__builtin_object_size refinements. Also handle stack based objects. WIP.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@85174 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 42 insertions, 1 deletions

diff --git a/include/clang/AST/Expr.h b/include/clang/AST/Expr.h
index d63e01dcd0..bcac18ffa2 100644
--- a/include/clang/AST/Expr.h
+++ b/include/clang/AST/Expr.h
@@ -241,6 +241,10 @@ public:
   /// in Result.
   bool Evaluate(EvalResult &Result, ASTContext &Ctx) const;
 
+  /// EvaluateAsAny - The same as Evaluate, except that it also succeeds on
+  /// stack based objects.
+  bool EvaluateAsAny(EvalResult &Result, ASTContext &Ctx) const;
+
   /// isEvaluatable - Call Evaluate to see if this expression can be constant
   /// folded, but discard the result.
   bool isEvaluatable(ASTContext &Ctx) const;
diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp
index 9992b6944e..8435e03417 100644
--- a/lib/AST/ExprConstant.cpp
+++ b/lib/AST/ExprConstant.cpp
@@ -877,7 +877,7 @@ bool IntExprEvaluator::VisitCallExpr(const CallExpr *E) {
   case Builtin::BI__builtin_object_size: {
     const Expr *Arg = E->getArg(0)->IgnoreParens();
     Expr::EvalResult Base;
-    if (Arg->Evaluate(Base, Info.Ctx)
+    if (Arg->EvaluateAsAny(Base, Info.Ctx)
         && Base.Val.getKind() == APValue::LValue
         && !Base.HasSideEffects)
       if (const Expr *LVBase = Base.Val.getLValueBase())
@@ -1830,6 +1830,33 @@ bool Expr::Evaluate(EvalResult &Result, ASTContext &Ctx) const {
   return true;
 }
 
+bool Expr::EvaluateAsAny(EvalResult &Result, ASTContext &Ctx) const {
+  EvalInfo Info(Ctx, Result, true);
+
+  if (getType()->isVectorType()) {
+    if (!EvaluateVector(this, Result.Val, Info))
+      return false;
+  } else if (getType()->isIntegerType()) {
+    if (!IntExprEvaluator(Info, Result.Val).Visit(const_cast<Expr*>(this)))
+      return false;
+  } else if (getType()->hasPointerRepresentation()) {
+    if (!EvaluatePointer(this, Result.Val, Info))
+      return false;
+  } else if (getType()->isRealFloatingType()) {
+    llvm::APFloat f(0.0);
+    if (!EvaluateFloat(this, f, Info))
+      return false;
+
+    Result.Val = APValue(f);
+  } else if (getType()->isAnyComplexType()) {
+    if (!EvaluateComplex(this, Result.Val, Info))
+      return false;
+  } else
+    return false;
+
+  return true;
+}
+
 bool Expr::EvaluateAsLValue(EvalResult &Result, ASTContext &Ctx) const {
   EvalInfo Info(Ctx, Result);
 
diff --git a/test/CodeGen/object-size.c b/test/CodeGen/object-size.c
index 36dc341e93..970d11f6e1 100644
--- a/test/CodeGen/object-size.c
+++ b/test/CodeGen/object-size.c
@@ -47,3 +47,13 @@ void test6() {
   // CHECK:       call    ___inline_strcpy_chk
   strcpy((++i, gbuf), "Hi there");
 }
+
+void test7() {
+  char buf[57];
+
+  // CHECK:       movabsq $53, %rdx
+  // CHECK-NEXT:  movq    %rax, %rdi
+  // CHECK-NEXT:  movq    %rcx, %rsi
+  // CHECK-NEXT:  call    ___strcpy_chk
+  strcpy(&buf[4], "Hi there");
+}