From d4dec4701a5e5e6fb4f66c838b9646bc1c1f711b Mon Sep 17 00:00:00 2001 From: Alex Crichton Date: Fri, 6 Jun 2014 17:48:46 -0700 Subject: [PATCH] rustc: Preserve reachable extern fns with LTO All rust functions are internal implementation details with respect to the ABI exposed by crates, but extern fns are public components of the ABI and shouldn't be stripped. This commit serializes reachable extern fns to metadata, so when LTO is performed all of their symbols are not stripped. Closes #14500 --- src/librustc/metadata/common.rs | 3 +++ src/librustc/metadata/csearch.rs | 7 +++++++ src/librustc/metadata/decoder.rs | 14 ++++++++++++++ src/librustc/metadata/encoder.rs | 25 +++++++++++++++++++++++++ src/librustc/middle/trans/base.rs | 11 +++++++++++ src/test/run-make/issue-14500/Makefile | 14 ++++++++++++++ src/test/run-make/issue-14500/bar.rs | 11 +++++++++++ src/test/run-make/issue-14500/foo.c | 16 ++++++++++++++++ src/test/run-make/issue-14500/foo.rs | 12 ++++++++++++ src/test/run-make/lto-smoke-c/Makefile | 15 +-------------- src/test/run-make/tools.mk | 14 ++++++++++++++ 11 files changed, 128 insertions(+), 14 deletions(-) create mode 100644 src/test/run-make/issue-14500/Makefile create mode 100644 src/test/run-make/issue-14500/bar.rs create mode 100644 src/test/run-make/issue-14500/foo.c create mode 100644 src/test/run-make/issue-14500/foo.rs diff --git a/src/librustc/metadata/common.rs b/src/librustc/metadata/common.rs index 8aeef3dca98..6287683c1a1 100644 --- a/src/librustc/metadata/common.rs +++ b/src/librustc/metadata/common.rs @@ -209,6 +209,9 @@ pub static tag_dylib_dependency_formats: uint = 0x67; pub static tag_method_argument_names: uint = 0x8e; pub static tag_method_argument_name: uint = 0x8f; +pub static tag_reachable_extern_fns: uint = 0x90; +pub static tag_reachable_extern_fn_id: uint = 0x91; + #[deriving(Clone, Show)] pub struct LinkMeta { pub crateid: CrateId, diff --git a/src/librustc/metadata/csearch.rs b/src/librustc/metadata/csearch.rs index 74a804763e8..c7ad74dce57 100644 --- a/src/librustc/metadata/csearch.rs +++ b/src/librustc/metadata/csearch.rs @@ -314,3 +314,10 @@ pub fn get_method_arg_names(cstore: &cstore::CStore, did: ast::DefId) let cdata = cstore.get_crate_data(did.krate); decoder::get_method_arg_names(&*cdata, did.node) } + +pub fn get_reachable_extern_fns(cstore: &cstore::CStore, cnum: ast::CrateNum) + -> Vec +{ + let cdata = cstore.get_crate_data(cnum); + decoder::get_reachable_extern_fns(&*cdata) +} diff --git a/src/librustc/metadata/decoder.rs b/src/librustc/metadata/decoder.rs index 6469462734e..c67b5bf1a60 100644 --- a/src/librustc/metadata/decoder.rs +++ b/src/librustc/metadata/decoder.rs @@ -1325,3 +1325,17 @@ pub fn get_method_arg_names(cdata: Cmd, id: ast::NodeId) -> Vec { } return ret; } + +pub fn get_reachable_extern_fns(cdata: Cmd) -> Vec { + let mut ret = Vec::new(); + let items = reader::get_doc(ebml::Doc::new(cdata.data()), + tag_reachable_extern_fns); + reader::tagged_docs(items, tag_reachable_extern_fn_id, |doc| { + ret.push(ast::DefId { + krate: cdata.cnum, + node: reader::doc_as_u32(doc), + }); + true + }); + return ret; +} diff --git a/src/librustc/metadata/encoder.rs b/src/librustc/metadata/encoder.rs index cd2f3360f83..37cb75e4697 100644 --- a/src/librustc/metadata/encoder.rs +++ b/src/librustc/metadata/encoder.rs @@ -75,6 +75,7 @@ pub struct EncodeParams<'a> { pub link_meta: &'a LinkMeta, pub cstore: &'a cstore::CStore, pub encode_inlined_item: EncodeInlinedItem<'a>, + pub reachable: &'a NodeSet, } pub struct EncodeContext<'a> { @@ -87,6 +88,7 @@ pub struct EncodeContext<'a> { pub cstore: &'a cstore::CStore, pub encode_inlined_item: RefCell>, pub type_abbrevs: tyencode::abbrev_map, + pub reachable: &'a NodeSet, } fn encode_name(ebml_w: &mut Encoder, name: Name) { @@ -1702,6 +1704,26 @@ fn encode_misc_info(ecx: &EncodeContext, ebml_w.end_tag(); } +fn encode_reachable_extern_fns(ecx: &EncodeContext, ebml_w: &mut Encoder) { + ebml_w.start_tag(tag_reachable_extern_fns); + + for id in ecx.reachable.iter() { + match ecx.tcx.map.find(*id) { + Some(ast_map::NodeItem(i)) => { + match i.node { + ast::ItemFn(_, _, abi, _, _) if abi != abi::Rust => { + ebml_w.wr_tagged_u32(tag_reachable_extern_fn_id, *id); + } + _ => {} + } + } + _ => {} + } + } + + ebml_w.end_tag(); +} + fn encode_crate_dep(ebml_w: &mut Encoder, dep: decoder::CrateDep) { ebml_w.start_tag(tag_crate_dep); @@ -1801,6 +1823,7 @@ fn encode_metadata_inner(wr: &mut MemWriter, parms: EncodeParams, krate: &Crate) encode_inlined_item, link_meta, non_inlineable_statics, + reachable, .. } = parms; let ecx = EncodeContext { @@ -1813,6 +1836,7 @@ fn encode_metadata_inner(wr: &mut MemWriter, parms: EncodeParams, krate: &Crate) cstore: cstore, encode_inlined_item: RefCell::new(encode_inlined_item), type_abbrevs: RefCell::new(HashMap::new()), + reachable: reachable, }; let mut ebml_w = writer::Encoder::new(wr); @@ -1864,6 +1888,7 @@ fn encode_metadata_inner(wr: &mut MemWriter, parms: EncodeParams, krate: &Crate) // Encode miscellaneous info. i = ebml_w.writer.tell().unwrap(); encode_misc_info(&ecx, krate, &mut ebml_w); + encode_reachable_extern_fns(&ecx, &mut ebml_w); stats.misc_bytes = ebml_w.writer.tell().unwrap() - i; // Encode and index the items. diff --git a/src/librustc/middle/trans/base.rs b/src/librustc/middle/trans/base.rs index 9be07eaaca9..09f5d2a3507 100644 --- a/src/librustc/middle/trans/base.rs +++ b/src/librustc/middle/trans/base.rs @@ -2238,6 +2238,7 @@ pub fn crate_ctxt_to_encode_parms<'r>(cx: &'r CrateContext, ie: encoder::EncodeI link_meta: &cx.link_meta, cstore: &cx.sess().cstore, encode_inlined_item: ie, + reachable: &cx.reachable, } } @@ -2374,6 +2375,16 @@ pub fn trans_crate(krate: ast::Crate, ccx.item_symbols.borrow().find(id).map(|s| s.to_string()) }).collect(); + // For the purposes of LTO, we add to the reachable set all of the upstream + // reachable extern fns. These functions are all part of the public ABI of + // the final product, so LTO needs to preserve them. + ccx.sess().cstore.iter_crate_data(|cnum, _| { + let syms = csearch::get_reachable_extern_fns(&ccx.sess().cstore, cnum); + reachable.extend(syms.move_iter().map(|did| { + csearch::get_symbol(&ccx.sess().cstore, did) + })); + }); + // Make sure that some other crucial symbols are not eliminated from the // module. This includes the main function, the crate map (used for debug // log settings and I/O), and finally the curious rust_stack_exhausted diff --git a/src/test/run-make/issue-14500/Makefile b/src/test/run-make/issue-14500/Makefile new file mode 100644 index 00000000000..c1087b0f55e --- /dev/null +++ b/src/test/run-make/issue-14500/Makefile @@ -0,0 +1,14 @@ +-include ../tools.mk + +# Test to make sure that reachable extern fns are always available in final +# productcs, including when LTO is used. In this test, the `foo` crate has a +# reahable symbol, and is a dependency of the `bar` crate. When the `bar` crate +# is compiled with LTO, it shouldn't strip the symbol from `foo`, and that's the +# only way that `foo.c` will successfully compile. + +all: + $(RUSTC) foo.rs --crate-type=rlib + $(RUSTC) bar.rs --crate-type=staticlib -Zlto -L. -o $(TMPDIR)/libbar.a + $(CC) foo.c -lbar -o $(call RUN_BINFILE,foo) $(EXTRACFLAGS) + $(call RUN,foo) + diff --git a/src/test/run-make/issue-14500/bar.rs b/src/test/run-make/issue-14500/bar.rs new file mode 100644 index 00000000000..4b4916fe96d --- /dev/null +++ b/src/test/run-make/issue-14500/bar.rs @@ -0,0 +1,11 @@ +// Copyright 2014 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 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +extern crate foo; diff --git a/src/test/run-make/issue-14500/foo.c b/src/test/run-make/issue-14500/foo.c new file mode 100644 index 00000000000..25098ac479d --- /dev/null +++ b/src/test/run-make/issue-14500/foo.c @@ -0,0 +1,16 @@ +// Copyright 2014 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 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +extern void foo(); + +int main() { + foo(); + return 0; +} diff --git a/src/test/run-make/issue-14500/foo.rs b/src/test/run-make/issue-14500/foo.rs new file mode 100644 index 00000000000..ceca907403f --- /dev/null +++ b/src/test/run-make/issue-14500/foo.rs @@ -0,0 +1,12 @@ +// Copyright 2014 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 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +#[no_mangle] +pub extern fn foo() {} diff --git a/src/test/run-make/lto-smoke-c/Makefile b/src/test/run-make/lto-smoke-c/Makefile index 49a04ce42a0..9b44c3e582a 100644 --- a/src/test/run-make/lto-smoke-c/Makefile +++ b/src/test/run-make/lto-smoke-c/Makefile @@ -1,23 +1,10 @@ -include ../tools.mk -ifdef IS_WINDOWS - EXTRAFLAGS := -else -ifeq ($(shell uname),Darwin) -else -ifeq ($(shell uname),FreeBSD) - EXTRAFLAGS := -lm -lpthread -lgcc_s -else - EXTRAFLAGS := -lm -lrt -ldl -lpthread -endif -endif -endif - # Apparently older versions of GCC segfault if -g is passed... CC := $(CC:-g=) all: $(RUSTC) foo.rs -Z lto ln -s $(call STATICLIB,foo-*) $(call STATICLIB,foo) - $(CC) bar.c -lfoo -o $(call RUN_BINFILE,bar) $(EXTRAFLAGS) -lstdc++ + $(CC) bar.c -lfoo -o $(call RUN_BINFILE,bar) $(EXTRACFLAGS) -lstdc++ $(call RUN,bar) diff --git a/src/test/run-make/tools.mk b/src/test/run-make/tools.mk index dedd739052c..c9c4c455e4f 100644 --- a/src/test/run-make/tools.mk +++ b/src/test/run-make/tools.mk @@ -53,6 +53,20 @@ RPATH_LINK_SEARCH = -Wl,-rpath-link=$(1) endif endif +# Extra flags needed to compile a working executable with the standard library +ifdef IS_WINDOWS + EXTRACFLAGS := +else +ifeq ($(shell uname),Darwin) +else +ifeq ($(shell uname),FreeBSD) + EXTRACFLAGS := -lm -lpthread -lgcc_s +else + EXTRACFLAGS := -lm -lrt -ldl -lpthread +endif +endif +endif + REMOVE_DYLIBS = rm $(TMPDIR)/$(call DYLIB_GLOB,$(1)) REMOVE_RLIBS = rm $(TMPDIR)/$(call RLIB_GLOB,$(1))