// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT // file at the top-level directory of this distribution and at // http://rust-lang.org/COPYRIGHT. // // Licensed under the Apache License, Version 2.0 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. //! Translate the completed AST to the LLVM IR. //! //! Some functions here, such as trans_block and trans_expr, return a value -- //! the result of the translation to LLVM -- while others, such as trans_fn, //! trans_impl, and trans_item, are called only for the side effect of adding a //! particular definition to the LLVM IR output we're producing. //! //! Hopefully useful general knowledge about trans: //! //! * There's no way to find out the Ty type of a ValueRef. Doing so //! would be "trying to get the eggs out of an omelette" (credit: //! pcwalton). You can, instead, find out its TypeRef by calling val_ty, //! but one TypeRef corresponds to many `Ty`s; for instance, tup(int, int, //! int) and rec(x=int, y=int, z=int) will have the same TypeRef. #![allow(non_camel_case_types)] pub use self::ValueOrigin::*; use super::CrateTranslation; use super::ModuleTranslation; use back::link::mangle_exported_name; use back::{link, abi}; use lint; use llvm::{BasicBlockRef, Linkage, ValueRef, Vector, get_param}; use llvm; use metadata::{csearch, encoder, loader}; use middle::astencode; use middle::cfg; use middle::lang_items::{LangItem, ExchangeMallocFnLangItem, StartFnLangItem}; use middle::weak_lang_items; use middle::subst::Substs; use middle::ty::{self, Ty, ClosureTyper, type_is_simd, simd_size}; use session::config::{self, NoDebugInfo}; use session::Session; use trans::_match; use trans::adt; use trans::attributes; use trans::build::*; use trans::builder::{Builder, noname}; use trans::callee; use trans::cleanup::CleanupMethods; use trans::cleanup; use trans::closure; use trans::common::{Block, C_bool, C_bytes_in_context, C_i32, C_int, C_integral}; use trans::common::{C_null, C_struct_in_context, C_u64, C_u8, C_undef}; use trans::common::{CrateContext, FunctionContext}; use trans::common::{Result, NodeIdAndSpan}; use trans::common::{node_id_type, return_type_is_void}; use trans::common::{type_is_immediate, type_is_zero_size, val_ty}; use trans::common; use trans::consts; use trans::context::SharedCrateContext; use trans::controlflow; use trans::datum; use trans::debuginfo::{self, DebugLoc, ToDebugLoc}; use trans::declare; use trans::expr; use trans::foreign; use trans::glue; use trans::intrinsic; use trans::machine; use trans::machine::{llsize_of, llsize_of_real}; use trans::meth; use trans::monomorphize; use trans::tvec; use trans::type_::Type; use trans::type_of; use trans::type_of::*; use trans::value::Value; use util::common::indenter; use util::ppaux::{Repr, ty_to_string}; use util::sha2::Sha256; use util::nodemap::NodeMap; use arena::TypedArena; use libc::c_uint; use std::ffi::{CStr, CString}; use std::cell::{Cell, RefCell}; use std::collections::HashSet; use std::mem; use std::str; use std::{i8, i16, i32, i64}; use syntax::abi::{Rust, RustCall, RustIntrinsic, Abi}; use syntax::ast_util::local_def; use syntax::attr::AttrMetaMethods; use syntax::attr; use syntax::codemap::Span; use syntax::parse::token::InternedString; use syntax::visit::Visitor; use syntax::visit; use syntax::{ast, ast_util, ast_map}; thread_local! { static TASK_LOCAL_INSN_KEY: RefCell>> = { RefCell::new(None) } } pub fn with_insn_ctxt(blk: F) where F: FnOnce(&[&'static str]), { TASK_LOCAL_INSN_KEY.with(move |slot| { slot.borrow().as_ref().map(move |s| blk(s)); }) } pub fn init_insn_ctxt() { TASK_LOCAL_INSN_KEY.with(|slot| { *slot.borrow_mut() = Some(Vec::new()); }); } pub struct _InsnCtxt { _cannot_construct_outside_of_this_module: () } impl Drop for _InsnCtxt { fn drop(&mut self) { TASK_LOCAL_INSN_KEY.with(|slot| { match slot.borrow_mut().as_mut() { Some(ctx) => { ctx.pop(); } None => {} } }) } } pub fn push_ctxt(s: &'static str) -> _InsnCtxt { debug!("new InsnCtxt: {}", s); TASK_LOCAL_INSN_KEY.with(|slot| { match slot.borrow_mut().as_mut() { Some(ctx) => ctx.push(s), None => {} } }); _InsnCtxt { _cannot_construct_outside_of_this_module: () } } pub struct StatRecorder<'a, 'tcx: 'a> { ccx: &'a CrateContext<'a, 'tcx>, name: Option, istart: usize, } impl<'a, 'tcx> StatRecorder<'a, 'tcx> { pub fn new(ccx: &'a CrateContext<'a, 'tcx>, name: String) -> StatRecorder<'a, 'tcx> { let istart = ccx.stats().n_llvm_insns.get(); StatRecorder { ccx: ccx, name: Some(name), istart: istart, } } } impl<'a, 'tcx> Drop for StatRecorder<'a, 'tcx> { fn drop(&mut self) { if self.ccx.sess().trans_stats() { let iend = self.ccx.stats().n_llvm_insns.get(); self.ccx.stats().fn_stats.borrow_mut().push((self.name.take().unwrap(), iend - self.istart)); self.ccx.stats().n_fns.set(self.ccx.stats().n_fns.get() + 1); // Reset LLVM insn count to avoid compound costs. self.ccx.stats().n_llvm_insns.set(self.istart); } } } fn get_extern_rust_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, fn_ty: Ty<'tcx>, name: &str, did: ast::DefId) -> ValueRef { match ccx.externs().borrow().get(name) { Some(n) => return *n, None => () } let f = declare::declare_rust_fn(ccx, name, fn_ty); let attrs = csearch::get_item_attrs(&ccx.sess().cstore, did); attributes::from_fn_attrs(ccx, &attrs[..], f); ccx.externs().borrow_mut().insert(name.to_string(), f); f } pub fn self_type_for_closure<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, closure_id: ast::DefId, fn_ty: Ty<'tcx>) -> Ty<'tcx> { let closure_kind = ccx.tcx().closure_kind(closure_id); match closure_kind { ty::FnClosureKind => { ty::mk_imm_rptr(ccx.tcx(), ccx.tcx().mk_region(ty::ReStatic), fn_ty) } ty::FnMutClosureKind => { ty::mk_mut_rptr(ccx.tcx(), ccx.tcx().mk_region(ty::ReStatic), fn_ty) } ty::FnOnceClosureKind => fn_ty } } pub fn kind_for_closure(ccx: &CrateContext, closure_id: ast::DefId) -> ty::ClosureKind { *ccx.tcx().closure_kinds.borrow().get(&closure_id).unwrap() } pub fn get_extern_const<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, did: ast::DefId, t: Ty<'tcx>) -> ValueRef { let name = csearch::get_symbol(&ccx.sess().cstore, did); let ty = type_of(ccx, t); match ccx.externs().borrow_mut().get(&name) { Some(n) => return *n, None => () } // FIXME(nagisa): perhaps the map of externs could be offloaded to llvm somehow? // FIXME(nagisa): investigate whether it can be changed into define_global let c = declare::declare_global(ccx, &name[..], ty); // Thread-local statics in some other crate need to *always* be linked // against in a thread-local fashion, so we need to be sure to apply the // thread-local attribute locally if it was present remotely. If we // don't do this then linker errors can be generated where the linker // complains that one object files has a thread local version of the // symbol and another one doesn't. for attr in &*ty::get_attrs(ccx.tcx(), did) { if attr.check_name("thread_local") { llvm::set_thread_local(c, true); } } ccx.externs().borrow_mut().insert(name.to_string(), c); return c; } fn require_alloc_fn<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, info_ty: Ty<'tcx>, it: LangItem) -> ast::DefId { match bcx.tcx().lang_items.require(it) { Ok(id) => id, Err(s) => { bcx.sess().fatal(&format!("allocation of `{}` {}", bcx.ty_to_string(info_ty), s)); } } } // The following malloc_raw_dyn* functions allocate a box to contain // a given type, but with a potentially dynamic size. pub fn malloc_raw_dyn<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, llty_ptr: Type, info_ty: Ty<'tcx>, size: ValueRef, align: ValueRef, debug_loc: DebugLoc) -> Result<'blk, 'tcx> { let _icx = push_ctxt("malloc_raw_exchange"); // Allocate space: let r = callee::trans_lang_call(bcx, require_alloc_fn(bcx, info_ty, ExchangeMallocFnLangItem), &[size, align], None, debug_loc); Result::new(r.bcx, PointerCast(r.bcx, r.val, llty_ptr)) } pub fn bin_op_to_icmp_predicate(ccx: &CrateContext, op: ast::BinOp_, signed: bool) -> llvm::IntPredicate { match op { ast::BiEq => llvm::IntEQ, ast::BiNe => llvm::IntNE, ast::BiLt => if signed { llvm::IntSLT } else { llvm::IntULT }, ast::BiLe => if signed { llvm::IntSLE } else { llvm::IntULE }, ast::BiGt => if signed { llvm::IntSGT } else { llvm::IntUGT }, ast::BiGe => if signed { llvm::IntSGE } else { llvm::IntUGE }, op => { ccx.sess().bug(&format!("comparison_op_to_icmp_predicate: expected \ comparison operator, found {:?}", op)); } } } pub fn bin_op_to_fcmp_predicate(ccx: &CrateContext, op: ast::BinOp_) -> llvm::RealPredicate { match op { ast::BiEq => llvm::RealOEQ, ast::BiNe => llvm::RealUNE, ast::BiLt => llvm::RealOLT, ast::BiLe => llvm::RealOLE, ast::BiGt => llvm::RealOGT, ast::BiGe => llvm::RealOGE, op => { ccx.sess().bug(&format!("comparison_op_to_fcmp_predicate: expected \ comparison operator, found {:?}", op)); } } } pub fn compare_scalar_types<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, lhs: ValueRef, rhs: ValueRef, t: Ty<'tcx>, op: ast::BinOp_, debug_loc: DebugLoc) -> ValueRef { match t.sty { ty::ty_tup(ref tys) if tys.is_empty() => { // We don't need to do actual comparisons for nil. // () == () holds but () < () does not. match op { ast::BiEq | ast::BiLe | ast::BiGe => return C_bool(bcx.ccx(), true), ast::BiNe | ast::BiLt | ast::BiGt => return C_bool(bcx.ccx(), false), // refinements would be nice _ => bcx.sess().bug("compare_scalar_types: must be a comparison operator") } } ty::ty_bare_fn(..) | ty::ty_bool | ty::ty_uint(_) | ty::ty_char => { ICmp(bcx, bin_op_to_icmp_predicate(bcx.ccx(), op, false), lhs, rhs, debug_loc) } ty::ty_ptr(mt) if common::type_is_sized(bcx.tcx(), mt.ty) => { ICmp(bcx, bin_op_to_icmp_predicate(bcx.ccx(), op, false), lhs, rhs, debug_loc) } ty::ty_int(_) => { ICmp(bcx, bin_op_to_icmp_predicate(bcx.ccx(), op, true), lhs, rhs, debug_loc) } ty::ty_float(_) => { FCmp(bcx, bin_op_to_fcmp_predicate(bcx.ccx(), op), lhs, rhs, debug_loc) } // Should never get here, because t is scalar. _ => bcx.sess().bug("non-scalar type passed to compare_scalar_types") } } pub fn compare_simd_types<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, lhs: ValueRef, rhs: ValueRef, t: Ty<'tcx>, op: ast::BinOp_, debug_loc: DebugLoc) -> ValueRef { let signed = match t.sty { ty::ty_float(_) => { // The comparison operators for floating point vectors are challenging. // LLVM outputs a `< size x i1 >`, but if we perform a sign extension // then bitcast to a floating point vector, the result will be `-NaN` // for each truth value. Because of this they are unsupported. bcx.sess().bug("compare_simd_types: comparison operators \ not supported for floating point SIMD types") }, ty::ty_uint(_) => false, ty::ty_int(_) => true, _ => bcx.sess().bug("compare_simd_types: invalid SIMD type"), }; let cmp = bin_op_to_icmp_predicate(bcx.ccx(), op, signed); // LLVM outputs an `< size x i1 >`, so we need to perform a sign extension // to get the correctly sized type. This will compile to a single instruction // once the IR is converted to assembly if the SIMD instruction is supported // by the target architecture. SExt(bcx, ICmp(bcx, cmp, lhs, rhs, debug_loc), val_ty(lhs)) } // Iterates through the elements of a structural type. pub fn iter_structural_ty<'blk, 'tcx, F>(cx: Block<'blk, 'tcx>, av: ValueRef, t: Ty<'tcx>, mut f: F) -> Block<'blk, 'tcx> where F: FnMut(Block<'blk, 'tcx>, ValueRef, Ty<'tcx>) -> Block<'blk, 'tcx>, { let _icx = push_ctxt("iter_structural_ty"); fn iter_variant<'blk, 'tcx, F>(cx: Block<'blk, 'tcx>, repr: &adt::Repr<'tcx>, av: ValueRef, variant: &ty::VariantInfo<'tcx>, substs: &Substs<'tcx>, f: &mut F) -> Block<'blk, 'tcx> where F: FnMut(Block<'blk, 'tcx>, ValueRef, Ty<'tcx>) -> Block<'blk, 'tcx>, { let _icx = push_ctxt("iter_variant"); let tcx = cx.tcx(); let mut cx = cx; for (i, &arg) in variant.args.iter().enumerate() { let arg = monomorphize::apply_param_substs(tcx, substs, &arg); cx = f(cx, adt::trans_field_ptr(cx, repr, av, variant.disr_val, i), arg); } return cx; } let (data_ptr, info) = if common::type_is_sized(cx.tcx(), t) { (av, None) } else { let data = GEPi(cx, av, &[0, abi::FAT_PTR_ADDR]); let info = GEPi(cx, av, &[0, abi::FAT_PTR_EXTRA]); (Load(cx, data), Some(Load(cx, info))) }; let mut cx = cx; match t.sty { ty::ty_struct(..) => { let repr = adt::represent_type(cx.ccx(), t); expr::with_field_tys(cx.tcx(), t, None, |discr, field_tys| { for (i, field_ty) in field_tys.iter().enumerate() { let field_ty = field_ty.mt.ty; let llfld_a = adt::trans_field_ptr(cx, &*repr, data_ptr, discr, i); let val = if common::type_is_sized(cx.tcx(), field_ty) { llfld_a } else { let scratch = datum::rvalue_scratch_datum(cx, field_ty, "__fat_ptr_iter"); Store(cx, llfld_a, GEPi(cx, scratch.val, &[0, abi::FAT_PTR_ADDR])); Store(cx, info.unwrap(), GEPi(cx, scratch.val, &[0, abi::FAT_PTR_EXTRA])); scratch.val }; cx = f(cx, val, field_ty); } }) } ty::ty_closure(def_id, substs) => { let repr = adt::represent_type(cx.ccx(), t); let typer = common::NormalizingClosureTyper::new(cx.tcx()); let upvars = typer.closure_upvars(def_id, substs).unwrap(); for (i, upvar) in upvars.iter().enumerate() { let llupvar = adt::trans_field_ptr(cx, &*repr, data_ptr, 0, i); cx = f(cx, llupvar, upvar.ty); } } ty::ty_vec(_, Some(n)) => { let (base, len) = tvec::get_fixed_base_and_len(cx, data_ptr, n); let unit_ty = ty::sequence_element_type(cx.tcx(), t); cx = tvec::iter_vec_raw(cx, base, unit_ty, len, f); } ty::ty_vec(_, None) | ty::ty_str => { let unit_ty = ty::sequence_element_type(cx.tcx(), t); cx = tvec::iter_vec_raw(cx, data_ptr, unit_ty, info.unwrap(), f); } ty::ty_tup(ref args) => { let repr = adt::represent_type(cx.ccx(), t); for (i, arg) in args.iter().enumerate() { let llfld_a = adt::trans_field_ptr(cx, &*repr, data_ptr, 0, i); cx = f(cx, llfld_a, *arg); } } ty::ty_enum(tid, substs) => { let fcx = cx.fcx; let ccx = fcx.ccx; let repr = adt::represent_type(ccx, t); let variants = ty::enum_variants(ccx.tcx(), tid); let n_variants = (*variants).len(); // NB: we must hit the discriminant first so that structural // comparison know not to proceed when the discriminants differ. match adt::trans_switch(cx, &*repr, av) { (_match::Single, None) => { if n_variants != 0 { assert!(n_variants == 1); cx = iter_variant(cx, &*repr, av, &*(*variants)[0], substs, &mut f); } } (_match::Switch, Some(lldiscrim_a)) => { cx = f(cx, lldiscrim_a, cx.tcx().types.isize); let unr_cx = fcx.new_temp_block("enum-iter-unr"); Unreachable(unr_cx); let llswitch = Switch(cx, lldiscrim_a, unr_cx.llbb, n_variants); let next_cx = fcx.new_temp_block("enum-iter-next"); for variant in &(*variants) { let variant_cx = fcx.new_temp_block( &format!("enum-iter-variant-{}", &variant.disr_val.to_string()) ); match adt::trans_case(cx, &*repr, variant.disr_val) { _match::SingleResult(r) => { AddCase(llswitch, r.val, variant_cx.llbb) } _ => ccx.sess().unimpl("value from adt::trans_case \ in iter_structural_ty") } let variant_cx = iter_variant(variant_cx, &*repr, data_ptr, &**variant, substs, &mut f); Br(variant_cx, next_cx.llbb, DebugLoc::None); } cx = next_cx; } _ => ccx.sess().unimpl("value from adt::trans_switch \ in iter_structural_ty") } } _ => { cx.sess().unimpl(&format!("type in iter_structural_ty: {}", ty_to_string(cx.tcx(), t))) } } return cx; } pub fn cast_shift_expr_rhs(cx: Block, op: ast::BinOp_, lhs: ValueRef, rhs: ValueRef) -> ValueRef { cast_shift_rhs(op, lhs, rhs, |a,b| Trunc(cx, a, b), |a,b| ZExt(cx, a, b)) } pub fn cast_shift_const_rhs(op: ast::BinOp_, lhs: ValueRef, rhs: ValueRef) -> ValueRef { cast_shift_rhs(op, lhs, rhs, |a, b| unsafe { llvm::LLVMConstTrunc(a, b.to_ref()) }, |a, b| unsafe { llvm::LLVMConstZExt(a, b.to_ref()) }) } fn cast_shift_rhs(op: ast::BinOp_, lhs: ValueRef, rhs: ValueRef, trunc: F, zext: G) -> ValueRef where F: FnOnce(ValueRef, Type) -> ValueRef, G: FnOnce(ValueRef, Type) -> ValueRef, { // Shifts may have any size int on the rhs if ast_util::is_shift_binop(op) { let mut rhs_llty = val_ty(rhs); let mut lhs_llty = val_ty(lhs); if rhs_llty.kind() == Vector { rhs_llty = rhs_llty.element_type() } if lhs_llty.kind() == Vector { lhs_llty = lhs_llty.element_type() } let rhs_sz = rhs_llty.int_width(); let lhs_sz = lhs_llty.int_width(); if lhs_sz < rhs_sz { trunc(rhs, lhs_llty) } else if lhs_sz > rhs_sz { // FIXME (#1877: If shifting by negative // values becomes not undefined then this is wrong. zext(rhs, lhs_llty) } else { rhs } } else { rhs } } pub fn llty_and_min_for_signed_ty<'blk, 'tcx>(cx: Block<'blk, 'tcx>, val_t: Ty<'tcx>) -> (Type, u64) { match val_t.sty { ty::ty_int(t) => { let llty = Type::int_from_ty(cx.ccx(), t); let min = match t { ast::TyIs if llty == Type::i32(cx.ccx()) => i32::MIN as u64, ast::TyIs => i64::MIN as u64, ast::TyI8 => i8::MIN as u64, ast::TyI16 => i16::MIN as u64, ast::TyI32 => i32::MIN as u64, ast::TyI64 => i64::MIN as u64, }; (llty, min) } _ => unreachable!(), } } pub fn fail_if_zero_or_overflows<'blk, 'tcx>( cx: Block<'blk, 'tcx>, call_info: NodeIdAndSpan, divrem: ast::BinOp, lhs: ValueRef, rhs: ValueRef, rhs_t: Ty<'tcx>) -> Block<'blk, 'tcx> { let (zero_text, overflow_text) = if divrem.node == ast::BiDiv { ("attempted to divide by zero", "attempted to divide with overflow") } else { ("attempted remainder with a divisor of zero", "attempted remainder with overflow") }; let debug_loc = call_info.debug_loc(); let (is_zero, is_signed) = match rhs_t.sty { ty::ty_int(t) => { let zero = C_integral(Type::int_from_ty(cx.ccx(), t), 0, false); (ICmp(cx, llvm::IntEQ, rhs, zero, debug_loc), true) } ty::ty_uint(t) => { let zero = C_integral(Type::uint_from_ty(cx.ccx(), t), 0, false); (ICmp(cx, llvm::IntEQ, rhs, zero, debug_loc), false) } ty::ty_struct(_, _) if type_is_simd(cx.tcx(), rhs_t) => { let mut res = C_bool(cx.ccx(), false); for i in 0 .. simd_size(cx.tcx(), rhs_t) { res = Or(cx, res, IsNull(cx, ExtractElement(cx, rhs, C_int(cx.ccx(), i as i64))), debug_loc); } (res, false) } _ => { cx.sess().bug(&format!("fail-if-zero on unexpected type: {}", ty_to_string(cx.tcx(), rhs_t))); } }; let bcx = with_cond(cx, is_zero, |bcx| { controlflow::trans_fail(bcx, call_info, InternedString::new(zero_text)) }); // To quote LLVM's documentation for the sdiv instruction: // // Division by zero leads to undefined behavior. Overflow also leads // to undefined behavior; this is a rare case, but can occur, for // example, by doing a 32-bit division of -2147483648 by -1. // // In order to avoid undefined behavior, we perform runtime checks for // signed division/remainder which would trigger overflow. For unsigned // integers, no action beyond checking for zero need be taken. if is_signed { let (llty, min) = llty_and_min_for_signed_ty(cx, rhs_t); let minus_one = ICmp(bcx, llvm::IntEQ, rhs, C_integral(llty, !0, false), debug_loc); with_cond(bcx, minus_one, |bcx| { let is_min = ICmp(bcx, llvm::IntEQ, lhs, C_integral(llty, min, true), debug_loc); with_cond(bcx, is_min, |bcx| { controlflow::trans_fail(bcx, call_info, InternedString::new(overflow_text)) }) }) } else { bcx } } pub fn trans_external_path<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, did: ast::DefId, t: Ty<'tcx>) -> ValueRef { let name = csearch::get_symbol(&ccx.sess().cstore, did); match t.sty { ty::ty_bare_fn(_, ref fn_ty) => { match ccx.sess().target.target.adjust_abi(fn_ty.abi) { Rust | RustCall => { get_extern_rust_fn(ccx, t, &name[..], did) } RustIntrinsic => { ccx.sess().bug("unexpected intrinsic in trans_external_path") } _ => { let llfn = foreign::register_foreign_item_fn(ccx, fn_ty.abi, t, &name[..]); let attrs = csearch::get_item_attrs(&ccx.sess().cstore, did); attributes::from_fn_attrs(ccx, &attrs, llfn); llfn } } } _ => { get_extern_const(ccx, did, t) } } } pub fn invoke<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, llfn: ValueRef, llargs: &[ValueRef], fn_ty: Ty<'tcx>, debug_loc: DebugLoc) -> (ValueRef, Block<'blk, 'tcx>) { let _icx = push_ctxt("invoke_"); if bcx.unreachable.get() { return (C_null(Type::i8(bcx.ccx())), bcx); } let attributes = attributes::from_fn_type(bcx.ccx(), fn_ty); match bcx.opt_node_id { None => { debug!("invoke at ???"); } Some(id) => { debug!("invoke at {}", bcx.tcx().map.node_to_string(id)); } } if need_invoke(bcx) { debug!("invoking {} at {:?}", bcx.val_to_string(llfn), bcx.llbb); for &llarg in llargs { debug!("arg: {}", bcx.val_to_string(llarg)); } let normal_bcx = bcx.fcx.new_temp_block("normal-return"); let landing_pad = bcx.fcx.get_landing_pad(); let llresult = Invoke(bcx, llfn, &llargs[..], normal_bcx.llbb, landing_pad, Some(attributes), debug_loc); return (llresult, normal_bcx); } else { debug!("calling {} at {:?}", bcx.val_to_string(llfn), bcx.llbb); for &llarg in llargs { debug!("arg: {}", bcx.val_to_string(llarg)); } let llresult = Call(bcx, llfn, &llargs[..], Some(attributes), debug_loc); return (llresult, bcx); } } pub fn need_invoke(bcx: Block) -> bool { if bcx.sess().no_landing_pads() { return false; } // Avoid using invoke if we are already inside a landing pad. if bcx.is_lpad { return false; } bcx.fcx.needs_invoke() } pub fn load_if_immediate<'blk, 'tcx>(cx: Block<'blk, 'tcx>, v: ValueRef, t: Ty<'tcx>) -> ValueRef { let _icx = push_ctxt("load_if_immediate"); if type_is_immediate(cx.ccx(), t) { return load_ty(cx, v, t); } return v; } /// Helper for loading values from memory. Does the necessary conversion if the in-memory type /// differs from the type used for SSA values. Also handles various special cases where the type /// gives us better information about what we are loading. pub fn load_ty<'blk, 'tcx>(cx: Block<'blk, 'tcx>, ptr: ValueRef, t: Ty<'tcx>) -> ValueRef { if cx.unreachable.get() || type_is_zero_size(cx.ccx(), t) { return C_undef(type_of::type_of(cx.ccx(), t)); } let ptr = to_arg_ty_ptr(cx, ptr, t); let align = type_of::align_of(cx.ccx(), t); if type_is_immediate(cx.ccx(), t) && type_of::type_of(cx.ccx(), t).is_aggregate() { let load = Load(cx, ptr); unsafe { llvm::LLVMSetAlignment(load, align); } return load; } unsafe { let global = llvm::LLVMIsAGlobalVariable(ptr); if !global.is_null() && llvm::LLVMIsGlobalConstant(global) == llvm::True { let val = llvm::LLVMGetInitializer(global); if !val.is_null() { return from_arg_ty(cx, val, t); } } } let val = if ty::type_is_bool(t) { LoadRangeAssert(cx, ptr, 0, 2, llvm::False) } else if ty::type_is_char(t) { // a char is a Unicode codepoint, and so takes values from 0 // to 0x10FFFF inclusive only. LoadRangeAssert(cx, ptr, 0, 0x10FFFF + 1, llvm::False) } else if (ty::type_is_region_ptr(t) || ty::type_is_unique(t)) && !common::type_is_fat_ptr(cx.tcx(), t) { LoadNonNull(cx, ptr) } else { Load(cx, ptr) }; unsafe { llvm::LLVMSetAlignment(val, align); } from_arg_ty(cx, val, t) } /// Helper for storing values in memory. Does the necessary conversion if the in-memory type /// differs from the type used for SSA values. pub fn store_ty<'blk, 'tcx>(cx: Block<'blk, 'tcx>, v: ValueRef, dst: ValueRef, t: Ty<'tcx>) { if cx.unreachable.get() { return; } let store = Store(cx, to_arg_ty(cx, v, t), to_arg_ty_ptr(cx, dst, t)); unsafe { llvm::LLVMSetAlignment(store, type_of::align_of(cx.ccx(), t)); } } pub fn to_arg_ty(bcx: Block, val: ValueRef, ty: Ty) -> ValueRef { if ty::type_is_bool(ty) { ZExt(bcx, val, Type::i8(bcx.ccx())) } else { val } } pub fn from_arg_ty(bcx: Block, val: ValueRef, ty: Ty) -> ValueRef { if ty::type_is_bool(ty) { Trunc(bcx, val, Type::i1(bcx.ccx())) } else { val } } pub fn to_arg_ty_ptr<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, ptr: ValueRef, ty: Ty<'tcx>) -> ValueRef { if type_is_immediate(bcx.ccx(), ty) && type_of::type_of(bcx.ccx(), ty).is_aggregate() { // We want to pass small aggregates as immediate values, but using an aggregate LLVM type // for this leads to bad optimizations, so its arg type is an appropriately sized integer // and we have to convert it BitCast(bcx, ptr, type_of::arg_type_of(bcx.ccx(), ty).ptr_to()) } else { ptr } } pub fn init_local<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, local: &ast::Local) -> Block<'blk, 'tcx> { debug!("init_local(bcx={}, local.id={})", bcx.to_str(), local.id); let _indenter = indenter(); let _icx = push_ctxt("init_local"); _match::store_local(bcx, local) } pub fn raw_block<'blk, 'tcx>(fcx: &'blk FunctionContext<'blk, 'tcx>, is_lpad: bool, llbb: BasicBlockRef) -> Block<'blk, 'tcx> { common::BlockS::new(llbb, is_lpad, None, fcx) } pub fn with_cond<'blk, 'tcx, F>(bcx: Block<'blk, 'tcx>, val: ValueRef, f: F) -> Block<'blk, 'tcx> where F: FnOnce(Block<'blk, 'tcx>) -> Block<'blk, 'tcx>, { let _icx = push_ctxt("with_cond"); if bcx.unreachable.get() || (common::is_const(val) && common::const_to_uint(val) == 0) { return bcx; } let fcx = bcx.fcx; let next_cx = fcx.new_temp_block("next"); let cond_cx = fcx.new_temp_block("cond"); CondBr(bcx, val, cond_cx.llbb, next_cx.llbb, DebugLoc::None); let after_cx = f(cond_cx); if !after_cx.terminated.get() { Br(after_cx, next_cx.llbb, DebugLoc::None); } next_cx } pub fn call_lifetime_start(cx: Block, ptr: ValueRef) { if cx.sess().opts.optimize == config::No { return; } let _icx = push_ctxt("lifetime_start"); let ccx = cx.ccx(); let llsize = C_u64(ccx, machine::llsize_of_alloc(ccx, val_ty(ptr).element_type())); let ptr = PointerCast(cx, ptr, Type::i8p(ccx)); let lifetime_start = ccx.get_intrinsic(&"llvm.lifetime.start"); Call(cx, lifetime_start, &[llsize, ptr], None, DebugLoc::None); } pub fn call_lifetime_end(cx: Block, ptr: ValueRef) { if cx.sess().opts.optimize == config::No { return; } let _icx = push_ctxt("lifetime_end"); let ccx = cx.ccx(); let llsize = C_u64(ccx, machine::llsize_of_alloc(ccx, val_ty(ptr).element_type())); let ptr = PointerCast(cx, ptr, Type::i8p(ccx)); let lifetime_end = ccx.get_intrinsic(&"llvm.lifetime.end"); Call(cx, lifetime_end, &[llsize, ptr], None, DebugLoc::None); } pub fn call_memcpy(cx: Block, dst: ValueRef, src: ValueRef, n_bytes: ValueRef, align: u32) { let _icx = push_ctxt("call_memcpy"); let ccx = cx.ccx(); let key = match &ccx.sess().target.target.target_pointer_width[..] { "32" => "llvm.memcpy.p0i8.p0i8.i32", "64" => "llvm.memcpy.p0i8.p0i8.i64", tws => panic!("Unsupported target word size for memcpy: {}", tws), }; let memcpy = ccx.get_intrinsic(&key); let src_ptr = PointerCast(cx, src, Type::i8p(ccx)); let dst_ptr = PointerCast(cx, dst, Type::i8p(ccx)); let size = IntCast(cx, n_bytes, ccx.int_type()); let align = C_i32(ccx, align as i32); let volatile = C_bool(ccx, false); Call(cx, memcpy, &[dst_ptr, src_ptr, size, align, volatile], None, DebugLoc::None); } pub fn memcpy_ty<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, dst: ValueRef, src: ValueRef, t: Ty<'tcx>) { let _icx = push_ctxt("memcpy_ty"); let ccx = bcx.ccx(); if ty::type_is_structural(t) { let llty = type_of::type_of(ccx, t); let llsz = llsize_of(ccx, llty); let llalign = type_of::align_of(ccx, t); call_memcpy(bcx, dst, src, llsz, llalign as u32); } else { store_ty(bcx, load_ty(bcx, src, t), dst, t); } } pub fn drop_done_fill_mem<'blk, 'tcx>(cx: Block<'blk, 'tcx>, llptr: ValueRef, t: Ty<'tcx>) { if cx.unreachable.get() { return; } let _icx = push_ctxt("drop_done_fill_mem"); let bcx = cx; memfill(&B(bcx), llptr, t, adt::DTOR_DONE); } pub fn init_zero_mem<'blk, 'tcx>(cx: Block<'blk, 'tcx>, llptr: ValueRef, t: Ty<'tcx>) { if cx.unreachable.get() { return; } let _icx = push_ctxt("init_zero_mem"); let bcx = cx; memfill(&B(bcx), llptr, t, 0); } // Always use this function instead of storing a constant byte to the memory // in question. e.g. if you store a zero constant, LLVM will drown in vreg // allocation for large data structures, and the generated code will be // awful. (A telltale sign of this is large quantities of // `mov [byte ptr foo],0` in the generated code.) fn memfill<'a, 'tcx>(b: &Builder<'a, 'tcx>, llptr: ValueRef, ty: Ty<'tcx>, byte: u8) { let _icx = push_ctxt("memfill"); let ccx = b.ccx; let llty = type_of::type_of(ccx, ty); let intrinsic_key = match &ccx.sess().target.target.target_pointer_width[..] { "32" => "llvm.memset.p0i8.i32", "64" => "llvm.memset.p0i8.i64", tws => panic!("Unsupported target word size for memset: {}", tws), }; let llintrinsicfn = ccx.get_intrinsic(&intrinsic_key); let llptr = b.pointercast(llptr, Type::i8(ccx).ptr_to()); let llzeroval = C_u8(ccx, byte as usize); let size = machine::llsize_of(ccx, llty); let align = C_i32(ccx, type_of::align_of(ccx, ty) as i32); let volatile = C_bool(ccx, false); b.call(llintrinsicfn, &[llptr, llzeroval, size, align, volatile], None); } pub fn alloc_ty<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, t: Ty<'tcx>, name: &str) -> ValueRef { let _icx = push_ctxt("alloc_ty"); let ccx = bcx.ccx(); let ty = type_of::type_of(ccx, t); assert!(!ty::type_has_params(t)); let val = alloca(bcx, ty, name); return val; } pub fn alloca(cx: Block, ty: Type, name: &str) -> ValueRef { let p = alloca_no_lifetime(cx, ty, name); call_lifetime_start(cx, p); p } pub fn alloca_no_lifetime(cx: Block, ty: Type, name: &str) -> ValueRef { let _icx = push_ctxt("alloca"); if cx.unreachable.get() { unsafe { return llvm::LLVMGetUndef(ty.ptr_to().to_ref()); } } debuginfo::clear_source_location(cx.fcx); Alloca(cx, ty, name) } // Creates the alloca slot which holds the pointer to the slot for the final return value pub fn make_return_slot_pointer<'a, 'tcx>(fcx: &FunctionContext<'a, 'tcx>, output_type: Ty<'tcx>) -> ValueRef { let lloutputtype = type_of::type_of(fcx.ccx, output_type); // We create an alloca to hold a pointer of type `output_type` // which will hold the pointer to the right alloca which has the // final ret value if fcx.needs_ret_allocas { // Let's create the stack slot let slot = AllocaFcx(fcx, lloutputtype.ptr_to(), "llretslotptr"); // and if we're using an out pointer, then store that in our newly made slot if type_of::return_uses_outptr(fcx.ccx, output_type) { let outptr = get_param(fcx.llfn, 0); let b = fcx.ccx.builder(); b.position_before(fcx.alloca_insert_pt.get().unwrap()); b.store(outptr, slot); } slot // But if there are no nested returns, we skip the indirection and have a single // retslot } else { if type_of::return_uses_outptr(fcx.ccx, output_type) { get_param(fcx.llfn, 0) } else { AllocaFcx(fcx, lloutputtype, "sret_slot") } } } struct FindNestedReturn { found: bool, } impl FindNestedReturn { fn new() -> FindNestedReturn { FindNestedReturn { found: false } } } impl<'v> Visitor<'v> for FindNestedReturn { fn visit_expr(&mut self, e: &ast::Expr) { match e.node { ast::ExprRet(..) => { self.found = true; } _ => visit::walk_expr(self, e) } } } fn build_cfg(tcx: &ty::ctxt, id: ast::NodeId) -> (ast::NodeId, Option) { let blk = match tcx.map.find(id) { Some(ast_map::NodeItem(i)) => { match i.node { ast::ItemFn(_, _, _, _, ref blk) => { blk } _ => tcx.sess.bug("unexpected item variant in has_nested_returns") } } Some(ast_map::NodeTraitItem(trait_item)) => { match trait_item.node { ast::MethodTraitItem(_, Some(ref body)) => body, _ => { tcx.sess.bug("unexpected variant: trait item other than a \ provided method in has_nested_returns") } } } Some(ast_map::NodeImplItem(impl_item)) => { match impl_item.node { ast::MethodImplItem(_, ref body) => body, _ => { tcx.sess.bug("unexpected variant: non-method impl item in \ has_nested_returns") } } } Some(ast_map::NodeExpr(e)) => { match e.node { ast::ExprClosure(_, _, ref blk) => blk, _ => tcx.sess.bug("unexpected expr variant in has_nested_returns") } } Some(ast_map::NodeVariant(..)) | Some(ast_map::NodeStructCtor(..)) => return (ast::DUMMY_NODE_ID, None), // glue, shims, etc None if id == ast::DUMMY_NODE_ID => return (ast::DUMMY_NODE_ID, None), _ => tcx.sess.bug(&format!("unexpected variant in has_nested_returns: {}", tcx.map.path_to_string(id))) }; (blk.id, Some(cfg::CFG::new(tcx, blk))) } // Checks for the presence of "nested returns" in a function. // Nested returns are when the inner expression of a return expression // (the 'expr' in 'return expr') contains a return expression. Only cases // where the outer return is actually reachable are considered. Implicit // returns from the end of blocks are considered as well. // // This check is needed to handle the case where the inner expression is // part of a larger expression that may have already partially-filled the // return slot alloca. This can cause errors related to clean-up due to // the clobbering of the existing value in the return slot. fn has_nested_returns(tcx: &ty::ctxt, cfg: &cfg::CFG, blk_id: ast::NodeId) -> bool { for n in cfg.graph.depth_traverse(cfg.entry) { match tcx.map.find(n.id()) { Some(ast_map::NodeExpr(ex)) => { if let ast::ExprRet(Some(ref ret_expr)) = ex.node { let mut visitor = FindNestedReturn::new(); visit::walk_expr(&mut visitor, &**ret_expr); if visitor.found { return true; } } } Some(ast_map::NodeBlock(blk)) if blk.id == blk_id => { let mut visitor = FindNestedReturn::new(); visit::walk_expr_opt(&mut visitor, &blk.expr); if visitor.found { return true; } } _ => {} } } return false; } // NB: must keep 4 fns in sync: // // - type_of_fn // - create_datums_for_fn_args. // - new_fn_ctxt // - trans_args // // Be warned! You must call `init_function` before doing anything with the // returned function context. pub fn new_fn_ctxt<'a, 'tcx>(ccx: &'a CrateContext<'a, 'tcx>, llfndecl: ValueRef, id: ast::NodeId, has_env: bool, output_type: ty::FnOutput<'tcx>, param_substs: &'tcx Substs<'tcx>, sp: Option, block_arena: &'a TypedArena>) -> FunctionContext<'a, 'tcx> { common::validate_substs(param_substs); debug!("new_fn_ctxt(path={}, id={}, param_substs={})", if id == !0 { "".to_string() } else { ccx.tcx().map.path_to_string(id).to_string() }, id, param_substs.repr(ccx.tcx())); let uses_outptr = match output_type { ty::FnConverging(output_type) => { let substd_output_type = monomorphize::apply_param_substs(ccx.tcx(), param_substs, &output_type); type_of::return_uses_outptr(ccx, substd_output_type) } ty::FnDiverging => false }; let debug_context = debuginfo::create_function_debug_context(ccx, id, param_substs, llfndecl); let (blk_id, cfg) = build_cfg(ccx.tcx(), id); let nested_returns = if let Some(ref cfg) = cfg { has_nested_returns(ccx.tcx(), cfg, blk_id) } else { false }; let mut fcx = FunctionContext { llfn: llfndecl, llenv: None, llretslotptr: Cell::new(None), param_env: ty::empty_parameter_environment(ccx.tcx()), alloca_insert_pt: Cell::new(None), llreturn: Cell::new(None), needs_ret_allocas: nested_returns, personality: Cell::new(None), caller_expects_out_pointer: uses_outptr, lllocals: RefCell::new(NodeMap()), llupvars: RefCell::new(NodeMap()), id: id, param_substs: param_substs, span: sp, block_arena: block_arena, ccx: ccx, debug_context: debug_context, scopes: RefCell::new(Vec::new()), cfg: cfg }; if has_env { fcx.llenv = Some(get_param(fcx.llfn, fcx.env_arg_pos() as c_uint)) } fcx } /// Performs setup on a newly created function, creating the entry scope block /// and allocating space for the return pointer. pub fn init_function<'a, 'tcx>(fcx: &'a FunctionContext<'a, 'tcx>, skip_retptr: bool, output: ty::FnOutput<'tcx>) -> Block<'a, 'tcx> { let entry_bcx = fcx.new_temp_block("entry-block"); // Use a dummy instruction as the insertion point for all allocas. // This is later removed in FunctionContext::cleanup. fcx.alloca_insert_pt.set(Some(unsafe { Load(entry_bcx, C_null(Type::i8p(fcx.ccx))); llvm::LLVMGetFirstInstruction(entry_bcx.llbb) })); if let ty::FnConverging(output_type) = output { // This shouldn't need to recompute the return type, // as new_fn_ctxt did it already. let substd_output_type = fcx.monomorphize(&output_type); if !return_type_is_void(fcx.ccx, substd_output_type) { // If the function returns nil/bot, there is no real return // value, so do not set `llretslotptr`. if !skip_retptr || fcx.caller_expects_out_pointer { // Otherwise, we normally allocate the llretslotptr, unless we // have been instructed to skip it for immediate return // values. fcx.llretslotptr.set(Some(make_return_slot_pointer(fcx, substd_output_type))); } } } entry_bcx } // NB: must keep 4 fns in sync: // // - type_of_fn // - create_datums_for_fn_args. // - new_fn_ctxt // - trans_args pub fn arg_kind<'a, 'tcx>(cx: &FunctionContext<'a, 'tcx>, t: Ty<'tcx>) -> datum::Rvalue { use trans::datum::{ByRef, ByValue}; datum::Rvalue { mode: if arg_is_indirect(cx.ccx, t) { ByRef } else { ByValue } } } // work around bizarre resolve errors pub type RvalueDatum<'tcx> = datum::Datum<'tcx, datum::Rvalue>; // create_datums_for_fn_args: creates rvalue datums for each of the // incoming function arguments. These will later be stored into // appropriate lvalue datums. pub fn create_datums_for_fn_args<'a, 'tcx>(fcx: &FunctionContext<'a, 'tcx>, arg_tys: &[Ty<'tcx>]) -> Vec> { let _icx = push_ctxt("create_datums_for_fn_args"); // Return an array wrapping the ValueRefs that we get from `get_param` for // each argument into datums. arg_tys.iter().enumerate().map(|(i, &arg_ty)| { let llarg = get_param(fcx.llfn, fcx.arg_pos(i) as c_uint); datum::Datum::new(llarg, arg_ty, arg_kind(fcx, arg_ty)) }).collect() } /// Creates rvalue datums for each of the incoming function arguments and /// tuples the arguments. These will later be stored into appropriate lvalue /// datums. /// /// FIXME(pcwalton): Reduce the amount of code bloat this is responsible for. fn create_datums_for_fn_args_under_call_abi<'blk, 'tcx>( mut bcx: Block<'blk, 'tcx>, arg_scope: cleanup::CustomScopeIndex, arg_tys: &[Ty<'tcx>]) -> Vec> { let mut result = Vec::new(); for (i, &arg_ty) in arg_tys.iter().enumerate() { if i < arg_tys.len() - 1 { // Regular argument. let llarg = get_param(bcx.fcx.llfn, bcx.fcx.arg_pos(i) as c_uint); result.push(datum::Datum::new(llarg, arg_ty, arg_kind(bcx.fcx, arg_ty))); continue } // This is the last argument. Tuple it. match arg_ty.sty { ty::ty_tup(ref tupled_arg_tys) => { let tuple_args_scope_id = cleanup::CustomScope(arg_scope); let tuple = unpack_datum!(bcx, datum::lvalue_scratch_datum(bcx, arg_ty, "tupled_args", tuple_args_scope_id, (), |(), mut bcx, llval| { for (j, &tupled_arg_ty) in tupled_arg_tys.iter().enumerate() { let llarg = get_param(bcx.fcx.llfn, bcx.fcx.arg_pos(i + j) as c_uint); let lldest = GEPi(bcx, llval, &[0, j]); let datum = datum::Datum::new( llarg, tupled_arg_ty, arg_kind(bcx.fcx, tupled_arg_ty)); bcx = datum.store_to(bcx, lldest); } bcx })); let tuple = unpack_datum!(bcx, tuple.to_expr_datum() .to_rvalue_datum(bcx, "argtuple")); result.push(tuple); } _ => { bcx.tcx().sess.bug("last argument of a function with \ `rust-call` ABI isn't a tuple?!") } }; } result } fn copy_args_to_allocas<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, arg_scope: cleanup::CustomScopeIndex, args: &[ast::Arg], arg_datums: Vec>) -> Block<'blk, 'tcx> { debug!("copy_args_to_allocas"); let _icx = push_ctxt("copy_args_to_allocas"); let mut bcx = bcx; let arg_scope_id = cleanup::CustomScope(arg_scope); for (i, arg_datum) in arg_datums.into_iter().enumerate() { // For certain mode/type combinations, the raw llarg values are passed // by value. However, within the fn body itself, we want to always // have all locals and arguments be by-ref so that we can cancel the // cleanup and for better interaction with LLVM's debug info. So, if // the argument would be passed by value, we store it into an alloca. // This alloca should be optimized away by LLVM's mem-to-reg pass in // the event it's not truly needed. bcx = _match::store_arg(bcx, &*args[i].pat, arg_datum, arg_scope_id); debuginfo::create_argument_metadata(bcx, &args[i]); } bcx } // Ties up the llstaticallocas -> llloadenv -> lltop edges, // and builds the return block. pub fn finish_fn<'blk, 'tcx>(fcx: &'blk FunctionContext<'blk, 'tcx>, last_bcx: Block<'blk, 'tcx>, retty: ty::FnOutput<'tcx>, ret_debug_loc: DebugLoc) { let _icx = push_ctxt("finish_fn"); let ret_cx = match fcx.llreturn.get() { Some(llreturn) => { if !last_bcx.terminated.get() { Br(last_bcx, llreturn, DebugLoc::None); } raw_block(fcx, false, llreturn) } None => last_bcx }; // This shouldn't need to recompute the return type, // as new_fn_ctxt did it already. let substd_retty = fcx.monomorphize(&retty); build_return_block(fcx, ret_cx, substd_retty, ret_debug_loc); debuginfo::clear_source_location(fcx); fcx.cleanup(); } // Builds the return block for a function. pub fn build_return_block<'blk, 'tcx>(fcx: &FunctionContext<'blk, 'tcx>, ret_cx: Block<'blk, 'tcx>, retty: ty::FnOutput<'tcx>, ret_debug_location: DebugLoc) { if fcx.llretslotptr.get().is_none() || (!fcx.needs_ret_allocas && fcx.caller_expects_out_pointer) { return RetVoid(ret_cx, ret_debug_location); } let retslot = if fcx.needs_ret_allocas { Load(ret_cx, fcx.llretslotptr.get().unwrap()) } else { fcx.llretslotptr.get().unwrap() }; let retptr = Value(retslot); match retptr.get_dominating_store(ret_cx) { // If there's only a single store to the ret slot, we can directly return // the value that was stored and omit the store and the alloca Some(s) => { let retval = s.get_operand(0).unwrap().get(); s.erase_from_parent(); if retptr.has_no_uses() { retptr.erase_from_parent(); } let retval = if retty == ty::FnConverging(fcx.ccx.tcx().types.bool) { Trunc(ret_cx, retval, Type::i1(fcx.ccx)) } else { retval }; if fcx.caller_expects_out_pointer { if let ty::FnConverging(retty) = retty { store_ty(ret_cx, retval, get_param(fcx.llfn, 0), retty); } RetVoid(ret_cx, ret_debug_location) } else { Ret(ret_cx, retval, ret_debug_location) } } // Otherwise, copy the return value to the ret slot None => match retty { ty::FnConverging(retty) => { if fcx.caller_expects_out_pointer { memcpy_ty(ret_cx, get_param(fcx.llfn, 0), retslot, retty); RetVoid(ret_cx, ret_debug_location) } else { Ret(ret_cx, load_ty(ret_cx, retslot, retty), ret_debug_location) } } ty::FnDiverging => { if fcx.caller_expects_out_pointer { RetVoid(ret_cx, ret_debug_location) } else { Ret(ret_cx, C_undef(Type::nil(fcx.ccx)), ret_debug_location) } } } } } /// Builds an LLVM function out of a source function. /// /// If the function closes over its environment a closure will be returned. pub fn trans_closure<'a, 'b, 'tcx>(ccx: &CrateContext<'a, 'tcx>, decl: &ast::FnDecl, body: &ast::Block, llfndecl: ValueRef, param_substs: &'tcx Substs<'tcx>, fn_ast_id: ast::NodeId, _attributes: &[ast::Attribute], output_type: ty::FnOutput<'tcx>, abi: Abi, closure_env: closure::ClosureEnv<'b>) { ccx.stats().n_closures.set(ccx.stats().n_closures.get() + 1); let _icx = push_ctxt("trans_closure"); attributes::emit_uwtable(llfndecl, true); debug!("trans_closure(..., param_substs={})", param_substs.repr(ccx.tcx())); let has_env = match closure_env { closure::ClosureEnv::Closure(_) => true, closure::ClosureEnv::NotClosure => false, }; let (arena, fcx): (TypedArena<_>, FunctionContext); arena = TypedArena::new(); fcx = new_fn_ctxt(ccx, llfndecl, fn_ast_id, has_env, output_type, param_substs, Some(body.span), &arena); let mut bcx = init_function(&fcx, false, output_type); // cleanup scope for the incoming arguments let fn_cleanup_debug_loc = debuginfo::get_cleanup_debug_loc_for_ast_node(ccx, fn_ast_id, body.span, true); let arg_scope = fcx.push_custom_cleanup_scope_with_debug_loc(fn_cleanup_debug_loc); let block_ty = node_id_type(bcx, body.id); // Set up arguments to the function. let monomorphized_arg_types = decl.inputs.iter() .map(|arg| node_id_type(bcx, arg.id)) .collect::>(); let monomorphized_arg_types = match closure_env { closure::ClosureEnv::NotClosure => { monomorphized_arg_types } // Tuple up closure argument types for the "rust-call" ABI. closure::ClosureEnv::Closure(_) => { vec![ty::mk_tup(ccx.tcx(), monomorphized_arg_types)] } }; for monomorphized_arg_type in &monomorphized_arg_types { debug!("trans_closure: monomorphized_arg_type: {}", ty_to_string(ccx.tcx(), *monomorphized_arg_type)); } debug!("trans_closure: function lltype: {}", bcx.fcx.ccx.tn().val_to_string(bcx.fcx.llfn)); let arg_datums = match closure_env { closure::ClosureEnv::NotClosure if abi == RustCall => { create_datums_for_fn_args_under_call_abi(bcx, arg_scope, &monomorphized_arg_types[..]) } _ => { let arg_tys = untuple_arguments_if_necessary(ccx, &monomorphized_arg_types, abi); create_datums_for_fn_args(&fcx, &arg_tys) } }; bcx = copy_args_to_allocas(bcx, arg_scope, &decl.inputs, arg_datums); bcx = closure_env.load(bcx, cleanup::CustomScope(arg_scope)); // Up until here, IR instructions for this function have explicitly not been annotated with // source code location, so we don't step into call setup code. From here on, source location // emitting should be enabled. debuginfo::start_emitting_source_locations(&fcx); let dest = match fcx.llretslotptr.get() { Some(_) => expr::SaveIn(fcx.get_ret_slot(bcx, ty::FnConverging(block_ty), "iret_slot")), None => { assert!(type_is_zero_size(bcx.ccx(), block_ty)); expr::Ignore } }; // This call to trans_block is the place where we bridge between // translation calls that don't have a return value (trans_crate, // trans_mod, trans_item, et cetera) and those that do // (trans_block, trans_expr, et cetera). bcx = controlflow::trans_block(bcx, body, dest); match dest { expr::SaveIn(slot) if fcx.needs_ret_allocas => { Store(bcx, slot, fcx.llretslotptr.get().unwrap()); } _ => {} } match fcx.llreturn.get() { Some(_) => { Br(bcx, fcx.return_exit_block(), DebugLoc::None); fcx.pop_custom_cleanup_scope(arg_scope); } None => { // Microoptimization writ large: avoid creating a separate // llreturn basic block bcx = fcx.pop_and_trans_custom_cleanup_scope(bcx, arg_scope); } }; // Put return block after all other blocks. // This somewhat improves single-stepping experience in debugger. unsafe { let llreturn = fcx.llreturn.get(); if let Some(llreturn) = llreturn { llvm::LLVMMoveBasicBlockAfter(llreturn, bcx.llbb); } } let ret_debug_loc = DebugLoc::At(fn_cleanup_debug_loc.id, fn_cleanup_debug_loc.span); // Insert the mandatory first few basic blocks before lltop. finish_fn(&fcx, bcx, output_type, ret_debug_loc); } /// Creates an LLVM function corresponding to a source language function. pub fn trans_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, decl: &ast::FnDecl, body: &ast::Block, llfndecl: ValueRef, param_substs: &'tcx Substs<'tcx>, id: ast::NodeId, attrs: &[ast::Attribute]) { let _s = StatRecorder::new(ccx, ccx.tcx().map.path_to_string(id).to_string()); debug!("trans_fn(param_substs={})", param_substs.repr(ccx.tcx())); let _icx = push_ctxt("trans_fn"); let fn_ty = ty::node_id_to_type(ccx.tcx(), id); let output_type = ty::erase_late_bound_regions(ccx.tcx(), &ty::ty_fn_ret(fn_ty)); let abi = ty::ty_fn_abi(fn_ty); trans_closure(ccx, decl, body, llfndecl, param_substs, id, attrs, output_type, abi, closure::ClosureEnv::NotClosure); } pub fn trans_enum_variant<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, _enum_id: ast::NodeId, variant: &ast::Variant, _args: &[ast::VariantArg], disr: ty::Disr, param_substs: &'tcx Substs<'tcx>, llfndecl: ValueRef) { let _icx = push_ctxt("trans_enum_variant"); trans_enum_variant_or_tuple_like_struct( ccx, variant.node.id, disr, param_substs, llfndecl); } pub fn trans_named_tuple_constructor<'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>, ctor_ty: Ty<'tcx>, disr: ty::Disr, args: callee::CallArgs, dest: expr::Dest, debug_loc: DebugLoc) -> Result<'blk, 'tcx> { let ccx = bcx.fcx.ccx; let tcx = ccx.tcx(); let result_ty = match ctor_ty.sty { ty::ty_bare_fn(_, ref bft) => { ty::erase_late_bound_regions(bcx.tcx(), &bft.sig.output()).unwrap() } _ => ccx.sess().bug( &format!("trans_enum_variant_constructor: \ unexpected ctor return type {}", ctor_ty.repr(tcx))) }; // Get location to store the result. If the user does not care about // the result, just make a stack slot let llresult = match dest { expr::SaveIn(d) => d, expr::Ignore => { if !type_is_zero_size(ccx, result_ty) { alloc_ty(bcx, result_ty, "constructor_result") } else { C_undef(type_of::type_of(ccx, result_ty)) } } }; if !type_is_zero_size(ccx, result_ty) { match args { callee::ArgExprs(exprs) => { let fields = exprs.iter().map(|x| &**x).enumerate().collect::>(); bcx = expr::trans_adt(bcx, result_ty, disr, &fields[..], None, expr::SaveIn(llresult), debug_loc); } _ => ccx.sess().bug("expected expr as arguments for variant/struct tuple constructor") } } // If the caller doesn't care about the result // drop the temporary we made let bcx = match dest { expr::SaveIn(_) => bcx, expr::Ignore => { let bcx = glue::drop_ty(bcx, llresult, result_ty, debug_loc); if !type_is_zero_size(ccx, result_ty) { call_lifetime_end(bcx, llresult); } bcx } }; Result::new(bcx, llresult) } pub fn trans_tuple_struct<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, _fields: &[ast::StructField], ctor_id: ast::NodeId, param_substs: &'tcx Substs<'tcx>, llfndecl: ValueRef) { let _icx = push_ctxt("trans_tuple_struct"); trans_enum_variant_or_tuple_like_struct( ccx, ctor_id, 0, param_substs, llfndecl); } fn trans_enum_variant_or_tuple_like_struct<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, ctor_id: ast::NodeId, disr: ty::Disr, param_substs: &'tcx Substs<'tcx>, llfndecl: ValueRef) { let ctor_ty = ty::node_id_to_type(ccx.tcx(), ctor_id); let ctor_ty = monomorphize::apply_param_substs(ccx.tcx(), param_substs, &ctor_ty); let result_ty = match ctor_ty.sty { ty::ty_bare_fn(_, ref bft) => { ty::erase_late_bound_regions(ccx.tcx(), &bft.sig.output()) } _ => ccx.sess().bug( &format!("trans_enum_variant_or_tuple_like_struct: \ unexpected ctor return type {}", ty_to_string(ccx.tcx(), ctor_ty))) }; let (arena, fcx): (TypedArena<_>, FunctionContext); arena = TypedArena::new(); fcx = new_fn_ctxt(ccx, llfndecl, ctor_id, false, result_ty, param_substs, None, &arena); let bcx = init_function(&fcx, false, result_ty); assert!(!fcx.needs_ret_allocas); let arg_tys = ty::erase_late_bound_regions( ccx.tcx(), &ty::ty_fn_args(ctor_ty)); let arg_datums = create_datums_for_fn_args(&fcx, &arg_tys[..]); if !type_is_zero_size(fcx.ccx, result_ty.unwrap()) { let dest = fcx.get_ret_slot(bcx, result_ty, "eret_slot"); let repr = adt::represent_type(ccx, result_ty.unwrap()); for (i, arg_datum) in arg_datums.into_iter().enumerate() { let lldestptr = adt::trans_field_ptr(bcx, &*repr, dest, disr, i); arg_datum.store_to(bcx, lldestptr); } adt::trans_set_discr(bcx, &*repr, dest, disr); } finish_fn(&fcx, bcx, result_ty, DebugLoc::None); } fn enum_variant_size_lint(ccx: &CrateContext, enum_def: &ast::EnumDef, sp: Span, id: ast::NodeId) { let mut sizes = Vec::new(); // does no allocation if no pushes, thankfully let print_info = ccx.sess().print_enum_sizes(); let levels = ccx.tcx().node_lint_levels.borrow(); let lint_id = lint::LintId::of(lint::builtin::VARIANT_SIZE_DIFFERENCES); let lvlsrc = levels.get(&(id, lint_id)); let is_allow = lvlsrc.map_or(true, |&(lvl, _)| lvl == lint::Allow); if is_allow && !print_info { // we're not interested in anything here return } let ty = ty::node_id_to_type(ccx.tcx(), id); let avar = adt::represent_type(ccx, ty); match *avar { adt::General(_, ref variants, _) => { for var in variants { let mut size = 0; for field in var.fields.iter().skip(1) { // skip the discriminant size += llsize_of_real(ccx, sizing_type_of(ccx, *field)); } sizes.push(size); } }, _ => { /* its size is either constant or unimportant */ } } let (largest, slargest, largest_index) = sizes.iter().enumerate().fold((0, 0, 0), |(l, s, li), (idx, &size)| if size > l { (size, l, idx) } else if size > s { (l, size, li) } else { (l, s, li) } ); if print_info { let llty = type_of::sizing_type_of(ccx, ty); let sess = &ccx.tcx().sess; sess.span_note(sp, &*format!("total size: {} bytes", llsize_of_real(ccx, llty))); match *avar { adt::General(..) => { for (i, var) in enum_def.variants.iter().enumerate() { ccx.tcx().sess.span_note(var.span, &*format!("variant data: {} bytes", sizes[i])); } } _ => {} } } // we only warn if the largest variant is at least thrice as large as // the second-largest. if !is_allow && largest > slargest * 3 && slargest > 0 { // Use lint::raw_emit_lint rather than sess.add_lint because the lint-printing // pass for the latter already ran. lint::raw_emit_lint(&ccx.tcx().sess, lint::builtin::VARIANT_SIZE_DIFFERENCES, *lvlsrc.unwrap(), Some(sp), &format!("enum variant is more than three times larger \ ({} bytes) than the next largest (ignoring padding)", largest)); ccx.sess().span_note(enum_def.variants[largest_index].span, "this variant is the largest"); } } pub struct TransItemVisitor<'a, 'tcx: 'a> { pub ccx: &'a CrateContext<'a, 'tcx>, } impl<'a, 'tcx, 'v> Visitor<'v> for TransItemVisitor<'a, 'tcx> { fn visit_item(&mut self, i: &ast::Item) { trans_item(self.ccx, i); } } pub fn llvm_linkage_by_name(name: &str) -> Option { // Use the names from src/llvm/docs/LangRef.rst here. Most types are only // applicable to variable declarations and may not really make sense for // Rust code in the first place but whitelist them anyway and trust that // the user knows what s/he's doing. Who knows, unanticipated use cases // may pop up in the future. // // ghost, dllimport, dllexport and linkonce_odr_autohide are not supported // and don't have to be, LLVM treats them as no-ops. match name { "appending" => Some(llvm::AppendingLinkage), "available_externally" => Some(llvm::AvailableExternallyLinkage), "common" => Some(llvm::CommonLinkage), "extern_weak" => Some(llvm::ExternalWeakLinkage), "external" => Some(llvm::ExternalLinkage), "internal" => Some(llvm::InternalLinkage), "linkonce" => Some(llvm::LinkOnceAnyLinkage), "linkonce_odr" => Some(llvm::LinkOnceODRLinkage), "private" => Some(llvm::PrivateLinkage), "weak" => Some(llvm::WeakAnyLinkage), "weak_odr" => Some(llvm::WeakODRLinkage), _ => None, } } /// Enum describing the origin of an LLVM `Value`, for linkage purposes. #[derive(Copy, Clone)] pub enum ValueOrigin { /// The LLVM `Value` is in this context because the corresponding item was /// assigned to the current compilation unit. OriginalTranslation, /// The `Value`'s corresponding item was assigned to some other compilation /// unit, but the `Value` was translated in this context anyway because the /// item is marked `#[inline]`. InlinedCopy, } /// Set the appropriate linkage for an LLVM `ValueRef` (function or global). /// If the `llval` is the direct translation of a specific Rust item, `id` /// should be set to the `NodeId` of that item. (This mapping should be /// 1-to-1, so monomorphizations and drop/visit glue should have `id` set to /// `None`.) `llval_origin` indicates whether `llval` is the translation of an /// item assigned to `ccx`'s compilation unit or an inlined copy of an item /// assigned to a different compilation unit. pub fn update_linkage(ccx: &CrateContext, llval: ValueRef, id: Option, llval_origin: ValueOrigin) { match llval_origin { InlinedCopy => { // `llval` is a translation of an item defined in a separate // compilation unit. This only makes sense if there are at least // two compilation units. assert!(ccx.sess().opts.cg.codegen_units > 1); // `llval` is a copy of something defined elsewhere, so use // `AvailableExternallyLinkage` to avoid duplicating code in the // output. llvm::SetLinkage(llval, llvm::AvailableExternallyLinkage); return; }, OriginalTranslation => {}, } if let Some(id) = id { let item = ccx.tcx().map.get(id); if let ast_map::NodeItem(i) = item { if let Some(name) = attr::first_attr_value_str_by_name(&i.attrs, "linkage") { if let Some(linkage) = llvm_linkage_by_name(&name) { llvm::SetLinkage(llval, linkage); } else { ccx.sess().span_fatal(i.span, "invalid linkage specified"); } return; } } } match id { Some(id) if ccx.reachable().contains(&id) => { llvm::SetLinkage(llval, llvm::ExternalLinkage); }, _ => { // `id` does not refer to an item in `ccx.reachable`. if ccx.sess().opts.cg.codegen_units > 1 { llvm::SetLinkage(llval, llvm::ExternalLinkage); } else { llvm::SetLinkage(llval, llvm::InternalLinkage); } }, } } pub fn trans_item(ccx: &CrateContext, item: &ast::Item) { let _icx = push_ctxt("trans_item"); let from_external = ccx.external_srcs().borrow().contains_key(&item.id); match item.node { ast::ItemFn(ref decl, _fn_style, abi, ref generics, ref body) => { if !generics.is_type_parameterized() { let trans_everywhere = attr::requests_inline(&item.attrs); // Ignore `trans_everywhere` for cross-crate inlined items // (`from_external`). `trans_item` will be called once for each // compilation unit that references the item, so it will still get // translated everywhere it's needed. for (ref ccx, is_origin) in ccx.maybe_iter(!from_external && trans_everywhere) { let llfn = get_item_val(ccx, item.id); let empty_substs = ccx.tcx().mk_substs(Substs::trans_empty()); if abi != Rust { foreign::trans_rust_fn_with_foreign_abi(ccx, &**decl, &**body, &item.attrs, llfn, empty_substs, item.id, None); } else { trans_fn(ccx, &**decl, &**body, llfn, empty_substs, item.id, &item.attrs); } update_linkage(ccx, llfn, Some(item.id), if is_origin { OriginalTranslation } else { InlinedCopy }); if is_entry_fn(ccx.sess(), item.id) { create_entry_wrapper(ccx, item.span, llfn); // check for the #[rustc_error] annotation, which forces an // error in trans. This is used to write compile-fail tests // that actually test that compilation succeeds without // reporting an error. if ty::has_attr(ccx.tcx(), local_def(item.id), "rustc_error") { ccx.tcx().sess.span_fatal(item.span, "compilation successful"); } } } } // Be sure to travel more than just one layer deep to catch nested // items in blocks and such. let mut v = TransItemVisitor{ ccx: ccx }; v.visit_block(&**body); } ast::ItemImpl(_, _, ref generics, _, _, ref impl_items) => { meth::trans_impl(ccx, item.ident, &impl_items[..], generics, item.id); } ast::ItemMod(ref m) => { trans_mod(&ccx.rotate(), m); } ast::ItemEnum(ref enum_definition, ref gens) => { if gens.ty_params.is_empty() { // sizes only make sense for non-generic types enum_variant_size_lint(ccx, enum_definition, item.span, item.id); } } ast::ItemConst(_, ref expr) => { // Recurse on the expression to catch items in blocks let mut v = TransItemVisitor{ ccx: ccx }; v.visit_expr(&**expr); } ast::ItemStatic(_, m, ref expr) => { // Recurse on the expression to catch items in blocks let mut v = TransItemVisitor{ ccx: ccx }; v.visit_expr(&**expr); let g = consts::trans_static(ccx, m, item.id); update_linkage(ccx, g, Some(item.id), OriginalTranslation); // Do static_assert checking. It can't really be done much earlier // because we need to get the value of the bool out of LLVM if attr::contains_name(&item.attrs, "static_assert") { if !ty::type_is_bool(ty::expr_ty(ccx.tcx(), expr)) { ccx.sess().span_fatal(expr.span, "can only have static_assert on a static \ with type `bool`"); } if m == ast::MutMutable { ccx.sess().span_fatal(expr.span, "cannot have static_assert on a mutable \ static"); } let v = ccx.static_values().borrow().get(&item.id).unwrap().clone(); unsafe { if !(llvm::LLVMConstIntGetZExtValue(v) != 0) { ccx.sess().span_fatal(expr.span, "static assertion failed"); } } } }, ast::ItemForeignMod(ref foreign_mod) => { foreign::trans_foreign_mod(ccx, foreign_mod); } ast::ItemTrait(..) => { // Inside of this trait definition, we won't be actually translating any // functions, but the trait still needs to be walked. Otherwise default // methods with items will not get translated and will cause ICE's when // metadata time comes around. let mut v = TransItemVisitor{ ccx: ccx }; visit::walk_item(&mut v, item); } _ => {/* fall through */ } } } // Translate a module. Doing this amounts to translating the items in the // module; there ends up being no artifact (aside from linkage names) of // separate modules in the compiled program. That's because modules exist // only as a convenience for humans working with the code, to organize names // and control visibility. pub fn trans_mod(ccx: &CrateContext, m: &ast::Mod) { let _icx = push_ctxt("trans_mod"); for item in &m.items { trans_item(ccx, &**item); } } // only use this for foreign function ABIs and glue, use `register_fn` for Rust functions pub fn register_fn_llvmty(ccx: &CrateContext, sp: Span, sym: String, node_id: ast::NodeId, cc: llvm::CallConv, llfty: Type) -> ValueRef { debug!("register_fn_llvmty id={} sym={}", node_id, sym); let llfn = declare::define_fn(ccx, &sym[..], cc, llfty, ty::FnConverging(ty::mk_nil(ccx.tcx()))).unwrap_or_else(||{ ccx.sess().span_fatal(sp, &format!("symbol `{}` is already defined", sym)); }); finish_register_fn(ccx, sym, node_id, llfn); llfn } fn finish_register_fn(ccx: &CrateContext, sym: String, node_id: ast::NodeId, llfn: ValueRef) { ccx.item_symbols().borrow_mut().insert(node_id, sym); // The stack exhaustion lang item shouldn't have a split stack because // otherwise it would continue to be exhausted (bad), and both it and the // eh_personality functions need to be externally linkable. let def = ast_util::local_def(node_id); if ccx.tcx().lang_items.stack_exhausted() == Some(def) { attributes::split_stack(llfn, false); llvm::SetLinkage(llfn, llvm::ExternalLinkage); } if ccx.tcx().lang_items.eh_personality() == Some(def) { llvm::SetLinkage(llfn, llvm::ExternalLinkage); } } fn register_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, sp: Span, sym: String, node_id: ast::NodeId, node_type: Ty<'tcx>) -> ValueRef { if let ty::ty_bare_fn(_, ref f) = node_type.sty { if f.abi != Rust && f.abi != RustCall { ccx.sess().span_bug(sp, &format!("only the `{}` or `{}` calling conventions are valid \ for this function; `{}` was specified", Rust.name(), RustCall.name(), f.abi.name())); } } else { ccx.sess().span_bug(sp, "expected bare rust function") } let llfn = declare::define_rust_fn(ccx, &sym[..], node_type).unwrap_or_else(||{ ccx.sess().span_fatal(sp, &format!("symbol `{}` is already defined", sym)); }); finish_register_fn(ccx, sym, node_id, llfn); llfn } pub fn is_entry_fn(sess: &Session, node_id: ast::NodeId) -> bool { match *sess.entry_fn.borrow() { Some((entry_id, _)) => node_id == entry_id, None => false } } /// Create the `main` function which will initialise the rust runtime and call users’ main /// function. pub fn create_entry_wrapper(ccx: &CrateContext, sp: Span, main_llfn: ValueRef) { let et = ccx.sess().entry_type.get().unwrap(); match et { config::EntryMain => { create_entry_fn(ccx, sp, main_llfn, true); } config::EntryStart => create_entry_fn(ccx, sp, main_llfn, false), config::EntryNone => {} // Do nothing. } fn create_entry_fn(ccx: &CrateContext, sp: Span, rust_main: ValueRef, use_start_lang_item: bool) { let llfty = Type::func(&[ccx.int_type(), Type::i8p(ccx).ptr_to()], &ccx.int_type()); let llfn = declare::define_cfn(ccx, "main", llfty, ty::mk_nil(ccx.tcx())).unwrap_or_else(||{ ccx.sess().span_err(sp, "entry symbol `main` defined multiple times"); // FIXME: We should be smart and show a better diagnostic here. ccx.sess().help("did you use #[no_mangle] on `fn main`? Use #[start] instead"); ccx.sess().abort_if_errors(); panic!(); }); // FIXME: #16581: Marking a symbol in the executable with `dllexport` // linkage forces MinGW's linker to output a `.reloc` section for ASLR if ccx.sess().target.target.options.is_like_windows { unsafe { llvm::LLVMRustSetDLLExportStorageClass(llfn) } } let llbb = unsafe { llvm::LLVMAppendBasicBlockInContext(ccx.llcx(), llfn, "top\0".as_ptr() as *const _) }; let bld = ccx.raw_builder(); unsafe { llvm::LLVMPositionBuilderAtEnd(bld, llbb); debuginfo::gdb::insert_reference_to_gdb_debug_scripts_section_global(ccx); let (start_fn, args) = if use_start_lang_item { let start_def_id = match ccx.tcx().lang_items.require(StartFnLangItem) { Ok(id) => id, Err(s) => { ccx.sess().fatal(&s[..]); } }; let start_fn = if start_def_id.krate == ast::LOCAL_CRATE { get_item_val(ccx, start_def_id.node) } else { let start_fn_type = csearch::get_type(ccx.tcx(), start_def_id).ty; trans_external_path(ccx, start_def_id, start_fn_type) }; let args = { let opaque_rust_main = llvm::LLVMBuildPointerCast(bld, rust_main, Type::i8p(ccx).to_ref(), "rust_main\0".as_ptr() as *const _); vec!( opaque_rust_main, get_param(llfn, 0), get_param(llfn, 1) ) }; (start_fn, args) } else { debug!("using user-defined start fn"); let args = vec!( get_param(llfn, 0 as c_uint), get_param(llfn, 1 as c_uint) ); (rust_main, args) }; let result = llvm::LLVMBuildCall(bld, start_fn, args.as_ptr(), args.len() as c_uint, noname()); llvm::LLVMBuildRet(bld, result); } } } fn exported_name<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, id: ast::NodeId, ty: Ty<'tcx>, attrs: &[ast::Attribute]) -> String { match ccx.external_srcs().borrow().get(&id) { Some(&did) => { let sym = csearch::get_symbol(&ccx.sess().cstore, did); debug!("found item {} in other crate...", sym); return sym; } None => {} } match attr::find_export_name_attr(ccx.sess().diagnostic(), attrs) { // Use provided name Some(name) => name.to_string(), _ => ccx.tcx().map.with_path(id, |path| { if attr::contains_name(attrs, "no_mangle") { // Don't mangle path.last().unwrap().to_string() } else { match weak_lang_items::link_name(attrs) { Some(name) => name.to_string(), None => { // Usual name mangling mangle_exported_name(ccx, path, ty, id) } } } }) } } fn contains_null(s: &str) -> bool { s.bytes().any(|b| b == 0) } pub fn get_item_val(ccx: &CrateContext, id: ast::NodeId) -> ValueRef { debug!("get_item_val(id=`{}`)", id); match ccx.item_vals().borrow().get(&id).cloned() { Some(v) => return v, None => {} } let item = ccx.tcx().map.get(id); debug!("get_item_val: id={} item={:?}", id, item); let val = match item { ast_map::NodeItem(i) => { let ty = ty::node_id_to_type(ccx.tcx(), i.id); let sym = || exported_name(ccx, id, ty, &i.attrs); let v = match i.node { ast::ItemStatic(_, _, ref expr) => { // If this static came from an external crate, then // we need to get the symbol from csearch instead of // using the current crate's name/version // information in the hash of the symbol let sym = sym(); debug!("making {}", sym); // We need the translated value here, because for enums the // LLVM type is not fully determined by the Rust type. let empty_substs = ccx.tcx().mk_substs(Substs::trans_empty()); let (v, ty) = consts::const_expr(ccx, &**expr, empty_substs); ccx.static_values().borrow_mut().insert(id, v); unsafe { // boolean SSA values are i1, but they have to be stored in i8 slots, // otherwise some LLVM optimization passes don't work as expected let llty = if ty::type_is_bool(ty) { llvm::LLVMInt8TypeInContext(ccx.llcx()) } else { llvm::LLVMTypeOf(v) }; // FIXME(nagisa): probably should be declare_global, because no definition // is happening here, but we depend on it being defined here from // const::trans_static. This all logic should be replaced. let g = declare::define_global(ccx, &sym[..], Type::from_ref(llty)).unwrap_or_else(||{ ccx.sess().span_fatal(i.span, &format!("symbol `{}` is already defined", sym)) }); if attr::contains_name(&i.attrs, "thread_local") { llvm::set_thread_local(g, true); } ccx.item_symbols().borrow_mut().insert(i.id, sym); g } } ast::ItemFn(_, _, abi, _, _) => { let sym = sym(); let llfn = if abi == Rust { register_fn(ccx, i.span, sym, i.id, ty) } else { foreign::register_rust_fn_with_foreign_abi(ccx, i.span, sym, i.id) }; attributes::from_fn_attrs(ccx, &i.attrs, llfn); llfn } _ => ccx.sess().bug("get_item_val: weird result in table") }; match attr::first_attr_value_str_by_name(&i.attrs, "link_section") { Some(sect) => { if contains_null(§) { ccx.sess().fatal(&format!("Illegal null byte in link_section value: `{}`", §)); } unsafe { let buf = CString::new(sect.as_bytes()).unwrap(); llvm::LLVMSetSection(v, buf.as_ptr()); } }, None => () } v } ast_map::NodeTraitItem(trait_item) => { debug!("get_item_val(): processing a NodeTraitItem"); match trait_item.node { ast::MethodTraitItem(_, Some(_)) => { register_method(ccx, id, &trait_item.attrs, trait_item.span) } _ => { ccx.sess().span_bug(trait_item.span, "unexpected variant: trait item other than a provided \ method in get_item_val()"); } } } ast_map::NodeImplItem(impl_item) => { match impl_item.node { ast::MethodImplItem(..) => { register_method(ccx, id, &impl_item.attrs, impl_item.span) } _ => { ccx.sess().span_bug(impl_item.span, "unexpected variant: non-method impl item in \ get_item_val()"); } } } ast_map::NodeForeignItem(ni) => { match ni.node { ast::ForeignItemFn(..) => { let abi = ccx.tcx().map.get_foreign_abi(id); let ty = ty::node_id_to_type(ccx.tcx(), ni.id); let name = foreign::link_name(&*ni); let llfn = foreign::register_foreign_item_fn(ccx, abi, ty, &name); attributes::from_fn_attrs(ccx, &ni.attrs, llfn); llfn } ast::ForeignItemStatic(..) => { foreign::register_static(ccx, &*ni) } } } ast_map::NodeVariant(ref v) => { let llfn; let args = match v.node.kind { ast::TupleVariantKind(ref args) => args, ast::StructVariantKind(_) => { ccx.sess().bug("struct variant kind unexpected in get_item_val") } }; assert!(!args.is_empty()); let ty = ty::node_id_to_type(ccx.tcx(), id); let parent = ccx.tcx().map.get_parent(id); let enm = ccx.tcx().map.expect_item(parent); let sym = exported_name(ccx, id, ty, &enm.attrs); llfn = match enm.node { ast::ItemEnum(_, _) => { register_fn(ccx, (*v).span, sym, id, ty) } _ => ccx.sess().bug("NodeVariant, shouldn't happen") }; attributes::inline(llfn, attributes::InlineAttr::Hint); llfn } ast_map::NodeStructCtor(struct_def) => { // Only register the constructor if this is a tuple-like struct. let ctor_id = match struct_def.ctor_id { None => { ccx.sess().bug("attempt to register a constructor of \ a non-tuple-like struct") } Some(ctor_id) => ctor_id, }; let parent = ccx.tcx().map.get_parent(id); let struct_item = ccx.tcx().map.expect_item(parent); let ty = ty::node_id_to_type(ccx.tcx(), ctor_id); let sym = exported_name(ccx, id, ty, &struct_item.attrs); let llfn = register_fn(ccx, struct_item.span, sym, ctor_id, ty); attributes::inline(llfn, attributes::InlineAttr::Hint); llfn } ref variant => { ccx.sess().bug(&format!("get_item_val(): unexpected variant: {:?}", variant)) } }; // All LLVM globals and functions are initially created as external-linkage // declarations. If `trans_item`/`trans_fn` later turns the declaration // into a definition, it adjusts the linkage then (using `update_linkage`). // // The exception is foreign items, which have their linkage set inside the // call to `foreign::register_*` above. We don't touch the linkage after // that (`foreign::trans_foreign_mod` doesn't adjust the linkage like the // other item translation functions do). ccx.item_vals().borrow_mut().insert(id, val); val } fn register_method(ccx: &CrateContext, id: ast::NodeId, attrs: &[ast::Attribute], span: Span) -> ValueRef { let mty = ty::node_id_to_type(ccx.tcx(), id); let sym = exported_name(ccx, id, mty, &attrs); if let ty::ty_bare_fn(_, ref f) = mty.sty { let llfn = if f.abi == Rust || f.abi == RustCall { register_fn(ccx, span, sym, id, mty) } else { foreign::register_rust_fn_with_foreign_abi(ccx, span, sym, id) }; attributes::from_fn_attrs(ccx, &attrs, llfn); return llfn; } else { ccx.sess().span_bug(span, "expected bare rust function"); } } pub fn crate_ctxt_to_encode_parms<'a, 'tcx>(cx: &'a SharedCrateContext<'tcx>, ie: encoder::EncodeInlinedItem<'a>) -> encoder::EncodeParams<'a, 'tcx> { encoder::EncodeParams { diag: cx.sess().diagnostic(), tcx: cx.tcx(), reexports: cx.export_map(), item_symbols: cx.item_symbols(), link_meta: cx.link_meta(), cstore: &cx.sess().cstore, encode_inlined_item: ie, reachable: cx.reachable(), } } pub fn write_metadata(cx: &SharedCrateContext, krate: &ast::Crate) -> Vec { use flate; let any_library = cx.sess().crate_types.borrow().iter().any(|ty| { *ty != config::CrateTypeExecutable }); if !any_library { return Vec::new() } let encode_inlined_item: encoder::EncodeInlinedItem = Box::new(|ecx, rbml_w, ii| astencode::encode_inlined_item(ecx, rbml_w, ii)); let encode_parms = crate_ctxt_to_encode_parms(cx, encode_inlined_item); let metadata = encoder::encode_metadata(encode_parms, krate); let mut compressed = encoder::metadata_encoding_version.to_vec(); compressed.push_all(&flate::deflate_bytes(&metadata)); let llmeta = C_bytes_in_context(cx.metadata_llcx(), &compressed[..]); let llconst = C_struct_in_context(cx.metadata_llcx(), &[llmeta], false); let name = format!("rust_metadata_{}_{}", cx.link_meta().crate_name, cx.link_meta().crate_hash); let buf = CString::new(name).unwrap(); let llglobal = unsafe { llvm::LLVMAddGlobal(cx.metadata_llmod(), val_ty(llconst).to_ref(), buf.as_ptr()) }; unsafe { llvm::LLVMSetInitializer(llglobal, llconst); let name = loader::meta_section_name(cx.sess().target.target.options.is_like_osx); let name = CString::new(name).unwrap(); llvm::LLVMSetSection(llglobal, name.as_ptr()) } return metadata; } /// Find any symbols that are defined in one compilation unit, but not declared /// in any other compilation unit. Give these symbols internal linkage. fn internalize_symbols(cx: &SharedCrateContext, reachable: &HashSet) { unsafe { let mut declared = HashSet::new(); let iter_globals = |llmod| { ValueIter { cur: llvm::LLVMGetFirstGlobal(llmod), step: llvm::LLVMGetNextGlobal, } }; let iter_functions = |llmod| { ValueIter { cur: llvm::LLVMGetFirstFunction(llmod), step: llvm::LLVMGetNextFunction, } }; // Collect all external declarations in all compilation units. for ccx in cx.iter() { for val in iter_globals(ccx.llmod()).chain(iter_functions(ccx.llmod())) { let linkage = llvm::LLVMGetLinkage(val); // We only care about external declarations (not definitions) // and available_externally definitions. if !(linkage == llvm::ExternalLinkage as c_uint && llvm::LLVMIsDeclaration(val) != 0) && !(linkage == llvm::AvailableExternallyLinkage as c_uint) { continue } let name = CStr::from_ptr(llvm::LLVMGetValueName(val)) .to_bytes().to_vec(); declared.insert(name); } } // Examine each external definition. If the definition is not used in // any other compilation unit, and is not reachable from other crates, // then give it internal linkage. for ccx in cx.iter() { for val in iter_globals(ccx.llmod()).chain(iter_functions(ccx.llmod())) { // We only care about external definitions. if !(llvm::LLVMGetLinkage(val) == llvm::ExternalLinkage as c_uint && llvm::LLVMIsDeclaration(val) == 0) { continue } let name = CStr::from_ptr(llvm::LLVMGetValueName(val)) .to_bytes().to_vec(); if !declared.contains(&name) && !reachable.contains(str::from_utf8(&name).unwrap()) { llvm::SetLinkage(val, llvm::InternalLinkage); } } } } struct ValueIter { cur: ValueRef, step: unsafe extern "C" fn(ValueRef) -> ValueRef, } impl Iterator for ValueIter { type Item = ValueRef; fn next(&mut self) -> Option { let old = self.cur; if !old.is_null() { self.cur = unsafe { let step: unsafe extern "C" fn(ValueRef) -> ValueRef = mem::transmute_copy(&self.step); step(old) }; Some(old) } else { None } } } } pub fn trans_crate<'tcx>(analysis: ty::CrateAnalysis<'tcx>) -> (ty::ctxt<'tcx>, CrateTranslation) { let ty::CrateAnalysis { ty_cx: tcx, export_map, reachable, name, .. } = analysis; let krate = tcx.map.krate(); let check_overflow = if let Some(v) = tcx.sess.opts.debugging_opts.force_overflow_checks { v } else { tcx.sess.opts.debug_assertions }; let check_dropflag = if let Some(v) = tcx.sess.opts.debugging_opts.force_dropflag_checks { v } else { tcx.sess.opts.debug_assertions }; // Before we touch LLVM, make sure that multithreading is enabled. unsafe { use std::sync::{Once, ONCE_INIT}; static INIT: Once = ONCE_INIT; static mut POISONED: bool = false; INIT.call_once(|| { if llvm::LLVMStartMultithreaded() != 1 { // use an extra bool to make sure that all future usage of LLVM // cannot proceed despite the Once not running more than once. POISONED = true; } }); if POISONED { tcx.sess.bug("couldn't enable multi-threaded LLVM"); } } let link_meta = link::build_link_meta(&tcx.sess, krate, name); let codegen_units = tcx.sess.opts.cg.codegen_units; let shared_ccx = SharedCrateContext::new(&link_meta.crate_name, codegen_units, tcx, export_map, Sha256::new(), link_meta.clone(), reachable, check_overflow, check_dropflag); { let ccx = shared_ccx.get_ccx(0); // First, verify intrinsics. intrinsic::check_intrinsics(&ccx); // Next, translate the module. { let _icx = push_ctxt("text"); trans_mod(&ccx, &krate.module); } } for ccx in shared_ccx.iter() { if ccx.sess().opts.debuginfo != NoDebugInfo { debuginfo::finalize(&ccx); } } // Translate the metadata. let metadata = write_metadata(&shared_ccx, krate); if shared_ccx.sess().trans_stats() { let stats = shared_ccx.stats(); println!("--- trans stats ---"); println!("n_glues_created: {}", stats.n_glues_created.get()); println!("n_null_glues: {}", stats.n_null_glues.get()); println!("n_real_glues: {}", stats.n_real_glues.get()); println!("n_fns: {}", stats.n_fns.get()); println!("n_monos: {}", stats.n_monos.get()); println!("n_inlines: {}", stats.n_inlines.get()); println!("n_closures: {}", stats.n_closures.get()); println!("fn stats:"); stats.fn_stats.borrow_mut().sort_by(|&(_, insns_a), &(_, insns_b)| { insns_b.cmp(&insns_a) }); for tuple in &*stats.fn_stats.borrow() { match *tuple { (ref name, insns) => { println!("{} insns, {}", insns, *name); } } } } if shared_ccx.sess().count_llvm_insns() { for (k, v) in &*shared_ccx.stats().llvm_insns.borrow() { println!("{:7} {}", *v, *k); } } let modules = shared_ccx.iter() .map(|ccx| ModuleTranslation { llcx: ccx.llcx(), llmod: ccx.llmod() }) .collect(); let mut reachable: Vec = shared_ccx.reachable().iter().filter_map(|id| { shared_ccx.item_symbols().borrow().get(id).map(|s| s.to_string()) }).collect(); // For the purposes of LTO, we add to the reachable set all of the upstream // reachable extern fns. These functions are all part of the public ABI of // the final product, so LTO needs to preserve them. shared_ccx.sess().cstore.iter_crate_data(|cnum, _| { let syms = csearch::get_reachable_extern_fns(&shared_ccx.sess().cstore, cnum); reachable.extend(syms.into_iter().map(|did| { csearch::get_symbol(&shared_ccx.sess().cstore, did) })); }); // Make sure that some other crucial symbols are not eliminated from the // module. This includes the main function, the crate map (used for debug // log settings and I/O), and finally the curious rust_stack_exhausted // symbol. This symbol is required for use by the libmorestack library that // we link in, so we must ensure that this symbol is not internalized (if // defined in the crate). reachable.push("main".to_string()); reachable.push("rust_stack_exhausted".to_string()); // referenced from .eh_frame section on some platforms reachable.push("rust_eh_personality".to_string()); // referenced from rt/rust_try.ll reachable.push("rust_eh_personality_catch".to_string()); if codegen_units > 1 { internalize_symbols(&shared_ccx, &reachable.iter().cloned().collect()); } let metadata_module = ModuleTranslation { llcx: shared_ccx.metadata_llcx(), llmod: shared_ccx.metadata_llmod(), }; let formats = shared_ccx.tcx().dependency_formats.borrow().clone(); let no_builtins = attr::contains_name(&krate.attrs, "no_builtins"); let translation = CrateTranslation { modules: modules, metadata_module: metadata_module, link: link_meta, metadata: metadata, reachable: reachable, crate_formats: formats, no_builtins: no_builtins, }; (shared_ccx.take_tcx(), translation) }