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, TypeKind};
20 use llvm::{True, False, Bool, OperandBundleDef};
23 use middle::def_id::DefId;
25 use middle::lang_items::LangItem;
26 use middle::subst::{self, Substs};
29 use trans::builder::Builder;
34 use trans::debuginfo::{self, DebugLoc};
37 use trans::monomorphize;
38 use trans::type_::Type;
41 use middle::ty::{self, Ty};
42 use middle::ty::fold::{TypeFolder, TypeFoldable};
44 use rustc::mir::repr::Mir;
45 use util::nodemap::{FnvHashMap, NodeMap};
47 use arena::TypedArena;
48 use libc::{c_uint, c_char};
50 use std::ffi::CString;
51 use std::cell::{Cell, RefCell};
54 use syntax::codemap::{DUMMY_SP, Span};
55 use syntax::parse::token::InternedString;
56 use syntax::parse::token;
58 pub use trans::context::CrateContext;
60 /// Is the type's representation size known at compile time?
61 pub fn type_is_sized<'tcx>(tcx: &ty::ctxt<'tcx>, ty: Ty<'tcx>) -> bool {
62 ty.is_sized(&tcx.empty_parameter_environment(), DUMMY_SP)
65 pub fn type_is_fat_ptr<'tcx>(cx: &ty::ctxt<'tcx>, ty: Ty<'tcx>) -> bool {
67 ty::TyRawPtr(ty::TypeAndMut{ty, ..}) |
68 ty::TyRef(_, ty::TypeAndMut{ty, ..}) |
70 !type_is_sized(cx, ty)
78 fn type_is_newtype_immediate<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
80 ty::TyStruct(def, substs) => {
81 let fields = &def.struct_variant().fields;
82 fields.len() == 1 && {
83 type_is_immediate(ccx, monomorphize::field_ty(ccx.tcx(), substs, &fields[0]))
90 pub fn type_is_immediate<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
91 use trans::machine::llsize_of_alloc;
92 use trans::type_of::sizing_type_of;
95 let simple = ty.is_scalar() ||
96 ty.is_unique() || ty.is_region_ptr() ||
97 type_is_newtype_immediate(ccx, ty) ||
99 if simple && !type_is_fat_ptr(tcx, ty) {
102 if !type_is_sized(tcx, ty) {
106 ty::TyStruct(..) | ty::TyEnum(..) | ty::TyTuple(..) | ty::TyArray(_, _) |
107 ty::TyClosure(..) => {
108 let llty = sizing_type_of(ccx, ty);
109 llsize_of_alloc(ccx, llty) <= llsize_of_alloc(ccx, ccx.int_type())
111 _ => type_is_zero_size(ccx, ty)
115 /// Identify types which have size zero at runtime.
116 pub fn type_is_zero_size<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
117 use trans::machine::llsize_of_alloc;
118 use trans::type_of::sizing_type_of;
119 let llty = sizing_type_of(ccx, ty);
120 llsize_of_alloc(ccx, llty) == 0
123 /// Identifies types which we declare to be equivalent to `void` in C for the purpose of function
124 /// return types. These are `()`, bot, uninhabited enums and all other zero-sized types.
125 pub fn return_type_is_void<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
126 ty.is_nil() || ty.is_empty(ccx.tcx()) || type_is_zero_size(ccx, ty)
129 /// Generates a unique symbol based off the name given. This is used to create
130 /// unique symbols for things like closures.
131 pub fn gensym_name(name: &str) -> ast::Name {
132 let num = token::gensym(name).0;
133 // use one colon which will get translated to a period by the mangler, and
134 // we're guaranteed that `num` is globally unique for this crate.
135 token::gensym(&format!("{}:{}", name, num))
139 * A note on nomenclature of linking: "extern", "foreign", and "upcall".
141 * An "extern" is an LLVM symbol we wind up emitting an undefined external
142 * reference to. This means "we don't have the thing in this compilation unit,
143 * please make sure you link it in at runtime". This could be a reference to
144 * C code found in a C library, or rust code found in a rust crate.
146 * Most "externs" are implicitly declared (automatically) as a result of a
147 * user declaring an extern _module_ dependency; this causes the rust driver
148 * to locate an extern crate, scan its compilation metadata, and emit extern
149 * declarations for any symbols used by the declaring crate.
151 * A "foreign" is an extern that references C (or other non-rust ABI) code.
152 * There is no metadata to scan for extern references so in these cases either
153 * a header-digester like bindgen, or manual function prototypes, have to
154 * serve as declarators. So these are usually given explicitly as prototype
155 * declarations, in rust code, with ABI attributes on them noting which ABI to
158 * An "upcall" is a foreign call generated by the compiler (not corresponding
159 * to any user-written call in the code) into the runtime library, to perform
160 * some helper task such as bringing a task to life, allocating memory, etc.
166 #[derive(Copy, Clone)]
167 pub struct NodeIdAndSpan {
172 pub fn expr_info(expr: &hir::Expr) -> NodeIdAndSpan {
173 NodeIdAndSpan { id: expr.id, span: expr.span }
176 /// The concrete version of ty::FieldDef. The name is the field index if
177 /// the field is numeric.
178 pub struct Field<'tcx>(pub ast::Name, pub Ty<'tcx>);
180 /// The concrete version of ty::VariantDef
181 pub struct VariantInfo<'tcx> {
183 pub fields: Vec<Field<'tcx>>
186 impl<'tcx> VariantInfo<'tcx> {
187 pub fn from_ty(tcx: &ty::ctxt<'tcx>,
189 opt_def: Option<Def>)
193 ty::TyStruct(adt, substs) | ty::TyEnum(adt, substs) => {
194 let variant = match opt_def {
195 None => adt.struct_variant(),
196 Some(def) => adt.variant_of_def(def)
200 discr: Disr::from(variant.disr_val),
201 fields: variant.fields.iter().map(|f| {
202 Field(f.name, monomorphize::field_ty(tcx, substs, f))
207 ty::TyTuple(ref v) => {
210 fields: v.iter().enumerate().map(|(i, &t)| {
211 Field(token::intern(&i.to_string()), t)
217 tcx.sess.bug(&format!(
218 "cannot get field types from the type {:?}",
224 /// Return the variant corresponding to a given node (e.g. expr)
225 pub fn of_node(tcx: &ty::ctxt<'tcx>, ty: Ty<'tcx>, id: ast::NodeId) -> Self {
226 let node_def = tcx.def_map.borrow().get(&id).map(|v| v.full_def());
227 Self::from_ty(tcx, ty, node_def)
230 pub fn field_index(&self, name: ast::Name) -> usize {
231 self.fields.iter().position(|&Field(n,_)| n == name).unwrap_or_else(|| {
232 panic!("unknown field `{}`", name)
237 pub struct BuilderRef_res {
241 impl Drop for BuilderRef_res {
244 llvm::LLVMDisposeBuilder(self.b);
249 pub fn BuilderRef_res(b: BuilderRef) -> BuilderRef_res {
255 pub type ExternMap = FnvHashMap<String, ValueRef>;
257 pub fn validate_substs(substs: &Substs) {
258 assert!(!substs.types.needs_infer());
261 // work around bizarre resolve errors
262 type RvalueDatum<'tcx> = datum::Datum<'tcx, datum::Rvalue>;
263 pub type LvalueDatum<'tcx> = datum::Datum<'tcx, datum::Lvalue>;
265 #[derive(Clone, Debug)]
266 struct HintEntry<'tcx> {
267 // The datum for the dropflag-hint itself; note that many
268 // source-level Lvalues will be associated with the same
269 // dropflag-hint datum.
270 datum: cleanup::DropHintDatum<'tcx>,
273 pub struct DropFlagHintsMap<'tcx> {
274 // Maps NodeId for expressions that read/write unfragmented state
275 // to that state's drop-flag "hint." (A stack-local hint
276 // indicates either that (1.) it is certain that no-drop is
277 // needed, or (2.) inline drop-flag must be consulted.)
278 node_map: NodeMap<HintEntry<'tcx>>,
281 impl<'tcx> DropFlagHintsMap<'tcx> {
282 pub fn new() -> DropFlagHintsMap<'tcx> { DropFlagHintsMap { node_map: NodeMap() } }
283 pub fn has_hint(&self, id: ast::NodeId) -> bool { self.node_map.contains_key(&id) }
284 pub fn insert(&mut self, id: ast::NodeId, datum: cleanup::DropHintDatum<'tcx>) {
285 self.node_map.insert(id, HintEntry { datum: datum });
287 pub fn hint_datum(&self, id: ast::NodeId) -> Option<cleanup::DropHintDatum<'tcx>> {
288 self.node_map.get(&id).map(|t|t.datum)
292 // Function context. Every LLVM function we create will have one of
294 pub struct FunctionContext<'a, 'tcx: 'a> {
295 // The MIR for this function. At present, this is optional because
296 // we only have MIR available for things that are local to the
298 pub mir: Option<&'a Mir<'tcx>>,
300 // The ValueRef returned from a call to llvm::LLVMAddFunction; the
301 // address of the first instruction in the sequence of
302 // instructions for this function that will go in the .text
303 // section of the executable we're generating.
306 // always an empty parameter-environment NOTE: @jroesch another use of ParamEnv
307 pub param_env: ty::ParameterEnvironment<'a, 'tcx>,
309 // The environment argument in a closure.
310 pub llenv: Option<ValueRef>,
312 // A pointer to where to store the return value. If the return type is
313 // immediate, this points to an alloca in the function. Otherwise, it's a
314 // pointer to the hidden first parameter of the function. After function
315 // construction, this should always be Some.
316 pub llretslotptr: Cell<Option<ValueRef>>,
318 // These pub elements: "hoisted basic blocks" containing
319 // administrative activities that have to happen in only one place in
320 // the function, due to LLVM's quirks.
321 // A marker for the place where we want to insert the function's static
322 // allocas, so that LLVM will coalesce them into a single alloca call.
323 pub alloca_insert_pt: Cell<Option<ValueRef>>,
324 pub llreturn: Cell<Option<BasicBlockRef>>,
326 // If the function has any nested return's, including something like:
327 // fn foo() -> Option<Foo> { Some(Foo { x: return None }) }, then
328 // we use a separate alloca for each return
329 pub needs_ret_allocas: bool,
331 // When working with landingpad-based exceptions this value is alloca'd and
332 // later loaded when using the resume instruction. This ends up being
333 // critical to chaining landing pads and resuing already-translated
336 // Note that for cleanuppad-based exceptions this is not used.
337 pub landingpad_alloca: Cell<Option<ValueRef>>,
339 // True if the caller expects this fn to use the out pointer to
340 // return. Either way, your code should write into the slot llretslotptr
341 // points to, but if this value is false, that slot will be a local alloca.
342 pub caller_expects_out_pointer: bool,
344 // Maps the DefId's for local variables to the allocas created for
345 // them in llallocas.
346 pub lllocals: RefCell<NodeMap<LvalueDatum<'tcx>>>,
348 // Same as above, but for closure upvars
349 pub llupvars: RefCell<NodeMap<ValueRef>>,
351 // Carries info about drop-flags for local bindings (longer term,
352 // paths) for the code being compiled.
353 pub lldropflag_hints: RefCell<DropFlagHintsMap<'tcx>>,
355 // The NodeId of the function, or -1 if it doesn't correspond to
356 // a user-defined function.
359 // If this function is being monomorphized, this contains the type
360 // substitutions used.
361 pub param_substs: &'tcx Substs<'tcx>,
363 // The source span and nesting context where this function comes from, for
364 // error reporting and symbol generation.
365 pub span: Option<Span>,
367 // The arena that blocks are allocated from.
368 pub block_arena: &'a TypedArena<BlockS<'a, 'tcx>>,
370 // The arena that landing pads are allocated from.
371 pub lpad_arena: TypedArena<LandingPad>,
373 // This function's enclosing crate context.
374 pub ccx: &'a CrateContext<'a, 'tcx>,
376 // Used and maintained by the debuginfo module.
377 pub debug_context: debuginfo::FunctionDebugContext,
380 pub scopes: RefCell<Vec<cleanup::CleanupScope<'a, 'tcx>>>,
382 pub cfg: Option<cfg::CFG>,
385 impl<'a, 'tcx> FunctionContext<'a, 'tcx> {
386 pub fn mir(&self) -> &'a Mir<'tcx> {
390 pub fn arg_offset(&self) -> usize {
391 self.env_arg_pos() + if self.llenv.is_some() { 1 } else { 0 }
394 pub fn env_arg_pos(&self) -> usize {
395 if self.caller_expects_out_pointer {
402 pub fn cleanup(&self) {
404 llvm::LLVMInstructionEraseFromParent(self.alloca_insert_pt
410 pub fn get_llreturn(&self) -> BasicBlockRef {
411 if self.llreturn.get().is_none() {
413 self.llreturn.set(Some(unsafe {
414 llvm::LLVMAppendBasicBlockInContext(self.ccx.llcx(), self.llfn,
415 "return\0".as_ptr() as *const _)
419 self.llreturn.get().unwrap()
422 pub fn get_ret_slot(&self, bcx: Block<'a, 'tcx>,
423 output: ty::FnOutput<'tcx>,
424 name: &str) -> ValueRef {
425 if self.needs_ret_allocas {
426 base::alloca(bcx, match output {
427 ty::FnConverging(output_type) => type_of::type_of(bcx.ccx(), output_type),
428 ty::FnDiverging => Type::void(bcx.ccx())
431 self.llretslotptr.get().unwrap()
435 pub fn new_block(&'a self,
437 opt_node_id: Option<ast::NodeId>)
440 let name = CString::new(name).unwrap();
441 let llbb = llvm::LLVMAppendBasicBlockInContext(self.ccx.llcx(),
444 BlockS::new(llbb, opt_node_id, self)
448 pub fn new_id_block(&'a self,
450 node_id: ast::NodeId)
452 self.new_block(name, Some(node_id))
455 pub fn new_temp_block(&'a self,
458 self.new_block(name, None)
461 pub fn join_blocks(&'a self,
463 in_cxs: &[Block<'a, 'tcx>])
465 let out = self.new_id_block("join", id);
466 let mut reachable = false;
468 if !bcx.unreachable.get() {
469 build::Br(*bcx, out.llbb, DebugLoc::None);
474 build::Unreachable(out);
479 pub fn monomorphize<T>(&self, value: &T) -> T
480 where T : TypeFoldable<'tcx>
482 monomorphize::apply_param_substs(self.ccx.tcx(),
487 /// This is the same as `common::type_needs_drop`, except that it
488 /// may use or update caches within this `FunctionContext`.
489 pub fn type_needs_drop(&self, ty: Ty<'tcx>) -> bool {
490 self.ccx.tcx().type_needs_drop_given_env(ty, &self.param_env)
493 pub fn eh_personality(&self) -> ValueRef {
494 // The exception handling personality function.
496 // If our compilation unit has the `eh_personality` lang item somewhere
497 // within it, then we just need to translate that. Otherwise, we're
498 // building an rlib which will depend on some upstream implementation of
499 // this function, so we just codegen a generic reference to it. We don't
500 // specify any of the types for the function, we just make it a symbol
501 // that LLVM can later use.
503 // Note that MSVC is a little special here in that we don't use the
504 // `eh_personality` lang item at all. Currently LLVM has support for
505 // both Dwarf and SEH unwind mechanisms for MSVC targets and uses the
506 // *name of the personality function* to decide what kind of unwind side
507 // tables/landing pads to emit. It looks like Dwarf is used by default,
508 // injecting a dependency on the `_Unwind_Resume` symbol for resuming
509 // an "exception", but for MSVC we want to force SEH. This means that we
510 // can't actually have the personality function be our standard
511 // `rust_eh_personality` function, but rather we wired it up to the
512 // CRT's custom personality function, which forces LLVM to consider
513 // landing pads as "landing pads for SEH".
514 let target = &self.ccx.sess().target.target;
515 match self.ccx.tcx().lang_items.eh_personality() {
516 Some(def_id) if !base::wants_msvc_seh(self.ccx.sess()) => {
517 callee::trans_fn_ref(self.ccx, def_id, ExprId(0),
518 self.param_substs).val
521 let mut personality = self.ccx.eh_personality().borrow_mut();
523 Some(llpersonality) => llpersonality,
525 let name = if !base::wants_msvc_seh(self.ccx.sess()) {
526 "rust_eh_personality"
527 } else if target.arch == "x86" {
530 "__C_specific_handler"
532 let fty = Type::variadic_func(&[], &Type::i32(self.ccx));
533 let f = declare::declare_cfn(self.ccx, name, fty,
534 self.ccx.tcx().types.i32);
535 *personality = Some(f);
543 // Returns a ValueRef of the "eh_unwind_resume" lang item if one is defined,
544 // otherwise declares it as an external function.
545 pub fn eh_unwind_resume(&self) -> ValueRef {
546 use trans::attributes;
547 assert!(self.ccx.sess().target.target.options.custom_unwind_resume);
548 match self.ccx.tcx().lang_items.eh_unwind_resume() {
550 callee::trans_fn_ref(self.ccx, def_id, ExprId(0),
551 self.param_substs).val
554 let mut unwresume = self.ccx.eh_unwind_resume().borrow_mut();
558 let fty = Type::func(&[Type::i8p(self.ccx)], &Type::void(self.ccx));
559 let llfn = declare::declare_fn(self.ccx,
560 "rust_eh_unwind_resume",
562 fty, ty::FnDiverging);
563 attributes::unwind(llfn, true);
564 *unwresume = Some(llfn);
573 // Basic block context. We create a block context for each basic block
574 // (single-entry, single-exit sequence of instructions) we generate from Rust
575 // code. Each basic block we generate is attached to a function, typically
576 // with many basic blocks per function. All the basic blocks attached to a
577 // function are organized as a directed graph.
578 pub struct BlockS<'blk, 'tcx: 'blk> {
579 // The BasicBlockRef returned from a call to
580 // llvm::LLVMAppendBasicBlock(llfn, name), which adds a basic
581 // block to the function pointed to by llfn. We insert
582 // instructions into that block by way of this block context.
583 // The block pointing to this one in the function's digraph.
584 pub llbb: BasicBlockRef,
585 pub terminated: Cell<bool>,
586 pub unreachable: Cell<bool>,
588 // If this block part of a landing pad, then this is `Some` indicating what
589 // kind of landing pad its in, otherwise this is none.
590 pub lpad: Cell<Option<&'blk LandingPad>>,
592 // AST node-id associated with this block, if any. Used for
593 // debugging purposes only.
594 pub opt_node_id: Option<ast::NodeId>,
596 // The function context for the function to which this block is
598 pub fcx: &'blk FunctionContext<'blk, 'tcx>,
601 pub type Block<'blk, 'tcx> = &'blk BlockS<'blk, 'tcx>;
603 impl<'blk, 'tcx> BlockS<'blk, 'tcx> {
604 pub fn new(llbb: BasicBlockRef,
605 opt_node_id: Option<ast::NodeId>,
606 fcx: &'blk FunctionContext<'blk, 'tcx>)
607 -> Block<'blk, 'tcx> {
608 fcx.block_arena.alloc(BlockS {
610 terminated: Cell::new(false),
611 unreachable: Cell::new(false),
612 lpad: Cell::new(None),
613 opt_node_id: opt_node_id,
618 pub fn ccx(&self) -> &'blk CrateContext<'blk, 'tcx> {
621 pub fn fcx(&self) -> &'blk FunctionContext<'blk, 'tcx> {
624 pub fn tcx(&self) -> &'blk ty::ctxt<'tcx> {
627 pub fn sess(&self) -> &'blk Session { self.fcx.ccx.sess() }
629 pub fn lpad(&self) -> Option<&'blk LandingPad> {
633 pub fn mir(&self) -> &'blk Mir<'tcx> {
637 pub fn name(&self, name: ast::Name) -> String {
641 pub fn node_id_to_string(&self, id: ast::NodeId) -> String {
642 self.tcx().map.node_to_string(id).to_string()
645 pub fn def(&self, nid: ast::NodeId) -> Def {
646 match self.tcx().def_map.borrow().get(&nid) {
647 Some(v) => v.full_def(),
649 self.tcx().sess.bug(&format!(
650 "no def associated with node id {}", nid));
655 pub fn val_to_string(&self, val: ValueRef) -> String {
656 self.ccx().tn().val_to_string(val)
659 pub fn llty_str(&self, ty: Type) -> String {
660 self.ccx().tn().type_to_string(ty)
663 pub fn to_str(&self) -> String {
664 format!("[block {:p}]", self)
667 pub fn monomorphize<T>(&self, value: &T) -> T
668 where T : TypeFoldable<'tcx>
670 monomorphize::apply_param_substs(self.tcx(),
671 self.fcx.param_substs,
675 pub fn build(&'blk self) -> BlockAndBuilder<'blk, 'tcx> {
676 BlockAndBuilder::new(self, OwnedBuilder::new_with_ccx(self.ccx()))
680 pub struct OwnedBuilder<'blk, 'tcx: 'blk> {
681 builder: Builder<'blk, 'tcx>
684 impl<'blk, 'tcx> OwnedBuilder<'blk, 'tcx> {
685 pub fn new_with_ccx(ccx: &'blk CrateContext<'blk, 'tcx>) -> Self {
686 // Create a fresh builder from the crate context.
687 let llbuilder = unsafe {
688 llvm::LLVMCreateBuilderInContext(ccx.llcx())
692 llbuilder: llbuilder,
699 impl<'blk, 'tcx> Drop for OwnedBuilder<'blk, 'tcx> {
702 llvm::LLVMDisposeBuilder(self.builder.llbuilder);
707 pub struct BlockAndBuilder<'blk, 'tcx: 'blk> {
708 bcx: Block<'blk, 'tcx>,
709 owned_builder: OwnedBuilder<'blk, 'tcx>,
712 impl<'blk, 'tcx> BlockAndBuilder<'blk, 'tcx> {
713 pub fn new(bcx: Block<'blk, 'tcx>, owned_builder: OwnedBuilder<'blk, 'tcx>) -> Self {
714 // Set the builder's position to this block's end.
715 owned_builder.builder.position_at_end(bcx.llbb);
718 owned_builder: owned_builder,
722 pub fn with_block<F, R>(&self, f: F) -> R
723 where F: FnOnce(Block<'blk, 'tcx>) -> R
725 let result = f(self.bcx);
726 self.position_at_end(self.bcx.llbb);
730 pub fn map_block<F>(self, f: F) -> Self
731 where F: FnOnce(Block<'blk, 'tcx>) -> Block<'blk, 'tcx>
733 let BlockAndBuilder { bcx, owned_builder } = self;
735 BlockAndBuilder::new(bcx, owned_builder)
738 // Methods delegated to bcx
740 pub fn ccx(&self) -> &'blk CrateContext<'blk, 'tcx> {
743 pub fn fcx(&self) -> &'blk FunctionContext<'blk, 'tcx> {
746 pub fn tcx(&self) -> &'blk ty::ctxt<'tcx> {
749 pub fn sess(&self) -> &'blk Session {
753 pub fn llbb(&self) -> BasicBlockRef {
757 pub fn mir(&self) -> &'blk Mir<'tcx> {
761 pub fn val_to_string(&self, val: ValueRef) -> String {
762 self.bcx.val_to_string(val)
765 pub fn monomorphize<T>(&self, value: &T) -> T
766 where T: TypeFoldable<'tcx>
768 self.bcx.monomorphize(value)
772 impl<'blk, 'tcx> Deref for BlockAndBuilder<'blk, 'tcx> {
773 type Target = Builder<'blk, 'tcx>;
774 fn deref(&self) -> &Self::Target {
775 &self.owned_builder.builder
779 /// A structure representing an active landing pad for the duration of a basic
782 /// Each `Block` may contain an instance of this, indicating whether the block
783 /// is part of a landing pad or not. This is used to make decision about whether
784 /// to emit `invoke` instructions (e.g. in a landing pad we don't continue to
785 /// use `invoke`) and also about various function call metadata.
787 /// For GNU exceptions (`landingpad` + `resume` instructions) this structure is
788 /// just a bunch of `None` instances (not too interesting), but for MSVC
789 /// exceptions (`cleanuppad` + `cleanupret` instructions) this contains data.
790 /// When inside of a landing pad, each function call in LLVM IR needs to be
791 /// annotated with which landing pad it's a part of. This is accomplished via
792 /// the `OperandBundleDef` value created for MSVC landing pads.
793 pub struct LandingPad {
794 cleanuppad: Option<ValueRef>,
795 operand: Option<OperandBundleDef>,
799 pub fn gnu() -> LandingPad {
800 LandingPad { cleanuppad: None, operand: None }
803 pub fn msvc(cleanuppad: ValueRef) -> LandingPad {
805 cleanuppad: Some(cleanuppad),
806 operand: Some(OperandBundleDef::new("funclet", &[cleanuppad])),
810 pub fn bundle(&self) -> Option<&OperandBundleDef> {
811 self.operand.as_ref()
815 impl Clone for LandingPad {
816 fn clone(&self) -> LandingPad {
818 cleanuppad: self.cleanuppad,
819 operand: self.cleanuppad.map(|p| {
820 OperandBundleDef::new("funclet", &[p])
826 pub struct Result<'blk, 'tcx: 'blk> {
827 pub bcx: Block<'blk, 'tcx>,
831 impl<'b, 'tcx> Result<'b, 'tcx> {
832 pub fn new(bcx: Block<'b, 'tcx>, val: ValueRef) -> Result<'b, 'tcx> {
840 pub fn val_ty(v: ValueRef) -> Type {
842 Type::from_ref(llvm::LLVMTypeOf(v))
846 // LLVM constant constructors.
847 pub fn C_null(t: Type) -> ValueRef {
849 llvm::LLVMConstNull(t.to_ref())
853 pub fn C_undef(t: Type) -> ValueRef {
855 llvm::LLVMGetUndef(t.to_ref())
859 pub fn C_integral(t: Type, u: u64, sign_extend: bool) -> ValueRef {
861 llvm::LLVMConstInt(t.to_ref(), u, sign_extend as Bool)
865 pub fn C_floating(s: &str, t: Type) -> ValueRef {
867 let s = CString::new(s).unwrap();
868 llvm::LLVMConstRealOfString(t.to_ref(), s.as_ptr())
872 pub fn C_floating_f64(f: f64, t: Type) -> ValueRef {
874 llvm::LLVMConstReal(t.to_ref(), f)
878 pub fn C_nil(ccx: &CrateContext) -> ValueRef {
879 C_struct(ccx, &[], false)
882 pub fn C_bool(ccx: &CrateContext, val: bool) -> ValueRef {
883 C_integral(Type::i1(ccx), val as u64, false)
886 pub fn C_i32(ccx: &CrateContext, i: i32) -> ValueRef {
887 C_integral(Type::i32(ccx), i as u64, true)
890 pub fn C_u32(ccx: &CrateContext, i: u32) -> ValueRef {
891 C_integral(Type::i32(ccx), i as u64, false)
894 pub fn C_u64(ccx: &CrateContext, i: u64) -> ValueRef {
895 C_integral(Type::i64(ccx), i, false)
898 pub fn C_int<I: AsI64>(ccx: &CrateContext, i: I) -> ValueRef {
901 let bit_size = machine::llbitsize_of_real(ccx, ccx.int_type());
904 // make sure it doesn't overflow
905 assert!(v < (1<<(bit_size-1)) && v >= -(1<<(bit_size-1)));
908 C_integral(ccx.int_type(), v as u64, true)
911 pub fn C_uint<I: AsU64>(ccx: &CrateContext, i: I) -> ValueRef {
914 let bit_size = machine::llbitsize_of_real(ccx, ccx.int_type());
917 // make sure it doesn't overflow
918 assert!(v < (1<<bit_size));
921 C_integral(ccx.int_type(), v, false)
924 pub trait AsI64 { fn as_i64(self) -> i64; }
925 pub trait AsU64 { fn as_u64(self) -> u64; }
927 // FIXME: remove the intptr conversions, because they
928 // are host-architecture-dependent
929 impl AsI64 for i64 { fn as_i64(self) -> i64 { self as i64 }}
930 impl AsI64 for i32 { fn as_i64(self) -> i64 { self as i64 }}
931 impl AsI64 for isize { fn as_i64(self) -> i64 { self as i64 }}
933 impl AsU64 for u64 { fn as_u64(self) -> u64 { self as u64 }}
934 impl AsU64 for u32 { fn as_u64(self) -> u64 { self as u64 }}
935 impl AsU64 for usize { fn as_u64(self) -> u64 { self as u64 }}
937 pub fn C_u8(ccx: &CrateContext, i: u8) -> ValueRef {
938 C_integral(Type::i8(ccx), i as u64, false)
942 // This is a 'c-like' raw string, which differs from
943 // our boxed-and-length-annotated strings.
944 pub fn C_cstr(cx: &CrateContext, s: InternedString, null_terminated: bool) -> ValueRef {
946 match cx.const_cstr_cache().borrow().get(&s) {
947 Some(&llval) => return llval,
951 let sc = llvm::LLVMConstStringInContext(cx.llcx(),
952 s.as_ptr() as *const c_char,
954 !null_terminated as Bool);
956 let gsym = token::gensym("str");
957 let sym = format!("str{}", gsym.0);
958 let g = declare::define_global(cx, &sym[..], val_ty(sc)).unwrap_or_else(||{
959 cx.sess().bug(&format!("symbol `{}` is already defined", sym));
961 llvm::LLVMSetInitializer(g, sc);
962 llvm::LLVMSetGlobalConstant(g, True);
963 llvm::SetLinkage(g, llvm::InternalLinkage);
965 cx.const_cstr_cache().borrow_mut().insert(s, g);
970 // NB: Do not use `do_spill_noroot` to make this into a constant string, or
971 // you will be kicked off fast isel. See issue #4352 for an example of this.
972 pub fn C_str_slice(cx: &CrateContext, s: InternedString) -> ValueRef {
974 let cs = consts::ptrcast(C_cstr(cx, s, false), Type::i8p(cx));
975 C_named_struct(cx.tn().find_type("str_slice").unwrap(), &[cs, C_uint(cx, len)])
978 pub fn C_struct(cx: &CrateContext, elts: &[ValueRef], packed: bool) -> ValueRef {
979 C_struct_in_context(cx.llcx(), elts, packed)
982 pub fn C_struct_in_context(llcx: ContextRef, elts: &[ValueRef], packed: bool) -> ValueRef {
984 llvm::LLVMConstStructInContext(llcx,
985 elts.as_ptr(), elts.len() as c_uint,
990 pub fn C_named_struct(t: Type, elts: &[ValueRef]) -> ValueRef {
992 llvm::LLVMConstNamedStruct(t.to_ref(), elts.as_ptr(), elts.len() as c_uint)
996 pub fn C_array(ty: Type, elts: &[ValueRef]) -> ValueRef {
998 return llvm::LLVMConstArray(ty.to_ref(), elts.as_ptr(), elts.len() as c_uint);
1002 pub fn C_vector(elts: &[ValueRef]) -> ValueRef {
1004 return llvm::LLVMConstVector(elts.as_ptr(), elts.len() as c_uint);
1008 pub fn C_bytes(cx: &CrateContext, bytes: &[u8]) -> ValueRef {
1009 C_bytes_in_context(cx.llcx(), bytes)
1012 pub fn C_bytes_in_context(llcx: ContextRef, bytes: &[u8]) -> ValueRef {
1014 let ptr = bytes.as_ptr() as *const c_char;
1015 return llvm::LLVMConstStringInContext(llcx, ptr, bytes.len() as c_uint, True);
1019 pub fn const_get_elt(cx: &CrateContext, v: ValueRef, us: &[c_uint])
1022 let r = llvm::LLVMConstExtractValue(v, us.as_ptr(), us.len() as c_uint);
1024 debug!("const_get_elt(v={}, us={:?}, r={})",
1025 cx.tn().val_to_string(v), us, cx.tn().val_to_string(r));
1031 pub fn const_to_int(v: ValueRef) -> i64 {
1033 llvm::LLVMConstIntGetSExtValue(v)
1037 pub fn const_to_uint(v: ValueRef) -> u64 {
1039 llvm::LLVMConstIntGetZExtValue(v)
1043 fn is_const_integral(v: ValueRef) -> bool {
1045 !llvm::LLVMIsAConstantInt(v).is_null()
1049 pub fn const_to_opt_int(v: ValueRef) -> Option<i64> {
1051 if is_const_integral(v) {
1052 Some(llvm::LLVMConstIntGetSExtValue(v))
1059 pub fn const_to_opt_uint(v: ValueRef) -> Option<u64> {
1061 if is_const_integral(v) {
1062 Some(llvm::LLVMConstIntGetZExtValue(v))
1069 pub fn is_undef(val: ValueRef) -> bool {
1071 llvm::LLVMIsUndef(val) != False
1075 #[allow(dead_code)] // potentially useful
1076 pub fn is_null(val: ValueRef) -> bool {
1078 llvm::LLVMIsNull(val) != False
1082 pub fn monomorphize_type<'blk, 'tcx>(bcx: &BlockS<'blk, 'tcx>, t: Ty<'tcx>) -> Ty<'tcx> {
1083 bcx.fcx.monomorphize(&t)
1086 pub fn node_id_type<'blk, 'tcx>(bcx: &BlockS<'blk, 'tcx>, id: ast::NodeId) -> Ty<'tcx> {
1087 let tcx = bcx.tcx();
1088 let t = tcx.node_id_to_type(id);
1089 monomorphize_type(bcx, t)
1092 pub fn expr_ty<'blk, 'tcx>(bcx: &BlockS<'blk, 'tcx>, ex: &hir::Expr) -> Ty<'tcx> {
1093 node_id_type(bcx, ex.id)
1096 pub fn expr_ty_adjusted<'blk, 'tcx>(bcx: &BlockS<'blk, 'tcx>, ex: &hir::Expr) -> Ty<'tcx> {
1097 monomorphize_type(bcx, bcx.tcx().expr_ty_adjusted(ex))
1100 /// Attempts to resolve an obligation. The result is a shallow vtable resolution -- meaning that we
1101 /// do not (necessarily) resolve all nested obligations on the impl. Note that type check should
1102 /// guarantee to us that all nested obligations *could be* resolved if we wanted to.
1103 pub fn fulfill_obligation<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
1105 trait_ref: ty::PolyTraitRef<'tcx>)
1106 -> traits::Vtable<'tcx, ()>
1108 let tcx = ccx.tcx();
1110 // Remove any references to regions; this helps improve caching.
1111 let trait_ref = tcx.erase_regions(&trait_ref);
1113 // First check the cache.
1114 match ccx.trait_cache().borrow().get(&trait_ref) {
1116 info!("Cache hit: {:?}", trait_ref);
1117 return (*vtable).clone();
1122 debug!("trans fulfill_obligation: trait_ref={:?} def_id={:?}",
1123 trait_ref, trait_ref.def_id());
1126 // Do the initial selection for the obligation. This yields the
1127 // shallow result we are looking for -- that is, what specific impl.
1128 let infcx = infer::normalizing_infer_ctxt(tcx, &tcx.tables);
1129 let mut selcx = traits::SelectionContext::new(&infcx);
1132 traits::Obligation::new(traits::ObligationCause::misc(span, ast::DUMMY_NODE_ID),
1133 trait_ref.to_poly_trait_predicate());
1134 let selection = match selcx.select(&obligation) {
1135 Ok(Some(selection)) => selection,
1137 // Ambiguity can happen when monomorphizing during trans
1138 // expands to some humongo type that never occurred
1139 // statically -- this humongo type can then overflow,
1140 // leading to an ambiguous result. So report this as an
1141 // overflow bug, since I believe this is the only case
1142 // where ambiguity can result.
1143 debug!("Encountered ambiguity selecting `{:?}` during trans, \
1144 presuming due to overflow",
1146 ccx.sess().span_fatal(
1148 "reached the recursion limit during monomorphization (selection ambiguity)");
1153 &format!("Encountered error `{:?}` selecting `{:?}` during trans",
1159 // Currently, we use a fulfillment context to completely resolve
1160 // all nested obligations. This is because they can inform the
1161 // inference of the impl's type parameters.
1162 let mut fulfill_cx = traits::FulfillmentContext::new();
1163 let vtable = selection.map(|predicate| {
1164 fulfill_cx.register_predicate_obligation(&infcx, predicate);
1166 let vtable = infer::drain_fulfillment_cx_or_panic(
1167 span, &infcx, &mut fulfill_cx, &vtable
1170 info!("Cache miss: {:?} => {:?}", trait_ref, vtable);
1172 ccx.trait_cache().borrow_mut().insert(trait_ref, vtable.clone());
1177 /// Normalizes the predicates and checks whether they hold. If this
1178 /// returns false, then either normalize encountered an error or one
1179 /// of the predicates did not hold. Used when creating vtables to
1180 /// check for unsatisfiable methods.
1181 pub fn normalize_and_test_predicates<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
1182 predicates: Vec<ty::Predicate<'tcx>>)
1185 debug!("normalize_and_test_predicates(predicates={:?})",
1188 let tcx = ccx.tcx();
1189 let infcx = infer::normalizing_infer_ctxt(tcx, &tcx.tables);
1190 let mut selcx = traits::SelectionContext::new(&infcx);
1191 let mut fulfill_cx = traits::FulfillmentContext::new();
1192 let cause = traits::ObligationCause::dummy();
1193 let traits::Normalized { value: predicates, obligations } =
1194 traits::normalize(&mut selcx, cause.clone(), &predicates);
1195 for obligation in obligations {
1196 fulfill_cx.register_predicate_obligation(&infcx, obligation);
1198 for predicate in predicates {
1199 let obligation = traits::Obligation::new(cause.clone(), predicate);
1200 fulfill_cx.register_predicate_obligation(&infcx, obligation);
1203 infer::drain_fulfillment_cx(&infcx, &mut fulfill_cx, &()).is_ok()
1206 // Key used to lookup values supplied for type parameters in an expr.
1207 #[derive(Copy, Clone, PartialEq, Debug)]
1208 pub enum ExprOrMethodCall {
1209 // Type parameters for a path like `None::<int>`
1210 ExprId(ast::NodeId),
1212 // Type parameters for a method call like `a.foo::<int>()`
1213 MethodCallKey(ty::MethodCall)
1216 pub fn node_id_substs<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
1217 node: ExprOrMethodCall,
1218 param_substs: &subst::Substs<'tcx>)
1219 -> subst::Substs<'tcx> {
1220 let tcx = ccx.tcx();
1222 let substs = match node {
1224 tcx.node_id_item_substs(id).substs
1226 MethodCallKey(method_call) => {
1227 tcx.tables.borrow().method_map[&method_call].substs.clone()
1231 if substs.types.needs_infer() {
1232 tcx.sess.bug(&format!("type parameters for node {:?} include inference types: {:?}",
1236 monomorphize::apply_param_substs(tcx,
1238 &substs.erase_regions())
1241 pub fn langcall(bcx: Block,
1246 match bcx.tcx().lang_items.require(li) {
1249 let msg = format!("{} {}", msg, s);
1251 Some(span) => bcx.tcx().sess.span_fatal(span, &msg[..]),
1252 None => bcx.tcx().sess.fatal(&msg[..]),
1258 /// Return the VariantDef corresponding to an inlined variant node
1259 pub fn inlined_variant_def<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
1260 inlined_vid: ast::NodeId)
1261 -> ty::VariantDef<'tcx>
1264 let ctor_ty = ccx.tcx().node_id_to_type(inlined_vid);
1265 debug!("inlined_variant_def: ctor_ty={:?} inlined_vid={:?}", ctor_ty,
1267 let adt_def = match ctor_ty.sty {
1268 ty::TyBareFn(_, &ty::BareFnTy { sig: ty::Binder(ty::FnSig {
1269 output: ty::FnConverging(ty), ..
1272 }.ty_adt_def().unwrap();
1273 let inlined_vid_def_id = ccx.tcx().map.local_def_id(inlined_vid);
1274 adt_def.variants.iter().find(|v| {
1275 inlined_vid_def_id == v.did ||
1276 ccx.external().borrow().get(&v.did) == Some(&Some(inlined_vid))
1277 }).unwrap_or_else(|| {
1278 ccx.sess().bug(&format!("no variant for {:?}::{}", adt_def, inlined_vid))
1282 // To avoid UB from LLVM, these two functions mask RHS with an
1283 // appropriate mask unconditionally (i.e. the fallback behavior for
1284 // all shifts). For 32- and 64-bit types, this matches the semantics
1285 // of Java. (See related discussion on #1877 and #10183.)
1287 pub fn build_unchecked_lshift<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1290 binop_debug_loc: DebugLoc) -> ValueRef {
1291 let rhs = base::cast_shift_expr_rhs(bcx, hir::BinOp_::BiShl, lhs, rhs);
1292 // #1877, #10183: Ensure that input is always valid
1293 let rhs = shift_mask_rhs(bcx, rhs, binop_debug_loc);
1294 build::Shl(bcx, lhs, rhs, binop_debug_loc)
1297 pub fn build_unchecked_rshift<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1301 binop_debug_loc: DebugLoc) -> ValueRef {
1302 let rhs = base::cast_shift_expr_rhs(bcx, hir::BinOp_::BiShr, lhs, rhs);
1303 // #1877, #10183: Ensure that input is always valid
1304 let rhs = shift_mask_rhs(bcx, rhs, binop_debug_loc);
1305 let is_signed = lhs_t.is_signed();
1307 build::AShr(bcx, lhs, rhs, binop_debug_loc)
1309 build::LShr(bcx, lhs, rhs, binop_debug_loc)
1313 fn shift_mask_rhs<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1315 debug_loc: DebugLoc) -> ValueRef {
1316 let rhs_llty = val_ty(rhs);
1317 build::And(bcx, rhs, shift_mask_val(bcx, rhs_llty, rhs_llty, false), debug_loc)
1320 pub fn shift_mask_val<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1323 invert: bool) -> ValueRef {
1324 let kind = llty.kind();
1326 TypeKind::Integer => {
1327 // i8/u8 can shift by at most 7, i16/u16 by at most 15, etc.
1328 let val = llty.int_width() - 1;
1330 C_integral(mask_llty, !val, true)
1332 C_integral(mask_llty, val, false)
1335 TypeKind::Vector => {
1336 let mask = shift_mask_val(bcx, llty.element_type(), mask_llty.element_type(), invert);
1337 build::VectorSplat(bcx, mask_llty.vector_length(), mask)
1339 _ => panic!("shift_mask_val: expected Integer or Vector, found {:?}", kind),
1343 pub fn get_static_val<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
1347 if let Some(node_id) = ccx.tcx().map.as_local_node_id(did) {
1348 base::get_item_val(ccx, node_id)
1350 base::get_extern_const(ccx, did, ty)