[compiler-rt] r335762 - [UBSan] Add silence_unsigned_overflow flag.

[Matt Morehouse via llvm-commits]

Author: morehouse
Date: Wed Jun 27 11:24:46 2018
New Revision: 335762

URL: http://llvm.org/viewvc/llvm-project?rev=335762&view=rev
Log:
[UBSan] Add silence_unsigned_overflow flag.

Summary:
Setting UBSAN_OPTIONS=silence_unsigned_overflow=1 will silence all UIO
reports.  This feature, combined with
-fsanitize-recover=unsigned-integer-overflow, is useful for providing
fuzzing signal without the excessive log output.

Helps with https://github.com/google/oss-fuzz/issues/910.

Reviewers: kcc, vsk

Reviewed By: vsk

Subscribers: vsk, kubamracek, Dor1s, llvm-commits

Differential Revision: https://reviews.llvm.org/D48660

Modified:
    compiler-rt/trunk/lib/ubsan/ubsan_flags.inc
    compiler-rt/trunk/lib/ubsan/ubsan_handlers.cc
    compiler-rt/trunk/test/ubsan/TestCases/Integer/no-recover.cpp

Modified: compiler-rt/trunk/lib/ubsan/ubsan_flags.inc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/ubsan/ubsan_flags.inc?rev=335762&r1=335761&r2=335762&view=diff
==============================================================================
--- compiler-rt/trunk/lib/ubsan/ubsan_flags.inc (original)
+++ compiler-rt/trunk/lib/ubsan/ubsan_flags.inc Wed Jun 27 11:24:46 2018
@@ -24,3 +24,6 @@ UBSAN_FLAG(bool, print_stacktrace, false
 UBSAN_FLAG(const char *, suppressions, "", "Suppressions file name.")
 UBSAN_FLAG(bool, report_error_type, false,
         "Print specific error type instead of 'undefined-behavior' in summary.")
+UBSAN_FLAG(bool, silence_unsigned_overflow, false,
+	"Do not print error reports for unsigned integer overflow. "
+	"Used to provide fuzzing signal without blowing up logs.")

Modified: compiler-rt/trunk/lib/ubsan/ubsan_handlers.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/ubsan/ubsan_handlers.cc?rev=335762&r1=335761&r2=335762&view=diff
==============================================================================
--- compiler-rt/trunk/lib/ubsan/ubsan_handlers.cc (original)
+++ compiler-rt/trunk/lib/ubsan/ubsan_handlers.cc Wed Jun 27 11:24:46 2018
@@ -15,6 +15,7 @@
 #if CAN_SANITIZE_UB
 #include "ubsan_handlers.h"
 #include "ubsan_diag.h"
+#include "ubsan_flags.h"
 #include "ubsan_monitor.h"
 
 #include "sanitizer_common/sanitizer_common.h"
@@ -118,6 +119,9 @@ static void handleIntegerOverflowImpl(Ov
   if (ignoreReport(Loc, Opts, ET))
     return;
 
+  if (!IsSigned && flags()->silence_unsigned_overflow)
+    return;
+
   ScopedReport R(Opts, Loc, ET);
 
   Diag(Loc, DL_Error, ET, "%0 integer overflow: "

Modified: compiler-rt/trunk/test/ubsan/TestCases/Integer/no-recover.cpp
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/ubsan/TestCases/Integer/no-recover.cpp?rev=335762&r1=335761&r2=335762&view=diff
==============================================================================
--- compiler-rt/trunk/test/ubsan/TestCases/Integer/no-recover.cpp (original)
+++ compiler-rt/trunk/test/ubsan/TestCases/Integer/no-recover.cpp Wed Jun 27 11:24:46 2018
@@ -1,5 +1,6 @@
 // RUN: %clangxx -fsanitize=unsigned-integer-overflow %s -o %t && %run %t 2>&1 | FileCheck %s --check-prefix=RECOVER
 // RUN: %clangxx -fsanitize=unsigned-integer-overflow -fno-sanitize-recover=all -fsanitize-recover=unsigned-integer-overflow %s -o %t && %run %t 2>&1 | FileCheck %s --check-prefix=RECOVER
+// RUN: %env_ubsan_opts=silence_unsigned_overflow=1 %run %t 2>&1 | FileCheck %s --check-prefix=SILENT-RECOVER --allow-empty
 // RUN: %clangxx -fsanitize=unsigned-integer-overflow -fno-sanitize-recover=unsigned-integer-overflow %s -o %t && not %run %t 2>&1 | FileCheck %s --check-prefix=ABORT
 
 #include <stdint.h>
@@ -18,5 +19,6 @@ int main() {
 
   (void)(uint64_t(10000000000000000000ull) + uint64_t(9000000000000000000ull));
   // RECOVER: 10000000000000000000 + 9000000000000000000 cannot be represented in type 'unsigned {{long( long)?}}'
+  // SILENT-RECOVER-NOT: runtime error
   // ABORT-NOT: runtime error
 }