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fuchsia / third_party / rust / e804a3cf256106c097d44f6e0212cd183122da07 / . / src / librustc_trans / expr.rs
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// Copyright 2012-2014 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.
//! # Translation of Expressions
//!
//! The expr module handles translation of expressions. The most general
//! translation routine is `trans()`, which will translate an expression
//! into a datum. `trans_into()` is also available, which will translate
//! an expression and write the result directly into memory, sometimes
//! avoiding the need for a temporary stack slot. Finally,
//! `trans_to_lvalue()` is available if you'd like to ensure that the
//! result has cleanup scheduled.
//!
//! Internally, each of these functions dispatches to various other
//! expression functions depending on the kind of expression. We divide
//! up expressions into:
//!
//! - **Datum expressions:** Those that most naturally yield values.
//! Examples would be `22`, `box x`, or `a + b` (when not overloaded).
//! - **DPS expressions:** Those that most naturally write into a location
//! in memory. Examples would be `foo()` or `Point { x: 3, y: 4 }`.
//! - **Statement expressions:** That that do not generate a meaningful
//! result. Examples would be `while { ... }` or `return 44`.
//!
//! Public entry points:
//!
//! - `trans_into(bcx, expr, dest) -> bcx`: evaluates an expression,
//! storing the result into `dest`. This is the preferred form, if you
//! can manage it.
//!
//! - `trans(bcx, expr) -> DatumBlock`: evaluates an expression, yielding
//! `Datum` with the result. You can then store the datum, inspect
//! the value, etc. This may introduce temporaries if the datum is a
//! structural type.
//!
//! - `trans_to_lvalue(bcx, expr, "...") -> DatumBlock`: evaluates an
//! expression and ensures that the result has a cleanup associated with it,
//! creating a temporary stack slot if necessary.
//!
//! - `trans_var -> Datum`: looks up a local variable, upvar or static.
#![allow(non_camel_case_types)]
pub use self::Dest::*;
use self::lazy_binop_ty::*;
use llvm::{self, ValueRef, TypeKind};
use middle::const_qualif::ConstQualif;
use rustc::hir::def::Def;
use rustc::ty::subst::Substs;
use {_match, abi, adt, asm, base, closure, consts, controlflow};
use base::*;
use build::*;
use callee::{Callee, ArgExprs, ArgOverloadedCall, ArgOverloadedOp};
use cleanup::{self, CleanupMethods, DropHintMethods};
use common::*;
use datum::*;
use debuginfo::{self, DebugLoc, ToDebugLoc};
use glue;
use machine;
use tvec;
use type_of;
use value::Value;
use Disr;
use rustc::ty::adjustment::{AdjustDerefRef, AdjustReifyFnPointer};
use rustc::ty::adjustment::{AdjustUnsafeFnPointer, AdjustMutToConstPointer};
use rustc::ty::adjustment::CustomCoerceUnsized;
use rustc::ty::{self, Ty, TyCtxt};
use rustc::ty::MethodCall;
use rustc::ty::cast::{CastKind, CastTy};
use util::common::indenter;
use machine::{llsize_of, llsize_of_alloc};
use type_::Type;
use rustc::hir;
use syntax::ast;
use syntax::parse::token::InternedString;
use syntax_pos;
use std::fmt;
use std::mem;
// Destinations
// These are passed around by the code generating functions to track the
// destination of a computation's value.
#[derive(Copy, Clone, PartialEq)]
pub enum Dest {
SaveIn(ValueRef),
Ignore,
}
impl fmt::Debug for Dest {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match *self {
SaveIn(v) => write!(f, "SaveIn({:?})", Value(v)),
Ignore => f.write_str("Ignore")
}
}
}
/// This function is equivalent to `trans(bcx, expr).store_to_dest(dest)` but it may generate
/// better optimized LLVM code.
pub fn trans_into<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
expr: &hir::Expr,
dest: Dest)
-> Block<'blk, 'tcx> {
let mut bcx = bcx;
expr.debug_loc().apply(bcx.fcx);
if adjustment_required(bcx, expr) {
// use trans, which may be less efficient but
// which will perform the adjustments:
let datum = unpack_datum!(bcx, trans(bcx, expr));
return datum.store_to_dest(bcx, dest, expr.id);
}
let qualif = *bcx.tcx().const_qualif_map.borrow().get(&expr.id).unwrap();
if !qualif.intersects(ConstQualif::NOT_CONST | ConstQualif::NEEDS_DROP) {
if !qualif.intersects(ConstQualif::PREFER_IN_PLACE) {
if let SaveIn(lldest) = dest {
match consts::get_const_expr_as_global(bcx.ccx(), expr, qualif,
bcx.fcx.param_substs,
consts::TrueConst::No) {
Ok(global) => {
// Cast pointer to destination, because constants
// have different types.
let lldest = PointerCast(bcx, lldest, val_ty(global));
memcpy_ty(bcx, lldest, global, expr_ty_adjusted(bcx, expr));
return bcx;
},
Err(consts::ConstEvalFailure::Runtime(_)) => {
// in case const evaluation errors, translate normally
// debug assertions catch the same errors
// see RFC 1229
},
Err(consts::ConstEvalFailure::Compiletime(_)) => {
return bcx;
},
}
}
// If we see a const here, that's because it evaluates to a type with zero size. We
// should be able to just discard it, since const expressions are guaranteed not to
// have side effects. This seems to be reached through tuple struct constructors being
// passed zero-size constants.
if let hir::ExprPath(..) = expr.node {
match bcx.tcx().expect_def(expr.id) {
Def::Const(_) | Def::AssociatedConst(_) => {
assert!(type_is_zero_size(bcx.ccx(), bcx.tcx().node_id_to_type(expr.id)));
return bcx;
}
_ => {}
}
}
// Even if we don't have a value to emit, and the expression
// doesn't have any side-effects, we still have to translate the
// body of any closures.
// FIXME: Find a better way of handling this case.
} else {
// The only way we're going to see a `const` at this point is if
// it prefers in-place instantiation, likely because it contains
// `[x; N]` somewhere within.
match expr.node {
hir::ExprPath(..) => {
match bcx.tcx().expect_def(expr.id) {
Def::Const(did) | Def::AssociatedConst(did) => {
let empty_substs = bcx.tcx().mk_substs(Substs::empty());
let const_expr = consts::get_const_expr(bcx.ccx(), did, expr,
empty_substs);
// Temporarily get cleanup scopes out of the way,
// as they require sub-expressions to be contained
// inside the current AST scope.
// These should record no cleanups anyways, `const`
// can't have destructors.
let scopes = mem::replace(&mut *bcx.fcx.scopes.borrow_mut(),
vec![]);
// Lock emitted debug locations to the location of
// the constant reference expression.
debuginfo::with_source_location_override(bcx.fcx,
expr.debug_loc(),
|| {
bcx = trans_into(bcx, const_expr, dest)
});
let scopes = mem::replace(&mut *bcx.fcx.scopes.borrow_mut(),
scopes);
assert!(scopes.is_empty());
return bcx;
}
_ => {}
}
}
_ => {}
}
}
}
debug!("trans_into() expr={:?}", expr);
let cleanup_debug_loc = debuginfo::get_cleanup_debug_loc_for_ast_node(bcx.ccx(),
expr.id,
expr.span,
false);
bcx.fcx.push_ast_cleanup_scope(cleanup_debug_loc);
let kind = expr_kind(bcx.tcx(), expr);
bcx = match kind {
ExprKind::Lvalue | ExprKind::RvalueDatum => {
trans_unadjusted(bcx, expr).store_to_dest(dest, expr.id)
}
ExprKind::RvalueDps => {
trans_rvalue_dps_unadjusted(bcx, expr, dest)
}
ExprKind::RvalueStmt => {
trans_rvalue_stmt_unadjusted(bcx, expr)
}
};
bcx.fcx.pop_and_trans_ast_cleanup_scope(bcx, expr.id)
}
/// Translates an expression, returning a datum (and new block) encapsulating the result. When
/// possible, it is preferred to use `trans_into`, as that may avoid creating a temporary on the
/// stack.
pub fn trans<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
expr: &hir::Expr)
-> DatumBlock<'blk, 'tcx, Expr> {
debug!("trans(expr={:?})", expr);
let mut bcx = bcx;
let fcx = bcx.fcx;
let qualif = *bcx.tcx().const_qualif_map.borrow().get(&expr.id).unwrap();
let adjusted_global = !qualif.intersects(ConstQualif::NON_STATIC_BORROWS);
let global = if !qualif.intersects(ConstQualif::NOT_CONST | ConstQualif::NEEDS_DROP) {
match consts::get_const_expr_as_global(bcx.ccx(), expr, qualif,
bcx.fcx.param_substs,
consts::TrueConst::No) {
Ok(global) => {
if qualif.intersects(ConstQualif::HAS_STATIC_BORROWS) {
// Is borrowed as 'static, must return lvalue.
// Cast pointer to global, because constants have different types.
let const_ty = expr_ty_adjusted(bcx, expr);
let llty = type_of::type_of(bcx.ccx(), const_ty);
let global = PointerCast(bcx, global, llty.ptr_to());
let datum = Datum::new(global, const_ty, Lvalue::new("expr::trans"));
return DatumBlock::new(bcx, datum.to_expr_datum());
}
// Otherwise, keep around and perform adjustments, if needed.
let const_ty = if adjusted_global {
expr_ty_adjusted(bcx, expr)
} else {
expr_ty(bcx, expr)
};
// This could use a better heuristic.
Some(if type_is_immediate(bcx.ccx(), const_ty) {
// Cast pointer to global, because constants have different types.
let llty = type_of::type_of(bcx.ccx(), const_ty);
let global = PointerCast(bcx, global, llty.ptr_to());
// Maybe just get the value directly, instead of loading it?
immediate_rvalue(load_ty(bcx, global, const_ty), const_ty)
} else {
let scratch = alloc_ty(bcx, const_ty, "const");
call_lifetime_start(bcx, scratch);
let lldest = if !const_ty.is_structural() {
// Cast pointer to slot, because constants have different types.
PointerCast(bcx, scratch, val_ty(global))
} else {
// In this case, memcpy_ty calls llvm.memcpy after casting both
// source and destination to i8*, so we don't need any casts.
scratch
};
memcpy_ty(bcx, lldest, global, const_ty);
Datum::new(scratch, const_ty, Rvalue::new(ByRef))
})
},
Err(consts::ConstEvalFailure::Runtime(_)) => {
// in case const evaluation errors, translate normally
// debug assertions catch the same errors
// see RFC 1229
None
},
Err(consts::ConstEvalFailure::Compiletime(_)) => {
// generate a dummy llvm value
let const_ty = expr_ty(bcx, expr);
let llty = type_of::type_of(bcx.ccx(), const_ty);
let dummy = C_undef(llty.ptr_to());
Some(Datum::new(dummy, const_ty, Rvalue::new(ByRef)))
},
}
} else {
None
};
let cleanup_debug_loc = debuginfo::get_cleanup_debug_loc_for_ast_node(bcx.ccx(),
expr.id,
expr.span,
false);
fcx.push_ast_cleanup_scope(cleanup_debug_loc);
let datum = match global {
Some(rvalue) => rvalue.to_expr_datum(),
None => unpack_datum!(bcx, trans_unadjusted(bcx, expr))
};
let datum = if adjusted_global {
datum // trans::consts already performed adjustments.
} else {
unpack_datum!(bcx, apply_adjustments(bcx, expr, datum))
};
bcx = fcx.pop_and_trans_ast_cleanup_scope(bcx, expr.id);
return DatumBlock::new(bcx, datum);
}
pub fn get_meta(bcx: Block, fat_ptr: ValueRef) -> ValueRef {
StructGEP(bcx, fat_ptr, abi::FAT_PTR_EXTRA)
}
pub fn get_dataptr(bcx: Block, fat_ptr: ValueRef) -> ValueRef {
StructGEP(bcx, fat_ptr, abi::FAT_PTR_ADDR)
}
pub fn copy_fat_ptr(bcx: Block, src_ptr: ValueRef, dst_ptr: ValueRef) {
Store(bcx, Load(bcx, get_dataptr(bcx, src_ptr)), get_dataptr(bcx, dst_ptr));
Store(bcx, Load(bcx, get_meta(bcx, src_ptr)), get_meta(bcx, dst_ptr));
}
fn adjustment_required<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
expr: &hir::Expr) -> bool {
let adjustment = match bcx.tcx().tables.borrow().adjustments.get(&expr.id).cloned() {
None => { return false; }
Some(adj) => adj
};
// Don't skip a conversion from Box<T> to &T, etc.
if bcx.tcx().is_overloaded_autoderef(expr.id, 0) {
return true;
}
match adjustment {
AdjustReifyFnPointer => true,
AdjustUnsafeFnPointer | AdjustMutToConstPointer => {
// purely a type-level thing
false
}
AdjustDerefRef(ref adj) => {
// We are a bit paranoid about adjustments and thus might have a re-
// borrow here which merely derefs and then refs again (it might have
// a different region or mutability, but we don't care here).
!(adj.autoderefs == 1 && adj.autoref.is_some() && adj.unsize.is_none())
}
}
}
/// Helper for trans that apply adjustments from `expr` to `datum`, which should be the unadjusted
/// translation of `expr`.
fn apply_adjustments<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
expr: &hir::Expr,
datum: Datum<'tcx, Expr>)
-> DatumBlock<'blk, 'tcx, Expr>
{
let mut bcx = bcx;
let mut datum = datum;
let adjustment = match bcx.tcx().tables.borrow().adjustments.get(&expr.id).cloned() {
None => {
return DatumBlock::new(bcx, datum);
}
Some(adj) => { adj }
};
debug!("unadjusted datum for expr {:?}: {:?} adjustment={:?}",
expr, datum, adjustment);
match adjustment {
AdjustReifyFnPointer => {
match datum.ty.sty {
ty::TyFnDef(def_id, substs, _) => {
datum = Callee::def(bcx.ccx(), def_id, substs)
.reify(bcx.ccx()).to_expr_datum();
}
_ => {
bug!("{} cannot be reified to a fn ptr", datum.ty)
}
}
}
AdjustUnsafeFnPointer | AdjustMutToConstPointer => {
// purely a type-level thing
}
AdjustDerefRef(ref adj) => {
let skip_reborrows = if adj.autoderefs == 1 && adj.autoref.is_some() {
// We are a bit paranoid about adjustments and thus might have a re-
// borrow here which merely derefs and then refs again (it might have
// a different region or mutability, but we don't care here).
match datum.ty.sty {
// Don't skip a conversion from Box<T> to &T, etc.
ty::TyRef(..) => {
if bcx.tcx().is_overloaded_autoderef(expr.id, 0) {
// Don't skip an overloaded deref.
0
} else {
1
}
}
_ => 0
}
} else {
0
};
if adj.autoderefs > skip_reborrows {
// Schedule cleanup.
let lval = unpack_datum!(bcx, datum.to_lvalue_datum(bcx, "auto_deref", expr.id));
datum = unpack_datum!(bcx, deref_multiple(bcx, expr,
lval.to_expr_datum(),
adj.autoderefs - skip_reborrows));
}
// (You might think there is a more elegant way to do this than a
// skip_reborrows bool, but then you remember that the borrow checker exists).
if skip_reborrows == 0 && adj.autoref.is_some() {
datum = unpack_datum!(bcx, auto_ref(bcx, datum, expr));
}
if let Some(target) = adj.unsize {
// We do not arrange cleanup ourselves; if we already are an
// L-value, then cleanup will have already been scheduled (and
// the `datum.to_rvalue_datum` call below will emit code to zero
// the drop flag when moving out of the L-value). If we are an
// R-value, then we do not need to schedule cleanup.
let source_datum = unpack_datum!(bcx,
datum.to_rvalue_datum(bcx, "__coerce_source"));
let target = bcx.monomorphize(&target);
let scratch = alloc_ty(bcx, target, "__coerce_target");
call_lifetime_start(bcx, scratch);
let target_datum = Datum::new(scratch, target,
Rvalue::new(ByRef));
bcx = coerce_unsized(bcx, expr.span, source_datum, target_datum);
datum = Datum::new(scratch, target,
RvalueExpr(Rvalue::new(ByRef)));
}
}
}
debug!("after adjustments, datum={:?}", datum);
DatumBlock::new(bcx, datum)
}
fn coerce_unsized<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
span: syntax_pos::Span,
source: Datum<'tcx, Rvalue>,
target: Datum<'tcx, Rvalue>)
-> Block<'blk, 'tcx> {
let mut bcx = bcx;
debug!("coerce_unsized({:?} -> {:?})", source, target);
match (&source.ty.sty, &target.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, .. })) => {
let (inner_source, inner_target) = (a, b);
let (base, old_info) = if !type_is_sized(bcx.tcx(), inner_source) {
// Normally, the source is a thin pointer and we are
// adding extra info to make a fat pointer. The exception
// is when we are upcasting an existing object fat pointer
// to use a different vtable. In that case, we want to
// load out the original data pointer so we can repackage
// it.
(Load(bcx, get_dataptr(bcx, source.val)),
Some(Load(bcx, get_meta(bcx, source.val))))
} else {
let val = if source.kind.is_by_ref() {
load_ty(bcx, source.val, source.ty)
} else {
source.val
};
(val, None)
};
let info = unsized_info(bcx.ccx(), inner_source, inner_target, old_info);
// Compute the base pointer. This doesn't change the pointer value,
// but merely its type.
let ptr_ty = type_of::in_memory_type_of(bcx.ccx(), inner_target).ptr_to();
let base = PointerCast(bcx, base, ptr_ty);
Store(bcx, base, get_dataptr(bcx, target.val));
Store(bcx, info, get_meta(bcx, target.val));
}
// This can be extended to enums and tuples in the future.
// (&ty::TyEnum(def_id_a, _), &ty::TyEnum(def_id_b, _)) |
(&ty::TyStruct(def_id_a, _), &ty::TyStruct(def_id_b, _)) => {
assert_eq!(def_id_a, def_id_b);
// The target is already by-ref because it's to be written to.
let source = unpack_datum!(bcx, source.to_ref_datum(bcx));
assert!(target.kind.is_by_ref());
let kind = custom_coerce_unsize_info(bcx.ccx().shared(),
source.ty,
target.ty);
let repr_source = adt::represent_type(bcx.ccx(), source.ty);
let src_fields = match &*repr_source {
&adt::Repr::Univariant(ref s, _) => &s.fields,
_ => span_bug!(span,
"Non univariant struct? (repr_source: {:?})",
repr_source),
};
let repr_target = adt::represent_type(bcx.ccx(), target.ty);
let target_fields = match &*repr_target {
&adt::Repr::Univariant(ref s, _) => &s.fields,
_ => span_bug!(span,
"Non univariant struct? (repr_target: {:?})",
repr_target),
};
let coerce_index = match kind {
CustomCoerceUnsized::Struct(i) => i
};
assert!(coerce_index < src_fields.len() && src_fields.len() == target_fields.len());
let source_val = adt::MaybeSizedValue::sized(source.val);
let target_val = adt::MaybeSizedValue::sized(target.val);
let iter = src_fields.iter().zip(target_fields).enumerate();
for (i, (src_ty, target_ty)) in iter {
let ll_source = adt::trans_field_ptr(bcx, &repr_source, source_val, Disr(0), i);
let ll_target = adt::trans_field_ptr(bcx, &repr_target, target_val, Disr(0), i);
// If this is the field we need to coerce, recurse on it.
if i == coerce_index {
coerce_unsized(bcx, span,
Datum::new(ll_source, src_ty,
Rvalue::new(ByRef)),
Datum::new(ll_target, target_ty,
Rvalue::new(ByRef)));
} else {
// Otherwise, simply copy the data from the source.
assert!(src_ty.is_phantom_data() || src_ty == target_ty);
memcpy_ty(bcx, ll_target, ll_source, src_ty);
}
}
}
_ => bug!("coerce_unsized: invalid coercion {:?} -> {:?}",
source.ty,
target.ty)
}
bcx
}
/// Translates an expression in "lvalue" mode -- meaning that it returns a reference to the memory
/// that the expr represents.
///
/// If this expression is an rvalue, this implies introducing a temporary. In other words,
/// something like `x().f` is translated into roughly the equivalent of
///
/// { tmp = x(); tmp.f }
pub fn trans_to_lvalue<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
expr: &hir::Expr,
name: &str)
-> DatumBlock<'blk, 'tcx, Lvalue> {
let mut bcx = bcx;
let datum = unpack_datum!(bcx, trans(bcx, expr));
return datum.to_lvalue_datum(bcx, name, expr.id);
}
/// A version of `trans` that ignores adjustments. You almost certainly do not want to call this
/// directly.
fn trans_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
expr: &hir::Expr)
-> DatumBlock<'blk, 'tcx, Expr> {
let mut bcx = bcx;
debug!("trans_unadjusted(expr={:?})", expr);
let _indenter = indenter();
expr.debug_loc().apply(bcx.fcx);
return match expr_kind(bcx.tcx(), expr) {
ExprKind::Lvalue | ExprKind::RvalueDatum => {
let datum = unpack_datum!(bcx, {
trans_datum_unadjusted(bcx, expr)
});
DatumBlock {bcx: bcx, datum: datum}
}
ExprKind::RvalueStmt => {
bcx = trans_rvalue_stmt_unadjusted(bcx, expr);
nil(bcx, expr_ty(bcx, expr))
}
ExprKind::RvalueDps => {
let ty = expr_ty(bcx, expr);
if type_is_zero_size(bcx.ccx(), ty) {
bcx = trans_rvalue_dps_unadjusted(bcx, expr, Ignore);
nil(bcx, ty)
} else {
let scratch = rvalue_scratch_datum(bcx, ty, "");
bcx = trans_rvalue_dps_unadjusted(
bcx, expr, SaveIn(scratch.val));
// Note: this is not obviously a good idea. It causes
// immediate values to be loaded immediately after a
// return from a call or other similar expression,
// which in turn leads to alloca's having shorter
// lifetimes and hence larger stack frames. However,
// in turn it can lead to more register pressure.
// Still, in practice it seems to increase
// performance, since we have fewer problems with
// morestack churn.
let scratch = unpack_datum!(
bcx, scratch.to_appropriate_datum(bcx));
DatumBlock::new(bcx, scratch.to_expr_datum())
}
}
};
fn nil<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, ty: Ty<'tcx>)
-> DatumBlock<'blk, 'tcx, Expr> {
let llval = C_undef(type_of::type_of(bcx.ccx(), ty));
let datum = immediate_rvalue(llval, ty);
DatumBlock::new(bcx, datum.to_expr_datum())
}
}
fn trans_datum_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
expr: &hir::Expr)
-> DatumBlock<'blk, 'tcx, Expr> {
let mut bcx = bcx;
let fcx = bcx.fcx;
let _icx = push_ctxt("trans_datum_unadjusted");
match expr.node {
hir::ExprType(ref e, _) => {
trans(bcx, &e)
}
hir::ExprPath(..) => {
let var = trans_var(bcx, bcx.tcx().expect_def(expr.id));
DatumBlock::new(bcx, var.to_expr_datum())
}
hir::ExprField(ref base, name) => {
trans_rec_field(bcx, &base, name.node)
}
hir::ExprTupField(ref base, idx) => {
trans_rec_tup_field(bcx, &base, idx.node)
}
hir::ExprIndex(ref base, ref idx) => {
trans_index(bcx, expr, &base, &idx, MethodCall::expr(expr.id))
}
hir::ExprBox(ref contents) => {
// Special case for `Box<T>`
let box_ty = expr_ty(bcx, expr);
let contents_ty = expr_ty(bcx, &contents);
match box_ty.sty {
ty::TyBox(..) => {
trans_uniq_expr(bcx, expr, box_ty, &contents, contents_ty)
}
_ => span_bug!(expr.span,
"expected unique box")
}
}
hir::ExprLit(ref lit) => trans_immediate_lit(bcx, expr, &lit),
hir::ExprBinary(op, ref lhs, ref rhs) => {
trans_binary(bcx, expr, op, &lhs, &rhs)
}
hir::ExprUnary(op, ref x) => {
trans_unary(bcx, expr, op, &x)
}
hir::ExprAddrOf(_, ref x) => {
match x.node {
hir::ExprRepeat(..) | hir::ExprVec(..) => {
// Special case for slices.
let cleanup_debug_loc =
debuginfo::get_cleanup_debug_loc_for_ast_node(bcx.ccx(),
x.id,
x.span,
false);
fcx.push_ast_cleanup_scope(cleanup_debug_loc);
let datum = unpack_datum!(
bcx, tvec::trans_slice_vec(bcx, expr, &x));
bcx = fcx.pop_and_trans_ast_cleanup_scope(bcx, x.id);
DatumBlock::new(bcx, datum)
}
_ => {
trans_addr_of(bcx, expr, &x)
}
}
}
hir::ExprCast(ref val, _) => {
// Datum output mode means this is a scalar cast:
trans_imm_cast(bcx, &val, expr.id)
}
_ => {
span_bug!(
expr.span,
"trans_rvalue_datum_unadjusted reached \
fall-through case: {:?}",
expr.node);
}
}
}
fn trans_field<'blk, 'tcx, F>(bcx: Block<'blk, 'tcx>,
base: &hir::Expr,
get_idx: F)
-> DatumBlock<'blk, 'tcx, Expr> where
F: FnOnce(TyCtxt<'blk, 'tcx, 'tcx>, &VariantInfo<'tcx>) -> usize,
{
let mut bcx = bcx;
let _icx = push_ctxt("trans_rec_field");
let base_datum = unpack_datum!(bcx, trans_to_lvalue(bcx, base, "field"));
let bare_ty = base_datum.ty;
let repr = adt::represent_type(bcx.ccx(), bare_ty);
let vinfo = VariantInfo::from_ty(bcx.tcx(), bare_ty, None);
let ix = get_idx(bcx.tcx(), &vinfo);
let d = base_datum.get_element(
bcx,
vinfo.fields[ix].1,
|srcval| {
adt::trans_field_ptr(bcx, &repr, srcval, vinfo.discr, ix)
});
if type_is_sized(bcx.tcx(), d.ty) {
DatumBlock { datum: d.to_expr_datum(), bcx: bcx }
} else {
let scratch = rvalue_scratch_datum(bcx, d.ty, "");
Store(bcx, d.val, get_dataptr(bcx, scratch.val));
let info = Load(bcx, get_meta(bcx, base_datum.val));
Store(bcx, info, get_meta(bcx, scratch.val));
// Always generate an lvalue datum, because this pointer doesn't own
// the data and cleanup is scheduled elsewhere.
DatumBlock::new(bcx, Datum::new(scratch.val, scratch.ty, LvalueExpr(d.kind)))
}
}
/// Translates `base.field`.
fn trans_rec_field<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
base: &hir::Expr,
field: ast::Name)
-> DatumBlock<'blk, 'tcx, Expr> {
trans_field(bcx, base, |_, vinfo| vinfo.field_index(field))
}
/// Translates `base.<idx>`.
fn trans_rec_tup_field<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
base: &hir::Expr,
idx: usize)
-> DatumBlock<'blk, 'tcx, Expr> {
trans_field(bcx, base, |_, _| idx)
}
fn trans_index<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
index_expr: &hir::Expr,
base: &hir::Expr,
idx: &hir::Expr,
method_call: MethodCall)
-> DatumBlock<'blk, 'tcx, Expr> {
//! Translates `base[idx]`.
let _icx = push_ctxt("trans_index");
let ccx = bcx.ccx();
let mut bcx = bcx;
let index_expr_debug_loc = index_expr.debug_loc();
// Check for overloaded index.
let method = ccx.tcx().tables.borrow().method_map.get(&method_call).cloned();
let elt_datum = match method {
Some(method) => {
let method_ty = monomorphize_type(bcx, method.ty);
let base_datum = unpack_datum!(bcx, trans(bcx, base));
// Translate index expression.
let ix_datum = unpack_datum!(bcx, trans(bcx, idx));
let ref_ty = // invoked methods have LB regions instantiated:
bcx.tcx().no_late_bound_regions(&method_ty.fn_ret()).unwrap().unwrap();
let elt_ty = match ref_ty.builtin_deref(true, ty::NoPreference) {
None => {
span_bug!(index_expr.span,
"index method didn't return a \
dereferenceable type?!")
}
Some(elt_tm) => elt_tm.ty,
};
// Overloaded. Invoke the index() method, which basically
// yields a `&T` pointer. We can then proceed down the
// normal path (below) to dereference that `&T`.
let scratch = rvalue_scratch_datum(bcx, ref_ty, "overloaded_index_elt");
bcx = Callee::method(bcx, method)
.call(bcx, index_expr_debug_loc,
ArgOverloadedOp(base_datum, Some(ix_datum)),
Some(SaveIn(scratch.val))).bcx;
let datum = scratch.to_expr_datum();
let lval = Lvalue::new("expr::trans_index overload");
if type_is_sized(bcx.tcx(), elt_ty) {
Datum::new(datum.to_llscalarish(bcx), elt_ty, LvalueExpr(lval))
} else {
Datum::new(datum.val, elt_ty, LvalueExpr(lval))
}
}
None => {
let base_datum = unpack_datum!(bcx, trans_to_lvalue(bcx,
base,
"index"));
// Translate index expression and cast to a suitable LLVM integer.
// Rust is less strict than LLVM in this regard.
let ix_datum = unpack_datum!(bcx, trans(bcx, idx));
let ix_val = ix_datum.to_llscalarish(bcx);
let ix_size = machine::llbitsize_of_real(bcx.ccx(),
val_ty(ix_val));
let int_size = machine::llbitsize_of_real(bcx.ccx(),
ccx.int_type());
let ix_val = {
if ix_size < int_size {
if expr_ty(bcx, idx).is_signed() {
SExt(bcx, ix_val, ccx.int_type())
} else { ZExt(bcx, ix_val, ccx.int_type()) }
} else if ix_size > int_size {
Trunc(bcx, ix_val, ccx.int_type())
} else {
ix_val
}
};
let unit_ty = base_datum.ty.sequence_element_type(bcx.tcx());
let (base, len) = base_datum.get_vec_base_and_len(bcx);
debug!("trans_index: base {:?}", Value(base));
debug!("trans_index: len {:?}", Value(len));
let bounds_check = ICmp(bcx,
llvm::IntUGE,
ix_val,
len,
index_expr_debug_loc);
let expect = ccx.get_intrinsic(&("llvm.expect.i1"));
let expected = Call(bcx,
expect,
&[bounds_check, C_bool(ccx, false)],
index_expr_debug_loc);
bcx = with_cond(bcx, expected, |bcx| {
controlflow::trans_fail_bounds_check(bcx,
expr_info(index_expr),
ix_val,
len)
});
let elt = InBoundsGEP(bcx, base, &[ix_val]);
let elt = PointerCast(bcx, elt, type_of::type_of(ccx, unit_ty).ptr_to());
let lval = Lvalue::new("expr::trans_index fallback");
Datum::new(elt, unit_ty, LvalueExpr(lval))
}
};
DatumBlock::new(bcx, elt_datum)
}
/// Translates a reference to a variable.
pub fn trans_var<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, def: Def)
-> Datum<'tcx, Lvalue> {
match def {
Def::Static(did, _) => consts::get_static(bcx.ccx(), did),
Def::Upvar(_, nid, _, _) => {
// Can't move upvars, so this is never a ZeroMemLastUse.
let local_ty = node_id_type(bcx, nid);
let lval = Lvalue::new_with_hint("expr::trans_var (upvar)",
bcx, nid, HintKind::ZeroAndMaintain);
match bcx.fcx.llupvars.borrow().get(&nid) {
Some(&val) => Datum::new(val, local_ty, lval),
None => {
bug!("trans_var: no llval for upvar {} found", nid);
}
}
}
Def::Local(_, nid) => {
let datum = match bcx.fcx.lllocals.borrow().get(&nid) {
Some(&v) => v,
None => {
bug!("trans_var: no datum for local/arg {} found", nid);
}
};
debug!("take_local(nid={}, v={:?}, ty={})",
nid, Value(datum.val), datum.ty);
datum
}
_ => bug!("{:?} should not reach expr::trans_var", def)
}
}
fn trans_rvalue_stmt_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
expr: &hir::Expr)
-> Block<'blk, 'tcx> {
let mut bcx = bcx;
let _icx = push_ctxt("trans_rvalue_stmt");
if bcx.unreachable.get() {
return bcx;
}
expr.debug_loc().apply(bcx.fcx);
match expr.node {
hir::ExprBreak(label_opt) => {
controlflow::trans_break(bcx, expr, label_opt.map(|l| l.node))
}
hir::ExprType(ref e, _) => {
trans_into(bcx, &e, Ignore)
}
hir::ExprAgain(label_opt) => {
controlflow::trans_cont(bcx, expr, label_opt.map(|l| l.node))
}
hir::ExprRet(ref ex) => {
// Check to see if the return expression itself is reachable.
// This can occur when the inner expression contains a return
let reachable = if let Some(ref cfg) = bcx.fcx.cfg {
cfg.node_is_reachable(expr.id)
} else {
true
};
if reachable {
controlflow::trans_ret(bcx, expr, ex.as_ref().map(|e| &**e))
} else {
// If it's not reachable, just translate the inner expression
// directly. This avoids having to manage a return slot when
// it won't actually be used anyway.
if let &Some(ref x) = ex {
bcx = trans_into(bcx, &x, Ignore);
}
// Mark the end of the block as unreachable. Once we get to
// a return expression, there's no more we should be doing
// after this.
Unreachable(bcx);
bcx
}
}
hir::ExprWhile(ref cond, ref body, _) => {
controlflow::trans_while(bcx, expr, &cond, &body)
}
hir::ExprLoop(ref body, _) => {
controlflow::trans_loop(bcx, expr, &body)
}
hir::ExprAssign(ref dst, ref src) => {
let src_datum = unpack_datum!(bcx, trans(bcx, &src));
let dst_datum = unpack_datum!(bcx, trans_to_lvalue(bcx, &dst, "assign"));
if bcx.fcx.type_needs_drop(dst_datum.ty) {
// If there are destructors involved, make sure we
// are copying from an rvalue, since that cannot possible
// alias an lvalue. We are concerned about code like:
//
// a = a
//
// but also
//
// a = a.b
//
// where e.g. a : Option<Foo> and a.b :
// Option<Foo>. In that case, freeing `a` before the
// assignment may also free `a.b`!
//
// We could avoid this intermediary with some analysis
// to determine whether `dst` may possibly own `src`.
expr.debug_loc().apply(bcx.fcx);
let src_datum = unpack_datum!(
bcx, src_datum.to_rvalue_datum(bcx, "ExprAssign"));
let opt_hint_datum = dst_datum.kind.drop_flag_info.hint_datum(bcx);
let opt_hint_val = opt_hint_datum.map(|d|d.to_value());
// 1. Drop the data at the destination, passing the
// drop-hint in case the lvalue has already been
// dropped or moved.
bcx = glue::drop_ty_core(bcx,
dst_datum.val,
dst_datum.ty,
expr.debug_loc(),
false,
opt_hint_val);
// 2. We are overwriting the destination; ensure that
// its drop-hint (if any) says "initialized."
if let Some(hint_val) = opt_hint_val {
let hint_llval = hint_val.value();
let drop_needed = C_u8(bcx.fcx.ccx, adt::DTOR_NEEDED_HINT);
Store(bcx, drop_needed, hint_llval);
}
src_datum.store_to(bcx, dst_datum.val)
} else {
src_datum.store_to(bcx, dst_datum.val)
}
}
hir::ExprAssignOp(op, ref dst, ref src) => {
let method = bcx.tcx().tables
.borrow()
.method_map
.get(&MethodCall::expr(expr.id)).cloned();
if let Some(method) = method {
let dst = unpack_datum!(bcx, trans(bcx, &dst));
let src_datum = unpack_datum!(bcx, trans(bcx, &src));
Callee::method(bcx, method)
.call(bcx, expr.debug_loc(),
ArgOverloadedOp(dst, Some(src_datum)), None).bcx
} else {
trans_assign_op(bcx, expr, op, &dst, &src)
}
}
hir::ExprInlineAsm(ref a, ref outputs, ref inputs) => {
let outputs = outputs.iter().map(|output| {
let out_datum = unpack_datum!(bcx, trans(bcx, output));
unpack_datum!(bcx, out_datum.to_lvalue_datum(bcx, "out", expr.id))
}).collect();
let inputs = inputs.iter().map(|input| {
let input = unpack_datum!(bcx, trans(bcx, input));
let input = unpack_datum!(bcx, input.to_rvalue_datum(bcx, "in"));
input.to_llscalarish(bcx)
}).collect();
asm::trans_inline_asm(bcx, a, outputs, inputs);
bcx
}
_ => {
span_bug!(
expr.span,
"trans_rvalue_stmt_unadjusted reached \
fall-through case: {:?}",
expr.node);
}
}
}
fn trans_rvalue_dps_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
expr: &hir::Expr,
dest: Dest)
-> Block<'blk, 'tcx> {
let _icx = push_ctxt("trans_rvalue_dps_unadjusted");
let mut bcx = bcx;
expr.debug_loc().apply(bcx.fcx);
// Entry into the method table if this is an overloaded call/op.
let method_call = MethodCall::expr(expr.id);
match expr.node {
hir::ExprType(ref e, _) => {
trans_into(bcx, &e, dest)
}
hir::ExprPath(..) => {
trans_def_dps_unadjusted(bcx, expr, bcx.tcx().expect_def(expr.id), dest)
}
hir::ExprIf(ref cond, ref thn, ref els) => {
controlflow::trans_if(bcx, expr.id, &cond, &thn, els.as_ref().map(|e| &**e), dest)
}
hir::ExprMatch(ref discr, ref arms, _) => {
_match::trans_match(bcx, expr, &discr, &arms[..], dest)
}
hir::ExprBlock(ref blk) => {
controlflow::trans_block(bcx, &blk, dest)
}
hir::ExprStruct(_, ref fields, ref base) => {
trans_struct(bcx,
&fields[..],
base.as_ref().map(|e| &**e),
expr.span,
expr.id,
node_id_type(bcx, expr.id),
dest)
}
hir::ExprTup(ref args) => {
let numbered_fields: Vec<(usize, &hir::Expr)> =
args.iter().enumerate().map(|(i, arg)| (i, &**arg)).collect();
trans_adt(bcx,
expr_ty(bcx, expr),
Disr(0),
&numbered_fields[..],
None,
dest,
expr.debug_loc())
}
hir::ExprLit(ref lit) => {
match lit.node {
ast::LitKind::Str(ref s, _) => {
tvec::trans_lit_str(bcx, expr, (*s).clone(), dest)
}
_ => {
span_bug!(expr.span,
"trans_rvalue_dps_unadjusted shouldn't be \
translating this type of literal")
}
}
}
hir::ExprVec(..) | hir::ExprRepeat(..) => {
tvec::trans_fixed_vstore(bcx, expr, dest)
}
hir::ExprClosure(_, ref decl, ref body, _) => {
let dest = match dest {
SaveIn(lldest) => closure::Dest::SaveIn(bcx, lldest),
Ignore => closure::Dest::Ignore(bcx.ccx())
};
// NB. To get the id of the closure, we don't use
// `local_def_id(id)`, but rather we extract the closure
// def-id from the expr's type. This is because this may
// be an inlined expression from another crate, and we
// want to get the ORIGINAL closure def-id, since that is
// the key we need to find the closure-kind and
// closure-type etc.
let (def_id, substs) = match expr_ty(bcx, expr).sty {
ty::TyClosure(def_id, substs) => (def_id, substs),
ref t =>
span_bug!(
expr.span,
"closure expr without closure type: {:?}", t),
};
closure::trans_closure_expr(dest,
decl,
body,
expr.id,
def_id,
substs).unwrap_or(bcx)
}
hir::ExprCall(ref f, ref args) => {
let method = bcx.tcx().tables.borrow().method_map.get(&method_call).cloned();
let (callee, args) = if let Some(method) = method {
let mut all_args = vec![&**f];
all_args.extend(args.iter().map(|e| &**e));
(Callee::method(bcx, method), ArgOverloadedCall(all_args))
} else {
let f = unpack_datum!(bcx, trans(bcx, f));
(match f.ty.sty {
ty::TyFnDef(def_id, substs, _) => {
Callee::def(bcx.ccx(), def_id, substs)
}
ty::TyFnPtr(_) => {
let f = unpack_datum!(bcx,
f.to_rvalue_datum(bcx, "callee"));
Callee::ptr(f)
}
_ => {
span_bug!(expr.span,
"type of callee is not a fn: {}", f.ty);
}
}, ArgExprs(&args))
};
callee.call(bcx, expr.debug_loc(), args, Some(dest)).bcx
}
hir::ExprMethodCall(_, _, ref args) => {
Callee::method_call(bcx, method_call)
.call(bcx, expr.debug_loc(), ArgExprs(&args), Some(dest)).bcx
}
hir::ExprBinary(op, ref lhs, ref rhs_expr) => {
// if not overloaded, would be RvalueDatumExpr
let lhs = unpack_datum!(bcx, trans(bcx, &lhs));
let mut rhs = unpack_datum!(bcx, trans(bcx, &rhs_expr));
if !op.node.is_by_value() {
rhs = unpack_datum!(bcx, auto_ref(bcx, rhs, rhs_expr));
}
Callee::method_call(bcx, method_call)
.call(bcx, expr.debug_loc(),
ArgOverloadedOp(lhs, Some(rhs)), Some(dest)).bcx
}
hir::ExprUnary(_, ref subexpr) => {
// if not overloaded, would be RvalueDatumExpr
let arg = unpack_datum!(bcx, trans(bcx, &subexpr));
Callee::method_call(bcx, method_call)
.call(bcx, expr.debug_loc(),
ArgOverloadedOp(arg, None), Some(dest)).bcx
}
hir::ExprCast(..) => {
// Trait casts used to come this way, now they should be coercions.
span_bug!(expr.span, "DPS expr_cast (residual trait cast?)")
}
hir::ExprAssignOp(op, _, _) => {
span_bug!(
expr.span,
"augmented assignment `{}=` should always be a rvalue_stmt",
op.node.as_str())
}
_ => {
span_bug!(
expr.span,
"trans_rvalue_dps_unadjusted reached fall-through \
case: {:?}",
expr.node);
}
}
}
fn trans_def_dps_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
ref_expr: &hir::Expr,
def: Def,
dest: Dest)
-> Block<'blk, 'tcx> {
let _icx = push_ctxt("trans_def_dps_unadjusted");
let lldest = match dest {
SaveIn(lldest) => lldest,
Ignore => { return bcx; }
};
let ty = expr_ty(bcx, ref_expr);
if let ty::TyFnDef(..) = ty.sty {
// Zero-sized function or ctor.
return bcx;
}
match def {
Def::Variant(tid, vid) => {
let variant = bcx.tcx().lookup_adt_def(tid).variant_with_id(vid);
// Nullary variant.
let ty = expr_ty(bcx, ref_expr);
let repr = adt::represent_type(bcx.ccx(), ty);
adt::trans_set_discr(bcx, &repr, lldest, Disr::from(variant.disr_val));
bcx
}
Def::Struct(..) => {
match ty.sty {
ty::TyStruct(def, _) if def.has_dtor() => {
let repr = adt::represent_type(bcx.ccx(), ty);
adt::trans_set_discr(bcx, &repr, lldest, Disr(0));
}
_ => {}
}
bcx
}
_ => {
span_bug!(ref_expr.span,
"Non-DPS def {:?} referened by {}",
def, bcx.node_id_to_string(ref_expr.id));
}
}
}
fn trans_struct<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
fields: &[hir::Field],
base: Option<&hir::Expr>,
expr_span: syntax_pos::Span,
expr_id: ast::NodeId,
ty: Ty<'tcx>,
dest: Dest) -> Block<'blk, 'tcx> {
let _icx = push_ctxt("trans_rec");
let tcx = bcx.tcx();
let vinfo = VariantInfo::of_node(tcx, ty, expr_id);
let mut need_base = vec![true; vinfo.fields.len()];
let numbered_fields = fields.iter().map(|field| {
let pos = vinfo.field_index(field.name.node);
need_base[pos] = false;
(pos, &*field.expr)
}).collect::<Vec<_>>();
let optbase = match base {
Some(base_expr) => {
let mut leftovers = Vec::new();
for (i, b) in need_base.iter().enumerate() {
if *b {
leftovers.push((i, vinfo.fields[i].1));
}
}
Some(StructBaseInfo {expr: base_expr,
fields: leftovers })
}
None => {
if need_base.iter().any(|b| *b) {
span_bug!(expr_span, "missing fields and no base expr")
}
None
}
};
trans_adt(bcx,
ty,
vinfo.discr,
&numbered_fields,
optbase,
dest,
DebugLoc::At(expr_id, expr_span))
}
/// Information that `trans_adt` needs in order to fill in the fields
/// of a struct copied from a base struct (e.g., from an expression
/// like `Foo { a: b, ..base }`.
///
/// Note that `fields` may be empty; the base expression must always be
/// evaluated for side-effects.
pub struct StructBaseInfo<'a, 'tcx> {
/// The base expression; will be evaluated after all explicit fields.
expr: &'a hir::Expr,
/// The indices of fields to copy paired with their types.
fields: Vec<(usize, Ty<'tcx>)>
}
/// Constructs an ADT instance:
///
/// - `fields` should be a list of field indices paired with the
/// expression to store into that field. The initializers will be
/// evaluated in the order specified by `fields`.
///
/// - `optbase` contains information on the base struct (if any) from
/// which remaining fields are copied; see comments on `StructBaseInfo`.
pub fn trans_adt<'a, 'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
ty: Ty<'tcx>,
discr: Disr,
fields: &[(usize, &hir::Expr)],
optbase: Option<StructBaseInfo<'a, 'tcx>>,
dest: Dest,
debug_location: DebugLoc)
-> Block<'blk, 'tcx> {
let _icx = push_ctxt("trans_adt");
let fcx = bcx.fcx;
let repr = adt::represent_type(bcx.ccx(), ty);
debug_location.apply(bcx.fcx);
// If we don't care about the result, just make a
// temporary stack slot
let addr = match dest {
SaveIn(pos) => pos,
Ignore => {
let llresult = alloc_ty(bcx, ty, "temp");
call_lifetime_start(bcx, llresult);
llresult
}
};
debug!("trans_adt");
// This scope holds intermediates that must be cleaned should
// panic occur before the ADT as a whole is ready.
let custom_cleanup_scope = fcx.push_custom_cleanup_scope();
if ty.is_simd() {
// Issue 23112: The original logic appeared vulnerable to same
// order-of-eval bug. But, SIMD values are tuple-structs;
// i.e. functional record update (FRU) syntax is unavailable.
//
// To be safe, double-check that we did not get here via FRU.
assert!(optbase.is_none());
// This is the constructor of a SIMD type, such types are
// always primitive machine types and so do not have a
// destructor or require any clean-up.
let llty = type_of::type_of(bcx.ccx(), ty);
// keep a vector as a register, and running through the field
// `insertelement`ing them directly into that register
// (i.e. avoid GEPi and `store`s to an alloca) .
let mut vec_val = C_undef(llty);
for &(i, ref e) in fields {
let block_datum = trans(bcx, &e);
bcx = block_datum.bcx;
let position = C_uint(bcx.ccx(), i);
let value = block_datum.datum.to_llscalarish(bcx);
vec_val = InsertElement(bcx, vec_val, value, position);
}
Store(bcx, vec_val, addr);
} else if let Some(base) = optbase {
// Issue 23112: If there is a base, then order-of-eval
// requires field expressions eval'ed before base expression.
// First, trans field expressions to temporary scratch values.
let scratch_vals: Vec<_> = fields.iter().map(|&(i, ref e)| {
let datum = unpack_datum!(bcx, trans(bcx, &e));
(i, datum)
}).collect();
debug_location.apply(bcx.fcx);
// Second, trans the base to the dest.
assert_eq!(discr, Disr(0));
let addr = adt::MaybeSizedValue::sized(addr);
match expr_kind(bcx.tcx(), &base.expr) {
ExprKind::RvalueDps | ExprKind::RvalueDatum if !bcx.fcx.type_needs_drop(ty) => {
bcx = trans_into(bcx, &base.expr, SaveIn(addr.value));
},
ExprKind::RvalueStmt => {
bug!("unexpected expr kind for struct base expr")
}
_ => {
let base_datum = unpack_datum!(bcx, trans_to_lvalue(bcx, &base.expr, "base"));
for &(i, t) in &base.fields {
let datum = base_datum.get_element(
bcx, t, |srcval| adt::trans_field_ptr(bcx, &repr, srcval, discr, i));
assert!(type_is_sized(bcx.tcx(), datum.ty));
let dest = adt::trans_field_ptr(bcx, &repr, addr, discr, i);
bcx = datum.store_to(bcx, dest);
}
}
}
// Finally, move scratch field values into actual field locations
for (i, datum) in scratch_vals {
let dest = adt::trans_field_ptr(bcx, &repr, addr, discr, i);
bcx = datum.store_to(bcx, dest);
}
} else {
// No base means we can write all fields directly in place.
let addr = adt::MaybeSizedValue::sized(addr);
for &(i, ref e) in fields {
let dest = adt::trans_field_ptr(bcx, &repr, addr, discr, i);
let e_ty = expr_ty_adjusted(bcx, &e);
bcx = trans_into(bcx, &e, SaveIn(dest));
let scope = cleanup::CustomScope(custom_cleanup_scope);
fcx.schedule_lifetime_end(scope, dest);
// FIXME: nonzeroing move should generalize to fields
fcx.schedule_drop_mem(scope, dest, e_ty, None);
}
}
adt::trans_set_discr(bcx, &repr, addr, discr);
fcx.pop_custom_cleanup_scope(custom_cleanup_scope);
// If we don't care about the result drop the temporary we made
match dest {
SaveIn(_) => bcx,
Ignore => {
bcx = glue::drop_ty(bcx, addr, ty, debug_location);
base::call_lifetime_end(bcx, addr);
bcx
}
}
}
fn trans_immediate_lit<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
expr: &hir::Expr,
lit: &ast::Lit)
-> DatumBlock<'blk, 'tcx, Expr> {
// must not be a string constant, that is a RvalueDpsExpr
let _icx = push_ctxt("trans_immediate_lit");
let ty = expr_ty(bcx, expr);
let v = consts::const_lit(bcx.ccx(), expr, lit);
immediate_rvalue_bcx(bcx, v, ty).to_expr_datumblock()
}
fn trans_unary<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
expr: &hir::Expr,
op: hir::UnOp,
sub_expr: &hir::Expr)
-> DatumBlock<'blk, 'tcx, Expr> {
let ccx = bcx.ccx();
let mut bcx = bcx;
let _icx = push_ctxt("trans_unary_datum");
let method_call = MethodCall::expr(expr.id);
// The only overloaded operator that is translated to a datum
// is an overloaded deref, since it is always yields a `&T`.
// Otherwise, we should be in the RvalueDpsExpr path.
assert!(op == hir::UnDeref || !ccx.tcx().is_method_call(expr.id));
let un_ty = expr_ty(bcx, expr);
let debug_loc = expr.debug_loc();
match op {
hir::UnNot => {
let datum = unpack_datum!(bcx, trans(bcx, sub_expr));
let llresult = Not(bcx, datum.to_llscalarish(bcx), debug_loc);
immediate_rvalue_bcx(bcx, llresult, un_ty).to_expr_datumblock()
}
hir::UnNeg => {
let datum = unpack_datum!(bcx, trans(bcx, sub_expr));
let val = datum.to_llscalarish(bcx);
let (bcx, llneg) = {
if un_ty.is_fp() {
let result = FNeg(bcx, val, debug_loc);
(bcx, result)
} else {
let is_signed = un_ty.is_signed();
let result = Neg(bcx, val, debug_loc);
let bcx = if bcx.ccx().check_overflow() && is_signed {
let (llty, min) = base::llty_and_min_for_signed_ty(bcx, un_ty);
let is_min = ICmp(bcx, llvm::IntEQ, val,
C_integral(llty, min, true), debug_loc);
with_cond(bcx, is_min, |bcx| {
let msg = InternedString::new(
"attempted to negate with overflow");
controlflow::trans_fail(bcx, expr_info(expr), msg)
})
} else {
bcx
};
(bcx, result)
}
};
immediate_rvalue_bcx(bcx, llneg, un_ty).to_expr_datumblock()
}
hir::UnDeref => {
let datum = unpack_datum!(bcx, trans(bcx, sub_expr));
deref_once(bcx, expr, datum, method_call)
}
}
}
fn trans_uniq_expr<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
box_expr: &hir::Expr,
box_ty: Ty<'tcx>,
contents: &hir::Expr,
contents_ty: Ty<'tcx>)
-> DatumBlock<'blk, 'tcx, Expr> {
let _icx = push_ctxt("trans_uniq_expr");
let fcx = bcx.fcx;
assert!(type_is_sized(bcx.tcx(), contents_ty));
let llty = type_of::type_of(bcx.ccx(), contents_ty);
let size = llsize_of(bcx.ccx(), llty);
let align = C_uint(bcx.ccx(), type_of::align_of(bcx.ccx(), contents_ty));
let llty_ptr = llty.ptr_to();
let Result { bcx, val } = malloc_raw_dyn(bcx,
llty_ptr,
box_ty,
size,
align,
box_expr.debug_loc());
// Unique boxes do not allocate for zero-size types. The standard library
// may assume that `free` is never called on the pointer returned for
// `Box<ZeroSizeType>`.
let bcx = if llsize_of_alloc(bcx.ccx(), llty) == 0 {
trans_into(bcx, contents, SaveIn(val))
} else {
let custom_cleanup_scope = fcx.push_custom_cleanup_scope();
fcx.schedule_free_value(cleanup::CustomScope(custom_cleanup_scope),
val, cleanup::HeapExchange, contents_ty);
let bcx = trans_into(bcx, contents, SaveIn(val));
fcx.pop_custom_cleanup_scope(custom_cleanup_scope);
bcx
};
immediate_rvalue_bcx(bcx, val, box_ty).to_expr_datumblock()
}
fn trans_addr_of<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
expr: &hir::Expr,
subexpr: &hir::Expr)
-> DatumBlock<'blk, 'tcx, Expr> {
let _icx = push_ctxt("trans_addr_of");
let mut bcx = bcx;
let sub_datum = unpack_datum!(bcx, trans_to_lvalue(bcx, subexpr, "addr_of"));
let ty = expr_ty(bcx, expr);
if !type_is_sized(bcx.tcx(), sub_datum.ty) {
// Always generate an lvalue datum, because this pointer doesn't own
// the data and cleanup is scheduled elsewhere.
DatumBlock::new(bcx, Datum::new(sub_datum.val, ty, LvalueExpr(sub_datum.kind)))
} else {
// Sized value, ref to a thin pointer
immediate_rvalue_bcx(bcx, sub_datum.val, ty).to_expr_datumblock()
}
}
fn trans_scalar_binop<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
binop_expr: &hir::Expr,
binop_ty: Ty<'tcx>,
op: hir::BinOp,
lhs: Datum<'tcx, Rvalue>,
rhs: Datum<'tcx, Rvalue>)
-> DatumBlock<'blk, 'tcx, Expr>
{
let _icx = push_ctxt("trans_scalar_binop");
let lhs_t = lhs.ty;
assert!(!lhs_t.is_simd());
let is_float = lhs_t.is_fp();
let is_signed = lhs_t.is_signed();
let info = expr_info(binop_expr);
let binop_debug_loc = binop_expr.debug_loc();
let mut bcx = bcx;
let lhs = lhs.to_llscalarish(bcx);
let rhs = rhs.to_llscalarish(bcx);
let val = match op.node {
hir::BiAdd => {
if is_float {
FAdd(bcx, lhs, rhs, binop_debug_loc)
} else {
let (newbcx, res) = with_overflow_check(
bcx, OverflowOp::Add, info, lhs_t, lhs, rhs, binop_debug_loc);
bcx = newbcx;
res
}
}
hir::BiSub => {
if is_float {
FSub(bcx, lhs, rhs, binop_debug_loc)
} else {
let (newbcx, res) = with_overflow_check(
bcx, OverflowOp::Sub, info, lhs_t, lhs, rhs, binop_debug_loc);
bcx = newbcx;
res
}
}
hir::BiMul => {
if is_float {
FMul(bcx, lhs, rhs, binop_debug_loc)
} else {
let (newbcx, res) = with_overflow_check(
bcx, OverflowOp::Mul, info, lhs_t, lhs, rhs, binop_debug_loc);
bcx = newbcx;
res
}
}
hir::BiDiv => {
if is_float {
FDiv(bcx, lhs, rhs, binop_debug_loc)
} else {
// Only zero-check integers; fp /0 is NaN
bcx = base::fail_if_zero_or_overflows(bcx,
expr_info(binop_expr),
op,
lhs,
rhs,
lhs_t);
if is_signed {
SDiv(bcx, lhs, rhs, binop_debug_loc)
} else {
UDiv(bcx, lhs, rhs, binop_debug_loc)
}
}
}
hir::BiRem => {
if is_float {
FRem(bcx, lhs, rhs, binop_debug_loc)
} else {
// Only zero-check integers; fp %0 is NaN
bcx = base::fail_if_zero_or_overflows(bcx,
expr_info(binop_expr),
op, lhs, rhs, lhs_t);
if is_signed {
SRem(bcx, lhs, rhs, binop_debug_loc)
} else {
URem(bcx, lhs, rhs, binop_debug_loc)
}
}
}
hir::BiBitOr => Or(bcx, lhs, rhs, binop_debug_loc),
hir::BiBitAnd => And(bcx, lhs, rhs, binop_debug_loc),
hir::BiBitXor => Xor(bcx, lhs, rhs, binop_debug_loc),
hir::BiShl => {
let (newbcx, res) = with_overflow_check(
bcx, OverflowOp::Shl, info, lhs_t, lhs, rhs, binop_debug_loc);
bcx = newbcx;
res
}
hir::BiShr => {
let (newbcx, res) = with_overflow_check(
bcx, OverflowOp::Shr, info, lhs_t, lhs, rhs, binop_debug_loc);
bcx = newbcx;
res
}
hir::BiEq | hir::BiNe | hir::BiLt | hir::BiGe | hir::BiLe | hir::BiGt => {
base::compare_scalar_types(bcx, lhs, rhs, lhs_t, op.node, binop_debug_loc)
}
_ => {
span_bug!(binop_expr.span, "unexpected binop");
}
};
immediate_rvalue_bcx(bcx, val, binop_ty).to_expr_datumblock()
}
// refinement types would obviate the need for this
#[derive(Clone, Copy)]
enum lazy_binop_ty {
lazy_and,
lazy_or,
}
fn trans_lazy_binop<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
binop_expr: &hir::Expr,
op: lazy_binop_ty,
a: &hir::Expr,
b: &hir::Expr)
-> DatumBlock<'blk, 'tcx, Expr> {
let _icx = push_ctxt("trans_lazy_binop");
let binop_ty = expr_ty(bcx, binop_expr);
let fcx = bcx.fcx;
let DatumBlock {bcx: past_lhs, datum: lhs} = trans(bcx, a);
let lhs = lhs.to_llscalarish(past_lhs);
if past_lhs.unreachable.get() {
return immediate_rvalue_bcx(past_lhs, lhs, binop_ty).to_expr_datumblock();
}
// If the rhs can never be reached, don't generate code for it.
if let Some(cond_val) = const_to_opt_uint(lhs) {
match (cond_val, op) {
(0, lazy_and) |
(1, lazy_or) => {
return immediate_rvalue_bcx(past_lhs, lhs, binop_ty).to_expr_datumblock();
}
_ => { /* continue */ }
}
}
let join = fcx.new_id_block("join", binop_expr.id);
let before_rhs = fcx.new_id_block("before_rhs", b.id);
match op {
lazy_and => CondBr(past_lhs, lhs, before_rhs.llbb, join.llbb, DebugLoc::None),
lazy_or => CondBr(past_lhs, lhs, join.llbb, before_rhs.llbb, DebugLoc::None)
}
let DatumBlock {bcx: past_rhs, datum: rhs} = trans(before_rhs, b);
let rhs = rhs.to_llscalarish(past_rhs);
if past_rhs.unreachable.get() {
return immediate_rvalue_bcx(join, lhs, binop_ty).to_expr_datumblock();
}
Br(past_rhs, join.llbb, DebugLoc::None);
let phi = Phi(join, Type::i1(bcx.ccx()), &[lhs, rhs],
&[past_lhs.llbb, past_rhs.llbb]);
return immediate_rvalue_bcx(join, phi, binop_ty).to_expr_datumblock();
}
fn trans_binary<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
expr: &hir::Expr,
op: hir::BinOp,
lhs: &hir::Expr,
rhs: &hir::Expr)
-> DatumBlock<'blk, 'tcx, Expr> {
let _icx = push_ctxt("trans_binary");
let ccx = bcx.ccx();
// if overloaded, would be RvalueDpsExpr
assert!(!ccx.tcx().is_method_call(expr.id));
match op.node {
hir::BiAnd => {
trans_lazy_binop(bcx, expr, lazy_and, lhs, rhs)
}
hir::BiOr => {
trans_lazy_binop(bcx, expr, lazy_or, lhs, rhs)
}
_ => {
let mut bcx = bcx;
let binop_ty = expr_ty(bcx, expr);
let lhs = unpack_datum!(bcx, trans(bcx, lhs));
let lhs = unpack_datum!(bcx, lhs.to_rvalue_datum(bcx, "binop_lhs"));
debug!("trans_binary (expr {}): lhs={:?}", expr.id, lhs);
let rhs = unpack_datum!(bcx, trans(bcx, rhs));
let rhs = unpack_datum!(bcx, rhs.to_rvalue_datum(bcx, "binop_rhs"));
debug!("trans_binary (expr {}): rhs={:?}", expr.id, rhs);
if type_is_fat_ptr(ccx.tcx(), lhs.ty) {
assert!(type_is_fat_ptr(ccx.tcx(), rhs.ty),
"built-in binary operators on fat pointers are homogeneous");
assert_eq!(binop_ty, bcx.tcx().types.bool);
let val = base::compare_scalar_types(
bcx,
lhs.val,
rhs.val,
lhs.ty,
op.node,
expr.debug_loc());
immediate_rvalue_bcx(bcx, val, binop_ty).to_expr_datumblock()
} else {
assert!(!type_is_fat_ptr(ccx.tcx(), rhs.ty),
"built-in binary operators on fat pointers are homogeneous");
trans_scalar_binop(bcx, expr, binop_ty, op, lhs, rhs)
}
}
}
}
pub fn cast_is_noop<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
expr: &hir::Expr,
t_in: Ty<'tcx>,
t_out: Ty<'tcx>)
-> bool {
if let Some(&CastKind::CoercionCast) = tcx.cast_kinds.borrow().get(&expr.id) {
return true;
}
match (t_in.builtin_deref(true, ty::NoPreference),
t_out.builtin_deref(true, ty::NoPreference)) {
(Some(ty::TypeAndMut{ ty: t_in, .. }), Some(ty::TypeAndMut{ ty: t_out, .. })) => {
t_in == t_out
}
_ => {
// This condition isn't redundant with the check for CoercionCast:
// different types can be substituted into the same type, and
// == equality can be overconservative if there are regions.
t_in == t_out
}
}
}
fn trans_imm_cast<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
expr: &hir::Expr,
id: ast::NodeId)
-> DatumBlock<'blk, 'tcx, Expr>
{
use rustc::ty::cast::CastTy::*;
use rustc::ty::cast::IntTy::*;
fn int_cast(bcx: Block,
lldsttype: Type,
llsrctype: Type,
llsrc: ValueRef,
signed: bool)
-> ValueRef
{
let _icx = push_ctxt("int_cast");
let srcsz = llsrctype.int_width();
let dstsz = lldsttype.int_width();
return if dstsz == srcsz {
BitCast(bcx, llsrc, lldsttype)
} else if srcsz > dstsz {
TruncOrBitCast(bcx, llsrc, lldsttype)
} else if signed {
SExtOrBitCast(bcx, llsrc, lldsttype)
} else {
ZExtOrBitCast(bcx, llsrc, lldsttype)
}
}
fn float_cast(bcx: Block,
lldsttype: Type,
llsrctype: Type,
llsrc: ValueRef)
-> ValueRef
{
let _icx = push_ctxt("float_cast");
let srcsz = llsrctype.float_width();
let dstsz = lldsttype.float_width();
return if dstsz > srcsz {
FPExt(bcx, llsrc, lldsttype)
} else if srcsz > dstsz {
FPTrunc(bcx, llsrc, lldsttype)
} else { llsrc };
}
let _icx = push_ctxt("trans_cast");
let mut bcx = bcx;
let ccx = bcx.ccx();
let t_in = expr_ty_adjusted(bcx, expr);
let t_out = node_id_type(bcx, id);
debug!("trans_cast({:?} as {:?})", t_in, t_out);
let mut ll_t_in = type_of::immediate_type_of(ccx, t_in);
let ll_t_out = type_of::immediate_type_of(ccx, t_out);
// Convert the value to be cast into a ValueRef, either by-ref or
// by-value as appropriate given its type:
let mut datum = unpack_datum!(bcx, trans(bcx, expr));
let datum_ty = monomorphize_type(bcx, datum.ty);
if cast_is_noop(bcx.tcx(), expr, datum_ty, t_out) {
datum.ty = t_out;
return DatumBlock::new(bcx, datum);
}
if type_is_fat_ptr(bcx.tcx(), t_in) {
assert!(datum.kind.is_by_ref());
if type_is_fat_ptr(bcx.tcx(), t_out) {
return DatumBlock::new(bcx, Datum::new(
PointerCast(bcx, datum.val, ll_t_out.ptr_to()),
t_out,
Rvalue::new(ByRef)
)).to_expr_datumblock();
} else {
// Return the address
return immediate_rvalue_bcx(bcx,
PointerCast(bcx,
Load(bcx, get_dataptr(bcx, datum.val)),
ll_t_out),
t_out).to_expr_datumblock();
}
}
let r_t_in = CastTy::from_ty(t_in).expect("bad input type for cast");
let r_t_out = CastTy::from_ty(t_out).expect("bad output type for cast");
let (llexpr, signed) = if let Int(CEnum) = r_t_in {
let repr = adt::represent_type(ccx, t_in);
let datum = unpack_datum!(
bcx, datum.to_lvalue_datum(bcx, "trans_imm_cast", expr.id));
let llexpr_ptr = datum.to_llref();
let discr = adt::trans_get_discr(bcx, &repr, llexpr_ptr,
Some(Type::i64(ccx)), true);
ll_t_in = val_ty(discr);
(discr, adt::is_discr_signed(&repr))
} else {
(datum.to_llscalarish(bcx), t_in.is_signed())
};
let newval = match (r_t_in, r_t_out) {
(Ptr(_), Ptr(_)) | (FnPtr, Ptr(_)) | (RPtr(_), Ptr(_)) => {
PointerCast(bcx, llexpr, ll_t_out)
}
(Ptr(_), Int(_)) | (FnPtr, Int(_)) => PtrToInt(bcx, llexpr, ll_t_out),
(Int(_), Ptr(_)) => IntToPtr(bcx, llexpr, ll_t_out),
(Int(_), Int(_)) => int_cast(bcx, ll_t_out, ll_t_in, llexpr, signed),
(Float, Float) => float_cast(bcx, ll_t_out, ll_t_in, llexpr),
(Int(_), Float) if signed => SIToFP(bcx, llexpr, ll_t_out),
(Int(_), Float) => UIToFP(bcx, llexpr, ll_t_out),
(Float, Int(I)) => FPToSI(bcx, llexpr, ll_t_out),
(Float, Int(_)) => FPToUI(bcx, llexpr, ll_t_out),
_ => span_bug!(expr.span,
"translating unsupported cast: \
{:?} -> {:?}",
t_in,
t_out)
};
return immediate_rvalue_bcx(bcx, newval, t_out).to_expr_datumblock();
}
fn trans_assign_op<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
expr: &hir::Expr,
op: hir::BinOp,
dst: &hir::Expr,
src: &hir::Expr)
-> Block<'blk, 'tcx> {
let _icx = push_ctxt("trans_assign_op");
let mut bcx = bcx;
debug!("trans_assign_op(expr={:?})", expr);
// User-defined operator methods cannot be used with `+=` etc right now
assert!(!bcx.tcx().is_method_call(expr.id));
// Evaluate LHS (destination), which should be an lvalue
let dst = unpack_datum!(bcx, trans_to_lvalue(bcx, dst, "assign_op"));
assert!(!bcx.fcx.type_needs_drop(dst.ty));
let lhs = load_ty(bcx, dst.val, dst.ty);
let lhs = immediate_rvalue(lhs, dst.ty);
// Evaluate RHS - FIXME(#28160) this sucks
let rhs = unpack_datum!(bcx, trans(bcx, &src));
let rhs = unpack_datum!(bcx, rhs.to_rvalue_datum(bcx, "assign_op_rhs"));
// Perform computation and store the result
let result_datum = unpack_datum!(
bcx, trans_scalar_binop(bcx, expr, dst.ty, op, lhs, rhs));
return result_datum.store_to(bcx, dst.val);
}
fn auto_ref<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
datum: Datum<'tcx, Expr>,
expr: &hir::Expr)
-> DatumBlock<'blk, 'tcx, Expr> {
let mut bcx = bcx;
// Ensure cleanup of `datum` if not already scheduled and obtain
// a "by ref" pointer.
let lv_datum = unpack_datum!(bcx, datum.to_lvalue_datum(bcx, "autoref", expr.id));
// Compute final type. Note that we are loose with the region and
// mutability, since those things don't matter in trans.
let referent_ty = lv_datum.ty;
let ptr_ty = bcx.tcx().mk_imm_ref(bcx.tcx().mk_region(ty::ReErased), referent_ty);
// Construct the resulting datum. The right datum to return here would be an Lvalue datum,
// because there is cleanup scheduled and the datum doesn't own the data, but for thin pointers
// we microoptimize it to be an Rvalue datum to avoid the extra alloca and level of
// indirection and for thin pointers, this has no ill effects.
let kind = if type_is_sized(bcx.tcx(), referent_ty) {
RvalueExpr(Rvalue::new(ByValue))
} else {
LvalueExpr(lv_datum.kind)
};
// Get the pointer.
let llref = lv_datum.to_llref();
DatumBlock::new(bcx, Datum::new(llref, ptr_ty, kind))
}
fn deref_multiple<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
expr: &hir::Expr,
datum: Datum<'tcx, Expr>,
times: usize)
-> DatumBlock<'blk, 'tcx, Expr> {
let mut bcx = bcx;
let mut datum = datum;
for i in 0..times {
let method_call = MethodCall::autoderef(expr.id, i as u32);
datum = unpack_datum!(bcx, deref_once(bcx, expr, datum, method_call));
}
DatumBlock { bcx: bcx, datum: datum }
}
fn deref_once<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
expr: &hir::Expr,
datum: Datum<'tcx, Expr>,
method_call: MethodCall)
-> DatumBlock<'blk, 'tcx, Expr> {
let ccx = bcx.ccx();
debug!("deref_once(expr={:?}, datum={:?}, method_call={:?})",
expr, datum, method_call);
let mut bcx = bcx;
// Check for overloaded deref.
let method = ccx.tcx().tables.borrow().method_map.get(&method_call).cloned();
let datum = match method {
Some(method) => {
let method_ty = monomorphize_type(bcx, method.ty);
// Overloaded. Invoke the deref() method, which basically
// converts from the `Smaht<T>` pointer that we have into
// a `&T` pointer. We can then proceed down the normal
// path (below) to dereference that `&T`.
let datum = if method_call.autoderef == 0 {
datum
} else {
// Always perform an AutoPtr when applying an overloaded auto-deref
unpack_datum!(bcx, auto_ref(bcx, datum, expr))
};
let ref_ty = // invoked methods have their LB regions instantiated
ccx.tcx().no_late_bound_regions(&method_ty.fn_ret()).unwrap().unwrap();
let scratch = rvalue_scratch_datum(bcx, ref_ty, "overloaded_deref");
bcx = Callee::method(bcx, method)
.call(bcx, expr.debug_loc(),
ArgOverloadedOp(datum, None),
Some(SaveIn(scratch.val))).bcx;
scratch.to_expr_datum()
}
None => {
// Not overloaded. We already have a pointer we know how to deref.
datum
}
};
let r = match datum.ty.sty {
ty::TyBox(content_ty) => {
// Make sure we have an lvalue datum here to get the
// proper cleanups scheduled
let datum = unpack_datum!(
bcx, datum.to_lvalue_datum(bcx, "deref", expr.id));
if type_is_sized(bcx.tcx(), content_ty) {
let ptr = load_ty(bcx, datum.val, datum.ty);
DatumBlock::new(bcx, Datum::new(ptr, content_ty, LvalueExpr(datum.kind)))
} else {
// A fat pointer and a DST lvalue have the same representation
// just different types. Since there is no temporary for `*e`
// here (because it is unsized), we cannot emulate the sized
// object code path for running drop glue and free. Instead,
// we schedule cleanup for `e`, turning it into an lvalue.
let lval = Lvalue::new("expr::deref_once ty_uniq");
let datum = Datum::new(datum.val, content_ty, LvalueExpr(lval));
DatumBlock::new(bcx, datum)
}
}
ty::TyRawPtr(ty::TypeAndMut { ty: content_ty, .. }) |
ty::TyRef(_, ty::TypeAndMut { ty: content_ty, .. }) => {
let lval = Lvalue::new("expr::deref_once ptr");
if type_is_sized(bcx.tcx(), content_ty) {
let ptr = datum.to_llscalarish(bcx);
// Always generate an lvalue datum, even if datum.mode is
// an rvalue. This is because datum.mode is only an
// rvalue for non-owning pointers like &T or *T, in which
// case cleanup *is* scheduled elsewhere, by the true
// owner (or, in the case of *T, by the user).
DatumBlock::new(bcx, Datum::new(ptr, content_ty, LvalueExpr(lval)))
} else {
// A fat pointer and a DST lvalue have the same representation
// just different types.
DatumBlock::new(bcx, Datum::new(datum.val, content_ty, LvalueExpr(lval)))
}
}
_ => {
span_bug!(
expr.span,
"deref invoked on expr of invalid type {:?}",
datum.ty);
}
};
debug!("deref_once(expr={}, method_call={:?}, result={:?})",
expr.id, method_call, r.datum);
return r;
}
#[derive(Debug)]
enum OverflowOp {
Add,
Sub,
Mul,
Shl,
Shr,
}
impl OverflowOp {
fn codegen_strategy(&self) -> OverflowCodegen {
use self::OverflowCodegen::{ViaIntrinsic, ViaInputCheck};
match *self {
OverflowOp::Add => ViaIntrinsic(OverflowOpViaIntrinsic::Add),
OverflowOp::Sub => ViaIntrinsic(OverflowOpViaIntrinsic::Sub),
OverflowOp::Mul => ViaIntrinsic(OverflowOpViaIntrinsic::Mul),
OverflowOp::Shl => ViaInputCheck(OverflowOpViaInputCheck::Shl),
OverflowOp::Shr => ViaInputCheck(OverflowOpViaInputCheck::Shr),
}
}
}
enum OverflowCodegen {
ViaIntrinsic(OverflowOpViaIntrinsic),
ViaInputCheck(OverflowOpViaInputCheck),
}
enum OverflowOpViaInputCheck { Shl, Shr, }
#[derive(Debug)]
enum OverflowOpViaIntrinsic { Add, Sub, Mul, }
impl OverflowOpViaIntrinsic {
fn to_intrinsic<'blk, 'tcx>(&self, bcx: Block<'blk, 'tcx>, lhs_ty: Ty) -> ValueRef {
let name = self.to_intrinsic_name(bcx.tcx(), lhs_ty);
bcx.ccx().get_intrinsic(&name)
}
fn to_intrinsic_name(&self, tcx: TyCtxt, ty: Ty) -> &'static str {
use syntax::ast::IntTy::*;
use syntax::ast::UintTy::*;
use rustc::ty::{TyInt, TyUint};
let new_sty = match ty.sty {
TyInt(Is) => match &tcx.sess.target.target.target_pointer_width[..] {
"16" => TyInt(I16),
"32" => TyInt(I32),
"64" => TyInt(I64),
_ => bug!("unsupported target word size")
},
TyUint(Us) => match &tcx.sess.target.target.target_pointer_width[..] {
"16" => TyUint(U16),
"32" => TyUint(U32),
"64" => TyUint(U64),
_ => bug!("unsupported target word size")
},
ref t @ TyUint(_) | ref t @ TyInt(_) => t.clone(),
_ => bug!("tried to get overflow intrinsic for {:?} applied to non-int type",
*self)
};
match *self {
OverflowOpViaIntrinsic::Add => match new_sty {
TyInt(I8) => "llvm.sadd.with.overflow.i8",
TyInt(I16) => "llvm.sadd.with.overflow.i16",
TyInt(I32) => "llvm.sadd.with.overflow.i32",
TyInt(I64) => "llvm.sadd.with.overflow.i64",
TyUint(U8) => "llvm.uadd.with.overflow.i8",
TyUint(U16) => "llvm.uadd.with.overflow.i16",
TyUint(U32) => "llvm.uadd.with.overflow.i32",
TyUint(U64) => "llvm.uadd.with.overflow.i64",
_ => bug!(),
},
OverflowOpViaIntrinsic::Sub => match new_sty {
TyInt(I8) => "llvm.ssub.with.overflow.i8",
TyInt(I16) => "llvm.ssub.with.overflow.i16",
TyInt(I32) => "llvm.ssub.with.overflow.i32",
TyInt(I64) => "llvm.ssub.with.overflow.i64",
TyUint(U8) => "llvm.usub.with.overflow.i8",
TyUint(U16) => "llvm.usub.with.overflow.i16",
TyUint(U32) => "llvm.usub.with.overflow.i32",
TyUint(U64) => "llvm.usub.with.overflow.i64",
_ => bug!(),
},
OverflowOpViaIntrinsic::Mul => match new_sty {
TyInt(I8) => "llvm.smul.with.overflow.i8",
TyInt(I16) => "llvm.smul.with.overflow.i16",
TyInt(I32) => "llvm.smul.with.overflow.i32",
TyInt(I64) => "llvm.smul.with.overflow.i64",
TyUint(U8) => "llvm.umul.with.overflow.i8",
TyUint(U16) => "llvm.umul.with.overflow.i16",
TyUint(U32) => "llvm.umul.with.overflow.i32",
TyUint(U64) => "llvm.umul.with.overflow.i64",
_ => bug!(),
},
}
}
fn build_intrinsic_call<'blk, 'tcx>(&self, bcx: Block<'blk, 'tcx>,
info: NodeIdAndSpan,
lhs_t: Ty<'tcx>, lhs: ValueRef,
rhs: ValueRef,
binop_debug_loc: DebugLoc)
-> (Block<'blk, 'tcx>, ValueRef) {
use rustc_const_math::{ConstMathErr, Op};
let llfn = self.to_intrinsic(bcx, lhs_t);
let val = Call(bcx, llfn, &[lhs, rhs], binop_debug_loc);
let result = ExtractValue(bcx, val, 0); // iN operation result
let overflow = ExtractValue(bcx, val, 1); // i1 "did it overflow?"
let cond = ICmp(bcx, llvm::IntEQ, overflow, C_integral(Type::i1(bcx.ccx()), 1, false),
binop_debug_loc);
let expect = bcx.ccx().get_intrinsic(&"llvm.expect.i1");
let expected = Call(bcx, expect, &[cond, C_bool(bcx.ccx(), false)],
binop_debug_loc);
let op = match *self {
OverflowOpViaIntrinsic::Add => Op::Add,
OverflowOpViaIntrinsic::Sub => Op::Sub,
OverflowOpViaIntrinsic::Mul => Op::Mul
};
let bcx =
base::with_cond(bcx, expected, |bcx|
controlflow::trans_fail(bcx, info,
InternedString::new(ConstMathErr::Overflow(op).description())));
(bcx, result)
}
}
impl OverflowOpViaInputCheck {
fn build_with_input_check<'blk, 'tcx>(&self,
bcx: Block<'blk, 'tcx>,
info: NodeIdAndSpan,
lhs_t: Ty<'tcx>,
lhs: ValueRef,
rhs: ValueRef,
binop_debug_loc: DebugLoc)
-> (Block<'blk, 'tcx>, ValueRef)
{
use rustc_const_math::{ConstMathErr, Op};
let lhs_llty = val_ty(lhs);
let rhs_llty = val_ty(rhs);
// Panic if any bits are set outside of bits that we always
// mask in.
//
// Note that the mask's value is derived from the LHS type
// (since that is where the 32/64 distinction is relevant) but
// the mask's type must match the RHS type (since they will
// both be fed into an and-binop)
let invert_mask = shift_mask_val(bcx, lhs_llty, rhs_llty, true);
let outer_bits = And(bcx, rhs, invert_mask, binop_debug_loc);
let cond = build_nonzero_check(bcx, outer_bits, binop_debug_loc);
let (result, op) = match *self {
OverflowOpViaInputCheck::Shl =>
(build_unchecked_lshift(bcx, lhs, rhs, binop_debug_loc), Op::Shl),
OverflowOpViaInputCheck::Shr =>
(build_unchecked_rshift(bcx, lhs_t, lhs, rhs, binop_debug_loc), Op::Shr)
};
let bcx =
base::with_cond(bcx, cond, |bcx|
controlflow::trans_fail(bcx, info,
InternedString::new(ConstMathErr::Overflow(op).description())));
(bcx, result)
}
}
// Check if an integer or vector contains a nonzero element.
fn build_nonzero_check<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
value: ValueRef,
binop_debug_loc: DebugLoc) -> ValueRef {
let llty = val_ty(value);
let kind = llty.kind();
match kind {
TypeKind::Integer => ICmp(bcx, llvm::IntNE, value, C_null(llty), binop_debug_loc),
TypeKind::Vector => {
// Check if any elements of the vector are nonzero by treating
// it as a wide integer and checking if the integer is nonzero.
let width = llty.vector_length() as u64 * llty.element_type().int_width();
let int_value = BitCast(bcx, value, Type::ix(bcx.ccx(), width));
build_nonzero_check(bcx, int_value, binop_debug_loc)
},
_ => bug!("build_nonzero_check: expected Integer or Vector, found {:?}", kind),
}
}
fn with_overflow_check<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, oop: OverflowOp, info: NodeIdAndSpan,
lhs_t: Ty<'tcx>, lhs: ValueRef,
rhs: ValueRef,
binop_debug_loc: DebugLoc)
-> (Block<'blk, 'tcx>, ValueRef) {
if bcx.unreachable.get() { return (bcx, _Undef(lhs)); }
if bcx.ccx().check_overflow() {
match oop.codegen_strategy() {
OverflowCodegen::ViaIntrinsic(oop) =>
oop.build_intrinsic_call(bcx, info, lhs_t, lhs, rhs, binop_debug_loc),
OverflowCodegen::ViaInputCheck(oop) =>
oop.build_with_input_check(bcx, info, lhs_t, lhs, rhs, binop_debug_loc),
}
} else {
let res = match oop {
OverflowOp::Add => Add(bcx, lhs, rhs, binop_debug_loc),
OverflowOp::Sub => Sub(bcx, lhs, rhs, binop_debug_loc),
OverflowOp::Mul => Mul(bcx, lhs, rhs, binop_debug_loc),
OverflowOp::Shl =>
build_unchecked_lshift(bcx, lhs, rhs, binop_debug_loc),
OverflowOp::Shr =>
build_unchecked_rshift(bcx, lhs_t, lhs, rhs, binop_debug_loc),
};
(bcx, res)
}
}
/// We categorize expressions into three kinds. The distinction between
/// lvalue/rvalue is fundamental to the language. The distinction between the
/// two kinds of rvalues is an artifact of trans which reflects how we will
/// generate code for that kind of expression. See trans/expr.rs for more
/// information.
#[derive(Copy, Clone)]
enum ExprKind {
Lvalue,
RvalueDps,
RvalueDatum,
RvalueStmt
}
fn expr_kind<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, expr: &hir::Expr) -> ExprKind {
if tcx.is_method_call(expr.id) {
// Overloaded operations are generally calls, and hence they are
// generated via DPS, but there are a few exceptions:
return match expr.node {
// `a += b` has a unit result.
hir::ExprAssignOp(..) => ExprKind::RvalueStmt,
// the deref method invoked for `*a` always yields an `&T`
hir::ExprUnary(hir::UnDeref, _) => ExprKind::Lvalue,
// the index method invoked for `a[i]` always yields an `&T`
hir::ExprIndex(..) => ExprKind::Lvalue,
// in the general case, result could be any type, use DPS
_ => ExprKind::RvalueDps
};
}
match expr.node {
hir::ExprPath(..) => {
match tcx.expect_def(expr.id) {
// Put functions and ctors with the ADTs, as they
// are zero-sized, so DPS is the cheapest option.
Def::Struct(..) | Def::Variant(..) |
Def::Fn(..) | Def::Method(..) => {
ExprKind::RvalueDps
}
// Note: there is actually a good case to be made that
// DefArg's, particularly those of immediate type, ought to
// considered rvalues.
Def::Static(..) |
Def::Upvar(..) |
Def::Local(..) => ExprKind::Lvalue,
Def::Const(..) |
Def::AssociatedConst(..) => ExprKind::RvalueDatum,
def => {
span_bug!(
expr.span,
"uncategorized def for expr {}: {:?}",
expr.id,
def);
}
}
}
hir::ExprType(ref expr, _) => {
expr_kind(tcx, expr)
}
hir::ExprUnary(hir::UnDeref, _) |
hir::ExprField(..) |
hir::ExprTupField(..) |
hir::ExprIndex(..) => {
ExprKind::Lvalue
}
hir::ExprCall(..) |
hir::ExprMethodCall(..) |
hir::ExprStruct(..) |
hir::ExprTup(..) |
hir::ExprIf(..) |
hir::ExprMatch(..) |
hir::ExprClosure(..) |
hir::ExprBlock(..) |
hir::ExprRepeat(..) |
hir::ExprVec(..) => {
ExprKind::RvalueDps
}
hir::ExprLit(ref lit) if lit.node.is_str() => {
ExprKind::RvalueDps
}
hir::ExprBreak(..) |
hir::ExprAgain(..) |
hir::ExprRet(..) |
hir::ExprWhile(..) |
hir::ExprLoop(..) |
hir::ExprAssign(..) |
hir::ExprInlineAsm(..) |
hir::ExprAssignOp(..) => {
ExprKind::RvalueStmt
}
hir::ExprLit(_) | // Note: LitStr is carved out above
hir::ExprUnary(..) |
hir::ExprBox(_) |
hir::ExprAddrOf(..) |
hir::ExprBinary(..) |
hir::ExprCast(..) => {
ExprKind::RvalueDatum
}
}
}