[libFuzzer] Allow non-fuzzer args after -ignore_remaining_args=1

With this change, libFuzzer will ignore any arguments after a sigil
argument, but it will preserve these arguments at the end of the
command line when launching subprocesses. Using this, its possible to
handle positional and single-dash arguments to the program under test
by discarding everything up to -ignore_remaining_args=1 in
LLVMFuzzerInitialize.

llvm-svn: 308069

3 files changed, 44 insertions, 3 deletions

diff --git a/llvm/lib/Fuzzer/test/CMakeLists.txt b/llvm/lib/Fuzzer/test/CMakeLists.txt
index 30566bdc87a..26f392bee91 100644
--- a/llvm/lib/Fuzzer/test/CMakeLists.txt
+++ b/llvm/lib/Fuzzer/test/CMakeLists.txt
@@ -90,6 +90,7 @@ set(Tests
   EmptyTest
   EquivalenceATest
   EquivalenceBTest
+  FlagsTest
   FourIndependentBranchesTest
   FullCoverageSetTest
   InitializeTest
diff --git a/llvm/lib/Fuzzer/test/FlagsTest.cpp b/llvm/lib/Fuzzer/test/FlagsTest.cpp
new file mode 100644
index 00000000000..ac64b9d48df
--- /dev/null
+++ b/llvm/lib/Fuzzer/test/FlagsTest.cpp
@@ -0,0 +1,32 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Parse some flags
+#include <string>
+#include <vector>
+
+static std::vector<std::string> Flags;
+
+extern "C" int LLVMFuzzerInitialize(int *Argc, char ***Argv) {
+  // Parse --flags and anything after -ignore_remaining_args=1 is passed.
+  int I = 1;
+  while (I < *Argc) {
+    std::string S((*Argv)[I++]);
+    if (S == "-ignore_remaining_args=1")
+      break;
+    if (S.substr(0, 2) == "--")
+      Flags.push_back(S);
+  }
+  while (I < *Argc)
+    Flags.push_back(std::string((*Argv)[I++]));
+
+  return 0;
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  fprintf(stderr, "BINGO ");
+  for (auto Flag : Flags)
+    fprintf(stderr, "%s ", Flag.c_str());
+  fprintf(stderr, "\n");
+  exit(0);
+}
diff --git a/llvm/lib/Fuzzer/test/fuzzer-flags.test b/llvm/lib/Fuzzer/test/fuzzer-flags.test
index 76ea2770575..61ce07797b4 100644
--- a/llvm/lib/Fuzzer/test/fuzzer-flags.test
+++ b/llvm/lib/Fuzzer/test/fuzzer-flags.test
@@ -1,10 +1,18 @@
-RUN: LLVMFuzzer-SimpleTest -foo_bar=1 2>&1 | FileCheck %s --check-prefix=FOO_BAR
+RUN: LLVMFuzzer-FlagsTest -foo_bar=1 2>&1 | FileCheck %s --check-prefix=FOO_BAR
 FOO_BAR: WARNING: unrecognized flag '-foo_bar=1'; use -help=1 to list all flags
 FOO_BAR: BINGO
 
-RUN: LLVMFuzzer-SimpleTest -runs=10 --max_len=100 2>&1 | FileCheck %s --check-prefix=DASH_DASH
+RUN: LLVMFuzzer-FlagsTest -runs=10 --max_len=100 2>&1 | FileCheck %s --check-prefix=DASH_DASH
 DASH_DASH: WARNING: did you mean '-max_len=100' (single dash)?
 DASH_DASH: INFO: A corpus is not provided, starting from an empty corpus
 
-RUN: LLVMFuzzer-SimpleTest -help=1 2>&1 | FileCheck %s --check-prefix=NO_INTERNAL
+RUN: LLVMFuzzer-FlagsTest -help=1 2>&1 | FileCheck %s --check-prefix=NO_INTERNAL
 NO_INTERNAL-NOT: internal flag
+
+RUN: LLVMFuzzer-FlagsTest --foo-bar -runs=10 -ignore_remaining_args=1 --baz -help=1 test 2>&1 | FileCheck %s --check-prefix=PASSTHRU
+PASSTHRU: BINGO --foo-bar --baz -help=1 test
+
+RUN: mkdir -p %t/T0 %t/T1
+RUN: touch %t/T1/empty
+RUN: LLVMFuzzer-FlagsTest --foo-bar -merge=1 %t/T0 %t/T1 -ignore_remaining_args=1 --baz -help=1 test 2>&1 | FileCheck %s --check-prefix=PASSTHRU-MERGE
+PASSTHRU-MERGE: BINGO --foo-bar --baz -help=1 test