Add a "probe-stack" attribute

This attribute is used to ensure the guard page is triggered on stack
overflow. Stack frames larger than the guard page size will generate
a call to __probestack to touch each page so the guard page won't
be skipped.

Reviewed By: majnemer

Differential Revision: https://reviews.llvm.org/D34386

llvm-svn: 305939

1 files changed, 20 insertions, 0 deletions

diff --git a/llvm/test/Transforms/Inline/inline-probe-stack.ll b/llvm/test/Transforms/Inline/inline-probe-stack.ll
new file mode 100644
index 00000000000..bddee16d30b
--- /dev/null
+++ b/llvm/test/Transforms/Inline/inline-probe-stack.ll
@@ -0,0 +1,20 @@
+; RUN: opt %s -inline -S | FileCheck %s
+
+define internal void @inner() "probe-stack"="__probestackinner" {
+  ret void
+}
+
+define void @outerNoAttribute() {
+  call void @inner()
+  ret void
+}
+
+define void @outerConflictingAttribute() "probe-stack"="__probestackouter" {
+  call void @inner()
+  ret void
+}
+
+; CHECK: define void @outerNoAttribute() #0
+; CHECK: define void @outerConflictingAttribute() #1
+; CHECK: attributes #0 = { "probe-stack"="__probestackinner" }
+; CHECK: attributes #1 = { "probe-stack"="__probestackouter" }