src/librustc_codegen_llvm/mono_item.rs

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