFFSET",
                                  SDT_ZWrapOffset, []>;