[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
diff --git a/llvm/test/CodeGen/SystemZ/tls-02.ll b/llvm/test/CodeGen/SystemZ/tls-02.ll
new file mode 100644
index 0000000..15918d0
--- /dev/null
+++ b/llvm/test/CodeGen/SystemZ/tls-02.ll
@@ -0,0 +1,18 @@
+; Test initial-exec TLS accesses.
+;
+; RUN: llc < %s -mcpu=z10 -mtriple=s390x-linux-gnu -relocation-model=pic | FileCheck %s -check-prefix=CHECK-MAIN
+
+@x = thread_local(initialexec) global i32 0
+
+; The offset must be loaded from the GOT. This TLS access model does
+; not use literal pool constants.
+define i32 *@foo() {
+; CHECK-MAIN-LABEL: foo:
+; CHECK-MAIN: ear [[HIGH:%r[0-5]]], %a0
+; CHECK-MAIN: sllg %r2, [[HIGH]], 32
+; CHECK-MAIN: ear %r2, %a1
+; CHECK-MAIN: larl %r1, x@INDNTPOFF
+; CHECK-MAIN: ag %r2, 0(%r1)
+; CHECK-MAIN: br %r14
+ ret i32 *@x
+}