[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

2 files changed, 50 insertions, 0 deletions

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 00000000000..f0691980989
--- /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
+}
diff --git a/llvm/test/CodeGen/X86/stack-probes.ll b/llvm/test/CodeGen/X86/stack-probes.ll
new file mode 100644
index 00000000000..861a975f6cb
--- /dev/null
+++ b/llvm/test/CodeGen/X86/stack-probes.ll
@@ -0,0 +1,29 @@
+; RUN: llc -mtriple=i386-pc-linux-gnu < %s -o - | FileCheck --check-prefix=X86-LINUX %s
+; RUN: llc -mtriple=x86_64-pc-linux-gnu < %s -o - | FileCheck --check-prefix=X64-LINUX %s
+; RUN: llc -mtriple=x86_64-pc-linux-gnu -code-model=large < %s -o - | FileCheck --check-prefix=X64-LINUX-LARGE %s
+
+declare void @use([40096 x i8]*)
+
+; Ensure calls to __probestack occur for large stack frames
+define void @test() "probe-stack"="__probestack" {
+  %array = alloca [40096 x i8], align 16
+  call void @use([40096 x i8]* %array)
+  ret void
+
+; X86-LINUX-LABEL:       test:
+; X86-LINUX:             movl $40124, %eax # imm = 0x9CBC
+; X86-LINUX-NEXT:        calll __probestack
+; X86-LINUX-NEXT:        subl %eax, %esp
+
+; X64-LINUX-LABEL:       test:
+; X64-LINUX:             movl $40104, %eax # imm = 0x9CA8
+; X64-LINUX-NEXT:        callq __probestack
+; X64-LINUX-NEXT:        subq %rax, %rsp
+
+; X64-LINUX-LARGE-LABEL: test:
+; X64-LINUX-LARGE:       movl $40104, %eax # imm = 0x9CA8
+; X64-LINUX-LARGE-NEXT:  movabsq $__probestack, %r11
+; X64-LINUX-LARGE-NEXT:  callq *%r11
+; X64-LINUX-LARGE-NEXT:  subq %rax, %rsp
+
+}