1 files changed, 49 insertions, 0 deletions
diff --git a/tools/gwp_asan/stack_trace_compressor_fuzzer.cpp b/tools/gwp_asan/stack_trace_compressor_fuzzer.cpp
new file mode 100644
index 000000000000..aa57fdaff636
--- /dev/null
+++ b/tools/gwp_asan/stack_trace_compressor_fuzzer.cpp
@@ -0,0 +1,49 @@
+#include <cstddef>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <vector>
+
+#include "gwp_asan/stack_trace_compressor.h"
+
+constexpr size_t kBytesForLargestVarInt = (sizeof(uintptr_t) * 8) / 7 + 1;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  size_t BufferSize = kBytesForLargestVarInt * Size / sizeof(uintptr_t);
+  std::vector<uint8_t> Buffer(BufferSize);
+  std::vector<uint8_t> Buffer2(BufferSize);
+
+  // Unpack the fuzz bytes.
+  gwp_asan::compression::unpack(Data, Size,
+                                reinterpret_cast<uintptr_t *>(Buffer2.data()),
+                                BufferSize / sizeof(uintptr_t));
+
+  // Pack the fuzz bytes.
+  size_t BytesWritten = gwp_asan::compression::pack(
+      reinterpret_cast<const uintptr_t *>(Data), Size / sizeof(uintptr_t),
+      Buffer.data(), BufferSize);
+
+  // Unpack the compressed buffer.
+  size_t DecodedElements = gwp_asan::compression::unpack(
+      Buffer.data(), BytesWritten,
+      reinterpret_cast<uintptr_t *>(Buffer2.data()),
+      BufferSize / sizeof(uintptr_t));
+
+  // Ensure that every element was encoded and decoded properly.
+  if (DecodedElements != Size / sizeof(uintptr_t))
+    abort();
+
+  // Ensure that the compression and uncompression resulted in the same trace.
+  const uintptr_t *FuzzPtrs = reinterpret_cast<const uintptr_t *>(Data);
+  const uintptr_t *DecodedPtrs =
+      reinterpret_cast<const uintptr_t *>(Buffer2.data());
+  for (size_t i = 0; i < Size / sizeof(uintptr_t); ++i) {
+    if (FuzzPtrs[i] != DecodedPtrs[i]) {
+      fprintf(stderr, "FuzzPtrs[%zu] != DecodedPtrs[%zu] (0x%zx vs. 0x%zx)", i,
+              i, FuzzPtrs[i], DecodedPtrs[i]);
+      abort();
+    }
+  }
+
+  return 0;
+}