Auto merge of #33473 - michaelwoerister:split-cratecontext, r=nikomat…

…sakis

Preparatory refactorings for collector-driven trans.

This is a set of refactorings that allows to do translation item collection and partitioning before LocalCrateContext instances or LLVM modules are generated. As a consequence we can now create LocalCrateContexts already with knowledge of the codegen unit it will be used for. This is a preparation step for driving trans by the results of codegen unit partitioning.

src/librustc_trans/back/write.rs

@@ -639,7 +639,8 @@ pub fn run_passes(sess: &Session,
     }
 
     // Sanity check
-    assert!(trans.modules.len() == sess.opts.cg.codegen_units);
+    assert!(trans.modules.len() == sess.opts.cg.codegen_units ||
+            sess.opts.debugging_opts.incremental.is_some());
 
     let tm = create_target_machine(sess);
 

src/librustc_trans/base.rs

@@ -68,7 +68,7 @@ use common::{node_id_type, fulfill_obligation};
 use common::{type_is_immediate, type_is_zero_size, val_ty};
 use common;
 use consts;
-use context::SharedCrateContext;
+use context::{SharedCrateContext, CrateContextList};
 use controlflow;
 use datum;
 use debuginfo::{self, DebugLoc, ToDebugLoc};
@@ -81,7 +81,7 @@ use machine::{llalign_of_min, llsize_of, llsize_of_real};
 use meth;
 use mir;
 use monomorphize::{self, Instance};
-use partitioning::{self, PartitioningStrategy, InstantiationMode};
+use partitioning::{self, PartitioningStrategy, InstantiationMode, CodegenUnit};
 use symbol_names_test;
 use tvec;
 use type_::Type;
@@ -664,7 +664,7 @@ pub fn coerce_unsized_into<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
     }
 }
 
-pub fn custom_coerce_unsize_info<'ccx, 'tcx>(ccx: &CrateContext<'ccx, 'tcx>,
+pub fn custom_coerce_unsize_info<'scx, 'tcx>(scx: &SharedCrateContext<'scx, 'tcx>,
                                              source_ty: Ty<'tcx>,
                                              target_ty: Ty<'tcx>)
                                              -> CustomCoerceUnsized {
@@ -674,13 +674,13 @@ pub fn custom_coerce_unsize_info<'ccx, 'tcx>(ccx: &CrateContext<'ccx, 'tcx>,
                                    subst::VecPerParamSpace::empty());
 
     let trait_ref = ty::Binder(ty::TraitRef {
-        def_id: ccx.tcx().lang_items.coerce_unsized_trait().unwrap(),
-        substs: ccx.tcx().mk_substs(trait_substs)
+        def_id: scx.tcx().lang_items.coerce_unsized_trait().unwrap(),
+        substs: scx.tcx().mk_substs(trait_substs)
     });
 
-    match fulfill_obligation(ccx, DUMMY_SP, trait_ref) {
+    match fulfill_obligation(scx, DUMMY_SP, trait_ref) {
         traits::VtableImpl(traits::VtableImplData { impl_def_id, .. }) => {
-            ccx.tcx().custom_coerce_unsized_kind(impl_def_id)
+            scx.tcx().custom_coerce_unsized_kind(impl_def_id)
         }
         vtable => {
             bug!("invalid CoerceUnsized vtable: {:?}", vtable);
@@ -1824,7 +1824,7 @@ pub fn trans_closure<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
                                closure_env: closure::ClosureEnv) {
     ccx.stats().n_closures.set(ccx.stats().n_closures.get() + 1);
 
-    if collector::collecting_debug_information(ccx) {
+    if collector::collecting_debug_information(ccx.shared()) {
         ccx.record_translation_item_as_generated(TransItem::Fn(instance));
     }
 
@@ -2188,7 +2188,8 @@ pub fn update_linkage(ccx: &CrateContext,
             // `llval` is a translation of an item defined in a separate
             // compilation unit.  This only makes sense if there are at least
             // two compilation units.
-            assert!(ccx.sess().opts.cg.codegen_units > 1);
+            assert!(ccx.sess().opts.cg.codegen_units > 1 ||
+                    ccx.sess().opts.debugging_opts.incremental.is_some());
             // `llval` is a copy of something defined elsewhere, so use
             // `AvailableExternallyLinkage` to avoid duplicating code in the
             // output.
@@ -2524,7 +2525,7 @@ pub fn write_metadata<'a, 'tcx>(cx: &SharedCrateContext<'a, 'tcx>,
 
 /// Find any symbols that are defined in one compilation unit, but not declared
 /// in any other compilation unit.  Give these symbols internal linkage.
-fn internalize_symbols(cx: &SharedCrateContext, reachable: &HashSet<&str>) {
+fn internalize_symbols(cx: &CrateContextList, reachable: &HashSet<&str>) {
     unsafe {
         let mut declared = HashSet::new();
 
@@ -2579,12 +2580,12 @@ fn internalize_symbols(cx: &SharedCrateContext, reachable: &HashSet<&str>) {
 // when using MSVC linker.  We do this only for data, as linker can fix up
 // code references on its own.
 // See #26591, #27438
-fn create_imps(cx: &SharedCrateContext) {
+fn create_imps(cx: &CrateContextList) {
     // The x86 ABI seems to require that leading underscores are added to symbol
     // names, so we need an extra underscore on 32-bit. There's also a leading
     // '\x01' here which disables LLVM's symbol mangling (e.g. no extra
     // underscores added in front).
-    let prefix = if cx.sess().target.target.target_pointer_width == "32" {
+    let prefix = if cx.shared().sess().target.target.target_pointer_width == "32" {
         "\x01__imp__"
     } else {
         "\x01__imp_"
@@ -2661,10 +2662,10 @@ fn iter_functions(llmod: llvm::ModuleRef) -> ValueIter {
 ///
 /// 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 filter_reachable_ids(ccx: &SharedCrateContext) -> NodeSet {
-    ccx.reachable().iter().map(|x| *x).filter(|id| {
+pub fn filter_reachable_ids(scx: &SharedCrateContext) -> NodeSet {
+    scx.reachable().iter().map(|x| *x).filter(|id| {
         // First, only worry about nodes which have a symbol name
-        ccx.item_symbols().borrow().contains_key(id)
+        scx.item_symbols().borrow().contains_key(id)
     }).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
@@ -2679,9 +2680,9 @@ pub fn filter_reachable_ids(ccx: &SharedCrateContext) -> NodeSet {
         //
         // As a result, if this id is an FFI item (foreign item) then we only
         // let it through if it's included statically.
-        match ccx.tcx().map.get(id) {
+        match scx.tcx().map.get(id) {
             hir_map::NodeForeignItem(..) => {
-                ccx.sess().cstore.is_statically_included_foreign_item(id)
+                scx.sess().cstore.is_statically_included_foreign_item(id)
             }
             _ => true,
         }
@@ -2716,10 +2717,7 @@ pub fn trans_crate<'tcx>(tcx: &TyCtxt<'tcx>,
 
     let link_meta = link::build_link_meta(&tcx, name);
 
-    let codegen_units = tcx.sess.opts.cg.codegen_units;
-    let shared_ccx = SharedCrateContext::new(&link_meta.crate_name,
-                                             codegen_units,
-                                             tcx,
+    let shared_ccx = SharedCrateContext::new(tcx,
                                              &mir_map,
                                              export_map,
                                              Sha256::new(),
@@ -2728,9 +2726,15 @@ pub fn trans_crate<'tcx>(tcx: &TyCtxt<'tcx>,
                                              check_overflow,
                                              check_dropflag);
 
+    let codegen_units = collect_and_partition_translation_items(&shared_ccx);
+    let codegen_unit_count = codegen_units.len();
+    assert!(tcx.sess.opts.cg.codegen_units == codegen_unit_count ||
+            tcx.sess.opts.debugging_opts.incremental.is_some());
+
+    let crate_context_list = CrateContextList::new(&shared_ccx, codegen_units);
+
     {
-        let ccx = shared_ccx.get_ccx(0);
-        collect_translation_items(&ccx);
+        let ccx = crate_context_list.get_ccx(0);
 
         // Translate all items. See `TransModVisitor` for
         // details on why we walk in this particular way.
@@ -2740,12 +2744,12 @@ pub fn trans_crate<'tcx>(tcx: &TyCtxt<'tcx>,
             krate.visit_all_items(&mut TransModVisitor { ccx: &ccx });
         }
 
-        collector::print_collection_results(&ccx);
+        collector::print_collection_results(ccx.shared());
 
         symbol_names_test::report_symbol_names(&ccx);
     }
 
-    for ccx in shared_ccx.iter() {
+    for ccx in crate_context_list.iter() {
         if ccx.sess().opts.debuginfo != NoDebugInfo {
             debuginfo::finalize(&ccx);
         }
@@ -2794,7 +2798,7 @@ pub fn trans_crate<'tcx>(tcx: &TyCtxt<'tcx>,
         }
     }
 
-    let modules = shared_ccx.iter()
+    let modules = crate_context_list.iter()
         .map(|ccx| ModuleTranslation { llcx: ccx.llcx(), llmod: ccx.llmod() })
         .collect();
 
@@ -2820,14 +2824,14 @@ pub fn trans_crate<'tcx>(tcx: &TyCtxt<'tcx>,
         }
     }
 
-    if codegen_units > 1 {
-        internalize_symbols(&shared_ccx,
+    if codegen_unit_count > 1 {
+        internalize_symbols(&crate_context_list,
                             &reachable_symbols.iter().map(|x| &x[..]).collect());
     }
 
     if sess.target.target.options.is_like_msvc &&
        sess.crate_types.borrow().iter().any(|ct| *ct == config::CrateTypeRlib) {
-        create_imps(&shared_ccx);
+        create_imps(&crate_context_list);
     }
 
     let metadata_module = ModuleTranslation {
@@ -2912,10 +2916,11 @@ impl<'a, 'tcx, 'v> Visitor<'v> for TransItemsWithinModVisitor<'a, 'tcx> {
     }
 }
 
-fn collect_translation_items<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>) {
-    let time_passes = ccx.sess().time_passes();
+fn collect_and_partition_translation_items<'a, 'tcx>(scx: &SharedCrateContext<'a, 'tcx>)
+                                                     -> Vec<CodegenUnit<'tcx>> {
+    let time_passes = scx.sess().time_passes();
 
-    let collection_mode = match ccx.sess().opts.debugging_opts.print_trans_items {
+    let collection_mode = match scx.sess().opts.debugging_opts.print_trans_items {
         Some(ref s) => {
             let mode_string = s.to_lowercase();
             let mode_string = mode_string.trim();
@@ -2926,7 +2931,7 @@ fn collect_translation_items<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>) {
                     let message = format!("Unknown codegen-item collection mode '{}'. \
                                            Falling back to 'lazy' mode.",
                                            mode_string);
-                    ccx.sess().warn(&message);
+                    scx.sess().warn(&message);
                 }
 
                 TransItemCollectionMode::Lazy
@@ -2936,27 +2941,27 @@ fn collect_translation_items<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>) {
     };
 
     let (items, reference_map) = time(time_passes, "translation item collection", || {
-        collector::collect_crate_translation_items(&ccx, collection_mode)
+        collector::collect_crate_translation_items(scx, collection_mode)
     });
 
-    let strategy = if ccx.sess().opts.debugging_opts.incremental.is_some() {
+    let strategy = if scx.sess().opts.debugging_opts.incremental.is_some() {
         PartitioningStrategy::PerModule
     } else {
-        PartitioningStrategy::FixedUnitCount(ccx.sess().opts.cg.codegen_units)
+        PartitioningStrategy::FixedUnitCount(scx.sess().opts.cg.codegen_units)
     };
 
     let codegen_units = time(time_passes, "codegen unit partitioning", || {
-        partitioning::partition(ccx.tcx(),
+        partitioning::partition(scx.tcx(),
                                 items.iter().cloned(),
                                 strategy,
                                 &reference_map)
     });
 
-    if ccx.sess().opts.debugging_opts.print_trans_items.is_some() {
+    if scx.sess().opts.debugging_opts.print_trans_items.is_some() {
         let mut item_to_cgus = HashMap::new();
 
-        for cgu in codegen_units {
-            for (trans_item, linkage) in cgu.items {
+        for cgu in &codegen_units {
+            for (&trans_item, &linkage) in &cgu.items {
                 item_to_cgus.entry(trans_item)
                             .or_insert(Vec::new())
                             .push((cgu.name.clone(), linkage));
@@ -2966,7 +2971,7 @@ fn collect_translation_items<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>) {
         let mut item_keys: Vec<_> = items
             .iter()
             .map(|i| {
-                let mut output = i.to_string(ccx);
+                let mut output = i.to_string(scx.tcx());
                 output.push_str(" @@");
                 let mut empty = Vec::new();
                 let mut cgus = item_to_cgus.get_mut(i).unwrap_or(&mut empty);
@@ -3005,10 +3010,12 @@ fn collect_translation_items<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>) {
             println!("TRANS_ITEM {}", item);
         }
 
-        let mut ccx_map = ccx.translation_items().borrow_mut();
+        let mut ccx_map = scx.translation_items().borrow_mut();
 
         for cgi in items {
             ccx_map.insert(cgi, TransItemState::PredictedButNotGenerated);
         }
     }
+
+    codegen_units
 }

src/librustc_trans/callee.rs

@@ -156,7 +156,7 @@ impl<'tcx> Callee<'tcx> {
         let trait_id = method_item.container().id();
         let trait_ref = ty::Binder(substs.to_trait_ref(tcx, trait_id));
         let trait_ref = infer::normalize_associated_type(tcx, &trait_ref);
-        match common::fulfill_obligation(ccx, DUMMY_SP, trait_ref) {
+        match common::fulfill_obligation(ccx.shared(), DUMMY_SP, trait_ref) {
             traits::VtableImpl(vtable_impl) => {
                 let impl_did = vtable_impl.impl_def_id;
                 let mname = tcx.item_name(def_id);