5 files changed, 31 insertions, 2 deletions
diff --git a/llvm/lib/Fuzzer/test/CMakeLists.txt b/llvm/lib/Fuzzer/test/CMakeLists.txt
index 5247f00..4cff70c 100644
--- a/llvm/lib/Fuzzer/test/CMakeLists.txt
+++ b/llvm/lib/Fuzzer/test/CMakeLists.txt
@@ -7,6 +7,7 @@ set(CMAKE_CXX_FLAGS_RELEASE "${LIBFUZZER_FLAGS_BASE} -O0 -fsanitize-coverage=edg
 set(DFSanTests
   MemcmpTest
   SimpleCmpTest
+  StrncmpTest
   )
 
 set(Tests
@@ -19,6 +20,7 @@ set(Tests
   NullDerefTest
   SimpleCmpTest
   SimpleTest
+  StrncmpTest
   TimeoutTest
   )
 
diff --git a/llvm/lib/Fuzzer/test/MemcmpTest.cpp b/llvm/lib/Fuzzer/test/MemcmpTest.cpp
index cabdff8f..2954b6c 100644
--- a/llvm/lib/Fuzzer/test/MemcmpTest.cpp
+++ b/llvm/lib/Fuzzer/test/MemcmpTest.cpp
@@ -9,8 +9,10 @@ extern "C" void LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
   if (Size >= 8 && memcmp(Data, "01234567", 8) == 0) {
     if (Size >= 12 && memcmp(Data + 8, "ABCD", 4) == 0) {
       if (Size >= 14 && memcmp(Data + 12, "XY", 2) == 0) {
-        fprintf(stderr, "BINGO\n");
-        exit(1);
+        if (Size >= 16 && memcmp(Data + 14, "KLM", 3) == 0) {
+          fprintf(stderr, "BINGO\n");
+          exit(1);
+        }
       }
     }
   }
diff --git a/llvm/lib/Fuzzer/test/StrncmpTest.cpp b/llvm/lib/Fuzzer/test/StrncmpTest.cpp
new file mode 100644
index 0000000..86b02d0
--- /dev/null
+++ b/llvm/lib/Fuzzer/test/StrncmpTest.cpp
@@ -0,0 +1,20 @@
+// Simple test for a fuzzer. The fuzzer must find a particular string.
+#include <cstring>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+
+extern "C" void LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  // TODO: check other sizes.
+  char *S = (char*)Data;
+  if (Size >= 8 && strncmp(S, "01234567", 8) == 0) {
+    if (Size >= 12 && strncmp(S + 8, "ABCD", 4) == 0) {
+      if (Size >= 14 && strncmp(S + 12, "XY", 2) == 0) {
+        if (Size >= 16 && strncmp(S + 14, "KLM", 3) == 0) {
+          fprintf(stderr, "BINGO\n");
+          exit(1);
+        }
+      }
+    }
+  }
+}
diff --git a/llvm/lib/Fuzzer/test/fuzzer-dfsan.test b/llvm/lib/Fuzzer/test/fuzzer-dfsan.test
index 9a3c9e0..5e41a9e 100644
--- a/llvm/lib/Fuzzer/test/fuzzer-dfsan.test
+++ b/llvm/lib/Fuzzer/test/fuzzer-dfsan.test
@@ -7,3 +7,5 @@ RUN: LLVMFuzzer-SimpleCmpTest-DFSan -use_traces=1 -seed=1 -runs=100 -timeout=5 -
 RUN: not LLVMFuzzer-MemcmpTest-DFSan -use_traces=1 -seed=1 -runs=1000 -timeout=5 2>&1 | FileCheck %s
 RUN: LLVMFuzzer-MemcmpTest-DFSan -use_traces=1 -seed=1 -runs=2 -timeout=5 -verbosity=3 2>&1 | FileCheck %s  -check-prefix=CHECK_DFSanCmpCallback
 
+RUN: not LLVMFuzzer-StrncmpTest-DFSan -use_traces=1 -seed=1 -runs=1000 -timeout=5 2>&1 | FileCheck %s
+RUN: LLVMFuzzer-StrncmpTest-DFSan -use_traces=1 -seed=1 -runs=2 -timeout=5 -verbosity=3 2>&1 | FileCheck %s  -check-prefix=CHECK_DFSanCmpCallback
diff --git a/llvm/lib/Fuzzer/test/fuzzer.test b/llvm/lib/Fuzzer/test/fuzzer.test
index fdabbb1..d6dd3ff 100644
--- a/llvm/lib/Fuzzer/test/fuzzer.test
+++ b/llvm/lib/Fuzzer/test/fuzzer.test
@@ -28,3 +28,6 @@ RUN: not LLVMFuzzer-UserSuppliedFuzzerTest -seed=1 -timeout=15 2>&1 | FileCheck
 RUN: not LLVMFuzzer-MemcmpTest -use_traces=1 -seed=1 -runs=10000    2>&1 | FileCheck %s
 RUN:     LLVMFuzzer-MemcmpTest               -seed=1 -runs=1000000  2>&1 | FileCheck %s --check-prefix=Done1000000
 Done1000000: Done 1000000 runs in
+
+RUN: not LLVMFuzzer-StrncmpTest -use_traces=1 -seed=1 -runs=10000    2>&1 | FileCheck %s
+RUN:     LLVMFuzzer-StrncmpTest               -seed=1 -runs=1000000  2>&1 | FileCheck %s --check-prefix=Done1000000