[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.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173848 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 10 insertions, 3 deletions

diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index 9bef08b4a5..aad877134d 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -1975,6 +1975,13 @@ void CodeGenFunction::EmitCheck(llvm::Value *Checked, StringRef CheckName,
                                 ArrayRef<llvm::Value *> DynamicArgs,
                                 CheckRecoverableKind RecoverKind) {
   assert(SanOpts != &SanitizerOptions::Disabled);
+
+  if (CGM.getCodeGenOpts().SanitizeUndefinedTrapOnError) {
+    assert (RecoverKind != CRK_AlwaysRecoverable &&
+            "Runtime call required for AlwaysRecoverable kind!");
+    return EmitTrapCheck(Checked);
+  }
+
   llvm::BasicBlock *Cont = createBasicBlock("cont");
 
   llvm::BasicBlock *Handler = createBasicBlock("handler." + CheckName);
@@ -2043,7 +2050,7 @@ void CodeGenFunction::EmitCheck(llvm::Value *Checked, StringRef CheckName,
   EmitBlock(Cont);
 }
 
-void CodeGenFunction::EmitTrapvCheck(llvm::Value *Checked) {
+void CodeGenFunction::EmitTrapCheck(llvm::Value *Checked) {
   llvm::BasicBlock *Cont = createBasicBlock("cont");
 
   // If we're optimizing, collapse all calls to trap down to just one per
diff --git a/lib/CodeGen/CGExprScalar.cpp b/lib/CodeGen/CGExprScalar.cpp
index 7f0eda8993..49494be901 100644
--- a/lib/CodeGen/CGExprScalar.cpp
+++ b/lib/CodeGen/CGExprScalar.cpp
@@ -2044,7 +2044,7 @@ Value *ScalarExprEmitter::EmitOverflowCheckedBinOp(const BinOpInfo &Ops) {
     if (!isSigned || CGF.SanOpts->SignedIntegerOverflow)
       EmitBinOpCheck(Builder.CreateNot(overflow), Ops);
     else
-      CGF.EmitTrapvCheck(Builder.CreateNot(overflow));
+      CGF.EmitTrapCheck(Builder.CreateNot(overflow));
     return result;
   }
 
diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index 6f06b3bc26..ce3db3f4ec 100644
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -2606,7 +2606,7 @@ public:
 
   /// \brief Create a basic block that will call the trap intrinsic, and emit a
   /// conditional branch to it, for the -ftrapv checks.
-  void EmitTrapvCheck(llvm::Value *Checked);
+  void EmitTrapCheck(llvm::Value *Checked);
 
   /// EmitCallArg - Emit a single call argument.
   void EmitCallArg(CallArgList &args, const Expr *E, QualType ArgType);