931 lines
39 KiB
Rust
931 lines
39 KiB
Rust
// Copyright 2012 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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use back::abi;
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use llvm;
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use llvm::{ConstFCmp, ConstICmp, SetLinkage, SetUnnamedAddr};
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use llvm::{InternalLinkage, ValueRef, Bool, True};
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use middle::{check_const, def};
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use middle::const_eval::{self, ConstVal};
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use middle::const_eval::{const_int_checked_neg, const_uint_checked_neg};
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use middle::const_eval::{const_int_checked_add, const_uint_checked_add};
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use middle::const_eval::{const_int_checked_sub, const_uint_checked_sub};
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use middle::const_eval::{const_int_checked_mul, const_uint_checked_mul};
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use middle::const_eval::{const_int_checked_div, const_uint_checked_div};
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use middle::const_eval::{const_int_checked_rem, const_uint_checked_rem};
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use middle::const_eval::{const_int_checked_shl, const_uint_checked_shl};
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use middle::const_eval::{const_int_checked_shr, const_uint_checked_shr};
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use trans::{adt, closure, debuginfo, expr, inline, machine};
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use trans::base::{self, push_ctxt};
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use trans::common::*;
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use trans::declare;
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use trans::monomorphize;
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use trans::type_::Type;
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use trans::type_of;
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use middle::cast::{CastTy,IntTy};
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use middle::subst::Substs;
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use middle::ty::{self, Ty};
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use util::nodemap::NodeMap;
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use std::iter::repeat;
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use libc::c_uint;
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use syntax::{ast, ast_util};
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use syntax::parse::token;
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use syntax::ptr::P;
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pub type FnArgMap<'a> = Option<&'a NodeMap<ValueRef>>;
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pub fn const_lit(cx: &CrateContext, e: &ast::Expr, lit: &ast::Lit)
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-> ValueRef {
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let _icx = push_ctxt("trans_lit");
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debug!("const_lit: {:?}", lit);
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match lit.node {
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ast::LitByte(b) => C_integral(Type::uint_from_ty(cx, ast::TyU8), b as u64, false),
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ast::LitChar(i) => C_integral(Type::char(cx), i as u64, false),
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ast::LitInt(i, ast::SignedIntLit(t, _)) => {
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C_integral(Type::int_from_ty(cx, t), i, true)
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}
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ast::LitInt(u, ast::UnsignedIntLit(t)) => {
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C_integral(Type::uint_from_ty(cx, t), u, false)
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}
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ast::LitInt(i, ast::UnsuffixedIntLit(_)) => {
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let lit_int_ty = cx.tcx().node_id_to_type(e.id);
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match lit_int_ty.sty {
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ty::TyInt(t) => {
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C_integral(Type::int_from_ty(cx, t), i as u64, true)
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}
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ty::TyUint(t) => {
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C_integral(Type::uint_from_ty(cx, t), i as u64, false)
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}
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_ => cx.sess().span_bug(lit.span,
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&format!("integer literal has type {:?} (expected int \
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or usize)",
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lit_int_ty))
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}
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}
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ast::LitFloat(ref fs, t) => {
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C_floating(&fs, Type::float_from_ty(cx, t))
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}
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ast::LitFloatUnsuffixed(ref fs) => {
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let lit_float_ty = cx.tcx().node_id_to_type(e.id);
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match lit_float_ty.sty {
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ty::TyFloat(t) => {
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C_floating(&fs, Type::float_from_ty(cx, t))
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}
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_ => {
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cx.sess().span_bug(lit.span,
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"floating point literal doesn't have the right type");
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}
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}
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}
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ast::LitBool(b) => C_bool(cx, b),
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ast::LitStr(ref s, _) => C_str_slice(cx, (*s).clone()),
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ast::LitBinary(ref data) => {
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addr_of(cx, C_bytes(cx, &data[..]), "binary")
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}
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}
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}
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pub fn ptrcast(val: ValueRef, ty: Type) -> ValueRef {
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unsafe {
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llvm::LLVMConstPointerCast(val, ty.to_ref())
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}
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}
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fn addr_of_mut(ccx: &CrateContext,
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cv: ValueRef,
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kind: &str)
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-> ValueRef {
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unsafe {
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// FIXME: this totally needs a better name generation scheme, perhaps a simple global
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// counter? Also most other uses of gensym in trans.
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let gsym = token::gensym("_");
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let name = format!("{}{}", kind, gsym.usize());
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let gv = declare::define_global(ccx, &name[..], val_ty(cv)).unwrap_or_else(||{
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ccx.sess().bug(&format!("symbol `{}` is already defined", name));
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});
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llvm::LLVMSetInitializer(gv, cv);
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SetLinkage(gv, InternalLinkage);
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SetUnnamedAddr(gv, true);
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gv
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}
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}
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pub fn addr_of(ccx: &CrateContext,
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cv: ValueRef,
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kind: &str)
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-> ValueRef {
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match ccx.const_globals().borrow().get(&cv) {
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Some(&gv) => return gv,
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None => {}
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}
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let gv = addr_of_mut(ccx, cv, kind);
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unsafe {
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llvm::LLVMSetGlobalConstant(gv, True);
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}
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ccx.const_globals().borrow_mut().insert(cv, gv);
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gv
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}
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fn const_deref_ptr(cx: &CrateContext, v: ValueRef) -> ValueRef {
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let v = match cx.const_unsized().borrow().get(&v) {
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Some(&v) => v,
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None => v
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};
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unsafe {
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llvm::LLVMGetInitializer(v)
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}
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}
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fn const_deref<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
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v: ValueRef,
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ty: Ty<'tcx>)
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-> (ValueRef, Ty<'tcx>) {
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match ty.builtin_deref(true) {
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Some(mt) => {
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if type_is_sized(cx.tcx(), mt.ty) {
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(const_deref_ptr(cx, v), mt.ty)
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} else {
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// Derefing a fat pointer does not change the representation,
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// just the type to the unsized contents.
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(v, mt.ty)
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}
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}
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None => {
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cx.sess().bug(&format!("unexpected dereferenceable type {:?}",
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ty))
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}
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}
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}
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fn const_fn_call<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
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node: ExprOrMethodCall,
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def_id: ast::DefId,
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arg_vals: &[ValueRef],
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param_substs: &'tcx Substs<'tcx>) -> ValueRef {
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let fn_like = const_eval::lookup_const_fn_by_id(ccx.tcx(), def_id);
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let fn_like = fn_like.expect("lookup_const_fn_by_id failed in const_fn_call");
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let args = &fn_like.decl().inputs;
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assert_eq!(args.len(), arg_vals.len());
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let arg_ids = args.iter().map(|arg| arg.pat.id);
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let fn_args = arg_ids.zip(arg_vals.iter().cloned()).collect();
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let substs = ccx.tcx().mk_substs(node_id_substs(ccx, node, param_substs));
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match fn_like.body().expr {
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Some(ref expr) => {
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const_expr(ccx, &**expr, substs, Some(&fn_args)).0
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}
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None => C_nil(ccx)
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}
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}
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pub fn get_const_expr<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
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def_id: ast::DefId,
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ref_expr: &ast::Expr)
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-> &'tcx ast::Expr {
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let def_id = inline::maybe_instantiate_inline(ccx, def_id);
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if def_id.krate != ast::LOCAL_CRATE {
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ccx.sess().span_bug(ref_expr.span,
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"cross crate constant could not be inlined");
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}
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match const_eval::lookup_const_by_id(ccx.tcx(), def_id, Some(ref_expr.id)) {
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Some(ref expr) => expr,
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None => {
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ccx.sess().span_bug(ref_expr.span, "constant item not found")
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}
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}
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}
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fn get_const_val(ccx: &CrateContext,
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def_id: ast::DefId,
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ref_expr: &ast::Expr) -> ValueRef {
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let expr = get_const_expr(ccx, def_id, ref_expr);
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let empty_substs = ccx.tcx().mk_substs(Substs::trans_empty());
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get_const_expr_as_global(ccx, expr, check_const::ConstQualif::empty(), empty_substs)
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}
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pub fn get_const_expr_as_global<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
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expr: &ast::Expr,
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qualif: check_const::ConstQualif,
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param_substs: &'tcx Substs<'tcx>)
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-> ValueRef {
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debug!("get_const_expr_as_global: {:?}", expr.id);
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// Special-case constants to cache a common global for all uses.
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match expr.node {
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ast::ExprPath(..) => {
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let def = ccx.tcx().def_map.borrow().get(&expr.id).unwrap().full_def();
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match def {
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def::DefConst(def_id) | def::DefAssociatedConst(def_id, _) => {
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if !ccx.tcx().tables.borrow().adjustments.contains_key(&expr.id) {
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debug!("get_const_expr_as_global ({:?}): found const {:?}",
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expr.id, def_id);
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return get_const_val(ccx, def_id, expr);
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}
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}
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_ => {}
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}
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}
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_ => {}
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}
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let key = (expr.id, param_substs);
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match ccx.const_values().borrow().get(&key) {
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Some(&val) => return val,
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None => {}
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}
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let val = if qualif.intersects(check_const::ConstQualif::NON_STATIC_BORROWS) {
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// Avoid autorefs as they would create global instead of stack
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// references, even when only the latter are correct.
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let ty = monomorphize::apply_param_substs(ccx.tcx(), param_substs,
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&ccx.tcx().expr_ty(expr));
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const_expr_unadjusted(ccx, expr, ty, param_substs, None)
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} else {
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const_expr(ccx, expr, param_substs, None).0
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};
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// boolean SSA values are i1, but they have to be stored in i8 slots,
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// otherwise some LLVM optimization passes don't work as expected
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let val = unsafe {
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if llvm::LLVMTypeOf(val) == Type::i1(ccx).to_ref() {
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llvm::LLVMConstZExt(val, Type::i8(ccx).to_ref())
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} else {
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val
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}
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};
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let lvalue = addr_of(ccx, val, "const");
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ccx.const_values().borrow_mut().insert(key, lvalue);
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lvalue
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}
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pub fn const_expr<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
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e: &ast::Expr,
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param_substs: &'tcx Substs<'tcx>,
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fn_args: FnArgMap)
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-> (ValueRef, Ty<'tcx>) {
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let ety = monomorphize::apply_param_substs(cx.tcx(), param_substs,
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&cx.tcx().expr_ty(e));
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let llconst = const_expr_unadjusted(cx, e, ety, param_substs, fn_args);
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let mut llconst = llconst;
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let mut ety_adjusted = monomorphize::apply_param_substs(cx.tcx(), param_substs,
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&cx.tcx().expr_ty_adjusted(e));
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let opt_adj = cx.tcx().tables.borrow().adjustments.get(&e.id).cloned();
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match opt_adj {
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Some(ty::AdjustReifyFnPointer) => {
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// FIXME(#19925) once fn item types are
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// zero-sized, we'll need to do something here
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}
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Some(ty::AdjustUnsafeFnPointer) => {
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// purely a type-level thing
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}
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Some(ty::AdjustDerefRef(adj)) => {
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let mut ty = ety;
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// Save the last autoderef in case we can avoid it.
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if adj.autoderefs > 0 {
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for _ in 0..adj.autoderefs-1 {
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let (dv, dt) = const_deref(cx, llconst, ty);
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llconst = dv;
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ty = dt;
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}
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}
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if adj.autoref.is_some() {
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if adj.autoderefs == 0 {
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// Don't copy data to do a deref+ref
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// (i.e., skip the last auto-deref).
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llconst = addr_of(cx, llconst, "autoref");
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ty = cx.tcx().mk_imm_ref(cx.tcx().mk_region(ty::ReStatic), ty);
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}
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} else {
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let (dv, dt) = const_deref(cx, llconst, ty);
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llconst = dv;
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// If we derefed a fat pointer then we will have an
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// open type here. So we need to update the type with
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// the one returned from const_deref.
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ety_adjusted = dt;
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}
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if let Some(target) = adj.unsize {
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let target = monomorphize::apply_param_substs(cx.tcx(),
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param_substs,
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&target);
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let pointee_ty = ty.builtin_deref(true)
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.expect("consts: unsizing got non-pointer type").ty;
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let (base, old_info) = if !type_is_sized(cx.tcx(), pointee_ty) {
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// Normally, the source is a thin pointer and we are
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// adding extra info to make a fat pointer. The exception
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// is when we are upcasting an existing object fat pointer
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// to use a different vtable. In that case, we want to
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// load out the original data pointer so we can repackage
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// it.
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(const_get_elt(cx, llconst, &[abi::FAT_PTR_ADDR as u32]),
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Some(const_get_elt(cx, llconst, &[abi::FAT_PTR_EXTRA as u32])))
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} else {
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(llconst, None)
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};
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let unsized_ty = target.builtin_deref(true)
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.expect("consts: unsizing got non-pointer target type").ty;
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let ptr_ty = type_of::in_memory_type_of(cx, unsized_ty).ptr_to();
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let base = ptrcast(base, ptr_ty);
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let info = expr::unsized_info(cx, pointee_ty, unsized_ty,
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old_info, param_substs);
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if old_info.is_none() {
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let prev_const = cx.const_unsized().borrow_mut()
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.insert(base, llconst);
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assert!(prev_const.is_none() || prev_const == Some(llconst));
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}
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assert_eq!(abi::FAT_PTR_ADDR, 0);
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assert_eq!(abi::FAT_PTR_EXTRA, 1);
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llconst = C_struct(cx, &[base, info], false);
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}
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}
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None => {}
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};
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let llty = type_of::sizing_type_of(cx, ety_adjusted);
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let csize = machine::llsize_of_alloc(cx, val_ty(llconst));
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let tsize = machine::llsize_of_alloc(cx, llty);
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if csize != tsize {
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cx.sess().abort_if_errors();
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unsafe {
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// FIXME these values could use some context
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llvm::LLVMDumpValue(llconst);
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llvm::LLVMDumpValue(C_undef(llty));
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}
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cx.sess().bug(&format!("const {:?} of type {:?} has size {} instead of {}",
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e, ety_adjusted,
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csize, tsize));
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}
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(llconst, ety_adjusted)
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}
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fn check_unary_expr_validity(cx: &CrateContext, e: &ast::Expr, t: Ty,
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te: ValueRef) {
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// The only kind of unary expression that we check for validity
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// here is `-expr`, to check if it "overflows" (e.g. `-i32::MIN`).
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if let ast::ExprUnary(ast::UnNeg, ref inner_e) = e.node {
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// An unfortunate special case: we parse e.g. -128 as a
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// negation of the literal 128, which means if we're expecting
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// a i8 (or if it was already suffixed, e.g. `-128_i8`), then
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// 128 will have already overflowed to -128, and so then the
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// constant evaluator thinks we're trying to negate -128.
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//
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// Catch this up front by looking for ExprLit directly,
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// and just accepting it.
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if let ast::ExprLit(_) = inner_e.node { return; }
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let result = match t.sty {
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ty::TyInt(int_type) => {
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let input = match const_to_opt_int(te) {
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Some(v) => v,
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None => return,
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};
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const_int_checked_neg(
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input, e, Some(const_eval::IntTy::from(cx.tcx(), int_type)))
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}
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ty::TyUint(uint_type) => {
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let input = match const_to_opt_uint(te) {
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Some(v) => v,
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None => return,
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};
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const_uint_checked_neg(
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input, e, Some(const_eval::UintTy::from(cx.tcx(), uint_type)))
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}
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_ => return,
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};
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// We do not actually care about a successful result.
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if let Err(err) = result {
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cx.tcx().sess.span_err(e.span, &err.description());
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}
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}
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}
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fn check_binary_expr_validity(cx: &CrateContext, e: &ast::Expr, t: Ty,
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te1: ValueRef, te2: ValueRef) {
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let b = if let ast::ExprBinary(b, _, _) = e.node { b } else { return };
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let result = match t.sty {
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ty::TyInt(int_type) => {
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let (lhs, rhs) = match (const_to_opt_int(te1),
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const_to_opt_int(te2)) {
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(Some(v1), Some(v2)) => (v1, v2),
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_ => return,
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};
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let opt_ety = Some(const_eval::IntTy::from(cx.tcx(), int_type));
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match b.node {
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ast::BiAdd => const_int_checked_add(lhs, rhs, e, opt_ety),
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ast::BiSub => const_int_checked_sub(lhs, rhs, e, opt_ety),
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ast::BiMul => const_int_checked_mul(lhs, rhs, e, opt_ety),
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ast::BiDiv => const_int_checked_div(lhs, rhs, e, opt_ety),
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ast::BiRem => const_int_checked_rem(lhs, rhs, e, opt_ety),
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ast::BiShl => const_int_checked_shl(lhs, rhs, e, opt_ety),
|
|
ast::BiShr => const_int_checked_shr(lhs, rhs, e, opt_ety),
|
|
_ => return,
|
|
}
|
|
}
|
|
ty::TyUint(uint_type) => {
|
|
let (lhs, rhs) = match (const_to_opt_uint(te1),
|
|
const_to_opt_uint(te2)) {
|
|
(Some(v1), Some(v2)) => (v1, v2),
|
|
_ => return,
|
|
};
|
|
|
|
let opt_ety = Some(const_eval::UintTy::from(cx.tcx(), uint_type));
|
|
match b.node {
|
|
ast::BiAdd => const_uint_checked_add(lhs, rhs, e, opt_ety),
|
|
ast::BiSub => const_uint_checked_sub(lhs, rhs, e, opt_ety),
|
|
ast::BiMul => const_uint_checked_mul(lhs, rhs, e, opt_ety),
|
|
ast::BiDiv => const_uint_checked_div(lhs, rhs, e, opt_ety),
|
|
ast::BiRem => const_uint_checked_rem(lhs, rhs, e, opt_ety),
|
|
ast::BiShl => const_uint_checked_shl(lhs, rhs, e, opt_ety),
|
|
ast::BiShr => const_uint_checked_shr(lhs, rhs, e, opt_ety),
|
|
_ => return,
|
|
}
|
|
}
|
|
_ => return,
|
|
};
|
|
// We do not actually care about a successful result.
|
|
if let Err(err) = result {
|
|
cx.tcx().sess.span_err(e.span, &err.description());
|
|
}
|
|
}
|
|
|
|
fn const_expr_unadjusted<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
|
|
e: &ast::Expr,
|
|
ety: Ty<'tcx>,
|
|
param_substs: &'tcx Substs<'tcx>,
|
|
fn_args: FnArgMap)
|
|
-> ValueRef
|
|
{
|
|
debug!("const_expr_unadjusted(e={:?}, ety={:?}, param_substs={:?})",
|
|
e,
|
|
ety,
|
|
param_substs);
|
|
|
|
let map_list = |exprs: &[P<ast::Expr>]| -> Vec<ValueRef> {
|
|
exprs.iter()
|
|
.map(|e| const_expr(cx, &**e, param_substs, fn_args).0)
|
|
.collect()
|
|
};
|
|
let _icx = push_ctxt("const_expr");
|
|
match e.node {
|
|
ast::ExprLit(ref lit) => {
|
|
const_lit(cx, e, &**lit)
|
|
},
|
|
ast::ExprBinary(b, ref e1, ref e2) => {
|
|
/* Neither type is bottom, and we expect them to be unified
|
|
* already, so the following is safe. */
|
|
let (te1, ty) = const_expr(cx, &**e1, param_substs, fn_args);
|
|
debug!("const_expr_unadjusted: te1={}, ty={:?}",
|
|
cx.tn().val_to_string(te1),
|
|
ty);
|
|
let is_simd = ty.is_simd(cx.tcx());
|
|
let intype = if is_simd {
|
|
ty.simd_type(cx.tcx())
|
|
} else {
|
|
ty
|
|
};
|
|
let is_float = intype.is_fp();
|
|
let signed = intype.is_signed();
|
|
|
|
let (te2, _) = const_expr(cx, &**e2, param_substs, fn_args);
|
|
|
|
check_binary_expr_validity(cx, e, ty, te1, te2);
|
|
|
|
unsafe { match b.node {
|
|
ast::BiAdd if is_float => llvm::LLVMConstFAdd(te1, te2),
|
|
ast::BiAdd => llvm::LLVMConstAdd(te1, te2),
|
|
|
|
ast::BiSub if is_float => llvm::LLVMConstFSub(te1, te2),
|
|
ast::BiSub => llvm::LLVMConstSub(te1, te2),
|
|
|
|
ast::BiMul if is_float => llvm::LLVMConstFMul(te1, te2),
|
|
ast::BiMul => llvm::LLVMConstMul(te1, te2),
|
|
|
|
ast::BiDiv if is_float => llvm::LLVMConstFDiv(te1, te2),
|
|
ast::BiDiv if signed => llvm::LLVMConstSDiv(te1, te2),
|
|
ast::BiDiv => llvm::LLVMConstUDiv(te1, te2),
|
|
|
|
ast::BiRem if is_float => llvm::LLVMConstFRem(te1, te2),
|
|
ast::BiRem if signed => llvm::LLVMConstSRem(te1, te2),
|
|
ast::BiRem => llvm::LLVMConstURem(te1, te2),
|
|
|
|
ast::BiAnd => llvm::LLVMConstAnd(te1, te2),
|
|
ast::BiOr => llvm::LLVMConstOr(te1, te2),
|
|
ast::BiBitXor => llvm::LLVMConstXor(te1, te2),
|
|
ast::BiBitAnd => llvm::LLVMConstAnd(te1, te2),
|
|
ast::BiBitOr => llvm::LLVMConstOr(te1, te2),
|
|
ast::BiShl => {
|
|
let te2 = base::cast_shift_const_rhs(b.node, te1, te2);
|
|
llvm::LLVMConstShl(te1, te2)
|
|
},
|
|
ast::BiShr => {
|
|
let te2 = base::cast_shift_const_rhs(b.node, te1, te2);
|
|
if signed { llvm::LLVMConstAShr(te1, te2) }
|
|
else { llvm::LLVMConstLShr(te1, te2) }
|
|
},
|
|
ast::BiEq | ast::BiNe | ast::BiLt | ast::BiLe | ast::BiGt | ast::BiGe => {
|
|
if is_float {
|
|
let cmp = base::bin_op_to_fcmp_predicate(cx, b.node);
|
|
ConstFCmp(cmp, te1, te2)
|
|
} else {
|
|
let cmp = base::bin_op_to_icmp_predicate(cx, b.node, signed);
|
|
let bool_val = ConstICmp(cmp, te1, te2);
|
|
if is_simd {
|
|
// LLVM outputs an `< size x i1 >`, so we need to perform
|
|
// a sign extension to get the correctly sized type.
|
|
llvm::LLVMConstIntCast(bool_val, val_ty(te1).to_ref(), True)
|
|
} else {
|
|
bool_val
|
|
}
|
|
}
|
|
},
|
|
} } // unsafe { match b.node {
|
|
},
|
|
ast::ExprUnary(u, ref inner_e) => {
|
|
let (te, ty) = const_expr(cx, &**inner_e, param_substs, fn_args);
|
|
|
|
check_unary_expr_validity(cx, e, ty, te);
|
|
|
|
let is_float = ty.is_fp();
|
|
unsafe { match u {
|
|
ast::UnUniq | ast::UnDeref => const_deref(cx, te, ty).0,
|
|
ast::UnNot => llvm::LLVMConstNot(te),
|
|
ast::UnNeg if is_float => llvm::LLVMConstFNeg(te),
|
|
ast::UnNeg => llvm::LLVMConstNeg(te),
|
|
} }
|
|
},
|
|
ast::ExprField(ref base, field) => {
|
|
let (bv, bt) = const_expr(cx, &**base, param_substs, fn_args);
|
|
let brepr = adt::represent_type(cx, bt);
|
|
expr::with_field_tys(cx.tcx(), bt, None, |discr, field_tys| {
|
|
let ix = cx.tcx().field_idx_strict(field.node.name, field_tys);
|
|
adt::const_get_field(cx, &*brepr, bv, discr, ix)
|
|
})
|
|
},
|
|
ast::ExprTupField(ref base, idx) => {
|
|
let (bv, bt) = const_expr(cx, &**base, param_substs, fn_args);
|
|
let brepr = adt::represent_type(cx, bt);
|
|
expr::with_field_tys(cx.tcx(), bt, None, |discr, _| {
|
|
adt::const_get_field(cx, &*brepr, bv, discr, idx.node)
|
|
})
|
|
},
|
|
|
|
ast::ExprIndex(ref base, ref index) => {
|
|
let (bv, bt) = const_expr(cx, &**base, param_substs, fn_args);
|
|
let iv = match const_eval::eval_const_expr_partial(cx.tcx(), &**index, None) {
|
|
Ok(ConstVal::Int(i)) => i as u64,
|
|
Ok(ConstVal::Uint(u)) => u,
|
|
_ => cx.sess().span_bug(index.span,
|
|
"index is not an integer-constant expression")
|
|
};
|
|
let (arr, len) = match bt.sty {
|
|
ty::TyArray(_, u) => (bv, C_uint(cx, u)),
|
|
ty::TySlice(_) | ty::TyStr => {
|
|
let e1 = const_get_elt(cx, bv, &[0]);
|
|
(const_deref_ptr(cx, e1), const_get_elt(cx, bv, &[1]))
|
|
},
|
|
ty::TyRef(_, mt) => match mt.ty.sty {
|
|
ty::TyArray(_, u) => {
|
|
(const_deref_ptr(cx, bv), C_uint(cx, u))
|
|
},
|
|
_ => cx.sess().span_bug(base.span,
|
|
&format!("index-expr base must be a vector \
|
|
or string type, found {:?}",
|
|
bt)),
|
|
},
|
|
_ => cx.sess().span_bug(base.span,
|
|
&format!("index-expr base must be a vector \
|
|
or string type, found {:?}",
|
|
bt)),
|
|
};
|
|
|
|
let len = unsafe { llvm::LLVMConstIntGetZExtValue(len) as u64 };
|
|
let len = match bt.sty {
|
|
ty::TyBox(ty) | ty::TyRef(_, ty::TypeAndMut{ty, ..}) => match ty.sty {
|
|
ty::TyStr => {
|
|
assert!(len > 0);
|
|
len - 1
|
|
},
|
|
_ => len,
|
|
},
|
|
_ => len,
|
|
};
|
|
if iv >= len {
|
|
// FIXME #3170: report this earlier on in the const-eval
|
|
// pass. Reporting here is a bit late.
|
|
cx.sess().span_err(e.span,
|
|
"const index-expr is out of bounds");
|
|
C_undef(type_of::type_of(cx, bt).element_type())
|
|
} else {
|
|
const_get_elt(cx, arr, &[iv as c_uint])
|
|
}
|
|
},
|
|
ast::ExprCast(ref base, _) => {
|
|
let t_cast = ety;
|
|
let llty = type_of::type_of(cx, t_cast);
|
|
let (v, t_expr) = const_expr(cx, &**base, param_substs, fn_args);
|
|
debug!("trans_const_cast({:?} as {:?})", t_expr, t_cast);
|
|
if expr::cast_is_noop(cx.tcx(), base, t_expr, t_cast) {
|
|
return v;
|
|
}
|
|
if type_is_fat_ptr(cx.tcx(), t_expr) {
|
|
// Fat pointer casts.
|
|
let t_cast_inner = t_cast.builtin_deref(true).expect("cast to non-pointer").ty;
|
|
let ptr_ty = type_of::in_memory_type_of(cx, t_cast_inner).ptr_to();
|
|
let addr = ptrcast(const_get_elt(cx, v, &[abi::FAT_PTR_ADDR as u32]),
|
|
ptr_ty);
|
|
if type_is_fat_ptr(cx.tcx(), t_cast) {
|
|
let info = const_get_elt(cx, v, &[abi::FAT_PTR_EXTRA as u32]);
|
|
return C_struct(cx, &[addr, info], false)
|
|
} else {
|
|
return addr;
|
|
}
|
|
}
|
|
unsafe { match (
|
|
CastTy::from_ty(cx.tcx(), t_expr).expect("bad input type for cast"),
|
|
CastTy::from_ty(cx.tcx(), t_cast).expect("bad output type for cast"),
|
|
) {
|
|
(CastTy::Int(IntTy::CEnum), CastTy::Int(_)) => {
|
|
let repr = adt::represent_type(cx, t_expr);
|
|
let discr = adt::const_get_discrim(cx, &*repr, v);
|
|
let iv = C_integral(cx.int_type(), discr, false);
|
|
let s = adt::is_discr_signed(&*repr) as Bool;
|
|
llvm::LLVMConstIntCast(iv, llty.to_ref(), s)
|
|
},
|
|
(CastTy::Int(_), CastTy::Int(_)) => {
|
|
let s = t_expr.is_signed() as Bool;
|
|
llvm::LLVMConstIntCast(v, llty.to_ref(), s)
|
|
},
|
|
(CastTy::Int(_), CastTy::Float) => {
|
|
if t_expr.is_signed() {
|
|
llvm::LLVMConstSIToFP(v, llty.to_ref())
|
|
} else {
|
|
llvm::LLVMConstUIToFP(v, llty.to_ref())
|
|
}
|
|
},
|
|
(CastTy::Float, CastTy::Float) => llvm::LLVMConstFPCast(v, llty.to_ref()),
|
|
(CastTy::Float, CastTy::Int(IntTy::I)) => llvm::LLVMConstFPToSI(v, llty.to_ref()),
|
|
(CastTy::Float, CastTy::Int(_)) => llvm::LLVMConstFPToUI(v, llty.to_ref()),
|
|
(CastTy::Ptr(_), CastTy::Ptr(_)) | (CastTy::FnPtr, CastTy::Ptr(_))
|
|
| (CastTy::RPtr(_), CastTy::Ptr(_)) => {
|
|
ptrcast(v, llty)
|
|
},
|
|
(CastTy::FnPtr, CastTy::FnPtr) => ptrcast(v, llty), // isn't this a coercion?
|
|
(CastTy::Int(_), CastTy::Ptr(_)) => llvm::LLVMConstIntToPtr(v, llty.to_ref()),
|
|
(CastTy::Ptr(_), CastTy::Int(_)) | (CastTy::FnPtr, CastTy::Int(_)) => {
|
|
llvm::LLVMConstPtrToInt(v, llty.to_ref())
|
|
},
|
|
_ => {
|
|
cx.sess().impossible_case(e.span,
|
|
"bad combination of types for cast")
|
|
},
|
|
} } // unsafe { match ( ... ) {
|
|
},
|
|
ast::ExprAddrOf(ast::MutImmutable, ref sub) => {
|
|
// If this is the address of some static, then we need to return
|
|
// the actual address of the static itself (short circuit the rest
|
|
// of const eval).
|
|
let mut cur = sub;
|
|
loop {
|
|
match cur.node {
|
|
ast::ExprParen(ref sub) => cur = sub,
|
|
ast::ExprBlock(ref blk) => {
|
|
if let Some(ref sub) = blk.expr {
|
|
cur = sub;
|
|
} else {
|
|
break;
|
|
}
|
|
},
|
|
_ => break,
|
|
}
|
|
}
|
|
let opt_def = cx.tcx().def_map.borrow().get(&cur.id).map(|d| d.full_def());
|
|
if let Some(def::DefStatic(def_id, _)) = opt_def {
|
|
get_static_val(cx, def_id, ety)
|
|
} else {
|
|
// If this isn't the address of a static, then keep going through
|
|
// normal constant evaluation.
|
|
let (v, _) = const_expr(cx, &**sub, param_substs, fn_args);
|
|
addr_of(cx, v, "ref")
|
|
}
|
|
},
|
|
ast::ExprAddrOf(ast::MutMutable, ref sub) => {
|
|
let (v, _) = const_expr(cx, &**sub, param_substs, fn_args);
|
|
addr_of_mut(cx, v, "ref_mut_slice")
|
|
},
|
|
ast::ExprTup(ref es) => {
|
|
let repr = adt::represent_type(cx, ety);
|
|
let vals = map_list(&es[..]);
|
|
adt::trans_const(cx, &*repr, 0, &vals[..])
|
|
},
|
|
ast::ExprStruct(_, ref fs, ref base_opt) => {
|
|
let repr = adt::represent_type(cx, ety);
|
|
|
|
let base_val = match *base_opt {
|
|
Some(ref base) => Some(const_expr(cx, &**base, param_substs, fn_args)),
|
|
None => None
|
|
};
|
|
|
|
expr::with_field_tys(cx.tcx(), ety, Some(e.id), |discr, field_tys| {
|
|
let cs = field_tys.iter().enumerate()
|
|
.map(|(ix, &field_ty)| {
|
|
match (fs.iter().find(|f| field_ty.name == f.ident.node.name), base_val) {
|
|
(Some(ref f), _) => const_expr(cx, &*f.expr, param_substs, fn_args).0,
|
|
(_, Some((bv, _))) => adt::const_get_field(cx, &*repr, bv, discr, ix),
|
|
(_, None) => cx.sess().span_bug(e.span, "missing struct field"),
|
|
}
|
|
}).collect::<Vec<_>>();
|
|
if ety.is_simd(cx.tcx()) {
|
|
C_vector(&cs[..])
|
|
} else {
|
|
adt::trans_const(cx, &*repr, discr, &cs[..])
|
|
}
|
|
})
|
|
},
|
|
ast::ExprVec(ref es) => {
|
|
let unit_ty = ety.sequence_element_type(cx.tcx());
|
|
let llunitty = type_of::type_of(cx, unit_ty);
|
|
let vs = es.iter()
|
|
.map(|e| const_expr(cx, &**e, param_substs, fn_args).0)
|
|
.collect::<Vec<_>>();
|
|
// If the vector contains enums, an LLVM array won't work.
|
|
if vs.iter().any(|vi| val_ty(*vi) != llunitty) {
|
|
C_struct(cx, &vs[..], false)
|
|
} else {
|
|
C_array(llunitty, &vs[..])
|
|
}
|
|
},
|
|
ast::ExprRepeat(ref elem, ref count) => {
|
|
let unit_ty = ety.sequence_element_type(cx.tcx());
|
|
let llunitty = type_of::type_of(cx, unit_ty);
|
|
let n = cx.tcx().eval_repeat_count(count);
|
|
let unit_val = const_expr(cx, &**elem, param_substs, fn_args).0;
|
|
let vs: Vec<_> = repeat(unit_val).take(n).collect();
|
|
if val_ty(unit_val) != llunitty {
|
|
C_struct(cx, &vs[..], false)
|
|
} else {
|
|
C_array(llunitty, &vs[..])
|
|
}
|
|
},
|
|
ast::ExprPath(..) => {
|
|
let def = cx.tcx().def_map.borrow().get(&e.id).unwrap().full_def();
|
|
match def {
|
|
def::DefLocal(id) => {
|
|
if let Some(val) = fn_args.and_then(|args| args.get(&id).cloned()) {
|
|
val
|
|
} else {
|
|
cx.sess().span_bug(e.span, "const fn argument not found")
|
|
}
|
|
}
|
|
def::DefFn(..) | def::DefMethod(..) => {
|
|
expr::trans_def_fn_unadjusted(cx, e, def, param_substs).val
|
|
}
|
|
def::DefConst(def_id) | def::DefAssociatedConst(def_id, _) => {
|
|
const_deref_ptr(cx, get_const_val(cx, def_id, e))
|
|
}
|
|
def::DefVariant(enum_did, variant_did, _) => {
|
|
let vinfo = cx.tcx().enum_variant_with_id(enum_did, variant_did);
|
|
if !vinfo.args.is_empty() {
|
|
// N-ary variant.
|
|
expr::trans_def_fn_unadjusted(cx, e, def, param_substs).val
|
|
} else {
|
|
// Nullary variant.
|
|
let repr = adt::represent_type(cx, ety);
|
|
adt::trans_const(cx, &*repr, vinfo.disr_val, &[])
|
|
}
|
|
}
|
|
def::DefStruct(_) => {
|
|
if let ty::TyBareFn(..) = ety.sty {
|
|
// Tuple struct.
|
|
expr::trans_def_fn_unadjusted(cx, e, def, param_substs).val
|
|
} else {
|
|
// Unit struct.
|
|
C_null(type_of::type_of(cx, ety))
|
|
}
|
|
}
|
|
_ => {
|
|
cx.sess().span_bug(e.span, "expected a const, fn, struct, \
|
|
or variant def")
|
|
}
|
|
}
|
|
},
|
|
ast::ExprCall(ref callee, ref args) => {
|
|
let mut callee = &**callee;
|
|
loop {
|
|
callee = match callee.node {
|
|
ast::ExprParen(ref inner) => &**inner,
|
|
ast::ExprBlock(ref block) => match block.expr {
|
|
Some(ref tail) => &**tail,
|
|
None => break,
|
|
},
|
|
_ => break,
|
|
};
|
|
}
|
|
let def = cx.tcx().def_map.borrow()[&callee.id].full_def();
|
|
let arg_vals = map_list(args);
|
|
match def {
|
|
def::DefFn(did, _) | def::DefMethod(did, _) => {
|
|
const_fn_call(cx, ExprId(callee.id), did, &arg_vals, param_substs)
|
|
},
|
|
def::DefStruct(_) => {
|
|
if ety.is_simd(cx.tcx()) {
|
|
C_vector(&arg_vals[..])
|
|
} else {
|
|
let repr = adt::represent_type(cx, ety);
|
|
adt::trans_const(cx, &*repr, 0, &arg_vals[..])
|
|
}
|
|
},
|
|
def::DefVariant(enum_did, variant_did, _) => {
|
|
let repr = adt::represent_type(cx, ety);
|
|
let vinfo = cx.tcx().enum_variant_with_id(enum_did, variant_did);
|
|
adt::trans_const(cx,
|
|
&*repr,
|
|
vinfo.disr_val,
|
|
&arg_vals[..])
|
|
},
|
|
_ => cx.sess().span_bug(e.span, "expected a struct, variant, or const fn def"),
|
|
}
|
|
},
|
|
ast::ExprMethodCall(_, _, ref args) => {
|
|
let arg_vals = map_list(args);
|
|
let method_call = ty::MethodCall::expr(e.id);
|
|
let method_did = cx.tcx().tables.borrow().method_map[&method_call].def_id;
|
|
const_fn_call(cx, MethodCallKey(method_call),
|
|
method_did, &arg_vals, param_substs)
|
|
},
|
|
ast::ExprParen(ref e) => const_expr(cx, &**e, param_substs, fn_args).0,
|
|
ast::ExprBlock(ref block) => {
|
|
match block.expr {
|
|
Some(ref expr) => const_expr(cx, &**expr, param_substs, fn_args).0,
|
|
None => C_nil(cx),
|
|
}
|
|
},
|
|
ast::ExprClosure(_, ref decl, ref body) => {
|
|
closure::trans_closure_expr(closure::Dest::Ignore(cx),
|
|
decl,
|
|
body,
|
|
e.id,
|
|
param_substs);
|
|
C_null(type_of::type_of(cx, ety))
|
|
},
|
|
_ => cx.sess().span_bug(e.span,
|
|
"bad constant expression type in consts::const_expr"),
|
|
}
|
|
}
|
|
|
|
pub fn trans_static(ccx: &CrateContext, m: ast::Mutability, id: ast::NodeId) -> ValueRef {
|
|
unsafe {
|
|
let _icx = push_ctxt("trans_static");
|
|
let g = base::get_item_val(ccx, id);
|
|
// At this point, get_item_val has already translated the
|
|
// constant's initializer to determine its LLVM type.
|
|
let v = ccx.static_values().borrow().get(&id).unwrap().clone();
|
|
// boolean SSA values are i1, but they have to be stored in i8 slots,
|
|
// otherwise some LLVM optimization passes don't work as expected
|
|
let v = if llvm::LLVMTypeOf(v) == Type::i1(ccx).to_ref() {
|
|
llvm::LLVMConstZExt(v, Type::i8(ccx).to_ref())
|
|
} else {
|
|
v
|
|
};
|
|
llvm::LLVMSetInitializer(g, v);
|
|
|
|
// As an optimization, all shared statics which do not have interior
|
|
// mutability are placed into read-only memory.
|
|
if m != ast::MutMutable {
|
|
let node_ty = ccx.tcx().node_id_to_type(id);
|
|
let tcontents = node_ty.type_contents(ccx.tcx());
|
|
if !tcontents.interior_unsafe() {
|
|
llvm::LLVMSetGlobalConstant(g, True);
|
|
}
|
|
}
|
|
debuginfo::create_global_var_metadata(ccx, id, g);
|
|
g
|
|
}
|
|
}
|
|
|
|
fn get_static_val<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, did: ast::DefId,
|
|
ty: Ty<'tcx>) -> ValueRef {
|
|
if ast_util::is_local(did) { return base::get_item_val(ccx, did.node) }
|
|
base::trans_external_path(ccx, did, ty)
|
|
}
|