Deduplicate linkage checking code for statics
Signed-off-by: Gabriel Smith <ga29smith@gmail.com>
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a20262c069
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@ -20,12 +20,14 @@ use monomorphize::MonoItem;
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use common::{CodegenCx, val_ty};
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use declare;
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use monomorphize::Instance;
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use syntax_pos::Span;
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use syntax_pos::symbol::LocalInternedString;
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use type_::Type;
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use type_of::LayoutLlvmExt;
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use rustc::ty;
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use rustc::ty::{self, Ty};
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use rustc::ty::layout::{Align, LayoutOf};
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use rustc::hir::{self, CodegenFnAttrFlags};
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use rustc::hir::{self, CodegenFnAttrs, CodegenFnAttrFlags};
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use std::ffi::{CStr, CString};
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@ -146,47 +148,8 @@ pub fn get_static(cx: &CodegenCx, def_id: DefId) -> ValueRef {
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hir_map::NodeForeignItem(&hir::ForeignItem {
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ref attrs, span, node: hir::ForeignItemKind::Static(..), ..
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}) => {
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let g = if let Some(linkage) = cx.tcx.codegen_fn_attrs(def_id).linkage {
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debug!("get_static: sym={} linkage={:?}", sym, linkage);
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// If this is a static with a linkage specified, then we need to handle
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// it a little specially. The typesystem prevents things like &T and
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// extern "C" fn() from being non-null, so we can't just declare a
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// static and call it a day. Some linkages (like weak) will make it such
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// that the static actually has a null value.
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let llty2 = match ty.sty {
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ty::TyRawPtr(ref mt) => cx.layout_of(mt.ty).llvm_type(cx),
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_ => {
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cx.sess().span_fatal(span, "must have type `*const T` or `*mut T`");
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}
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};
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unsafe {
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// Declare a symbol `foo` with the desired linkage.
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let g1 = declare::declare_global(cx, &sym, llty2);
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llvm::LLVMRustSetLinkage(g1, base::linkage_to_llvm(linkage));
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// Declare an internal global `extern_with_linkage_foo` which
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// is initialized with the address of `foo`. If `foo` is
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// discarded during linking (for example, if `foo` has weak
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// linkage and there are no definitions), then
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// `extern_with_linkage_foo` will instead be initialized to
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// zero.
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let mut real_name = "_rust_extern_with_linkage_".to_string();
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real_name.push_str(&sym);
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let g2 = declare::define_global(cx, &real_name, llty).unwrap_or_else(||{
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cx.sess().span_fatal(span,
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&format!("symbol `{}` is already defined", &sym))
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});
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llvm::LLVMRustSetLinkage(g2, llvm::Linkage::InternalLinkage);
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llvm::LLVMSetInitializer(g2, g1);
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g2
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}
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} else {
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// Generate an external declaration.
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declare::declare_global(cx, &sym, llty)
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};
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(g, attrs)
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let fn_attrs = cx.tcx.codegen_fn_attrs(def_id);
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(check_and_apply_linkage(cx, &fn_attrs, ty, sym, Some(span)), attrs)
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}
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item => bug!("get_static: expected static, found {:?}", item)
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@ -205,47 +168,8 @@ pub fn get_static(cx: &CodegenCx, def_id: DefId) -> ValueRef {
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// FIXME(nagisa): perhaps the map of externs could be offloaded to llvm somehow?
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debug!("get_static: sym={} item_attr={:?}", sym, cx.tcx.item_attrs(def_id));
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let codegen_fn_attrs = cx.tcx.codegen_fn_attrs(def_id);
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let llty = cx.layout_of(ty).llvm_type(cx);
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let g = if let Some(linkage) = codegen_fn_attrs.linkage {
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debug!("get_static: sym={} linkage={:?}", sym, linkage);
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// If this is a static with a linkage specified, then we need to handle
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// it a little specially. The typesystem prevents things like &T and
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// extern "C" fn() from being non-null, so we can't just declare a
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// static and call it a day. Some linkages (like weak) will make it such
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// that the static actually has a null value.
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let llty2 = match ty.sty {
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ty::TyRawPtr(ref mt) => cx.layout_of(mt.ty).llvm_type(cx),
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_ => {
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bug!("must have type `*const T` or `*mut T`")
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}
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};
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unsafe {
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// Declare a symbol `foo` with the desired linkage.
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let g1 = declare::declare_global(cx, &sym, llty2);
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llvm::LLVMRustSetLinkage(g1, base::linkage_to_llvm(linkage));
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// Declare an internal global `extern_with_linkage_foo` which
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// is initialized with the address of `foo`. If `foo` is
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// discarded during linking (for example, if `foo` has weak
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// linkage and there are no definitions), then
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// `extern_with_linkage_foo` will instead be initialized to
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// zero.
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let mut real_name = "_rust_extern_with_linkage_".to_string();
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real_name.push_str(&sym);
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let g2 = declare::define_global(cx, &real_name, llty).unwrap_or_else(||{
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bug!("symbol `{}` is already defined", &sym)
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});
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llvm::LLVMRustSetLinkage(g2, llvm::Linkage::InternalLinkage);
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llvm::LLVMSetInitializer(g2, g1);
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g2
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}
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} else {
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// Generate an external declaration.
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// FIXME(nagisa): investigate whether it can be changed into define_global
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declare::declare_global(cx, &sym, llty)
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};
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let attrs = cx.tcx.codegen_fn_attrs(def_id);
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let g = check_and_apply_linkage(cx, &attrs, ty, sym, None);
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// Thread-local statics in some other crate need to *always* be linked
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// against in a thread-local fashion, so we need to be sure to apply the
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@ -253,7 +177,7 @@ pub fn get_static(cx: &CodegenCx, def_id: DefId) -> ValueRef {
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// don't do this then linker errors can be generated where the linker
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// complains that one object files has a thread local version of the
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// symbol and another one doesn't.
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if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::THREAD_LOCAL) {
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if attrs.flags.contains(CodegenFnAttrFlags::THREAD_LOCAL) {
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llvm::set_thread_local_mode(g, cx.tls_model);
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}
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@ -289,6 +213,66 @@ pub fn get_static(cx: &CodegenCx, def_id: DefId) -> ValueRef {
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g
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}
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fn check_and_apply_linkage<'tcx>(
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cx: &CodegenCx<'_, 'tcx>,
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attrs: &CodegenFnAttrs,
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ty: Ty<'tcx>,
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sym: LocalInternedString,
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span: Option<Span>
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) -> ValueRef {
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let llty = cx.layout_of(ty).llvm_type(cx);
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if let Some(linkage) = attrs.linkage {
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debug!("get_static: sym={} linkage={:?}", sym, linkage);
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// If this is a static with a linkage specified, then we need to handle
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// it a little specially. The typesystem prevents things like &T and
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// extern "C" fn() from being non-null, so we can't just declare a
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// static and call it a day. Some linkages (like weak) will make it such
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// that the static actually has a null value.
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let llty2 = match ty.sty {
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ty::TyRawPtr(ref mt) => cx.layout_of(mt.ty).llvm_type(cx),
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_ => {
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if span.is_some() {
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cx.sess().span_fatal(span.unwrap(), "must have type `*const T` or `*mut T`")
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} else {
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bug!("must have type `*const T` or `*mut T`")
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}
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}
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};
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unsafe {
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// Declare a symbol `foo` with the desired linkage.
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let g1 = declare::declare_global(cx, &sym, llty2);
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llvm::LLVMRustSetLinkage(g1, base::linkage_to_llvm(linkage));
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// Declare an internal global `extern_with_linkage_foo` which
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// is initialized with the address of `foo`. If `foo` is
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// discarded during linking (for example, if `foo` has weak
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// linkage and there are no definitions), then
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// `extern_with_linkage_foo` will instead be initialized to
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// zero.
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let mut real_name = "_rust_extern_with_linkage_".to_string();
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real_name.push_str(&sym);
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let g2 = declare::define_global(cx, &real_name, llty).unwrap_or_else(||{
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if span.is_some() {
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cx.sess().span_fatal(
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span.unwrap(),
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&format!("symbol `{}` is already defined", &sym)
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)
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} else {
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bug!("symbol `{}` is already defined", &sym)
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}
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});
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llvm::LLVMRustSetLinkage(g2, llvm::Linkage::InternalLinkage);
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llvm::LLVMSetInitializer(g2, g1);
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g2
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}
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} else {
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// Generate an external declaration.
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// FIXME(nagisa): investigate whether it can be changed into define_global
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declare::declare_global(cx, &sym, llty)
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}
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}
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pub fn codegen_static<'a, 'tcx>(
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cx: &CodegenCx<'a, 'tcx>,
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def_id: DefId,
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