From d83716804c8417ecbe949992352d10f5876abc4a Mon Sep 17 00:00:00 2001
From: Arnold Schwaighofer <aschwaighofer@apple.com>
Date: Wed, 15 Feb 2017 18:57:06 +0000
Subject: [PATCH] ThreadSanitizer: don't track swifterror memory addresses

They are register promoted by ISel and so it makes no sense to treat them as
memory.

Inserting calls to the thread sanitizer would also generate invalid IR.

You would hit:

"swifterror value can only be loaded and stored from, or as a swifterror
argument!"

llvm-svn: 295215
---
 .../Instrumentation/ThreadSanitizer.cpp       |  7 ++++++
 .../ThreadSanitizer/tsan_basic.ll             | 24 +++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/lib/Transforms/Instrumentation/ThreadSanitizer.cpp b/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
index d9659694da4..52035c79a4a 100644
--- a/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
+++ b/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
@@ -488,6 +488,13 @@ bool ThreadSanitizer::instrumentLoadOrStore(Instruction *I,
   Value *Addr = IsWrite
       ? cast<StoreInst>(I)->getPointerOperand()
       : cast<LoadInst>(I)->getPointerOperand();
+
+  // swifterror memory addresses are mem2reg promoted by instruction selection.
+  // As such they cannot have regular uses like an instrumentation function and
+  // it makes no sense to track them as memory.
+  if (Addr->isSwiftError())
+    return false;
+
   int Idx = getMemoryAccessFuncIndex(Addr, DL);
   if (Idx < 0)
     return false;
diff --git a/test/Instrumentation/ThreadSanitizer/tsan_basic.ll b/test/Instrumentation/ThreadSanitizer/tsan_basic.ll
index 7e049c548f2..61ab98dc999 100644
--- a/test/Instrumentation/ThreadSanitizer/tsan_basic.ll
+++ b/test/Instrumentation/ThreadSanitizer/tsan_basic.ll
@@ -54,5 +54,29 @@ entry:
 ; CHECK: ret void
 }
 
+; CHECK-LABEL: @SwiftError
+; CHECK-NOT: __tsan_read
+; CHECK-NOT: __tsan_write
+; CHECK: ret
+define void @SwiftError(i8** swifterror) sanitize_thread {
+  %swifterror_ptr_value = load i8*, i8** %0
+  store i8* null, i8** %0
+  %swifterror_addr = alloca swifterror i8*
+  %swifterror_ptr_value_2 = load i8*, i8** %swifterror_addr
+  store i8* null, i8** %swifterror_addr
+  ret void
+}
+
+; CHECK-LABEL: @SwiftErrorCall
+; CHECK-NOT: __tsan_read
+; CHECK-NOT: __tsan_write
+; CHECK: ret
+define void @SwiftErrorCall(i8** swifterror) sanitize_thread {
+  %swifterror_addr = alloca swifterror i8*
+  store i8* null, i8** %0
+  call void @SwiftError(i8** %0)
+  ret void
+}
+
 ; CHECK: define internal void @tsan.module_ctor()
 ; CHECK: call void @__tsan_init()