[ubsan] Runtime support for pointer overflow checking

Patch by John Regehr and Will Dietz!

Differential Revision: https://reviews.llvm.org/D20323

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@304461 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 31 insertions, 0 deletions

diff --git a/lib/ubsan/ubsan_handlers.cc b/lib/ubsan/ubsan_handlers.cc
index d6a8f52a2..80cc8ad25 100644
--- a/lib/ubsan/ubsan_handlers.cc
+++ b/lib/ubsan/ubsan_handlers.cc
@@ -554,6 +554,37 @@ void __ubsan::__ubsan_handle_nullability_arg_abort(NonNullArgData *Data) {
   Die();
 }
 
+static void handlePointerOverflowImpl(PointerOverflowData *Data,
+                                      ValueHandle Base,
+                                      ValueHandle Result,
+                                      ReportOptions Opts) {
+  SourceLocation Loc = Data->Loc.acquire();
+  ErrorType ET = ErrorType::PointerOverflow;
+
+  if (ignoreReport(Loc, Opts, ET))
+    return;
+
+  ScopedReport R(Opts, Loc, ET);
+
+  Diag(Loc, DL_Error, "pointer index expression with base %0 overflowed to %1")
+    << (void *)Base << (void*)Result;
+}
+
+void __ubsan::__ubsan_handle_pointer_overflow(PointerOverflowData *Data,
+                                              ValueHandle Base,
+                                              ValueHandle Result) {
+  GET_REPORT_OPTIONS(false);
+  handlePointerOverflowImpl(Data, Base, Result, Opts);
+}
+
+void __ubsan::__ubsan_handle_pointer_overflow_abort(PointerOverflowData *Data,
+                                                    ValueHandle Base,
+                                                    ValueHandle Result) {
+  GET_REPORT_OPTIONS(true);
+  handlePointerOverflowImpl(Data, Base, Result, Opts);
+  Die();
+}
+
 static void handleCFIBadIcall(CFICheckFailData *Data, ValueHandle Function,
                               ReportOptions Opts) {
   if (Data->CheckKind != CFITCK_ICall)