[X86] Add support for "probe-stack" attribute
This commit adds prologue code emission for stack probe function
calls.
Reviewed By: majnemer
Differential Revision: https://reviews.llvm.org/D34387
llvm-svn: 306010
diff --git a/llvm/test/CodeGen/X86/stack-probe-red-zone.ll b/llvm/test/CodeGen/X86/stack-probe-red-zone.ll
new file mode 100644
index 0000000..f069198
--- /dev/null
+++ b/llvm/test/CodeGen/X86/stack-probe-red-zone.ll
@@ -0,0 +1,21 @@
+; RUN: llc -mtriple=x86_64-pc-linux-gnu < %s -o - | FileCheck %s
+
+; Ensure that red zone usage occurs.
+define void @testStackProbesOff() {
+ %array = alloca [40096 x i8], align 16
+ ret void
+
+; CHECK-LABEL: testStackProbesOff:
+; CHECK: subq $39976, %rsp # imm = 0x9C28
+}
+
+; Ensure stack probes do not result in red zone usage.
+define void @testStackProbesOn() "probe-stack"="__probestack" {
+ %array = alloca [40096 x i8], align 16
+ ret void
+
+; CHECK-LABEL: testStackProbesOn:
+; CHECK: movl $40104, %eax # imm = 0x9CA8
+; CHECK-NEXT: callq __probestack
+; CHECK-NEXT: subq %rax, %rsp
+}