[dfsan] Initial set of DFSAN_OPTIONS flags.

llvm-svn: 190379

4 files changed, 66 insertions, 3 deletions

diff --git a/compiler-rt/lib/dfsan/dfsan.cc b/compiler-rt/lib/dfsan/dfsan.cc
index c4d13f7d7cc..76c392d14b1 100644
--- a/compiler-rt/lib/dfsan/dfsan.cc
+++ b/compiler-rt/lib/dfsan/dfsan.cc
@@ -22,6 +22,7 @@
 #include "sanitizer/dfsan_interface.h"
 #include "sanitizer_common/sanitizer_atomic.h"
 #include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_flags.h"
 #include "sanitizer_common/sanitizer_libc.h"
 
 #include "dfsan/dfsan.h"
@@ -36,6 +37,8 @@ static const uptr kNumLabels = 1 << (sizeof(dfsan_label) * 8);
 static atomic_dfsan_label __dfsan_last_label;
 static dfsan_label_info __dfsan_label_info[kNumLabels];
 
+Flags __dfsan::flags_data;
+
 SANITIZER_INTERFACE_ATTRIBUTE THREADLOCAL dfsan_label __dfsan_retval_tls;
 SANITIZER_INTERFACE_ATTRIBUTE THREADLOCAL dfsan_label __dfsan_arg_tls[64];
 
@@ -132,14 +135,18 @@ dfsan_label __dfsan_union_load(const dfsan_label *ls, size_t n) {
 
 extern "C" SANITIZER_INTERFACE_ATTRIBUTE
 void __dfsan_unimplemented(char *fname) {
-  Report("WARNING: DataFlowSanitizer: call to uninstrumented function %s\n",
-         fname);
+  if (flags().warn_unimplemented)
+    Report("WARNING: DataFlowSanitizer: call to uninstrumented function %s\n",
+           fname);
 }
 
 // Use '-mllvm -dfsan-debug-nonzero-labels' and break on this function
 // to try to figure out where labels are being introduced in a nominally
 // label-free program.
-extern "C" SANITIZER_INTERFACE_ATTRIBUTE void __dfsan_nonzero_label() {}
+extern "C" SANITIZER_INTERFACE_ATTRIBUTE void __dfsan_nonzero_label() {
+  if (flags().warn_nonzero_labels)
+    Report("WARNING: DataFlowSanitizer: saw nonzero label\n");
+}
 
 // Like __dfsan_union, but for use from the client or custom functions.  Hence
 // the equality comparison is done here before calling __dfsan_union.
@@ -222,6 +229,14 @@ dfsan_label dfsan_has_label_with_desc(dfsan_label label, const char *desc) {
   }
 }
 
+static void InitializeFlags(Flags &f, const char *env) {
+  f.warn_unimplemented = true;
+  f.warn_nonzero_labels = false;
+
+  ParseFlag(env, &f.warn_unimplemented, "warn_unimplemented");
+  ParseFlag(env, &f.warn_nonzero_labels, "warn_nonzero_labels");
+}
+
 #ifdef DFSAN_NOLIBC
 extern "C" void dfsan_init() {
 #else
@@ -238,6 +253,8 @@ static void dfsan_init(int argc, char **argv, char **envp) {
   if (!(init_addr >= kUnusedAddr && init_addr < kAppAddr))
     Mprotect(kUnusedAddr, kAppAddr - kUnusedAddr);
 
+  InitializeFlags(flags(), GetEnv("DFSAN_OPTIONS"));
+
   InitializeInterceptors();
 }
 
diff --git a/compiler-rt/lib/dfsan/dfsan.h b/compiler-rt/lib/dfsan/dfsan.h
index 0be55aa71a6..7d023ed322c 100644
--- a/compiler-rt/lib/dfsan/dfsan.h
+++ b/compiler-rt/lib/dfsan/dfsan.h
@@ -29,6 +29,18 @@ inline const dfsan_label *shadow_for(const void *ptr) {
   return shadow_for(const_cast<void *>(ptr));
 }
 
+struct Flags {
+  // Whether to warn on unimplemented functions.
+  bool warn_unimplemented;
+  // Whether to warn on non-zero labels.
+  bool warn_nonzero_labels;
+};
+
+extern Flags flags_data;
+inline Flags &flags() {
+  return flags_data;
+}
+
 }  // namespace __dfsan
 
 #endif  // DFSAN_H
diff --git a/compiler-rt/lib/dfsan/lit_tests/Inputs/flags_abilist.txt b/compiler-rt/lib/dfsan/lit_tests/Inputs/flags_abilist.txt
new file mode 100644
index 00000000000..94b1fa29825
--- /dev/null
+++ b/compiler-rt/lib/dfsan/lit_tests/Inputs/flags_abilist.txt
@@ -0,0 +1,10 @@
+fun:f=uninstrumented
+
+fun:main=uninstrumented
+fun:main=discard
+
+fun:dfsan_create_label=uninstrumented
+fun:dfsan_create_label=discard
+
+fun:dfsan_set_label=uninstrumented
+fun:dfsan_set_label=discard
diff --git a/compiler-rt/lib/dfsan/lit_tests/flags.c b/compiler-rt/lib/dfsan/lit_tests/flags.c
new file mode 100644
index 00000000000..5cf970dce90
--- /dev/null
+++ b/compiler-rt/lib/dfsan/lit_tests/flags.c
@@ -0,0 +1,24 @@
+// RUN: %clang_dfsan -m64 %s -fsanitize-blacklist=%S/Inputs/flags_abilist.txt -mllvm -dfsan-debug-nonzero-labels -o %t && %t 2>&1 | FileCheck %s
+// RUN: %clang_dfsan -m64 %s -fsanitize-blacklist=%S/Inputs/flags_abilist.txt -mllvm -dfsan-debug-nonzero-labels -o %t && DFSAN_OPTIONS=warn_unimplemented=0 %t 2>&1 | count 0
+// RUN: %clang_dfsan -m64 %s -fsanitize-blacklist=%S/Inputs/flags_abilist.txt -mllvm -dfsan-debug-nonzero-labels -o %t && DFSAN_OPTIONS=warn_nonzero_labels=1 %t 2>&1 | FileCheck --check-prefix=CHECK-NONZERO %s
+
+// Tests that flags work correctly.
+
+#include <sanitizer/dfsan_interface.h>
+
+int f(int i) {
+  return i;
+}
+
+int main(void) {
+  int i = 1;
+  dfsan_label i_label = dfsan_create_label("i", 0);
+  dfsan_set_label(i_label, &i, sizeof(i));
+
+  // CHECK: WARNING: DataFlowSanitizer: call to uninstrumented function f
+  // CHECK-NOT: WARNING: DataFlowSanitizer: saw nonzero label
+  // CHECK-NONZERO: WARNING: DataFlowSanitizer: saw nonzero label
+  f(i);
+
+  return 0;
+}