Split -fsanitize=bounds to -fsanitize=array-bounds (for the frontend-inserted

check using the ubsan runtime) and -fsanitize=local-bounds (for the middle-end
check which inserts traps).

Remove -fsanitize=local-bounds from -fsanitize=undefined. It does not produce
useful diagnostics and has false positives (PR17635), and is not a good
compromise position between UBSan's checks and ASan's checks.

Map -fbounds-checking to -fsanitize=local-bounds to restore Clang's historical
behavior for that flag.

llvm-svn: 193205

4 files changed, 9 insertions, 8 deletions

diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 9943287adf5..7a62e4e1955 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -245,7 +245,7 @@ void EmitAssemblyHelper::CreatePasses(TargetMachine *TM) {
                            addObjCARCOptPass);
   }
 
-  if (LangOpts.Sanitize.Bounds) {
+  if (LangOpts.Sanitize.LocalBounds) {
     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
                            addBoundsCheckingPass);
     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 4397c2dabef..221d132ee0b 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -641,7 +641,8 @@ static llvm::Value *getArrayIndexingBound(
 void CodeGenFunction::EmitBoundsCheck(const Expr *E, const Expr *Base,
                                       llvm::Value *Index, QualType IndexType,
                                       bool Accessed) {
-  assert(SanOpts->Bounds && "should not be called unless adding bounds checks");
+  assert(SanOpts->ArrayBounds &&
+         "should not be called unless adding bounds checks");
 
   QualType IndexedType;
   llvm::Value *Bound = getArrayIndexingBound(*this, Base, IndexedType);
@@ -742,7 +743,7 @@ LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
 
 LValue CodeGenFunction::EmitCheckedLValue(const Expr *E, TypeCheckKind TCK) {
   LValue LV;
-  if (SanOpts->Bounds && isa<ArraySubscriptExpr>(E))
+  if (SanOpts->ArrayBounds && isa<ArraySubscriptExpr>(E))
     LV = EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E), /*Accessed*/true);
   else
     LV = EmitLValue(E);
@@ -2233,7 +2234,7 @@ LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E,
   QualType IdxTy  = E->getIdx()->getType();
   bool IdxSigned = IdxTy->isSignedIntegerOrEnumerationType();
 
-  if (SanOpts->Bounds)
+  if (SanOpts->ArrayBounds)
     EmitBoundsCheck(E, E->getBase(), Idx, IdxTy, Accessed);
 
   // If the base is a vector type, then we are forming a vector element lvalue
diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index 074fc76616b..f3fd60498ca 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -1073,7 +1073,7 @@ Value *ScalarExprEmitter::VisitArraySubscriptExpr(ArraySubscriptExpr *E) {
   Value *Idx  = Visit(E->getIdx());
   QualType IdxTy = E->getIdx()->getType();
 
-  if (CGF.SanOpts->Bounds)
+  if (CGF.SanOpts->ArrayBounds)
     CGF.EmitBoundsCheck(E, E->getBase(), Idx, IdxTy, /*Accessed*/true);
 
   bool IdxSigned = IdxTy->isSignedIntegerOrEnumerationType();
@@ -2314,7 +2314,7 @@ static Value *emitPointerArithmetic(CodeGenFunction &CGF,
   if (isSubtraction)
     index = CGF.Builder.CreateNeg(index, "idx.neg");
 
-  if (CGF.SanOpts->Bounds)
+  if (CGF.SanOpts->ArrayBounds)
     CGF.EmitBoundsCheck(op.E, pointerOperand, index, indexOperand->getType(),
                         /*Accessed*/ false);
 
diff --git a/clang/lib/Driver/SanitizerArgs.cpp b/clang/lib/Driver/SanitizerArgs.cpp
index 6a919985765..8c9baa7714d 100644
--- a/clang/lib/Driver/SanitizerArgs.cpp
+++ b/clang/lib/Driver/SanitizerArgs.cpp
@@ -256,8 +256,8 @@ bool SanitizerArgs::parse(const Driver &D, const llvm::opt::ArgList &Args,
       "-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;
-    DeprecatedReplacement = "-fsanitize=bounds";
+    Add = LocalBounds;
+    DeprecatedReplacement = "-fsanitize=local-bounds";
   } else if (A->getOption().matches(options::OPT_fsanitize_EQ)) {
     Add = parse(D, A, DiagnoseErrors);
   } else if (A->getOption().matches(options::OPT_fno_sanitize_EQ)) {