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[MIR] Calling extern functions. #30517

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[MIR] Calling extern functions. #30517

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51 changes: 35 additions & 16 deletions src/librustc_trans/trans/mir/block.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -17,8 +17,11 @@ use trans::base;
use trans::build;
use trans::common::{self, Block};
use trans::debuginfo::DebugLoc;
use trans::foreign;
use trans::type_of;

use syntax::abi as synabi;

use super::MirContext;
use super::operand::OperandValue::{FatPtr, Immediate, Ref};

Expand Down Expand Up @@ -112,19 +115,24 @@ impl<'bcx, 'tcx> MirContext<'bcx, 'tcx> {
// Create the callee. This will always be a fn
// ptr and hence a kind of scalar.
let callee = self.trans_operand(bcx, &data.func);
let ret_ty = if let ty::TyBareFn(_, ref f) = callee.ty.sty {
let (abi, ret_ty) = if let ty::TyBareFn(_, ref f) = callee.ty.sty {
let sig = bcx.tcx().erase_late_bound_regions(&f.sig);
let sig = infer::normalize_associated_type(bcx.tcx(), &sig);
sig.output
(f.abi, sig.output)
} else {
panic!("trans_block: expected TyBareFn as callee");
};

// Have we got a 'Rust' function?
let is_rust_fn = abi == synabi::Rust || abi == synabi::RustCall;

// The arguments we'll be passing
let mut llargs = vec![];
let mut llargs = Vec::with_capacity(data.args.len() + 1);
// and their Rust types (formal args only so not outptr)
let mut arg_tys = Vec::with_capacity(data.args.len());

// Does the fn use an outptr? If so, that's the first arg.
if let ty::FnConverging(ret_ty) = ret_ty {
if let (true, ty::FnConverging(ret_ty)) = (is_rust_fn, ret_ty) {
if type_of::return_uses_outptr(bcx.ccx(), ret_ty) {
llargs.push(call_dest.llval);
}
Expand All @@ -133,6 +141,7 @@ impl<'bcx, 'tcx> MirContext<'bcx, 'tcx> {
// Process the rest of the args.
for arg in &data.args {
let arg_op = self.trans_operand(bcx, arg);
arg_tys.push(arg_op.ty);
match arg_op.val {
Ref(llval) | Immediate(llval) => llargs.push(llval),
FatPtr(base, extra) => {
Expand All @@ -148,19 +157,29 @@ impl<'bcx, 'tcx> MirContext<'bcx, 'tcx> {
//self.make_landing_pad(panic_bb);

// Do the actual call.
let (llret, b) = base::invoke(bcx,
callee.immediate(),
&llargs[..],
callee.ty,
DebugLoc::None);
bcx = b;

// Copy the return value into the destination.
if let ty::FnConverging(ret_ty) = ret_ty {
if !type_of::return_uses_outptr(bcx.ccx(), ret_ty) &&
!common::type_is_zero_size(bcx.ccx(), ret_ty) {
base::store_ty(bcx, llret, call_dest.llval, ret_ty);
if is_rust_fn {
let (llret, b) = base::invoke(bcx,
callee.immediate(),
&llargs,
callee.ty,
DebugLoc::None);
bcx = b;

// Copy the return value into the destination.
if let ty::FnConverging(ret_ty) = ret_ty {
if !type_of::return_uses_outptr(bcx.ccx(), ret_ty) &&
!common::type_is_zero_size(bcx.ccx(), ret_ty) {
base::store_ty(bcx, llret, call_dest.llval, ret_ty);
}
}
} else {
bcx = foreign::trans_native_call(bcx,
callee.ty,
callee.immediate(),
call_dest.llval,
&llargs,
arg_tys,
DebugLoc::None);
}

build::Br(bcx, self.llblock(targets.0), DebugLoc::None)
Expand Down
15 changes: 15 additions & 0 deletions src/test/run-pass/mir_trans_calls.rs
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Expand Up @@ -88,6 +88,19 @@ fn test8() -> isize {
Two::two()
}

#[link(name = "c")]
extern {
fn printf(format: *const u8, ...) -> i32;
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hmm, is there something other than printf that we could test here?

I mean, I guess its fine (if a little opaque) to rely on the return value of printf as the basis for the test; but then again, that's relying on them never returning an error code ... seems like there are more direct options here, like strlen, or qsort, (well qsort might be a bit of a stretch).

If you are deliberately trying to test the handling of varargs functions, then maybe go with sscanf? Basically I'm trying to avoid doing IO where the output isn't actually checked for correctness, since that might mask bugs...

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Probably the most obvious VA_ARG function to test is syscall, but it is system-dependent (duh).

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Other functions are fcntl, ioctl, execl{,e,p}. Exec might be a good one I think.

}

#[rustc_mir]
fn native_test() -> i32 {
unsafe {
let format = b"Hello World! There are %d days in a year. Mmmm %.5f\n\0";
printf(format.as_ptr(), 365, 3.14159)
}
}

fn main() {
assert_eq!(test1(1, (2, 3), &[4, 5, 6]), (1, (2, 3), &[4, 5, 6][..]));
assert_eq!(test2(98), 98);
Expand All @@ -97,4 +110,6 @@ fn main() {
assert_eq!(test6(&Foo, 12367), 12367);
assert_eq!(test7(), 1);
assert_eq!(test8(), 2);

assert_eq!(native_test(), 56);
}