src/librustc_trans/trans_item.rs

   1 // Copyright 2016 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.
   4 //
   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.
  10
  11 //! Walks the crate looking for items/impl-items/trait-items that have
  12 //! either a `rustc_symbol_name` or `rustc_item_path` attribute and
  13 //! generates an error giving, respectively, the symbol name or
  14 //! item-path. This is used for unit testing the code that generates
  15 //! paths etc in all kinds of annoying scenarios.
  16
  17 use asm;
  18 use attributes;
  19 use base;
  20 use consts;
  21 use context::CrateContext;
  22 use declare;
  23 use llvm;
  24 use monomorphize::Instance;
  25 use type_of::LayoutLlvmExt;
  26 use rustc::hir;
  27 use rustc::mir::mono::{Linkage, Visibility};
  28 use rustc::ty::{TyCtxt, TypeFoldable};
  29 use rustc::ty::layout::LayoutOf;
  30 use syntax::ast;
  31 use syntax::attr;
  32 use syntax_pos::Span;
  33 use std::fmt;
  34
  35 pub use rustc::mir::mono::MonoItem;
  36
  37 pub use rustc_mir::monomorphize::item::*;
  38 pub use rustc_mir::monomorphize::item::MonoItemExt as BaseMonoItemExt;
  39
  40 pub trait MonoItemExt<'a, 'tcx>: fmt::Debug + BaseMonoItemExt<'a, 'tcx> {
  41     fn define(&self, ccx: &CrateContext<'a, 'tcx>) {
  42         debug!("BEGIN IMPLEMENTING '{} ({})' in cgu {}",
  43                self.to_string(ccx.tcx()),
  44                self.to_raw_string(),
  45                ccx.codegen_unit().name());
  46
  47         match *self.as_mono_item() {
  48             MonoItem::Static(node_id) => {
  49                 let tcx = ccx.tcx();
  50                 let item = tcx.hir.expect_item(node_id);
  51                 if let hir::ItemStatic(_, m, _) = item.node {
  52                     match consts::trans_static(&ccx, m, item.id, &item.attrs) {
  53                         Ok(_) => { /* Cool, everything's alright. */ },
  54                         Err(err) => {
  55                             err.report(tcx, item.span, "static");
  56                         }
  57                     };
  58                 } else {
  59                     span_bug!(item.span, "Mismatch between hir::Item type and TransItem type")
  60                 }
  61             }
  62             MonoItem::GlobalAsm(node_id) => {
  63                 let item = ccx.tcx().hir.expect_item(node_id);
  64                 if let hir::ItemGlobalAsm(ref ga) = item.node {
  65                     asm::trans_global_asm(ccx, ga);
  66                 } else {
  67                     span_bug!(item.span, "Mismatch between hir::Item type and TransItem type")
  68                 }
  69             }
  70             MonoItem::Fn(instance) => {
  71                 base::trans_instance(&ccx, instance);
  72             }
  73         }
  74
  75         debug!("END IMPLEMENTING '{} ({})' in cgu {}",
  76                self.to_string(ccx.tcx()),
  77                self.to_raw_string(),
  78                ccx.codegen_unit().name());
  79     }
  80
  81     fn predefine(&self,
  82                  ccx: &CrateContext<'a, 'tcx>,
  83                  linkage: Linkage,
  84                  visibility: Visibility) {
  85         debug!("BEGIN PREDEFINING '{} ({})' in cgu {}",
  86                self.to_string(ccx.tcx()),
  87                self.to_raw_string(),
  88                ccx.codegen_unit().name());
  89
  90         let symbol_name = self.symbol_name(ccx.tcx());
  91
  92         debug!("symbol {}", &symbol_name);
  93
  94         match *self.as_mono_item() {
  95             MonoItem::Static(node_id) => {
  96                 predefine_static(ccx, node_id, linkage, visibility, &symbol_name);
  97             }
  98             MonoItem::Fn(instance) => {
  99                 predefine_fn(ccx, instance, linkage, visibility, &symbol_name);
 100             }
 101             MonoItem::GlobalAsm(..) => {}
 102         }
 103
 104         debug!("END PREDEFINING '{} ({})' in cgu {}",
 105                self.to_string(ccx.tcx()),
 106                self.to_raw_string(),
 107                ccx.codegen_unit().name());
 108     }
 109
 110     fn local_span(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> Option<Span> {
 111         match *self.as_mono_item() {
 112             MonoItem::Fn(Instance { def, .. }) => {
 113                 tcx.hir.as_local_node_id(def.def_id())
 114             }
 115             MonoItem::Static(node_id) |
 116             MonoItem::GlobalAsm(node_id) => {
 117                 Some(node_id)
 118             }
 119         }.map(|node_id| tcx.hir.span(node_id))
 120     }
 121
 122     fn to_raw_string(&self) -> String {
 123         match *self.as_mono_item() {
 124             MonoItem::Fn(instance) => {
 125                 format!("Fn({:?}, {})",
 126                          instance.def,
 127                          instance.substs.as_ptr() as usize)
 128             }
 129             MonoItem::Static(id) => {
 130                 format!("Static({:?})", id)
 131             }
 132             MonoItem::GlobalAsm(id) => {
 133                 format!("GlobalAsm({:?})", id)
 134             }
 135         }
 136     }
 137 }
 138
 139 impl<'a, 'tcx> MonoItemExt<'a, 'tcx> for MonoItem<'tcx> {}
 140
 141 fn predefine_static<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
 142                               node_id: ast::NodeId,
 143                               linkage: Linkage,
 144                               visibility: Visibility,
 145                               symbol_name: &str) {
 146     let def_id = ccx.tcx().hir.local_def_id(node_id);
 147     let instance = Instance::mono(ccx.tcx(), def_id);
 148     let ty = instance.ty(ccx.tcx());
 149     let llty = ccx.layout_of(ty).llvm_type(ccx);
 150
 151     let g = declare::define_global(ccx, symbol_name, llty).unwrap_or_else(|| {
 152         ccx.sess().span_fatal(ccx.tcx().hir.span(node_id),
 153             &format!("symbol `{}` is already defined", symbol_name))
 154     });
 155
 156     unsafe {
 157         llvm::LLVMRustSetLinkage(g, base::linkage_to_llvm(linkage));
 158         llvm::LLVMRustSetVisibility(g, base::visibility_to_llvm(visibility));
 159     }
 160
 161     ccx.instances().borrow_mut().insert(instance, g);
 162     ccx.statics().borrow_mut().insert(g, def_id);
 163 }
 164
 165 fn predefine_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
 166                           instance: Instance<'tcx>,
 167                           linkage: Linkage,
 168                           visibility: Visibility,
 169                           symbol_name: &str) {
 170     assert!(!instance.substs.needs_infer() &&
 171             !instance.substs.has_param_types());
 172
 173     let mono_ty = instance.ty(ccx.tcx());
 174     let attrs = instance.def.attrs(ccx.tcx());
 175     let lldecl = declare::declare_fn(ccx, symbol_name, mono_ty);
 176     unsafe { llvm::LLVMRustSetLinkage(lldecl, base::linkage_to_llvm(linkage)) };
 177     base::set_link_section(ccx, lldecl, &attrs);
 178     if linkage == Linkage::LinkOnceODR ||
 179         linkage == Linkage::WeakODR {
 180         llvm::SetUniqueComdat(ccx.llmod(), lldecl);
 181     }
 182
 183     // If we're compiling the compiler-builtins crate, e.g. the equivalent of
 184     // compiler-rt, then we want to implicitly compile everything with hidden
 185     // visibility as we're going to link this object all over the place but
 186     // don't want the symbols to get exported.
 187     if linkage != Linkage::Internal && linkage != Linkage::Private &&
 188        attr::contains_name(ccx.tcx().hir.krate_attrs(), "compiler_builtins") {
 189         unsafe {
 190             llvm::LLVMRustSetVisibility(lldecl, llvm::Visibility::Hidden);
 191         }
 192     } else {
 193         unsafe {
 194             llvm::LLVMRustSetVisibility(lldecl, base::visibility_to_llvm(visibility));
 195         }
 196     }
 197
 198     debug!("predefine_fn: mono_ty = {:?} instance = {:?}", mono_ty, instance);
 199     if instance.def.is_inline(ccx.tcx()) {
 200         attributes::inline(lldecl, attributes::InlineAttr::Hint);
 201     }
 202     attributes::from_fn_attrs(ccx, lldecl, instance.def.def_id());
 203
 204     ccx.instances().borrow_mut().insert(instance, lldecl);
 205 }