[SystemZ] Support stackmaps and patchpoints

This adds back-end support for the @llvm.experimental.stackmap and
@llvm.experimental.patchpoint intrinsics.

llvm-svn: 326611

1 files changed, 27 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/SystemZ/stackmap-shadow-optimization.ll b/llvm/test/CodeGen/SystemZ/stackmap-shadow-optimization.ll
new file mode 100644
index 00000000000..5b828e73eb9
--- /dev/null
+++ b/llvm/test/CodeGen/SystemZ/stackmap-shadow-optimization.ll
@@ -0,0 +1,27 @@
+; RUN: llc < %s -mtriple=s390x-linux-gnu | FileCheck %s
+
+; Check that the stackmap shadow optimization is only outputting a 2-byte
+; nop here. 8-bytes are requested, but 6 are covered by the code for the call to
+; bar.  However, the frame teardown and the return do not count towards the
+; stackmap shadow as the call return counts as a branch target so must flush
+; the shadow.
+; Note that in order for a thread to not return in to the patched space
+; the call must be at the end of the shadow, so the required nop must be
+; before the call, not after.
+define void @shadow_optimization_test() {
+entry:
+; CHECK-LABEL:  shadow_optimization_test:
+; CHECK:        brasl %r14, bar@PLT
+; CHECK-NEXT:   .Ltmp
+; CHECK-NEXT:   bcr 0, %r0
+; CHECK-NEXT:   brasl %r14, bar@PLT
+; CHECK-NEXT:   brasl %r14, bar@PLT
+  call void @bar()
+  tail call void (i64, i32, ...) @llvm.experimental.stackmap(i64 0, i32 8)
+  call void @bar()
+  call void @bar()
+  ret void
+}
+declare void @bar()
+
+declare void @llvm.experimental.stackmap(i64, i32, ...)