Introduce -fsanitize-trap= flag.

This flag controls whether a given sanitizer traps upon detecting
an error. It currently only supports UBSan. The existing flag
-fsanitize-undefined-trap-on-error has been made an alias of
-fsanitize-trap=undefined.

This change also cleans up some awkward behavior around the combination
of -fsanitize-trap=undefined and -fsanitize=undefined. Previously we
would reject command lines containing the combination of these two flags,
as -fsanitize=vptr is not compatible with trapping. This required the
creation of -fsanitize=undefined-trap, which excluded -fsanitize=vptr
(and -fsanitize=function, but this seems like an oversight).

Now, -fsanitize=undefined is an alias for -fsanitize=undefined-trap,
and if -fsanitize-trap=undefined is specified, we treat -fsanitize=vptr
as an "unsupported" flag, which means that we error out if the flag is
specified explicitly, but implicitly disable it if the flag was implied
by -fsanitize=undefined.

Differential Revision: http://reviews.llvm.org/D10464

llvm-svn: 240105

1 files changed, 12 insertions, 12 deletions

diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 1ed45a33d0f..85746aea04b 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -2300,15 +2300,24 @@ void CodeGenFunction::EmitCheck(
 
   llvm::Value *FatalCond = nullptr;
   llvm::Value *RecoverableCond = nullptr;
+  llvm::Value *TrapCond = nullptr;
   for (int i = 0, n = Checked.size(); i < n; ++i) {
     llvm::Value *Check = Checked[i].first;
+    // -fsanitize-trap= overrides -fsanitize-recover=.
     llvm::Value *&Cond =
-        CGM.getCodeGenOpts().SanitizeRecover.has(Checked[i].second)
-            ? RecoverableCond
-            : FatalCond;
+        CGM.getCodeGenOpts().SanitizeTrap.has(Checked[i].second)
+            ? TrapCond
+            : CGM.getCodeGenOpts().SanitizeRecover.has(Checked[i].second)
+                  ? RecoverableCond
+                  : FatalCond;
     Cond = Cond ? Builder.CreateAnd(Cond, Check) : Check;
   }
 
+  if (TrapCond)
+    EmitTrapCheck(TrapCond);
+  if (!FatalCond && !RecoverableCond)
+    return;
+
   llvm::Value *JointCond;
   if (FatalCond && RecoverableCond)
     JointCond = Builder.CreateAnd(FatalCond, RecoverableCond);
@@ -2326,15 +2335,6 @@ void CodeGenFunction::EmitCheck(
   }
 #endif
 
-  if (CGM.getCodeGenOpts().SanitizeUndefinedTrapOnError) {
-    assert(RecoverKind != CheckRecoverableKind::AlwaysRecoverable &&
-           "Runtime call required for AlwaysRecoverable kind!");
-    // Assume that -fsanitize-undefined-trap-on-error overrides
-    // -fsanitize-recover= options, as we can only print meaningful error
-    // message and recover if we have a runtime support.
-    return EmitTrapCheck(JointCond);
-  }
-
   llvm::BasicBlock *Cont = createBasicBlock("cont");
   llvm::BasicBlock *Handlers = createBasicBlock("handler." + CheckName);
   llvm::Instruction *Branch = Builder.CreateCondBr(JointCond, Cont, Handlers);