Allow writing metadata without llvm

.gitignore

@@ -103,3 +103,6 @@ version.texi
 .cargo
 !src/vendor/**
 /src/target/
+
+no_llvm_build
+

src/bootstrap/compile.rs

@@ -104,7 +104,11 @@ impl Step for Std {
 
         let out_dir = build.cargo_out(compiler, Mode::Libstd, target);
         build.clear_if_dirty(&out_dir, &builder.rustc(compiler));
-        let mut cargo = builder.cargo(compiler, Mode::Libstd, target, "build");
+        let mut cargo = if compiler.stage == 0 {
+            builder.cargo(compiler, Mode::Libstd, target, "build")
+        }else{
+            builder.cargo(compiler, Mode::Libstd, target, "check")
+        };
         std_cargo(build, &compiler, target, &mut cargo);
         run_cargo(build,
                 &mut cargo,
@@ -161,6 +165,7 @@ pub fn std_cargo(build: &Build,
         // missing
         // We also only build the runtimes when --enable-sanitizers (or its
         // config.toml equivalent) is used
+        //cargo.env("RUST_FLAGS", "-Zno-trans");
         cargo.env("LLVM_CONFIG", build.llvm_config(target));
     }
 

src/librustc_driver/driver.rs

@@ -77,6 +77,8 @@ pub fn compile_input(sess: &Session,
                      addl_plugins: Option<Vec<String>>,
                      control: &CompileController) -> CompileResult {
     use rustc_trans::back::write::OngoingCrateTranslation;
+    use rustc::session::config::CrateType;
+
     macro_rules! controller_entry_point {
         ($point: ident, $tsess: expr, $make_state: expr, $phase_result: expr) => {{
             let state = &mut $make_state;
@@ -94,7 +96,6 @@ pub fn compile_input(sess: &Session,
     }
 
     if cfg!(not(feature="llvm")) {
-        use rustc::session::config::CrateType;
         if !sess.opts.debugging_opts.no_trans && sess.opts.output_types.should_trans() {
             sess.err("LLVM is not supported by this rustc. Please use -Z no-trans to compile")
         }

src/librustc_driver/lib.rs

@@ -25,6 +25,8 @@
 #![feature(rustc_diagnostic_macros)]
 #![feature(set_stdio)]
 
+#[cfg(not(feature="llvm"))]
+extern crate ar;
 extern crate arena;
 extern crate getopts;
 extern crate graphviz;
@@ -157,7 +159,6 @@ pub use rustc_trans::LlvmMetadataLoader as MetadataLoader;
 
 #[cfg(not(feature="llvm"))]
 mod no_llvm_metadata_loader {
-    extern crate ar;
     extern crate owning_ref;
 
     use rustc::middle::cstore::MetadataLoader as MetadataLoaderTrait;
@@ -166,7 +167,7 @@ mod no_llvm_metadata_loader {
     use std::fs::File;
     use std::path::Path;
 
-    use self::ar::Archive;
+    use ar::Archive;
     use self::owning_ref::{OwningRef, ErasedBoxRef};
 
     pub struct NoLLvmMetadataLoader;

src/librustc_trans/back/link.rs

@@ -89,15 +89,8 @@ pub const RLIB_BYTECODE_OBJECT_V1_DATA_OFFSET: usize =
     RLIB_BYTECODE_OBJECT_V1_DATASIZE_OFFSET + 8;
 
 pub use self::rustc_trans_utils::link::{find_crate_name, filename_for_input,
-                                        default_output_for_target, invalid_output_for_target};
-
-pub fn build_link_meta(crate_hash: Fingerprint) -> LinkMeta {
-    let r = LinkMeta {
-        crate_hash: Svh::new(crate_hash.to_smaller_hash()),
-    };
-    info!("{:?}", r);
-    return r;
-}
+                                        default_output_for_target, invalid_output_for_target,
+                                        build_link_meta};
 
 // The third parameter is for env vars, used on windows to set up the
 // path for MSVC to find its DLLs, and gcc to find its bundled

src/librustc_trans/base.rs

@@ -938,6 +938,8 @@ pub fn find_exported_symbols(tcx: TyCtxt) -> NodeSet {
 pub fn trans_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                              rx: mpsc::Receiver<Box<Any + Send>>)
                              -> OngoingCrateTranslation {
+    use back::link::rustc_trans_utils::find_exported_symbols;
+
     check_for_rustc_errors_attr(tcx);
 
 

src/librustc_trans_utils/Cargo.toml

@@ -10,6 +10,8 @@ crate-type = ["dylib"]
 test = false
 
 [dependencies]
+log = "0.3"
 rustc = { path = "../librustc" }
+rustc_incremental = { path = "../librustc_incremental" }
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }

src/librustc_trans_utils/lib.rs

@@ -29,8 +29,68 @@
 
 #![cfg_attr(stage0, feature(const_fn))]
 
+#[macro_use]
+extern crate log;
 extern crate rustc;
+extern crate rustc_incremental;
 extern crate syntax;
 extern crate syntax_pos;
 
+use rustc::ty::TyCtxt;
+use rustc::hir;
+use rustc::hir::map as hir_map;
+use rustc::util::nodemap::NodeSet;
+
+use syntax::attr;
+
 pub mod link;
+
+/// The context provided lists a set of reachable ids as calculated by
+/// middle::reachable, but this contains far more ids and symbols than we're
+/// actually exposing from the object file. This function will filter the set in
+/// the context to the set of ids which correspond to symbols that are exposed
+/// from the object file being generated.
+///
+/// This list is later used by linkers to determine the set of symbols needed to
+/// be exposed from a dynamic library and it's also encoded into the metadata.
+pub fn find_exported_symbols(tcx: TyCtxt, reachable: &NodeSet) -> NodeSet {
+    reachable.iter().cloned().filter(|&id| {
+        // Next, we want to ignore some FFI functions that are not exposed from
+        // this crate. Reachable FFI functions can be lumped into two
+        // categories:
+        //
+        // 1. Those that are included statically via a static library
+        // 2. Those included otherwise (e.g. dynamically or via a framework)
+        //
+        // Although our LLVM module is not literally emitting code for the
+        // statically included symbols, it's an export of our library which
+        // needs to be passed on to the linker and encoded in the metadata.
+        //
+        // As a result, if this id is an FFI item (foreign item) then we only
+        // let it through if it's included statically.
+        match tcx.hir.get(id) {
+            hir_map::NodeForeignItem(..) => {
+                let def_id = tcx.hir.local_def_id(id);
+                tcx.sess.cstore.is_statically_included_foreign_item(def_id)
+            }
+
+            // Only consider nodes that actually have exported symbols.
+            hir_map::NodeItem(&hir::Item {
+                node: hir::ItemStatic(..), .. }) |
+            hir_map::NodeItem(&hir::Item {
+                node: hir::ItemFn(..), .. }) |
+            hir_map::NodeImplItem(&hir::ImplItem {
+                node: hir::ImplItemKind::Method(..), .. }) => {
+                let def_id = tcx.hir.local_def_id(id);
+                let generics = tcx.generics_of(def_id);
+                let attributes = tcx.get_attrs(def_id);
+                (generics.parent_types == 0 && generics.types.is_empty()) &&
+                // Functions marked with #[inline] are only ever translated
+                // with "internal" linkage and are never exported.
+                !attr::requests_inline(&attributes)
+            }
+
+            _ => false
+        }
+    }).collect()
+}

src/librustc_trans_utils/link.rs

@@ -10,11 +10,23 @@
 
 use rustc::session::config::{self, OutputFilenames, Input, OutputType};
 use rustc::session::Session;
-use rustc::middle::cstore;
+use rustc::middle::cstore::{self, LinkMeta};
+use rustc::dep_graph::{DepKind, DepNode};
+use rustc::hir::svh::Svh;
+use rustc_incremental::IncrementalHashesMap;
 use std::path::PathBuf;
 use syntax::ast;
 use syntax_pos::Span;
 
+pub fn build_link_meta(incremental_hashes_map: &IncrementalHashesMap) -> LinkMeta {
+    let krate_dep_node = &DepNode::new_no_params(DepKind::Krate);
+    let r = LinkMeta {
+        crate_hash: Svh::new(incremental_hashes_map[krate_dep_node].to_smaller_hash()),
+    };
+    info!("{:?}", r);
+    return r;
+}
+
 pub fn find_crate_name(sess: Option<&Session>,
                        attrs: &[ast::Attribute],
                        input: &Input) -> String {