1 // Copyright 2012-2014 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.
11 #![allow(non_camel_case_types)]
13 //! Code that is useful in various trans modules.
15 use driver::session::Session;
16 use lib::llvm::{ValueRef, BasicBlockRef, BuilderRef};
17 use lib::llvm::{True, False, Bool};
20 use middle::lang_items::LangItem;
21 use middle::trans::build;
22 use middle::trans::cleanup;
23 use middle::trans::datum;
24 use middle::trans::datum::{Datum, Lvalue};
25 use middle::trans::debuginfo;
26 use middle::trans::type_::Type;
28 use middle::subst::Subst;
30 use util::ppaux::Repr;
31 use util::nodemap::NodeMap;
33 use arena::TypedArena;
34 use collections::HashMap;
35 use libc::{c_uint, c_longlong, c_ulonglong, c_char};
36 use std::c_str::ToCStr;
37 use std::cell::{Cell, RefCell};
39 use syntax::ast::Ident;
41 use syntax::ast_map::{PathElem, PathName};
42 use syntax::codemap::Span;
43 use syntax::parse::token::InternedString;
44 use syntax::parse::token;
46 pub use middle::trans::context::CrateContext;
48 fn type_is_newtype_immediate(ccx: &CrateContext, ty: ty::t) -> bool {
49 match ty::get(ty).sty {
50 ty::ty_struct(def_id, ref substs) => {
51 let fields = ty::struct_fields(ccx.tcx(), def_id, substs);
53 fields.get(0).ident.name ==
54 token::special_idents::unnamed_field.name &&
55 type_is_immediate(ccx, fields.get(0).mt.ty)
61 pub fn type_is_immediate(ccx: &CrateContext, ty: ty::t) -> bool {
62 use middle::trans::machine::llsize_of_alloc;
63 use middle::trans::type_of::sizing_type_of;
65 let simple = ty::type_is_scalar(ty) || ty::type_is_boxed(ty) ||
66 ty::type_is_unique(ty) || ty::type_is_region_ptr(ty) ||
67 type_is_newtype_immediate(ccx, ty) || ty::type_is_bot(ty) ||
68 ty::type_is_simd(tcx, ty);
72 match ty::get(ty).sty {
74 ty::ty_struct(..) | ty::ty_enum(..) | ty::ty_tup(..) => {
75 let llty = sizing_type_of(ccx, ty);
76 llsize_of_alloc(ccx, llty) <= llsize_of_alloc(ccx, ccx.int_type)
78 _ => type_is_zero_size(ccx, ty)
82 pub fn type_is_zero_size(ccx: &CrateContext, ty: ty::t) -> bool {
84 * Identify types which have size zero at runtime.
87 use middle::trans::machine::llsize_of_alloc;
88 use middle::trans::type_of::sizing_type_of;
89 let llty = sizing_type_of(ccx, ty);
90 llsize_of_alloc(ccx, llty) == 0
93 pub fn return_type_is_void(ccx: &CrateContext, ty: ty::t) -> bool {
95 * Identifies types which we declare to be equivalent to `void`
96 * in C for the purpose of function return types. These are
97 * `()`, bot, and uninhabited enums. Note that all such types
98 * are also zero-size, but not all zero-size types use a `void`
99 * return type (in order to aid with C ABI compatibility).
102 ty::type_is_nil(ty) || ty::type_is_bot(ty) || ty::type_is_empty(ccx.tcx(), ty)
105 /// Generates a unique symbol based off the name given. This is used to create
106 /// unique symbols for things like closures.
107 pub fn gensym_name(name: &str) -> PathElem {
108 let num = token::gensym(name);
109 // use one colon which will get translated to a period by the mangler, and
110 // we're guaranteed that `num` is globally unique for this crate.
111 PathName(token::gensym(format!("{}:{}", name, num).as_slice()))
114 pub struct tydesc_info {
116 pub tydesc: ValueRef,
120 pub visit_glue: Cell<Option<ValueRef>>,
124 * A note on nomenclature of linking: "extern", "foreign", and "upcall".
126 * An "extern" is an LLVM symbol we wind up emitting an undefined external
127 * reference to. This means "we don't have the thing in this compilation unit,
128 * please make sure you link it in at runtime". This could be a reference to
129 * C code found in a C library, or rust code found in a rust crate.
131 * Most "externs" are implicitly declared (automatically) as a result of a
132 * user declaring an extern _module_ dependency; this causes the rust driver
133 * to locate an extern crate, scan its compilation metadata, and emit extern
134 * declarations for any symbols used by the declaring crate.
136 * A "foreign" is an extern that references C (or other non-rust ABI) code.
137 * There is no metadata to scan for extern references so in these cases either
138 * a header-digester like bindgen, or manual function prototypes, have to
139 * serve as declarators. So these are usually given explicitly as prototype
140 * declarations, in rust code, with ABI attributes on them noting which ABI to
143 * An "upcall" is a foreign call generated by the compiler (not corresponding
144 * to any user-written call in the code) into the runtime library, to perform
145 * some helper task such as bringing a task to life, allocating memory, etc.
149 pub struct NodeInfo {
154 pub fn expr_info(expr: &ast::Expr) -> NodeInfo {
155 NodeInfo { id: expr.id, span: expr.span }
158 pub struct BuilderRef_res {
162 impl Drop for BuilderRef_res {
165 llvm::LLVMDisposeBuilder(self.b);
170 pub fn BuilderRef_res(b: BuilderRef) -> BuilderRef_res {
176 pub type ExternMap = HashMap<String, ValueRef>;
178 // Here `self_ty` is the real type of the self parameter to this method. It
179 // will only be set in the case of default methods.
180 pub struct param_substs {
181 pub substs: ty::substs,
182 pub vtables: Option<typeck::vtable_res>,
183 pub self_vtables: Option<typeck::vtable_param_res>
187 pub fn validate(&self) {
188 for t in self.substs.tps.iter() {
189 assert!(!ty::type_needs_infer(*t));
191 for t in self.substs.self_ty.iter() {
192 assert!(!ty::type_needs_infer(*t));
197 fn param_substs_to_str(this: ¶m_substs, tcx: &ty::ctxt) -> String {
198 format_strbuf!("param_substs({})", this.substs.repr(tcx))
201 impl Repr for param_substs {
202 fn repr(&self, tcx: &ty::ctxt) -> String {
203 param_substs_to_str(self, tcx)
208 fn substp(&self, tcx: &ty::ctxt, param_substs: Option<¶m_substs>)
212 impl<T:Subst+Clone> SubstP for T {
213 fn substp(&self, tcx: &ty::ctxt, param_substs: Option<¶m_substs>)
217 self.subst(tcx, &substs.substs)
226 // work around bizarre resolve errors
227 pub type RvalueDatum = datum::Datum<datum::Rvalue>;
228 pub type LvalueDatum = datum::Datum<datum::Lvalue>;
230 // Function context. Every LLVM function we create will have one of
232 pub struct FunctionContext<'a> {
233 // The ValueRef returned from a call to llvm::LLVMAddFunction; the
234 // address of the first instruction in the sequence of
235 // instructions for this function that will go in the .text
236 // section of the executable we're generating.
239 // The environment argument in a closure.
240 pub llenv: Option<ValueRef>,
242 // The place to store the return value. If the return type is immediate,
243 // this is an alloca in the function. Otherwise, it's the hidden first
244 // parameter to the function. After function construction, this should
246 pub llretptr: Cell<Option<ValueRef>>,
248 pub entry_bcx: RefCell<Option<&'a Block<'a>>>,
250 // These pub elements: "hoisted basic blocks" containing
251 // administrative activities that have to happen in only one place in
252 // the function, due to LLVM's quirks.
253 // A marker for the place where we want to insert the function's static
254 // allocas, so that LLVM will coalesce them into a single alloca call.
255 pub alloca_insert_pt: Cell<Option<ValueRef>>,
256 pub llreturn: Cell<Option<BasicBlockRef>>,
258 // The a value alloca'd for calls to upcalls.rust_personality. Used when
259 // outputting the resume instruction.
260 pub personality: Cell<Option<ValueRef>>,
262 // True if the caller expects this fn to use the out pointer to
263 // return. Either way, your code should write into llretptr, but if
264 // this value is false, llretptr will be a local alloca.
265 pub caller_expects_out_pointer: bool,
267 // Maps arguments to allocas created for them in llallocas.
268 pub llargs: RefCell<NodeMap<LvalueDatum>>,
270 // Maps the def_ids for local variables to the allocas created for
271 // them in llallocas.
272 pub lllocals: RefCell<NodeMap<LvalueDatum>>,
274 // Same as above, but for closure upvars
275 pub llupvars: RefCell<NodeMap<ValueRef>>,
277 // The NodeId of the function, or -1 if it doesn't correspond to
278 // a user-defined function.
281 // If this function is being monomorphized, this contains the type
282 // substitutions used.
283 pub param_substs: Option<&'a param_substs>,
285 // The source span and nesting context where this function comes from, for
286 // error reporting and symbol generation.
287 pub span: Option<Span>,
289 // The arena that blocks are allocated from.
290 pub block_arena: &'a TypedArena<Block<'a>>,
292 // This function's enclosing crate context.
293 pub ccx: &'a CrateContext,
295 // Used and maintained by the debuginfo module.
296 pub debug_context: debuginfo::FunctionDebugContext,
299 pub scopes: RefCell<Vec<cleanup::CleanupScope<'a>> >,
302 impl<'a> FunctionContext<'a> {
303 pub fn arg_pos(&self, arg: uint) -> uint {
304 let arg = self.env_arg_pos() + arg;
305 if self.llenv.is_some() {
312 pub fn out_arg_pos(&self) -> uint {
313 assert!(self.caller_expects_out_pointer);
317 pub fn env_arg_pos(&self) -> uint {
318 if self.caller_expects_out_pointer {
325 pub fn cleanup(&self) {
327 llvm::LLVMInstructionEraseFromParent(self.alloca_insert_pt
331 // Remove the cycle between fcx and bcx, so memory can be freed
332 *self.entry_bcx.borrow_mut() = None;
335 pub fn get_llreturn(&self) -> BasicBlockRef {
336 if self.llreturn.get().is_none() {
338 self.llreturn.set(Some(unsafe {
339 "return".with_c_str(|buf| {
340 llvm::LLVMAppendBasicBlockInContext(self.ccx.llcx, self.llfn, buf)
345 self.llreturn.get().unwrap()
348 pub fn new_block(&'a self,
351 opt_node_id: Option<ast::NodeId>)
354 let llbb = name.with_c_str(|buf| {
355 llvm::LLVMAppendBasicBlockInContext(self.ccx.llcx,
359 Block::new(llbb, is_lpad, opt_node_id, self)
363 pub fn new_id_block(&'a self,
365 node_id: ast::NodeId)
367 self.new_block(false, name, Some(node_id))
370 pub fn new_temp_block(&'a self,
373 self.new_block(false, name, None)
376 pub fn join_blocks(&'a self,
378 in_cxs: &[&'a Block<'a>])
380 let out = self.new_id_block("join", id);
381 let mut reachable = false;
382 for bcx in in_cxs.iter() {
383 if !bcx.unreachable.get() {
384 build::Br(*bcx, out.llbb);
389 build::Unreachable(out);
395 // Basic block context. We create a block context for each basic block
396 // (single-entry, single-exit sequence of instructions) we generate from Rust
397 // code. Each basic block we generate is attached to a function, typically
398 // with many basic blocks per function. All the basic blocks attached to a
399 // function are organized as a directed graph.
400 pub struct Block<'a> {
401 // The BasicBlockRef returned from a call to
402 // llvm::LLVMAppendBasicBlock(llfn, name), which adds a basic
403 // block to the function pointed to by llfn. We insert
404 // instructions into that block by way of this block context.
405 // The block pointing to this one in the function's digraph.
406 pub llbb: BasicBlockRef,
407 pub terminated: Cell<bool>,
408 pub unreachable: Cell<bool>,
410 // Is this block part of a landing pad?
413 // AST node-id associated with this block, if any. Used for
414 // debugging purposes only.
415 pub opt_node_id: Option<ast::NodeId>,
417 // The function context for the function to which this block is
419 pub fcx: &'a FunctionContext<'a>,
426 opt_node_id: Option<ast::NodeId>,
427 fcx: &'a FunctionContext<'a>)
429 fcx.block_arena.alloc(Block {
431 terminated: Cell::new(false),
432 unreachable: Cell::new(false),
434 opt_node_id: opt_node_id,
439 pub fn ccx(&self) -> &'a CrateContext { self.fcx.ccx }
440 pub fn tcx(&self) -> &'a ty::ctxt {
443 pub fn sess(&self) -> &'a Session { self.fcx.ccx.sess() }
445 pub fn ident(&self, ident: Ident) -> String {
446 token::get_ident(ident).get().to_string()
449 pub fn node_id_to_str(&self, id: ast::NodeId) -> String {
450 self.tcx().map.node_to_str(id).to_string()
453 pub fn expr_to_str(&self, e: &ast::Expr) -> String {
457 pub fn def(&self, nid: ast::NodeId) -> ast::Def {
458 match self.tcx().def_map.borrow().find(&nid) {
461 self.tcx().sess.bug(format!(
462 "no def associated with node id {:?}", nid).as_slice());
467 pub fn val_to_str(&self, val: ValueRef) -> String {
468 self.ccx().tn.val_to_str(val)
471 pub fn llty_str(&self, ty: Type) -> String {
472 self.ccx().tn.type_to_str(ty)
475 pub fn ty_to_str(&self, t: ty::t) -> String {
479 pub fn to_str(&self) -> String {
480 let blk: *Block = self;
481 format_strbuf!("[block {}]", blk)
485 pub struct Result<'a> {
486 pub bcx: &'a Block<'a>,
490 impl<'a> Result<'a> {
491 pub fn new(bcx: &'a Block<'a>, val: ValueRef) -> Result<'a> {
499 pub fn val_ty(v: ValueRef) -> Type {
501 Type::from_ref(llvm::LLVMTypeOf(v))
505 // LLVM constant constructors.
506 pub fn C_null(t: Type) -> ValueRef {
508 llvm::LLVMConstNull(t.to_ref())
512 pub fn C_undef(t: Type) -> ValueRef {
514 llvm::LLVMGetUndef(t.to_ref())
518 pub fn C_integral(t: Type, u: u64, sign_extend: bool) -> ValueRef {
520 llvm::LLVMConstInt(t.to_ref(), u, sign_extend as Bool)
524 pub fn C_floating(s: &str, t: Type) -> ValueRef {
526 s.with_c_str(|buf| llvm::LLVMConstRealOfString(t.to_ref(), buf))
530 pub fn C_nil(ccx: &CrateContext) -> ValueRef {
531 C_struct(ccx, [], false)
534 pub fn C_bool(ccx: &CrateContext, val: bool) -> ValueRef {
535 C_integral(Type::bool(ccx), val as u64, false)
538 pub fn C_i1(ccx: &CrateContext, val: bool) -> ValueRef {
539 C_integral(Type::i1(ccx), val as u64, false)
542 pub fn C_i32(ccx: &CrateContext, i: i32) -> ValueRef {
543 C_integral(Type::i32(ccx), i as u64, true)
546 pub fn C_i64(ccx: &CrateContext, i: i64) -> ValueRef {
547 C_integral(Type::i64(ccx), i as u64, true)
550 pub fn C_u64(ccx: &CrateContext, i: u64) -> ValueRef {
551 C_integral(Type::i64(ccx), i, false)
554 pub fn C_int(ccx: &CrateContext, i: int) -> ValueRef {
555 C_integral(ccx.int_type, i as u64, true)
558 pub fn C_uint(ccx: &CrateContext, i: uint) -> ValueRef {
559 C_integral(ccx.int_type, i as u64, false)
562 pub fn C_u8(ccx: &CrateContext, i: uint) -> ValueRef {
563 C_integral(Type::i8(ccx), i as u64, false)
567 // This is a 'c-like' raw string, which differs from
568 // our boxed-and-length-annotated strings.
569 pub fn C_cstr(cx: &CrateContext, s: InternedString, null_terminated: bool) -> ValueRef {
571 match cx.const_cstr_cache.borrow().find(&s) {
572 Some(&llval) => return llval,
576 let sc = llvm::LLVMConstStringInContext(cx.llcx,
577 s.get().as_ptr() as *c_char,
578 s.get().len() as c_uint,
579 !null_terminated as Bool);
581 let gsym = token::gensym("str");
582 let g = format!("str{}", gsym).with_c_str(|buf| {
583 llvm::LLVMAddGlobal(cx.llmod, val_ty(sc).to_ref(), buf)
585 llvm::LLVMSetInitializer(g, sc);
586 llvm::LLVMSetGlobalConstant(g, True);
587 lib::llvm::SetLinkage(g, lib::llvm::InternalLinkage);
589 cx.const_cstr_cache.borrow_mut().insert(s, g);
594 // NB: Do not use `do_spill_noroot` to make this into a constant string, or
595 // you will be kicked off fast isel. See issue #4352 for an example of this.
596 pub fn C_str_slice(cx: &CrateContext, s: InternedString) -> ValueRef {
598 let len = s.get().len();
599 let cs = llvm::LLVMConstPointerCast(C_cstr(cx, s, false),
600 Type::i8p(cx).to_ref());
601 C_struct(cx, [cs, C_uint(cx, len)], false)
605 pub fn C_binary_slice(cx: &CrateContext, data: &[u8]) -> ValueRef {
607 let len = data.len();
608 let lldata = C_bytes(cx, data);
610 let gsym = token::gensym("binary");
611 let g = format!("binary{}", gsym).with_c_str(|buf| {
612 llvm::LLVMAddGlobal(cx.llmod, val_ty(lldata).to_ref(), buf)
614 llvm::LLVMSetInitializer(g, lldata);
615 llvm::LLVMSetGlobalConstant(g, True);
616 lib::llvm::SetLinkage(g, lib::llvm::InternalLinkage);
618 let cs = llvm::LLVMConstPointerCast(g, Type::i8p(cx).to_ref());
619 C_struct(cx, [cs, C_uint(cx, len)], false)
623 pub fn C_struct(ccx: &CrateContext, elts: &[ValueRef], packed: bool) -> ValueRef {
625 llvm::LLVMConstStructInContext(ccx.llcx,
626 elts.as_ptr(), elts.len() as c_uint,
631 pub fn C_named_struct(t: Type, elts: &[ValueRef]) -> ValueRef {
633 llvm::LLVMConstNamedStruct(t.to_ref(), elts.as_ptr(), elts.len() as c_uint)
637 pub fn C_array(ty: Type, elts: &[ValueRef]) -> ValueRef {
639 return llvm::LLVMConstArray(ty.to_ref(), elts.as_ptr(), elts.len() as c_uint);
643 pub fn C_bytes(ccx: &CrateContext, bytes: &[u8]) -> ValueRef {
645 let ptr = bytes.as_ptr() as *c_char;
646 return llvm::LLVMConstStringInContext(ccx.llcx, ptr, bytes.len() as c_uint, True);
650 pub fn get_param(fndecl: ValueRef, param: uint) -> ValueRef {
652 llvm::LLVMGetParam(fndecl, param as c_uint)
656 pub fn const_get_elt(cx: &CrateContext, v: ValueRef, us: &[c_uint])
659 let r = llvm::LLVMConstExtractValue(v, us.as_ptr(), us.len() as c_uint);
661 debug!("const_get_elt(v={}, us={:?}, r={})",
662 cx.tn.val_to_str(v), us, cx.tn.val_to_str(r));
668 pub fn is_const(v: ValueRef) -> bool {
670 llvm::LLVMIsConstant(v) == True
674 pub fn const_to_int(v: ValueRef) -> c_longlong {
676 llvm::LLVMConstIntGetSExtValue(v)
680 pub fn const_to_uint(v: ValueRef) -> c_ulonglong {
682 llvm::LLVMConstIntGetZExtValue(v)
686 pub fn is_undef(val: ValueRef) -> bool {
688 llvm::LLVMIsUndef(val) != False
692 pub fn is_null(val: ValueRef) -> bool {
694 llvm::LLVMIsNull(val) != False
698 pub fn monomorphize_type(bcx: &Block, t: ty::t) -> ty::t {
699 match bcx.fcx.param_substs {
700 Some(ref substs) => {
701 ty::subst(bcx.tcx(), &substs.substs, t)
704 assert!(!ty::type_has_params(t));
705 assert!(!ty::type_has_self(t));
711 pub fn node_id_type(bcx: &Block, id: ast::NodeId) -> ty::t {
713 let t = ty::node_id_to_type(tcx, id);
714 monomorphize_type(bcx, t)
717 pub fn expr_ty(bcx: &Block, ex: &ast::Expr) -> ty::t {
718 node_id_type(bcx, ex.id)
721 pub fn expr_ty_adjusted(bcx: &Block, ex: &ast::Expr) -> ty::t {
722 monomorphize_type(bcx, ty::expr_ty_adjusted(bcx.tcx(), ex))
725 // Key used to lookup values supplied for type parameters in an expr.
727 pub enum ExprOrMethodCall {
728 // Type parameters for a path like `None::<int>`
731 // Type parameters for a method call like `a.foo::<int>()`
732 MethodCall(typeck::MethodCall)
735 pub fn node_id_substs(bcx: &Block,
736 node: ExprOrMethodCall)
740 let substs = match node {
742 ty::node_id_item_substs(tcx, id).substs
744 MethodCall(method_call) => {
745 tcx.method_map.borrow().get(&method_call).substs.clone()
749 if !substs.tps.iter().all(|t| !ty::type_needs_infer(*t)) {
751 format!("type parameters for node {:?} include inference types: \
754 substs.repr(bcx.tcx())).as_slice());
757 substs.substp(tcx, bcx.fcx.param_substs)
760 pub fn node_vtables(bcx: &Block, id: typeck::MethodCall)
761 -> Option<typeck::vtable_res> {
762 bcx.tcx().vtable_map.borrow().find(&id).map(|vts| {
763 resolve_vtables_in_fn_ctxt(bcx.fcx, vts.as_slice())
767 // Apply the typaram substitutions in the FunctionContext to some
768 // vtables. This should eliminate any vtable_params.
769 pub fn resolve_vtables_in_fn_ctxt(fcx: &FunctionContext,
770 vts: &[typeck::vtable_param_res])
771 -> typeck::vtable_res {
772 resolve_vtables_under_param_substs(fcx.ccx.tcx(),
777 pub fn resolve_vtables_under_param_substs(tcx: &ty::ctxt,
778 param_substs: Option<¶m_substs>,
779 vts: &[typeck::vtable_param_res])
780 -> typeck::vtable_res {
781 vts.iter().map(|ds| {
782 resolve_param_vtables_under_param_substs(tcx,
788 pub fn resolve_param_vtables_under_param_substs(
790 param_substs: Option<¶m_substs>,
791 ds: &[typeck::vtable_origin])
792 -> typeck::vtable_param_res {
794 resolve_vtable_under_param_substs(tcx,
802 pub fn resolve_vtable_under_param_substs(tcx: &ty::ctxt,
803 param_substs: Option<¶m_substs>,
804 vt: &typeck::vtable_origin)
805 -> typeck::vtable_origin {
807 typeck::vtable_static(trait_id, ref vtable_substs, ref sub) => {
808 let vtable_substs = vtable_substs.substp(tcx, param_substs);
809 typeck::vtable_static(
810 trait_id, vtable_substs,
811 resolve_vtables_under_param_substs(tcx, param_substs, sub.as_slice()))
813 typeck::vtable_param(n_param, n_bound) => {
816 find_vtable(tcx, substs, n_param, n_bound)
819 tcx.sess.bug(format!(
820 "resolve_vtable_under_param_substs: asked to lookup \
821 but no vtables in the fn_ctxt!").as_slice())
828 pub fn find_vtable(tcx: &ty::ctxt,
830 n_param: typeck::param_index,
832 -> typeck::vtable_origin {
833 debug!("find_vtable(n_param={:?}, n_bound={}, ps={})",
834 n_param, n_bound, ps.repr(tcx));
836 let param_bounds = match n_param {
837 typeck::param_self => ps.self_vtables.as_ref().expect("self vtables missing"),
838 typeck::param_numbered(n) => {
839 let tables = ps.vtables.as_ref()
840 .expect("vtables missing where they are needed");
844 param_bounds.get(n_bound).clone()
847 // Casts a Rust bool value to an i1.
848 pub fn bool_to_i1(bcx: &Block, llval: ValueRef) -> ValueRef {
849 build::ICmp(bcx, lib::llvm::IntNE, llval, C_bool(bcx.ccx(), false))
852 pub fn langcall(bcx: &Block,
857 match bcx.tcx().lang_items.require(li) {
860 let msg = format!("{} {}", msg, s);
862 Some(span) => bcx.tcx().sess.span_fatal(span, msg.as_slice()),
863 None => bcx.tcx().sess.fatal(msg.as_slice()),