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fuchsia / third_party / rust / 1.7.0 / . / src / librustc_trans / trans / base.rs
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// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! Translate the completed AST to the LLVM IR.
//!
//! Some functions here, such as trans_block and trans_expr, return a value --
//! the result of the translation to LLVM -- while others, such as trans_fn,
//! trans_impl, and trans_item, are called only for the side effect of adding a
//! particular definition to the LLVM IR output we're producing.
//!
//! Hopefully useful general knowledge about trans:
//!
//! * There's no way to find out the Ty type of a ValueRef. Doing so
//! would be "trying to get the eggs out of an omelette" (credit:
//! pcwalton). You can, instead, find out its TypeRef by calling val_ty,
//! but one TypeRef corresponds to many `Ty`s; for instance, tup(int, int,
//! int) and rec(x=int, y=int, z=int) will have the same TypeRef.
#![allow(non_camel_case_types)]
pub use self::ValueOrigin::*;
use super::CrateTranslation;
use super::ModuleTranslation;
use back::link::mangle_exported_name;
use back::{link, abi};
use lint;
use llvm::{BasicBlockRef, Linkage, ValueRef, Vector, get_param};
use llvm;
use middle::cfg;
use middle::cstore::CrateStore;
use middle::def_id::DefId;
use middle::infer;
use middle::lang_items::{LangItem, ExchangeMallocFnLangItem, StartFnLangItem};
use middle::weak_lang_items;
use middle::pat_util::simple_name;
use middle::subst::Substs;
use middle::ty::{self, Ty, TypeFoldable};
use rustc::dep_graph::DepNode;
use rustc::front::map as hir_map;
use rustc::util::common::time;
use rustc_mir::mir_map::MirMap;
use session::config::{self, NoDebugInfo, FullDebugInfo};
use session::Session;
use trans::_match;
use trans::adt;
use trans::assert_dep_graph;
use trans::attributes;
use trans::build::*;
use trans::builder::{Builder, noname};
use trans::callee;
use trans::cleanup::{self, CleanupMethods, DropHint};
use trans::closure;
use trans::common::{Block, C_bool, C_bytes_in_context, C_i32, C_int, C_uint, C_integral};
use trans::common::{C_null, C_struct_in_context, C_u64, C_u8, C_undef};
use trans::common::{CrateContext, DropFlagHintsMap, Field, FunctionContext};
use trans::common::{Result, NodeIdAndSpan, VariantInfo};
use trans::common::{node_id_type, return_type_is_void};
use trans::common::{type_is_immediate, type_is_zero_size, val_ty};
use trans::common;
use trans::consts;
use trans::context::SharedCrateContext;
use trans::controlflow;
use trans::datum;
use trans::debuginfo::{self, DebugLoc, ToDebugLoc};
use trans::declare;
use trans::expr;
use trans::foreign;
use trans::glue;
use trans::intrinsic;
use trans::machine;
use trans::machine::{llsize_of, llsize_of_real};
use trans::meth;
use trans::mir;
use trans::monomorphize;
use trans::tvec;
use trans::type_::Type;
use trans::type_of;
use trans::type_of::*;
use trans::value::Value;
use trans::Disr;
use util::common::indenter;
use util::sha2::Sha256;
use util::nodemap::{NodeMap, NodeSet};
use arena::TypedArena;
use libc::c_uint;
use std::ffi::{CStr, CString};
use std::cell::{Cell, RefCell};
use std::collections::{HashMap, HashSet};
use std::str;
use std::{i8, i16, i32, i64};
use syntax::abi::{Rust, RustCall, RustIntrinsic, PlatformIntrinsic, Abi};
use syntax::codemap::Span;
use syntax::parse::token::InternedString;
use syntax::attr::AttrMetaMethods;
use syntax::attr;
use rustc_front;
use rustc_front::intravisit::{self, Visitor};
use rustc_front::hir;
use syntax::ast;
thread_local! {
static TASK_LOCAL_INSN_KEY: RefCell<Option<Vec<&'static str>>> = {
RefCell::new(None)
}
}
pub fn with_insn_ctxt<F>(blk: F)
where F: FnOnce(&[&'static str])
{
TASK_LOCAL_INSN_KEY.with(move |slot| {
slot.borrow().as_ref().map(move |s| blk(s));
})
}
pub fn init_insn_ctxt() {
TASK_LOCAL_INSN_KEY.with(|slot| {
*slot.borrow_mut() = Some(Vec::new());
});
}
pub struct _InsnCtxt {
_cannot_construct_outside_of_this_module: (),
}
impl Drop for _InsnCtxt {
fn drop(&mut self) {
TASK_LOCAL_INSN_KEY.with(|slot| {
match slot.borrow_mut().as_mut() {
Some(ctx) => {
ctx.pop();
}
None => {}
}
})
}
}
pub fn push_ctxt(s: &'static str) -> _InsnCtxt {
debug!("new InsnCtxt: {}", s);
TASK_LOCAL_INSN_KEY.with(|slot| {
match slot.borrow_mut().as_mut() {
Some(ctx) => ctx.push(s),
None => {}
}
});
_InsnCtxt {
_cannot_construct_outside_of_this_module: (),
}
}
pub struct StatRecorder<'a, 'tcx: 'a> {
ccx: &'a CrateContext<'a, 'tcx>,
name: Option<String>,
istart: usize,
}
impl<'a, 'tcx> StatRecorder<'a, 'tcx> {
pub fn new(ccx: &'a CrateContext<'a, 'tcx>, name: String) -> StatRecorder<'a, 'tcx> {
let istart = ccx.stats().n_llvm_insns.get();
StatRecorder {
ccx: ccx,
name: Some(name),
istart: istart,
}
}
}
impl<'a, 'tcx> Drop for StatRecorder<'a, 'tcx> {
fn drop(&mut self) {
if self.ccx.sess().trans_stats() {
let iend = self.ccx.stats().n_llvm_insns.get();
self.ccx
.stats()
.fn_stats
.borrow_mut()
.push((self.name.take().unwrap(), iend - self.istart));
self.ccx.stats().n_fns.set(self.ccx.stats().n_fns.get() + 1);
// Reset LLVM insn count to avoid compound costs.
self.ccx.stats().n_llvm_insns.set(self.istart);
}
}
}
fn get_extern_rust_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
fn_ty: Ty<'tcx>,
name: &str,
did: DefId)
-> ValueRef {
match ccx.externs().borrow().get(name) {
Some(n) => return *n,
None => (),
}
let f = declare::declare_rust_fn(ccx, name, fn_ty);
let attrs = ccx.sess().cstore.item_attrs(did);
attributes::from_fn_attrs(ccx, &attrs[..], f);
ccx.externs().borrow_mut().insert(name.to_string(), f);
f
}
pub fn self_type_for_closure<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
closure_id: DefId,
fn_ty: Ty<'tcx>)
-> Ty<'tcx> {
let closure_kind = ccx.tcx().closure_kind(closure_id);
match closure_kind {
ty::FnClosureKind => {
ccx.tcx().mk_imm_ref(ccx.tcx().mk_region(ty::ReStatic), fn_ty)
}
ty::FnMutClosureKind => {
ccx.tcx().mk_mut_ref(ccx.tcx().mk_region(ty::ReStatic), fn_ty)
}
ty::FnOnceClosureKind => fn_ty,
}
}
pub fn kind_for_closure(ccx: &CrateContext, closure_id: DefId) -> ty::ClosureKind {
*ccx.tcx().tables.borrow().closure_kinds.get(&closure_id).unwrap()
}
pub fn get_extern_const<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
did: DefId,
t: Ty<'tcx>)
-> ValueRef {
let name = ccx.sess().cstore.item_symbol(did);
let ty = type_of(ccx, t);
match ccx.externs().borrow_mut().get(&name) {
Some(n) => return *n,
None => (),
}
// FIXME(nagisa): perhaps the map of externs could be offloaded to llvm somehow?
// FIXME(nagisa): investigate whether it can be changed into define_global
let c = declare::declare_global(ccx, &name[..], ty);
// Thread-local statics in some other crate need to *always* be linked
// against in a thread-local fashion, so we need to be sure to apply the
// thread-local attribute locally if it was present remotely. If we
// don't do this then linker errors can be generated where the linker
// complains that one object files has a thread local version of the
// symbol and another one doesn't.
for attr in ccx.tcx().get_attrs(did).iter() {
if attr.check_name("thread_local") {
llvm::set_thread_local(c, true);
}
}
if ccx.use_dll_storage_attrs() {
llvm::SetDLLStorageClass(c, llvm::DLLImportStorageClass);
}
ccx.externs().borrow_mut().insert(name.to_string(), c);
return c;
}
fn require_alloc_fn<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, info_ty: Ty<'tcx>, it: LangItem) -> DefId {
match bcx.tcx().lang_items.require(it) {
Ok(id) => id,
Err(s) => {
bcx.sess().fatal(&format!("allocation of `{}` {}", info_ty, s));
}
}
}
// The following malloc_raw_dyn* functions allocate a box to contain
// a given type, but with a potentially dynamic size.
pub fn malloc_raw_dyn<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
llty_ptr: Type,
info_ty: Ty<'tcx>,
size: ValueRef,
align: ValueRef,
debug_loc: DebugLoc)
-> Result<'blk, 'tcx> {
let _icx = push_ctxt("malloc_raw_exchange");
// Allocate space:
let r = callee::trans_lang_call(bcx,
require_alloc_fn(bcx, info_ty, ExchangeMallocFnLangItem),
&[size, align],
None,
debug_loc);
Result::new(r.bcx, PointerCast(r.bcx, r.val, llty_ptr))
}
pub fn bin_op_to_icmp_predicate(ccx: &CrateContext,
op: hir::BinOp_,
signed: bool)
-> llvm::IntPredicate {
match op {
hir::BiEq => llvm::IntEQ,
hir::BiNe => llvm::IntNE,
hir::BiLt => if signed { llvm::IntSLT } else { llvm::IntULT },
hir::BiLe => if signed { llvm::IntSLE } else { llvm::IntULE },
hir::BiGt => if signed { llvm::IntSGT } else { llvm::IntUGT },
hir::BiGe => if signed { llvm::IntSGE } else { llvm::IntUGE },
op => {
ccx.sess()
.bug(&format!("comparison_op_to_icmp_predicate: expected comparison operator, \
found {:?}",
op));
}
}
}
pub fn bin_op_to_fcmp_predicate(ccx: &CrateContext, op: hir::BinOp_) -> llvm::RealPredicate {
match op {
hir::BiEq => llvm::RealOEQ,
hir::BiNe => llvm::RealUNE,
hir::BiLt => llvm::RealOLT,
hir::BiLe => llvm::RealOLE,
hir::BiGt => llvm::RealOGT,
hir::BiGe => llvm::RealOGE,
op => {
ccx.sess()
.bug(&format!("comparison_op_to_fcmp_predicate: expected comparison operator, \
found {:?}",
op));
}
}
}
pub fn compare_fat_ptrs<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
lhs_addr: ValueRef,
lhs_extra: ValueRef,
rhs_addr: ValueRef,
rhs_extra: ValueRef,
_t: Ty<'tcx>,
op: hir::BinOp_,
debug_loc: DebugLoc)
-> ValueRef {
match op {
hir::BiEq => {
let addr_eq = ICmp(bcx, llvm::IntEQ, lhs_addr, rhs_addr, debug_loc);
let extra_eq = ICmp(bcx, llvm::IntEQ, lhs_extra, rhs_extra, debug_loc);
And(bcx, addr_eq, extra_eq, debug_loc)
}
hir::BiNe => {
let addr_eq = ICmp(bcx, llvm::IntNE, lhs_addr, rhs_addr, debug_loc);
let extra_eq = ICmp(bcx, llvm::IntNE, lhs_extra, rhs_extra, debug_loc);
Or(bcx, addr_eq, extra_eq, debug_loc)
}
hir::BiLe | hir::BiLt | hir::BiGe | hir::BiGt => {
// a OP b ~ a.0 STRICT(OP) b.0 | (a.0 == b.0 && a.1 OP a.1)
let (op, strict_op) = match op {
hir::BiLt => (llvm::IntULT, llvm::IntULT),
hir::BiLe => (llvm::IntULE, llvm::IntULT),
hir::BiGt => (llvm::IntUGT, llvm::IntUGT),
hir::BiGe => (llvm::IntUGE, llvm::IntUGT),
_ => unreachable!(),
};
let addr_eq = ICmp(bcx, llvm::IntEQ, lhs_addr, rhs_addr, debug_loc);
let extra_op = ICmp(bcx, op, lhs_extra, rhs_extra, debug_loc);
let addr_eq_extra_op = And(bcx, addr_eq, extra_op, debug_loc);
let addr_strict = ICmp(bcx, strict_op, lhs_addr, rhs_addr, debug_loc);
Or(bcx, addr_strict, addr_eq_extra_op, debug_loc)
}
_ => {
bcx.tcx().sess.bug("unexpected fat ptr binop");
}
}
}
pub fn compare_scalar_types<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
lhs: ValueRef,
rhs: ValueRef,
t: Ty<'tcx>,
op: hir::BinOp_,
debug_loc: DebugLoc)
-> ValueRef {
match t.sty {
ty::TyTuple(ref tys) if tys.is_empty() => {
// We don't need to do actual comparisons for nil.
// () == () holds but () < () does not.
match op {
hir::BiEq | hir::BiLe | hir::BiGe => return C_bool(bcx.ccx(), true),
hir::BiNe | hir::BiLt | hir::BiGt => return C_bool(bcx.ccx(), false),
// refinements would be nice
_ => bcx.sess().bug("compare_scalar_types: must be a comparison operator"),
}
}
ty::TyBareFn(..) | ty::TyBool | ty::TyUint(_) | ty::TyChar => {
ICmp(bcx,
bin_op_to_icmp_predicate(bcx.ccx(), op, false),
lhs,
rhs,
debug_loc)
}
ty::TyRawPtr(mt) if common::type_is_sized(bcx.tcx(), mt.ty) => {
ICmp(bcx,
bin_op_to_icmp_predicate(bcx.ccx(), op, false),
lhs,
rhs,
debug_loc)
}
ty::TyRawPtr(_) => {
let lhs_addr = Load(bcx, GEPi(bcx, lhs, &[0, abi::FAT_PTR_ADDR]));
let lhs_extra = Load(bcx, GEPi(bcx, lhs, &[0, abi::FAT_PTR_EXTRA]));
let rhs_addr = Load(bcx, GEPi(bcx, rhs, &[0, abi::FAT_PTR_ADDR]));
let rhs_extra = Load(bcx, GEPi(bcx, rhs, &[0, abi::FAT_PTR_EXTRA]));
compare_fat_ptrs(bcx,
lhs_addr,
lhs_extra,
rhs_addr,
rhs_extra,
t,
op,
debug_loc)
}
ty::TyInt(_) => {
ICmp(bcx,
bin_op_to_icmp_predicate(bcx.ccx(), op, true),
lhs,
rhs,
debug_loc)
}
ty::TyFloat(_) => {
FCmp(bcx,
bin_op_to_fcmp_predicate(bcx.ccx(), op),
lhs,
rhs,
debug_loc)
}
// Should never get here, because t is scalar.
_ => bcx.sess().bug("non-scalar type passed to compare_scalar_types"),
}
}
pub fn compare_simd_types<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
lhs: ValueRef,
rhs: ValueRef,
t: Ty<'tcx>,
ret_ty: Type,
op: hir::BinOp_,
debug_loc: DebugLoc)
-> ValueRef {
let signed = match t.sty {
ty::TyFloat(_) => {
let cmp = bin_op_to_fcmp_predicate(bcx.ccx(), op);
return SExt(bcx, FCmp(bcx, cmp, lhs, rhs, debug_loc), ret_ty);
},
ty::TyUint(_) => false,
ty::TyInt(_) => true,
_ => bcx.sess().bug("compare_simd_types: invalid SIMD type"),
};
let cmp = bin_op_to_icmp_predicate(bcx.ccx(), op, signed);
// LLVM outputs an `< size x i1 >`, so we need to perform a sign extension
// to get the correctly sized type. This will compile to a single instruction
// once the IR is converted to assembly if the SIMD instruction is supported
// by the target architecture.
SExt(bcx, ICmp(bcx, cmp, lhs, rhs, debug_loc), ret_ty)
}
// Iterates through the elements of a structural type.
pub fn iter_structural_ty<'blk, 'tcx, F>(cx: Block<'blk, 'tcx>,
av: ValueRef,
t: Ty<'tcx>,
mut f: F)
-> Block<'blk, 'tcx>
where F: FnMut(Block<'blk, 'tcx>, ValueRef, Ty<'tcx>) -> Block<'blk, 'tcx>
{
let _icx = push_ctxt("iter_structural_ty");
fn iter_variant<'blk, 'tcx, F>(cx: Block<'blk, 'tcx>,
repr: &adt::Repr<'tcx>,
av: adt::MaybeSizedValue,
variant: ty::VariantDef<'tcx>,
substs: &Substs<'tcx>,
f: &mut F)
-> Block<'blk, 'tcx>
where F: FnMut(Block<'blk, 'tcx>, ValueRef, Ty<'tcx>) -> Block<'blk, 'tcx>
{
let _icx = push_ctxt("iter_variant");
let tcx = cx.tcx();
let mut cx = cx;
for (i, field) in variant.fields.iter().enumerate() {
let arg = monomorphize::field_ty(tcx, substs, field);
cx = f(cx,
adt::trans_field_ptr(cx, repr, av, Disr::from(variant.disr_val), i),
arg);
}
return cx;
}
let value = if common::type_is_sized(cx.tcx(), t) {
adt::MaybeSizedValue::sized(av)
} else {
let data = Load(cx, expr::get_dataptr(cx, av));
let info = Load(cx, expr::get_meta(cx, av));
adt::MaybeSizedValue::unsized_(data, info)
};
let mut cx = cx;
match t.sty {
ty::TyStruct(..) => {
let repr = adt::represent_type(cx.ccx(), t);
let VariantInfo { fields, discr } = VariantInfo::from_ty(cx.tcx(), t, None);
for (i, &Field(_, field_ty)) in fields.iter().enumerate() {
let llfld_a = adt::trans_field_ptr(cx, &*repr, value, Disr::from(discr), i);
let val = if common::type_is_sized(cx.tcx(), field_ty) {
llfld_a
} else {
let scratch = datum::rvalue_scratch_datum(cx, field_ty, "__fat_ptr_iter");
Store(cx, llfld_a, expr::get_dataptr(cx, scratch.val));
Store(cx, value.meta, expr::get_meta(cx, scratch.val));
scratch.val
};
cx = f(cx, val, field_ty);
}
}
ty::TyClosure(_, ref substs) => {
let repr = adt::represent_type(cx.ccx(), t);
for (i, upvar_ty) in substs.upvar_tys.iter().enumerate() {
let llupvar = adt::trans_field_ptr(cx, &*repr, value, Disr(0), i);
cx = f(cx, llupvar, upvar_ty);
}
}
ty::TyArray(_, n) => {
let (base, len) = tvec::get_fixed_base_and_len(cx, value.value, n);
let unit_ty = t.sequence_element_type(cx.tcx());
cx = tvec::iter_vec_raw(cx, base, unit_ty, len, f);
}
ty::TySlice(_) | ty::TyStr => {
let unit_ty = t.sequence_element_type(cx.tcx());
cx = tvec::iter_vec_raw(cx, value.value, unit_ty, value.meta, f);
}
ty::TyTuple(ref args) => {
let repr = adt::represent_type(cx.ccx(), t);
for (i, arg) in args.iter().enumerate() {
let llfld_a = adt::trans_field_ptr(cx, &*repr, value, Disr(0), i);
cx = f(cx, llfld_a, *arg);
}
}
ty::TyEnum(en, substs) => {
let fcx = cx.fcx;
let ccx = fcx.ccx;
let repr = adt::represent_type(ccx, t);
let n_variants = en.variants.len();
// NB: we must hit the discriminant first so that structural
// comparison know not to proceed when the discriminants differ.
match adt::trans_switch(cx, &*repr, av) {
(_match::Single, None) => {
if n_variants != 0 {
assert!(n_variants == 1);
cx = iter_variant(cx, &*repr, adt::MaybeSizedValue::sized(av),
&en.variants[0], substs, &mut f);
}
}
(_match::Switch, Some(lldiscrim_a)) => {
cx = f(cx, lldiscrim_a, cx.tcx().types.isize);
// Create a fall-through basic block for the "else" case of
// the switch instruction we're about to generate. Note that
// we do **not** use an Unreachable instruction here, even
// though most of the time this basic block will never be hit.
//
// When an enum is dropped it's contents are currently
// overwritten to DTOR_DONE, which means the discriminant
// could have changed value to something not within the actual
// range of the discriminant. Currently this function is only
// used for drop glue so in this case we just return quickly
// from the outer function, and any other use case will only
// call this for an already-valid enum in which case the `ret
// void` will never be hit.
let ret_void_cx = fcx.new_temp_block("enum-iter-ret-void");
RetVoid(ret_void_cx, DebugLoc::None);
let llswitch = Switch(cx, lldiscrim_a, ret_void_cx.llbb, n_variants);
let next_cx = fcx.new_temp_block("enum-iter-next");
for variant in &en.variants {
let variant_cx = fcx.new_temp_block(&format!("enum-iter-variant-{}",
&variant.disr_val
.to_string()));
let case_val = adt::trans_case(cx, &*repr, Disr::from(variant.disr_val));
AddCase(llswitch, case_val, variant_cx.llbb);
let variant_cx = iter_variant(variant_cx,
&*repr,
value,
variant,
substs,
&mut f);
Br(variant_cx, next_cx.llbb, DebugLoc::None);
}
cx = next_cx;
}
_ => ccx.sess().unimpl("value from adt::trans_switch in iter_structural_ty"),
}
}
_ => {
cx.sess().unimpl(&format!("type in iter_structural_ty: {}", t))
}
}
return cx;
}
/// Retrieve the information we are losing (making dynamic) in an unsizing
/// adjustment.
///
/// The `old_info` argument is a bit funny. It is intended for use
/// in an upcast, where the new vtable for an object will be drived
/// from the old one.
pub fn unsized_info<'ccx, 'tcx>(ccx: &CrateContext<'ccx, 'tcx>,
source: Ty<'tcx>,
target: Ty<'tcx>,
old_info: Option<ValueRef>,
param_substs: &'tcx Substs<'tcx>)
-> ValueRef {
let (source, target) = ccx.tcx().struct_lockstep_tails(source, target);
match (&source.sty, &target.sty) {
(&ty::TyArray(_, len), &ty::TySlice(_)) => C_uint(ccx, len),
(&ty::TyTrait(_), &ty::TyTrait(_)) => {
// For now, upcasts are limited to changes in marker
// traits, and hence never actually require an actual
// change to the vtable.
old_info.expect("unsized_info: missing old info for trait upcast")
}
(_, &ty::TyTrait(box ty::TraitTy { ref principal, .. })) => {
// Note that we preserve binding levels here:
let substs = principal.0.substs.with_self_ty(source).erase_regions();
let substs = ccx.tcx().mk_substs(substs);
let trait_ref = ty::Binder(ty::TraitRef {
def_id: principal.def_id(),
substs: substs,
});
consts::ptrcast(meth::get_vtable(ccx, trait_ref, param_substs),
Type::vtable_ptr(ccx))
}
_ => ccx.sess().bug(&format!("unsized_info: invalid unsizing {:?} -> {:?}",
source,
target)),
}
}
/// Coerce `src` to `dst_ty`. `src_ty` must be a thin pointer.
pub fn unsize_thin_ptr<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
src: ValueRef,
src_ty: Ty<'tcx>,
dst_ty: Ty<'tcx>)
-> (ValueRef, ValueRef) {
debug!("unsize_thin_ptr: {:?} => {:?}", src_ty, dst_ty);
match (&src_ty.sty, &dst_ty.sty) {
(&ty::TyBox(a), &ty::TyBox(b)) |
(&ty::TyRef(_, ty::TypeAndMut { ty: a, .. }),
&ty::TyRef(_, ty::TypeAndMut { ty: b, .. })) |
(&ty::TyRef(_, ty::TypeAndMut { ty: a, .. }),
&ty::TyRawPtr(ty::TypeAndMut { ty: b, .. })) |
(&ty::TyRawPtr(ty::TypeAndMut { ty: a, .. }),
&ty::TyRawPtr(ty::TypeAndMut { ty: b, .. })) => {
assert!(common::type_is_sized(bcx.tcx(), a));
let ptr_ty = type_of::in_memory_type_of(bcx.ccx(), b).ptr_to();
(PointerCast(bcx, src, ptr_ty),
unsized_info(bcx.ccx(), a, b, None, bcx.fcx.param_substs))
}
_ => bcx.sess().bug("unsize_thin_ptr: called on bad types"),
}
}
/// Coerce `src`, which is a reference to a value of type `src_ty`,
/// to a value of type `dst_ty` and store the result in `dst`
pub fn coerce_unsized_into<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
src: ValueRef,
src_ty: Ty<'tcx>,
dst: ValueRef,
dst_ty: Ty<'tcx>) {
match (&src_ty.sty, &dst_ty.sty) {
(&ty::TyBox(..), &ty::TyBox(..)) |
(&ty::TyRef(..), &ty::TyRef(..)) |
(&ty::TyRef(..), &ty::TyRawPtr(..)) |
(&ty::TyRawPtr(..), &ty::TyRawPtr(..)) => {
let (base, info) = if common::type_is_fat_ptr(bcx.tcx(), src_ty) {
// fat-ptr to fat-ptr unsize preserves the vtable
load_fat_ptr(bcx, src, src_ty)
} else {
let base = load_ty(bcx, src, src_ty);
unsize_thin_ptr(bcx, base, src_ty, dst_ty)
};
store_fat_ptr(bcx, base, info, dst, dst_ty);
}
// This can be extended to enums and tuples in the future.
// (&ty::TyEnum(def_id_a, _), &ty::TyEnum(def_id_b, _)) |
(&ty::TyStruct(def_a, _), &ty::TyStruct(def_b, _)) => {
assert_eq!(def_a, def_b);
let src_repr = adt::represent_type(bcx.ccx(), src_ty);
let src_fields = match &*src_repr {
&adt::Repr::Univariant(ref s, _) => &s.fields,
_ => bcx.sess().bug("struct has non-univariant repr"),
};
let dst_repr = adt::represent_type(bcx.ccx(), dst_ty);
let dst_fields = match &*dst_repr {
&adt::Repr::Univariant(ref s, _) => &s.fields,
_ => bcx.sess().bug("struct has non-univariant repr"),
};
let src = adt::MaybeSizedValue::sized(src);
let dst = adt::MaybeSizedValue::sized(dst);
let iter = src_fields.iter().zip(dst_fields).enumerate();
for (i, (src_fty, dst_fty)) in iter {
if type_is_zero_size(bcx.ccx(), dst_fty) {
continue;
}
let src_f = adt::trans_field_ptr(bcx, &src_repr, src, Disr(0), i);
let dst_f = adt::trans_field_ptr(bcx, &dst_repr, dst, Disr(0), i);
if src_fty == dst_fty {
memcpy_ty(bcx, dst_f, src_f, src_fty);
} else {
coerce_unsized_into(bcx, src_f, src_fty, dst_f, dst_fty);
}
}
}
_ => bcx.sess().bug(&format!("coerce_unsized_into: invalid coercion {:?} -> {:?}",
src_ty,
dst_ty)),
}
}
pub fn cast_shift_expr_rhs(cx: Block, op: hir::BinOp_, lhs: ValueRef, rhs: ValueRef) -> ValueRef {
cast_shift_rhs(op, lhs, rhs, |a, b| Trunc(cx, a, b), |a, b| ZExt(cx, a, b))
}
pub fn cast_shift_const_rhs(op: hir::BinOp_, lhs: ValueRef, rhs: ValueRef) -> ValueRef {
cast_shift_rhs(op,
lhs,
rhs,
|a, b| unsafe { llvm::LLVMConstTrunc(a, b.to_ref()) },
|a, b| unsafe { llvm::LLVMConstZExt(a, b.to_ref()) })
}
fn cast_shift_rhs<F, G>(op: hir::BinOp_,
lhs: ValueRef,
rhs: ValueRef,
trunc: F,
zext: G)
-> ValueRef
where F: FnOnce(ValueRef, Type) -> ValueRef,
G: FnOnce(ValueRef, Type) -> ValueRef
{
// Shifts may have any size int on the rhs
if rustc_front::util::is_shift_binop(op) {
let mut rhs_llty = val_ty(rhs);
let mut lhs_llty = val_ty(lhs);
if rhs_llty.kind() == Vector {
rhs_llty = rhs_llty.element_type()
}
if lhs_llty.kind() == Vector {
lhs_llty = lhs_llty.element_type()
}
let rhs_sz = rhs_llty.int_width();
let lhs_sz = lhs_llty.int_width();
if lhs_sz < rhs_sz {
trunc(rhs, lhs_llty)
} else if lhs_sz > rhs_sz {
// FIXME (#1877: If shifting by negative
// values becomes not undefined then this is wrong.
zext(rhs, lhs_llty)
} else {
rhs
}
} else {
rhs
}
}
pub fn llty_and_min_for_signed_ty<'blk, 'tcx>(cx: Block<'blk, 'tcx>,
val_t: Ty<'tcx>)
-> (Type, u64) {
match val_t.sty {
ty::TyInt(t) => {
let llty = Type::int_from_ty(cx.ccx(), t);
let min = match t {
ast::TyIs if llty == Type::i32(cx.ccx()) => i32::MIN as u64,
ast::TyIs => i64::MIN as u64,
ast::TyI8 => i8::MIN as u64,
ast::TyI16 => i16::MIN as u64,
ast::TyI32 => i32::MIN as u64,
ast::TyI64 => i64::MIN as u64,
};
(llty, min)
}
_ => unreachable!(),
}
}
pub fn fail_if_zero_or_overflows<'blk, 'tcx>(cx: Block<'blk, 'tcx>,
call_info: NodeIdAndSpan,
divrem: hir::BinOp,
lhs: ValueRef,
rhs: ValueRef,
rhs_t: Ty<'tcx>)
-> Block<'blk, 'tcx> {
let (zero_text, overflow_text) = if divrem.node == hir::BiDiv {
("attempted to divide by zero",
"attempted to divide with overflow")
} else {
("attempted remainder with a divisor of zero",
"attempted remainder with overflow")
};
let debug_loc = call_info.debug_loc();
let (is_zero, is_signed) = match rhs_t.sty {
ty::TyInt(t) => {
let zero = C_integral(Type::int_from_ty(cx.ccx(), t), 0, false);
(ICmp(cx, llvm::IntEQ, rhs, zero, debug_loc), true)
}
ty::TyUint(t) => {
let zero = C_integral(Type::uint_from_ty(cx.ccx(), t), 0, false);
(ICmp(cx, llvm::IntEQ, rhs, zero, debug_loc), false)
}
ty::TyStruct(def, _) if def.is_simd() => {
let mut res = C_bool(cx.ccx(), false);
for i in 0..rhs_t.simd_size(cx.tcx()) {
res = Or(cx,
res,
IsNull(cx, ExtractElement(cx, rhs, C_int(cx.ccx(), i as i64))),
debug_loc);
}
(res, false)
}
_ => {
cx.sess().bug(&format!("fail-if-zero on unexpected type: {}", rhs_t));
}
};
let bcx = with_cond(cx, is_zero, |bcx| {
controlflow::trans_fail(bcx, call_info, InternedString::new(zero_text))
});
// To quote LLVM's documentation for the sdiv instruction:
//
// Division by zero leads to undefined behavior. Overflow also leads
// to undefined behavior; this is a rare case, but can occur, for
// example, by doing a 32-bit division of -2147483648 by -1.
//
// In order to avoid undefined behavior, we perform runtime checks for
// signed division/remainder which would trigger overflow. For unsigned
// integers, no action beyond checking for zero need be taken.
if is_signed {
let (llty, min) = llty_and_min_for_signed_ty(cx, rhs_t);
let minus_one = ICmp(bcx,
llvm::IntEQ,
rhs,
C_integral(llty, !0, false),
debug_loc);
with_cond(bcx, minus_one, |bcx| {
let is_min = ICmp(bcx,
llvm::IntEQ,
lhs,
C_integral(llty, min, true),
debug_loc);
with_cond(bcx, is_min, |bcx| {
controlflow::trans_fail(bcx, call_info, InternedString::new(overflow_text))
})
})
} else {
bcx
}
}
pub fn trans_external_path<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
did: DefId,
t: Ty<'tcx>)
-> ValueRef {
let name = ccx.sess().cstore.item_symbol(did);
match t.sty {
ty::TyBareFn(_, ref fn_ty) => {
match ccx.sess().target.target.adjust_abi(fn_ty.abi) {
Rust | RustCall => {
get_extern_rust_fn(ccx, t, &name[..], did)
}
RustIntrinsic | PlatformIntrinsic => {
ccx.sess().bug("unexpected intrinsic in trans_external_path")
}
_ => {
let attrs = ccx.sess().cstore.item_attrs(did);
foreign::register_foreign_item_fn(ccx, fn_ty.abi, t, &name, &attrs)
}
}
}
_ => {
get_extern_const(ccx, did, t)
}
}
}
pub fn invoke<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
llfn: ValueRef,
llargs: &[ValueRef],
fn_ty: Ty<'tcx>,
debug_loc: DebugLoc)
-> (ValueRef, Block<'blk, 'tcx>) {
let _icx = push_ctxt("invoke_");
if bcx.unreachable.get() {
return (C_null(Type::i8(bcx.ccx())), bcx);
}
let attributes = attributes::from_fn_type(bcx.ccx(), fn_ty);
match bcx.opt_node_id {
None => {
debug!("invoke at ???");
}
Some(id) => {
debug!("invoke at {}", bcx.tcx().map.node_to_string(id));
}
}
if need_invoke(bcx) {
debug!("invoking {} at {:?}", bcx.val_to_string(llfn), bcx.llbb);
for &llarg in llargs {
debug!("arg: {}", bcx.val_to_string(llarg));
}
let normal_bcx = bcx.fcx.new_temp_block("normal-return");
let landing_pad = bcx.fcx.get_landing_pad();
let llresult = Invoke(bcx,
llfn,
&llargs[..],
normal_bcx.llbb,
landing_pad,
Some(attributes),
debug_loc);
return (llresult, normal_bcx);
} else {
debug!("calling {} at {:?}", bcx.val_to_string(llfn), bcx.llbb);
for &llarg in llargs {
debug!("arg: {}", bcx.val_to_string(llarg));
}
let llresult = Call(bcx, llfn, &llargs[..], Some(attributes), debug_loc);
return (llresult, bcx);
}
}
/// Returns whether this session's target will use SEH-based unwinding.
///
/// This is only true for MSVC targets, and even then the 64-bit MSVC target
/// currently uses SEH-ish unwinding with DWARF info tables to the side (same as
/// 64-bit MinGW) instead of "full SEH".
pub fn wants_msvc_seh(sess: &Session) -> bool {
sess.target.target.options.is_like_msvc && sess.target.target.arch == "x86"
}
pub fn avoid_invoke(bcx: Block) -> bool {
// FIXME(#25869) currently SEH-based unwinding is pretty buggy in LLVM and
// is being overhauled as this is being written. Until that
// time such that upstream LLVM's implementation is more solid
// and we start binding it we need to skip invokes for any
// target which wants SEH-based unwinding.
if bcx.sess().no_landing_pads() || wants_msvc_seh(bcx.sess()) {
true
} else if bcx.is_lpad {
// Avoid using invoke if we are already inside a landing pad.
true
} else {
false
}
}
pub fn need_invoke(bcx: Block) -> bool {
if avoid_invoke(bcx) {
false
} else {
bcx.fcx.needs_invoke()
}
}
pub fn load_if_immediate<'blk, 'tcx>(cx: Block<'blk, 'tcx>, v: ValueRef, t: Ty<'tcx>) -> ValueRef {
let _icx = push_ctxt("load_if_immediate");
if type_is_immediate(cx.ccx(), t) {
return load_ty(cx, v, t);
}
return v;
}
/// Helper for loading values from memory. Does the necessary conversion if the in-memory type
/// differs from the type used for SSA values. Also handles various special cases where the type
/// gives us better information about what we are loading.
pub fn load_ty<'blk, 'tcx>(cx: Block<'blk, 'tcx>, ptr: ValueRef, t: Ty<'tcx>) -> ValueRef {
if cx.unreachable.get() || type_is_zero_size(cx.ccx(), t) {
return C_undef(type_of::type_of(cx.ccx(), t));
}
let ptr = to_arg_ty_ptr(cx, ptr, t);
let align = type_of::align_of(cx.ccx(), t);
if type_is_immediate(cx.ccx(), t) && type_of::type_of(cx.ccx(), t).is_aggregate() {
let load = Load(cx, ptr);
unsafe {
llvm::LLVMSetAlignment(load, align);
}
return load;
}
unsafe {
let global = llvm::LLVMIsAGlobalVariable(ptr);
if !global.is_null() && llvm::LLVMIsGlobalConstant(global) == llvm::True {
let val = llvm::LLVMGetInitializer(global);
if !val.is_null() {
return to_arg_ty(cx, val, t);
}
}
}
let val = if t.is_bool() {
LoadRangeAssert(cx, ptr, 0, 2, llvm::False)
} else if t.is_char() {
// a char is a Unicode codepoint, and so takes values from 0
// to 0x10FFFF inclusive only.
LoadRangeAssert(cx, ptr, 0, 0x10FFFF + 1, llvm::False)
} else if (t.is_region_ptr() || t.is_unique()) && !common::type_is_fat_ptr(cx.tcx(), t) {
LoadNonNull(cx, ptr)
} else {
Load(cx, ptr)
};
unsafe {
llvm::LLVMSetAlignment(val, align);
}
to_arg_ty(cx, val, t)
}
/// Helper for storing values in memory. Does the necessary conversion if the in-memory type
/// differs from the type used for SSA values.
pub fn store_ty<'blk, 'tcx>(cx: Block<'blk, 'tcx>, v: ValueRef, dst: ValueRef, t: Ty<'tcx>) {
if cx.unreachable.get() {
return;
}
debug!("store_ty: {} : {:?} <- {}",
cx.val_to_string(dst),
t,
cx.val_to_string(v));
if common::type_is_fat_ptr(cx.tcx(), t) {
Store(cx,
ExtractValue(cx, v, abi::FAT_PTR_ADDR),
expr::get_dataptr(cx, dst));
Store(cx,
ExtractValue(cx, v, abi::FAT_PTR_EXTRA),
expr::get_meta(cx, dst));
} else {
let store = Store(cx, from_arg_ty(cx, v, t), to_arg_ty_ptr(cx, dst, t));
unsafe {
llvm::LLVMSetAlignment(store, type_of::align_of(cx.ccx(), t));
}
}
}
pub fn store_fat_ptr<'blk, 'tcx>(cx: Block<'blk, 'tcx>,
data: ValueRef,
extra: ValueRef,
dst: ValueRef,
_ty: Ty<'tcx>) {
// FIXME: emit metadata
Store(cx, data, expr::get_dataptr(cx, dst));
Store(cx, extra, expr::get_meta(cx, dst));
}
pub fn load_fat_ptr<'blk, 'tcx>(cx: Block<'blk, 'tcx>,
src: ValueRef,
_ty: Ty<'tcx>)
-> (ValueRef, ValueRef) {
// FIXME: emit metadata
(Load(cx, expr::get_dataptr(cx, src)),
Load(cx, expr::get_meta(cx, src)))
}
pub fn from_arg_ty(bcx: Block, val: ValueRef, ty: Ty) -> ValueRef {
if ty.is_bool() {
ZExt(bcx, val, Type::i8(bcx.ccx()))
} else {
val
}
}
pub fn to_arg_ty(bcx: Block, val: ValueRef, ty: Ty) -> ValueRef {
if ty.is_bool() {
Trunc(bcx, val, Type::i1(bcx.ccx()))
} else {
val
}
}
pub fn to_arg_ty_ptr<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, ptr: ValueRef, ty: Ty<'tcx>) -> ValueRef {
if type_is_immediate(bcx.ccx(), ty) && type_of::type_of(bcx.ccx(), ty).is_aggregate() {
// We want to pass small aggregates as immediate values, but using an aggregate LLVM type
// for this leads to bad optimizations, so its arg type is an appropriately sized integer
// and we have to convert it
BitCast(bcx, ptr, type_of::arg_type_of(bcx.ccx(), ty).ptr_to())
} else {
ptr
}
}
pub fn init_local<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, local: &hir::Local) -> Block<'blk, 'tcx> {
debug!("init_local(bcx={}, local.id={})", bcx.to_str(), local.id);
let _indenter = indenter();
let _icx = push_ctxt("init_local");
_match::store_local(bcx, local)
}
pub fn raw_block<'blk, 'tcx>(fcx: &'blk FunctionContext<'blk, 'tcx>,
is_lpad: bool,
llbb: BasicBlockRef)
-> Block<'blk, 'tcx> {
common::BlockS::new(llbb, is_lpad, None, fcx)
}
pub fn with_cond<'blk, 'tcx, F>(bcx: Block<'blk, 'tcx>, val: ValueRef, f: F) -> Block<'blk, 'tcx>
where F: FnOnce(Block<'blk, 'tcx>) -> Block<'blk, 'tcx>
{
let _icx = push_ctxt("with_cond");
if bcx.unreachable.get() || common::const_to_opt_uint(val) == Some(0) {
return bcx;
}
let fcx = bcx.fcx;
let next_cx = fcx.new_temp_block("next");
let cond_cx = fcx.new_temp_block("cond");
CondBr(bcx, val, cond_cx.llbb, next_cx.llbb, DebugLoc::None);
let after_cx = f(cond_cx);
if !after_cx.terminated.get() {
Br(after_cx, next_cx.llbb, DebugLoc::None);
}
next_cx
}
enum Lifetime { Start, End }
// If LLVM lifetime intrinsic support is enabled (i.e. optimizations
// on), and `ptr` is nonzero-sized, then extracts the size of `ptr`
// and the intrinsic for `lt` and passes them to `emit`, which is in
// charge of generating code to call the passed intrinsic on whatever
// block of generated code is targetted for the intrinsic.
//
// If LLVM lifetime intrinsic support is disabled (i.e. optimizations
// off) or `ptr` is zero-sized, then no-op (does not call `emit`).
fn core_lifetime_emit<'blk, 'tcx, F>(ccx: &'blk CrateContext<'blk, 'tcx>,
ptr: ValueRef,
lt: Lifetime,
emit: F)
where F: FnOnce(&'blk CrateContext<'blk, 'tcx>, machine::llsize, ValueRef)
{
if ccx.sess().opts.optimize == config::OptLevel::No {
return;
}
let _icx = push_ctxt(match lt {
Lifetime::Start => "lifetime_start",
Lifetime::End => "lifetime_end"
});
let size = machine::llsize_of_alloc(ccx, val_ty(ptr).element_type());
if size == 0 {
return;
}
let lifetime_intrinsic = ccx.get_intrinsic(match lt {
Lifetime::Start => "llvm.lifetime.start",
Lifetime::End => "llvm.lifetime.end"
});
emit(ccx, size, lifetime_intrinsic)
}
pub fn call_lifetime_start(cx: Block, ptr: ValueRef) {
core_lifetime_emit(cx.ccx(), ptr, Lifetime::Start, |ccx, size, lifetime_start| {
let ptr = PointerCast(cx, ptr, Type::i8p(ccx));
Call(cx,
lifetime_start,
&[C_u64(ccx, size), ptr],
None,
DebugLoc::None);
})
}
pub fn call_lifetime_end(cx: Block, ptr: ValueRef) {
core_lifetime_emit(cx.ccx(), ptr, Lifetime::End, |ccx, size, lifetime_end| {
let ptr = PointerCast(cx, ptr, Type::i8p(ccx));
Call(cx,
lifetime_end,
&[C_u64(ccx, size), ptr],
None,
DebugLoc::None);
})
}
// Generates code for resumption of unwind at the end of a landing pad.
pub fn trans_unwind_resume(bcx: Block, lpval: ValueRef) {
if !bcx.sess().target.target.options.custom_unwind_resume {
Resume(bcx, lpval);
} else {
let exc_ptr = ExtractValue(bcx, lpval, 0);
let llunwresume = bcx.fcx.eh_unwind_resume();
Call(bcx, llunwresume, &[exc_ptr], None, DebugLoc::None);
Unreachable(bcx);
}
}
pub fn call_memcpy(cx: Block, dst: ValueRef, src: ValueRef, n_bytes: ValueRef, align: u32) {
let _icx = push_ctxt("call_memcpy");
let ccx = cx.ccx();
let ptr_width = &ccx.sess().target.target.target_pointer_width[..];
let key = format!("llvm.memcpy.p0i8.p0i8.i{}", ptr_width);
let memcpy = ccx.get_intrinsic(&key);
let src_ptr = PointerCast(cx, src, Type::i8p(ccx));
let dst_ptr = PointerCast(cx, dst, Type::i8p(ccx));
let size = IntCast(cx, n_bytes, ccx.int_type());
let align = C_i32(ccx, align as i32);
let volatile = C_bool(ccx, false);
Call(cx,
memcpy,
&[dst_ptr, src_ptr, size, align, volatile],
None,
DebugLoc::None);
}
pub fn memcpy_ty<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, dst: ValueRef, src: ValueRef, t: Ty<'tcx>) {
let _icx = push_ctxt("memcpy_ty");
let ccx = bcx.ccx();
if type_is_zero_size(ccx, t) {
return;
}
if t.is_structural() {
let llty = type_of::type_of(ccx, t);
let llsz = llsize_of(ccx, llty);
let llalign = type_of::align_of(ccx, t);
call_memcpy(bcx, dst, src, llsz, llalign as u32);
} else if common::type_is_fat_ptr(bcx.tcx(), t) {
let (data, extra) = load_fat_ptr(bcx, src, t);
store_fat_ptr(bcx, data, extra, dst, t);
} else {
store_ty(bcx, load_ty(bcx, src, t), dst, t);
}
}
pub fn drop_done_fill_mem<'blk, 'tcx>(cx: Block<'blk, 'tcx>, llptr: ValueRef, t: Ty<'tcx>) {
if cx.unreachable.get() {
return;
}
let _icx = push_ctxt("drop_done_fill_mem");
let bcx = cx;
memfill(&B(bcx), llptr, t, adt::DTOR_DONE);
}
pub fn init_zero_mem<'blk, 'tcx>(cx: Block<'blk, 'tcx>, llptr: ValueRef, t: Ty<'tcx>) {
if cx.unreachable.get() {
return;
}
let _icx = push_ctxt("init_zero_mem");
let bcx = cx;
memfill(&B(bcx), llptr, t, 0);
}
// Always use this function instead of storing a constant byte to the memory
// in question. e.g. if you store a zero constant, LLVM will drown in vreg
// allocation for large data structures, and the generated code will be
// awful. (A telltale sign of this is large quantities of
// `mov [byte ptr foo],0` in the generated code.)
fn memfill<'a, 'tcx>(b: &Builder<'a, 'tcx>, llptr: ValueRef, ty: Ty<'tcx>, byte: u8) {
let _icx = push_ctxt("memfill");
let ccx = b.ccx;
let llty = type_of::type_of(ccx, ty);
let ptr_width = &ccx.sess().target.target.target_pointer_width[..];
let intrinsic_key = format!("llvm.memset.p0i8.i{}", ptr_width);
let llintrinsicfn = ccx.get_intrinsic(&intrinsic_key);
let llptr = b.pointercast(llptr, Type::i8(ccx).ptr_to());
let llzeroval = C_u8(ccx, byte);
let size = machine::llsize_of(ccx, llty);
let align = C_i32(ccx, type_of::align_of(ccx, ty) as i32);
let volatile = C_bool(ccx, false);
b.call(llintrinsicfn,
&[llptr, llzeroval, size, align, volatile],
None);
}
/// In general, when we create an scratch value in an alloca, the
/// creator may not know if the block (that initializes the scratch
/// with the desired value) actually dominates the cleanup associated
/// with the scratch value.
///
/// To deal with this, when we do an alloca (at the *start* of whole
/// function body), we optionally can also set the associated
/// dropped-flag state of the alloca to "dropped."
#[derive(Copy, Clone, Debug)]
pub enum InitAlloca {
/// Indicates that the state should have its associated drop flag
/// set to "dropped" at the point of allocation.
Dropped,
/// Indicates the value of the associated drop flag is irrelevant.
/// The embedded string literal is a programmer provided argument
/// for why. This is a safeguard forcing compiler devs to
/// document; it might be a good idea to also emit this as a
/// comment with the alloca itself when emitting LLVM output.ll.
Uninit(&'static str),
}
pub fn alloc_ty<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
t: Ty<'tcx>,
name: &str) -> ValueRef {
// pnkfelix: I do not know why alloc_ty meets the assumptions for
// passing Uninit, but it was never needed (even back when we had
// the original boolean `zero` flag on `lvalue_scratch_datum`).
alloc_ty_init(bcx, t, InitAlloca::Uninit("all alloc_ty are uninit"), name)
}
/// This variant of `fn alloc_ty` does not necessarily assume that the
/// alloca should be created with no initial value. Instead the caller
/// controls that assumption via the `init` flag.
///
/// Note that if the alloca *is* initialized via `init`, then we will
/// also inject an `llvm.lifetime.start` before that initialization
/// occurs, and thus callers should not call_lifetime_start
/// themselves. But if `init` says "uninitialized", then callers are
/// in charge of choosing where to call_lifetime_start and
/// subsequently populate the alloca.
///
/// (See related discussion on PR #30823.)
pub fn alloc_ty_init<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
t: Ty<'tcx>,
init: InitAlloca,
name: &str) -> ValueRef {
let _icx = push_ctxt("alloc_ty");
let ccx = bcx.ccx();
let ty = type_of::type_of(ccx, t);
assert!(!t.has_param_types());
match init {
InitAlloca::Dropped => alloca_dropped(bcx, t, name),
InitAlloca::Uninit(_) => alloca(bcx, ty, name),
}
}
pub fn alloca_dropped<'blk, 'tcx>(cx: Block<'blk, 'tcx>, ty: Ty<'tcx>, name: &str) -> ValueRef {
let _icx = push_ctxt("alloca_dropped");
let llty = type_of::type_of(cx.ccx(), ty);
if cx.unreachable.get() {
unsafe { return llvm::LLVMGetUndef(llty.ptr_to().to_ref()); }
}
let p = alloca(cx, llty, name);
let b = cx.fcx.ccx.builder();
b.position_before(cx.fcx.alloca_insert_pt.get().unwrap());
// This is just like `call_lifetime_start` (but latter expects a
// Block, which we do not have for `alloca_insert_pt`).
core_lifetime_emit(cx.ccx(), p, Lifetime::Start, |ccx, size, lifetime_start| {
let ptr = b.pointercast(p, Type::i8p(ccx));
b.call(lifetime_start, &[C_u64(ccx, size), ptr], None);
});
memfill(&b, p, ty, adt::DTOR_DONE);
p
}
pub fn alloca(cx: Block, ty: Type, name: &str) -> ValueRef {
let _icx = push_ctxt("alloca");
if cx.unreachable.get() {
unsafe {
return llvm::LLVMGetUndef(ty.ptr_to().to_ref());
}
}
debuginfo::clear_source_location(cx.fcx);
Alloca(cx, ty, name)
}
pub fn set_value_name(val: ValueRef, name: &str) {
unsafe {
let name = CString::new(name).unwrap();
llvm::LLVMSetValueName(val, name.as_ptr());
}
}
// Creates the alloca slot which holds the pointer to the slot for the final return value
pub fn make_return_slot_pointer<'a, 'tcx>(fcx: &FunctionContext<'a, 'tcx>,
output_type: Ty<'tcx>)
-> ValueRef {
let lloutputtype = type_of::type_of(fcx.ccx, output_type);
// We create an alloca to hold a pointer of type `output_type`
// which will hold the pointer to the right alloca which has the
// final ret value
if fcx.needs_ret_allocas {
// Let's create the stack slot
let slot = AllocaFcx(fcx, lloutputtype.ptr_to(), "llretslotptr");
// and if we're using an out pointer, then store that in our newly made slot
if type_of::return_uses_outptr(fcx.ccx, output_type) {
let outptr = get_param(fcx.llfn, 0);
let b = fcx.ccx.builder();
b.position_before(fcx.alloca_insert_pt.get().unwrap());
b.store(outptr, slot);
}
slot
// But if there are no nested returns, we skip the indirection and have a single
// retslot
} else {
if type_of::return_uses_outptr(fcx.ccx, output_type) {
get_param(fcx.llfn, 0)
} else {
AllocaFcx(fcx, lloutputtype, "sret_slot")
}
}
}
struct FindNestedReturn {
found: bool,
}
impl FindNestedReturn {
fn new() -> FindNestedReturn {
FindNestedReturn {
found: false,
}
}
}
impl<'v> Visitor<'v> for FindNestedReturn {
fn visit_expr(&mut self, e: &hir::Expr) {
match e.node {
hir::ExprRet(..) => {
self.found = true;
}
_ => intravisit::walk_expr(self, e),
}
}
}
fn build_cfg(tcx: &ty::ctxt, id: ast::NodeId) -> (ast::NodeId, Option<cfg::CFG>) {
let blk = match tcx.map.find(id) {
Some(hir_map::NodeItem(i)) => {
match i.node {
hir::ItemFn(_, _, _, _, _, ref blk) => {
blk
}
_ => tcx.sess.bug("unexpected item variant in has_nested_returns"),
}
}
Some(hir_map::NodeTraitItem(trait_item)) => {
match trait_item.node {
hir::MethodTraitItem(_, Some(ref body)) => body,
_ => {
tcx.sess.bug("unexpected variant: trait item other than a provided method in \
has_nested_returns")
}
}
}
Some(hir_map::NodeImplItem(impl_item)) => {
match impl_item.node {
hir::ImplItemKind::Method(_, ref body) => body,
_ => {
tcx.sess.bug("unexpected variant: non-method impl item in has_nested_returns")
}
}
}
Some(hir_map::NodeExpr(e)) => {
match e.node {
hir::ExprClosure(_, _, ref blk) => blk,
_ => tcx.sess.bug("unexpected expr variant in has_nested_returns"),
}
}
Some(hir_map::NodeVariant(..)) |
Some(hir_map::NodeStructCtor(..)) => return (ast::DUMMY_NODE_ID, None),
// glue, shims, etc
None if id == ast::DUMMY_NODE_ID => return (ast::DUMMY_NODE_ID, None),
_ => tcx.sess.bug(&format!("unexpected variant in has_nested_returns: {}",
tcx.map.path_to_string(id))),
};
(blk.id, Some(cfg::CFG::new(tcx, blk)))
}
// Checks for the presence of "nested returns" in a function.
// Nested returns are when the inner expression of a return expression
// (the 'expr' in 'return expr') contains a return expression. Only cases
// where the outer return is actually reachable are considered. Implicit
// returns from the end of blocks are considered as well.
//
// This check is needed to handle the case where the inner expression is
// part of a larger expression that may have already partially-filled the
// return slot alloca. This can cause errors related to clean-up due to
// the clobbering of the existing value in the return slot.
fn has_nested_returns(tcx: &ty::ctxt, cfg: &cfg::CFG, blk_id: ast::NodeId) -> bool {
for index in cfg.graph.depth_traverse(cfg.entry) {
let n = cfg.graph.node_data(index);
match tcx.map.find(n.id()) {
Some(hir_map::NodeExpr(ex)) => {
if let hir::ExprRet(Some(ref ret_expr)) = ex.node {
let mut visitor = FindNestedReturn::new();
intravisit::walk_expr(&mut visitor, &**ret_expr);
if visitor.found {
return true;
}
}
}
Some(hir_map::NodeBlock(blk)) if blk.id == blk_id => {
let mut visitor = FindNestedReturn::new();
walk_list!(&mut visitor, visit_expr, &blk.expr);
if visitor.found {
return true;
}
}
_ => {}
}
}
return false;
}
// NB: must keep 4 fns in sync:
//
// - type_of_fn
// - create_datums_for_fn_args.
// - new_fn_ctxt
// - trans_args
//
// Be warned! You must call `init_function` before doing anything with the
// returned function context.
pub fn new_fn_ctxt<'a, 'tcx>(ccx: &'a CrateContext<'a, 'tcx>,
llfndecl: ValueRef,
id: ast::NodeId,
has_env: bool,
output_type: ty::FnOutput<'tcx>,
param_substs: &'tcx Substs<'tcx>,
sp: Option<Span>,
block_arena: &'a TypedArena<common::BlockS<'a, 'tcx>>)
-> FunctionContext<'a, 'tcx> {
common::validate_substs(param_substs);
debug!("new_fn_ctxt(path={}, id={}, param_substs={:?})",
if id == !0 {
"".to_string()
} else {
ccx.tcx().map.path_to_string(id).to_string()
},
id,
param_substs);
let uses_outptr = match output_type {
ty::FnConverging(output_type) => {
let substd_output_type = monomorphize::apply_param_substs(ccx.tcx(),
param_substs,
&output_type);
type_of::return_uses_outptr(ccx, substd_output_type)
}
ty::FnDiverging => false,
};
let debug_context = debuginfo::create_function_debug_context(ccx, id, param_substs, llfndecl);
let (blk_id, cfg) = build_cfg(ccx.tcx(), id);
let nested_returns = if let Some(ref cfg) = cfg {
has_nested_returns(ccx.tcx(), cfg, blk_id)
} else {
false
};
let mir = ccx.mir_map().get(&id);
let mut fcx = FunctionContext {
mir: mir,
llfn: llfndecl,
llenv: None,
llretslotptr: Cell::new(None),
param_env: ccx.tcx().empty_parameter_environment(),
alloca_insert_pt: Cell::new(None),
llreturn: Cell::new(None),
needs_ret_allocas: nested_returns,
personality: Cell::new(None),
caller_expects_out_pointer: uses_outptr,
lllocals: RefCell::new(NodeMap()),
llupvars: RefCell::new(NodeMap()),
lldropflag_hints: RefCell::new(DropFlagHintsMap::new()),
id: id,
param_substs: param_substs,
span: sp,
block_arena: block_arena,
ccx: ccx,
debug_context: debug_context,
scopes: RefCell::new(Vec::new()),
cfg: cfg,
};
if has_env {
fcx.llenv = Some(get_param(fcx.llfn, fcx.env_arg_pos() as c_uint))
}
fcx
}
/// Performs setup on a newly created function, creating the entry scope block
/// and allocating space for the return pointer.
pub fn init_function<'a, 'tcx>(fcx: &'a FunctionContext<'a, 'tcx>,
skip_retptr: bool,
output: ty::FnOutput<'tcx>)
-> Block<'a, 'tcx> {
let entry_bcx = fcx.new_temp_block("entry-block");
// Use a dummy instruction as the insertion point for all allocas.
// This is later removed in FunctionContext::cleanup.
fcx.alloca_insert_pt.set(Some(unsafe {
Load(entry_bcx, C_null(Type::i8p(fcx.ccx)));
llvm::LLVMGetFirstInstruction(entry_bcx.llbb)
}));
if let ty::FnConverging(output_type) = output {
// This shouldn't need to recompute the return type,
// as new_fn_ctxt did it already.
let substd_output_type = fcx.monomorphize(&output_type);
if !return_type_is_void(fcx.ccx, substd_output_type) {
// If the function returns nil/bot, there is no real return
// value, so do not set `llretslotptr`.
if !skip_retptr || fcx.caller_expects_out_pointer {
// Otherwise, we normally allocate the llretslotptr, unless we
// have been instructed to skip it for immediate return
// values.
fcx.llretslotptr.set(Some(make_return_slot_pointer(fcx, substd_output_type)));
}
}
}
// Create the drop-flag hints for every unfragmented path in the function.
let tcx = fcx.ccx.tcx();
let fn_did = tcx.map.local_def_id(fcx.id);
let tables = tcx.tables.borrow();
let mut hints = fcx.lldropflag_hints.borrow_mut();
let fragment_infos = tcx.fragment_infos.borrow();
// Intern table for drop-flag hint datums.
let mut seen = HashMap::new();
if let Some(fragment_infos) = fragment_infos.get(&fn_did) {
for &info in fragment_infos {
let make_datum = |id| {
let init_val = C_u8(fcx.ccx, adt::DTOR_NEEDED_HINT);
let llname = &format!("dropflag_hint_{}", id);
debug!("adding hint {}", llname);
let ty = tcx.types.u8;
let ptr = alloc_ty(entry_bcx, ty, llname);
Store(entry_bcx, init_val, ptr);
let flag = datum::Lvalue::new_dropflag_hint("base::init_function");
datum::Datum::new(ptr, ty, flag)
};
let (var, datum) = match info {
ty::FragmentInfo::Moved { var, .. } |
ty::FragmentInfo::Assigned { var, .. } => {
let opt_datum = seen.get(&var).cloned().unwrap_or_else(|| {
let ty = tables.node_types[&var];
if fcx.type_needs_drop(ty) {
let datum = make_datum(var);
seen.insert(var, Some(datum.clone()));
Some(datum)
} else {
// No drop call needed, so we don't need a dropflag hint
None
}
});
if let Some(datum) = opt_datum {
(var, datum)
} else {
continue
}
}
};
match info {
ty::FragmentInfo::Moved { move_expr: expr_id, .. } => {
debug!("FragmentInfo::Moved insert drop hint for {}", expr_id);
hints.insert(expr_id, DropHint::new(var, datum));
}
ty::FragmentInfo::Assigned { assignee_id: expr_id, .. } => {
debug!("FragmentInfo::Assigned insert drop hint for {}", expr_id);
hints.insert(expr_id, DropHint::new(var, datum));
}
}
}
}
entry_bcx
}
// NB: must keep 4 fns in sync:
//
// - type_of_fn
// - create_datums_for_fn_args.
// - new_fn_ctxt
// - trans_args
pub fn arg_kind<'a, 'tcx>(cx: &FunctionContext<'a, 'tcx>, t: Ty<'tcx>) -> datum::Rvalue {
use trans::datum::{ByRef, ByValue};
datum::Rvalue {
mode: if arg_is_indirect(cx.ccx, t) { ByRef } else { ByValue }
}
}
// create_datums_for_fn_args: creates lvalue datums for each of the
// incoming function arguments.
pub fn create_datums_for_fn_args<'a, 'tcx>(mut bcx: Block<'a, 'tcx>,
args: &[hir::Arg],
arg_tys: &[Ty<'tcx>],
has_tupled_arg: bool,
arg_scope: cleanup::CustomScopeIndex)
-> Block<'a, 'tcx> {
let _icx = push_ctxt("create_datums_for_fn_args");
let fcx = bcx.fcx;
let arg_scope_id = cleanup::CustomScope(arg_scope);
debug!("create_datums_for_fn_args");
// Return an array wrapping the ValueRefs that we get from `get_param` for
// each argument into datums.
//
// For certain mode/type combinations, the raw llarg values are passed
// by value. However, within the fn body itself, we want to always
// have all locals and arguments be by-ref so that we can cancel the
// cleanup and for better interaction with LLVM's debug info. So, if
// the argument would be passed by value, we store it into an alloca.
// This alloca should be optimized away by LLVM's mem-to-reg pass in
// the event it's not truly needed.
let mut idx = fcx.arg_offset() as c_uint;
let uninit_reason = InitAlloca::Uninit("fn_arg populate dominates dtor");
for (i, &arg_ty) in arg_tys.iter().enumerate() {
let arg_datum = if !has_tupled_arg || i < arg_tys.len() - 1 {
if type_of::arg_is_indirect(bcx.ccx(), arg_ty) &&
bcx.sess().opts.debuginfo != FullDebugInfo {
// Don't copy an indirect argument to an alloca, the caller
// already put it in a temporary alloca and gave it up, unless
// we emit extra-debug-info, which requires local allocas :(.
let llarg = get_param(fcx.llfn, idx);
idx += 1;
bcx.fcx.schedule_lifetime_end(arg_scope_id, llarg);
bcx.fcx.schedule_drop_mem(arg_scope_id, llarg, arg_ty, None);
datum::Datum::new(llarg,
arg_ty,
datum::Lvalue::new("create_datum_for_fn_args"))
} else if common::type_is_fat_ptr(bcx.tcx(), arg_ty) {
let data = get_param(fcx.llfn, idx);
let extra = get_param(fcx.llfn, idx + 1);
idx += 2;
unpack_datum!(bcx, datum::lvalue_scratch_datum(bcx, arg_ty, "", uninit_reason,
arg_scope_id, (data, extra),
|(data, extra), bcx, dst| {
debug!("populate call for create_datum_for_fn_args \
early fat arg, on arg[{}] ty={:?}", i, arg_ty);
Store(bcx, data, expr::get_dataptr(bcx, dst));
Store(bcx, extra, expr::get_meta(bcx, dst));
bcx
}))
} else {
let llarg = get_param(fcx.llfn, idx);
idx += 1;
let tmp = datum::Datum::new(llarg, arg_ty, arg_kind(fcx, arg_ty));
unpack_datum!(bcx,
datum::lvalue_scratch_datum(bcx,
arg_ty,
"",
uninit_reason,
arg_scope_id,
tmp,
|tmp, bcx, dst| {
debug!("populate call for create_datum_for_fn_args \
early thin arg, on arg[{}] ty={:?}", i, arg_ty);
tmp.store_to(bcx, dst)
}))
}
} else {
// FIXME(pcwalton): Reduce the amount of code bloat this is responsible for.
match arg_ty.sty {
ty::TyTuple(ref tupled_arg_tys) => {
unpack_datum!(bcx,
datum::lvalue_scratch_datum(bcx,
arg_ty,
"tupled_args",
uninit_reason,
arg_scope_id,
(),
|(),
mut bcx,
llval| {
debug!("populate call for create_datum_for_fn_args \
tupled_args, on arg[{}] ty={:?}", i, arg_ty);
for (j, &tupled_arg_ty) in
tupled_arg_tys.iter().enumerate() {
let lldest = StructGEP(bcx, llval, j);
if common::type_is_fat_ptr(bcx.tcx(), tupled_arg_ty) {
let data = get_param(bcx.fcx.llfn, idx);
let extra = get_param(bcx.fcx.llfn, idx + 1);
Store(bcx, data, expr::get_dataptr(bcx, lldest));
Store(bcx, extra, expr::get_meta(bcx, lldest));
idx += 2;
} else {
let datum = datum::Datum::new(
get_param(bcx.fcx.llfn, idx),
tupled_arg_ty,
arg_kind(bcx.fcx, tupled_arg_ty));
idx += 1;
bcx = datum.store_to(bcx, lldest);
};
}
bcx
}))
}
_ => {
bcx.tcx()
.sess
.bug("last argument of a function with `rust-call` ABI isn't a tuple?!")
}
}
};
let pat = &*args[i].pat;
bcx = if let Some(name) = simple_name(pat) {
// Generate nicer LLVM for the common case of fn a pattern
// like `x: T`
set_value_name(arg_datum.val, &bcx.name(name));
bcx.fcx.lllocals.borrow_mut().insert(pat.id, arg_datum);
bcx
} else {
// General path. Copy out the values that are used in the
// pattern.
_match::bind_irrefutable_pat(bcx, pat, arg_datum.match_input(), arg_scope_id)
};
debuginfo::create_argument_metadata(bcx, &args[i]);
}
bcx
}
// Ties up the llstaticallocas -> llloadenv -> lltop edges,
// and builds the return block.
pub fn finish_fn<'blk, 'tcx>(fcx: &'blk FunctionContext<'blk, 'tcx>,
last_bcx: Block<'blk, 'tcx>,
retty: ty::FnOutput<'tcx>,
ret_debug_loc: DebugLoc) {
let _icx = push_ctxt("finish_fn");
let ret_cx = match fcx.llreturn.get() {
Some(llreturn) => {
if !last_bcx.terminated.get() {
Br(last_bcx, llreturn, DebugLoc::None);
}
raw_block(fcx, false, llreturn)
}
None => last_bcx,
};
// This shouldn't need to recompute the return type,
// as new_fn_ctxt did it already.
let substd_retty = fcx.monomorphize(&retty);
build_return_block(fcx, ret_cx, substd_retty, ret_debug_loc);
debuginfo::clear_source_location(fcx);
fcx.cleanup();
}
// Builds the return block for a function.
pub fn build_return_block<'blk, 'tcx>(fcx: &FunctionContext<'blk, 'tcx>,
ret_cx: Block<'blk, 'tcx>,
retty: ty::FnOutput<'tcx>,
ret_debug_location: DebugLoc) {
if fcx.llretslotptr.get().is_none() ||
(!fcx.needs_ret_allocas && fcx.caller_expects_out_pointer) {
return RetVoid(ret_cx, ret_debug_location);
}
let retslot = if fcx.needs_ret_allocas {
Load(ret_cx, fcx.llretslotptr.get().unwrap())
} else {
fcx.llretslotptr.get().unwrap()
};
let retptr = Value(retslot);
match retptr.get_dominating_store(ret_cx) {
// If there's only a single store to the ret slot, we can directly return
// the value that was stored and omit the store and the alloca
Some(s) => {
let retval = s.get_operand(0).unwrap().get();
s.erase_from_parent();
if retptr.has_no_uses() {
retptr.erase_from_parent();
}
let retval = if retty == ty::FnConverging(fcx.ccx.tcx().types.bool) {
Trunc(ret_cx, retval, Type::i1(fcx.ccx))
} else {
retval
};
if fcx.caller_expects_out_pointer {
if let ty::FnConverging(retty) = retty {
store_ty(ret_cx, retval, get_param(fcx.llfn, 0), retty);
}
RetVoid(ret_cx, ret_debug_location)
} else {
Ret(ret_cx, retval, ret_debug_location)
}
}
// Otherwise, copy the return value to the ret slot
None => match retty {
ty::FnConverging(retty) => {
if fcx.caller_expects_out_pointer {
memcpy_ty(ret_cx, get_param(fcx.llfn, 0), retslot, retty);
RetVoid(ret_cx, ret_debug_location)
} else {
Ret(ret_cx, load_ty(ret_cx, retslot, retty), ret_debug_location)
}
}
ty::FnDiverging => {
if fcx.caller_expects_out_pointer {
RetVoid(ret_cx, ret_debug_location)
} else {
Ret(ret_cx, C_undef(Type::nil(fcx.ccx)), ret_debug_location)
}
}
},
}
}
/// Builds an LLVM function out of a source function.
///
/// If the function closes over its environment a closure will be returned.
pub fn trans_closure<'a, 'b, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
decl: &hir::FnDecl,
body: &hir::Block,
llfndecl: ValueRef,
param_substs: &'tcx Substs<'tcx>,
fn_ast_id: ast::NodeId,
attributes: &[ast::Attribute],
output_type: ty::FnOutput<'tcx>,
abi: Abi,
closure_env: closure::ClosureEnv<'b>) {
ccx.stats().n_closures.set(ccx.stats().n_closures.get() + 1);
let _icx = push_ctxt("trans_closure");
attributes::emit_uwtable(llfndecl, true);
debug!("trans_closure(..., param_substs={:?})", param_substs);
let has_env = match closure_env {
closure::ClosureEnv::Closure(..) => true,
closure::ClosureEnv::NotClosure => false,
};
let (arena, fcx): (TypedArena<_>, FunctionContext);
arena = TypedArena::new();
fcx = new_fn_ctxt(ccx,
llfndecl,
fn_ast_id,
has_env,
output_type,
param_substs,
Some(body.span),
&arena);
let mut bcx = init_function(&fcx, false, output_type);
if attributes.iter().any(|item| item.check_name("rustc_mir")) {
mir::trans_mir(bcx);
fcx.cleanup();
return;
}
// cleanup scope for the incoming arguments
let fn_cleanup_debug_loc = debuginfo::get_cleanup_debug_loc_for_ast_node(ccx,
fn_ast_id,
body.span,
true);
let arg_scope = fcx.push_custom_cleanup_scope_with_debug_loc(fn_cleanup_debug_loc);
let block_ty = node_id_type(bcx, body.id);
// Set up arguments to the function.
let monomorphized_arg_types = decl.inputs
.iter()
.map(|arg| node_id_type(bcx, arg.id))
.collect::<Vec<_>>();
for monomorphized_arg_type in &monomorphized_arg_types {
debug!("trans_closure: monomorphized_arg_type: {:?}",
monomorphized_arg_type);
}
debug!("trans_closure: function lltype: {}",
bcx.fcx.ccx.tn().val_to_string(bcx.fcx.llfn));
let has_tupled_arg = match closure_env {
closure::ClosureEnv::NotClosure => abi == RustCall,
_ => false,
};
bcx = create_datums_for_fn_args(bcx,
&decl.inputs,
&monomorphized_arg_types,
has_tupled_arg,
arg_scope);
bcx = closure_env.load(bcx, cleanup::CustomScope(arg_scope));
// Up until here, IR instructions for this function have explicitly not been annotated with
// source code location, so we don't step into call setup code. From here on, source location
// emitting should be enabled.
debuginfo::start_emitting_source_locations(&fcx);
let dest = match fcx.llretslotptr.get() {
Some(_) => expr::SaveIn(fcx.get_ret_slot(bcx, ty::FnConverging(block_ty), "iret_slot")),
None => {
assert!(type_is_zero_size(bcx.ccx(), block_ty));
expr::Ignore
}
};
// This call to trans_block is the place where we bridge between
// translation calls that don't have a return value (trans_crate,
// trans_mod, trans_item, et cetera) and those that do
// (trans_block, trans_expr, et cetera).
bcx = controlflow::trans_block(bcx, body, dest);
match dest {
expr::SaveIn(slot) if fcx.needs_ret_allocas => {
Store(bcx, slot, fcx.llretslotptr.get().unwrap());
}
_ => {}
}
match fcx.llreturn.get() {
Some(_) => {
Br(bcx, fcx.return_exit_block(), DebugLoc::None);
fcx.pop_custom_cleanup_scope(arg_scope);
}
None => {
// Microoptimization writ large: avoid creating a separate
// llreturn basic block
bcx = fcx.pop_and_trans_custom_cleanup_scope(bcx, arg_scope);
}
};
// Put return block after all other blocks.
// This somewhat improves single-stepping experience in debugger.
unsafe {
let llreturn = fcx.llreturn.get();
if let Some(llreturn) = llreturn {
llvm::LLVMMoveBasicBlockAfter(llreturn, bcx.llbb);
}
}
let ret_debug_loc = DebugLoc::At(fn_cleanup_debug_loc.id, fn_cleanup_debug_loc.span);
// Insert the mandatory first few basic blocks before lltop.
finish_fn(&fcx, bcx, output_type, ret_debug_loc);
}
/// Creates an LLVM function corresponding to a source language function.
pub fn trans_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
decl: &hir::FnDecl,
body: &hir::Block,
llfndecl: ValueRef,
param_substs: &'tcx Substs<'tcx>,
id: ast::NodeId,
attrs: &[ast::Attribute]) {
let _s = StatRecorder::new(ccx, ccx.tcx().map.path_to_string(id).to_string());
debug!("trans_fn(param_substs={:?})", param_substs);
let _icx = push_ctxt("trans_fn");
let fn_ty = ccx.tcx().node_id_to_type(id);
let fn_ty = monomorphize::apply_param_substs(ccx.tcx(), param_substs, &fn_ty);
let sig = fn_ty.fn_sig();
let sig = ccx.tcx().erase_late_bound_regions(&sig);
let sig = infer::normalize_associated_type(ccx.tcx(), &sig);
let output_type = sig.output;
let abi = fn_ty.fn_abi();
trans_closure(ccx,
decl,
body,
llfndecl,
param_substs,
id,
attrs,
output_type,
abi,
closure::ClosureEnv::NotClosure);
}
pub fn trans_enum_variant<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
ctor_id: ast::NodeId,
disr: Disr,
param_substs: &'tcx Substs<'tcx>,
llfndecl: ValueRef) {
let _icx = push_ctxt("trans_enum_variant");
trans_enum_variant_or_tuple_like_struct(ccx, ctor_id, disr, param_substs, llfndecl);
}
pub fn trans_named_tuple_constructor<'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
ctor_ty: Ty<'tcx>,
disr: Disr,
args: callee::CallArgs,
dest: expr::Dest,
debug_loc: DebugLoc)
-> Result<'blk, 'tcx> {
let ccx = bcx.fcx.ccx;
let sig = ccx.tcx().erase_late_bound_regions(&ctor_ty.fn_sig());
let sig = infer::normalize_associated_type(ccx.tcx(), &sig);
let result_ty = sig.output.unwrap();
// Get location to store the result. If the user does not care about
// the result, just make a stack slot
let llresult = match dest {
expr::SaveIn(d) => d,
expr::Ignore => {
if !type_is_zero_size(ccx, result_ty) {
let llresult = alloc_ty(bcx, result_ty, "constructor_result");
call_lifetime_start(bcx, llresult);
llresult
} else {
C_undef(type_of::type_of(ccx, result_ty).ptr_to())
}
}
};
if !type_is_zero_size(ccx, result_ty) {
match args {
callee::ArgExprs(exprs) => {
let fields = exprs.iter().map(|x| &**x).enumerate().collect::<Vec<_>>();
bcx = expr::trans_adt(bcx,
result_ty,
disr,
&fields[..],
None,
expr::SaveIn(llresult),
debug_loc);
}
_ => ccx.sess().bug("expected expr as arguments for variant/struct tuple constructor"),
}
} else {
// Just eval all the expressions (if any). Since expressions in Rust can have arbitrary
// contents, there could be side-effects we need from them.
match args {
callee::ArgExprs(exprs) => {
for expr in exprs {
bcx = expr::trans_into(bcx, expr, expr::Ignore);
}
}
_ => (),
}
}
// If the caller doesn't care about the result
// drop the temporary we made
let bcx = match dest {
expr::SaveIn(_) => bcx,
expr::Ignore => {
let bcx = glue::drop_ty(bcx, llresult, result_ty, debug_loc);
if !type_is_zero_size(ccx, result_ty) {
call_lifetime_end(bcx, llresult);
}
bcx
}
};
Result::new(bcx, llresult)
}
pub fn trans_tuple_struct<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
ctor_id: ast::NodeId,
param_substs: &'tcx Substs<'tcx>,
llfndecl: ValueRef) {
let _icx = push_ctxt("trans_tuple_struct");
trans_enum_variant_or_tuple_like_struct(ccx, ctor_id, Disr(0), param_substs, llfndecl);
}
fn trans_enum_variant_or_tuple_like_struct<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
ctor_id: ast::NodeId,
disr: Disr,
param_substs: &'tcx Substs<'tcx>,
llfndecl: ValueRef) {
let ctor_ty = ccx.tcx().node_id_to_type(ctor_id);
let ctor_ty = monomorphize::apply_param_substs(ccx.tcx(), param_substs, &ctor_ty);
let sig = ccx.tcx().erase_late_bound_regions(&ctor_ty.fn_sig());
let sig = infer::normalize_associated_type(ccx.tcx(), &sig);
let arg_tys = sig.inputs;
let result_ty = sig.output;
let (arena, fcx): (TypedArena<_>, FunctionContext);
arena = TypedArena::new();
fcx = new_fn_ctxt(ccx,
llfndecl,
ctor_id,
false,
result_ty,
param_substs,
None,
&arena);
let bcx = init_function(&fcx, false, result_ty);
assert!(!fcx.needs_ret_allocas);
if !type_is_zero_size(fcx.ccx, result_ty.unwrap()) {
let dest = fcx.get_ret_slot(bcx, result_ty, "eret_slot");
let dest_val = adt::MaybeSizedValue::sized(dest); // Can return unsized value
let repr = adt::represent_type(ccx, result_ty.unwrap());
let mut llarg_idx = fcx.arg_offset() as c_uint;
for (i, arg_ty) in arg_tys.into_iter().enumerate() {
let lldestptr = adt::trans_field_ptr(bcx, &*repr, dest_val, Disr::from(disr), i);
if common::type_is_fat_ptr(bcx.tcx(), arg_ty) {
Store(bcx,
get_param(fcx.llfn, llarg_idx),
expr::get_dataptr(bcx, lldestptr));
Store(bcx,
get_param(fcx.llfn, llarg_idx + 1),
expr::get_meta(bcx, lldestptr));
llarg_idx += 2;
} else {
let arg = get_param(fcx.llfn, llarg_idx);
llarg_idx += 1;
if arg_is_indirect(ccx, arg_ty) {
memcpy_ty(bcx, lldestptr, arg, arg_ty);
} else {
store_ty(bcx, arg, lldestptr, arg_ty);
}
}
}
adt::trans_set_discr(bcx, &*repr, dest, disr);
}
finish_fn(&fcx, bcx, result_ty, DebugLoc::None);
}
fn enum_variant_size_lint(ccx: &CrateContext, enum_def: &hir::EnumDef, sp: Span, id: ast::NodeId) {
let mut sizes = Vec::new(); // does no allocation if no pushes, thankfully
let print_info = ccx.sess().print_enum_sizes();
let levels = ccx.tcx().node_lint_levels.borrow();
let lint_id = lint::LintId::of(lint::builtin::VARIANT_SIZE_DIFFERENCES);
let lvlsrc = levels.get(&(id, lint_id));
let is_allow = lvlsrc.map_or(true, |&(lvl, _)| lvl == lint::Allow);
if is_allow && !print_info {
// we're not interested in anything here
return;
}
let ty = ccx.tcx().node_id_to_type(id);
let avar = adt::represent_type(ccx, ty);
match *avar {
adt::General(_, ref variants, _) => {
for var in variants {
let mut size = 0;
for field in var.fields.iter().skip(1) {
// skip the discriminant
size += llsize_of_real(ccx, sizing_type_of(ccx, *field));
}
sizes.push(size);
}
},
_ => { /* its size is either constant or unimportant */ }
}
let (largest, slargest, largest_index) = sizes.iter().enumerate().fold((0, 0, 0),
|(l, s, li), (idx, &size)|
if size > l {
(size, l, idx)
} else if size > s {
(l, size, li)
} else {
(l, s, li)
}
);
// FIXME(#30505) Should use logging for this.
if print_info {
let llty = type_of::sizing_type_of(ccx, ty);
let sess = &ccx.tcx().sess;
sess.span_note_without_error(sp,
&*format!("total size: {} bytes", llsize_of_real(ccx, llty)));
match *avar {
adt::General(..) => {
for (i, var) in enum_def.variants.iter().enumerate() {
ccx.tcx()
.sess
.span_note_without_error(var.span,
&*format!("variant data: {} bytes", sizes[i]));
}
}
_ => {}
}
}
// we only warn if the largest variant is at least thrice as large as
// the second-largest.
if !is_allow && largest > slargest * 3 && slargest > 0 {
// Use lint::raw_emit_lint rather than sess.add_lint because the lint-printing
// pass for the latter already ran.
lint::raw_struct_lint(&ccx.tcx().sess,
&ccx.tcx().sess.lint_store.borrow(),
lint::builtin::VARIANT_SIZE_DIFFERENCES,
*lvlsrc.unwrap(),
Some(sp),
&format!("enum variant is more than three times larger ({} bytes) \
than the next largest (ignoring padding)",
largest))
.span_note(enum_def.variants[largest_index].span,
"this variant is the largest")
.emit();
}
}
pub fn llvm_linkage_by_name(name: &str) -> Option<Linkage> {
// Use the names from src/llvm/docs/LangRef.rst here. Most types are only
// applicable to variable declarations and may not really make sense for
// Rust code in the first place but whitelist them anyway and trust that
// the user knows what s/he's doing. Who knows, unanticipated use cases
// may pop up in the future.
//
// ghost, dllimport, dllexport and linkonce_odr_autohide are not supported
// and don't have to be, LLVM treats them as no-ops.
match name {
"appending" => Some(llvm::AppendingLinkage),
"available_externally" => Some(llvm::AvailableExternallyLinkage),
"common" => Some(llvm::CommonLinkage),
"extern_weak" => Some(llvm::ExternalWeakLinkage),
"external" => Some(llvm::ExternalLinkage),
"internal" => Some(llvm::InternalLinkage),
"linkonce" => Some(llvm::LinkOnceAnyLinkage),
"linkonce_odr" => Some(llvm::LinkOnceODRLinkage),
"private" => Some(llvm::PrivateLinkage),
"weak" => Some(llvm::WeakAnyLinkage),
"weak_odr" => Some(llvm::WeakODRLinkage),
_ => None,
}
}
/// Enum describing the origin of an LLVM `Value`, for linkage purposes.
#[derive(Copy, Clone)]
pub enum ValueOrigin {
/// The LLVM `Value` is in this context because the corresponding item was
/// assigned to the current compilation unit.
OriginalTranslation,
/// The `Value`'s corresponding item was assigned to some other compilation
/// unit, but the `Value` was translated in this context anyway because the
/// item is marked `#[inline]`.
InlinedCopy,
}
/// Set the appropriate linkage for an LLVM `ValueRef` (function or global).
/// If the `llval` is the direct translation of a specific Rust item, `id`
/// should be set to the `NodeId` of that item. (This mapping should be
/// 1-to-1, so monomorphizations and drop/visit glue should have `id` set to
/// `None`.) `llval_origin` indicates whether `llval` is the translation of an
/// item assigned to `ccx`'s compilation unit or an inlined copy of an item
/// assigned to a different compilation unit.
pub fn update_linkage(ccx: &CrateContext,
llval: ValueRef,
id: Option<ast::NodeId>,
llval_origin: ValueOrigin) {
match llval_origin {
InlinedCopy => {
// `llval` is a translation of an item defined in a separate
// compilation unit. This only makes sense if there are at least
// two compilation units.
assert!(ccx.sess().opts.cg.codegen_units > 1);
// `llval` is a copy of something defined elsewhere, so use
// `AvailableExternallyLinkage` to avoid duplicating code in the
// output.
llvm::SetLinkage(llval, llvm::AvailableExternallyLinkage);
return;
},
OriginalTranslation => {},
}
if let Some(id) = id {
let item = ccx.tcx().map.get(id);
if let hir_map::NodeItem(i) = item {
if let Some(name) = attr::first_attr_value_str_by_name(&i.attrs, "linkage") {
if let Some(linkage) = llvm_linkage_by_name(&name) {
llvm::SetLinkage(llval, linkage);
} else {
ccx.sess().span_fatal(i.span, "invalid linkage specified");
}
return;
}
}
}
match id {
Some(id) if ccx.reachable().contains(&id) => {
llvm::SetLinkage(llval, llvm::ExternalLinkage);
},
_ => {
// `id` does not refer to an item in `ccx.reachable`.
if ccx.sess().opts.cg.codegen_units > 1 {
llvm::SetLinkage(llval, llvm::ExternalLinkage);
} else {
llvm::SetLinkage(llval, llvm::InternalLinkage);
}
},
}
}
fn set_global_section(ccx: &CrateContext, llval: ValueRef, i: &hir::Item) {
match attr::first_attr_value_str_by_name(&i.attrs, "link_section") {
Some(sect) => {
if contains_null(&sect) {
ccx.sess().fatal(&format!("Illegal null byte in link_section value: `{}`", &sect));
}
unsafe {
let buf = CString::new(sect.as_bytes()).unwrap();
llvm::LLVMSetSection(llval, buf.as_ptr());
}
},
None => ()
}
}
pub fn trans_item(ccx: &CrateContext, item: &hir::Item) {
let _icx = push_ctxt("trans_item");
let from_external = ccx.external_srcs().borrow().contains_key(&item.id);
match item.node {
hir::ItemFn(ref decl, _, _, abi, ref generics, ref body) => {
if !generics.is_type_parameterized() {
let trans_everywhere = attr::requests_inline(&item.attrs);
// Ignore `trans_everywhere` for cross-crate inlined items
// (`from_external`). `trans_item` will be called once for each
// compilation unit that references the item, so it will still get
// translated everywhere it's needed.
for (ref ccx, is_origin) in ccx.maybe_iter(!from_external && trans_everywhere) {
let llfn = get_item_val(ccx, item.id);
let empty_substs = ccx.tcx().mk_substs(Substs::trans_empty());
if abi != Rust {
foreign::trans_rust_fn_with_foreign_abi(ccx,
&**decl,
&**body,
&item.attrs,
llfn,
empty_substs,
item.id,
None);
} else {
trans_fn(ccx,
&**decl,
&**body,
llfn,
empty_substs,
item.id,
&item.attrs);
}
set_global_section(ccx, llfn, item);
update_linkage(ccx,
llfn,
Some(item.id),
if is_origin {
OriginalTranslation
} else {
InlinedCopy
});
if is_entry_fn(ccx.sess(), item.id) {
create_entry_wrapper(ccx, item.span, llfn);
// check for the #[rustc_error] annotation, which forces an
// error in trans. This is used to write compile-fail tests
// that actually test that compilation succeeds without
// reporting an error.
let item_def_id = ccx.tcx().map.local_def_id(item.id);
if ccx.tcx().has_attr(item_def_id, "rustc_error") {
ccx.tcx().sess.span_fatal(item.span, "compilation successful");
}
}
}
}
}
hir::ItemImpl(_, _, ref generics, _, _, ref impl_items) => {
meth::trans_impl(ccx, item.name, impl_items, generics, item.id);
}
hir::ItemMod(_) => {
// modules have no equivalent at runtime, they just affect
// the mangled names of things contained within
}
hir::ItemEnum(ref enum_definition, ref gens) => {
if gens.ty_params.is_empty() {
// sizes only make sense for non-generic types
enum_variant_size_lint(ccx, enum_definition, item.span, item.id);
}
}
hir::ItemConst(..) => {}
hir::ItemStatic(_, m, ref expr) => {
let g = match consts::trans_static(ccx, m, expr, item.id, &item.attrs) {
Ok(g) => g,
Err(err) => ccx.tcx().sess.span_fatal(expr.span, &err.description()),
};
set_global_section(ccx, g, item);
update_linkage(ccx, g, Some(item.id), OriginalTranslation);
}
hir::ItemForeignMod(ref foreign_mod) => {
foreign::trans_foreign_mod(ccx, foreign_mod);
}
hir::ItemTrait(..) => {}
_ => {
// fall through
}
}
}
// only use this for foreign function ABIs and glue, use `register_fn` for Rust functions
pub fn register_fn_llvmty(ccx: &CrateContext,
sp: Span,
sym: String,
node_id: ast::NodeId,
cc: llvm::CallConv,
llfty: Type)
-> ValueRef {
debug!("register_fn_llvmty id={} sym={}", node_id, sym);
let llfn = declare::define_fn(ccx, &sym[..], cc, llfty,
ty::FnConverging(ccx.tcx().mk_nil())).unwrap_or_else(||{
ccx.sess().span_fatal(sp, &format!("symbol `{}` is already defined", sym));
});
finish_register_fn(ccx, sym, node_id);
llfn
}
fn finish_register_fn(ccx: &CrateContext, sym: String, node_id: ast::NodeId) {
ccx.item_symbols().borrow_mut().insert(node_id, sym);
}
fn register_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
sp: Span,
sym: String,
node_id: ast::NodeId,
node_type: Ty<'tcx>)
-> ValueRef {
if let ty::TyBareFn(_, ref f) = node_type.sty {
if f.abi != Rust && f.abi != RustCall {
ccx.sess().span_bug(sp,
&format!("only the `{}` or `{}` calling conventions are valid \
for this function; `{}` was specified",
Rust.name(),
RustCall.name(),
f.abi.name()));
}
} else {
ccx.sess().span_bug(sp, "expected bare rust function")
}
let llfn = declare::define_rust_fn(ccx, &sym[..], node_type).unwrap_or_else(|| {
ccx.sess().span_fatal(sp, &format!("symbol `{}` is already defined", sym));
});
finish_register_fn(ccx, sym, node_id);
llfn
}
pub fn is_entry_fn(sess: &Session, node_id: ast::NodeId) -> bool {
match *sess.entry_fn.borrow() {
Some((entry_id, _)) => node_id == entry_id,
None => false,
}
}
/// Create the `main` function which will initialise the rust runtime and call users’ main
/// function.
pub fn create_entry_wrapper(ccx: &CrateContext, sp: Span, main_llfn: ValueRef) {
let et = ccx.sess().entry_type.get().unwrap();
match et {
config::EntryMain => {
create_entry_fn(ccx, sp, main_llfn, true);
}
config::EntryStart => create_entry_fn(ccx, sp, main_llfn, false),
config::EntryNone => {} // Do nothing.
}
fn create_entry_fn(ccx: &CrateContext,
sp: Span,
rust_main: ValueRef,
use_start_lang_item: bool) {
let llfty = Type::func(&[ccx.int_type(), Type::i8p(ccx).ptr_to()], &ccx.int_type());
let llfn = declare::define_cfn(ccx, "main", llfty, ccx.tcx().mk_nil()).unwrap_or_else(|| {
// FIXME: We should be smart and show a better diagnostic here.
ccx.sess().struct_span_err(sp, "entry symbol `main` defined multiple times")
.help("did you use #[no_mangle] on `fn main`? Use #[start] instead")
.emit();
ccx.sess().abort_if_errors();
panic!();
});
let llbb = unsafe {
llvm::LLVMAppendBasicBlockInContext(ccx.llcx(), llfn, "top\0".as_ptr() as *const _)
};
let bld = ccx.raw_builder();
unsafe {
llvm::LLVMPositionBuilderAtEnd(bld, llbb);
debuginfo::gdb::insert_reference_to_gdb_debug_scripts_section_global(ccx);
let (start_fn, args) = if use_start_lang_item {
let start_def_id = match ccx.tcx().lang_items.require(StartFnLangItem) {
Ok(id) => id,
Err(s) => {
ccx.sess().fatal(&s[..]);
}
};
let start_fn = if let Some(start_node_id) = ccx.tcx()
.map
.as_local_node_id(start_def_id) {
get_item_val(ccx, start_node_id)
} else {
let start_fn_type = ccx.tcx().lookup_item_type(start_def_id).ty;
trans_external_path(ccx, start_def_id, start_fn_type)
};
let args = {
let opaque_rust_main =
llvm::LLVMBuildPointerCast(bld,
rust_main,
Type::i8p(ccx).to_ref(),
"rust_main\0".as_ptr() as *const _);
vec![opaque_rust_main, get_param(llfn, 0), get_param(llfn, 1)]
};
(start_fn, args)
} else {
debug!("using user-defined start fn");
let args = vec![get_param(llfn, 0 as c_uint), get_param(llfn, 1 as c_uint)];
(rust_main, args)
};
let result = llvm::LLVMBuildCall(bld,
start_fn,
args.as_ptr(),
args.len() as c_uint,
noname());
llvm::LLVMBuildRet(bld, result);
}
}
}
fn exported_name<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
id: ast::NodeId,
ty: Ty<'tcx>,
attrs: &[ast::Attribute])
-> String {
match ccx.external_srcs().borrow().get(&id) {
Some(&did) => {
let sym = ccx.sess().cstore.item_symbol(did);
debug!("found item {} in other crate...", sym);
return sym;
}
None => {}
}
match attr::find_export_name_attr(ccx.sess().diagnostic(), attrs) {
// Use provided name
Some(name) => name.to_string(),
_ => {
let path = ccx.tcx().map.def_path_from_id(id);
if attr::contains_name(attrs, "no_mangle") {
// Don't mangle
path.last().unwrap().data.to_string()
} else {
match weak_lang_items::link_name(attrs) {
Some(name) => name.to_string(),
None => {
// Usual name mangling
mangle_exported_name(ccx, path, ty, id)
}
}
}
}
}
}
fn contains_null(s: &str) -> bool {
s.bytes().any(|b| b == 0)
}
pub fn get_item_val(ccx: &CrateContext, id: ast::NodeId) -> ValueRef {
debug!("get_item_val(id=`{}`)", id);
match ccx.item_vals().borrow().get(&id).cloned() {
Some(v) => return v,
None => {}
}
let item = ccx.tcx().map.get(id);
debug!("get_item_val: id={} item={:?}", id, item);
let val = match item {
hir_map::NodeItem(i) => {
let ty = ccx.tcx().node_id_to_type(i.id);
let sym = || exported_name(ccx, id, ty, &i.attrs);
let v = match i.node {
hir::ItemStatic(..) => {
// If this static came from an external crate, then
// we need to get the symbol from metadata instead of
// using the current crate's name/version
// information in the hash of the symbol
let sym = sym();
debug!("making {}", sym);
// Create the global before evaluating the initializer;
// this is necessary to allow recursive statics.
let llty = type_of(ccx, ty);
let g = declare::define_global(ccx, &sym[..], llty).unwrap_or_else(|| {
ccx.sess()
.span_fatal(i.span, &format!("symbol `{}` is already defined", sym))
});
ccx.item_symbols().borrow_mut().insert(i.id, sym);
g
}
hir::ItemFn(_, _, _, abi, _, _) => {
let sym = sym();
let llfn = if abi == Rust {
register_fn(ccx, i.span, sym, i.id, ty)
} else {
foreign::register_rust_fn_with_foreign_abi(ccx, i.span, sym, i.id)
};
attributes::from_fn_attrs(ccx, &i.attrs, llfn);
llfn
}
_ => ccx.sess().bug("get_item_val: weird result in table"),
};
v
}
hir_map::NodeTraitItem(trait_item) => {
debug!("get_item_val(): processing a NodeTraitItem");
match trait_item.node {
hir::MethodTraitItem(_, Some(_)) => {
register_method(ccx, id, &trait_item.attrs, trait_item.span)
}
_ => {
ccx.sess().span_bug(trait_item.span,
"unexpected variant: trait item other than a provided \
method in get_item_val()");
}
}
}
hir_map::NodeImplItem(impl_item) => {
match impl_item.node {
hir::ImplItemKind::Method(..) => {
register_method(ccx, id, &impl_item.attrs, impl_item.span)
}
_ => {
ccx.sess().span_bug(impl_item.span,
"unexpected variant: non-method impl item in \
get_item_val()");
}
}
}
hir_map::NodeForeignItem(ni) => {
match ni.node {
hir::ForeignItemFn(..) => {
let abi = ccx.tcx().map.get_foreign_abi(id);
let ty = ccx.tcx().node_id_to_type(ni.id);
let name = foreign::link_name(&*ni);
foreign::register_foreign_item_fn(ccx, abi, ty, &name, &ni.attrs)
}
hir::ForeignItemStatic(..) => {
foreign::register_static(ccx, &*ni)
}
}
}
hir_map::NodeVariant(ref v) => {
let llfn;
let fields = if v.node.data.is_struct() {
ccx.sess().bug("struct variant kind unexpected in get_item_val")
} else {
v.node.data.fields()
};
assert!(!fields.is_empty());
let ty = ccx.tcx().node_id_to_type(id);
let parent = ccx.tcx().map.get_parent(id);
let enm = ccx.tcx().map.expect_item(parent);
let sym = exported_name(ccx, id, ty, &enm.attrs);
llfn = match enm.node {
hir::ItemEnum(_, _) => {
register_fn(ccx, (*v).span, sym, id, ty)
}
_ => ccx.sess().bug("NodeVariant, shouldn't happen"),
};
attributes::inline(llfn, attributes::InlineAttr::Hint);
llfn
}
hir_map::NodeStructCtor(struct_def) => {
// Only register the constructor if this is a tuple-like struct.
let ctor_id = if struct_def.is_struct() {
ccx.sess().bug("attempt to register a constructor of a non-tuple-like struct")
} else {
struct_def.id()
};
let parent = ccx.tcx().map.get_parent(id);
let struct_item = ccx.tcx().map.expect_item(parent);
let ty = ccx.tcx().node_id_to_type(ctor_id);
let sym = exported_name(ccx, id, ty, &struct_item.attrs);
let llfn = register_fn(ccx, struct_item.span, sym, ctor_id, ty);
attributes::inline(llfn, attributes::InlineAttr::Hint);
llfn
}
ref variant => {
ccx.sess().bug(&format!("get_item_val(): unexpected variant: {:?}", variant))
}
};
// All LLVM globals and functions are initially created as external-linkage
// declarations. If `trans_item`/`trans_fn` later turns the declaration
// into a definition, it adjusts the linkage then (using `update_linkage`).
//
// The exception is foreign items, which have their linkage set inside the
// call to `foreign::register_*` above. We don't touch the linkage after
// that (`foreign::trans_foreign_mod` doesn't adjust the linkage like the
// other item translation functions do).
ccx.item_vals().borrow_mut().insert(id, val);
val
}
fn register_method(ccx: &CrateContext,
id: ast::NodeId,
attrs: &[ast::Attribute],
span: Span)
-> ValueRef {
let mty = ccx.tcx().node_id_to_type(id);
let sym = exported_name(ccx, id, mty, &attrs);
if let ty::TyBareFn(_, ref f) = mty.sty {
let llfn = if f.abi == Rust || f.abi == RustCall {
register_fn(ccx, span, sym, id, mty)
} else {
foreign::register_rust_fn_with_foreign_abi(ccx, span, sym, id)
};
attributes::from_fn_attrs(ccx, &attrs, llfn);
return llfn;
} else {
ccx.sess().span_bug(span, "expected bare rust function");
}
}
pub fn write_metadata<'a, 'tcx>(cx: &SharedCrateContext<'a, 'tcx>,
krate: &hir::Crate,
reachable: &NodeSet,
mir_map: &MirMap<'tcx>)
-> Vec<u8> {
use flate;
let any_library = cx.sess()
.crate_types
.borrow()
.iter()
.any(|ty| *ty != config::CrateTypeExecutable);
if !any_library {
return Vec::new();
}
let cstore = &cx.tcx().sess.cstore;
let metadata = cstore.encode_metadata(cx.tcx(),
cx.export_map(),
cx.item_symbols(),
cx.link_meta(),
reachable,
mir_map,
krate);
let mut compressed = cstore.metadata_encoding_version().to_vec();
compressed.extend_from_slice(&flate::deflate_bytes(&metadata));
let llmeta = C_bytes_in_context(cx.metadata_llcx(), &compressed[..]);
let llconst = C_struct_in_context(cx.metadata_llcx(), &[llmeta], false);
let name = format!("rust_metadata_{}_{}",
cx.link_meta().crate_name,
cx.link_meta().crate_hash);
let buf = CString::new(name).unwrap();
let llglobal = unsafe {
llvm::LLVMAddGlobal(cx.metadata_llmod(), val_ty(llconst).to_ref(), buf.as_ptr())
};
unsafe {
llvm::LLVMSetInitializer(llglobal, llconst);
let name =
cx.tcx().sess.cstore.metadata_section_name(&cx.sess().target.target);
let name = CString::new(name).unwrap();
llvm::LLVMSetSection(llglobal, name.as_ptr())
}
return metadata;
}
/// Find any symbols that are defined in one compilation unit, but not declared
/// in any other compilation unit. Give these symbols internal linkage.
fn internalize_symbols(cx: &SharedCrateContext, reachable: &HashSet<&str>) {
unsafe {
let mut declared = HashSet::new();
// Collect all external declarations in all compilation units.
for ccx in cx.iter() {
for val in iter_globals(ccx.llmod()).chain(iter_functions(ccx.llmod())) {
let linkage = llvm::LLVMGetLinkage(val);
// We only care about external declarations (not definitions)
// and available_externally definitions.
if !(linkage == llvm::ExternalLinkage as c_uint &&
llvm::LLVMIsDeclaration(val) != 0) &&
!(linkage == llvm::AvailableExternallyLinkage as c_uint) {
continue;
}
let name = CStr::from_ptr(llvm::LLVMGetValueName(val))
.to_bytes()
.to_vec();
declared.insert(name);
}
}
// Examine each external definition. If the definition is not used in
// any other compilation unit, and is not reachable from other crates,
// then give it internal linkage.
for ccx in cx.iter() {
for val in iter_globals(ccx.llmod()).chain(iter_functions(ccx.llmod())) {
// We only care about external definitions.
if !(llvm::LLVMGetLinkage(val) == llvm::ExternalLinkage as c_uint &&
llvm::LLVMIsDeclaration(val) == 0) {
continue;
}
let name = CStr::from_ptr(llvm::LLVMGetValueName(val))
.to_bytes()
.to_vec();
if !declared.contains(&name) &&
!reachable.contains(str::from_utf8(&name).unwrap()) {
llvm::SetLinkage(val, llvm::InternalLinkage);
llvm::SetDLLStorageClass(val, llvm::DefaultStorageClass);
}
}
}
}
}
// Create a `__imp_<symbol> = &symbol` global for every public static `symbol`.
// This is required to satisfy `dllimport` references to static data in .rlibs
// when using MSVC linker. We do this only for data, as linker can fix up
// code references on its own.
// See #26591, #27438
fn create_imps(cx: &SharedCrateContext) {
// The x86 ABI seems to require that leading underscores are added to symbol
// names, so we need an extra underscore on 32-bit. There's also a leading
// '\x01' here which disables LLVM's symbol mangling (e.g. no extra
// underscores added in front).
let prefix = if cx.sess().target.target.target_pointer_width == "32" {
"\x01__imp__"
} else {
"\x01__imp_"
};
unsafe {
for ccx in cx.iter() {
let exported: Vec<_> = iter_globals(ccx.llmod())
.filter(|&val| {
llvm::LLVMGetLinkage(val) ==
llvm::ExternalLinkage as c_uint &&
llvm::LLVMIsDeclaration(val) == 0
})
.collect();
let i8p_ty = Type::i8p(&ccx);
for val in exported {
let name = CStr::from_ptr(llvm::LLVMGetValueName(val));
let mut imp_name = prefix.as_bytes().to_vec();
imp_name.extend(name.to_bytes());
let imp_name = CString::new(imp_name).unwrap();
let imp = llvm::LLVMAddGlobal(ccx.llmod(),
i8p_ty.to_ref(),
imp_name.as_ptr() as *const _);
let init = llvm::LLVMConstBitCast(val, i8p_ty.to_ref());
llvm::LLVMSetInitializer(imp, init);
llvm::SetLinkage(imp, llvm::ExternalLinkage);
}
}
}
}
struct ValueIter {
cur: ValueRef,
step: unsafe extern "C" fn(ValueRef) -> ValueRef,
}
impl Iterator for ValueIter {
type Item = ValueRef;
fn next(&mut self) -> Option<ValueRef> {
let old = self.cur;
if !old.is_null() {
self.cur = unsafe { (self.step)(old) };
Some(old)
} else {
None
}
}
}
fn iter_globals(llmod: llvm::ModuleRef) -> ValueIter {
unsafe {
ValueIter {
cur: llvm::LLVMGetFirstGlobal(llmod),
step: llvm::LLVMGetNextGlobal,
}
}
}
fn iter_functions(llmod: llvm::ModuleRef) -> ValueIter {
unsafe {
ValueIter {
cur: llvm::LLVMGetFirstFunction(llmod),
step: llvm::LLVMGetNextFunction,
}
}
}
/// The context provided lists a set of reachable ids as calculated by
/// middle::reachable, but this contains far more ids and symbols than we're
/// actually exposing from the object file. This function will filter the set in
/// the context to the set of ids which correspond to symbols that are exposed
/// from the object file being generated.
///
/// This list is later used by linkers to determine the set of symbols needed to
/// be exposed from a dynamic library and it's also encoded into the metadata.
pub fn filter_reachable_ids(ccx: &SharedCrateContext) -> NodeSet {
ccx.reachable().iter().map(|x| *x).filter(|id| {
// First, only worry about nodes which have a symbol name
ccx.item_symbols().borrow().contains_key(id)
}).filter(|&id| {
// Next, we want to ignore some FFI functions that are not exposed from
// this crate. Reachable FFI functions can be lumped into two
// categories:
//
// 1. Those that are included statically via a static library
// 2. Those included otherwise (e.g. dynamically or via a framework)
//
// Although our LLVM module is not literally emitting code for the
// statically included symbols, it's an export of our library which
// needs to be passed on to the linker and encoded in the metadata.
//
// As a result, if this id is an FFI item (foreign item) then we only
// let it through if it's included statically.
match ccx.tcx().map.get(id) {
hir_map::NodeForeignItem(..) => {
ccx.sess().cstore.is_statically_included_foreign_item(id)
}
_ => true,
}
}).collect()
}
pub fn trans_crate<'tcx>(tcx: &ty::ctxt<'tcx>,
mir_map: &MirMap<'tcx>,
analysis: ty::CrateAnalysis)
-> CrateTranslation {
let _task = tcx.dep_graph.in_task(DepNode::TransCrate);
// Be careful with this krate: obviously it gives access to the
// entire contents of the krate. So if you push any subtasks of
// `TransCrate`, you need to be careful to register "reads" of the
// particular items that will be processed.
let krate = tcx.map.krate();
let ty::CrateAnalysis { export_map, reachable, name, .. } = analysis;
let check_overflow = if let Some(v) = tcx.sess.opts.debugging_opts.force_overflow_checks {
v
} else {
tcx.sess.opts.debug_assertions
};
let check_dropflag = if let Some(v) = tcx.sess.opts.debugging_opts.force_dropflag_checks {
v
} else {
tcx.sess.opts.debug_assertions
};
// Before we touch LLVM, make sure that multithreading is enabled.
unsafe {
use std::sync::Once;
static INIT: Once = Once::new();
static mut POISONED: bool = false;
INIT.call_once(|| {
if llvm::LLVMStartMultithreaded() != 1 {
// use an extra bool to make sure that all future usage of LLVM
// cannot proceed despite the Once not running more than once.
POISONED = true;
}
::back::write::configure_llvm(&tcx.sess);
});
if POISONED {
tcx.sess.bug("couldn't enable multi-threaded LLVM");
}
}
let link_meta = link::build_link_meta(&tcx.sess, krate, name);
let codegen_units = tcx.sess.opts.cg.codegen_units;
let shared_ccx = SharedCrateContext::new(&link_meta.crate_name,
codegen_units,
tcx,
&mir_map,
export_map,
Sha256::new(),
link_meta.clone(),
reachable,
check_overflow,
check_dropflag);
{
let ccx = shared_ccx.get_ccx(0);
// First, verify intrinsics.
intrinsic::check_intrinsics(&ccx);
// Next, translate all items. See `TransModVisitor` for
// details on why we walk in this particular way.
{
let _icx = push_ctxt("text");
intravisit::walk_mod(&mut TransItemsWithinModVisitor { ccx: &ccx }, &krate.module);
krate.visit_all_items(&mut TransModVisitor { ccx: &ccx });
}
}
for ccx in shared_ccx.iter() {
if ccx.sess().opts.debuginfo != NoDebugInfo {
debuginfo::finalize(&ccx);
}
for &(old_g, new_g) in ccx.statics_to_rauw().borrow().iter() {
unsafe {
let bitcast = llvm::LLVMConstPointerCast(new_g, llvm::LLVMTypeOf(old_g));
llvm::LLVMReplaceAllUsesWith(old_g, bitcast);
llvm::LLVMDeleteGlobal(old_g);
}
}
}
let reachable_symbol_ids = filter_reachable_ids(&shared_ccx);
// Translate the metadata.
let metadata = time(tcx.sess.time_passes(), "write metadata", || {
write_metadata(&shared_ccx, krate, &reachable_symbol_ids, mir_map)
});
if shared_ccx.sess().trans_stats() {
let stats = shared_ccx.stats();
println!("--- trans stats ---");
println!("n_glues_created: {}", stats.n_glues_created.get());
println!("n_null_glues: {}", stats.n_null_glues.get());
println!("n_real_glues: {}", stats.n_real_glues.get());
println!("n_fns: {}", stats.n_fns.get());
println!("n_monos: {}", stats.n_monos.get());
println!("n_inlines: {}", stats.n_inlines.get());
println!("n_closures: {}", stats.n_closures.get());
println!("fn stats:");
stats.fn_stats.borrow_mut().sort_by(|&(_, insns_a), &(_, insns_b)| {
insns_b.cmp(&insns_a)
});
for tuple in stats.fn_stats.borrow().iter() {
match *tuple {
(ref name, insns) => {
println!("{} insns, {}", insns, *name);
}
}
}
}
if shared_ccx.sess().count_llvm_insns() {
for (k, v) in shared_ccx.stats().llvm_insns.borrow().iter() {
println!("{:7} {}", *v, *k);
}
}
let modules = shared_ccx.iter()
.map(|ccx| ModuleTranslation { llcx: ccx.llcx(), llmod: ccx.llmod() })
.collect();
let sess = shared_ccx.sess();
let mut reachable_symbols = reachable_symbol_ids.iter().map(|id| {
shared_ccx.item_symbols().borrow()[id].to_string()
}).collect::<Vec<_>>();
if sess.entry_fn.borrow().is_some() {
reachable_symbols.push("main".to_string());
}
// For the purposes of LTO, we add to the reachable set all of the upstream
// reachable extern fns. These functions are all part of the public ABI of
// the final product, so LTO needs to preserve them.
if sess.lto() {
for cnum in sess.cstore.crates() {
let syms = sess.cstore.reachable_ids(cnum);
reachable_symbols.extend(syms.into_iter().filter(|did| {
sess.cstore.is_extern_fn(shared_ccx.tcx(), *did) ||
sess.cstore.is_static(*did)
}).map(|did| {
sess.cstore.item_symbol(did)
}));
}
}
if codegen_units > 1 {
internalize_symbols(&shared_ccx,
&reachable_symbols.iter().map(|x| &x[..]).collect());
}
if sess.target.target.options.is_like_msvc &&
sess.crate_types.borrow().iter().any(|ct| *ct == config::CrateTypeRlib) {
create_imps(&shared_ccx);
}
let metadata_module = ModuleTranslation {
llcx: shared_ccx.metadata_llcx(),
llmod: shared_ccx.metadata_llmod(),
};
let no_builtins = attr::contains_name(&krate.attrs, "no_builtins");
assert_dep_graph::assert_dep_graph(tcx);
CrateTranslation {
modules: modules,
metadata_module: metadata_module,
link: link_meta,
metadata: metadata,
reachable: reachable_symbols,
no_builtins: no_builtins,
}
}
/// We visit all the items in the krate and translate them. We do
/// this in two walks. The first walk just finds module items. It then
/// walks the full contents of those module items and translates all
/// the items within. Note that this entire process is O(n). The
/// reason for this two phased walk is that each module is
/// (potentially) placed into a distinct codegen-unit. This walk also
/// ensures that the immediate contents of each module is processed
/// entirely before we proceed to find more modules, helping to ensure
/// an equitable distribution amongst codegen-units.
pub struct TransModVisitor<'a, 'tcx: 'a> {
pub ccx: &'a CrateContext<'a, 'tcx>,
}
impl<'a, 'tcx, 'v> Visitor<'v> for TransModVisitor<'a, 'tcx> {
fn visit_item(&mut self, i: &hir::Item) {
match i.node {
hir::ItemMod(_) => {
let item_ccx = self.ccx.rotate();
intravisit::walk_item(&mut TransItemsWithinModVisitor { ccx: &item_ccx }, i);
}
_ => { }
}
}
}
/// Translates all the items within a given module. Expects owner to
/// invoke `walk_item` on a module item. Ignores nested modules.
pub struct TransItemsWithinModVisitor<'a, 'tcx: 'a> {
pub ccx: &'a CrateContext<'a, 'tcx>,
}
impl<'a, 'tcx, 'v> Visitor<'v> for TransItemsWithinModVisitor<'a, 'tcx> {
fn visit_nested_item(&mut self, item_id: hir::ItemId) {
self.visit_item(self.ccx.tcx().map.expect_item(item_id.id));
}
fn visit_item(&mut self, i: &hir::Item) {
match i.node {
hir::ItemMod(..) => {
// skip modules, they will be uncovered by the TransModVisitor
}
_ => {
let def_id = self.ccx.tcx().map.local_def_id(i.id);
let tcx = self.ccx.tcx();
// Create a subtask for trans'ing a particular item. We are
// giving `trans_item` access to this item, so also record a read.
tcx.dep_graph.with_task(DepNode::TransCrateItem(def_id), || {
tcx.dep_graph.read(DepNode::Hir(def_id));
trans_item(self.ccx, i);
});
intravisit::walk_item(self, i);
}
}
}
}