From 13234ae40db3d89fcd05a3b59f4e3e25133c4976 Mon Sep 17 00:00:00 2001 From: Hubert Tong Date: Mon, 8 Jun 2015 21:59:59 +0000 Subject: Consider unsigned long for non-u/U decimal literals (C90/C++03) Summary: This modifies Clang to reflect that under pre-C99 ISO C, decimal constants may have type `unsigned long` even if they do not contain `u` or `U` in their suffix (C90 subclause 6.1.3.2 paragraph 5). The same is done for C++ without C++11 which--because of undefined behaviour--allows for behaviour compatible with ISO C90 in the case of an unsuffixed decimal literal and is otherwise identical to C90 in its treatment of integer literals (C++03 subclause 2.13.1 [lex.icon] paragraph 2). Messages are added to the `c99-compat` and `c++11-compat` groups to warn on such literals, since they behave differently under the newer standards. Fixes PR 16678. Test Plan: A new test file is added to exercise both pre-C99/C++11 and C99/C++11-up on decimal literals with no suffix or suffixes `l`/`L` for both 32-bit and 64-bit `long`. In the file, 2^31 (being `INT_MAX+1`) is tested for the expected type using `__typeof__` and multiple declarations of the same entity. 2^63 is similarly tested when it is within the range of `unsigned long`. Preprocessor arithmetic tests are added to ensure consistency given that Clang (like GCC) uses greater than 32 bits for preprocessor arithmetic even when `long` and `unsigned long` is 32 bits and a pre-C99/C++11 mode is in effect. Tests added: test/Sema/PR16678.c Reviewers: fraggamuffin, rsmith Reviewed By: rsmith Subscribers: cfe-commits Differential Revision: http://reviews.llvm.org/D9794 llvm-svn: 239356 --- clang/lib/Sema/SemaExpr.cpp | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'clang/lib/Sema/SemaExpr.cpp') diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp index dfb17f4bbc3..b0bc231e7e6 100644 --- a/clang/lib/Sema/SemaExpr.cpp +++ b/clang/lib/Sema/SemaExpr.cpp @@ -3425,6 +3425,22 @@ ExprResult Sema::ActOnNumericConstant(const Token &Tok, Scope *UDLScope) { Ty = Context.LongTy; else if (AllowUnsigned) Ty = Context.UnsignedLongTy; + // Check according to the rules of C90 6.1.3.2p5. C++03 [lex.icon]p2 + // is compatible. + else if (!getLangOpts().C99 && !getLangOpts().CPlusPlus11) { + const unsigned LongLongSize = + Context.getTargetInfo().getLongLongWidth(); + Diag(Tok.getLocation(), + getLangOpts().CPlusPlus + ? Literal.isLong + ? diag::warn_old_implicitly_unsigned_long_cxx + : /*C++98 UB*/ diag:: + ext_old_implicitly_unsigned_long_cxx + : diag::warn_old_implicitly_unsigned_long) + << (LongLongSize > LongSize ? /*will have type 'long long'*/ 0 + : /*will be ill-formed*/ 1); + Ty = Context.UnsignedLongTy; + } Width = LongSize; } } -- cgit v1.2.3