[lib/Fuzzer] use -fsanitize-coverage=trace-cmp when building LLVM with LLVM_USE_SANITIZE_COVERAGE; in lib/Fuzzer try to reload the corpus to pick up new units from other processes

llvm-svn: 236906

1 files changed, 25 insertions, 4 deletions

diff --git a/llvm/lib/Fuzzer/FuzzerIO.cpp b/llvm/lib/Fuzzer/FuzzerIO.cpp
index 81f37aa..7136d38 100644
--- a/llvm/lib/Fuzzer/FuzzerIO.cpp
+++ b/llvm/lib/Fuzzer/FuzzerIO.cpp
@@ -13,10 +13,26 @@
 #include <iterator>
 #include <fstream>
 #include <dirent.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
 namespace fuzzer {
 
-static std::vector<std::string> ListFilesInDir(const std::string &Dir) {
+static long GetEpoch(const std::string &Path) {
+  struct stat St;
+  if (stat(Path.c_str(), &St)) return 0;
+  return St.st_mtime;
+}
+
+static std::vector<std::string> ListFilesInDir(const std::string &Dir,
+                                               long *Epoch) {
   std::vector<std::string> V;
+  if (Epoch) {
+    auto E = GetEpoch(Dir.c_str());
+    if (*Epoch >= E) return V;
+    *Epoch = E;
+  }
   DIR *D = opendir(Dir.c_str());
   if (!D) return V;
   while (auto E = readdir(D)) {
@@ -50,9 +66,14 @@ void WriteToFile(const Unit &U, const std::string &Path) {
   OF.write((const char*)U.data(), U.size());
 }
 
-void ReadDirToVectorOfUnits(const char *Path, std::vector<Unit> *V) {
-  for (auto &X : ListFilesInDir(Path))
-    V->push_back(FileToVector(DirPlusFile(Path, X)));
+void ReadDirToVectorOfUnits(const char *Path, std::vector<Unit> *V,
+                            long *Epoch) {
+  long E = Epoch ? *Epoch : 0;
+  for (auto &X : ListFilesInDir(Path, Epoch)) {
+    auto FilePath = DirPlusFile(Path, X);
+    if (Epoch && GetEpoch(FilePath) < E) continue;
+    V->push_back(FileToVector(FilePath));
+  }
 }
 
 std::string DirPlusFile(const std::string &DirPath,