[libFuzzer] Replace -seed_corpus to better support fork mode on Win

Summary:
Pass seed corpus list in a file to get around argument length limits on Windows.
This limit was preventing many uses of fork mode on Windows.

Reviewers: kcc, morehouse

Reviewed By: kcc

Subscribers: #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D60980

llvm-svn: 359610

1 files changed, 7 insertions, 2 deletions

diff --git a/compiler-rt/lib/fuzzer/FuzzerFork.cpp b/compiler-rt/lib/fuzzer/FuzzerFork.cpp
index 9d338aa4708..dd16ec1e288 100644
--- a/compiler-rt/lib/fuzzer/FuzzerFork.cpp
+++ b/compiler-rt/lib/fuzzer/FuzzerFork.cpp
@@ -66,6 +66,7 @@ struct FuzzJob {
   std::string CorpusDir;
   std::string FeaturesDir;
   std::string LogPath;
+  std::string SeedListPath;
   std::string CFPath;
 
   // Fuzzing Outputs.
@@ -74,6 +75,7 @@ struct FuzzJob {
   ~FuzzJob() {
     RemoveFile(CFPath);
     RemoveFile(LogPath);
+    RemoveFile(SeedListPath);
     RmDirRecursive(CorpusDir);
     RmDirRecursive(FeaturesDir);
   }
@@ -121,8 +123,11 @@ struct GlobalEnv {
       for (size_t i = 0; i < CorpusSubsetSize; i++)
         Seeds += (Seeds.empty() ? "" : ",") +
                  Files[Rand->SkewTowardsLast(Files.size())];
-    if (!Seeds.empty())
-      Cmd.addFlag("seed_inputs", Seeds);
+    if (!Seeds.empty()) {
+      Job->SeedListPath = std::to_string(JobId) + ".seeds";
+      WriteToFile(Seeds, Job->SeedListPath);
+      Cmd.addFlag("seed_inputs", "@" + Job->SeedListPath);
+    }
     Job->LogPath = DirPlusFile(TempDir, std::to_string(JobId) + ".log");
     Job->CorpusDir = DirPlusFile(TempDir, "C" + std::to_string(JobId));
     Job->FeaturesDir = DirPlusFile(TempDir, "F" + std::to_string(JobId));