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auto merge of #14439 : thestinger/rust/nonnull, r=luqmana

This commit is contained in:
bors 2014-05-26 01:51:25 -07:00
parent ba77c60270 22ab5303ff
commit 6fad19e16b
1 changed files with 10 additions and 14 deletions
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24
src/librustc/middle/trans/base.rs
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@ -1780,16 +1780,20 @@ pub fn get_fn_llvm_attributes(ccx: &CrateContext, fn_ty: ty::t) -> Vec<(uint, u6
for (idx, &t) in fn_sig.inputs.iter().enumerate().map(|(i, v)| (i + first_arg_offset, v)) {
match ty::get(t).sty {
// this needs to be first to prevent fat pointers from falling through
_ if !type_is_immediate(ccx, t) => {
// For non-immediate arguments the callee gets its own copy of
// the value on the stack, so there are no aliases. It's also
// program-invisible so can't possibly capture
attrs.push((idx, lib::llvm::NoAliasAttribute as u64));
attrs.push((idx, lib::llvm::NoCaptureAttribute as u64));
attrs.push((idx, lib::llvm::NonNullAttribute as u64));
}
// `~` pointer parameters never alias because ownership is transferred
ty::ty_uniq(_) => {
attrs.push((idx, lib::llvm::NoAliasAttribute as u64));
attrs.push((idx, lib::llvm::NonNullAttribute as u64));
}
// These are not really pointers but pairs, (pointer, len)
ty::ty_rptr(_, ty::mt { ty: it, .. }) |
ty::ty_rptr(_, ty::mt { ty: it, .. }) if match ty::get(it).sty {
ty::ty_str | ty::ty_vec(..) => true, _ => false
} => {}
// `&mut` pointer parameters never alias other parameters, or mutable global data
ty::ty_rptr(b, mt) if mt.mutbl == ast::MutMutable => {
attrs.push((idx, lib::llvm::NoAliasAttribute as u64));
@ -1811,15 +1815,7 @@ pub fn get_fn_llvm_attributes(ccx: &CrateContext, fn_ty: ty::t) -> Vec<(uint, u6
ty::ty_rptr(_, _) => {
attrs.push((idx, lib::llvm::NonNullAttribute as u64));
}
_ => {
// For non-immediate arguments the callee gets its own copy of
// the value on the stack, so there are no aliases. It's also
// program-invisible so can't possibly capture
if !type_is_immediate(ccx, t) {
attrs.push((idx, lib::llvm::NoAliasAttribute as u64));
attrs.push((idx, lib::llvm::NoCaptureAttribute as u64));
}
}
_ => ()
}
}