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