On Sat, Mar 30, 2024 at 02:58:41AM +0000, bugzi...@dpdk.org wrote: > https://bugs.dpdk.org/show_bug.cgi?id=1409 > > Bug ID: 1409 > Summary: arparse library assumes enum are 64 bit > Product: DPDK > Version: 24.03 > Hardware: All > OS: All > Status: UNCONFIRMED > Severity: normal > Priority: Normal > Component: core > Assignee: dev@dpdk.org > Reporter: step...@networkplumber.org > Target Milestone: --- > > MSVC correctly flags that this line in rte_argparse.h is incorrect: > RTE_ARGPARSE_ARG_RESERVED_FIELD = RTE_GENMASK64(63, 48), > > The problem is that enum values are just an alias for int, and it can be 32 > bits. > > Taken from the current C Standard (C99): > http://www.open std.org/JTC1/SC22/WG14/www/docs/n1256.pdf > > 6.7.2.2 Enumeration specifiers > [...] > Constraints > The expression that defines the value of an enumeration constant shall be an > integer constant expression that has a value representable as an int. > [...] > Each enumerated type shall be compatible with char, a signed integer type, or > an unsigned integer type. The choice of type is implementation-defined, but > shall be capable of representing the values of all the members of the > enumeration. > > Since rte_argparse only uses 10 bits now. The suggested fix here is to: > 1. Assume 32 bits > 2. Get rid of the reserved field - reserved fields are bad idea >
as some additional information i was aware of this issue and had already discussing it internally with the visual studio engineers. we reviewed relevant parts of C11 standard we believe there are 2 points of interest. the C11 standard does appear to direct the implementation to select an integer wide enough to hold the 64-bit enum value but it is only reasonable to do so when the target has a native 64-bit type. i.e. if your target has no 64-bit integer than the size of the above constant expression will be truncated. the MSVC compiler requires an extra command line argument to provide standard C conformant behavior (/Zc:enumTypes). when used with a C++ TU MSVC does select a 64-bit type for the prescribed constant expression but does not correctly select a 64-bit type with a C TU (this matters if we are exposing this enum type in a public header consumed by C++) i'm in the process of requesting that /Zc:enumTypes be brought into alignment with how it functions with C++ TU. * /Zc:enumTypes should result in "the same" type being selected for C or C++ TU, whatever that type may be. * /Zc:enumTypes in a C TU should select a 64-bit integer type for the above example value when the target supports 64-bit integer natively. as the current released compiler obviously does not conform to the above we may apply a conditionally compiled workaround that declares a 64-bit integer with an identifier matching the name of the un-scoped enum value. ty > -- > You are receiving this mail because: > You are the assignee for the bug.
