| // Copyright 2012 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 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| |
| use llvm; |
| use llvm::{SetUnnamedAddr}; |
| use llvm::{ValueRef, True}; |
| use rustc_const_eval::ConstEvalErr; |
| use rustc::hir::def_id::DefId; |
| use rustc::hir::map as hir_map; |
| use {debuginfo, machine}; |
| use base; |
| use trans_item::TransItem; |
| use common::{CrateContext, val_ty}; |
| use declare; |
| use monomorphize::{Instance}; |
| use type_::Type; |
| use type_of; |
| use rustc::ty; |
| |
| use rustc::hir; |
| |
| use std::ffi::{CStr, CString}; |
| use syntax::ast; |
| use syntax::attr; |
| |
| pub fn ptrcast(val: ValueRef, ty: Type) -> ValueRef { |
| unsafe { |
| llvm::LLVMConstPointerCast(val, ty.to_ref()) |
| } |
| } |
| |
| pub fn addr_of_mut(ccx: &CrateContext, |
| cv: ValueRef, |
| align: machine::llalign, |
| kind: &str) |
| -> ValueRef { |
| unsafe { |
| let name = ccx.generate_local_symbol_name(kind); |
| let gv = declare::define_global(ccx, &name[..], val_ty(cv)).unwrap_or_else(||{ |
| bug!("symbol `{}` is already defined", name); |
| }); |
| llvm::LLVMSetInitializer(gv, cv); |
| llvm::LLVMSetAlignment(gv, align); |
| llvm::LLVMRustSetLinkage(gv, llvm::Linkage::InternalLinkage); |
| SetUnnamedAddr(gv, true); |
| gv |
| } |
| } |
| |
| pub fn addr_of(ccx: &CrateContext, |
| cv: ValueRef, |
| align: machine::llalign, |
| kind: &str) |
| -> ValueRef { |
| if let Some(&gv) = ccx.const_globals().borrow().get(&cv) { |
| unsafe { |
| // Upgrade the alignment in cases where the same constant is used with different |
| // alignment requirements |
| if align > llvm::LLVMGetAlignment(gv) { |
| llvm::LLVMSetAlignment(gv, align); |
| } |
| } |
| return gv; |
| } |
| let gv = addr_of_mut(ccx, cv, align, kind); |
| unsafe { |
| llvm::LLVMSetGlobalConstant(gv, True); |
| } |
| ccx.const_globals().borrow_mut().insert(cv, gv); |
| gv |
| } |
| |
| pub fn get_static(ccx: &CrateContext, def_id: DefId) -> ValueRef { |
| let instance = Instance::mono(ccx.shared(), def_id); |
| if let Some(&g) = ccx.instances().borrow().get(&instance) { |
| return g; |
| } |
| |
| let ty = ccx.tcx().item_type(def_id); |
| let g = if let Some(id) = ccx.tcx().hir.as_local_node_id(def_id) { |
| |
| let llty = type_of::type_of(ccx, ty); |
| let (g, attrs) = match ccx.tcx().hir.get(id) { |
| hir_map::NodeItem(&hir::Item { |
| ref attrs, span, node: hir::ItemStatic(..), .. |
| }) => { |
| let sym = ccx.symbol_map() |
| .get(TransItem::Static(id)) |
| .expect("Local statics should always be in the SymbolMap"); |
| |
| let defined_in_current_codegen_unit = ccx.codegen_unit() |
| .items() |
| .contains_key(&TransItem::Static(id)); |
| assert!(!defined_in_current_codegen_unit); |
| |
| if declare::get_declared_value(ccx, sym).is_some() { |
| span_bug!(span, "trans: Conflicting symbol names for static?"); |
| } |
| |
| let g = declare::define_global(ccx, sym, llty).unwrap(); |
| |
| (g, attrs) |
| } |
| |
| hir_map::NodeForeignItem(&hir::ForeignItem { |
| ref attrs, span, node: hir::ForeignItemStatic(..), .. |
| }) => { |
| let sym = instance.symbol_name(ccx.shared()); |
| let g = if let Some(name) = |
| attr::first_attr_value_str_by_name(&attrs, "linkage") { |
| // If this is a static with a linkage specified, then we need to handle |
| // it a little specially. The typesystem prevents things like &T and |
| // extern "C" fn() from being non-null, so we can't just declare a |
| // static and call it a day. Some linkages (like weak) will make it such |
| // that the static actually has a null value. |
| let linkage = match base::llvm_linkage_by_name(&name.as_str()) { |
| Some(linkage) => linkage, |
| None => { |
| ccx.sess().span_fatal(span, "invalid linkage specified"); |
| } |
| }; |
| let llty2 = match ty.sty { |
| ty::TyRawPtr(ref mt) => type_of::type_of(ccx, mt.ty), |
| _ => { |
| ccx.sess().span_fatal(span, "must have type `*const T` or `*mut T`"); |
| } |
| }; |
| unsafe { |
| // Declare a symbol `foo` with the desired linkage. |
| let g1 = declare::declare_global(ccx, &sym, llty2); |
| llvm::LLVMRustSetLinkage(g1, linkage); |
| |
| // Declare an internal global `extern_with_linkage_foo` which |
| // is initialized with the address of `foo`. If `foo` is |
| // discarded during linking (for example, if `foo` has weak |
| // linkage and there are no definitions), then |
| // `extern_with_linkage_foo` will instead be initialized to |
| // zero. |
| let mut real_name = "_rust_extern_with_linkage_".to_string(); |
| real_name.push_str(&sym); |
| let g2 = declare::define_global(ccx, &real_name, llty).unwrap_or_else(||{ |
| ccx.sess().span_fatal(span, |
| &format!("symbol `{}` is already defined", &sym)) |
| }); |
| llvm::LLVMRustSetLinkage(g2, llvm::Linkage::InternalLinkage); |
| llvm::LLVMSetInitializer(g2, g1); |
| g2 |
| } |
| } else { |
| // Generate an external declaration. |
| declare::declare_global(ccx, &sym, llty) |
| }; |
| |
| (g, attrs) |
| } |
| |
| item => bug!("get_static: expected static, found {:?}", item) |
| }; |
| |
| for attr in attrs { |
| if attr.check_name("thread_local") { |
| llvm::set_thread_local(g, true); |
| } |
| } |
| |
| g |
| } else { |
| let sym = instance.symbol_name(ccx.shared()); |
| |
| // 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 g = declare::declare_global(ccx, &sym, type_of::type_of(ccx, 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 ccx.tcx().get_attrs(def_id).iter() { |
| if attr.check_name("thread_local") { |
| llvm::set_thread_local(g, true); |
| } |
| } |
| if ccx.use_dll_storage_attrs() && !ccx.sess().cstore.is_foreign_item(def_id) { |
| // This item is external but not foreign, i.e. it originates from an external Rust |
| // crate. Since we don't know whether this crate will be linked dynamically or |
| // statically in the final application, we always mark such symbols as 'dllimport'. |
| // If final linkage happens to be static, we rely on compiler-emitted __imp_ stubs to |
| // make things work. |
| unsafe { |
| llvm::LLVMSetDLLStorageClass(g, llvm::DLLStorageClass::DllImport); |
| } |
| } |
| g |
| }; |
| |
| if ccx.use_dll_storage_attrs() && ccx.sess().cstore.is_dllimport_foreign_item(def_id) { |
| // For foreign (native) libs we know the exact storage type to use. |
| unsafe { |
| llvm::LLVMSetDLLStorageClass(g, llvm::DLLStorageClass::DllImport); |
| } |
| } |
| ccx.instances().borrow_mut().insert(instance, g); |
| ccx.statics().borrow_mut().insert(g, def_id); |
| g |
| } |
| |
| pub fn trans_static(ccx: &CrateContext, |
| m: hir::Mutability, |
| id: ast::NodeId, |
| attrs: &[ast::Attribute]) |
| -> Result<ValueRef, ConstEvalErr> { |
| unsafe { |
| let def_id = ccx.tcx().hir.local_def_id(id); |
| let g = get_static(ccx, def_id); |
| |
| let v = ::mir::trans_static_initializer(ccx, def_id)?; |
| |
| // 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 mut val_llty = val_ty(v); |
| let v = if val_llty == Type::i1(ccx) { |
| val_llty = Type::i8(ccx); |
| llvm::LLVMConstZExt(v, val_llty.to_ref()) |
| } else { |
| v |
| }; |
| |
| let ty = ccx.tcx().item_type(def_id); |
| let llty = type_of::type_of(ccx, ty); |
| let g = if val_llty == llty { |
| g |
| } else { |
| // If we created the global with the wrong type, |
| // correct the type. |
| let empty_string = CString::new("").unwrap(); |
| let name_str_ref = CStr::from_ptr(llvm::LLVMGetValueName(g)); |
| let name_string = CString::new(name_str_ref.to_bytes()).unwrap(); |
| llvm::LLVMSetValueName(g, empty_string.as_ptr()); |
| let new_g = llvm::LLVMRustGetOrInsertGlobal( |
| ccx.llmod(), name_string.as_ptr(), val_llty.to_ref()); |
| // To avoid breaking any invariants, we leave around the old |
| // global for the moment; we'll replace all references to it |
| // with the new global later. (See base::trans_crate.) |
| ccx.statics_to_rauw().borrow_mut().push((g, new_g)); |
| new_g |
| }; |
| llvm::LLVMSetAlignment(g, type_of::align_of(ccx, ty)); |
| llvm::LLVMSetInitializer(g, v); |
| |
| // As an optimization, all shared statics which do not have interior |
| // mutability are placed into read-only memory. |
| if m != hir::MutMutable { |
| let tcontents = ty.type_contents(ccx.tcx()); |
| if !tcontents.interior_unsafe() { |
| llvm::LLVMSetGlobalConstant(g, llvm::True); |
| } |
| } |
| |
| debuginfo::create_global_var_metadata(ccx, id, g); |
| |
| if attr::contains_name(attrs, |
| "thread_local") { |
| llvm::set_thread_local(g, true); |
| } |
| |
| base::set_link_section(ccx, g, attrs); |
| |
| Ok(g) |
| } |
| } |
