[UBSan] Implement runtime suppressions (PR25066).

Summary:
Add the ability to suppress UBSan reports for files/functions/modules
at runtime. The user can now pass UBSAN_OPTIONS=suppressions=supp.txt
with the contents of the form:

signed-integer-overflow:file-with-known-overflow.cpp
alignment:function_doing_unaligned_access
vptr:shared_object_with_vptr_failures.so

Suppression categories match the arguments passed to -fsanitize=
flag (although, see below). There is no overhead if suppressions are
not provided. Otherwise there is extra overhead for symbolization.

Limitations:
1) sometimes suppressions need debug info / symbol table to function
   properly (although sometimes frontend generates enough info to
   do the match).
2) it's only possible to suppress recoverable UB kinds - if you've
   built the code with -fno-sanitize-recover=undefined, suppressions
   will not work.
3) categories are fine-grained check kinds, not groups like "undefined"
   or "integer", so you can't write "undefined:file_with_ub.cc".

Reviewers: rsmith, kcc

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D15363

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@256018 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 4 deletions

diff --git a/lib/ubsan/ubsan_handlers_cxx.cc b/lib/ubsan/ubsan_handlers_cxx.cc
index 7e090827d..3e81be671 100644
--- a/lib/ubsan/ubsan_handlers_cxx.cc
+++ b/lib/ubsan/ubsan_handlers_cxx.cc
@@ -43,10 +43,11 @@ static bool HandleDynamicTypeCacheMiss(
     return false;
 
   SourceLocation Loc = Data->Loc.acquire();
-  if (Loc.isDisabled())
+  ErrorType ET = ErrorType::DynamicTypeMismatch;
+  if (ignoreReport(Loc, Opts, ET))
     return false;
 
-  ScopedReport R(Opts, Loc, ErrorType::DynamicTypeMismatch);
+  ScopedReport R(Opts, Loc, ET);
 
   Diag(Loc, DL_Error,
        "%0 address %1 which does not point to an object of type %2")
@@ -89,10 +90,12 @@ void __ubsan::__ubsan_handle_dynamic_type_cache_miss_abort(
 static void HandleCFIBadType(CFIBadTypeData *Data, ValueHandle Vtable,
                              ReportOptions Opts) {
   SourceLocation Loc = Data->Loc.acquire();
+  ErrorType ET = ErrorType::CFIBadType;
 
-  if (ignoreReport(Loc, Opts))
+  if (ignoreReport(Loc, Opts, ET))
     return;
-  ScopedReport R(Opts, Loc, ErrorType::CFIBadType);
+
+  ScopedReport R(Opts, Loc, ET);
   DynamicTypeInfo DTI = getDynamicTypeInfoFromVtable((void*)Vtable);
 
   static const char *TypeCheckKinds[] = {