src/librustc_codegen_llvm/mono_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 use attributes;
  12 use base;
  13 use context::CodegenCx;
  14 use llvm;
  15 use monomorphize::Instance;
  16 use type_of::LayoutLlvmExt;
  17 use rustc::hir::def_id::{DefId, LOCAL_CRATE};
  18 use rustc::mir::mono::{Linkage, Visibility};
  19 use rustc::ty::TypeFoldable;
  20 use rustc::ty::layout::{LayoutOf, HasTyCtxt};
  21 use rustc_codegen_ssa::traits::*;
  22
  23 pub use rustc::mir::mono::MonoItem;
  24
  25 impl PreDefineMethods<'tcx> for CodegenCx<'ll, 'tcx> {
  26     fn predefine_static(&self,
  27                                   def_id: DefId,
  28                                   linkage: Linkage,
  29                                   visibility: Visibility,
  30                                   symbol_name: &str) {
  31         let instance = Instance::mono(self.tcx, def_id);
  32         let ty = instance.ty(self.tcx);
  33         let llty = self.layout_of(ty).llvm_type(self);
  34
  35         let g = self.define_global(symbol_name, llty).unwrap_or_else(|| {
  36             self.sess().span_fatal(self.tcx.def_span(def_id),
  37                 &format!("symbol `{}` is already defined", symbol_name))
  38         });
  39
  40         unsafe {
  41             llvm::LLVMRustSetLinkage(g, base::linkage_to_llvm(linkage));
  42             llvm::LLVMRustSetVisibility(g, base::visibility_to_llvm(visibility));
  43         }
  44
  45         self.instances.borrow_mut().insert(instance, g);
  46     }
  47
  48     fn predefine_fn(&self,
  49                               instance: Instance<'tcx>,
  50                               linkage: Linkage,
  51                               visibility: Visibility,
  52                               symbol_name: &str) {
  53         assert!(!instance.substs.needs_infer() &&
  54                 !instance.substs.has_param_types());
  55
  56         let mono_sig = instance.fn_sig(self.tcx());
  57         let attrs = self.tcx.codegen_fn_attrs(instance.def_id());
  58         let lldecl = self.declare_fn(symbol_name, mono_sig);
  59         unsafe { llvm::LLVMRustSetLinkage(lldecl, base::linkage_to_llvm(linkage)) };
  60         base::set_link_section(lldecl, &attrs);
  61         if linkage == Linkage::LinkOnceODR ||
  62             linkage == Linkage::WeakODR {
  63             llvm::SetUniqueComdat(self.llmod, lldecl);
  64         }
  65
  66         // If we're compiling the compiler-builtins crate, e.g. the equivalent of
  67         // compiler-rt, then we want to implicitly compile everything with hidden
  68         // visibility as we're going to link this object all over the place but
  69         // don't want the symbols to get exported.
  70         if linkage != Linkage::Internal && linkage != Linkage::Private &&
  71            self.tcx.is_compiler_builtins(LOCAL_CRATE) {
  72             unsafe {
  73                 llvm::LLVMRustSetVisibility(lldecl, llvm::Visibility::Hidden);
  74             }
  75         } else {
  76             unsafe {
  77                 llvm::LLVMRustSetVisibility(lldecl, base::visibility_to_llvm(visibility));
  78             }
  79         }
  80
  81         debug!("predefine_fn: mono_sig = {:?} instance = {:?}", mono_sig, instance);
  82         if instance.def.is_inline(self.tcx) {
  83             attributes::inline(self, lldecl, attributes::InlineAttr::Hint);
  84         }
  85         attributes::from_fn_attrs(self, lldecl, Some(instance.def.def_id()));
  86
  87         self.instances.borrow_mut().insert(instance, lldecl);
  88     }
  89 }