Length parameters for the C API should be 'size_t', not 'unsigned'.

[llvmbot]

Bugzilla Link	9242
Resolution	WONTFIX
Resolved on	May 01, 2020 22:10
Version	2.8
OS	All
Reporter	LLVM Bugzilla Contributor
CC	@ekatz

Extended Description

A lot of the C wrapper functions take a pointer and a length when expecting a list of things. For instance, the signature of LLVMBuildCall:

... LLVMBuildCall(..., LLVMValueRef* Args, unsigned NumArgs,...)

Usually, unsigned i declares i as 32 bit unsigned integer. On 32 bit architectures, this can adequately index a pointer and all is well. On 64 bit architectures, however, a 64 bit unsigned integer is required to do this. The size_t type (in cstdint) does this job. In the above example, NumArgs should be declared as size_t NumArgs.

Incidentally, this bugs me as I'm using the C API from D. D arrays have a pointer and a length -- the length is declared as size_t. when using the above, I can create a D array of LLVMValueRefs and then pass it like

LLVMBuildCall(..., args.ptr, args.length,...)

Except if I'm building for 64 bit, I have to explicitly cast the length to uint to call LLVM.

[ekatz]

There is a patch I uploaded for review in https://reviews.llvm.org/D78746.
But it will break the ABI, which complicates the solution too much for me (or seems to be anyone else right now) to pursue.

I am closing this bug as it is almost a decade old, and there seems to be no other interest in this change.

Feel free to reopen this issue, if the need rises.