rust/src/librustc/middle/trans/consts.rs
Nick Cameron ce0907e46e Add enum variants to the type namespace
Change to resolve and update compiler and libs for uses.

[breaking-change]

Enum variants are now in both the value and type namespaces. This means that
if you have a variant with the same name as a type in scope in a module, you
will get a name clash and thus an error. The solution is to either rename the
type or the variant.
2014-09-19 15:11:00 +12:00

717 lines
32 KiB
Rust

// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use back::abi;
use llvm;
use llvm::{ConstFCmp, ConstICmp, SetLinkage, PrivateLinkage, ValueRef, Bool, True, False};
use llvm::{IntEQ, IntNE, IntUGT, IntUGE, IntULT, IntULE, IntSGT, IntSGE, IntSLT, IntSLE,
RealOEQ, RealOGT, RealOGE, RealOLT, RealOLE, RealONE};
use metadata::csearch;
use middle::const_eval;
use middle::def;
use middle::trans::adt;
use middle::trans::base;
use middle::trans::base::push_ctxt;
use middle::trans::closure;
use middle::trans::common::*;
use middle::trans::consts;
use middle::trans::expr;
use middle::trans::inline;
use middle::trans::machine;
use middle::trans::type_::Type;
use middle::trans::type_of;
use middle::trans::debuginfo;
use middle::ty;
use util::ppaux::{Repr, ty_to_string};
use std::c_str::ToCStr;
use std::vec;
use libc::c_uint;
use syntax::{ast, ast_util};
use syntax::ptr::P;
pub fn const_lit(cx: &CrateContext, e: &ast::Expr, lit: &ast::Lit)
-> ValueRef {
let _icx = push_ctxt("trans_lit");
debug!("const_lit: {}", lit);
match lit.node {
ast::LitByte(b) => C_integral(Type::uint_from_ty(cx, ast::TyU8), b as u64, false),
ast::LitChar(i) => C_integral(Type::char(cx), i as u64, false),
ast::LitInt(i, ast::SignedIntLit(t, _)) => {
C_integral(Type::int_from_ty(cx, t), i, true)
}
ast::LitInt(u, ast::UnsignedIntLit(t)) => {
C_integral(Type::uint_from_ty(cx, t), u, false)
}
ast::LitInt(i, ast::UnsuffixedIntLit(_)) => {
let lit_int_ty = ty::node_id_to_type(cx.tcx(), e.id);
match ty::get(lit_int_ty).sty {
ty::ty_int(t) => {
C_integral(Type::int_from_ty(cx, t), i as u64, true)
}
ty::ty_uint(t) => {
C_integral(Type::uint_from_ty(cx, t), i as u64, false)
}
_ => cx.sess().span_bug(lit.span,
format!("integer literal has type {} (expected int \
or uint)",
ty_to_string(cx.tcx(), lit_int_ty)).as_slice())
}
}
ast::LitFloat(ref fs, t) => {
C_floating(fs.get(), Type::float_from_ty(cx, t))
}
ast::LitFloatUnsuffixed(ref fs) => {
let lit_float_ty = ty::node_id_to_type(cx.tcx(), e.id);
match ty::get(lit_float_ty).sty {
ty::ty_float(t) => {
C_floating(fs.get(), Type::float_from_ty(cx, t))
}
_ => {
cx.sess().span_bug(lit.span,
"floating point literal doesn't have the right type");
}
}
}
ast::LitBool(b) => C_bool(cx, b),
ast::LitNil => C_nil(cx),
ast::LitStr(ref s, _) => C_str_slice(cx, (*s).clone()),
ast::LitBinary(ref data) => C_binary_slice(cx, data.as_slice()),
}
}
pub fn const_ptrcast(cx: &CrateContext, a: ValueRef, t: Type) -> ValueRef {
unsafe {
let b = llvm::LLVMConstPointerCast(a, t.ptr_to().to_ref());
assert!(cx.const_globals().borrow_mut().insert(b as int, a));
b
}
}
// Helper function because we don't have tuple-swizzling.
fn first_two<R, S, T>((a, b, _): (R, S, T)) -> (R, S) {
(a, b)
}
fn const_vec(cx: &CrateContext, e: &ast::Expr,
es: &[P<ast::Expr>], is_local: bool) -> (ValueRef, Type, bool) {
let vec_ty = ty::expr_ty(cx.tcx(), e);
let unit_ty = ty::sequence_element_type(cx.tcx(), vec_ty);
let llunitty = type_of::type_of(cx, unit_ty);
let (vs, inlineable) = vec::unzip(es.iter().map(|e| first_two(const_expr(cx, &**e, is_local))));
// If the vector contains enums, an LLVM array won't work.
let v = if vs.iter().any(|vi| val_ty(*vi) != llunitty) {
C_struct(cx, vs.as_slice(), false)
} else {
C_array(llunitty, vs.as_slice())
};
(v, llunitty, inlineable.iter().fold(true, |a, &b| a && b))
}
pub fn const_addr_of(cx: &CrateContext, cv: ValueRef, mutbl: ast::Mutability) -> ValueRef {
unsafe {
let gv = "const".with_c_str(|name| {
llvm::LLVMAddGlobal(cx.llmod(), val_ty(cv).to_ref(), name)
});
llvm::LLVMSetInitializer(gv, cv);
llvm::LLVMSetGlobalConstant(gv,
if mutbl == ast::MutImmutable {True} else {False});
SetLinkage(gv, PrivateLinkage);
gv
}
}
fn const_deref_ptr(cx: &CrateContext, v: ValueRef) -> ValueRef {
let v = match cx.const_globals().borrow().find(&(v as int)) {
Some(&v) => v,
None => v
};
unsafe {
llvm::LLVMGetInitializer(v)
}
}
fn const_deref_newtype(cx: &CrateContext, v: ValueRef, t: ty::t)
-> ValueRef {
let repr = adt::represent_type(cx, t);
adt::const_get_field(cx, &*repr, v, 0, 0)
}
fn const_deref(cx: &CrateContext, v: ValueRef, t: ty::t, explicit: bool)
-> (ValueRef, ty::t) {
match ty::deref(t, explicit) {
Some(ref mt) => {
match ty::get(t).sty {
ty::ty_ptr(mt) | ty::ty_rptr(_, mt) => {
if ty::type_is_sized(cx.tcx(), mt.ty) {
(const_deref_ptr(cx, v), mt.ty)
} else {
// Derefing a fat pointer does not change the representation,
// just the type to ty_open.
(v, ty::mk_open(cx.tcx(), mt.ty))
}
}
ty::ty_enum(..) | ty::ty_struct(..) => {
assert!(mt.mutbl != ast::MutMutable);
(const_deref_newtype(cx, v, t), mt.ty)
}
_ => {
cx.sess().bug(format!("unexpected dereferenceable type {}",
ty_to_string(cx.tcx(), t)).as_slice())
}
}
}
None => {
cx.sess().bug(format!("cannot dereference const of type {}",
ty_to_string(cx.tcx(), t)).as_slice())
}
}
}
pub fn get_const_val(cx: &CrateContext,
mut def_id: ast::DefId) -> (ValueRef, bool) {
let contains_key = cx.const_values().borrow().contains_key(&def_id.node);
if !ast_util::is_local(def_id) || !contains_key {
if !ast_util::is_local(def_id) {
def_id = inline::maybe_instantiate_inline(cx, def_id);
}
match cx.tcx().map.expect_item(def_id.node).node {
ast::ItemStatic(_, ast::MutImmutable, _) => {
trans_const(cx, ast::MutImmutable, def_id.node);
}
_ => {}
}
}
(cx.const_values().borrow().get_copy(&def_id.node),
!cx.non_inlineable_statics().borrow().contains(&def_id.node))
}
pub fn const_expr(cx: &CrateContext, e: &ast::Expr, is_local: bool) -> (ValueRef, bool, ty::t) {
let (llconst, inlineable) = const_expr_unadjusted(cx, e, is_local);
let mut llconst = llconst;
let mut inlineable = inlineable;
let ety = ty::expr_ty(cx.tcx(), e);
let mut ety_adjusted = ty::expr_ty_adjusted(cx.tcx(), e);
let opt_adj = cx.tcx().adjustments.borrow().find_copy(&e.id);
match opt_adj {
None => { }
Some(adj) => {
match adj {
ty::AdjustAddEnv(ty::RegionTraitStore(ty::ReStatic, _)) => {
let def = ty::resolve_expr(cx.tcx(), e);
let wrapper = closure::get_wrapper_for_bare_fn(cx,
ety_adjusted,
def,
llconst,
is_local);
llconst = C_struct(cx, [wrapper, C_null(Type::i8p(cx))], false)
}
ty::AdjustAddEnv(store) => {
cx.sess()
.span_bug(e.span,
format!("unexpected static function: {:?}",
store).as_slice())
}
ty::AdjustDerefRef(ref adj) => {
let mut ty = ety;
// Save the last autoderef in case we can avoid it.
if adj.autoderefs > 0 {
for _ in range(0, adj.autoderefs-1) {
let (dv, dt) = const_deref(cx, llconst, ty, false);
llconst = dv;
ty = dt;
}
}
match adj.autoref {
None => {
let (dv, dt) = const_deref(cx, llconst, ty, false);
llconst = dv;
// If we derefed a fat pointer then we will have an
// open type here. So we need to update the type with
// the one returned from const_deref.
ety_adjusted = dt;
}
Some(ref autoref) => {
match *autoref {
ty::AutoUnsafe(_, None) |
ty::AutoPtr(ty::ReStatic, _, None) => {
// Don't copy data to do a deref+ref
// (i.e., skip the last auto-deref).
if adj.autoderefs == 0 {
inlineable = false;
llconst = const_addr_of(cx, llconst, ast::MutImmutable);
}
}
ty::AutoPtr(ty::ReStatic, _, Some(box ty::AutoUnsize(..))) => {
if adj.autoderefs > 0 {
// Seeing as we are deref'ing here and take a reference
// again to make the pointer part of the far pointer below,
// we just skip the whole thing. We still need the type
// though. This works even if we don't need to deref
// because of byref semantics. Note that this is not just
// an optimisation, it is necessary for mutable vectors to
// work properly.
let (_, dt) = const_deref(cx, llconst, ty, false);
ty = dt;
} else {
llconst = const_addr_of(cx, llconst, ast::MutImmutable)
}
match ty::get(ty).sty {
ty::ty_vec(unit_ty, Some(len)) => {
inlineable = false;
let llunitty = type_of::type_of(cx, unit_ty);
let llptr = const_ptrcast(cx, llconst, llunitty);
assert_eq!(abi::slice_elt_base, 0);
assert_eq!(abi::slice_elt_len, 1);
llconst = C_struct(cx, [
llptr,
C_uint(cx, len)
], false);
}
_ => cx.sess().span_bug(e.span,
format!("unimplemented type in const unsize: {}",
ty_to_string(cx.tcx(), ty)).as_slice())
}
}
_ => {
cx.sess()
.span_bug(e.span,
format!("unimplemented const \
autoref {:?}",
autoref).as_slice())
}
}
}
}
}
}
}
}
let llty = type_of::sizing_type_of(cx, ety_adjusted);
let csize = machine::llsize_of_alloc(cx, val_ty(llconst));
let tsize = machine::llsize_of_alloc(cx, llty);
if csize != tsize {
unsafe {
// FIXME these values could use some context
llvm::LLVMDumpValue(llconst);
llvm::LLVMDumpValue(C_undef(llty));
}
cx.sess().bug(format!("const {} of type {} has size {} instead of {}",
e.repr(cx.tcx()), ty_to_string(cx.tcx(), ety),
csize, tsize).as_slice());
}
(llconst, inlineable, ety_adjusted)
}
// the bool returned is whether this expression can be inlined into other crates
// if it's assigned to a static.
fn const_expr_unadjusted(cx: &CrateContext, e: &ast::Expr,
is_local: bool) -> (ValueRef, bool) {
let map_list = |exprs: &[P<ast::Expr>]| {
exprs.iter().map(|e| first_two(const_expr(cx, &**e, is_local)))
.fold((Vec::new(), true),
|(l, all_inlineable), (val, inlineable)| {
(l.append_one(val), all_inlineable && inlineable)
})
};
unsafe {
let _icx = push_ctxt("const_expr");
return match e.node {
ast::ExprLit(ref lit) => {
(consts::const_lit(cx, e, &**lit), true)
}
ast::ExprBinary(b, ref e1, ref e2) => {
let (te1, _, _) = const_expr(cx, &**e1, is_local);
let (te2, _, _) = const_expr(cx, &**e2, is_local);
let te2 = base::cast_shift_const_rhs(b, te1, te2);
/* Neither type is bottom, and we expect them to be unified
* already, so the following is safe. */
let ty = ty::expr_ty(cx.tcx(), &**e1);
let is_float = ty::type_is_fp(ty);
let signed = ty::type_is_signed(ty);
return (match b {
ast::BiAdd => {
if is_float { llvm::LLVMConstFAdd(te1, te2) }
else { llvm::LLVMConstAdd(te1, te2) }
}
ast::BiSub => {
if is_float { llvm::LLVMConstFSub(te1, te2) }
else { llvm::LLVMConstSub(te1, te2) }
}
ast::BiMul => {
if is_float { llvm::LLVMConstFMul(te1, te2) }
else { llvm::LLVMConstMul(te1, te2) }
}
ast::BiDiv => {
if is_float { llvm::LLVMConstFDiv(te1, te2) }
else if signed { llvm::LLVMConstSDiv(te1, te2) }
else { llvm::LLVMConstUDiv(te1, te2) }
}
ast::BiRem => {
if is_float { llvm::LLVMConstFRem(te1, te2) }
else if signed { llvm::LLVMConstSRem(te1, te2) }
else { 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 => llvm::LLVMConstShl(te1, te2),
ast::BiShr => {
if signed { llvm::LLVMConstAShr(te1, te2) }
else { llvm::LLVMConstLShr(te1, te2) }
}
ast::BiEq => {
if is_float { ConstFCmp(RealOEQ, te1, te2) }
else { ConstICmp(IntEQ, te1, te2) }
},
ast::BiLt => {
if is_float { ConstFCmp(RealOLT, te1, te2) }
else {
if signed { ConstICmp(IntSLT, te1, te2) }
else { ConstICmp(IntULT, te1, te2) }
}
},
ast::BiLe => {
if is_float { ConstFCmp(RealOLE, te1, te2) }
else {
if signed { ConstICmp(IntSLE, te1, te2) }
else { ConstICmp(IntULE, te1, te2) }
}
},
ast::BiNe => {
if is_float { ConstFCmp(RealONE, te1, te2) }
else { ConstICmp(IntNE, te1, te2) }
},
ast::BiGe => {
if is_float { ConstFCmp(RealOGE, te1, te2) }
else {
if signed { ConstICmp(IntSGE, te1, te2) }
else { ConstICmp(IntUGE, te1, te2) }
}
},
ast::BiGt => {
if is_float { ConstFCmp(RealOGT, te1, te2) }
else {
if signed { ConstICmp(IntSGT, te1, te2) }
else { ConstICmp(IntUGT, te1, te2) }
}
},
}, true)
},
ast::ExprUnary(u, ref e) => {
let (te, _, _) = const_expr(cx, &**e, is_local);
let ty = ty::expr_ty(cx.tcx(), &**e);
let is_float = ty::type_is_fp(ty);
return (match u {
ast::UnBox | ast::UnUniq | ast::UnDeref => {
let (dv, _dt) = const_deref(cx, te, ty, true);
dv
}
ast::UnNot => llvm::LLVMConstNot(te),
ast::UnNeg => {
if is_float { llvm::LLVMConstFNeg(te) }
else { llvm::LLVMConstNeg(te) }
}
}, true)
}
ast::ExprField(ref base, field, _) => {
let (bv, inlineable, bt) = const_expr(cx, &**base, is_local);
let brepr = adt::represent_type(cx, bt);
expr::with_field_tys(cx.tcx(), bt, None, |discr, field_tys| {
let ix = ty::field_idx_strict(cx.tcx(), field.node.name, field_tys);
(adt::const_get_field(cx, &*brepr, bv, discr, ix), inlineable)
})
}
ast::ExprTupField(ref base, idx, _) => {
let (bv, inlineable, bt) = const_expr(cx, &**base, is_local);
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), inlineable)
})
}
ast::ExprIndex(ref base, ref index) => {
let (bv, inlineable, bt) = const_expr(cx, &**base, is_local);
let iv = match const_eval::eval_const_expr(cx.tcx(), &**index) {
const_eval::const_int(i) => i as u64,
const_eval::const_uint(u) => u,
_ => cx.sess().span_bug(index.span,
"index is not an integer-constant expression")
};
let (arr, len) = match ty::get(bt).sty {
ty::ty_vec(_, Some(u)) => (bv, C_uint(cx, u)),
ty::ty_open(ty) => match ty::get(ty).sty {
ty::ty_vec(_, None) | ty::ty_str => {
let e1 = const_get_elt(cx, bv, [0]);
(const_deref_ptr(cx, e1), const_get_elt(cx, bv, [1]))
},
_ => cx.sess().span_bug(base.span,
format!("index-expr base must be a vector \
or string type, found {}",
ty_to_string(cx.tcx(), bt)).as_slice())
},
ty::ty_rptr(_, mt) => match ty::get(mt.ty).sty {
ty::ty_vec(_, Some(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 {}",
ty_to_string(cx.tcx(), bt)).as_slice())
},
_ => cx.sess().span_bug(base.span,
format!("index-expr base must be a vector \
or string type, found {}",
ty_to_string(cx.tcx(), bt)).as_slice())
};
let len = llvm::LLVMConstIntGetZExtValue(len) as u64;
let len = match ty::get(bt).sty {
ty::ty_uniq(ty) | ty::ty_rptr(_, ty::mt{ty, ..}) => match ty::get(ty).sty {
ty::ty_str => {
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");
}
(const_get_elt(cx, arr, [iv as c_uint]), inlineable)
}
ast::ExprCast(ref base, _) => {
let ety = ty::expr_ty(cx.tcx(), e);
let llty = type_of::type_of(cx, ety);
let (v, inlineable, basety) = const_expr(cx, &**base, is_local);
return (match (expr::cast_type_kind(cx.tcx(), basety),
expr::cast_type_kind(cx.tcx(), ety)) {
(expr::cast_integral, expr::cast_integral) => {
let s = ty::type_is_signed(basety) as Bool;
llvm::LLVMConstIntCast(v, llty.to_ref(), s)
}
(expr::cast_integral, expr::cast_float) => {
if ty::type_is_signed(basety) {
llvm::LLVMConstSIToFP(v, llty.to_ref())
} else {
llvm::LLVMConstUIToFP(v, llty.to_ref())
}
}
(expr::cast_float, expr::cast_float) => {
llvm::LLVMConstFPCast(v, llty.to_ref())
}
(expr::cast_float, expr::cast_integral) => {
if ty::type_is_signed(ety) { llvm::LLVMConstFPToSI(v, llty.to_ref()) }
else { llvm::LLVMConstFPToUI(v, llty.to_ref()) }
}
(expr::cast_enum, expr::cast_integral) => {
let repr = adt::represent_type(cx, basety);
let discr = adt::const_get_discrim(cx, &*repr, v);
let iv = C_integral(cx.int_type(), discr, false);
let ety_cast = expr::cast_type_kind(cx.tcx(), ety);
match ety_cast {
expr::cast_integral => {
let s = ty::type_is_signed(ety) as Bool;
llvm::LLVMConstIntCast(iv, llty.to_ref(), s)
}
_ => cx.sess().bug("enum cast destination is not \
integral")
}
}
(expr::cast_pointer, expr::cast_pointer) => {
llvm::LLVMConstPointerCast(v, llty.to_ref())
}
(expr::cast_integral, expr::cast_pointer) => {
llvm::LLVMConstIntToPtr(v, llty.to_ref())
}
_ => {
cx.sess().impossible_case(e.span,
"bad combination of types for cast")
}
}, inlineable)
}
ast::ExprAddrOf(mutbl, ref sub) => {
let (e, _, _) = const_expr(cx, &**sub, is_local);
(const_addr_of(cx, e, mutbl), false)
}
ast::ExprTup(ref es) => {
let ety = ty::expr_ty(cx.tcx(), e);
let repr = adt::represent_type(cx, ety);
let (vals, inlineable) = map_list(es.as_slice());
(adt::trans_const(cx, &*repr, 0, vals.as_slice()), inlineable)
}
ast::ExprStruct(_, ref fs, ref base_opt) => {
let ety = ty::expr_ty(cx.tcx(), e);
let repr = adt::represent_type(cx, ety);
let tcx = cx.tcx();
let base_val = match *base_opt {
Some(ref base) => Some(const_expr(cx, &**base, is_local)),
None => None
};
expr::with_field_tys(tcx, ety, Some(e.id), |discr, field_tys| {
let (cs, inlineable) = vec::unzip(field_tys.iter().enumerate()
.map(|(ix, &field_ty)| {
match fs.iter().find(|f| field_ty.ident.name == f.ident.node.name) {
Some(ref f) => first_two(const_expr(cx, &*f.expr, is_local)),
None => {
match base_val {
Some((bv, inlineable, _)) => {
(adt::const_get_field(cx, &*repr, bv, discr, ix),
inlineable)
}
None => cx.sess().span_bug(e.span, "missing struct field")
}
}
}
}));
(adt::trans_const(cx, &*repr, discr, cs.as_slice()),
inlineable.iter().fold(true, |a, &b| a && b))
})
}
ast::ExprVec(ref es) => {
let (v, _, inlineable) = const_vec(cx,
e,
es.as_slice(),
is_local);
(v, inlineable)
}
ast::ExprRepeat(ref elem, ref count) => {
let vec_ty = ty::expr_ty(cx.tcx(), e);
let unit_ty = ty::sequence_element_type(cx.tcx(), vec_ty);
let llunitty = type_of::type_of(cx, unit_ty);
let n = match const_eval::eval_const_expr(cx.tcx(), &**count) {
const_eval::const_int(i) => i as uint,
const_eval::const_uint(i) => i as uint,
_ => cx.sess().span_bug(count.span, "count must be integral const expression.")
};
let vs = Vec::from_elem(n, const_expr(cx, &**elem, is_local).val0());
let v = if vs.iter().any(|vi| val_ty(*vi) != llunitty) {
C_struct(cx, vs.as_slice(), false)
} else {
C_array(llunitty, vs.as_slice())
};
(v, true)
}
ast::ExprPath(ref pth) => {
// Assert that there are no type parameters in this path.
assert!(pth.segments.iter().all(|seg| seg.types.is_empty()));
let opt_def = cx.tcx().def_map.borrow().find_copy(&e.id);
match opt_def {
Some(def::DefFn(def_id, _fn_style)) => {
if !ast_util::is_local(def_id) {
let ty = csearch::get_type(cx.tcx(), def_id).ty;
(base::trans_external_path(cx, def_id, ty), true)
} else {
assert!(ast_util::is_local(def_id));
(base::get_item_val(cx, def_id.node), true)
}
}
Some(def::DefStatic(def_id, false)) => {
get_const_val(cx, def_id)
}
Some(def::DefVariant(enum_did, variant_did, _)) => {
let ety = ty::expr_ty(cx.tcx(), e);
let repr = adt::represent_type(cx, ety);
let vinfo = ty::enum_variant_with_id(cx.tcx(),
enum_did,
variant_did);
(adt::trans_const(cx, &*repr, vinfo.disr_val, []), true)
}
Some(def::DefStruct(_)) => {
let ety = ty::expr_ty(cx.tcx(), e);
let llty = type_of::type_of(cx, ety);
(C_null(llty), true)
}
_ => {
cx.sess().span_bug(e.span, "expected a const, fn, struct, or variant def")
}
}
}
ast::ExprCall(ref callee, ref args) => {
let opt_def = cx.tcx().def_map.borrow().find_copy(&callee.id);
match opt_def {
Some(def::DefStruct(_)) => {
let ety = ty::expr_ty(cx.tcx(), e);
let repr = adt::represent_type(cx, ety);
let (arg_vals, inlineable) = map_list(args.as_slice());
(adt::trans_const(cx, &*repr, 0, arg_vals.as_slice()),
inlineable)
}
Some(def::DefVariant(enum_did, variant_did, _)) => {
let ety = ty::expr_ty(cx.tcx(), e);
let repr = adt::represent_type(cx, ety);
let vinfo = ty::enum_variant_with_id(cx.tcx(),
enum_did,
variant_did);
let (arg_vals, inlineable) = map_list(args.as_slice());
(adt::trans_const(cx,
&*repr,
vinfo.disr_val,
arg_vals.as_slice()), inlineable)
}
_ => cx.sess().span_bug(e.span, "expected a struct or variant def")
}
}
ast::ExprParen(ref e) => first_two(const_expr(cx, &**e, is_local)),
ast::ExprBlock(ref block) => {
match block.expr {
Some(ref expr) => first_two(const_expr(cx, &**expr, is_local)),
None => (C_nil(cx), true)
}
}
_ => cx.sess().span_bug(e.span,
"bad constant expression type in consts::const_expr")
};
}
}
pub fn trans_const(ccx: &CrateContext, m: ast::Mutability, id: ast::NodeId) {
unsafe {
let _icx = push_ctxt("trans_const");
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.const_values().borrow().get_copy(&id);
llvm::LLVMSetInitializer(g, v);
// `get_item_val` left `g` with external linkage, but we just set an
// initializer for it. But we don't know yet if `g` should really be
// defined in this compilation unit, so we set its linkage to
// `AvailableExternallyLinkage`. (It's still a definition, but acts
// like a declaration for most purposes.) If `g` really should be
// declared here, then `trans_item` will fix up the linkage later on.
llvm::SetLinkage(g, llvm::AvailableExternallyLinkage);
if m != ast::MutMutable {
llvm::LLVMSetGlobalConstant(g, True);
}
debuginfo::create_global_var_metadata(ccx, id, g);
}
}