From f85cd8bc137c6afcfbee95a1ec74379cbe027862 Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Wed, 26 May 2010 22:21:25 +0000
Subject: Reinstate checking of stackrestore, with checking for both Read and
 Write, and add a comment explaining this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104756 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Analysis/Lint.cpp | 8 ++++++++
 test/Other/lint.ll    | 3 +++
 2 files changed, 11 insertions(+)

diff --git a/lib/Analysis/Lint.cpp b/lib/Analysis/Lint.cpp
index a19e13e..1fae14f 100644
--- a/lib/Analysis/Lint.cpp
+++ b/lib/Analysis/Lint.cpp
@@ -285,6 +285,14 @@ void Lint::visitCallSite(CallSite CS) {
       visitMemoryReference(I, CS.getArgument(0), 0, 0,
                            MemRef::Read | MemRef::Write);
       break;
+
+    case Intrinsic::stackrestore:
+      // Stackrestore doesn't read or write memory, but it sets the
+      // stack pointer, which the compiler may read from or write to
+      // at any time, so check it for both readability and writeability.
+      visitMemoryReference(I, CS.getArgument(0), 0, 0,
+                           MemRef::Read | MemRef::Write);
+      break;
     }
 }
 
diff --git a/test/Other/lint.ll b/test/Other/lint.ll
index eb0b762..1f9efe3 100644
--- a/test/Other/lint.ll
+++ b/test/Other/lint.ll
@@ -2,6 +2,7 @@
 target datalayout = "e-p:64:64:64"
 
 declare fastcc void @bar()
+declare void @llvm.stackrestore(i8*)
 
 @CG = constant i32 7
 
@@ -50,6 +51,8 @@ define i32 @foo() noreturn {
   %lb = load i32* bitcast (i8* blockaddress(@foo, %next) to i32*)
 ; CHECK: Call to block address
   call void()* bitcast (i8* blockaddress(@foo, %next) to void()*)()
+; CHECK: Undefined behavior: Null pointer dereference
+  call void @llvm.stackrestore(i8* null)
 
   br label %next
 
-- 
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