[cfi] Safe handling of unaddressable vtable pointers (compiler-rt).

Avoid crashing when printing diagnostics for vtable-related CFI
errors. In diagnostic mode, the frontend does an additional check of
the vtable pointer against the set of all known vtable addresses and
lets the runtime handler know if it is safe to inspect the vtable.

http://reviews.llvm.org/D16824

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@259717 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 6 deletions

diff --git a/lib/ubsan/ubsan_handlers.cc b/lib/ubsan/ubsan_handlers.cc
index 3b37af669..4ede388e0 100644
--- a/lib/ubsan/ubsan_handlers.cc
+++ b/lib/ubsan/ubsan_handlers.cc
@@ -551,31 +551,33 @@ namespace __ubsan {
 #ifdef UBSAN_CAN_USE_CXXABI
 SANITIZER_WEAK_ATTRIBUTE
 void HandleCFIBadType(CFICheckFailData *Data, ValueHandle Vtable,
-                      ReportOptions Opts);
+                      bool ValidVtable, ReportOptions Opts);
 #else
 static void HandleCFIBadType(CFICheckFailData *Data, ValueHandle Vtable,
-                             ReportOptions Opts) {
+                             bool ValidVtable, ReportOptions Opts) {
   Die();
 }
 #endif
 }  // namespace __ubsan
 
 void __ubsan::__ubsan_handle_cfi_check_fail(CFICheckFailData *Data,
-                                           ValueHandle Value) {
+                                            ValueHandle Value,
+                                            uptr ValidVtable) {
   GET_REPORT_OPTIONS(false);
   if (Data->CheckKind == CFITCK_ICall)
     handleCFIBadIcall(Data, Value, Opts);
   else
-    HandleCFIBadType(Data, Value, Opts);
+    HandleCFIBadType(Data, Value, ValidVtable, Opts);
 }
 
 void __ubsan::__ubsan_handle_cfi_check_fail_abort(CFICheckFailData *Data,
-                                                 ValueHandle Value) {
+                                                  ValueHandle Value,
+                                                  uptr ValidVtable) {
   GET_REPORT_OPTIONS(true);
   if (Data->CheckKind == CFITCK_ICall)
     handleCFIBadIcall(Data, Value, Opts);
   else
-    HandleCFIBadType(Data, Value, Opts);
+    HandleCFIBadType(Data, Value, ValidVtable, Opts);
   Die();
 }