Auto merge of #51590 - bjorn3:codegen_llvm_extract, r=alexcrichton

Mostly fix metadata_only backend and extract some code out of rustc_codegen_llvm

Removes dependency on the `ar` crate and removes the `llvm.enabled` config option in favour of setting `rust.codegen-backends` to `[]`.

15 files changed, 30 insertions, 110 deletions

diff --git a/src/Cargo.lock b/src/Cargo.lock
index 7297d8a8299..d91a165e537 100644
--- a/src/Cargo.lock
+++ b/src/Cargo.lock
@@ -58,11 +58,6 @@ dependencies = [
 ]
 
 [[package]]
-name = "ar"
-version = "0.3.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-
-[[package]]
 name = "arena"
 version = "0.0.0"
 dependencies = [
@@ -2031,7 +2026,6 @@ dependencies = [
 name = "rustc_codegen_utils"
 version = "0.0.0"
 dependencies = [
- "ar 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "flate2 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
@@ -2072,7 +2066,6 @@ dependencies = [
 name = "rustc_driver"
 version = "0.0.0"
 dependencies = [
- "ar 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "arena 0.0.0",
  "env_logger 0.5.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "graphviz 0.0.0",
@@ -3077,7 +3070,6 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum aho-corasick 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)" = "f0ba20154ea1f47ce2793322f049c5646cc6d0fa9759d5f333f286e507bf8080"
 "checksum ammonia 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fd4c682378117e4186a492b2252b9537990e1617f44aed9788b9a1149de45477"
 "checksum ansi_term 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ee49baf6cb617b853aa8d93bf420db2383fab46d314482ca2803b40d5fde979b"
-"checksum ar 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "35c7a5669cb64f085739387e1308b74e6d44022464b7f1b63bbd4ceb6379ec31"
 "checksum arrayvec 0.4.7 (registry+https://github.com/rust-lang/crates.io-index)" = "a1e964f9e24d588183fcb43503abda40d288c8657dfc27311516ce2f05675aef"
 "checksum assert_cli 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "98589b0e465a6c510d95fceebd365bb79bedece7f6e18a480897f2015f85ec51"
 "checksum atty 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)" = "2fc4a1aa4c24c0718a250f0681885c1af91419d242f29eb8f2ab28502d80dbd1"
diff --git a/src/librustc/lib.rs b/src/librustc/lib.rs
index d8efb582eaa..8050522d066 100644
--- a/src/librustc/lib.rs
+++ b/src/librustc/lib.rs
@@ -162,6 +162,7 @@ pub mod util {
     pub mod ppaux;
     pub mod nodemap;
     pub mod fs;
+    pub mod time_graph;
 }
 
 // A private module so that macro-expanded idents like
diff --git a/src/librustc_codegen_llvm/time_graph.rs b/src/librustc/util/time_graph.rs
index a8502682a80..a8502682a80 100644
--- a/src/librustc_codegen_llvm/time_graph.rs
+++ b/src/librustc/util/time_graph.rs
diff --git a/src/librustc_codegen_llvm/base.rs b/src/librustc_codegen_llvm/base.rs
index a4709739a23..f9d84319433 100644
--- a/src/librustc_codegen_llvm/base.rs
+++ b/src/librustc_codegen_llvm/base.rs
@@ -56,6 +56,7 @@ use builder::{Builder, MemFlags};
 use callee;
 use common::{C_bool, C_bytes_in_context, C_i32, C_usize};
 use rustc_mir::monomorphize::collector::{self, MonoItemCollectionMode};
+use rustc_mir::monomorphize::item::DefPathBasedNames;
 use common::{self, C_struct_in_context, C_array, val_ty};
 use consts;
 use context::{self, CodegenCx};
@@ -67,7 +68,7 @@ use monomorphize::Instance;
 use monomorphize::partitioning::{self, PartitioningStrategy, CodegenUnit, CodegenUnitExt};
 use rustc_codegen_utils::symbol_names_test;
 use time_graph;
-use mono_item::{MonoItem, BaseMonoItemExt, MonoItemExt, DefPathBasedNames};
+use mono_item::{MonoItem, BaseMonoItemExt, MonoItemExt};
 use type_::Type;
 use type_of::LayoutLlvmExt;
 use rustc::util::nodemap::{FxHashMap, FxHashSet, DefIdSet};
@@ -92,7 +93,7 @@ use syntax::ast;
 
 use mir::operand::OperandValue;
 
-pub use rustc_codegen_utils::check_for_rustc_errors_attr;
+use rustc_codegen_utils::check_for_rustc_errors_attr;
 
 pub struct StatRecorder<'a, 'tcx: 'a> {
     cx: &'a CodegenCx<'a, 'tcx>,
diff --git a/src/librustc_codegen_llvm/lib.rs b/src/librustc_codegen_llvm/lib.rs
index b11b0c7abe8..93d9ce1e98a 100644
--- a/src/librustc_codegen_llvm/lib.rs
+++ b/src/librustc_codegen_llvm/lib.rs
@@ -76,6 +76,7 @@ use rustc::middle::lang_items::LangItem;
 use rustc::session::{Session, CompileIncomplete};
 use rustc::session::config::{OutputFilenames, OutputType, PrintRequest};
 use rustc::ty::{self, TyCtxt};
+use rustc::util::time_graph;
 use rustc::util::nodemap::{FxHashSet, FxHashMap};
 use rustc_mir::monomorphize;
 use rustc_codegen_utils::codegen_backend::CodegenBackend;
@@ -114,7 +115,6 @@ mod llvm_util;
 mod metadata;
 mod meth;
 mod mir;
-mod time_graph;
 mod mono_item;
 mod type_;
 mod type_of;
@@ -368,7 +368,7 @@ struct CodegenResults {
     crate_info: CrateInfo,
 }
 
-// Misc info we load from metadata to persist beyond the tcx
+/// Misc info we load from metadata to persist beyond the tcx
 struct CrateInfo {
     panic_runtime: Option<CrateNum>,
     compiler_builtins: Option<CrateNum>,
diff --git a/src/librustc_codegen_llvm/mono_item.rs b/src/librustc_codegen_llvm/mono_item.rs
index c4a23ac653c..2f7b27b85af 100644
--- a/src/librustc_codegen_llvm/mono_item.rs
+++ b/src/librustc_codegen_llvm/mono_item.rs
@@ -33,7 +33,6 @@ use std::fmt;
 
 pub use rustc::mir::mono::MonoItem;
 
-pub use rustc_mir::monomorphize::item::*;
 pub use rustc_mir::monomorphize::item::MonoItemExt as BaseMonoItemExt;
 
 pub trait MonoItemExt<'a, 'tcx>: fmt::Debug + BaseMonoItemExt<'a, 'tcx> {
diff --git a/src/librustc_codegen_llvm/type_of.rs b/src/librustc_codegen_llvm/type_of.rs
index 88b75ff9c09..bfabf65dfd8 100644
--- a/src/librustc_codegen_llvm/type_of.rs
+++ b/src/librustc_codegen_llvm/type_of.rs
@@ -16,7 +16,7 @@ use rustc::ty::{self, Ty, TypeFoldable};
 use rustc::ty::layout::{self, Align, LayoutOf, Size, TyLayout};
 use rustc_target::spec::PanicStrategy;
 use rustc_target::abi::FloatTy;
-use mono_item::DefPathBasedNames;
+use rustc_mir::monomorphize::item::DefPathBasedNames;
 use type_::Type;
 
 use std::fmt::Write;
diff --git a/src/librustc_codegen_utils/Cargo.toml b/src/librustc_codegen_utils/Cargo.toml
index 690fb260390..30f533285dd 100644
--- a/src/librustc_codegen_utils/Cargo.toml
+++ b/src/librustc_codegen_utils/Cargo.toml
@@ -10,7 +10,6 @@ crate-type = ["dylib"]
 test = false
 
 [dependencies]
-ar = "0.3.0"
 flate2 = "1.0"
 log = "0.4"
 
diff --git a/src/librustc_codegen_utils/codegen_backend.rs b/src/librustc_codegen_utils/codegen_backend.rs
index 8ba6f30cf16..3cbf176d98b 100644
--- a/src/librustc_codegen_utils/codegen_backend.rs
+++ b/src/librustc_codegen_utils/codegen_backend.rs
@@ -22,15 +22,13 @@
 #![feature(box_syntax)]
 
 use std::any::Any;
-use std::io::prelude::*;
-use std::io::{self, Cursor};
+use std::io::{self, Write};
 use std::fs::File;
 use std::path::Path;
-use std::sync::mpsc;
+use std::sync::{mpsc, Arc};
 
 use rustc_data_structures::owning_ref::OwningRef;
 use rustc_data_structures::sync::Lrc;
-use ar::{Archive, Builder, Header};
 use flate2::Compression;
 use flate2::write::DeflateEncoder;
 
@@ -81,89 +79,21 @@ pub trait CodegenBackend {
     ) -> Result<(), CompileIncomplete>;
 }
 
-pub struct DummyCodegenBackend;
-
-impl CodegenBackend for DummyCodegenBackend {
-    fn metadata_loader(&self) -> Box<MetadataLoader + Sync> {
-        box DummyMetadataLoader(())
-    }
-
-    fn provide(&self, _providers: &mut Providers) {
-        bug!("DummyCodegenBackend::provide");
-    }
-
-    fn provide_extern(&self, _providers: &mut Providers) {
-        bug!("DummyCodegenBackend::provide_extern");
-    }
-
-    fn codegen_crate<'a, 'tcx>(
-        &self,
-        _tcx: TyCtxt<'a, 'tcx, 'tcx>,
-        _rx: mpsc::Receiver<Box<Any + Send>>
-    ) -> Box<Any> {
-        bug!("DummyCodegenBackend::codegen_backend");
-    }
-
-    fn join_codegen_and_link(
-        &self,
-        _ongoing_codegen: Box<Any>,
-        _sess: &Session,
-        _dep_graph: &DepGraph,
-        _outputs: &OutputFilenames,
-    ) -> Result<(), CompileIncomplete> {
-        bug!("DummyCodegenBackend::join_codegen_and_link");
-    }
-}
-
-pub struct DummyMetadataLoader(());
-
-impl MetadataLoader for DummyMetadataLoader {
-    fn get_rlib_metadata(
-        &self,
-        _target: &Target,
-        _filename: &Path
-    ) -> Result<MetadataRef, String> {
-        bug!("DummyMetadataLoader::get_rlib_metadata");
-    }
-
-    fn get_dylib_metadata(
-        &self,
-        _target: &Target,
-        _filename: &Path
-    ) -> Result<MetadataRef, String> {
-        bug!("DummyMetadataLoader::get_dylib_metadata");
-    }
-}
-
 pub struct NoLlvmMetadataLoader;
 
 impl MetadataLoader for NoLlvmMetadataLoader {
     fn get_rlib_metadata(&self, _: &Target, filename: &Path) -> Result<MetadataRef, String> {
-        let file = File::open(filename)
+        let mut file = File::open(filename)
             .map_err(|e| format!("metadata file open err: {:?}", e))?;
-        let mut archive = Archive::new(file);
-
-        while let Some(entry_result) = archive.next_entry() {
-            let mut entry = entry_result
-                .map_err(|e| format!("metadata section read err: {:?}", e))?;
-            if entry.header().identifier() == "rust.metadata.bin" {
-                let mut buf = Vec::new();
-                io::copy(&mut entry, &mut buf).unwrap();
-                let buf: OwningRef<Vec<u8>, [u8]> = OwningRef::new(buf).into();
-                return Ok(rustc_erase_owner!(buf.map_owner_box()));
-            }
-        }
 
-        Err("Couldn't find metadata section".to_string())
+        let mut buf = Vec::new();
+        io::copy(&mut file, &mut buf).unwrap();
+        let buf: OwningRef<Vec<u8>, [u8]> = OwningRef::new(buf).into();
+        return Ok(rustc_erase_owner!(buf.map_owner_box()));
     }
 
-    fn get_dylib_metadata(
-        &self,
-        _target: &Target,
-        _filename: &Path,
-    ) -> Result<MetadataRef, String> {
-        // FIXME: Support reading dylibs from llvm enabled rustc
-        self.get_rlib_metadata(_target, _filename)
+    fn get_dylib_metadata(&self, target: &Target, filename: &Path) -> Result<MetadataRef, String> {
+        self.get_rlib_metadata(target, filename)
     }
 }
 
@@ -205,8 +135,13 @@ impl CodegenBackend for MetadataOnlyCodegenBackend {
         providers.target_features_whitelist = |_tcx, _cnum| {
             Lrc::new(FxHashMap()) // Just a dummy
         };
+        providers.is_reachable_non_generic = |_tcx, _defid| true;
+        providers.exported_symbols = |_tcx, _crate| Arc::new(Vec::new());
+        providers.wasm_custom_sections = |_tcx, _crate| Lrc::new(Vec::new());
+    }
+    fn provide_extern(&self, providers: &mut Providers) {
+        providers.is_reachable_non_generic = |_tcx, _defid| true;
     }
-    fn provide_extern(&self, _providers: &mut Providers) {}
 
     fn codegen_crate<'a, 'tcx>(
         &self,
@@ -225,7 +160,8 @@ impl CodegenBackend for MetadataOnlyCodegenBackend {
                 collector::MonoItemCollectionMode::Eager
             ).0.iter()
         );
-        ::rustc::middle::dependency_format::calculate(tcx);
+        // FIXME: Fix this
+        // ::rustc::middle::dependency_format::calculate(tcx);
         let _ = tcx.link_args(LOCAL_CRATE);
         let _ = tcx.native_libraries(LOCAL_CRATE);
         for mono_item in
@@ -280,9 +216,8 @@ impl CodegenBackend for MetadataOnlyCodegenBackend {
             } else {
                 &ongoing_codegen.metadata.raw_data
             };
-            let mut builder = Builder::new(File::create(&output_name).unwrap());
-            let header = Header::new("rust.metadata.bin".to_string(), metadata.len() as u64);
-            builder.append(&header, Cursor::new(metadata)).unwrap();
+            let mut file = File::create(&output_name).unwrap();
+            file.write_all(metadata).unwrap();
         }
 
         sess.abort_if_errors();
diff --git a/src/librustc_codegen_utils/lib.rs b/src/librustc_codegen_utils/lib.rs
index d09e8f4845e..f59cf5832fc 100644
--- a/src/librustc_codegen_utils/lib.rs
+++ b/src/librustc_codegen_utils/lib.rs
@@ -25,7 +25,6 @@
 
 #![recursion_limit="256"]
 
-extern crate ar;
 extern crate flate2;
 #[macro_use]
 extern crate log;
@@ -39,8 +38,6 @@ extern crate syntax;
 extern crate syntax_pos;
 #[macro_use] extern crate rustc_data_structures;
 
-pub extern crate rustc as __rustc;
-
 use rustc::ty::TyCtxt;
 
 pub mod link;
diff --git a/src/librustc_driver/Cargo.toml b/src/librustc_driver/Cargo.toml
index 5b75912c18f..7a020f331e5 100644
--- a/src/librustc_driver/Cargo.toml
+++ b/src/librustc_driver/Cargo.toml
@@ -37,5 +37,3 @@ serialize = { path = "../libserialize" }
 syntax = { path = "../libsyntax" }
 syntax_ext = { path = "../libsyntax_ext" }
 syntax_pos = { path = "../libsyntax_pos" }
-
-ar = "0.3.0"
diff --git a/src/test/run-make-fulldeps/hotplug_codegen_backend/Makefile b/src/test/run-make-fulldeps/hotplug_codegen_backend/Makefile
index 2ddf3aa5439..e203ec2737f 100644
--- a/src/test/run-make-fulldeps/hotplug_codegen_backend/Makefile
+++ b/src/test/run-make-fulldeps/hotplug_codegen_backend/Makefile
@@ -4,6 +4,6 @@ all:
 	/bin/echo || exit 0 # This test requires /bin/echo to exist
 	$(RUSTC) the_backend.rs --crate-name the_backend --crate-type dylib \
 		-o $(TMPDIR)/the_backend.dylib
-	$(RUSTC) some_crate.rs --crate-name some_crate --crate-type bin -o $(TMPDIR)/some_crate \
+	$(RUSTC) some_crate.rs --crate-name some_crate --crate-type lib -o $(TMPDIR)/some_crate \
 		-Z codegen-backend=$(TMPDIR)/the_backend.dylib -Z unstable-options
 	grep -x "This has been \"compiled\" successfully." $(TMPDIR)/some_crate
diff --git a/src/test/run-make-fulldeps/hotplug_codegen_backend/some_crate.rs b/src/test/run-make-fulldeps/hotplug_codegen_backend/some_crate.rs
index 26ffce01b2e..bfa8b6b3ef6 100644
--- a/src/test/run-make-fulldeps/hotplug_codegen_backend/some_crate.rs
+++ b/src/test/run-make-fulldeps/hotplug_codegen_backend/some_crate.rs
@@ -8,6 +8,5 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-fn main() {
-    ::std::process::exit(1);
-}
+#![feature(no_core)]
+#![no_core]
diff --git a/src/test/run-make-fulldeps/hotplug_codegen_backend/the_backend.rs b/src/test/run-make-fulldeps/hotplug_codegen_backend/the_backend.rs
index 439bc017fee..a3cd033f863 100644
--- a/src/test/run-make-fulldeps/hotplug_codegen_backend/the_backend.rs
+++ b/src/test/run-make-fulldeps/hotplug_codegen_backend/the_backend.rs
@@ -63,7 +63,7 @@ impl CodegenBackend for TheBackend {
         let crate_name = ongoing_codegen.downcast::<Symbol>()
             .expect("in join_codegen_and_link: ongoing_codegen is not a Symbol");
         for &crate_type in sess.opts.crate_types.iter() {
-            if crate_type != CrateType::CrateTypeExecutable {
+            if crate_type != CrateType::CrateTypeRlib {
                 sess.fatal(&format!("Crate type is {:?}", crate_type));
             }
             let output_name =
diff --git a/src/tools/tidy/src/deps.rs b/src/tools/tidy/src/deps.rs
index dedf42fecbb..942d27202ec 100644
--- a/src/tools/tidy/src/deps.rs
+++ b/src/tools/tidy/src/deps.rs
@@ -59,7 +59,6 @@ static WHITELIST_CRATES: &'static [CrateVersion] = &[
 /// Whitelist of crates rustc is allowed to depend on. Avoid adding to the list if possible.
 static WHITELIST: &'static [Crate] = &[
     Crate("aho-corasick"),
-    Crate("ar"),
     Crate("arrayvec"),
     Crate("atty"),
     Crate("backtrace"),