From 5acc58fcfb403d1638856133088727c4e1a22fce Mon Sep 17 00:00:00 2001
From: Akira Hatanaka <ahatanaka@apple.com>
Date: Thu, 7 Aug 2014 23:08:24 +0000
Subject: [stack protector] Look through bitcasts to get global variable
 __stack_chk_guard.

Handle the case where the pointer operand of the load instruction that loads the
stack guard is not a global variable but instead a bitcast.

%StackGuard = load i8** bitcast (i64** @__stack_chk_guard to i8**)
call void @llvm.stackprotector(i8* %StackGuard, i8** %StackGuardSlot)

Original test case provided by Ana Pazos.

This fixes PR20558.

llvm-svn: 215167
---
 .../CodeGen/AArch64/stack-guard-remat-bitcast.ll   | 26 ++++++++++++++++++++++
 1 file changed, 26 insertions(+)
 create mode 100644 llvm/test/CodeGen/AArch64/stack-guard-remat-bitcast.ll

(limited to 'llvm/test/CodeGen/AArch64/stack-guard-remat-bitcast.ll')

diff --git a/llvm/test/CodeGen/AArch64/stack-guard-remat-bitcast.ll b/llvm/test/CodeGen/AArch64/stack-guard-remat-bitcast.ll
new file mode 100644
index 00000000000..bedbf5facbb
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/stack-guard-remat-bitcast.ll
@@ -0,0 +1,26 @@
+; RUN: llc < %s -mtriple=arm64-apple-ios -relocation-model=pic | FileCheck %s
+
+@__stack_chk_guard = external global i64*
+
+; PR20558
+
+; CHECK: adrp [[R0:x[0-9]+]], ___stack_chk_guard@GOTPAGE
+; CHECK: ldr  [[R1:x[0-9]+]], {{\[}}[[R0]], ___stack_chk_guard@GOTPAGEOFF{{\]}}
+; CHECK: ldr  [[R2:x[0-9]+]], {{\[}}[[R1]]{{\]}}
+; CHECK: stur [[R2]], {{\[}}x29, [[SLOT0:[0-9#\-]+]]{{\]}}
+; CHECK: ldur [[R3:x[0-9]+]], {{\[}}x29, [[SLOT0]]{{\]}}
+; CHECK: sub  [[R4:x[0-9]+]], [[R2]], [[R3]]
+; CHECK: cbnz [[R4]], LBB
+
+define i32 @test_stack_guard_remat2() {
+entry:
+  %StackGuardSlot = alloca i8*
+  %StackGuard = load i8** bitcast (i64** @__stack_chk_guard to i8**)
+  call void @llvm.stackprotector(i8* %StackGuard, i8** %StackGuardSlot)
+  %container = alloca [32 x i8], align 1
+  call void @llvm.stackprotectorcheck(i8** bitcast (i64** @__stack_chk_guard to i8**))
+  ret i32 -1
+}
+
+declare void @llvm.stackprotector(i8*, i8**)
+declare void @llvm.stackprotectorcheck(i8**)
-- 
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