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

llvm/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;

llvm/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()