From 8d807025374d8a1eac8fc148fe746aff4075ead2 Mon Sep 17 00:00:00 2001
From: Quentin Colombet <qcolombet@apple.com>
Date: Sat, 14 Nov 2015 01:55:17 +0000
Subject: [PATCH] [ShrinkWrapping] Disable the optimization for functions with
 sanitize like attribute.

Even if the target supports shrink-wrapping, the prologue and epilogue
must not move because a crash can happen anywhere and sanitizers need
to be able to unwind from the PC of the crash.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253116 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/ShrinkWrap.cpp                    |  9 ++++-
 .../X86/x86-sanitizer-shrink-wrapping.ll      | 40 +++++++++++++++++++
 2 files changed, 48 insertions(+), 1 deletion(-)
 create mode 100644 test/CodeGen/X86/x86-sanitizer-shrink-wrapping.ll

diff --git a/lib/CodeGen/ShrinkWrap.cpp b/lib/CodeGen/ShrinkWrap.cpp
index 8a797018815..07371f66061 100644
--- a/lib/CodeGen/ShrinkWrap.cpp
+++ b/lib/CodeGen/ShrinkWrap.cpp
@@ -468,7 +468,14 @@ bool ShrinkWrap::isShrinkWrapEnabled(const MachineFunction &MF) {
     return TFI->enableShrinkWrapping(MF) &&
       // Windows with CFI has some limitations that make it impossible
       // to use shrink-wrapping.
-      !MF.getTarget().getMCAsmInfo()->usesWindowsCFI();
+      !MF.getTarget().getMCAsmInfo()->usesWindowsCFI() &&
+      // Sanitizers look at the value of the stack at the location
+      // of the crash. Since a crash can happen anywhere, the
+      // frame must be lowered before anything else happen for the
+      // sanitizers to be able to get a correct stack frame.
+      !(MF.getFunction()->hasFnAttribute(Attribute::SanitizeAddress) ||
+        MF.getFunction()->hasFnAttribute(Attribute::SanitizeThread) ||
+        MF.getFunction()->hasFnAttribute(Attribute::SanitizeMemory));
   // If EnableShrinkWrap is set, it takes precedence on whatever the
   // target sets. The rational is that we assume we want to test
   // something related to shrink-wrapping.
diff --git a/test/CodeGen/X86/x86-sanitizer-shrink-wrapping.ll b/test/CodeGen/X86/x86-sanitizer-shrink-wrapping.ll
new file mode 100644
index 00000000000..4cb11bf3f5c
--- /dev/null
+++ b/test/CodeGen/X86/x86-sanitizer-shrink-wrapping.ll
@@ -0,0 +1,40 @@
+; RUN: llc -o - < %s | FileCheck %s
+
+target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
+target triple = "x86_64-apple-macosx"
+
+; Even if the target supports shrink-wrapping, the prologue and epilogue
+; must not move because a crash can happen anywhere and sanitizers need
+; to be able to unwind from the PC of the crash.
+; CHECK-LABEL: sanitize:
+; CHECK: pushq
+; CHECK: incl 40
+; CHECK: popq
+; CHECK-NEXT: retq
+; CHECK: movl $40, %edi
+; CHECK-NEXT callq ___asan_report_load4
+define  void @sanitize() #0 {
+entry:
+  %tmp = load i8, i8* inttoptr (i64 17592186044421 to i8*)
+  %tmp1 = icmp ne i8 %tmp, 0
+  br i1 %tmp1, label %if.then, label %else
+
+if.then:
+  %tmp3 = icmp sge i8 3, %tmp
+  br i1 %tmp3, label %else, label %end
+
+else:
+  call void @__asan_report_load4(i64 40)
+  call void asm sideeffect "", ""()
+  unreachable
+
+end:
+  %tmp6 = load i32, i32* inttoptr (i64 40 to i32*), align 8
+  %inc = add nsw i32 %tmp6, 1
+  store i32 %inc, i32* inttoptr (i64 40 to i32*), align 8
+  ret void
+}
+
+attributes #0 = { sanitize_address nounwind "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" }
+
+declare void @__asan_report_load4(i64)
-- 
2.34.1