add -fbounds-checking option.

When enabled, clang generates bounds checks for array and pointers dereferences. Work to follow in LLVM's backend.

OK'ed by Chad; thanks for the review.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@156431 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 7 insertions, 1 deletions

diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index f977f5531a..19ee42824f 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -517,7 +517,7 @@ unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
 }
 
 void CodeGenFunction::EmitCheck(llvm::Value *Address, unsigned Size) {
-  if (!CatchUndefined)
+  if (BoundsChecking <= 0)
     return;
 
   // This needs to be to the standard address space.
diff --git a/lib/CodeGen/CodeGenFunction.cpp b/lib/CodeGen/CodeGenFunction.cpp
index dfb04b42aa..5d108be273 100644
--- a/lib/CodeGen/CodeGenFunction.cpp
+++ b/lib/CodeGen/CodeGenFunction.cpp
@@ -41,6 +41,7 @@ CodeGenFunction::CodeGenFunction(CodeGenModule &cgm)
     CXXVTTValue(0), OutermostConditional(0), TerminateLandingPad(0),
     TerminateHandler(0), TrapBB(0) {
 
+  BoundsChecking = getContext().getLangOpts().BoundsChecking;
   CatchUndefined = getContext().getLangOpts().CatchUndefined;
   CGM.getCXXABI().getMangleContext().startNewFunction();
 }
diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index a25b02aac8..8d48a0b24e 100644
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -591,6 +591,11 @@ public:
   /// we prefer to insert allocas.
   llvm::AssertingVH<llvm::Instruction> AllocaInsertPt;
 
+  /// BoundsChecking - Emit run-time bounds checks. Higher values mean
+  /// potentially higher performance penalties.
+  unsigned char BoundsChecking;
+
+  /// CatchUndefined - Emit run-time checks to catch undefined behaviors.
   bool CatchUndefined;
 
   /// In ARC, whether we should autorelease the return value.