Function codegen

crates/rustc_codegen_nvvm/src/allocator.rs:10–141

adapted from rustc_codegen_llvm

(
    _tcx: TyCtxt<'_>,
    mods: &mut LlvmMod,
    kind: AllocatorKind,
    has_alloc_error_handler: bool,
)

// adapted from rustc_codegen_llvm
pub(crate) unsafe fn codegen(
    _tcx: TyCtxt<'_>,
    mods: &mut LlvmMod,
    kind: AllocatorKind,
    has_alloc_error_handler: bool,
) {
    let llcx = &*mods.llcx;
    let llmod = mods.llmod.as_ref().unwrap();
    let usize = target::usize_ty(llcx);
    let i8 = llvm::LLVMInt8TypeInContext(llcx);
    let i8p = llvm::LLVMPointerType(i8, 0);
    let void = llvm::LLVMVoidTypeInContext(llcx);

    let mut used = Vec::new();

    for method in ALLOCATOR_METHODS {
        let mut args = Vec::with_capacity(method.inputs.len());
        for ty in method.inputs.iter() {
            match *ty {
                AllocatorTy::Layout => {
                    args.push(usize); // size
                    args.push(usize); // align
                }
                AllocatorTy::Ptr => args.push(i8p),
                AllocatorTy::Usize => args.push(usize),

                AllocatorTy::ResultPtr | AllocatorTy::Unit => panic!("invalid allocator arg"),
            }
        }
        let output = match method.output {
            AllocatorTy::ResultPtr => Some(i8p),
            AllocatorTy::Unit => None,

            AllocatorTy::Layout | AllocatorTy::Usize | AllocatorTy::Ptr => {
                panic!("invalid allocator output")
            }
        };

        let ty = llvm::LLVMFunctionType(
            output.unwrap_or(void),
            args.as_ptr(),
            args.len() as c_uint,
            False,
        );
        let name = format!("__rust_{}", method.name);
        let llfn = llvm::LLVMRustGetOrInsertFunction(llmod, name.as_ptr().cast(), name.len(), ty);

        used.push(llfn);
        // nvvm doesnt support uwtable so dont try to generate it

        let callee = kind.fn_name(method.name);
        let callee =
            llvm::LLVMRustGetOrInsertFunction(llmod, callee.as_ptr().cast(), callee.len(), ty);
        llvm::LLVMRustSetVisibility(callee, llvm::Visibility::Hidden);

        let llbb = llvm::LLVMAppendBasicBlockInContext(llcx, llfn, "entry\0".as_ptr().cast());

        let llbuilder = llvm::LLVMCreateBuilderInContext(llcx);