[ubsan] Implement the -fcatch-undefined-behavior flag using a trapping

implementation; this is much more inline with the original implementation
(i.e., pre-ubsan) and does not require run-time library support.

The trapping implementation can be invoked using either '-fcatch-undefined-behavior'
or '-fsanitize=undefined-trap -fsanitize-undefined-trap-on-error', with the latter
being preferred.  Eventually, the -fcatch-undefined-behavior' flag will be removed.

llvm-svn: 173848

1 files changed, 13 insertions, 5 deletions

diff --git a/clang/lib/Driver/SanitizerArgs.h b/clang/lib/Driver/SanitizerArgs.h
index a2819598911..bc3aa58331d 100644
--- a/clang/lib/Driver/SanitizerArgs.h
+++ b/clang/lib/Driver/SanitizerArgs.h
@@ -36,25 +36,32 @@ class SanitizerArgs {
     NeedsAsanRt = Address,
     NeedsTsanRt = Thread,
     NeedsMsanRt = Memory,
-    NeedsUbsanRt = (Undefined & ~Bounds) | Integer
+    NeedsUbsanRt = (Undefined & ~Bounds) | Integer,
+    NotAllowedWithTrap = Vptr
   };
   unsigned Kind;
   std::string BlacklistFile;
   bool MsanTrackOrigins;
   bool AsanZeroBaseShadow;
+  bool UbsanTrapOnError;
 
  public:
   SanitizerArgs() : Kind(0), BlacklistFile(""), MsanTrackOrigins(false),
-                    AsanZeroBaseShadow(false) {}
+                    AsanZeroBaseShadow(false), UbsanTrapOnError(false) {}
   /// Parses the sanitizer arguments from an argument list.
   SanitizerArgs(const Driver &D, const ArgList &Args);
 
   bool needsAsanRt() const { return Kind & NeedsAsanRt; }
   bool needsTsanRt() const { return Kind & NeedsTsanRt; }
   bool needsMsanRt() const { return Kind & NeedsMsanRt; }
-  bool needsUbsanRt() const { return Kind & NeedsUbsanRt; }
+  bool needsUbsanRt() const {
+    if (UbsanTrapOnError)
+      return false;
+    return Kind & NeedsUbsanRt;
+  }
 
   bool sanitizesVptr() const { return Kind & Vptr; }
+  bool notAllowedWithTrap() const { return Kind & NotAllowedWithTrap; }
 
   void addArgs(const ArgList &Args, ArgStringList &CmdArgs) const {
     if (!Kind)
@@ -127,8 +134,9 @@ class SanitizerArgs {
       Remove = Thread;
       DeprecatedReplacement = "-fno-sanitize=thread";
     } else if (A->getOption().matches(options::OPT_fcatch_undefined_behavior)) {
-      Add = Undefined;
-      DeprecatedReplacement = "-fsanitize=undefined";
+      Add = UndefinedTrap;
+      DeprecatedReplacement = 
+        "-fsanitize=undefined-trap -fsanitize-undefined-trap-on-error";
     } else if (A->getOption().matches(options::OPT_fbounds_checking) ||
                A->getOption().matches(options::OPT_fbounds_checking_EQ)) {
       Add = Bounds;