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, non_snake_case)]
13 //! Code that is useful in various trans modules.
15 pub use self::ExprOrMethodCall::*;
19 use llvm::{ValueRef, BasicBlockRef, BuilderRef, ContextRef};
20 use llvm::{True, False, Bool};
23 use middle::def_id::DefId;
25 use middle::lang_items::LangItem;
26 use middle::subst::{self, Substs};
33 use trans::debuginfo::{self, DebugLoc};
36 use trans::monomorphize;
37 use trans::type_::Type;
40 use middle::ty::{self, HasTypeFlags, Ty};
41 use middle::ty::fold::{TypeFolder, TypeFoldable};
42 use rustc::front::map::{PathElem, PathName};
44 use util::nodemap::{FnvHashMap, NodeMap};
46 use arena::TypedArena;
47 use libc::{c_uint, c_char};
48 use std::ffi::CString;
49 use std::cell::{Cell, RefCell};
52 use syntax::codemap::{DUMMY_SP, Span};
53 use syntax::parse::token::InternedString;
54 use syntax::parse::token;
56 pub use trans::context::CrateContext;
58 /// Is the type's representation size known at compile time?
59 pub fn type_is_sized<'tcx>(tcx: &ty::ctxt<'tcx>, ty: Ty<'tcx>) -> bool {
60 ty.is_sized(&tcx.empty_parameter_environment(), DUMMY_SP)
63 pub fn type_is_fat_ptr<'tcx>(cx: &ty::ctxt<'tcx>, ty: Ty<'tcx>) -> bool {
65 ty::TyRawPtr(ty::TypeAndMut{ty, ..}) |
66 ty::TyRef(_, ty::TypeAndMut{ty, ..}) |
68 !type_is_sized(cx, ty)
76 /// If `type_needs_drop` returns true, then `ty` is definitely
77 /// non-copy and *might* have a destructor attached; if it returns
78 /// false, then `ty` definitely has no destructor (i.e. no drop glue).
80 /// (Note that this implies that if `ty` has a destructor attached,
81 /// then `type_needs_drop` will definitely return `true` for `ty`.)
82 pub fn type_needs_drop<'tcx>(cx: &ty::ctxt<'tcx>, ty: Ty<'tcx>) -> bool {
83 type_needs_drop_given_env(cx, ty, &cx.empty_parameter_environment())
86 /// Core implementation of type_needs_drop, potentially making use of
87 /// and/or updating caches held in the `param_env`.
88 fn type_needs_drop_given_env<'a,'tcx>(cx: &ty::ctxt<'tcx>,
90 param_env: &ty::ParameterEnvironment<'a,'tcx>) -> bool {
91 // Issue #22536: We first query type_moves_by_default. It sees a
92 // normalized version of the type, and therefore will definitely
93 // know whether the type implements Copy (and thus needs no
94 // cleanup/drop/zeroing) ...
95 let implements_copy = !ty.moves_by_default(param_env, DUMMY_SP);
97 if implements_copy { return false; }
99 // ... (issue #22536 continued) but as an optimization, still use
100 // prior logic of asking if the `needs_drop` bit is set; we need
101 // not zero non-Copy types if they have no destructor.
103 // FIXME(#22815): Note that calling `ty::type_contents` is a
104 // conservative heuristic; it may report that `needs_drop` is set
105 // when actual type does not actually have a destructor associated
106 // with it. But since `ty` absolutely did not have the `Copy`
107 // bound attached (see above), it is sound to treat it as having a
108 // destructor (e.g. zero its memory on move).
110 let contents = ty.type_contents(cx);
111 debug!("type_needs_drop ty={:?} contents={:?}", ty, contents);
112 contents.needs_drop(cx)
115 fn type_is_newtype_immediate<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
117 ty::TyStruct(def, substs) => {
118 let fields = &def.struct_variant().fields;
119 fields.len() == 1 && {
120 type_is_immediate(ccx, monomorphize::field_ty(ccx.tcx(), substs, &fields[0]))
127 pub fn type_is_immediate<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
128 use trans::machine::llsize_of_alloc;
129 use trans::type_of::sizing_type_of;
132 let simple = ty.is_scalar() ||
133 ty.is_unique() || ty.is_region_ptr() ||
134 type_is_newtype_immediate(ccx, ty) ||
136 if simple && !type_is_fat_ptr(tcx, ty) {
139 if !type_is_sized(tcx, ty) {
143 ty::TyStruct(..) | ty::TyEnum(..) | ty::TyTuple(..) | ty::TyArray(_, _) |
144 ty::TyClosure(..) => {
145 let llty = sizing_type_of(ccx, ty);
146 llsize_of_alloc(ccx, llty) <= llsize_of_alloc(ccx, ccx.int_type())
148 _ => type_is_zero_size(ccx, ty)
152 /// Identify types which have size zero at runtime.
153 pub fn type_is_zero_size<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
154 use trans::machine::llsize_of_alloc;
155 use trans::type_of::sizing_type_of;
156 let llty = sizing_type_of(ccx, ty);
157 llsize_of_alloc(ccx, llty) == 0
160 /// Identifies types which we declare to be equivalent to `void` in C for the purpose of function
161 /// return types. These are `()`, bot, and uninhabited enums. Note that all such types are also
162 /// zero-size, but not all zero-size types use a `void` return type (in order to aid with C ABI
164 pub fn return_type_is_void(ccx: &CrateContext, ty: Ty) -> bool {
165 ty.is_nil() || ty.is_empty(ccx.tcx())
168 /// Generates a unique symbol based off the name given. This is used to create
169 /// unique symbols for things like closures.
170 pub fn gensym_name(name: &str) -> PathElem {
171 let num = token::gensym(name).usize();
172 // use one colon which will get translated to a period by the mangler, and
173 // we're guaranteed that `num` is globally unique for this crate.
174 PathName(token::gensym(&format!("{}:{}", name, num)))
178 * A note on nomenclature of linking: "extern", "foreign", and "upcall".
180 * An "extern" is an LLVM symbol we wind up emitting an undefined external
181 * reference to. This means "we don't have the thing in this compilation unit,
182 * please make sure you link it in at runtime". This could be a reference to
183 * C code found in a C library, or rust code found in a rust crate.
185 * Most "externs" are implicitly declared (automatically) as a result of a
186 * user declaring an extern _module_ dependency; this causes the rust driver
187 * to locate an extern crate, scan its compilation metadata, and emit extern
188 * declarations for any symbols used by the declaring crate.
190 * A "foreign" is an extern that references C (or other non-rust ABI) code.
191 * There is no metadata to scan for extern references so in these cases either
192 * a header-digester like bindgen, or manual function prototypes, have to
193 * serve as declarators. So these are usually given explicitly as prototype
194 * declarations, in rust code, with ABI attributes on them noting which ABI to
197 * An "upcall" is a foreign call generated by the compiler (not corresponding
198 * to any user-written call in the code) into the runtime library, to perform
199 * some helper task such as bringing a task to life, allocating memory, etc.
203 #[derive(Copy, Clone)]
204 pub struct NodeIdAndSpan {
209 pub fn expr_info(expr: &hir::Expr) -> NodeIdAndSpan {
210 NodeIdAndSpan { id: expr.id, span: expr.span }
213 /// The concrete version of ty::FieldDef. The name is the field index if
214 /// the field is numeric.
215 pub struct Field<'tcx>(pub ast::Name, pub Ty<'tcx>);
217 /// The concrete version of ty::VariantDef
218 pub struct VariantInfo<'tcx> {
220 pub fields: Vec<Field<'tcx>>
223 impl<'tcx> VariantInfo<'tcx> {
224 pub fn from_ty(tcx: &ty::ctxt<'tcx>,
226 opt_def: Option<def::Def>)
230 ty::TyStruct(adt, substs) | ty::TyEnum(adt, substs) => {
231 let variant = match opt_def {
232 None => adt.struct_variant(),
233 Some(def) => adt.variant_of_def(def)
237 discr: variant.disr_val,
238 fields: variant.fields.iter().map(|f| {
239 Field(f.name, monomorphize::field_ty(tcx, substs, f))
244 ty::TyTuple(ref v) => {
247 fields: v.iter().enumerate().map(|(i, &t)| {
248 Field(token::intern(&i.to_string()), t)
254 tcx.sess.bug(&format!(
255 "cannot get field types from the type {:?}",
261 /// Return the variant corresponding to a given node (e.g. expr)
262 pub fn of_node(tcx: &ty::ctxt<'tcx>, ty: Ty<'tcx>, id: ast::NodeId) -> Self {
263 let node_def = tcx.def_map.borrow().get(&id).map(|v| v.full_def());
264 Self::from_ty(tcx, ty, node_def)
267 pub fn field_index(&self, name: ast::Name) -> usize {
268 self.fields.iter().position(|&Field(n,_)| n == name).unwrap_or_else(|| {
269 panic!("unknown field `{}`", name)
274 pub struct BuilderRef_res {
278 impl Drop for BuilderRef_res {
281 llvm::LLVMDisposeBuilder(self.b);
286 pub fn BuilderRef_res(b: BuilderRef) -> BuilderRef_res {
292 pub type ExternMap = FnvHashMap<String, ValueRef>;
294 pub fn validate_substs(substs: &Substs) {
295 assert!(!substs.types.needs_infer());
298 // work around bizarre resolve errors
299 type RvalueDatum<'tcx> = datum::Datum<'tcx, datum::Rvalue>;
300 pub type LvalueDatum<'tcx> = datum::Datum<'tcx, datum::Lvalue>;
302 #[derive(Clone, Debug)]
303 struct HintEntry<'tcx> {
304 // The datum for the dropflag-hint itself; note that many
305 // source-level Lvalues will be associated with the same
306 // dropflag-hint datum.
307 datum: cleanup::DropHintDatum<'tcx>,
310 pub struct DropFlagHintsMap<'tcx> {
311 // Maps NodeId for expressions that read/write unfragmented state
312 // to that state's drop-flag "hint." (A stack-local hint
313 // indicates either that (1.) it is certain that no-drop is
314 // needed, or (2.) inline drop-flag must be consulted.)
315 node_map: NodeMap<HintEntry<'tcx>>,
318 impl<'tcx> DropFlagHintsMap<'tcx> {
319 pub fn new() -> DropFlagHintsMap<'tcx> { DropFlagHintsMap { node_map: NodeMap() } }
320 pub fn has_hint(&self, id: ast::NodeId) -> bool { self.node_map.contains_key(&id) }
321 pub fn insert(&mut self, id: ast::NodeId, datum: cleanup::DropHintDatum<'tcx>) {
322 self.node_map.insert(id, HintEntry { datum: datum });
324 pub fn hint_datum(&self, id: ast::NodeId) -> Option<cleanup::DropHintDatum<'tcx>> {
325 self.node_map.get(&id).map(|t|t.datum)
329 // Function context. Every LLVM function we create will have one of
331 pub struct FunctionContext<'a, 'tcx: 'a> {
332 // The ValueRef returned from a call to llvm::LLVMAddFunction; the
333 // address of the first instruction in the sequence of
334 // instructions for this function that will go in the .text
335 // section of the executable we're generating.
338 // always an empty parameter-environment NOTE: @jroesch another use of ParamEnv
339 pub param_env: ty::ParameterEnvironment<'a, 'tcx>,
341 // The environment argument in a closure.
342 pub llenv: Option<ValueRef>,
344 // A pointer to where to store the return value. If the return type is
345 // immediate, this points to an alloca in the function. Otherwise, it's a
346 // pointer to the hidden first parameter of the function. After function
347 // construction, this should always be Some.
348 pub llretslotptr: Cell<Option<ValueRef>>,
350 // These pub elements: "hoisted basic blocks" containing
351 // administrative activities that have to happen in only one place in
352 // the function, due to LLVM's quirks.
353 // A marker for the place where we want to insert the function's static
354 // allocas, so that LLVM will coalesce them into a single alloca call.
355 pub alloca_insert_pt: Cell<Option<ValueRef>>,
356 pub llreturn: Cell<Option<BasicBlockRef>>,
358 // If the function has any nested return's, including something like:
359 // fn foo() -> Option<Foo> { Some(Foo { x: return None }) }, then
360 // we use a separate alloca for each return
361 pub needs_ret_allocas: bool,
363 // The a value alloca'd for calls to upcalls.rust_personality. Used when
364 // outputting the resume instruction.
365 pub personality: Cell<Option<ValueRef>>,
367 // True if the caller expects this fn to use the out pointer to
368 // return. Either way, your code should write into the slot llretslotptr
369 // points to, but if this value is false, that slot will be a local alloca.
370 pub caller_expects_out_pointer: bool,
372 // Maps the DefId's for local variables to the allocas created for
373 // them in llallocas.
374 pub lllocals: RefCell<NodeMap<LvalueDatum<'tcx>>>,
376 // Same as above, but for closure upvars
377 pub llupvars: RefCell<NodeMap<ValueRef>>,
379 // Carries info about drop-flags for local bindings (longer term,
380 // paths) for the code being compiled.
381 pub lldropflag_hints: RefCell<DropFlagHintsMap<'tcx>>,
383 // The NodeId of the function, or -1 if it doesn't correspond to
384 // a user-defined function.
387 // If this function is being monomorphized, this contains the type
388 // substitutions used.
389 pub param_substs: &'tcx Substs<'tcx>,
391 // The source span and nesting context where this function comes from, for
392 // error reporting and symbol generation.
393 pub span: Option<Span>,
395 // The arena that blocks are allocated from.
396 pub block_arena: &'a TypedArena<BlockS<'a, 'tcx>>,
398 // This function's enclosing crate context.
399 pub ccx: &'a CrateContext<'a, 'tcx>,
401 // Used and maintained by the debuginfo module.
402 pub debug_context: debuginfo::FunctionDebugContext,
405 pub scopes: RefCell<Vec<cleanup::CleanupScope<'a, 'tcx>>>,
407 pub cfg: Option<cfg::CFG>,
410 impl<'a, 'tcx> FunctionContext<'a, 'tcx> {
411 pub fn arg_offset(&self) -> usize {
412 self.env_arg_pos() + if self.llenv.is_some() { 1 } else { 0 }
415 pub fn env_arg_pos(&self) -> usize {
416 if self.caller_expects_out_pointer {
423 pub fn cleanup(&self) {
425 llvm::LLVMInstructionEraseFromParent(self.alloca_insert_pt
431 pub fn get_llreturn(&self) -> BasicBlockRef {
432 if self.llreturn.get().is_none() {
434 self.llreturn.set(Some(unsafe {
435 llvm::LLVMAppendBasicBlockInContext(self.ccx.llcx(), self.llfn,
436 "return\0".as_ptr() as *const _)
440 self.llreturn.get().unwrap()
443 pub fn get_ret_slot(&self, bcx: Block<'a, 'tcx>,
444 output: ty::FnOutput<'tcx>,
445 name: &str) -> ValueRef {
446 if self.needs_ret_allocas {
447 base::alloca(bcx, match output {
448 ty::FnConverging(output_type) => type_of::type_of(bcx.ccx(), output_type),
449 ty::FnDiverging => Type::void(bcx.ccx())
452 self.llretslotptr.get().unwrap()
456 pub fn new_block(&'a self,
459 opt_node_id: Option<ast::NodeId>)
462 let name = CString::new(name).unwrap();
463 let llbb = llvm::LLVMAppendBasicBlockInContext(self.ccx.llcx(),
466 BlockS::new(llbb, is_lpad, opt_node_id, self)
470 pub fn new_id_block(&'a self,
472 node_id: ast::NodeId)
474 self.new_block(false, name, Some(node_id))
477 pub fn new_temp_block(&'a self,
480 self.new_block(false, name, None)
483 pub fn join_blocks(&'a self,
485 in_cxs: &[Block<'a, 'tcx>])
487 let out = self.new_id_block("join", id);
488 let mut reachable = false;
490 if !bcx.unreachable.get() {
491 build::Br(*bcx, out.llbb, DebugLoc::None);
496 build::Unreachable(out);
501 pub fn monomorphize<T>(&self, value: &T) -> T
502 where T : TypeFoldable<'tcx> + HasTypeFlags
504 monomorphize::apply_param_substs(self.ccx.tcx(),
509 /// This is the same as `common::type_needs_drop`, except that it
510 /// may use or update caches within this `FunctionContext`.
511 pub fn type_needs_drop(&self, ty: Ty<'tcx>) -> bool {
512 type_needs_drop_given_env(self.ccx.tcx(), ty, &self.param_env)
515 pub fn eh_personality(&self) -> ValueRef {
516 // The exception handling personality function.
518 // If our compilation unit has the `eh_personality` lang item somewhere
519 // within it, then we just need to translate that. Otherwise, we're
520 // building an rlib which will depend on some upstream implementation of
521 // this function, so we just codegen a generic reference to it. We don't
522 // specify any of the types for the function, we just make it a symbol
523 // that LLVM can later use.
525 // Note that MSVC is a little special here in that we don't use the
526 // `eh_personality` lang item at all. Currently LLVM has support for
527 // both Dwarf and SEH unwind mechanisms for MSVC targets and uses the
528 // *name of the personality function* to decide what kind of unwind side
529 // tables/landing pads to emit. It looks like Dwarf is used by default,
530 // injecting a dependency on the `_Unwind_Resume` symbol for resuming
531 // an "exception", but for MSVC we want to force SEH. This means that we
532 // can't actually have the personality function be our standard
533 // `rust_eh_personality` function, but rather we wired it up to the
534 // CRT's custom personality function, which forces LLVM to consider
535 // landing pads as "landing pads for SEH".
536 let target = &self.ccx.sess().target.target;
537 match self.ccx.tcx().lang_items.eh_personality() {
538 Some(def_id) if !base::wants_msvc_seh(self.ccx.sess()) => {
539 callee::trans_fn_ref(self.ccx, def_id, ExprId(0),
540 self.param_substs).val
543 let mut personality = self.ccx.eh_personality().borrow_mut();
545 Some(llpersonality) => llpersonality,
547 let name = if !base::wants_msvc_seh(self.ccx.sess()) {
548 "rust_eh_personality"
549 } else if target.arch == "x86" {
552 "__C_specific_handler"
554 let fty = Type::variadic_func(&[], &Type::i32(self.ccx));
555 let f = declare::declare_cfn(self.ccx, name, fty,
556 self.ccx.tcx().types.i32);
557 *personality = Some(f);
565 /// By default, LLVM lowers `resume` instructions into calls to `_Unwind_Resume`
566 /// defined in libgcc, however, unlike personality routines, there is no easy way to
567 /// override that symbol. This method injects a local-scoped `_Unwind_Resume` function
568 /// which immediately defers to the user-defined `eh_unwind_resume` lang item.
569 pub fn inject_unwind_resume_hook(&self) {
571 if !ccx.sess().target.target.options.custom_unwind_resume ||
572 ccx.unwind_resume_hooked().get() {
576 let new_resume = match ccx.tcx().lang_items.eh_unwind_resume() {
577 Some(did) => callee::trans_fn_ref(ccx, did, ExprId(0), &self.param_substs).val,
579 let fty = Type::variadic_func(&[], &Type::void(self.ccx));
580 declare::declare_cfn(self.ccx, "rust_eh_unwind_resume", fty,
581 self.ccx.tcx().mk_nil())
586 let resume_type = Type::func(&[Type::i8(ccx).ptr_to()], &Type::void(ccx));
587 let old_resume = llvm::LLVMAddFunction(ccx.llmod(),
588 "_Unwind_Resume\0".as_ptr() as *const _,
589 resume_type.to_ref());
590 llvm::SetLinkage(old_resume, llvm::InternalLinkage);
591 let llbb = llvm::LLVMAppendBasicBlockInContext(ccx.llcx(),
593 "\0".as_ptr() as *const _);
594 let builder = ccx.builder();
595 builder.position_at_end(llbb);
596 builder.call(new_resume, &[llvm::LLVMGetFirstParam(old_resume)], None);
597 builder.unreachable(); // it should never return
599 // Until DwarfEHPrepare pass has run, _Unwind_Resume is not referenced by any live code
600 // and is subject to dead code elimination. Here we add _Unwind_Resume to @llvm.globals
602 let i8p_ty = Type::i8p(ccx);
603 let used_ty = Type::array(&i8p_ty, 1);
604 let used = llvm::LLVMAddGlobal(ccx.llmod(), used_ty.to_ref(),
605 "llvm.used\0".as_ptr() as *const _);
606 let old_resume = llvm::LLVMConstBitCast(old_resume, i8p_ty.to_ref());
607 llvm::LLVMSetInitializer(used, C_array(i8p_ty, &[old_resume]));
608 llvm::SetLinkage(used, llvm::AppendingLinkage);
609 llvm::LLVMSetSection(used, "llvm.metadata\0".as_ptr() as *const _)
611 ccx.unwind_resume_hooked().set(true);
615 // Basic block context. We create a block context for each basic block
616 // (single-entry, single-exit sequence of instructions) we generate from Rust
617 // code. Each basic block we generate is attached to a function, typically
618 // with many basic blocks per function. All the basic blocks attached to a
619 // function are organized as a directed graph.
620 pub struct BlockS<'blk, 'tcx: 'blk> {
621 // The BasicBlockRef returned from a call to
622 // llvm::LLVMAppendBasicBlock(llfn, name), which adds a basic
623 // block to the function pointed to by llfn. We insert
624 // instructions into that block by way of this block context.
625 // The block pointing to this one in the function's digraph.
626 pub llbb: BasicBlockRef,
627 pub terminated: Cell<bool>,
628 pub unreachable: Cell<bool>,
630 // Is this block part of a landing pad?
633 // AST node-id associated with this block, if any. Used for
634 // debugging purposes only.
635 pub opt_node_id: Option<ast::NodeId>,
637 // The function context for the function to which this block is
639 pub fcx: &'blk FunctionContext<'blk, 'tcx>,
642 pub type Block<'blk, 'tcx> = &'blk BlockS<'blk, 'tcx>;
644 impl<'blk, 'tcx> BlockS<'blk, 'tcx> {
645 pub fn new(llbb: BasicBlockRef,
647 opt_node_id: Option<ast::NodeId>,
648 fcx: &'blk FunctionContext<'blk, 'tcx>)
649 -> Block<'blk, 'tcx> {
650 fcx.block_arena.alloc(BlockS {
652 terminated: Cell::new(false),
653 unreachable: Cell::new(false),
655 opt_node_id: opt_node_id,
660 pub fn ccx(&self) -> &'blk CrateContext<'blk, 'tcx> {
663 pub fn tcx(&self) -> &'blk ty::ctxt<'tcx> {
666 pub fn sess(&self) -> &'blk Session { self.fcx.ccx.sess() }
668 pub fn name(&self, name: ast::Name) -> String {
672 pub fn node_id_to_string(&self, id: ast::NodeId) -> String {
673 self.tcx().map.node_to_string(id).to_string()
676 pub fn def(&self, nid: ast::NodeId) -> def::Def {
677 match self.tcx().def_map.borrow().get(&nid) {
678 Some(v) => v.full_def(),
680 self.tcx().sess.bug(&format!(
681 "no def associated with node id {}", nid));
686 pub fn val_to_string(&self, val: ValueRef) -> String {
687 self.ccx().tn().val_to_string(val)
690 pub fn llty_str(&self, ty: Type) -> String {
691 self.ccx().tn().type_to_string(ty)
694 pub fn to_str(&self) -> String {
695 format!("[block {:p}]", self)
698 pub fn monomorphize<T>(&self, value: &T) -> T
699 where T : TypeFoldable<'tcx> + HasTypeFlags
701 monomorphize::apply_param_substs(self.tcx(),
702 self.fcx.param_substs,
707 pub struct Result<'blk, 'tcx: 'blk> {
708 pub bcx: Block<'blk, 'tcx>,
712 impl<'b, 'tcx> Result<'b, 'tcx> {
713 pub fn new(bcx: Block<'b, 'tcx>, val: ValueRef) -> Result<'b, 'tcx> {
721 pub fn val_ty(v: ValueRef) -> Type {
723 Type::from_ref(llvm::LLVMTypeOf(v))
727 // LLVM constant constructors.
728 pub fn C_null(t: Type) -> ValueRef {
730 llvm::LLVMConstNull(t.to_ref())
734 pub fn C_undef(t: Type) -> ValueRef {
736 llvm::LLVMGetUndef(t.to_ref())
740 pub fn C_integral(t: Type, u: u64, sign_extend: bool) -> ValueRef {
742 llvm::LLVMConstInt(t.to_ref(), u, sign_extend as Bool)
746 pub fn C_floating(s: &str, t: Type) -> ValueRef {
748 let s = CString::new(s).unwrap();
749 llvm::LLVMConstRealOfString(t.to_ref(), s.as_ptr())
753 pub fn C_nil(ccx: &CrateContext) -> ValueRef {
754 C_struct(ccx, &[], false)
757 pub fn C_bool(ccx: &CrateContext, val: bool) -> ValueRef {
758 C_integral(Type::i1(ccx), val as u64, false)
761 pub fn C_i32(ccx: &CrateContext, i: i32) -> ValueRef {
762 C_integral(Type::i32(ccx), i as u64, true)
765 pub fn C_u32(ccx: &CrateContext, i: u32) -> ValueRef {
766 C_integral(Type::i32(ccx), i as u64, false)
769 pub fn C_u64(ccx: &CrateContext, i: u64) -> ValueRef {
770 C_integral(Type::i64(ccx), i, false)
773 pub fn C_int<I: AsI64>(ccx: &CrateContext, i: I) -> ValueRef {
776 let bit_size = machine::llbitsize_of_real(ccx, ccx.int_type());
779 // make sure it doesn't overflow
780 assert!(v < (1<<(bit_size-1)) && v >= -(1<<(bit_size-1)));
783 C_integral(ccx.int_type(), v as u64, true)
786 pub fn C_uint<I: AsU64>(ccx: &CrateContext, i: I) -> ValueRef {
789 let bit_size = machine::llbitsize_of_real(ccx, ccx.int_type());
792 // make sure it doesn't overflow
793 assert!(v < (1<<bit_size));
796 C_integral(ccx.int_type(), v, false)
799 pub trait AsI64 { fn as_i64(self) -> i64; }
800 pub trait AsU64 { fn as_u64(self) -> u64; }
802 // FIXME: remove the intptr conversions, because they
803 // are host-architecture-dependent
804 impl AsI64 for i64 { fn as_i64(self) -> i64 { self as i64 }}
805 impl AsI64 for i32 { fn as_i64(self) -> i64 { self as i64 }}
806 impl AsI64 for isize { fn as_i64(self) -> i64 { self as i64 }}
808 impl AsU64 for u64 { fn as_u64(self) -> u64 { self as u64 }}
809 impl AsU64 for u32 { fn as_u64(self) -> u64 { self as u64 }}
810 impl AsU64 for usize { fn as_u64(self) -> u64 { self as u64 }}
812 pub fn C_u8(ccx: &CrateContext, i: u8) -> ValueRef {
813 C_integral(Type::i8(ccx), i as u64, false)
817 // This is a 'c-like' raw string, which differs from
818 // our boxed-and-length-annotated strings.
819 pub fn C_cstr(cx: &CrateContext, s: InternedString, null_terminated: bool) -> ValueRef {
821 match cx.const_cstr_cache().borrow().get(&s) {
822 Some(&llval) => return llval,
826 let sc = llvm::LLVMConstStringInContext(cx.llcx(),
827 s.as_ptr() as *const c_char,
829 !null_terminated as Bool);
831 let gsym = token::gensym("str");
832 let sym = format!("str{}", gsym.usize());
833 let g = declare::define_global(cx, &sym[..], val_ty(sc)).unwrap_or_else(||{
834 cx.sess().bug(&format!("symbol `{}` is already defined", sym));
836 llvm::LLVMSetInitializer(g, sc);
837 llvm::LLVMSetGlobalConstant(g, True);
838 llvm::SetLinkage(g, llvm::InternalLinkage);
840 cx.const_cstr_cache().borrow_mut().insert(s, g);
845 // NB: Do not use `do_spill_noroot` to make this into a constant string, or
846 // you will be kicked off fast isel. See issue #4352 for an example of this.
847 pub fn C_str_slice(cx: &CrateContext, s: InternedString) -> ValueRef {
849 let cs = consts::ptrcast(C_cstr(cx, s, false), Type::i8p(cx));
850 C_named_struct(cx.tn().find_type("str_slice").unwrap(), &[cs, C_uint(cx, len)])
853 pub fn C_struct(cx: &CrateContext, elts: &[ValueRef], packed: bool) -> ValueRef {
854 C_struct_in_context(cx.llcx(), elts, packed)
857 pub fn C_struct_in_context(llcx: ContextRef, elts: &[ValueRef], packed: bool) -> ValueRef {
859 llvm::LLVMConstStructInContext(llcx,
860 elts.as_ptr(), elts.len() as c_uint,
865 pub fn C_named_struct(t: Type, elts: &[ValueRef]) -> ValueRef {
867 llvm::LLVMConstNamedStruct(t.to_ref(), elts.as_ptr(), elts.len() as c_uint)
871 pub fn C_array(ty: Type, elts: &[ValueRef]) -> ValueRef {
873 return llvm::LLVMConstArray(ty.to_ref(), elts.as_ptr(), elts.len() as c_uint);
877 pub fn C_vector(elts: &[ValueRef]) -> ValueRef {
879 return llvm::LLVMConstVector(elts.as_ptr(), elts.len() as c_uint);
883 pub fn C_bytes(cx: &CrateContext, bytes: &[u8]) -> ValueRef {
884 C_bytes_in_context(cx.llcx(), bytes)
887 pub fn C_bytes_in_context(llcx: ContextRef, bytes: &[u8]) -> ValueRef {
889 let ptr = bytes.as_ptr() as *const c_char;
890 return llvm::LLVMConstStringInContext(llcx, ptr, bytes.len() as c_uint, True);
894 pub fn const_get_elt(cx: &CrateContext, v: ValueRef, us: &[c_uint])
897 let r = llvm::LLVMConstExtractValue(v, us.as_ptr(), us.len() as c_uint);
899 debug!("const_get_elt(v={}, us={:?}, r={})",
900 cx.tn().val_to_string(v), us, cx.tn().val_to_string(r));
906 pub fn const_to_int(v: ValueRef) -> i64 {
908 llvm::LLVMConstIntGetSExtValue(v)
912 pub fn const_to_uint(v: ValueRef) -> u64 {
914 llvm::LLVMConstIntGetZExtValue(v)
918 fn is_const_integral(v: ValueRef) -> bool {
920 !llvm::LLVMIsAConstantInt(v).is_null()
924 pub fn const_to_opt_int(v: ValueRef) -> Option<i64> {
926 if is_const_integral(v) {
927 Some(llvm::LLVMConstIntGetSExtValue(v))
934 pub fn const_to_opt_uint(v: ValueRef) -> Option<u64> {
936 if is_const_integral(v) {
937 Some(llvm::LLVMConstIntGetZExtValue(v))
944 pub fn is_undef(val: ValueRef) -> bool {
946 llvm::LLVMIsUndef(val) != False
950 #[allow(dead_code)] // potentially useful
951 pub fn is_null(val: ValueRef) -> bool {
953 llvm::LLVMIsNull(val) != False
957 pub fn monomorphize_type<'blk, 'tcx>(bcx: &BlockS<'blk, 'tcx>, t: Ty<'tcx>) -> Ty<'tcx> {
958 bcx.fcx.monomorphize(&t)
961 pub fn node_id_type<'blk, 'tcx>(bcx: &BlockS<'blk, 'tcx>, id: ast::NodeId) -> Ty<'tcx> {
963 let t = tcx.node_id_to_type(id);
964 monomorphize_type(bcx, t)
967 pub fn expr_ty<'blk, 'tcx>(bcx: &BlockS<'blk, 'tcx>, ex: &hir::Expr) -> Ty<'tcx> {
968 node_id_type(bcx, ex.id)
971 pub fn expr_ty_adjusted<'blk, 'tcx>(bcx: &BlockS<'blk, 'tcx>, ex: &hir::Expr) -> Ty<'tcx> {
972 monomorphize_type(bcx, bcx.tcx().expr_ty_adjusted(ex))
975 /// Attempts to resolve an obligation. The result is a shallow vtable resolution -- meaning that we
976 /// do not (necessarily) resolve all nested obligations on the impl. Note that type check should
977 /// guarantee to us that all nested obligations *could be* resolved if we wanted to.
978 pub fn fulfill_obligation<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
980 trait_ref: ty::PolyTraitRef<'tcx>)
981 -> traits::Vtable<'tcx, ()>
985 // Remove any references to regions; this helps improve caching.
986 let trait_ref = tcx.erase_regions(&trait_ref);
988 // First check the cache.
989 match ccx.trait_cache().borrow().get(&trait_ref) {
991 info!("Cache hit: {:?}", trait_ref);
992 return (*vtable).clone();
997 debug!("trans fulfill_obligation: trait_ref={:?} def_id={:?}",
998 trait_ref, trait_ref.def_id());
1001 // Do the initial selection for the obligation. This yields the
1002 // shallow result we are looking for -- that is, what specific impl.
1003 let infcx = infer::normalizing_infer_ctxt(tcx, &tcx.tables);
1004 let mut selcx = traits::SelectionContext::new(&infcx);
1007 traits::Obligation::new(traits::ObligationCause::misc(span, ast::DUMMY_NODE_ID),
1008 trait_ref.to_poly_trait_predicate());
1009 let selection = match selcx.select(&obligation) {
1010 Ok(Some(selection)) => selection,
1012 // Ambiguity can happen when monomorphizing during trans
1013 // expands to some humongo type that never occurred
1014 // statically -- this humongo type can then overflow,
1015 // leading to an ambiguous result. So report this as an
1016 // overflow bug, since I believe this is the only case
1017 // where ambiguity can result.
1018 debug!("Encountered ambiguity selecting `{:?}` during trans, \
1019 presuming due to overflow",
1021 ccx.sess().span_fatal(
1023 "reached the recursion limit during monomorphization");
1028 &format!("Encountered error `{:?}` selecting `{:?}` during trans",
1034 // Currently, we use a fulfillment context to completely resolve
1035 // all nested obligations. This is because they can inform the
1036 // inference of the impl's type parameters.
1037 let mut fulfill_cx = infcx.fulfillment_cx.borrow_mut();
1038 let vtable = selection.map(|predicate| {
1039 fulfill_cx.register_predicate_obligation(&infcx, predicate);
1041 let vtable = infer::drain_fulfillment_cx_or_panic(
1042 span, &infcx, &mut fulfill_cx, &vtable
1045 info!("Cache miss: {:?} => {:?}", trait_ref, vtable);
1047 ccx.trait_cache().borrow_mut().insert(trait_ref, vtable.clone());
1052 /// Normalizes the predicates and checks whether they hold. If this
1053 /// returns false, then either normalize encountered an error or one
1054 /// of the predicates did not hold. Used when creating vtables to
1055 /// check for unsatisfiable methods.
1056 pub fn normalize_and_test_predicates<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
1057 predicates: Vec<ty::Predicate<'tcx>>)
1060 debug!("normalize_and_test_predicates(predicates={:?})",
1063 let tcx = ccx.tcx();
1064 let infcx = infer::normalizing_infer_ctxt(tcx, &tcx.tables);
1065 let mut selcx = traits::SelectionContext::new(&infcx);
1066 let mut fulfill_cx = infcx.fulfillment_cx.borrow_mut();
1067 let cause = traits::ObligationCause::dummy();
1068 let traits::Normalized { value: predicates, obligations } =
1069 traits::normalize(&mut selcx, cause.clone(), &predicates);
1070 for obligation in obligations {
1071 fulfill_cx.register_predicate_obligation(&infcx, obligation);
1073 for predicate in predicates {
1074 let obligation = traits::Obligation::new(cause.clone(), predicate);
1075 fulfill_cx.register_predicate_obligation(&infcx, obligation);
1078 infer::drain_fulfillment_cx(&infcx, &mut fulfill_cx, &()).is_ok()
1081 // Key used to lookup values supplied for type parameters in an expr.
1082 #[derive(Copy, Clone, PartialEq, Debug)]
1083 pub enum ExprOrMethodCall {
1084 // Type parameters for a path like `None::<int>`
1085 ExprId(ast::NodeId),
1087 // Type parameters for a method call like `a.foo::<int>()`
1088 MethodCallKey(ty::MethodCall)
1091 pub fn node_id_substs<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
1092 node: ExprOrMethodCall,
1093 param_substs: &subst::Substs<'tcx>)
1094 -> subst::Substs<'tcx> {
1095 let tcx = ccx.tcx();
1097 let substs = match node {
1099 tcx.node_id_item_substs(id).substs
1101 MethodCallKey(method_call) => {
1102 tcx.tables.borrow().method_map[&method_call].substs.clone()
1106 if substs.types.needs_infer() {
1107 tcx.sess.bug(&format!("type parameters for node {:?} include inference types: {:?}",
1111 monomorphize::apply_param_substs(tcx,
1113 &substs.erase_regions())
1116 pub fn langcall(bcx: Block,
1121 match bcx.tcx().lang_items.require(li) {
1124 let msg = format!("{} {}", msg, s);
1126 Some(span) => bcx.tcx().sess.span_fatal(span, &msg[..]),
1127 None => bcx.tcx().sess.fatal(&msg[..]),
1133 /// Return the VariantDef corresponding to an inlined variant node
1134 pub fn inlined_variant_def<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
1135 inlined_vid: ast::NodeId)
1136 -> ty::VariantDef<'tcx>
1139 let ctor_ty = ccx.tcx().node_id_to_type(inlined_vid);
1140 debug!("inlined_variant_def: ctor_ty={:?} inlined_vid={:?}", ctor_ty,
1142 let adt_def = match ctor_ty.sty {
1143 ty::TyBareFn(_, &ty::BareFnTy { sig: ty::Binder(ty::FnSig {
1144 output: ty::FnConverging(ty), ..
1147 }.ty_adt_def().unwrap();
1148 adt_def.variants.iter().find(|v| {
1149 DefId::local(inlined_vid) == v.did ||
1150 ccx.external().borrow().get(&v.did) == Some(&Some(inlined_vid))
1151 }).unwrap_or_else(|| {
1152 ccx.sess().bug(&format!("no variant for {:?}::{}", adt_def, inlined_vid))