[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

1 files changed, 8 insertions, 1 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