[dfsan] Treat vararg custom functions like unimplemented functions.

Because declarations of these functions can appear in places like autoconf
checks, they have to be handled somehow, even though we do not support
vararg custom functions. We do so by printing a warning and calling the
uninstrumented function, as we do for unimplemented functions.

llvm-svn: 216042

2 files changed, 7 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
index 3e11efc0e30..9f5e0bb844d 100644
--- a/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
@@ -476,7 +476,7 @@ DataFlowSanitizer::WrapperKind DataFlowSanitizer::getWrapperKind(Function *F) {
     return WK_Functional;
   if (ABIList.isIn(*F, "discard"))
     return WK_Discard;
-  if (ABIList.isIn(*F, "custom"))
+  if (ABIList.isIn(*F, "custom") && !F->isVarArg())
     return WK_Custom;
 
   return WK_Warning;
diff --git a/llvm/test/Instrumentation/DataFlowSanitizer/abilist.ll b/llvm/test/Instrumentation/DataFlowSanitizer/abilist.ll
index 66ddc140a08..53b7d86dbda 100644
--- a/llvm/test/Instrumentation/DataFlowSanitizer/abilist.ll
+++ b/llvm/test/Instrumentation/DataFlowSanitizer/abilist.ll
@@ -16,6 +16,8 @@ declare void @custom1(i32 %a, i32 %b)
 
 declare i32 @custom2(i32 %a, i32 %b)
 
+declare void @custom3(...)
+
 declare void @customcb(i32 (i32)* %cb)
 
 declare i32 @cb(i32)
@@ -33,6 +35,10 @@ define void @f() {
   ; CHECK: call void @__dfsw_customcb({{.*}} @"dfst0$customcb", i8* bitcast ({{.*}} @"dfs$cb" to i8*), i16 0)
   call void @customcb(i32 (i32)* @cb)
 
+  ; CHECK: call void @__dfsan_unimplemented
+  ; CHECK: call void (...)* @custom3()
+  call void (...)* @custom3()
+
   ret void
 }