Hi Brian, > Much legacy code has problems with the LP64 model, with I 32 due to truncated > pointers and pointer -> int -> pointer conversions which through away 32 bits > of the pointer. > > Is there anyway to force ILP64 ie 64 bit ints? Clearly for code going forward > one needs to __fic_it|__ but it is a real pain for legacy code of a tool you > only see running once. > > I know that you can force ILP32 on 86_64 but something like -mi64 would be > neat, anyone know an easy way? The C99 <stdint.h> has intptr_t which is big enough to hold a pointer in an int. Change all your int/pointer conflations to use intptr_t for the integer data type. Not quite what you are looking for. What you are asking for is to have a ILP64 on a 64-bit platform. An entirely reasonable request. Especially on a platform where the natural data word size is 64-bit, since C (and hence C++) use Oint¹ to refer to the platform¹s natural data word size. Alas... The most popular 64-bit platforms seem to have gone with a IL32/LLP64 or I32/LP64 as their data type sizes. :-( Changing your compiler to be ILP64 is not a simple matter, since now your code will generate incorrect ABI when interoping with the operating system APIs, the Standard C and C++ libraries, and all DLLs (.so, .dylib, .dll ... whatever your platform uses). You¹d have to fix all the header files. Not fun. Not really feasible, even for the meticulous, pedantic OCD curious -- therein lies the path to madness. Sorry. If you are determined to go down this course, there may be a viable solution. You can build your own operating system (for example, one that is Linux based), which has an ILP64 ABI. (There may be a Linux distro which has already done this.) Sincerely, --Eljay
