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::const_eval::{self, ConstVal};
18 use middle::const_eval::{const_int_checked_neg, const_uint_checked_neg};
19 use middle::const_eval::{const_int_checked_add, const_uint_checked_add};
20 use middle::const_eval::{const_int_checked_sub, const_uint_checked_sub};
21 use middle::const_eval::{const_int_checked_mul, const_uint_checked_mul};
22 use middle::const_eval::{const_int_checked_div, const_uint_checked_div};
23 use middle::const_eval::{const_int_checked_rem, const_uint_checked_rem};
24 use middle::const_eval::{const_int_checked_shl, const_uint_checked_shl};
25 use middle::const_eval::{const_int_checked_shr, const_uint_checked_shr};
26 use middle::const_eval::EvalHint::ExprTypeChecked;
27 use middle::const_eval::eval_const_expr_partial;
28 use middle::def_id::{DefId, LOCAL_CRATE};
29 use trans::{adt, closure, debuginfo, expr, inline, machine};
30 use trans::base::{self, push_ctxt};
33 use trans::monomorphize;
34 use trans::type_::Type;
36 use middle::cast::{CastTy,IntTy};
37 use middle::subst::Substs;
38 use middle::ty::{self, Ty};
39 use util::nodemap::NodeMap;
41 use std::ffi::{CStr, CString};
43 use syntax::{ast, attr};
44 use syntax::parse::token;
47 pub type FnArgMap<'a> = Option<&'a NodeMap<ValueRef>>;
49 pub fn const_lit(cx: &CrateContext, e: &ast::Expr, lit: &ast::Lit)
51 let _icx = push_ctxt("trans_lit");
52 debug!("const_lit: {:?}", lit);
54 ast::LitByte(b) => C_integral(Type::uint_from_ty(cx, ast::TyU8), b as u64, false),
55 ast::LitChar(i) => C_integral(Type::char(cx), i as u64, false),
56 ast::LitInt(i, ast::SignedIntLit(t, _)) => {
57 C_integral(Type::int_from_ty(cx, t), i, true)
59 ast::LitInt(u, ast::UnsignedIntLit(t)) => {
60 C_integral(Type::uint_from_ty(cx, t), u, false)
62 ast::LitInt(i, ast::UnsuffixedIntLit(_)) => {
63 let lit_int_ty = cx.tcx().node_id_to_type(e.id);
64 match lit_int_ty.sty {
66 C_integral(Type::int_from_ty(cx, t), i as u64, true)
69 C_integral(Type::uint_from_ty(cx, t), i as u64, false)
71 _ => cx.sess().span_bug(lit.span,
72 &format!("integer literal has type {:?} (expected int \
77 ast::LitFloat(ref fs, t) => {
78 C_floating(&fs, Type::float_from_ty(cx, t))
80 ast::LitFloatUnsuffixed(ref fs) => {
81 let lit_float_ty = cx.tcx().node_id_to_type(e.id);
82 match lit_float_ty.sty {
84 C_floating(&fs, Type::float_from_ty(cx, t))
87 cx.sess().span_bug(lit.span,
88 "floating point literal doesn't have the right type");
92 ast::LitBool(b) => C_bool(cx, b),
93 ast::LitStr(ref s, _) => C_str_slice(cx, (*s).clone()),
94 ast::LitBinary(ref data) => {
95 addr_of(cx, C_bytes(cx, &data[..]), "binary")
100 pub fn ptrcast(val: ValueRef, ty: Type) -> ValueRef {
102 llvm::LLVMConstPointerCast(val, ty.to_ref())
106 fn addr_of_mut(ccx: &CrateContext,
111 // FIXME: this totally needs a better name generation scheme, perhaps a simple global
112 // counter? Also most other uses of gensym in trans.
113 let gsym = token::gensym("_");
114 let name = format!("{}{}", kind, gsym.usize());
115 let gv = declare::define_global(ccx, &name[..], val_ty(cv)).unwrap_or_else(||{
116 ccx.sess().bug(&format!("symbol `{}` is already defined", name));
118 llvm::LLVMSetInitializer(gv, cv);
119 SetLinkage(gv, InternalLinkage);
120 SetUnnamedAddr(gv, true);
125 pub fn addr_of(ccx: &CrateContext,
129 match ccx.const_globals().borrow().get(&cv) {
130 Some(&gv) => return gv,
133 let gv = addr_of_mut(ccx, cv, kind);
135 llvm::LLVMSetGlobalConstant(gv, True);
137 ccx.const_globals().borrow_mut().insert(cv, gv);
141 fn const_deref_ptr(cx: &CrateContext, v: ValueRef) -> ValueRef {
142 let v = match cx.const_unsized().borrow().get(&v) {
147 llvm::LLVMGetInitializer(v)
151 fn const_deref<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
154 -> (ValueRef, Ty<'tcx>) {
155 match ty.builtin_deref(true) {
157 if type_is_sized(cx.tcx(), mt.ty) {
158 (const_deref_ptr(cx, v), mt.ty)
160 // Derefing a fat pointer does not change the representation,
161 // just the type to the unsized contents.
166 cx.sess().bug(&format!("unexpected dereferenceable type {:?}",
172 fn const_fn_call<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
173 node: ExprOrMethodCall,
175 arg_vals: &[ValueRef],
176 param_substs: &'tcx Substs<'tcx>) -> ValueRef {
177 let fn_like = const_eval::lookup_const_fn_by_id(ccx.tcx(), def_id);
178 let fn_like = fn_like.expect("lookup_const_fn_by_id failed in const_fn_call");
180 let args = &fn_like.decl().inputs;
181 assert_eq!(args.len(), arg_vals.len());
183 let arg_ids = args.iter().map(|arg| arg.pat.id);
184 let fn_args = arg_ids.zip(arg_vals.iter().cloned()).collect();
186 let substs = ccx.tcx().mk_substs(node_id_substs(ccx, node, param_substs));
187 match fn_like.body().expr {
189 const_expr(ccx, &**expr, substs, Some(&fn_args)).0
195 pub fn get_const_expr<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
197 ref_expr: &ast::Expr)
199 let def_id = inline::maybe_instantiate_inline(ccx, def_id);
201 if def_id.krate != LOCAL_CRATE {
202 ccx.sess().span_bug(ref_expr.span,
203 "cross crate constant could not be inlined");
206 match const_eval::lookup_const_by_id(ccx.tcx(), def_id, Some(ref_expr.id)) {
207 Some(ref expr) => expr,
209 ccx.sess().span_bug(ref_expr.span, "constant item not found")
214 fn get_const_val(ccx: &CrateContext,
216 ref_expr: &ast::Expr) -> ValueRef {
217 let expr = get_const_expr(ccx, def_id, ref_expr);
218 let empty_substs = ccx.tcx().mk_substs(Substs::trans_empty());
219 get_const_expr_as_global(ccx, expr, check_const::ConstQualif::empty(), empty_substs)
222 pub fn get_const_expr_as_global<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
224 qualif: check_const::ConstQualif,
225 param_substs: &'tcx Substs<'tcx>)
227 debug!("get_const_expr_as_global: {:?}", expr.id);
228 // Special-case constants to cache a common global for all uses.
230 ast::ExprPath(..) => {
231 let def = ccx.tcx().def_map.borrow().get(&expr.id).unwrap().full_def();
233 def::DefConst(def_id) | def::DefAssociatedConst(def_id) => {
234 if !ccx.tcx().tables.borrow().adjustments.contains_key(&expr.id) {
235 debug!("get_const_expr_as_global ({:?}): found const {:?}",
237 return get_const_val(ccx, def_id, expr);
246 let key = (expr.id, param_substs);
247 match ccx.const_values().borrow().get(&key) {
248 Some(&val) => return val,
251 let val = if qualif.intersects(check_const::ConstQualif::NON_STATIC_BORROWS) {
252 // Avoid autorefs as they would create global instead of stack
253 // references, even when only the latter are correct.
254 let ty = monomorphize::apply_param_substs(ccx.tcx(), param_substs,
255 &ccx.tcx().expr_ty(expr));
256 const_expr_unadjusted(ccx, expr, ty, param_substs, None)
258 const_expr(ccx, expr, param_substs, None).0
261 // boolean SSA values are i1, but they have to be stored in i8 slots,
262 // otherwise some LLVM optimization passes don't work as expected
264 if llvm::LLVMTypeOf(val) == Type::i1(ccx).to_ref() {
265 llvm::LLVMConstZExt(val, Type::i8(ccx).to_ref())
271 let lvalue = addr_of(ccx, val, "const");
272 ccx.const_values().borrow_mut().insert(key, lvalue);
276 pub fn const_expr<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
278 param_substs: &'tcx Substs<'tcx>,
280 -> (ValueRef, Ty<'tcx>) {
281 let ety = monomorphize::apply_param_substs(cx.tcx(), param_substs,
282 &cx.tcx().expr_ty(e));
283 let llconst = const_expr_unadjusted(cx, e, ety, param_substs, fn_args);
284 let mut llconst = llconst;
285 let mut ety_adjusted = monomorphize::apply_param_substs(cx.tcx(), param_substs,
286 &cx.tcx().expr_ty_adjusted(e));
287 let opt_adj = cx.tcx().tables.borrow().adjustments.get(&e.id).cloned();
289 Some(ty::AdjustReifyFnPointer) => {
290 // FIXME(#19925) once fn item types are
291 // zero-sized, we'll need to do something here
293 Some(ty::AdjustUnsafeFnPointer) => {
294 // purely a type-level thing
296 Some(ty::AdjustDerefRef(adj)) => {
298 // Save the last autoderef in case we can avoid it.
299 if adj.autoderefs > 0 {
300 for _ in 0..adj.autoderefs-1 {
301 let (dv, dt) = const_deref(cx, llconst, ty);
307 if adj.autoref.is_some() {
308 if adj.autoderefs == 0 {
309 // Don't copy data to do a deref+ref
310 // (i.e., skip the last auto-deref).
311 llconst = addr_of(cx, llconst, "autoref");
312 ty = cx.tcx().mk_imm_ref(cx.tcx().mk_region(ty::ReStatic), ty);
315 let (dv, dt) = const_deref(cx, llconst, ty);
318 // If we derefed a fat pointer then we will have an
319 // open type here. So we need to update the type with
320 // the one returned from const_deref.
324 if let Some(target) = adj.unsize {
325 let target = monomorphize::apply_param_substs(cx.tcx(),
329 let pointee_ty = ty.builtin_deref(true)
330 .expect("consts: unsizing got non-pointer type").ty;
331 let (base, old_info) = if !type_is_sized(cx.tcx(), pointee_ty) {
332 // Normally, the source is a thin pointer and we are
333 // adding extra info to make a fat pointer. The exception
334 // is when we are upcasting an existing object fat pointer
335 // to use a different vtable. In that case, we want to
336 // load out the original data pointer so we can repackage
338 (const_get_elt(cx, llconst, &[abi::FAT_PTR_ADDR as u32]),
339 Some(const_get_elt(cx, llconst, &[abi::FAT_PTR_EXTRA as u32])))
344 let unsized_ty = target.builtin_deref(true)
345 .expect("consts: unsizing got non-pointer target type").ty;
346 let ptr_ty = type_of::in_memory_type_of(cx, unsized_ty).ptr_to();
347 let base = ptrcast(base, ptr_ty);
348 let info = expr::unsized_info(cx, pointee_ty, unsized_ty,
349 old_info, param_substs);
351 if old_info.is_none() {
352 let prev_const = cx.const_unsized().borrow_mut()
353 .insert(base, llconst);
354 assert!(prev_const.is_none() || prev_const == Some(llconst));
356 assert_eq!(abi::FAT_PTR_ADDR, 0);
357 assert_eq!(abi::FAT_PTR_EXTRA, 1);
358 llconst = C_struct(cx, &[base, info], false);
364 let llty = type_of::sizing_type_of(cx, ety_adjusted);
365 let csize = machine::llsize_of_alloc(cx, val_ty(llconst));
366 let tsize = machine::llsize_of_alloc(cx, llty);
368 cx.sess().abort_if_errors();
370 // FIXME these values could use some context
371 llvm::LLVMDumpValue(llconst);
372 llvm::LLVMDumpValue(C_undef(llty));
374 cx.sess().bug(&format!("const {:?} of type {:?} has size {} instead of {}",
378 (llconst, ety_adjusted)
381 fn check_unary_expr_validity(cx: &CrateContext, e: &ast::Expr, t: Ty,
383 // The only kind of unary expression that we check for validity
384 // here is `-expr`, to check if it "overflows" (e.g. `-i32::MIN`).
385 if let ast::ExprUnary(ast::UnNeg, ref inner_e) = e.node {
387 // An unfortunate special case: we parse e.g. -128 as a
388 // negation of the literal 128, which means if we're expecting
389 // a i8 (or if it was already suffixed, e.g. `-128_i8`), then
390 // 128 will have already overflowed to -128, and so then the
391 // constant evaluator thinks we're trying to negate -128.
393 // Catch this up front by looking for ExprLit directly,
394 // and just accepting it.
395 if let ast::ExprLit(_) = inner_e.node { return; }
397 let result = match t.sty {
398 ty::TyInt(int_type) => {
399 let input = match const_to_opt_int(te) {
403 const_int_checked_neg(
404 input, e, Some(const_eval::IntTy::from(cx.tcx(), int_type)))
406 ty::TyUint(uint_type) => {
407 let input = match const_to_opt_uint(te) {
411 const_uint_checked_neg(
412 input, e, Some(const_eval::UintTy::from(cx.tcx(), uint_type)))
417 // We do not actually care about a successful result.
418 if let Err(err) = result {
419 cx.tcx().sess.span_err(e.span, &err.description());
424 fn check_binary_expr_validity(cx: &CrateContext, e: &ast::Expr, t: Ty,
425 te1: ValueRef, te2: ValueRef) {
426 let b = if let ast::ExprBinary(b, _, _) = e.node { b } else { return };
428 let result = match t.sty {
429 ty::TyInt(int_type) => {
430 let (lhs, rhs) = match (const_to_opt_int(te1),
431 const_to_opt_int(te2)) {
432 (Some(v1), Some(v2)) => (v1, v2),
436 let opt_ety = Some(const_eval::IntTy::from(cx.tcx(), int_type));
438 ast::BiAdd => const_int_checked_add(lhs, rhs, e, opt_ety),
439 ast::BiSub => const_int_checked_sub(lhs, rhs, e, opt_ety),
440 ast::BiMul => const_int_checked_mul(lhs, rhs, e, opt_ety),
441 ast::BiDiv => const_int_checked_div(lhs, rhs, e, opt_ety),
442 ast::BiRem => const_int_checked_rem(lhs, rhs, e, opt_ety),
443 ast::BiShl => const_int_checked_shl(lhs, rhs, e, opt_ety),
444 ast::BiShr => const_int_checked_shr(lhs, rhs, e, opt_ety),
448 ty::TyUint(uint_type) => {
449 let (lhs, rhs) = match (const_to_opt_uint(te1),
450 const_to_opt_uint(te2)) {
451 (Some(v1), Some(v2)) => (v1, v2),
455 let opt_ety = Some(const_eval::UintTy::from(cx.tcx(), uint_type));
457 ast::BiAdd => const_uint_checked_add(lhs, rhs, e, opt_ety),
458 ast::BiSub => const_uint_checked_sub(lhs, rhs, e, opt_ety),
459 ast::BiMul => const_uint_checked_mul(lhs, rhs, e, opt_ety),
460 ast::BiDiv => const_uint_checked_div(lhs, rhs, e, opt_ety),
461 ast::BiRem => const_uint_checked_rem(lhs, rhs, e, opt_ety),
462 ast::BiShl => const_uint_checked_shl(lhs, rhs, e, opt_ety),
463 ast::BiShr => const_uint_checked_shr(lhs, rhs, e, opt_ety),
469 // We do not actually care about a successful result.
470 if let Err(err) = result {
471 cx.tcx().sess.span_err(e.span, &err.description());
475 fn const_expr_unadjusted<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
478 param_substs: &'tcx Substs<'tcx>,
482 debug!("const_expr_unadjusted(e={:?}, ety={:?}, param_substs={:?})",
487 let map_list = |exprs: &[P<ast::Expr>]| -> Vec<ValueRef> {
489 .map(|e| const_expr(cx, &**e, param_substs, fn_args).0)
492 let _icx = push_ctxt("const_expr");
494 ast::ExprLit(ref lit) => {
495 const_lit(cx, e, &**lit)
497 ast::ExprBinary(b, ref e1, ref e2) => {
498 /* Neither type is bottom, and we expect them to be unified
499 * already, so the following is safe. */
500 let (te1, ty) = const_expr(cx, &**e1, param_substs, fn_args);
501 debug!("const_expr_unadjusted: te1={}, ty={:?}",
502 cx.tn().val_to_string(te1),
504 assert!(!ty.is_simd());
505 let is_float = ty.is_fp();
506 let signed = ty.is_signed();
508 let (te2, _) = const_expr(cx, &**e2, param_substs, fn_args);
510 check_binary_expr_validity(cx, e, ty, te1, te2);
512 unsafe { match b.node {
513 ast::BiAdd if is_float => llvm::LLVMConstFAdd(te1, te2),
514 ast::BiAdd => llvm::LLVMConstAdd(te1, te2),
516 ast::BiSub if is_float => llvm::LLVMConstFSub(te1, te2),
517 ast::BiSub => llvm::LLVMConstSub(te1, te2),
519 ast::BiMul if is_float => llvm::LLVMConstFMul(te1, te2),
520 ast::BiMul => llvm::LLVMConstMul(te1, te2),
522 ast::BiDiv if is_float => llvm::LLVMConstFDiv(te1, te2),
523 ast::BiDiv if signed => llvm::LLVMConstSDiv(te1, te2),
524 ast::BiDiv => llvm::LLVMConstUDiv(te1, te2),
526 ast::BiRem if is_float => llvm::LLVMConstFRem(te1, te2),
527 ast::BiRem if signed => llvm::LLVMConstSRem(te1, te2),
528 ast::BiRem => llvm::LLVMConstURem(te1, te2),
530 ast::BiAnd => llvm::LLVMConstAnd(te1, te2),
531 ast::BiOr => llvm::LLVMConstOr(te1, te2),
532 ast::BiBitXor => llvm::LLVMConstXor(te1, te2),
533 ast::BiBitAnd => llvm::LLVMConstAnd(te1, te2),
534 ast::BiBitOr => llvm::LLVMConstOr(te1, te2),
536 let te2 = base::cast_shift_const_rhs(b.node, te1, te2);
537 llvm::LLVMConstShl(te1, te2)
540 let te2 = base::cast_shift_const_rhs(b.node, te1, te2);
541 if signed { llvm::LLVMConstAShr(te1, te2) }
542 else { llvm::LLVMConstLShr(te1, te2) }
544 ast::BiEq | ast::BiNe | ast::BiLt | ast::BiLe | ast::BiGt | ast::BiGe => {
546 let cmp = base::bin_op_to_fcmp_predicate(cx, b.node);
547 ConstFCmp(cmp, te1, te2)
549 let cmp = base::bin_op_to_icmp_predicate(cx, b.node, signed);
550 ConstICmp(cmp, te1, te2)
553 } } // unsafe { match b.node {
555 ast::ExprUnary(u, ref inner_e) => {
556 let (te, ty) = const_expr(cx, &**inner_e, param_substs, fn_args);
558 check_unary_expr_validity(cx, e, ty, te);
560 let is_float = ty.is_fp();
562 ast::UnUniq | ast::UnDeref => const_deref(cx, te, ty).0,
563 ast::UnNot => llvm::LLVMConstNot(te),
564 ast::UnNeg if is_float => llvm::LLVMConstFNeg(te),
565 ast::UnNeg => llvm::LLVMConstNeg(te),
568 ast::ExprField(ref base, field) => {
569 let (bv, bt) = const_expr(cx, &**base, param_substs, fn_args);
570 let brepr = adt::represent_type(cx, bt);
571 let vinfo = VariantInfo::from_ty(cx.tcx(), bt, None);
572 let ix = vinfo.field_index(field.node.name);
573 adt::const_get_field(cx, &*brepr, bv, vinfo.discr, ix)
575 ast::ExprTupField(ref base, idx) => {
576 let (bv, bt) = const_expr(cx, &**base, param_substs, fn_args);
577 let brepr = adt::represent_type(cx, bt);
578 let vinfo = VariantInfo::from_ty(cx.tcx(), bt, None);
579 adt::const_get_field(cx, &*brepr, bv, vinfo.discr, idx.node)
582 ast::ExprIndex(ref base, ref index) => {
583 let (bv, bt) = const_expr(cx, &**base, param_substs, fn_args);
584 let iv = match eval_const_expr_partial(cx.tcx(), &index, ExprTypeChecked) {
585 Ok(ConstVal::Int(i)) => i as u64,
586 Ok(ConstVal::Uint(u)) => u,
587 _ => cx.sess().span_bug(index.span,
588 "index is not an integer-constant expression")
590 let (arr, len) = match bt.sty {
591 ty::TyArray(_, u) => (bv, C_uint(cx, u)),
592 ty::TySlice(_) | ty::TyStr => {
593 let e1 = const_get_elt(cx, bv, &[0]);
594 (const_deref_ptr(cx, e1), const_get_elt(cx, bv, &[1]))
596 ty::TyRef(_, mt) => match mt.ty.sty {
597 ty::TyArray(_, u) => {
598 (const_deref_ptr(cx, bv), C_uint(cx, u))
600 _ => cx.sess().span_bug(base.span,
601 &format!("index-expr base must be a vector \
602 or string type, found {:?}",
605 _ => cx.sess().span_bug(base.span,
606 &format!("index-expr base must be a vector \
607 or string type, found {:?}",
611 let len = unsafe { llvm::LLVMConstIntGetZExtValue(len) as u64 };
612 let len = match bt.sty {
613 ty::TyBox(ty) | ty::TyRef(_, ty::TypeAndMut{ty, ..}) => match ty.sty {
623 // FIXME #3170: report this earlier on in the const-eval
624 // pass. Reporting here is a bit late.
625 cx.sess().span_err(e.span,
626 "const index-expr is out of bounds");
627 C_undef(type_of::type_of(cx, bt).element_type())
629 const_get_elt(cx, arr, &[iv as c_uint])
632 ast::ExprCast(ref base, _) => {
634 let llty = type_of::type_of(cx, t_cast);
635 let (v, t_expr) = const_expr(cx, &**base, param_substs, fn_args);
636 debug!("trans_const_cast({:?} as {:?})", t_expr, t_cast);
637 if expr::cast_is_noop(cx.tcx(), base, t_expr, t_cast) {
640 if type_is_fat_ptr(cx.tcx(), t_expr) {
641 // Fat pointer casts.
642 let t_cast_inner = t_cast.builtin_deref(true).expect("cast to non-pointer").ty;
643 let ptr_ty = type_of::in_memory_type_of(cx, t_cast_inner).ptr_to();
644 let addr = ptrcast(const_get_elt(cx, v, &[abi::FAT_PTR_ADDR as u32]),
646 if type_is_fat_ptr(cx.tcx(), t_cast) {
647 let info = const_get_elt(cx, v, &[abi::FAT_PTR_EXTRA as u32]);
648 return C_struct(cx, &[addr, info], false)
654 CastTy::from_ty(t_expr).expect("bad input type for cast"),
655 CastTy::from_ty(t_cast).expect("bad output type for cast"),
657 (CastTy::Int(IntTy::CEnum), CastTy::Int(_)) => {
658 let repr = adt::represent_type(cx, t_expr);
659 let discr = adt::const_get_discrim(cx, &*repr, v);
660 let iv = C_integral(cx.int_type(), discr, false);
661 let s = adt::is_discr_signed(&*repr) as Bool;
662 llvm::LLVMConstIntCast(iv, llty.to_ref(), s)
664 (CastTy::Int(_), CastTy::Int(_)) => {
665 let s = t_expr.is_signed() as Bool;
666 llvm::LLVMConstIntCast(v, llty.to_ref(), s)
668 (CastTy::Int(_), CastTy::Float) => {
669 if t_expr.is_signed() {
670 llvm::LLVMConstSIToFP(v, llty.to_ref())
672 llvm::LLVMConstUIToFP(v, llty.to_ref())
675 (CastTy::Float, CastTy::Float) => llvm::LLVMConstFPCast(v, llty.to_ref()),
676 (CastTy::Float, CastTy::Int(IntTy::I)) => llvm::LLVMConstFPToSI(v, llty.to_ref()),
677 (CastTy::Float, CastTy::Int(_)) => llvm::LLVMConstFPToUI(v, llty.to_ref()),
678 (CastTy::Ptr(_), CastTy::Ptr(_)) | (CastTy::FnPtr, CastTy::Ptr(_))
679 | (CastTy::RPtr(_), CastTy::Ptr(_)) => {
682 (CastTy::FnPtr, CastTy::FnPtr) => ptrcast(v, llty), // isn't this a coercion?
683 (CastTy::Int(_), CastTy::Ptr(_)) => llvm::LLVMConstIntToPtr(v, llty.to_ref()),
684 (CastTy::Ptr(_), CastTy::Int(_)) | (CastTy::FnPtr, CastTy::Int(_)) => {
685 llvm::LLVMConstPtrToInt(v, llty.to_ref())
688 cx.sess().impossible_case(e.span,
689 "bad combination of types for cast")
691 } } // unsafe { match ( ... ) {
693 ast::ExprAddrOf(ast::MutImmutable, ref sub) => {
694 // If this is the address of some static, then we need to return
695 // the actual address of the static itself (short circuit the rest
700 ast::ExprParen(ref sub) => cur = sub,
701 ast::ExprBlock(ref blk) => {
702 if let Some(ref sub) = blk.expr {
711 let opt_def = cx.tcx().def_map.borrow().get(&cur.id).map(|d| d.full_def());
712 if let Some(def::DefStatic(def_id, _)) = opt_def {
713 get_static_val(cx, def_id, ety)
715 // If this isn't the address of a static, then keep going through
716 // normal constant evaluation.
717 let (v, _) = const_expr(cx, &**sub, param_substs, fn_args);
718 addr_of(cx, v, "ref")
721 ast::ExprAddrOf(ast::MutMutable, ref sub) => {
722 let (v, _) = const_expr(cx, &**sub, param_substs, fn_args);
723 addr_of_mut(cx, v, "ref_mut_slice")
725 ast::ExprTup(ref es) => {
726 let repr = adt::represent_type(cx, ety);
727 let vals = map_list(&es[..]);
728 adt::trans_const(cx, &*repr, 0, &vals[..])
730 ast::ExprStruct(_, ref fs, ref base_opt) => {
731 let repr = adt::represent_type(cx, ety);
733 let base_val = match *base_opt {
734 Some(ref base) => Some(const_expr(cx, &**base, param_substs, fn_args)),
738 let VariantInfo { discr, fields } = VariantInfo::of_node(cx.tcx(), ety, e.id);
739 let cs = fields.iter().enumerate().map(|(ix, &Field(f_name, _))| {
740 match (fs.iter().find(|f| f_name == f.ident.node.name), base_val) {
741 (Some(ref f), _) => const_expr(cx, &*f.expr, param_substs, fn_args).0,
742 (_, Some((bv, _))) => adt::const_get_field(cx, &*repr, bv, discr, ix),
743 (_, None) => cx.sess().span_bug(e.span, "missing struct field"),
745 }).collect::<Vec<_>>();
749 adt::trans_const(cx, &*repr, discr, &cs[..])
752 ast::ExprVec(ref es) => {
753 let unit_ty = ety.sequence_element_type(cx.tcx());
754 let llunitty = type_of::type_of(cx, unit_ty);
756 .map(|e| const_expr(cx, &**e, param_substs, fn_args).0)
757 .collect::<Vec<_>>();
758 // If the vector contains enums, an LLVM array won't work.
759 if vs.iter().any(|vi| val_ty(*vi) != llunitty) {
760 C_struct(cx, &vs[..], false)
762 C_array(llunitty, &vs[..])
765 ast::ExprRepeat(ref elem, ref count) => {
766 let unit_ty = ety.sequence_element_type(cx.tcx());
767 let llunitty = type_of::type_of(cx, unit_ty);
768 let n = cx.tcx().eval_repeat_count(count);
769 let unit_val = const_expr(cx, &**elem, param_substs, fn_args).0;
770 let vs = vec![unit_val; n];
771 if val_ty(unit_val) != llunitty {
772 C_struct(cx, &vs[..], false)
774 C_array(llunitty, &vs[..])
777 ast::ExprPath(..) => {
778 let def = cx.tcx().def_map.borrow().get(&e.id).unwrap().full_def();
780 def::DefLocal(id) => {
781 if let Some(val) = fn_args.and_then(|args| args.get(&id).cloned()) {
784 cx.sess().span_bug(e.span, "const fn argument not found")
787 def::DefFn(..) | def::DefMethod(..) => {
788 expr::trans_def_fn_unadjusted(cx, e, def, param_substs).val
790 def::DefConst(def_id) | def::DefAssociatedConst(def_id) => {
791 const_deref_ptr(cx, get_const_val(cx, def_id, e))
793 def::DefVariant(enum_did, variant_did, _) => {
794 let vinfo = cx.tcx().lookup_adt_def(enum_did).variant_with_id(variant_did);
796 ty::VariantKind::Unit => {
797 let repr = adt::represent_type(cx, ety);
798 adt::trans_const(cx, &*repr, vinfo.disr_val, &[])
800 ty::VariantKind::Tuple => {
801 expr::trans_def_fn_unadjusted(cx, e, def, param_substs).val
803 ty::VariantKind::Dict => {
804 cx.sess().span_bug(e.span, "path-expr refers to a dict variant!")
808 def::DefStruct(_) => {
809 if let ty::TyBareFn(..) = ety.sty {
811 expr::trans_def_fn_unadjusted(cx, e, def, param_substs).val
814 C_null(type_of::type_of(cx, ety))
818 cx.sess().span_bug(e.span, "expected a const, fn, struct, \
823 ast::ExprCall(ref callee, ref args) => {
824 let mut callee = &**callee;
826 callee = match callee.node {
827 ast::ExprParen(ref inner) => &**inner,
828 ast::ExprBlock(ref block) => match block.expr {
829 Some(ref tail) => &**tail,
835 let def = cx.tcx().def_map.borrow()[&callee.id].full_def();
836 let arg_vals = map_list(args);
838 def::DefFn(did, _) | def::DefMethod(did) => {
839 const_fn_call(cx, ExprId(callee.id), did, &arg_vals, param_substs)
841 def::DefStruct(_) => {
843 C_vector(&arg_vals[..])
845 let repr = adt::represent_type(cx, ety);
846 adt::trans_const(cx, &*repr, 0, &arg_vals[..])
849 def::DefVariant(enum_did, variant_did, _) => {
850 let repr = adt::represent_type(cx, ety);
851 let vinfo = cx.tcx().lookup_adt_def(enum_did).variant_with_id(variant_did);
857 _ => cx.sess().span_bug(e.span, "expected a struct, variant, or const fn def"),
860 ast::ExprMethodCall(_, _, ref args) => {
861 let arg_vals = map_list(args);
862 let method_call = ty::MethodCall::expr(e.id);
863 let method_did = cx.tcx().tables.borrow().method_map[&method_call].def_id;
864 const_fn_call(cx, MethodCallKey(method_call),
865 method_did, &arg_vals, param_substs)
867 ast::ExprParen(ref e) => const_expr(cx, &**e, param_substs, fn_args).0,
868 ast::ExprBlock(ref block) => {
870 Some(ref expr) => const_expr(cx, &**expr, param_substs, fn_args).0,
874 ast::ExprClosure(_, ref decl, ref body) => {
876 ty::TyClosure(_, ref substs) => {
877 closure::trans_closure_expr(closure::Dest::Ignore(cx), decl,
883 &format!("bad type for closure expr: {:?}", ety))
885 C_null(type_of::type_of(cx, ety))
887 _ => cx.sess().span_bug(e.span,
888 "bad constant expression type in consts::const_expr"),
891 pub fn trans_static(ccx: &CrateContext,
895 attrs: &Vec<ast::Attribute>)
898 let _icx = push_ctxt("trans_static");
899 let g = base::get_item_val(ccx, id);
901 let empty_substs = ccx.tcx().mk_substs(Substs::trans_empty());
902 let (v, _) = const_expr(ccx, expr, empty_substs, None);
904 // boolean SSA values are i1, but they have to be stored in i8 slots,
905 // otherwise some LLVM optimization passes don't work as expected
906 let mut val_llty = llvm::LLVMTypeOf(v);
907 let v = if val_llty == Type::i1(ccx).to_ref() {
908 val_llty = Type::i8(ccx).to_ref();
909 llvm::LLVMConstZExt(v, val_llty)
914 let ty = ccx.tcx().node_id_to_type(id);
915 let llty = type_of::type_of(ccx, ty);
916 let g = if val_llty == llty.to_ref() {
919 // If we created the global with the wrong type,
921 let empty_string = CString::new("").unwrap();
922 let name_str_ref = CStr::from_ptr(llvm::LLVMGetValueName(g));
923 let name_string = CString::new(name_str_ref.to_bytes()).unwrap();
924 llvm::LLVMSetValueName(g, empty_string.as_ptr());
925 let new_g = llvm::LLVMGetOrInsertGlobal(
926 ccx.llmod(), name_string.as_ptr(), val_llty);
927 // To avoid breaking any invariants, we leave around the old
928 // global for the moment; we'll replace all references to it
929 // with the new global later. (See base::trans_crate.)
930 ccx.statics_to_rauw().borrow_mut().push((g, new_g));
933 llvm::LLVMSetInitializer(g, v);
935 // As an optimization, all shared statics which do not have interior
936 // mutability are placed into read-only memory.
937 if m != ast::MutMutable {
938 let tcontents = ty.type_contents(ccx.tcx());
939 if !tcontents.interior_unsafe() {
940 llvm::LLVMSetGlobalConstant(g, llvm::True);
944 debuginfo::create_global_var_metadata(ccx, id, g);
946 if attr::contains_name(attrs,
948 llvm::set_thread_local(g, true);
955 fn get_static_val<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
959 if did.is_local() { return base::get_item_val(ccx, did.node) }
960 base::trans_external_path(ccx, did, ty)