hwasan: Enable -hwasan-allow-ifunc by default.

It's been on in Android for a while without causing problems, so it's time
to make it the default and remove the flag.

Differential Revision: https://reviews.llvm.org/D60355

llvm-svn: 357960
diff --git a/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
index 6ecbd23..71eaf46 100644
--- a/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
@@ -160,10 +160,6 @@
                                        cl::desc("inline all checks"),
                                        cl::Hidden, cl::init(false));
 
-static cl::opt<bool> ClAllowIfunc("hwasan-allow-ifunc",
-                                  cl::desc("allow the use of ifunc"),
-                                  cl::Hidden, cl::init(false));
-
 namespace {
 
 /// An instrumentation pass implementing detection of addressability bugs
@@ -836,7 +832,7 @@
   if (!Mapping.InTls)
     return getDynamicShadowNonTls(IRB);
 
-  if (ClAllowIfunc && !WithFrameRecord && TargetTriple.isAndroid())
+  if (!WithFrameRecord && TargetTriple.isAndroid())
     return getDynamicShadowIfunc(IRB);
 
   Value *SlotPtr = getHwasanThreadSlotPtr(IRB, IntptrTy);