diff options
| -rw-r--r-- | clang/lib/Sema/SemaChecking.cpp | 12 | ||||
| -rw-r--r-- | clang/test/SemaCXX/array-bounds.cpp | 9 |
2 files changed, 19 insertions, 2 deletions
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp index b06f793b17a..9fe65c1dce4 100644 --- a/clang/lib/Sema/SemaChecking.cpp +++ b/clang/lib/Sema/SemaChecking.cpp @@ -12379,10 +12379,19 @@ void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr, BaseExpr->getType()->getPointeeOrArrayElementType(); BaseExpr = BaseExpr->IgnoreParenCasts(); const ConstantArrayType *ArrayTy = - Context.getAsConstantArrayType(BaseExpr->getType()); + Context.getAsConstantArrayType(BaseExpr->getType()); + if (!ArrayTy) return; + const Type *BaseType = ArrayTy->getElementType().getTypePtr(); + // It is possible that the type of the base expression after IgnoreParenCasts + // is incomplete, even though the type of the base expression before + // IgnoreParenCasts is complete (see PR39746 for an example). In this case we + // have no information about whether the array access is out-of-bounds. + if (BaseType->isIncompleteType()) + return; + Expr::EvalResult Result; if (!IndexExpr->EvaluateAsInt(Result, Context, Expr::SE_AllowSideEffects)) return; @@ -12402,7 +12411,6 @@ void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr, if (!size.isStrictlyPositive()) return; - const Type *BaseType = BaseExpr->getType()->getPointeeOrArrayElementType(); if (BaseType != EffectiveType) { // Make sure we're comparing apples to apples when comparing index to size uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType); diff --git a/clang/test/SemaCXX/array-bounds.cpp b/clang/test/SemaCXX/array-bounds.cpp index a97f8e312a0..3eb929b93ed 100644 --- a/clang/test/SemaCXX/array-bounds.cpp +++ b/clang/test/SemaCXX/array-bounds.cpp @@ -284,3 +284,12 @@ struct multi_s multi2[4]; // expected-note {{array 'multi2' declared here}} int test_struct_multiarray() { return multi2[4].arr[0]; // expected-warning {{array index 4 is past the end of the array (which contains 4 elements)}} } + +namespace PR39746 { + struct S; + extern S xxx[2]; + class C {}; + + C &f() { return reinterpret_cast<C *>(xxx)[1]; } // no-warning + C &g() { return reinterpret_cast<C *>(xxx)[2]; } // no-warning +} |
