1 // Copyright 2012 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
14 use llvm::{ConstFCmp, ConstICmp, SetLinkage, SetUnnamedAddr};
15 use llvm::{InternalLinkage, ValueRef, Bool, True};
16 use middle::{check_const, def};
17 use middle::cstore::LOCAL_CRATE;
18 use middle::const_eval::{self, ConstVal, ConstEvalErr};
19 use middle::const_eval::{const_int_checked_neg, const_uint_checked_neg};
20 use middle::const_eval::{const_int_checked_add, const_uint_checked_add};
21 use middle::const_eval::{const_int_checked_sub, const_uint_checked_sub};
22 use middle::const_eval::{const_int_checked_mul, const_uint_checked_mul};
23 use middle::const_eval::{const_int_checked_div, const_uint_checked_div};
24 use middle::const_eval::{const_int_checked_rem, const_uint_checked_rem};
25 use middle::const_eval::{const_int_checked_shl, const_uint_checked_shl};
26 use middle::const_eval::{const_int_checked_shr, const_uint_checked_shr};
27 use middle::const_eval::EvalHint::ExprTypeChecked;
28 use middle::const_eval::eval_const_expr_partial;
29 use middle::def_id::DefId;
30 use trans::{adt, closure, debuginfo, expr, inline, machine};
31 use trans::base::{self, push_ctxt};
32 use trans::common::{self, type_is_sized, ExprOrMethodCall, node_id_substs, C_nil, const_get_elt};
33 use trans::common::{CrateContext, C_integral, C_floating, C_bool, C_str_slice, C_bytes, val_ty};
34 use trans::common::C_floating_f64;
35 use trans::common::{C_struct, C_undef, const_to_opt_int, const_to_opt_uint, VariantInfo, C_uint};
36 use trans::common::{type_is_fat_ptr, Field, C_vector, C_array, C_null, ExprId, MethodCallKey};
38 use trans::monomorphize;
39 use trans::type_::Type;
41 use middle::subst::Substs;
42 use middle::ty::adjustment::{AdjustDerefRef, AdjustReifyFnPointer};
43 use middle::ty::adjustment::AdjustUnsafeFnPointer;
44 use middle::ty::{self, Ty};
45 use middle::ty::cast::{CastTy,IntTy};
46 use util::nodemap::NodeMap;
50 use std::ffi::{CStr, CString};
55 use syntax::parse::token;
58 pub type FnArgMap<'a> = Option<&'a NodeMap<ValueRef>>;
60 pub fn const_lit(cx: &CrateContext, e: &hir::Expr, lit: &ast::Lit)
62 let _icx = push_ctxt("trans_lit");
63 debug!("const_lit: {:?}", lit);
65 ast::LitByte(b) => C_integral(Type::uint_from_ty(cx, ast::TyU8), b as u64, false),
66 ast::LitChar(i) => C_integral(Type::char(cx), i as u64, false),
67 ast::LitInt(i, ast::SignedIntLit(t, _)) => {
68 C_integral(Type::int_from_ty(cx, t), i, true)
70 ast::LitInt(u, ast::UnsignedIntLit(t)) => {
71 C_integral(Type::uint_from_ty(cx, t), u, false)
73 ast::LitInt(i, ast::UnsuffixedIntLit(_)) => {
74 let lit_int_ty = cx.tcx().node_id_to_type(e.id);
75 match lit_int_ty.sty {
77 C_integral(Type::int_from_ty(cx, t), i as u64, true)
80 C_integral(Type::uint_from_ty(cx, t), i as u64, false)
82 _ => cx.sess().span_bug(lit.span,
83 &format!("integer literal has type {:?} (expected int \
88 ast::LitFloat(ref fs, t) => {
89 C_floating(&fs, Type::float_from_ty(cx, t))
91 ast::LitFloatUnsuffixed(ref fs) => {
92 let lit_float_ty = cx.tcx().node_id_to_type(e.id);
93 match lit_float_ty.sty {
95 C_floating(&fs, Type::float_from_ty(cx, t))
98 cx.sess().span_bug(lit.span,
99 "floating point literal doesn't have the right type");
103 ast::LitBool(b) => C_bool(cx, b),
104 ast::LitStr(ref s, _) => C_str_slice(cx, (*s).clone()),
105 ast::LitByteStr(ref data) => {
106 addr_of(cx, C_bytes(cx, &data[..]), 1, "byte_str")
111 pub fn trans_constval<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
114 param_substs: &'tcx Substs<'tcx>)
117 let llty = type_of::type_of(ccx, ty);
119 ConstVal::Float(v) => C_floating_f64(v, llty),
120 ConstVal::Bool(v) => C_bool(ccx, v),
121 ConstVal::Int(v) => C_integral(llty, v as u64, true),
122 ConstVal::Uint(v) => C_integral(llty, v, false),
123 ConstVal::Str(ref v) => C_str_slice(ccx, v.clone()),
124 ConstVal::ByteStr(ref v) => addr_of(ccx, C_bytes(ccx, v), 1, "byte_str"),
125 ConstVal::Struct(id) | ConstVal::Tuple(id) => {
126 let expr = ccx.tcx().map.expect_expr(id);
127 match const_expr(ccx, expr, param_substs, None, TrueConst::Yes) {
129 Err(e) => panic!("const eval failure: {}", e.description()),
132 ConstVal::Function(_) => {
135 ConstVal::Array(..) => {
138 ConstVal::Repeat(..) => {
144 pub fn ptrcast(val: ValueRef, ty: Type) -> ValueRef {
146 llvm::LLVMConstPointerCast(val, ty.to_ref())
150 fn addr_of_mut(ccx: &CrateContext,
152 align: machine::llalign,
156 // FIXME: this totally needs a better name generation scheme, perhaps a simple global
157 // counter? Also most other uses of gensym in trans.
158 let gsym = token::gensym("_");
159 let name = format!("{}{}", kind, gsym.0);
160 let gv = declare::define_global(ccx, &name[..], val_ty(cv)).unwrap_or_else(||{
161 ccx.sess().bug(&format!("symbol `{}` is already defined", name));
163 llvm::LLVMSetInitializer(gv, cv);
164 llvm::LLVMSetAlignment(gv, align);
165 SetLinkage(gv, InternalLinkage);
166 SetUnnamedAddr(gv, true);
171 pub fn addr_of(ccx: &CrateContext,
173 align: machine::llalign,
176 match ccx.const_globals().borrow().get(&cv) {
179 // Upgrade the alignment in cases where the same constant is used with different
180 // alignment requirements
181 if align > llvm::LLVMGetAlignment(gv) {
182 llvm::LLVMSetAlignment(gv, align);
189 let gv = addr_of_mut(ccx, cv, align, kind);
191 llvm::LLVMSetGlobalConstant(gv, True);
193 ccx.const_globals().borrow_mut().insert(cv, gv);
197 fn const_deref_ptr(cx: &CrateContext, v: ValueRef) -> ValueRef {
198 let v = match cx.const_unsized().borrow().get(&v) {
203 llvm::LLVMGetInitializer(v)
207 fn const_deref<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
210 -> (ValueRef, Ty<'tcx>) {
211 match ty.builtin_deref(true, ty::NoPreference) {
213 if type_is_sized(cx.tcx(), mt.ty) {
214 (const_deref_ptr(cx, v), mt.ty)
216 // Derefing a fat pointer does not change the representation,
217 // just the type to the unsized contents.
222 cx.sess().bug(&format!("unexpected dereferenceable type {:?}",
228 fn const_fn_call<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
229 node: ExprOrMethodCall,
231 arg_vals: &[ValueRef],
232 param_substs: &'tcx Substs<'tcx>,
233 trueconst: TrueConst) -> Result<ValueRef, ConstEvalFailure> {
234 let fn_like = const_eval::lookup_const_fn_by_id(ccx.tcx(), def_id);
235 let fn_like = fn_like.expect("lookup_const_fn_by_id failed in const_fn_call");
237 let args = &fn_like.decl().inputs;
238 assert_eq!(args.len(), arg_vals.len());
240 let arg_ids = args.iter().map(|arg| arg.pat.id);
241 let fn_args = arg_ids.zip(arg_vals.iter().cloned()).collect();
243 let substs = ccx.tcx().mk_substs(node_id_substs(ccx, node, param_substs));
244 match fn_like.body().expr {
246 const_expr(ccx, &**expr, substs, Some(&fn_args), trueconst).map(|(res, _)| res)
248 None => Ok(C_nil(ccx)),
252 pub fn get_const_expr<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
254 ref_expr: &hir::Expr)
256 let def_id = inline::maybe_instantiate_inline(ccx, def_id);
258 if def_id.krate != LOCAL_CRATE {
259 ccx.sess().span_bug(ref_expr.span,
260 "cross crate constant could not be inlined");
263 match const_eval::lookup_const_by_id(ccx.tcx(), def_id, Some(ref_expr.id)) {
264 Some(ref expr) => expr,
266 ccx.sess().span_bug(ref_expr.span, "constant item not found")
271 pub enum ConstEvalFailure {
272 /// in case the const evaluator failed on something that panic at runtime
273 /// as defined in RFC 1229
274 Runtime(ConstEvalErr),
275 // in case we found a true constant
276 Compiletime(ConstEvalErr),
279 impl ConstEvalFailure {
280 fn into_inner(self) -> ConstEvalErr {
286 pub fn description(&self) -> Cow<str> {
288 &Runtime(ref e) => e.description(),
289 &Compiletime(ref e) => e.description(),
294 #[derive(Copy, Clone)]
299 use self::ConstEvalFailure::*;
301 fn get_const_val(ccx: &CrateContext,
303 ref_expr: &hir::Expr) -> Result<ValueRef, ConstEvalFailure> {
304 let expr = get_const_expr(ccx, def_id, ref_expr);
305 let empty_substs = ccx.tcx().mk_substs(Substs::trans_empty());
306 match get_const_expr_as_global(ccx, expr, check_const::ConstQualif::empty(),
307 empty_substs, TrueConst::Yes) {
308 Err(Runtime(err)) => {
309 ccx.tcx().sess.span_err(expr.span, &err.description());
310 Err(Compiletime(err))
316 pub fn get_const_expr_as_global<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
318 qualif: check_const::ConstQualif,
319 param_substs: &'tcx Substs<'tcx>,
320 trueconst: TrueConst)
321 -> Result<ValueRef, ConstEvalFailure> {
322 debug!("get_const_expr_as_global: {:?}", expr.id);
323 // Special-case constants to cache a common global for all uses.
325 hir::ExprPath(..) => {
326 let def = ccx.tcx().def_map.borrow().get(&expr.id).unwrap().full_def();
328 def::DefConst(def_id) | def::DefAssociatedConst(def_id) => {
329 if !ccx.tcx().tables.borrow().adjustments.contains_key(&expr.id) {
330 debug!("get_const_expr_as_global ({:?}): found const {:?}",
332 return get_const_val(ccx, def_id, expr);
341 let key = (expr.id, param_substs);
342 match ccx.const_values().borrow().get(&key) {
343 Some(&val) => return Ok(val),
346 let ty = monomorphize::apply_param_substs(ccx.tcx(), param_substs,
347 &ccx.tcx().expr_ty(expr));
348 let val = if qualif.intersects(check_const::ConstQualif::NON_STATIC_BORROWS) {
349 // Avoid autorefs as they would create global instead of stack
350 // references, even when only the latter are correct.
351 try!(const_expr_unadjusted(ccx, expr, ty, param_substs, None, trueconst))
353 match const_expr(ccx, expr, param_substs, None, trueconst) {
354 Err(err) => return Err(err),
359 // boolean SSA values are i1, but they have to be stored in i8 slots,
360 // otherwise some LLVM optimization passes don't work as expected
362 if llvm::LLVMTypeOf(val) == Type::i1(ccx).to_ref() {
363 llvm::LLVMConstZExt(val, Type::i8(ccx).to_ref())
369 let lvalue = addr_of(ccx, val, type_of::align_of(ccx, ty), "const");
370 ccx.const_values().borrow_mut().insert(key, lvalue);
374 pub fn const_expr<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
376 param_substs: &'tcx Substs<'tcx>,
378 trueconst: TrueConst)
379 -> Result<(ValueRef, Ty<'tcx>), ConstEvalFailure> {
380 let ety = monomorphize::apply_param_substs(cx.tcx(), param_substs,
381 &cx.tcx().expr_ty(e));
382 let llconst = try!(const_expr_unadjusted(cx, e, ety, param_substs, fn_args, trueconst));
383 let mut llconst = llconst;
384 let mut ety_adjusted = monomorphize::apply_param_substs(cx.tcx(), param_substs,
385 &cx.tcx().expr_ty_adjusted(e));
386 let opt_adj = cx.tcx().tables.borrow().adjustments.get(&e.id).cloned();
388 Some(AdjustReifyFnPointer) => {
389 // FIXME(#19925) once fn item types are
390 // zero-sized, we'll need to do something here
392 Some(AdjustUnsafeFnPointer) => {
393 // purely a type-level thing
395 Some(AdjustDerefRef(adj)) => {
397 // Save the last autoderef in case we can avoid it.
398 if adj.autoderefs > 0 {
399 for _ in 0..adj.autoderefs-1 {
400 let (dv, dt) = const_deref(cx, llconst, ty);
406 if adj.autoref.is_some() {
407 if adj.autoderefs == 0 {
408 // Don't copy data to do a deref+ref
409 // (i.e., skip the last auto-deref).
410 llconst = addr_of(cx, llconst, type_of::align_of(cx, ty), "autoref");
411 ty = cx.tcx().mk_imm_ref(cx.tcx().mk_region(ty::ReStatic), ty);
414 let (dv, dt) = const_deref(cx, llconst, ty);
417 // If we derefed a fat pointer then we will have an
418 // open type here. So we need to update the type with
419 // the one returned from const_deref.
423 if let Some(target) = adj.unsize {
424 let target = monomorphize::apply_param_substs(cx.tcx(),
428 let pointee_ty = ty.builtin_deref(true, ty::NoPreference)
429 .expect("consts: unsizing got non-pointer type").ty;
430 let (base, old_info) = if !type_is_sized(cx.tcx(), pointee_ty) {
431 // Normally, the source is a thin pointer and we are
432 // adding extra info to make a fat pointer. The exception
433 // is when we are upcasting an existing object fat pointer
434 // to use a different vtable. In that case, we want to
435 // load out the original data pointer so we can repackage
437 (const_get_elt(cx, llconst, &[abi::FAT_PTR_ADDR as u32]),
438 Some(const_get_elt(cx, llconst, &[abi::FAT_PTR_EXTRA as u32])))
443 let unsized_ty = target.builtin_deref(true, ty::NoPreference)
444 .expect("consts: unsizing got non-pointer target type").ty;
445 let ptr_ty = type_of::in_memory_type_of(cx, unsized_ty).ptr_to();
446 let base = ptrcast(base, ptr_ty);
447 let info = base::unsized_info(cx, pointee_ty, unsized_ty,
448 old_info, param_substs);
450 if old_info.is_none() {
451 let prev_const = cx.const_unsized().borrow_mut()
452 .insert(base, llconst);
453 assert!(prev_const.is_none() || prev_const == Some(llconst));
455 assert_eq!(abi::FAT_PTR_ADDR, 0);
456 assert_eq!(abi::FAT_PTR_EXTRA, 1);
457 llconst = C_struct(cx, &[base, info], false);
463 let llty = type_of::sizing_type_of(cx, ety_adjusted);
464 let csize = machine::llsize_of_alloc(cx, val_ty(llconst));
465 let tsize = machine::llsize_of_alloc(cx, llty);
467 cx.sess().abort_if_errors();
469 // FIXME these values could use some context
470 llvm::LLVMDumpValue(llconst);
471 llvm::LLVMDumpValue(C_undef(llty));
473 cx.sess().bug(&format!("const {:?} of type {:?} has size {} instead of {}",
477 Ok((llconst, ety_adjusted))
480 fn check_unary_expr_validity(cx: &CrateContext, e: &hir::Expr, t: Ty,
481 te: ValueRef, trueconst: TrueConst) -> Result<(), ConstEvalFailure> {
482 // The only kind of unary expression that we check for validity
483 // here is `-expr`, to check if it "overflows" (e.g. `-i32::MIN`).
484 if let hir::ExprUnary(hir::UnNeg, ref inner_e) = e.node {
486 // An unfortunate special case: we parse e.g. -128 as a
487 // negation of the literal 128, which means if we're expecting
488 // a i8 (or if it was already suffixed, e.g. `-128_i8`), then
489 // 128 will have already overflowed to -128, and so then the
490 // constant evaluator thinks we're trying to negate -128.
492 // Catch this up front by looking for ExprLit directly,
493 // and just accepting it.
494 if let hir::ExprLit(_) = inner_e.node { return Ok(()); }
496 let result = match t.sty {
497 ty::TyInt(int_type) => {
498 let input = match const_to_opt_int(te) {
500 None => return Ok(()),
502 const_int_checked_neg(
503 input, e, Some(const_eval::IntTy::from(cx.tcx(), int_type)))
505 ty::TyUint(uint_type) => {
506 let input = match const_to_opt_uint(te) {
508 None => return Ok(()),
510 const_uint_checked_neg(
511 input, e, Some(const_eval::UintTy::from(cx.tcx(), uint_type)))
515 const_err(cx, e, result, trueconst)
521 fn const_err(cx: &CrateContext,
523 result: Result<ConstVal, ConstEvalErr>,
524 trueconst: TrueConst)
525 -> Result<(), ConstEvalFailure> {
526 match (result, trueconst) {
528 // We do not actually care about a successful result.
531 (Err(err), TrueConst::Yes) => {
532 cx.tcx().sess.span_err(e.span, &err.description());
533 Err(Compiletime(err))
535 (Err(err), TrueConst::No) => {
536 cx.tcx().sess.span_warn(e.span, &err.description());
542 fn check_binary_expr_validity(cx: &CrateContext, e: &hir::Expr, t: Ty,
543 te1: ValueRef, te2: ValueRef,
544 trueconst: TrueConst) -> Result<(), ConstEvalFailure> {
545 let b = if let hir::ExprBinary(b, _, _) = e.node { b } else { unreachable!() };
547 let result = match t.sty {
548 ty::TyInt(int_type) => {
549 let (lhs, rhs) = match (const_to_opt_int(te1),
550 const_to_opt_int(te2)) {
551 (Some(v1), Some(v2)) => (v1, v2),
555 let opt_ety = Some(const_eval::IntTy::from(cx.tcx(), int_type));
557 hir::BiAdd => const_int_checked_add(lhs, rhs, e, opt_ety),
558 hir::BiSub => const_int_checked_sub(lhs, rhs, e, opt_ety),
559 hir::BiMul => const_int_checked_mul(lhs, rhs, e, opt_ety),
560 hir::BiDiv => const_int_checked_div(lhs, rhs, e, opt_ety),
561 hir::BiRem => const_int_checked_rem(lhs, rhs, e, opt_ety),
562 hir::BiShl => const_int_checked_shl(lhs, rhs, e, opt_ety),
563 hir::BiShr => const_int_checked_shr(lhs, rhs, e, opt_ety),
567 ty::TyUint(uint_type) => {
568 let (lhs, rhs) = match (const_to_opt_uint(te1),
569 const_to_opt_uint(te2)) {
570 (Some(v1), Some(v2)) => (v1, v2),
574 let opt_ety = Some(const_eval::UintTy::from(cx.tcx(), uint_type));
576 hir::BiAdd => const_uint_checked_add(lhs, rhs, e, opt_ety),
577 hir::BiSub => const_uint_checked_sub(lhs, rhs, e, opt_ety),
578 hir::BiMul => const_uint_checked_mul(lhs, rhs, e, opt_ety),
579 hir::BiDiv => const_uint_checked_div(lhs, rhs, e, opt_ety),
580 hir::BiRem => const_uint_checked_rem(lhs, rhs, e, opt_ety),
581 hir::BiShl => const_uint_checked_shl(lhs, rhs, e, opt_ety),
582 hir::BiShr => const_uint_checked_shr(lhs, rhs, e, opt_ety),
588 const_err(cx, e, result, trueconst)
591 fn const_expr_unadjusted<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
594 param_substs: &'tcx Substs<'tcx>,
596 trueconst: TrueConst)
597 -> Result<ValueRef, ConstEvalFailure>
599 debug!("const_expr_unadjusted(e={:?}, ety={:?}, param_substs={:?})",
604 let map_list = |exprs: &[P<hir::Expr>]| -> Result<Vec<ValueRef>, ConstEvalFailure> {
606 .map(|e| const_expr(cx, &**e, param_substs, fn_args, trueconst).map(|(l, _)| l))
607 .collect::<Vec<Result<ValueRef, ConstEvalFailure>>>()
610 // this dance is necessary to eagerly run const_expr so all errors are reported
612 let _icx = push_ctxt("const_expr");
614 hir::ExprLit(ref lit) => {
615 const_lit(cx, e, &**lit)
617 hir::ExprBinary(b, ref e1, ref e2) => {
618 /* Neither type is bottom, and we expect them to be unified
619 * already, so the following is safe. */
620 let (te1, ty) = try!(const_expr(cx, &**e1, param_substs, fn_args, trueconst));
621 debug!("const_expr_unadjusted: te1={}, ty={:?}",
622 cx.tn().val_to_string(te1),
624 assert!(!ty.is_simd());
625 let is_float = ty.is_fp();
626 let signed = ty.is_signed();
628 let (te2, _) = try!(const_expr(cx, &**e2, param_substs, fn_args, trueconst));
630 try!(check_binary_expr_validity(cx, e, ty, te1, te2, trueconst));
632 unsafe { match b.node {
633 hir::BiAdd if is_float => llvm::LLVMConstFAdd(te1, te2),
634 hir::BiAdd => llvm::LLVMConstAdd(te1, te2),
636 hir::BiSub if is_float => llvm::LLVMConstFSub(te1, te2),
637 hir::BiSub => llvm::LLVMConstSub(te1, te2),
639 hir::BiMul if is_float => llvm::LLVMConstFMul(te1, te2),
640 hir::BiMul => llvm::LLVMConstMul(te1, te2),
642 hir::BiDiv if is_float => llvm::LLVMConstFDiv(te1, te2),
643 hir::BiDiv if signed => llvm::LLVMConstSDiv(te1, te2),
644 hir::BiDiv => llvm::LLVMConstUDiv(te1, te2),
646 hir::BiRem if is_float => llvm::LLVMConstFRem(te1, te2),
647 hir::BiRem if signed => llvm::LLVMConstSRem(te1, te2),
648 hir::BiRem => llvm::LLVMConstURem(te1, te2),
650 hir::BiAnd => llvm::LLVMConstAnd(te1, te2),
651 hir::BiOr => llvm::LLVMConstOr(te1, te2),
652 hir::BiBitXor => llvm::LLVMConstXor(te1, te2),
653 hir::BiBitAnd => llvm::LLVMConstAnd(te1, te2),
654 hir::BiBitOr => llvm::LLVMConstOr(te1, te2),
656 let te2 = base::cast_shift_const_rhs(b.node, te1, te2);
657 llvm::LLVMConstShl(te1, te2)
660 let te2 = base::cast_shift_const_rhs(b.node, te1, te2);
661 if signed { llvm::LLVMConstAShr(te1, te2) }
662 else { llvm::LLVMConstLShr(te1, te2) }
664 hir::BiEq | hir::BiNe | hir::BiLt | hir::BiLe | hir::BiGt | hir::BiGe => {
666 let cmp = base::bin_op_to_fcmp_predicate(cx, b.node);
667 ConstFCmp(cmp, te1, te2)
669 let cmp = base::bin_op_to_icmp_predicate(cx, b.node, signed);
670 ConstICmp(cmp, te1, te2)
673 } } // unsafe { match b.node {
675 hir::ExprUnary(u, ref inner_e) => {
676 let (te, ty) = try!(const_expr(cx, &**inner_e, param_substs, fn_args, trueconst));
678 try!(check_unary_expr_validity(cx, e, ty, te, trueconst));
680 let is_float = ty.is_fp();
682 hir::UnDeref => const_deref(cx, te, ty).0,
683 hir::UnNot => llvm::LLVMConstNot(te),
684 hir::UnNeg if is_float => llvm::LLVMConstFNeg(te),
685 hir::UnNeg => llvm::LLVMConstNeg(te),
688 hir::ExprField(ref base, field) => {
689 let (bv, bt) = try!(const_expr(cx, &**base, param_substs, fn_args, trueconst));
690 let brepr = adt::represent_type(cx, bt);
691 let vinfo = VariantInfo::from_ty(cx.tcx(), bt, None);
692 let ix = vinfo.field_index(field.node);
693 adt::const_get_field(cx, &*brepr, bv, vinfo.discr, ix)
695 hir::ExprTupField(ref base, idx) => {
696 let (bv, bt) = try!(const_expr(cx, &**base, param_substs, fn_args, trueconst));
697 let brepr = adt::represent_type(cx, bt);
698 let vinfo = VariantInfo::from_ty(cx.tcx(), bt, None);
699 adt::const_get_field(cx, &*brepr, bv, vinfo.discr, idx.node)
701 hir::ExprIndex(ref base, ref index) => {
702 let (bv, bt) = try!(const_expr(cx, &**base, param_substs, fn_args, trueconst));
703 let iv = match eval_const_expr_partial(cx.tcx(), &index, ExprTypeChecked, None) {
704 Ok(ConstVal::Int(i)) => i as u64,
705 Ok(ConstVal::Uint(u)) => u,
706 _ => cx.sess().span_bug(index.span,
707 "index is not an integer-constant expression")
709 let (arr, len) = match bt.sty {
710 ty::TyArray(_, u) => (bv, C_uint(cx, u)),
711 ty::TySlice(_) | ty::TyStr => {
712 let e1 = const_get_elt(cx, bv, &[0]);
713 (const_deref_ptr(cx, e1), const_get_elt(cx, bv, &[1]))
715 ty::TyRef(_, mt) => match mt.ty.sty {
716 ty::TyArray(_, u) => {
717 (const_deref_ptr(cx, bv), C_uint(cx, u))
719 _ => cx.sess().span_bug(base.span,
720 &format!("index-expr base must be a vector \
721 or string type, found {:?}",
724 _ => cx.sess().span_bug(base.span,
725 &format!("index-expr base must be a vector \
726 or string type, found {:?}",
730 let len = unsafe { llvm::LLVMConstIntGetZExtValue(len) as u64 };
731 let len = match bt.sty {
732 ty::TyBox(ty) | ty::TyRef(_, ty::TypeAndMut{ty, ..}) => match ty.sty {
742 // FIXME #3170: report this earlier on in the const-eval
743 // pass. Reporting here is a bit late.
744 span_err!(cx.sess(), e.span, E0515,
745 "const index-expr is out of bounds");
746 C_undef(val_ty(arr).element_type())
748 const_get_elt(cx, arr, &[iv as c_uint])
751 hir::ExprCast(ref base, _) => {
753 let llty = type_of::type_of(cx, t_cast);
754 let (v, t_expr) = try!(const_expr(cx, &**base, param_substs, fn_args, trueconst));
755 debug!("trans_const_cast({:?} as {:?})", t_expr, t_cast);
756 if expr::cast_is_noop(cx.tcx(), base, t_expr, t_cast) {
759 if type_is_fat_ptr(cx.tcx(), t_expr) {
760 // Fat pointer casts.
762 t_cast.builtin_deref(true, ty::NoPreference).expect("cast to non-pointer").ty;
763 let ptr_ty = type_of::in_memory_type_of(cx, t_cast_inner).ptr_to();
764 let addr = ptrcast(const_get_elt(cx, v, &[abi::FAT_PTR_ADDR as u32]),
766 if type_is_fat_ptr(cx.tcx(), t_cast) {
767 let info = const_get_elt(cx, v, &[abi::FAT_PTR_EXTRA as u32]);
768 return Ok(C_struct(cx, &[addr, info], false))
774 CastTy::from_ty(t_expr).expect("bad input type for cast"),
775 CastTy::from_ty(t_cast).expect("bad output type for cast"),
777 (CastTy::Int(IntTy::CEnum), CastTy::Int(_)) => {
778 let repr = adt::represent_type(cx, t_expr);
779 let discr = adt::const_get_discrim(cx, &*repr, v);
780 let iv = C_integral(cx.int_type(), discr, false);
781 let s = adt::is_discr_signed(&*repr) as Bool;
782 llvm::LLVMConstIntCast(iv, llty.to_ref(), s)
784 (CastTy::Int(_), CastTy::Int(_)) => {
785 let s = t_expr.is_signed() as Bool;
786 llvm::LLVMConstIntCast(v, llty.to_ref(), s)
788 (CastTy::Int(_), CastTy::Float) => {
789 if t_expr.is_signed() {
790 llvm::LLVMConstSIToFP(v, llty.to_ref())
792 llvm::LLVMConstUIToFP(v, llty.to_ref())
795 (CastTy::Float, CastTy::Float) => llvm::LLVMConstFPCast(v, llty.to_ref()),
796 (CastTy::Float, CastTy::Int(IntTy::I)) => llvm::LLVMConstFPToSI(v, llty.to_ref()),
797 (CastTy::Float, CastTy::Int(_)) => llvm::LLVMConstFPToUI(v, llty.to_ref()),
798 (CastTy::Ptr(_), CastTy::Ptr(_)) | (CastTy::FnPtr, CastTy::Ptr(_))
799 | (CastTy::RPtr(_), CastTy::Ptr(_)) => {
802 (CastTy::FnPtr, CastTy::FnPtr) => ptrcast(v, llty), // isn't this a coercion?
803 (CastTy::Int(_), CastTy::Ptr(_)) => llvm::LLVMConstIntToPtr(v, llty.to_ref()),
804 (CastTy::Ptr(_), CastTy::Int(_)) | (CastTy::FnPtr, CastTy::Int(_)) => {
805 llvm::LLVMConstPtrToInt(v, llty.to_ref())
808 cx.sess().impossible_case(e.span,
809 "bad combination of types for cast")
811 } } // unsafe { match ( ... ) {
813 hir::ExprAddrOf(hir::MutImmutable, ref sub) => {
814 // If this is the address of some static, then we need to return
815 // the actual address of the static itself (short circuit the rest
820 hir::ExprBlock(ref blk) => {
821 if let Some(ref sub) = blk.expr {
830 let opt_def = cx.tcx().def_map.borrow().get(&cur.id).map(|d| d.full_def());
831 if let Some(def::DefStatic(def_id, _)) = opt_def {
832 common::get_static_val(cx, def_id, ety)
834 // If this isn't the address of a static, then keep going through
835 // normal constant evaluation.
836 let (v, ty) = try!(const_expr(cx, &**sub, param_substs, fn_args, trueconst));
837 addr_of(cx, v, type_of::align_of(cx, ty), "ref")
840 hir::ExprAddrOf(hir::MutMutable, ref sub) => {
841 let (v, ty) = try!(const_expr(cx, &**sub, param_substs, fn_args, trueconst));
842 addr_of_mut(cx, v, type_of::align_of(cx, ty), "ref_mut_slice")
844 hir::ExprTup(ref es) => {
845 let repr = adt::represent_type(cx, ety);
846 let vals = try!(map_list(&es[..]));
847 adt::trans_const(cx, &*repr, 0, &vals[..])
849 hir::ExprStruct(_, ref fs, ref base_opt) => {
850 let repr = adt::represent_type(cx, ety);
852 let base_val = match *base_opt {
853 Some(ref base) => Some(try!(const_expr(
863 let VariantInfo { discr, fields } = VariantInfo::of_node(cx.tcx(), ety, e.id);
864 let cs = fields.iter().enumerate().map(|(ix, &Field(f_name, _))| {
865 match (fs.iter().find(|f| f_name == f.name.node), base_val) {
866 (Some(ref f), _) => {
867 const_expr(cx, &*f.expr, param_substs, fn_args, trueconst).map(|(l, _)| l)
869 (_, Some((bv, _))) => Ok(adt::const_get_field(cx, &*repr, bv, discr, ix)),
870 (_, None) => cx.sess().span_bug(e.span, "missing struct field"),
873 .collect::<Vec<Result<_, ConstEvalFailure>>>()
875 .collect::<Result<Vec<_>,ConstEvalFailure>>();
880 adt::trans_const(cx, &*repr, discr, &cs[..])
883 hir::ExprVec(ref es) => {
884 let unit_ty = ety.sequence_element_type(cx.tcx());
885 let llunitty = type_of::type_of(cx, unit_ty);
894 .collect::<Vec<Result<_, ConstEvalFailure>>>()
896 .collect::<Result<Vec<_>, ConstEvalFailure>>();
898 // If the vector contains enums, an LLVM array won't work.
899 if vs.iter().any(|vi| val_ty(*vi) != llunitty) {
900 C_struct(cx, &vs[..], false)
902 C_array(llunitty, &vs[..])
905 hir::ExprRepeat(ref elem, ref count) => {
906 let unit_ty = ety.sequence_element_type(cx.tcx());
907 let llunitty = type_of::type_of(cx, unit_ty);
908 let n = cx.tcx().eval_repeat_count(count);
909 let unit_val = try!(const_expr(cx, &**elem, param_substs, fn_args, trueconst)).0;
910 let vs = vec![unit_val; n];
911 if val_ty(unit_val) != llunitty {
912 C_struct(cx, &vs[..], false)
914 C_array(llunitty, &vs[..])
917 hir::ExprPath(..) => {
918 let def = cx.tcx().def_map.borrow().get(&e.id).unwrap().full_def();
920 def::DefLocal(_, id) => {
921 if let Some(val) = fn_args.and_then(|args| args.get(&id).cloned()) {
924 cx.sess().span_bug(e.span, "const fn argument not found")
927 def::DefFn(..) | def::DefMethod(..) => {
928 expr::trans_def_fn_unadjusted(cx, e, def, param_substs).val
930 def::DefConst(def_id) | def::DefAssociatedConst(def_id) => {
931 const_deref_ptr(cx, try!(get_const_val(cx, def_id, e)))
933 def::DefVariant(enum_did, variant_did, _) => {
934 let vinfo = cx.tcx().lookup_adt_def(enum_did).variant_with_id(variant_did);
936 ty::VariantKind::Unit => {
937 let repr = adt::represent_type(cx, ety);
938 adt::trans_const(cx, &*repr, vinfo.disr_val, &[])
940 ty::VariantKind::Tuple => {
941 expr::trans_def_fn_unadjusted(cx, e, def, param_substs).val
943 ty::VariantKind::Struct => {
944 cx.sess().span_bug(e.span, "path-expr refers to a dict variant!")
948 def::DefStruct(_) => {
949 if let ty::TyBareFn(..) = ety.sty {
951 expr::trans_def_fn_unadjusted(cx, e, def, param_substs).val
954 C_null(type_of::type_of(cx, ety))
958 cx.sess().span_bug(e.span, "expected a const, fn, struct, \
963 hir::ExprCall(ref callee, ref args) => {
964 let mut callee = &**callee;
966 callee = match callee.node {
967 hir::ExprBlock(ref block) => match block.expr {
968 Some(ref tail) => &**tail,
974 let def = cx.tcx().def_map.borrow()[&callee.id].full_def();
975 let arg_vals = try!(map_list(args));
977 def::DefFn(did, _) | def::DefMethod(did) => {
987 def::DefStruct(_) => {
989 C_vector(&arg_vals[..])
991 let repr = adt::represent_type(cx, ety);
992 adt::trans_const(cx, &*repr, 0, &arg_vals[..])
995 def::DefVariant(enum_did, variant_did, _) => {
996 let repr = adt::represent_type(cx, ety);
997 let vinfo = cx.tcx().lookup_adt_def(enum_did).variant_with_id(variant_did);
1003 _ => cx.sess().span_bug(e.span, "expected a struct, variant, or const fn def"),
1006 hir::ExprMethodCall(_, _, ref args) => {
1007 let arg_vals = try!(map_list(args));
1008 let method_call = ty::MethodCall::expr(e.id);
1009 let method_did = cx.tcx().tables.borrow().method_map[&method_call].def_id;
1010 try!(const_fn_call(cx, MethodCallKey(method_call),
1011 method_did, &arg_vals, param_substs, trueconst))
1013 hir::ExprBlock(ref block) => {
1015 Some(ref expr) => try!(const_expr(
1025 hir::ExprClosure(_, ref decl, ref body) => {
1027 ty::TyClosure(def_id, ref substs) => {
1028 closure::trans_closure_expr(closure::Dest::Ignore(cx), decl,
1029 body, e.id, def_id, substs);
1034 &format!("bad type for closure expr: {:?}", ety))
1036 C_null(type_of::type_of(cx, ety))
1038 _ => cx.sess().span_bug(e.span,
1039 "bad constant expression type in consts::const_expr"),
1043 pub fn trans_static(ccx: &CrateContext,
1047 attrs: &Vec<ast::Attribute>)
1048 -> Result<ValueRef, ConstEvalErr> {
1050 let _icx = push_ctxt("trans_static");
1051 let g = base::get_item_val(ccx, id);
1053 let empty_substs = ccx.tcx().mk_substs(Substs::trans_empty());
1054 let (v, _) = try!(const_expr(
1060 ).map_err(|e| e.into_inner()));
1062 // boolean SSA values are i1, but they have to be stored in i8 slots,
1063 // otherwise some LLVM optimization passes don't work as expected
1064 let mut val_llty = llvm::LLVMTypeOf(v);
1065 let v = if val_llty == Type::i1(ccx).to_ref() {
1066 val_llty = Type::i8(ccx).to_ref();
1067 llvm::LLVMConstZExt(v, val_llty)
1072 let ty = ccx.tcx().node_id_to_type(id);
1073 let llty = type_of::type_of(ccx, ty);
1074 let g = if val_llty == llty.to_ref() {
1077 // If we created the global with the wrong type,
1078 // correct the type.
1079 let empty_string = CString::new("").unwrap();
1080 let name_str_ref = CStr::from_ptr(llvm::LLVMGetValueName(g));
1081 let name_string = CString::new(name_str_ref.to_bytes()).unwrap();
1082 llvm::LLVMSetValueName(g, empty_string.as_ptr());
1083 let new_g = llvm::LLVMGetOrInsertGlobal(
1084 ccx.llmod(), name_string.as_ptr(), val_llty);
1085 // To avoid breaking any invariants, we leave around the old
1086 // global for the moment; we'll replace all references to it
1087 // with the new global later. (See base::trans_crate.)
1088 ccx.statics_to_rauw().borrow_mut().push((g, new_g));
1091 llvm::LLVMSetAlignment(g, type_of::align_of(ccx, ty));
1092 llvm::LLVMSetInitializer(g, v);
1094 // As an optimization, all shared statics which do not have interior
1095 // mutability are placed into read-only memory.
1096 if m != hir::MutMutable {
1097 let tcontents = ty.type_contents(ccx.tcx());
1098 if !tcontents.interior_unsafe() {
1099 llvm::LLVMSetGlobalConstant(g, llvm::True);
1103 debuginfo::create_global_var_metadata(ccx, id, g);
1105 if attr::contains_name(attrs,
1107 llvm::set_thread_local(g, true);