f1ce693e61
The support for sized deallocation is nearly complete. The only known missing pieces are `Box<str>`, `Box<[T]>` and `proc`.
1822 lines
66 KiB
Rust
1822 lines
66 KiB
Rust
// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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/*!
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* # Translation of Expressions
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*
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* Public entry points:
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*
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* - `trans_into(bcx, expr, dest) -> bcx`: evaluates an expression,
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* storing the result into `dest`. This is the preferred form, if you
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* can manage it.
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*
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* - `trans(bcx, expr) -> DatumBlock`: evaluates an expression, yielding
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* `Datum` with the result. You can then store the datum, inspect
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* the value, etc. This may introduce temporaries if the datum is a
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* structural type.
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*
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* - `trans_to_lvalue(bcx, expr, "...") -> DatumBlock`: evaluates an
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* expression and ensures that the result has a cleanup associated with it,
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* creating a temporary stack slot if necessary.
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*
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* - `trans_local_var -> Datum`: looks up a local variable or upvar.
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*
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* See doc.rs for more comments.
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*/
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#![allow(non_camel_case_types)]
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use back::abi;
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use lib::llvm::{ValueRef, llvm};
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use lib;
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use metadata::csearch;
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use middle::lang_items::MallocFnLangItem;
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use middle::trans::_match;
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use middle::trans::adt;
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use middle::trans::asm;
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use middle::trans::base::*;
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use middle::trans::base;
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use middle::trans::build::*;
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use middle::trans::callee;
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use middle::trans::cleanup;
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use middle::trans::cleanup::CleanupMethods;
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use middle::trans::closure;
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use middle::trans::common::*;
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use middle::trans::consts;
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use middle::trans::controlflow;
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use middle::trans::datum::*;
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use middle::trans::debuginfo;
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use middle::trans::glue;
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use middle::trans::machine;
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use middle::trans::meth;
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use middle::trans::inline;
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use middle::trans::tvec;
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use middle::trans::type_of;
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use middle::ty::struct_fields;
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use middle::ty::{AutoBorrowObj, AutoDerefRef, AutoAddEnv, AutoObject, AutoUnsafe};
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use middle::ty::{AutoPtr, AutoBorrowVec, AutoBorrowVecRef};
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use middle::ty;
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use middle::typeck::MethodCall;
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use util::common::indenter;
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use util::ppaux::Repr;
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use util::nodemap::NodeMap;
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use middle::trans::machine::{llalign_of_min, llsize_of, llsize_of_alloc};
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use middle::trans::type_::Type;
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use syntax::ast;
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use syntax::codemap;
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use syntax::print::pprust::{expr_to_str};
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// Destinations
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// These are passed around by the code generating functions to track the
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// destination of a computation's value.
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#[deriving(Eq)]
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pub enum Dest {
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SaveIn(ValueRef),
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Ignore,
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}
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impl Dest {
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pub fn to_str(&self, ccx: &CrateContext) -> StrBuf {
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match *self {
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SaveIn(v) => format_strbuf!("SaveIn({})", ccx.tn.val_to_str(v)),
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Ignore => "Ignore".to_strbuf()
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}
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}
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}
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pub fn trans_into<'a>(bcx: &'a Block<'a>,
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expr: &ast::Expr,
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dest: Dest)
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-> &'a Block<'a> {
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/*!
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* This function is equivalent to `trans(bcx, expr).store_to_dest(dest)`
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* but it may generate better optimized LLVM code.
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*/
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let mut bcx = bcx;
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if bcx.tcx().adjustments.borrow().contains_key(&expr.id) {
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// use trans, which may be less efficient but
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// which will perform the adjustments:
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let datum = unpack_datum!(bcx, trans(bcx, expr));
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return datum.store_to_dest(bcx, dest, expr.id)
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}
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debug!("trans_into() expr={}", expr.repr(bcx.tcx()));
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debuginfo::set_source_location(bcx.fcx, expr.id, expr.span);
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bcx.fcx.push_ast_cleanup_scope(expr.id);
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let kind = ty::expr_kind(bcx.tcx(), expr);
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bcx = match kind {
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ty::LvalueExpr | ty::RvalueDatumExpr => {
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trans_unadjusted(bcx, expr).store_to_dest(dest, expr.id)
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}
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ty::RvalueDpsExpr => {
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trans_rvalue_dps_unadjusted(bcx, expr, dest)
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}
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ty::RvalueStmtExpr => {
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trans_rvalue_stmt_unadjusted(bcx, expr)
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}
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};
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bcx.fcx.pop_and_trans_ast_cleanup_scope(bcx, expr.id)
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}
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pub fn trans<'a>(bcx: &'a Block<'a>,
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expr: &ast::Expr)
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-> DatumBlock<'a, Expr> {
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/*!
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* Translates an expression, returning a datum (and new block)
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* encapsulating the result. When possible, it is preferred to
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* use `trans_into`, as that may avoid creating a temporary on
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* the stack.
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*/
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debug!("trans(expr={})", bcx.expr_to_str(expr));
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let mut bcx = bcx;
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let fcx = bcx.fcx;
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fcx.push_ast_cleanup_scope(expr.id);
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let datum = unpack_datum!(bcx, trans_unadjusted(bcx, expr));
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let datum = unpack_datum!(bcx, apply_adjustments(bcx, expr, datum));
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bcx = fcx.pop_and_trans_ast_cleanup_scope(bcx, expr.id);
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return DatumBlock(bcx, datum);
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}
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fn apply_adjustments<'a>(bcx: &'a Block<'a>,
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expr: &ast::Expr,
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datum: Datum<Expr>)
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-> DatumBlock<'a, Expr> {
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/*!
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* Helper for trans that apply adjustments from `expr` to `datum`,
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* which should be the unadjusted translation of `expr`.
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*/
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let mut bcx = bcx;
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let mut datum = datum;
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let adjustment = match bcx.tcx().adjustments.borrow().find_copy(&expr.id) {
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None => {
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return DatumBlock(bcx, datum);
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}
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Some(adj) => { adj }
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};
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debug!("unadjusted datum for expr {}: {}",
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expr.id, datum.to_str(bcx.ccx()));
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match adjustment {
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AutoAddEnv(..) => {
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datum = unpack_datum!(bcx, add_env(bcx, expr, datum));
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}
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AutoDerefRef(ref adj) => {
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if adj.autoderefs > 0 {
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datum = unpack_datum!(
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bcx, deref_multiple(bcx, expr, datum, adj.autoderefs));
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}
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datum = match adj.autoref {
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None => {
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datum
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}
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Some(AutoUnsafe(..)) | // region + unsafe ptrs have same repr
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Some(AutoPtr(..)) => {
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unpack_datum!(bcx, auto_ref(bcx, datum, expr))
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}
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Some(AutoBorrowVec(..)) => {
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unpack_datum!(bcx, auto_slice(bcx, expr, datum))
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}
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Some(AutoBorrowVecRef(..)) => {
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unpack_datum!(bcx, auto_slice_and_ref(bcx, expr, datum))
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}
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Some(AutoBorrowObj(..)) => {
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unpack_datum!(bcx, auto_borrow_obj(bcx, expr, datum))
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}
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};
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}
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AutoObject(..) => {
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let adjusted_ty = ty::expr_ty_adjusted(bcx.tcx(), expr);
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let scratch = rvalue_scratch_datum(bcx, adjusted_ty, "__adjust");
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bcx = meth::trans_trait_cast(
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bcx, datum, expr.id, SaveIn(scratch.val));
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datum = scratch.to_expr_datum();
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}
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}
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debug!("after adjustments, datum={}", datum.to_str(bcx.ccx()));
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return DatumBlock {bcx: bcx, datum: datum};
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fn auto_slice<'a>(
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bcx: &'a Block<'a>,
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expr: &ast::Expr,
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datum: Datum<Expr>)
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-> DatumBlock<'a, Expr> {
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// This is not the most efficient thing possible; since slices
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// are two words it'd be better if this were compiled in
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// 'dest' mode, but I can't find a nice way to structure the
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// code and keep it DRY that accommodates that use case at the
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// moment.
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let mut bcx = bcx;
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let tcx = bcx.tcx();
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let unit_ty = ty::sequence_element_type(tcx, datum.ty);
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// Arrange cleanup, if not already done. This is needed in
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// case we are auto-slicing an owned vector or some such.
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let datum = unpack_datum!(
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bcx, datum.to_lvalue_datum(bcx, "auto_slice", expr.id));
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let (base, len) = datum.get_vec_base_and_len(bcx);
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// this type may have a different region/mutability than the
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// real one, but it will have the same runtime representation
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let slice_ty = ty::mk_slice(tcx, ty::ReStatic,
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ty::mt { ty: unit_ty, mutbl: ast::MutImmutable });
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let scratch = rvalue_scratch_datum(bcx, slice_ty, "__adjust");
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Store(bcx, base, GEPi(bcx, scratch.val, [0u, abi::slice_elt_base]));
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Store(bcx, len, GEPi(bcx, scratch.val, [0u, abi::slice_elt_len]));
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DatumBlock(bcx, scratch.to_expr_datum())
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}
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fn add_env<'a>(bcx: &'a Block<'a>,
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expr: &ast::Expr,
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datum: Datum<Expr>)
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-> DatumBlock<'a, Expr> {
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// This is not the most efficient thing possible; since closures
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// are two words it'd be better if this were compiled in
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// 'dest' mode, but I can't find a nice way to structure the
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// code and keep it DRY that accommodates that use case at the
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// moment.
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let closure_ty = expr_ty_adjusted(bcx, expr);
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let fn_ptr = datum.to_llscalarish(bcx);
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let def = ty::resolve_expr(bcx.tcx(), expr);
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closure::make_closure_from_bare_fn(bcx, closure_ty, def, fn_ptr)
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}
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fn auto_slice_and_ref<'a>(
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bcx: &'a Block<'a>,
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expr: &ast::Expr,
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datum: Datum<Expr>)
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-> DatumBlock<'a, Expr> {
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let DatumBlock { bcx, datum } = auto_slice(bcx, expr, datum);
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auto_ref(bcx, datum, expr)
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}
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fn auto_borrow_obj<'a>(bcx: &'a Block<'a>,
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expr: &ast::Expr,
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source_datum: Datum<Expr>)
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-> DatumBlock<'a, Expr> {
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let tcx = bcx.tcx();
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let target_obj_ty = expr_ty_adjusted(bcx, expr);
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debug!("auto_borrow_obj(target={})", target_obj_ty.repr(tcx));
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let mut datum = source_datum.to_expr_datum();
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datum.ty = target_obj_ty;
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DatumBlock(bcx, datum)
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}
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}
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pub fn trans_to_lvalue<'a>(bcx: &'a Block<'a>,
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expr: &ast::Expr,
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name: &str)
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-> DatumBlock<'a, Lvalue> {
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/*!
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* Translates an expression in "lvalue" mode -- meaning that it
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* returns a reference to the memory that the expr represents.
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*
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* If this expression is an rvalue, this implies introducing a
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* temporary. In other words, something like `x().f` is
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* translated into roughly the equivalent of
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*
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* { tmp = x(); tmp.f }
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*/
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let mut bcx = bcx;
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let datum = unpack_datum!(bcx, trans(bcx, expr));
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return datum.to_lvalue_datum(bcx, name, expr.id);
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}
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fn trans_unadjusted<'a>(bcx: &'a Block<'a>,
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expr: &ast::Expr)
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-> DatumBlock<'a, Expr> {
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/*!
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* A version of `trans` that ignores adjustments. You almost
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* certainly do not want to call this directly.
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*/
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let mut bcx = bcx;
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debug!("trans_unadjusted(expr={})", bcx.expr_to_str(expr));
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let _indenter = indenter();
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debuginfo::set_source_location(bcx.fcx, expr.id, expr.span);
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return match ty::expr_kind(bcx.tcx(), expr) {
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ty::LvalueExpr | ty::RvalueDatumExpr => {
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let datum = unpack_datum!(bcx, {
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trans_datum_unadjusted(bcx, expr)
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});
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DatumBlock {bcx: bcx, datum: datum}
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}
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ty::RvalueStmtExpr => {
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bcx = trans_rvalue_stmt_unadjusted(bcx, expr);
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nil(bcx, expr_ty(bcx, expr))
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}
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ty::RvalueDpsExpr => {
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let ty = expr_ty(bcx, expr);
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if type_is_zero_size(bcx.ccx(), ty) {
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bcx = trans_rvalue_dps_unadjusted(bcx, expr, Ignore);
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nil(bcx, ty)
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} else {
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let scratch = rvalue_scratch_datum(bcx, ty, "");
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bcx = trans_rvalue_dps_unadjusted(
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bcx, expr, SaveIn(scratch.val));
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// Note: this is not obviously a good idea. It causes
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// immediate values to be loaded immediately after a
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// return from a call or other similar expression,
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// which in turn leads to alloca's having shorter
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// lifetimes and hence larger stack frames. However,
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// in turn it can lead to more register pressure.
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// Still, in practice it seems to increase
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// performance, since we have fewer problems with
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// morestack churn.
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let scratch = unpack_datum!(
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bcx, scratch.to_appropriate_datum(bcx));
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DatumBlock(bcx, scratch.to_expr_datum())
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}
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}
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};
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fn nil<'a>(bcx: &'a Block<'a>, ty: ty::t) -> DatumBlock<'a, Expr> {
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let llval = C_undef(type_of::type_of(bcx.ccx(), ty));
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let datum = immediate_rvalue(llval, ty);
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DatumBlock(bcx, datum.to_expr_datum())
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}
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}
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fn trans_datum_unadjusted<'a>(bcx: &'a Block<'a>,
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expr: &ast::Expr)
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-> DatumBlock<'a, Expr> {
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let mut bcx = bcx;
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let fcx = bcx.fcx;
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let _icx = push_ctxt("trans_datum_unadjusted");
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match expr.node {
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ast::ExprParen(e) => {
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trans(bcx, e)
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}
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ast::ExprPath(_) => {
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trans_def(bcx, expr, bcx.def(expr.id))
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}
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ast::ExprField(base, ident, _) => {
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trans_rec_field(bcx, base, ident)
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}
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ast::ExprIndex(base, idx) => {
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trans_index(bcx, expr, base, idx)
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}
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ast::ExprVstore(contents, ast::ExprVstoreUniq) => {
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fcx.push_ast_cleanup_scope(contents.id);
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let datum = unpack_datum!(
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bcx, tvec::trans_uniq_vstore(bcx, expr, contents));
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bcx = fcx.pop_and_trans_ast_cleanup_scope(bcx, contents.id);
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DatumBlock(bcx, datum)
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}
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ast::ExprBox(_, contents) => {
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// Special case for `box T`. (The other case, for GC, is handled
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// in `trans_rvalue_dps_unadjusted`.)
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let box_ty = expr_ty(bcx, expr);
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let contents_ty = expr_ty(bcx, contents);
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trans_uniq_expr(bcx, box_ty, contents, contents_ty)
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}
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ast::ExprLit(lit) => trans_immediate_lit(bcx, expr, (*lit).clone()),
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ast::ExprBinary(op, lhs, rhs) => {
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trans_binary(bcx, expr, op, lhs, rhs)
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}
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ast::ExprUnary(op, x) => {
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trans_unary(bcx, expr, op, x)
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}
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ast::ExprAddrOf(_, x) => {
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trans_addr_of(bcx, expr, x)
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}
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ast::ExprCast(val, _) => {
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// Datum output mode means this is a scalar cast:
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trans_imm_cast(bcx, val, expr.id)
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}
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_ => {
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bcx.tcx().sess.span_bug(
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expr.span,
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format!("trans_rvalue_datum_unadjusted reached \
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fall-through case: {:?}",
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expr.node));
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}
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}
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}
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fn trans_rec_field<'a>(bcx: &'a Block<'a>,
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base: &ast::Expr,
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field: ast::Ident)
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-> DatumBlock<'a, Expr> {
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//! Translates `base.field`.
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let mut bcx = bcx;
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let _icx = push_ctxt("trans_rec_field");
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let base_datum = unpack_datum!(bcx, trans_to_lvalue(bcx, base, "field"));
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let repr = adt::represent_type(bcx.ccx(), base_datum.ty);
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with_field_tys(bcx.tcx(), base_datum.ty, None, |discr, field_tys| {
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let ix = ty::field_idx_strict(bcx.tcx(), field.name, field_tys);
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let d = base_datum.get_element(
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field_tys[ix].mt.ty,
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|srcval| adt::trans_field_ptr(bcx, &*repr, srcval, discr, ix));
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DatumBlock { datum: d.to_expr_datum(), bcx: bcx }
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})
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}
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fn trans_index<'a>(bcx: &'a Block<'a>,
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index_expr: &ast::Expr,
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base: &ast::Expr,
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idx: &ast::Expr)
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-> DatumBlock<'a, Expr> {
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//! Translates `base[idx]`.
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let _icx = push_ctxt("trans_index");
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let ccx = bcx.ccx();
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let mut bcx = bcx;
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let base_datum = unpack_datum!(bcx, trans_to_lvalue(bcx, base, "index"));
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|
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// Translate index expression and cast to a suitable LLVM integer.
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// 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 ty::type_is_signed(expr_ty(bcx, idx)) {
|
|
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 vt = tvec::vec_types(bcx, ty::sequence_element_type(bcx.tcx(), base_datum.ty));
|
|
base::maybe_name_value(bcx.ccx(), vt.llunit_size, "unit_sz");
|
|
|
|
let (base, len) = base_datum.get_vec_base_and_len(bcx);
|
|
|
|
debug!("trans_index: base {}", bcx.val_to_str(base));
|
|
debug!("trans_index: len {}", bcx.val_to_str(len));
|
|
|
|
let bounds_check = ICmp(bcx, lib::llvm::IntUGE, ix_val, len);
|
|
let expect = ccx.get_intrinsic(&("llvm.expect.i1"));
|
|
let expected = Call(bcx, expect, [bounds_check, C_i1(ccx, false)], []);
|
|
let bcx = with_cond(bcx, expected, |bcx| {
|
|
controlflow::trans_fail_bounds_check(bcx, index_expr.span, ix_val, len)
|
|
});
|
|
let elt = InBoundsGEP(bcx, base, [ix_val]);
|
|
let elt = PointerCast(bcx, elt, vt.llunit_ty.ptr_to());
|
|
DatumBlock(bcx, Datum(elt, vt.unit_ty, LvalueExpr))
|
|
}
|
|
|
|
fn trans_def<'a>(bcx: &'a Block<'a>,
|
|
ref_expr: &ast::Expr,
|
|
def: ast::Def)
|
|
-> DatumBlock<'a, Expr>
|
|
{
|
|
//! Translates a reference to a path.
|
|
|
|
let _icx = push_ctxt("trans_def_lvalue");
|
|
match def {
|
|
ast::DefFn(..) | ast::DefStaticMethod(..) |
|
|
ast::DefStruct(_) | ast::DefVariant(..) => {
|
|
trans_def_fn_unadjusted(bcx, ref_expr, def)
|
|
}
|
|
ast::DefStatic(did, _) => {
|
|
let const_ty = expr_ty(bcx, ref_expr);
|
|
|
|
fn get_did(ccx: &CrateContext, did: ast::DefId)
|
|
-> ast::DefId {
|
|
if did.krate != ast::LOCAL_CRATE {
|
|
inline::maybe_instantiate_inline(ccx, did)
|
|
} else {
|
|
did
|
|
}
|
|
}
|
|
|
|
fn get_val<'a>(bcx: &'a Block<'a>, did: ast::DefId, const_ty: ty::t)
|
|
-> ValueRef {
|
|
// For external constants, we don't inline.
|
|
if did.krate == ast::LOCAL_CRATE {
|
|
// The LLVM global has the type of its initializer,
|
|
// which may not be equal to the enum's type for
|
|
// non-C-like enums.
|
|
let val = base::get_item_val(bcx.ccx(), did.node);
|
|
let pty = type_of::type_of(bcx.ccx(), const_ty).ptr_to();
|
|
PointerCast(bcx, val, pty)
|
|
} else {
|
|
match bcx.ccx().extern_const_values.borrow().find(&did) {
|
|
None => {} // Continue.
|
|
Some(llval) => {
|
|
return *llval;
|
|
}
|
|
}
|
|
|
|
unsafe {
|
|
let llty = type_of::type_of(bcx.ccx(), const_ty);
|
|
let symbol = csearch::get_symbol(
|
|
&bcx.ccx().sess().cstore,
|
|
did);
|
|
let llval = symbol.as_slice().with_c_str(|buf| {
|
|
llvm::LLVMAddGlobal(bcx.ccx().llmod,
|
|
llty.to_ref(),
|
|
buf)
|
|
});
|
|
bcx.ccx().extern_const_values.borrow_mut()
|
|
.insert(did, llval);
|
|
llval
|
|
}
|
|
}
|
|
}
|
|
|
|
let did = get_did(bcx.ccx(), did);
|
|
let val = get_val(bcx, did, const_ty);
|
|
DatumBlock(bcx, Datum(val, const_ty, LvalueExpr))
|
|
}
|
|
_ => {
|
|
DatumBlock(bcx, trans_local_var(bcx, def).to_expr_datum())
|
|
}
|
|
}
|
|
}
|
|
|
|
fn trans_rvalue_stmt_unadjusted<'a>(bcx: &'a Block<'a>,
|
|
expr: &ast::Expr)
|
|
-> &'a Block<'a> {
|
|
let mut bcx = bcx;
|
|
let _icx = push_ctxt("trans_rvalue_stmt");
|
|
|
|
if bcx.unreachable.get() {
|
|
return bcx;
|
|
}
|
|
|
|
match expr.node {
|
|
ast::ExprParen(e) => {
|
|
trans_into(bcx, e, Ignore)
|
|
}
|
|
ast::ExprBreak(label_opt) => {
|
|
controlflow::trans_break(bcx, expr.id, label_opt)
|
|
}
|
|
ast::ExprAgain(label_opt) => {
|
|
controlflow::trans_cont(bcx, expr.id, label_opt)
|
|
}
|
|
ast::ExprRet(ex) => {
|
|
controlflow::trans_ret(bcx, ex)
|
|
}
|
|
ast::ExprWhile(cond, body) => {
|
|
controlflow::trans_while(bcx, expr.id, cond, body)
|
|
}
|
|
ast::ExprLoop(body, _) => {
|
|
controlflow::trans_loop(bcx, expr.id, body)
|
|
}
|
|
ast::ExprAssign(dst, src) => {
|
|
let src_datum = unpack_datum!(bcx, trans(bcx, src));
|
|
let dst_datum = unpack_datum!(bcx, trans_to_lvalue(bcx, dst, "assign"));
|
|
|
|
if ty::type_needs_drop(bcx.tcx(), 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`.
|
|
let src_datum = unpack_datum!(
|
|
bcx, src_datum.to_rvalue_datum(bcx, "ExprAssign"));
|
|
bcx = glue::drop_ty(bcx, dst_datum.val, dst_datum.ty);
|
|
src_datum.store_to(bcx, dst_datum.val)
|
|
} else {
|
|
src_datum.store_to(bcx, dst_datum.val)
|
|
}
|
|
}
|
|
ast::ExprAssignOp(op, dst, src) => {
|
|
trans_assign_op(bcx, expr, op, dst, src)
|
|
}
|
|
ast::ExprInlineAsm(ref a) => {
|
|
asm::trans_inline_asm(bcx, a)
|
|
}
|
|
_ => {
|
|
bcx.tcx().sess.span_bug(
|
|
expr.span,
|
|
format!("trans_rvalue_stmt_unadjusted reached \
|
|
fall-through case: {:?}",
|
|
expr.node));
|
|
}
|
|
}
|
|
}
|
|
|
|
fn trans_rvalue_dps_unadjusted<'a>(bcx: &'a Block<'a>,
|
|
expr: &ast::Expr,
|
|
dest: Dest)
|
|
-> &'a Block<'a> {
|
|
let _icx = push_ctxt("trans_rvalue_dps_unadjusted");
|
|
let mut bcx = bcx;
|
|
let tcx = bcx.tcx();
|
|
let fcx = bcx.fcx;
|
|
|
|
match expr.node {
|
|
ast::ExprParen(e) => {
|
|
trans_into(bcx, e, dest)
|
|
}
|
|
ast::ExprPath(_) => {
|
|
trans_def_dps_unadjusted(bcx, expr, bcx.def(expr.id), dest)
|
|
}
|
|
ast::ExprIf(cond, thn, els) => {
|
|
controlflow::trans_if(bcx, expr.id, cond, thn, els, dest)
|
|
}
|
|
ast::ExprMatch(discr, ref arms) => {
|
|
_match::trans_match(bcx, expr, discr, arms.as_slice(), dest)
|
|
}
|
|
ast::ExprBlock(blk) => {
|
|
controlflow::trans_block(bcx, blk, dest)
|
|
}
|
|
ast::ExprStruct(_, ref fields, base) => {
|
|
trans_rec_or_struct(bcx,
|
|
fields.as_slice(),
|
|
base,
|
|
expr.span,
|
|
expr.id,
|
|
dest)
|
|
}
|
|
ast::ExprTup(ref args) => {
|
|
let repr = adt::represent_type(bcx.ccx(), expr_ty(bcx, expr));
|
|
let numbered_fields: Vec<(uint, @ast::Expr)> =
|
|
args.iter().enumerate().map(|(i, arg)| (i, *arg)).collect();
|
|
trans_adt(bcx, &*repr, 0, numbered_fields.as_slice(), None, dest)
|
|
}
|
|
ast::ExprLit(lit) => {
|
|
match lit.node {
|
|
ast::LitStr(ref s, _) => {
|
|
tvec::trans_lit_str(bcx, expr, (*s).clone(), dest)
|
|
}
|
|
_ => {
|
|
bcx.tcx()
|
|
.sess
|
|
.span_bug(expr.span,
|
|
"trans_rvalue_dps_unadjusted shouldn't be \
|
|
translating this type of literal")
|
|
}
|
|
}
|
|
}
|
|
ast::ExprVstore(contents, ast::ExprVstoreSlice) |
|
|
ast::ExprVstore(contents, ast::ExprVstoreMutSlice) => {
|
|
fcx.push_ast_cleanup_scope(contents.id);
|
|
bcx = tvec::trans_slice_vstore(bcx, expr, contents, dest);
|
|
fcx.pop_and_trans_ast_cleanup_scope(bcx, contents.id)
|
|
}
|
|
ast::ExprVec(..) | ast::ExprRepeat(..) => {
|
|
tvec::trans_fixed_vstore(bcx, expr, expr, dest)
|
|
}
|
|
ast::ExprFnBlock(decl, body) |
|
|
ast::ExprProc(decl, body) => {
|
|
let expr_ty = expr_ty(bcx, expr);
|
|
let store = ty::ty_closure_store(expr_ty);
|
|
debug!("translating block function {} with type {}",
|
|
expr_to_str(expr), expr_ty.repr(tcx));
|
|
closure::trans_expr_fn(bcx, store, decl, body, expr.id, dest)
|
|
}
|
|
ast::ExprCall(f, ref args) => {
|
|
callee::trans_call(bcx, expr, f, callee::ArgExprs(args.as_slice()), dest)
|
|
}
|
|
ast::ExprMethodCall(_, _, ref args) => {
|
|
callee::trans_method_call(bcx,
|
|
expr,
|
|
*args.get(0),
|
|
callee::ArgExprs(args.as_slice()),
|
|
dest)
|
|
}
|
|
ast::ExprBinary(_, lhs, rhs) => {
|
|
// if not overloaded, would be RvalueDatumExpr
|
|
let lhs = unpack_datum!(bcx, trans(bcx, lhs));
|
|
let rhs_datum = unpack_datum!(bcx, trans(bcx, rhs));
|
|
trans_overloaded_op(bcx, expr, MethodCall::expr(expr.id), lhs,
|
|
Some((rhs_datum, rhs.id)), Some(dest)).bcx
|
|
}
|
|
ast::ExprUnary(_, subexpr) => {
|
|
// if not overloaded, would be RvalueDatumExpr
|
|
let arg = unpack_datum!(bcx, trans(bcx, subexpr));
|
|
trans_overloaded_op(bcx, expr, MethodCall::expr(expr.id),
|
|
arg, None, Some(dest)).bcx
|
|
}
|
|
ast::ExprIndex(base, idx) => {
|
|
// if not overloaded, would be RvalueDatumExpr
|
|
let base = unpack_datum!(bcx, trans(bcx, base));
|
|
let idx_datum = unpack_datum!(bcx, trans(bcx, idx));
|
|
trans_overloaded_op(bcx, expr, MethodCall::expr(expr.id), base,
|
|
Some((idx_datum, idx.id)), Some(dest)).bcx
|
|
}
|
|
ast::ExprCast(val, _) => {
|
|
// DPS output mode means this is a trait cast:
|
|
match ty::get(node_id_type(bcx, expr.id)).sty {
|
|
ty::ty_trait(..) => {
|
|
let datum = unpack_datum!(bcx, trans(bcx, val));
|
|
meth::trans_trait_cast(bcx, datum, expr.id, dest)
|
|
}
|
|
_ => {
|
|
bcx.tcx().sess.span_bug(expr.span,
|
|
"expr_cast of non-trait");
|
|
}
|
|
}
|
|
}
|
|
ast::ExprAssignOp(op, dst, src) => {
|
|
trans_assign_op(bcx, expr, op, dst, src)
|
|
}
|
|
ast::ExprBox(_, contents) => {
|
|
// Special case for `Gc<T>` for now. The other case, for unique
|
|
// pointers, is handled in `trans_rvalue_datum_unadjusted`.
|
|
trans_gc(bcx, expr, contents, dest)
|
|
}
|
|
_ => {
|
|
bcx.tcx().sess.span_bug(
|
|
expr.span,
|
|
format!("trans_rvalue_dps_unadjusted reached fall-through case: {:?}",
|
|
expr.node));
|
|
}
|
|
}
|
|
}
|
|
|
|
fn trans_def_dps_unadjusted<'a>(
|
|
bcx: &'a Block<'a>,
|
|
ref_expr: &ast::Expr,
|
|
def: ast::Def,
|
|
dest: Dest)
|
|
-> &'a Block<'a> {
|
|
let _icx = push_ctxt("trans_def_dps_unadjusted");
|
|
|
|
let lldest = match dest {
|
|
SaveIn(lldest) => lldest,
|
|
Ignore => { return bcx; }
|
|
};
|
|
|
|
match def {
|
|
ast::DefVariant(tid, vid, _) => {
|
|
let variant_info = ty::enum_variant_with_id(bcx.tcx(), tid, vid);
|
|
if variant_info.args.len() > 0u {
|
|
// N-ary variant.
|
|
let llfn = callee::trans_fn_ref(bcx, vid, ExprId(ref_expr.id));
|
|
Store(bcx, llfn, lldest);
|
|
return bcx;
|
|
} else {
|
|
// Nullary variant.
|
|
let ty = expr_ty(bcx, ref_expr);
|
|
let repr = adt::represent_type(bcx.ccx(), ty);
|
|
adt::trans_start_init(bcx, &*repr, lldest,
|
|
variant_info.disr_val);
|
|
return bcx;
|
|
}
|
|
}
|
|
ast::DefStruct(_) => {
|
|
let ty = expr_ty(bcx, ref_expr);
|
|
match ty::get(ty).sty {
|
|
ty::ty_struct(did, _) if ty::has_dtor(bcx.tcx(), did) => {
|
|
let repr = adt::represent_type(bcx.ccx(), ty);
|
|
adt::trans_start_init(bcx, &*repr, lldest, 0);
|
|
}
|
|
_ => {}
|
|
}
|
|
bcx
|
|
}
|
|
_ => {
|
|
bcx.tcx().sess.span_bug(ref_expr.span, format!(
|
|
"Non-DPS def {:?} referened by {}",
|
|
def, bcx.node_id_to_str(ref_expr.id)));
|
|
}
|
|
}
|
|
}
|
|
|
|
fn trans_def_fn_unadjusted<'a>(bcx: &'a Block<'a>,
|
|
ref_expr: &ast::Expr,
|
|
def: ast::Def) -> DatumBlock<'a, Expr> {
|
|
let _icx = push_ctxt("trans_def_datum_unadjusted");
|
|
|
|
let llfn = match def {
|
|
ast::DefFn(did, _) |
|
|
ast::DefStruct(did) | ast::DefVariant(_, did, _) |
|
|
ast::DefStaticMethod(did, ast::FromImpl(_), _) => {
|
|
callee::trans_fn_ref(bcx, did, ExprId(ref_expr.id))
|
|
}
|
|
ast::DefStaticMethod(impl_did, ast::FromTrait(trait_did), _) => {
|
|
meth::trans_static_method_callee(bcx, impl_did,
|
|
trait_did, ref_expr.id)
|
|
}
|
|
_ => {
|
|
bcx.tcx().sess.span_bug(ref_expr.span, format!(
|
|
"trans_def_fn_unadjusted invoked on: {:?} for {}",
|
|
def,
|
|
ref_expr.repr(bcx.tcx())));
|
|
}
|
|
};
|
|
|
|
let fn_ty = expr_ty(bcx, ref_expr);
|
|
DatumBlock(bcx, Datum(llfn, fn_ty, RvalueExpr(Rvalue(ByValue))))
|
|
}
|
|
|
|
pub fn trans_local_var<'a>(bcx: &'a Block<'a>,
|
|
def: ast::Def)
|
|
-> Datum<Lvalue> {
|
|
/*!
|
|
* Translates a reference to a local variable or argument.
|
|
* This always results in an lvalue datum.
|
|
*/
|
|
|
|
let _icx = push_ctxt("trans_local_var");
|
|
|
|
return match def {
|
|
ast::DefUpvar(nid, _, _, _) => {
|
|
// Can't move upvars, so this is never a ZeroMemLastUse.
|
|
let local_ty = node_id_type(bcx, nid);
|
|
match bcx.fcx.llupvars.borrow().find(&nid) {
|
|
Some(&val) => Datum(val, local_ty, Lvalue),
|
|
None => {
|
|
bcx.sess().bug(format!(
|
|
"trans_local_var: no llval for upvar {:?} found", nid));
|
|
}
|
|
}
|
|
}
|
|
ast::DefArg(nid, _) => {
|
|
take_local(bcx, &*bcx.fcx.llargs.borrow(), nid)
|
|
}
|
|
ast::DefLocal(nid, _) | ast::DefBinding(nid, _) => {
|
|
take_local(bcx, &*bcx.fcx.lllocals.borrow(), nid)
|
|
}
|
|
_ => {
|
|
bcx.sess().unimpl(format!(
|
|
"unsupported def type in trans_local_var: {:?}", def));
|
|
}
|
|
};
|
|
|
|
fn take_local<'a>(bcx: &'a Block<'a>,
|
|
table: &NodeMap<Datum<Lvalue>>,
|
|
nid: ast::NodeId)
|
|
-> Datum<Lvalue> {
|
|
let datum = match table.find(&nid) {
|
|
Some(&v) => v,
|
|
None => {
|
|
bcx.sess().bug(format!(
|
|
"trans_local_var: no datum for local/arg {:?} found", nid));
|
|
}
|
|
};
|
|
debug!("take_local(nid={:?}, v={}, ty={})",
|
|
nid, bcx.val_to_str(datum.val), bcx.ty_to_str(datum.ty));
|
|
datum
|
|
}
|
|
}
|
|
|
|
pub fn with_field_tys<R>(tcx: &ty::ctxt,
|
|
ty: ty::t,
|
|
node_id_opt: Option<ast::NodeId>,
|
|
op: |ty::Disr, (&[ty::field])| -> R)
|
|
-> R {
|
|
/*!
|
|
* Helper for enumerating the field types of structs, enums, or records.
|
|
* The optional node ID here is the node ID of the path identifying the enum
|
|
* variant in use. If none, this cannot possibly an enum variant (so, if it
|
|
* is and `node_id_opt` is none, this function fails).
|
|
*/
|
|
|
|
match ty::get(ty).sty {
|
|
ty::ty_struct(did, ref substs) => {
|
|
op(0, struct_fields(tcx, did, substs).as_slice())
|
|
}
|
|
|
|
ty::ty_enum(_, ref substs) => {
|
|
// We want the *variant* ID here, not the enum ID.
|
|
match node_id_opt {
|
|
None => {
|
|
tcx.sess.bug(format!(
|
|
"cannot get field types from the enum type {} \
|
|
without a node ID",
|
|
ty.repr(tcx)));
|
|
}
|
|
Some(node_id) => {
|
|
let def = tcx.def_map.borrow().get_copy(&node_id);
|
|
match def {
|
|
ast::DefVariant(enum_id, variant_id, _) => {
|
|
let variant_info = ty::enum_variant_with_id(
|
|
tcx, enum_id, variant_id);
|
|
op(variant_info.disr_val,
|
|
struct_fields(tcx,
|
|
variant_id,
|
|
substs).as_slice())
|
|
}
|
|
_ => {
|
|
tcx.sess.bug("resolve didn't map this expr to a \
|
|
variant ID")
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
_ => {
|
|
tcx.sess.bug(format!(
|
|
"cannot get field types from the type {}",
|
|
ty.repr(tcx)));
|
|
}
|
|
}
|
|
}
|
|
|
|
fn trans_rec_or_struct<'a>(
|
|
bcx: &'a Block<'a>,
|
|
fields: &[ast::Field],
|
|
base: Option<@ast::Expr>,
|
|
expr_span: codemap::Span,
|
|
id: ast::NodeId,
|
|
dest: Dest)
|
|
-> &'a Block<'a> {
|
|
let _icx = push_ctxt("trans_rec");
|
|
let bcx = bcx;
|
|
|
|
let ty = node_id_type(bcx, id);
|
|
let tcx = bcx.tcx();
|
|
with_field_tys(tcx, ty, Some(id), |discr, field_tys| {
|
|
let mut need_base = Vec::from_elem(field_tys.len(), true);
|
|
|
|
let numbered_fields = fields.iter().map(|field| {
|
|
let opt_pos =
|
|
field_tys.iter().position(|field_ty|
|
|
field_ty.ident.name == field.ident.node.name);
|
|
match opt_pos {
|
|
Some(i) => {
|
|
*need_base.get_mut(i) = false;
|
|
(i, field.expr)
|
|
}
|
|
None => {
|
|
tcx.sess.span_bug(field.span,
|
|
"Couldn't find field in struct type")
|
|
}
|
|
}
|
|
}).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, field_tys[i].mt.ty))
|
|
}
|
|
}
|
|
Some(StructBaseInfo {expr: base_expr,
|
|
fields: leftovers })
|
|
}
|
|
None => {
|
|
if need_base.iter().any(|b| *b) {
|
|
tcx.sess.span_bug(expr_span, "missing fields and no base expr")
|
|
}
|
|
None
|
|
}
|
|
};
|
|
|
|
let repr = adt::represent_type(bcx.ccx(), ty);
|
|
trans_adt(bcx, &*repr, discr, numbered_fields.as_slice(), optbase, dest)
|
|
})
|
|
}
|
|
|
|
/**
|
|
* 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.
|
|
*/
|
|
struct StructBaseInfo {
|
|
/// The base expression; will be evaluated after all explicit fields.
|
|
expr: @ast::Expr,
|
|
/// The indices of fields to copy paired with their types.
|
|
fields: Vec<(uint, ty::t)> }
|
|
|
|
/**
|
|
* 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`.
|
|
*/
|
|
fn trans_adt<'a>(
|
|
bcx: &'a Block<'a>,
|
|
repr: &adt::Repr,
|
|
discr: ty::Disr,
|
|
fields: &[(uint, @ast::Expr)],
|
|
optbase: Option<StructBaseInfo>,
|
|
dest: Dest)
|
|
-> &'a Block<'a> {
|
|
let _icx = push_ctxt("trans_adt");
|
|
let fcx = bcx.fcx;
|
|
let mut bcx = bcx;
|
|
let addr = match dest {
|
|
Ignore => {
|
|
for &(_i, e) in fields.iter() {
|
|
bcx = trans_into(bcx, e, Ignore);
|
|
}
|
|
for sbi in optbase.iter() {
|
|
// FIXME #7261: this moves entire base, not just certain fields
|
|
bcx = trans_into(bcx, sbi.expr, Ignore);
|
|
}
|
|
return bcx;
|
|
}
|
|
SaveIn(pos) => pos
|
|
};
|
|
|
|
// This scope holds intermediates that must be cleaned should
|
|
// failure occur before the ADT as a whole is ready.
|
|
let custom_cleanup_scope = fcx.push_custom_cleanup_scope();
|
|
|
|
adt::trans_start_init(bcx, repr, addr, discr);
|
|
|
|
for &(i, e) in fields.iter() {
|
|
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));
|
|
fcx.schedule_drop_mem(cleanup::CustomScope(custom_cleanup_scope),
|
|
dest, e_ty);
|
|
}
|
|
|
|
for base in optbase.iter() {
|
|
// FIXME #6573: is it sound to use the destination's repr on the base?
|
|
// And, would it ever be reasonable to be here with discr != 0?
|
|
let base_datum = unpack_datum!(bcx, trans_to_lvalue(bcx, base.expr, "base"));
|
|
for &(i, t) in base.fields.iter() {
|
|
let datum = base_datum.get_element(
|
|
t,
|
|
|srcval| adt::trans_field_ptr(bcx, repr, srcval, discr, i));
|
|
let dest = adt::trans_field_ptr(bcx, repr, addr, discr, i);
|
|
bcx = datum.store_to(bcx, dest);
|
|
}
|
|
}
|
|
|
|
fcx.pop_custom_cleanup_scope(custom_cleanup_scope);
|
|
|
|
return bcx;
|
|
}
|
|
|
|
|
|
fn trans_immediate_lit<'a>(bcx: &'a Block<'a>,
|
|
expr: &ast::Expr,
|
|
lit: ast::Lit)
|
|
-> DatumBlock<'a, 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<'a>(bcx: &'a Block<'a>,
|
|
expr: &ast::Expr,
|
|
op: ast::UnOp,
|
|
sub_expr: &ast::Expr)
|
|
-> DatumBlock<'a, 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 == ast::UnDeref ||
|
|
!ccx.tcx.method_map.borrow().contains_key(&method_call));
|
|
|
|
let un_ty = expr_ty(bcx, expr);
|
|
|
|
match op {
|
|
ast::UnNot => {
|
|
let datum = unpack_datum!(bcx, trans(bcx, sub_expr));
|
|
let llresult = if ty::type_is_bool(un_ty) {
|
|
let val = datum.to_llscalarish(bcx);
|
|
let llcond = ICmp(bcx,
|
|
lib::llvm::IntEQ,
|
|
val,
|
|
C_bool(ccx, false));
|
|
Select(bcx, llcond, C_bool(ccx, true), C_bool(ccx, false))
|
|
} else {
|
|
// Note: `Not` is bitwise, not suitable for logical not.
|
|
Not(bcx, datum.to_llscalarish(bcx))
|
|
};
|
|
immediate_rvalue_bcx(bcx, llresult, un_ty).to_expr_datumblock()
|
|
}
|
|
ast::UnNeg => {
|
|
let datum = unpack_datum!(bcx, trans(bcx, sub_expr));
|
|
let val = datum.to_llscalarish(bcx);
|
|
let llneg = {
|
|
if ty::type_is_fp(un_ty) {
|
|
FNeg(bcx, val)
|
|
} else {
|
|
Neg(bcx, val)
|
|
}
|
|
};
|
|
immediate_rvalue_bcx(bcx, llneg, un_ty).to_expr_datumblock()
|
|
}
|
|
ast::UnBox => {
|
|
trans_managed_expr(bcx, un_ty, sub_expr, expr_ty(bcx, sub_expr))
|
|
}
|
|
ast::UnUniq => {
|
|
trans_uniq_expr(bcx, un_ty, sub_expr, expr_ty(bcx, sub_expr))
|
|
}
|
|
ast::UnDeref => {
|
|
let datum = unpack_datum!(bcx, trans(bcx, sub_expr));
|
|
deref_once(bcx, expr, datum, 0)
|
|
}
|
|
}
|
|
}
|
|
|
|
fn trans_uniq_expr<'a>(bcx: &'a Block<'a>,
|
|
box_ty: ty::t,
|
|
contents: &ast::Expr,
|
|
contents_ty: ty::t)
|
|
-> DatumBlock<'a, Expr> {
|
|
let _icx = push_ctxt("trans_uniq_expr");
|
|
let fcx = bcx.fcx;
|
|
let llty = type_of::type_of(bcx.ccx(), contents_ty);
|
|
let size = llsize_of(bcx.ccx(), llty);
|
|
let align = C_uint(bcx.ccx(), llalign_of_min(bcx.ccx(), llty) as uint);
|
|
// We need to a make a pointer type because box_ty is ty_bot
|
|
// if content_ty is, e.g. box fail!().
|
|
let real_box_ty = ty::mk_uniq(bcx.tcx(), contents_ty);
|
|
let Result { bcx, val } = malloc_raw_dyn(bcx, real_box_ty, size, align);
|
|
// 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_managed_expr<'a>(bcx: &'a Block<'a>,
|
|
box_ty: ty::t,
|
|
contents: &ast::Expr,
|
|
contents_ty: ty::t)
|
|
-> DatumBlock<'a, Expr> {
|
|
let _icx = push_ctxt("trans_managed_expr");
|
|
let fcx = bcx.fcx;
|
|
let ty = type_of::type_of(bcx.ccx(), contents_ty);
|
|
let Result {bcx, val: bx} = malloc_raw_dyn_managed(bcx, contents_ty, MallocFnLangItem,
|
|
llsize_of(bcx.ccx(), ty));
|
|
let body = GEPi(bcx, bx, [0u, abi::box_field_body]);
|
|
|
|
let custom_cleanup_scope = fcx.push_custom_cleanup_scope();
|
|
fcx.schedule_free_value(cleanup::CustomScope(custom_cleanup_scope),
|
|
bx, cleanup::HeapManaged, contents_ty);
|
|
let bcx = trans_into(bcx, contents, SaveIn(body));
|
|
fcx.pop_custom_cleanup_scope(custom_cleanup_scope);
|
|
immediate_rvalue_bcx(bcx, bx, box_ty).to_expr_datumblock()
|
|
}
|
|
|
|
fn trans_addr_of<'a>(bcx: &'a Block<'a>,
|
|
expr: &ast::Expr,
|
|
subexpr: &ast::Expr)
|
|
-> DatumBlock<'a, 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);
|
|
return immediate_rvalue_bcx(bcx, sub_datum.val, ty).to_expr_datumblock();
|
|
}
|
|
|
|
fn trans_gc<'a>(mut bcx: &'a Block<'a>,
|
|
expr: &ast::Expr,
|
|
contents: &ast::Expr,
|
|
dest: Dest)
|
|
-> &'a Block<'a> {
|
|
let contents_ty = expr_ty(bcx, contents);
|
|
let box_ty = ty::mk_box(bcx.tcx(), contents_ty);
|
|
|
|
let contents_datum = unpack_datum!(bcx, trans_managed_expr(bcx,
|
|
box_ty,
|
|
contents,
|
|
contents_ty));
|
|
|
|
match dest {
|
|
Ignore => bcx,
|
|
SaveIn(addr) => {
|
|
let expr_ty = expr_ty(bcx, expr);
|
|
let repr = adt::represent_type(bcx.ccx(), expr_ty);
|
|
adt::trans_start_init(bcx, &*repr, addr, 0);
|
|
let field_dest = adt::trans_field_ptr(bcx, &*repr, addr, 0, 0);
|
|
contents_datum.store_to(bcx, field_dest)
|
|
}
|
|
}
|
|
}
|
|
|
|
// Important to get types for both lhs and rhs, because one might be _|_
|
|
// and the other not.
|
|
fn trans_eager_binop<'a>(
|
|
bcx: &'a Block<'a>,
|
|
binop_expr: &ast::Expr,
|
|
binop_ty: ty::t,
|
|
op: ast::BinOp,
|
|
lhs_t: ty::t,
|
|
lhs: ValueRef,
|
|
rhs_t: ty::t,
|
|
rhs: ValueRef)
|
|
-> DatumBlock<'a, Expr> {
|
|
let _icx = push_ctxt("trans_eager_binop");
|
|
|
|
let tcx = bcx.tcx();
|
|
let is_simd = ty::type_is_simd(tcx, lhs_t);
|
|
let intype = {
|
|
if ty::type_is_bot(lhs_t) { rhs_t }
|
|
else if is_simd { ty::simd_type(tcx, lhs_t) }
|
|
else { lhs_t }
|
|
};
|
|
let is_float = ty::type_is_fp(intype);
|
|
let is_signed = ty::type_is_signed(intype);
|
|
|
|
let rhs = base::cast_shift_expr_rhs(bcx, op, lhs, rhs);
|
|
|
|
let mut bcx = bcx;
|
|
let val = match op {
|
|
ast::BiAdd => {
|
|
if is_float { FAdd(bcx, lhs, rhs) }
|
|
else { Add(bcx, lhs, rhs) }
|
|
}
|
|
ast::BiSub => {
|
|
if is_float { FSub(bcx, lhs, rhs) }
|
|
else { Sub(bcx, lhs, rhs) }
|
|
}
|
|
ast::BiMul => {
|
|
if is_float { FMul(bcx, lhs, rhs) }
|
|
else { Mul(bcx, lhs, rhs) }
|
|
}
|
|
ast::BiDiv => {
|
|
if is_float {
|
|
FDiv(bcx, lhs, rhs)
|
|
} else {
|
|
// Only zero-check integers; fp /0 is NaN
|
|
bcx = base::fail_if_zero(bcx, binop_expr.span,
|
|
op, rhs, rhs_t);
|
|
if is_signed {
|
|
SDiv(bcx, lhs, rhs)
|
|
} else {
|
|
UDiv(bcx, lhs, rhs)
|
|
}
|
|
}
|
|
}
|
|
ast::BiRem => {
|
|
if is_float {
|
|
FRem(bcx, lhs, rhs)
|
|
} else {
|
|
// Only zero-check integers; fp %0 is NaN
|
|
bcx = base::fail_if_zero(bcx, binop_expr.span,
|
|
op, rhs, rhs_t);
|
|
if is_signed {
|
|
SRem(bcx, lhs, rhs)
|
|
} else {
|
|
URem(bcx, lhs, rhs)
|
|
}
|
|
}
|
|
}
|
|
ast::BiBitOr => Or(bcx, lhs, rhs),
|
|
ast::BiBitAnd => And(bcx, lhs, rhs),
|
|
ast::BiBitXor => Xor(bcx, lhs, rhs),
|
|
ast::BiShl => Shl(bcx, lhs, rhs),
|
|
ast::BiShr => {
|
|
if is_signed {
|
|
AShr(bcx, lhs, rhs)
|
|
} else { LShr(bcx, lhs, rhs) }
|
|
}
|
|
ast::BiEq | ast::BiNe | ast::BiLt | ast::BiGe | ast::BiLe | ast::BiGt => {
|
|
if ty::type_is_bot(rhs_t) {
|
|
C_bool(bcx.ccx(), false)
|
|
} else if ty::type_is_scalar(rhs_t) {
|
|
let cmpr = base::compare_scalar_types(bcx, lhs, rhs, rhs_t, op);
|
|
bcx = cmpr.bcx;
|
|
ZExt(bcx, cmpr.val, Type::i8(bcx.ccx()))
|
|
} else if is_simd {
|
|
base::compare_simd_types(bcx, lhs, rhs, intype, ty::simd_size(tcx, lhs_t), op)
|
|
} else {
|
|
bcx.tcx().sess.span_bug(binop_expr.span, "comparison operator unsupported for type")
|
|
}
|
|
}
|
|
_ => {
|
|
bcx.tcx().sess.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
|
|
enum lazy_binop_ty {
|
|
lazy_and,
|
|
lazy_or,
|
|
}
|
|
|
|
fn trans_lazy_binop<'a>(
|
|
bcx: &'a Block<'a>,
|
|
binop_expr: &ast::Expr,
|
|
op: lazy_binop_ty,
|
|
a: &ast::Expr,
|
|
b: &ast::Expr)
|
|
-> DatumBlock<'a, 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();
|
|
}
|
|
|
|
let join = fcx.new_id_block("join", binop_expr.id);
|
|
let before_rhs = fcx.new_id_block("before_rhs", b.id);
|
|
|
|
let lhs_i1 = bool_to_i1(past_lhs, lhs);
|
|
match op {
|
|
lazy_and => CondBr(past_lhs, lhs_i1, before_rhs.llbb, join.llbb),
|
|
lazy_or => CondBr(past_lhs, lhs_i1, join.llbb, before_rhs.llbb)
|
|
}
|
|
|
|
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);
|
|
let phi = Phi(join, Type::bool(bcx.ccx()), [lhs, rhs],
|
|
[past_lhs.llbb, past_rhs.llbb]);
|
|
|
|
return immediate_rvalue_bcx(join, phi, binop_ty).to_expr_datumblock();
|
|
}
|
|
|
|
fn trans_binary<'a>(bcx: &'a Block<'a>,
|
|
expr: &ast::Expr,
|
|
op: ast::BinOp,
|
|
lhs: &ast::Expr,
|
|
rhs: &ast::Expr)
|
|
-> DatumBlock<'a, Expr> {
|
|
let _icx = push_ctxt("trans_binary");
|
|
let ccx = bcx.ccx();
|
|
|
|
// if overloaded, would be RvalueDpsExpr
|
|
assert!(!ccx.tcx.method_map.borrow().contains_key(&MethodCall::expr(expr.id)));
|
|
|
|
match op {
|
|
ast::BiAnd => {
|
|
trans_lazy_binop(bcx, expr, lazy_and, lhs, rhs)
|
|
}
|
|
ast::BiOr => {
|
|
trans_lazy_binop(bcx, expr, lazy_or, lhs, rhs)
|
|
}
|
|
_ => {
|
|
let mut bcx = bcx;
|
|
let lhs_datum = unpack_datum!(bcx, trans(bcx, lhs));
|
|
let rhs_datum = unpack_datum!(bcx, trans(bcx, rhs));
|
|
let binop_ty = expr_ty(bcx, expr);
|
|
|
|
debug!("trans_binary (expr {}): lhs_datum={}",
|
|
expr.id,
|
|
lhs_datum.to_str(ccx));
|
|
let lhs_ty = lhs_datum.ty;
|
|
let lhs = lhs_datum.to_llscalarish(bcx);
|
|
|
|
debug!("trans_binary (expr {}): rhs_datum={}",
|
|
expr.id,
|
|
rhs_datum.to_str(ccx));
|
|
let rhs_ty = rhs_datum.ty;
|
|
let rhs = rhs_datum.to_llscalarish(bcx);
|
|
trans_eager_binop(bcx, expr, binop_ty, op,
|
|
lhs_ty, lhs, rhs_ty, rhs)
|
|
}
|
|
}
|
|
}
|
|
|
|
fn trans_overloaded_op<'a, 'b>(
|
|
bcx: &'a Block<'a>,
|
|
expr: &ast::Expr,
|
|
method_call: MethodCall,
|
|
lhs: Datum<Expr>,
|
|
rhs: Option<(Datum<Expr>, ast::NodeId)>,
|
|
dest: Option<Dest>)
|
|
-> Result<'a> {
|
|
let method_ty = bcx.tcx().method_map.borrow().get(&method_call).ty;
|
|
callee::trans_call_inner(bcx,
|
|
Some(expr_info(expr)),
|
|
monomorphize_type(bcx, method_ty),
|
|
|bcx, arg_cleanup_scope| {
|
|
meth::trans_method_callee(bcx,
|
|
method_call,
|
|
None,
|
|
arg_cleanup_scope)
|
|
},
|
|
callee::ArgOverloadedOp(lhs, rhs),
|
|
dest)
|
|
}
|
|
|
|
fn int_cast(bcx: &Block,
|
|
lldsttype: Type,
|
|
llsrctype: Type,
|
|
llsrc: ValueRef,
|
|
signed: bool)
|
|
-> ValueRef {
|
|
let _icx = push_ctxt("int_cast");
|
|
unsafe {
|
|
let srcsz = llvm::LLVMGetIntTypeWidth(llsrctype.to_ref());
|
|
let dstsz = llvm::LLVMGetIntTypeWidth(lldsttype.to_ref());
|
|
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 };
|
|
}
|
|
|
|
#[deriving(Eq)]
|
|
pub enum cast_kind {
|
|
cast_pointer,
|
|
cast_integral,
|
|
cast_float,
|
|
cast_enum,
|
|
cast_other,
|
|
}
|
|
|
|
pub fn cast_type_kind(t: ty::t) -> cast_kind {
|
|
match ty::get(t).sty {
|
|
ty::ty_char => cast_integral,
|
|
ty::ty_float(..) => cast_float,
|
|
ty::ty_ptr(..) => cast_pointer,
|
|
ty::ty_rptr(_, mt) => match ty::get(mt.ty).sty{
|
|
ty::ty_vec(_, None) | ty::ty_str => cast_other,
|
|
_ => cast_pointer,
|
|
},
|
|
ty::ty_bare_fn(..) => cast_pointer,
|
|
ty::ty_int(..) => cast_integral,
|
|
ty::ty_uint(..) => cast_integral,
|
|
ty::ty_bool => cast_integral,
|
|
ty::ty_enum(..) => cast_enum,
|
|
_ => cast_other
|
|
}
|
|
}
|
|
|
|
fn trans_imm_cast<'a>(bcx: &'a Block<'a>,
|
|
expr: &ast::Expr,
|
|
id: ast::NodeId)
|
|
-> DatumBlock<'a, Expr> {
|
|
let _icx = push_ctxt("trans_cast");
|
|
let mut bcx = bcx;
|
|
let ccx = bcx.ccx();
|
|
|
|
let t_in = expr_ty(bcx, expr);
|
|
let t_out = node_id_type(bcx, id);
|
|
let k_in = cast_type_kind(t_in);
|
|
let k_out = cast_type_kind(t_out);
|
|
let s_in = k_in == cast_integral && ty::type_is_signed(t_in);
|
|
let ll_t_in = type_of::type_of(ccx, t_in);
|
|
let ll_t_out = type_of::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 datum = unpack_datum!(bcx, trans(bcx, expr));
|
|
let newval = match (k_in, k_out) {
|
|
(cast_integral, cast_integral) => {
|
|
let llexpr = datum.to_llscalarish(bcx);
|
|
int_cast(bcx, ll_t_out, ll_t_in, llexpr, s_in)
|
|
}
|
|
(cast_float, cast_float) => {
|
|
let llexpr = datum.to_llscalarish(bcx);
|
|
float_cast(bcx, ll_t_out, ll_t_in, llexpr)
|
|
}
|
|
(cast_integral, cast_float) => {
|
|
let llexpr = datum.to_llscalarish(bcx);
|
|
if s_in {
|
|
SIToFP(bcx, llexpr, ll_t_out)
|
|
} else { UIToFP(bcx, llexpr, ll_t_out) }
|
|
}
|
|
(cast_float, cast_integral) => {
|
|
let llexpr = datum.to_llscalarish(bcx);
|
|
if ty::type_is_signed(t_out) {
|
|
FPToSI(bcx, llexpr, ll_t_out)
|
|
} else { FPToUI(bcx, llexpr, ll_t_out) }
|
|
}
|
|
(cast_integral, cast_pointer) => {
|
|
let llexpr = datum.to_llscalarish(bcx);
|
|
IntToPtr(bcx, llexpr, ll_t_out)
|
|
}
|
|
(cast_pointer, cast_integral) => {
|
|
let llexpr = datum.to_llscalarish(bcx);
|
|
PtrToInt(bcx, llexpr, ll_t_out)
|
|
}
|
|
(cast_pointer, cast_pointer) => {
|
|
let llexpr = datum.to_llscalarish(bcx);
|
|
PointerCast(bcx, llexpr, ll_t_out)
|
|
}
|
|
(cast_enum, cast_integral) |
|
|
(cast_enum, cast_float) => {
|
|
let mut bcx = bcx;
|
|
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 lldiscrim_a =
|
|
adt::trans_get_discr(bcx, &*repr, llexpr_ptr, Some(Type::i64(ccx)));
|
|
match k_out {
|
|
cast_integral => int_cast(bcx, ll_t_out,
|
|
val_ty(lldiscrim_a),
|
|
lldiscrim_a, true),
|
|
cast_float => SIToFP(bcx, lldiscrim_a, ll_t_out),
|
|
_ => ccx.sess().bug(format!("translating unsupported cast: \
|
|
{} ({:?}) -> {} ({:?})",
|
|
t_in.repr(bcx.tcx()), k_in,
|
|
t_out.repr(bcx.tcx()), k_out))
|
|
}
|
|
}
|
|
_ => ccx.sess().bug(format!("translating unsupported cast: \
|
|
{} ({:?}) -> {} ({:?})",
|
|
t_in.repr(bcx.tcx()), k_in,
|
|
t_out.repr(bcx.tcx()), k_out))
|
|
};
|
|
return immediate_rvalue_bcx(bcx, newval, t_out).to_expr_datumblock();
|
|
}
|
|
|
|
fn trans_assign_op<'a>(
|
|
bcx: &'a Block<'a>,
|
|
expr: &ast::Expr,
|
|
op: ast::BinOp,
|
|
dst: &ast::Expr,
|
|
src: @ast::Expr)
|
|
-> &'a Block<'a> {
|
|
let _icx = push_ctxt("trans_assign_op");
|
|
let mut bcx = bcx;
|
|
|
|
debug!("trans_assign_op(expr={})", bcx.expr_to_str(expr));
|
|
|
|
// User-defined operator methods cannot be used with `+=` etc right now
|
|
assert!(!bcx.tcx().method_map.borrow().contains_key(&MethodCall::expr(expr.id)));
|
|
|
|
// Evaluate LHS (destination), which should be an lvalue
|
|
let dst_datum = unpack_datum!(bcx, trans_to_lvalue(bcx, dst, "assign_op"));
|
|
assert!(!ty::type_needs_drop(bcx.tcx(), dst_datum.ty));
|
|
let dst_ty = dst_datum.ty;
|
|
let dst = Load(bcx, dst_datum.val);
|
|
|
|
// Evaluate RHS
|
|
let rhs_datum = unpack_datum!(bcx, trans(bcx, src));
|
|
let rhs_ty = rhs_datum.ty;
|
|
let rhs = rhs_datum.to_llscalarish(bcx);
|
|
|
|
// Perform computation and store the result
|
|
let result_datum = unpack_datum!(
|
|
bcx, trans_eager_binop(bcx, expr, dst_datum.ty, op,
|
|
dst_ty, dst, rhs_ty, rhs));
|
|
return result_datum.store_to(bcx, dst_datum.val);
|
|
}
|
|
|
|
fn auto_ref<'a>(bcx: &'a Block<'a>,
|
|
datum: Datum<Expr>,
|
|
expr: &ast::Expr)
|
|
-> DatumBlock<'a, 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 = ty::mk_imm_rptr(bcx.tcx(), ty::ReStatic, referent_ty);
|
|
|
|
// Get the pointer.
|
|
let llref = lv_datum.to_llref();
|
|
|
|
// Construct the resulting datum, using what was the "by ref"
|
|
// ValueRef of type `referent_ty` to be the "by value" ValueRef
|
|
// of type `&referent_ty`.
|
|
DatumBlock(bcx, Datum(llref, ptr_ty, RvalueExpr(Rvalue(ByValue))))
|
|
}
|
|
|
|
fn deref_multiple<'a>(bcx: &'a Block<'a>,
|
|
expr: &ast::Expr,
|
|
datum: Datum<Expr>,
|
|
times: uint)
|
|
-> DatumBlock<'a, Expr> {
|
|
let mut bcx = bcx;
|
|
let mut datum = datum;
|
|
for i in range(1, times+1) {
|
|
datum = unpack_datum!(bcx, deref_once(bcx, expr, datum, i));
|
|
}
|
|
DatumBlock { bcx: bcx, datum: datum }
|
|
}
|
|
|
|
fn deref_once<'a>(bcx: &'a Block<'a>,
|
|
expr: &ast::Expr,
|
|
datum: Datum<Expr>,
|
|
derefs: uint)
|
|
-> DatumBlock<'a, Expr> {
|
|
let ccx = bcx.ccx();
|
|
|
|
debug!("deref_once(expr={}, datum={}, derefs={})",
|
|
expr.repr(bcx.tcx()),
|
|
datum.to_str(ccx),
|
|
derefs);
|
|
|
|
let mut bcx = bcx;
|
|
|
|
// Check for overloaded deref.
|
|
let method_call = MethodCall {
|
|
expr_id: expr.id,
|
|
autoderef: derefs as u32
|
|
};
|
|
let method_ty = ccx.tcx.method_map.borrow()
|
|
.find(&method_call).map(|method| method.ty);
|
|
let datum = match method_ty {
|
|
Some(method_ty) => {
|
|
// Overloaded. Evaluate `trans_overloaded_op`, which will
|
|
// invoke the user's deref() method, which basically
|
|
// converts from the `Shaht<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 derefs == 0 {
|
|
datum
|
|
} else {
|
|
// Always perform an AutoPtr when applying an overloaded auto-deref.
|
|
unpack_datum!(bcx, auto_ref(bcx, datum, expr))
|
|
};
|
|
let val = unpack_result!(bcx, trans_overloaded_op(bcx, expr, method_call,
|
|
datum, None, None));
|
|
let ref_ty = ty::ty_fn_ret(monomorphize_type(bcx, method_ty));
|
|
Datum(val, ref_ty, RvalueExpr(Rvalue(ByValue)))
|
|
}
|
|
None => {
|
|
// Not overloaded. We already have a pointer we know how to deref.
|
|
datum
|
|
}
|
|
};
|
|
|
|
let r = match ty::get(datum.ty).sty {
|
|
ty::ty_uniq(content_ty) => {
|
|
match ty::get(content_ty).sty {
|
|
ty::ty_vec(_, None) | ty::ty_str
|
|
=> bcx.tcx().sess.span_bug(expr.span, "unexpected ~[T]"),
|
|
_ => deref_owned_pointer(bcx, expr, datum, content_ty),
|
|
}
|
|
}
|
|
|
|
ty::ty_box(content_ty) => {
|
|
let datum = unpack_datum!(
|
|
bcx, datum.to_lvalue_datum(bcx, "deref", expr.id));
|
|
let llptrref = datum.to_llref();
|
|
let llptr = Load(bcx, llptrref);
|
|
let llbody = GEPi(bcx, llptr, [0u, abi::box_field_body]);
|
|
DatumBlock(bcx, Datum(llbody, content_ty, LvalueExpr))
|
|
}
|
|
|
|
ty::ty_ptr(ty::mt { ty: content_ty, .. }) |
|
|
ty::ty_rptr(_, ty::mt { ty: content_ty, .. }) => {
|
|
match ty::get(content_ty).sty {
|
|
ty::ty_vec(_, None) | ty::ty_str
|
|
=> bcx.tcx().sess.span_bug(expr.span, "unexpected &[T]"),
|
|
_ => {
|
|
assert!(!ty::type_needs_drop(bcx.tcx(), datum.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(bcx, Datum(ptr, content_ty, LvalueExpr))
|
|
}
|
|
}
|
|
}
|
|
|
|
_ => {
|
|
bcx.tcx().sess.span_bug(
|
|
expr.span,
|
|
format!("deref invoked on expr of illegal type {}",
|
|
datum.ty.repr(bcx.tcx())));
|
|
}
|
|
};
|
|
|
|
debug!("deref_once(expr={}, derefs={}, result={})",
|
|
expr.id, derefs, r.datum.to_str(ccx));
|
|
|
|
return r;
|
|
|
|
fn deref_owned_pointer<'a>(bcx: &'a Block<'a>,
|
|
expr: &ast::Expr,
|
|
datum: Datum<Expr>,
|
|
content_ty: ty::t)
|
|
-> DatumBlock<'a, Expr> {
|
|
/*!
|
|
* We microoptimize derefs of owned pointers a bit here.
|
|
* Basically, the idea is to make the deref of an rvalue
|
|
* result in an rvalue. This helps to avoid intermediate stack
|
|
* slots in the resulting LLVM. The idea here is that, if the
|
|
* `Box<T>` pointer is an rvalue, then we can schedule a *shallow*
|
|
* free of the `Box<T>` pointer, and then return a ByRef rvalue
|
|
* into the pointer. Because the free is shallow, it is legit
|
|
* to return an rvalue, because we know that the contents are
|
|
* not yet scheduled to be freed. The language rules ensure that the
|
|
* contents will be used (or moved) before the free occurs.
|
|
*/
|
|
|
|
match datum.kind {
|
|
RvalueExpr(Rvalue { mode: ByRef }) => {
|
|
let scope = cleanup::temporary_scope(bcx.tcx(), expr.id);
|
|
let ptr = Load(bcx, datum.val);
|
|
if !type_is_zero_size(bcx.ccx(), content_ty) {
|
|
bcx.fcx.schedule_free_value(scope, ptr, cleanup::HeapExchange, content_ty);
|
|
}
|
|
}
|
|
RvalueExpr(Rvalue { mode: ByValue }) => {
|
|
let scope = cleanup::temporary_scope(bcx.tcx(), expr.id);
|
|
if !type_is_zero_size(bcx.ccx(), content_ty) {
|
|
bcx.fcx.schedule_free_value(scope, datum.val, cleanup::HeapExchange,
|
|
content_ty);
|
|
}
|
|
}
|
|
LvalueExpr => { }
|
|
}
|
|
|
|
// If we had an rvalue in, we produce an rvalue out.
|
|
let (llptr, kind) = match datum.kind {
|
|
LvalueExpr => {
|
|
(Load(bcx, datum.val), LvalueExpr)
|
|
}
|
|
RvalueExpr(Rvalue { mode: ByRef }) => {
|
|
(Load(bcx, datum.val), RvalueExpr(Rvalue(ByRef)))
|
|
}
|
|
RvalueExpr(Rvalue { mode: ByValue }) => {
|
|
(datum.val, RvalueExpr(Rvalue(ByRef)))
|
|
}
|
|
};
|
|
|
|
let datum = Datum { ty: content_ty, val: llptr, kind: kind };
|
|
DatumBlock { bcx: bcx, datum: datum }
|
|
}
|
|
}
|