Auto merge of #56732 - Zoxc:rustc-interface, r=oli-obk

Make the rustc driver and interface demand driven

This introduces a new crate `rustc_interface` which is the canonical interface for creating and using the compiler. It allows you to access a `Compiler` type in a closure and that types have methods to run passes on demand. The interesting parts are found [here (defining the queries)](https://github.com/Zoxc/rust/blob/rustc-interface/src/librustc_interface/queries.rs#L78) and [here (methods to create a `Compiler`)](https://github.com/Zoxc/rust/blob/rustc-interface/src/librustc_interface/interface.rs).

cc @rust-lang/compiler @rust-lang/dev-tools @rust-lang/rustdoc

Author: bors

Diff for: src/librustc/ich/impls_ty.rs

@@ -946,11 +946,6 @@ impl_stable_hash_for!(struct ty::CrateInherentImpls {
     inherent_impls
 });
 
-impl_stable_hash_for!(enum crate::session::CompileIncomplete {
-    Stopped,
-    Errored(error_reported)
-});
-
 impl_stable_hash_for!(struct crate::util::common::ErrorReported {});
 
 impl_stable_hash_for!(tuple_struct crate::middle::reachable::ReachableSet {

Diff for: src/librustc/session/config.rs

@@ -11,6 +11,7 @@ use rustc_target::spec::{Target, TargetTriple};
 use crate::lint;
 use crate::middle::cstore;
 
+use syntax;
 use syntax::ast::{self, IntTy, UintTy, MetaItemKind};
 use syntax::source_map::{FileName, FilePathMapping};
 use syntax::edition::{Edition, EDITION_NAME_LIST, DEFAULT_EDITION};
@@ -1494,6 +1495,15 @@ pub fn default_configuration(sess: &Session) -> ast::CrateConfig {
     ret
 }
 
+/// Converts the crate cfg! configuration from String to Symbol.
+/// `rustc_interface::interface::Config` accepts this in the compiler configuration,
+/// but the symbol interner is not yet set up then, so we must convert it later.
+pub fn to_crate_config(cfg: FxHashSet<(String, Option<String>)>) -> ast::CrateConfig {
+    cfg.into_iter()
+       .map(|(a, b)| (Symbol::intern(&a), b.map(|b| Symbol::intern(&b))))
+       .collect()
+}
+
 pub fn build_configuration(sess: &Session, mut user_cfg: ast::CrateConfig) -> ast::CrateConfig {
     // Combine the configuration requested by the session (command line) with
     // some default and generated configuration items
@@ -1800,10 +1810,9 @@ pub fn rustc_optgroups() -> Vec<RustcOptGroup> {
 }
 
 // Convert strings provided as --cfg [cfgspec] into a crate_cfg
-pub fn parse_cfgspecs(cfgspecs: Vec<String>) -> ast::CrateConfig {
-    cfgspecs
-        .into_iter()
-        .map(|s| {
+pub fn parse_cfgspecs(cfgspecs: Vec<String>) -> FxHashSet<(String, Option<String>)> {
+    syntax::with_globals(move || {
+        let cfg = cfgspecs.into_iter().map(|s| {
             let sess = parse::ParseSess::new(FilePathMapping::empty());
             let filename = FileName::cfg_spec_source_code(&s);
             let mut parser = parse::new_parser_from_source_str(&sess, filename, s.to_string());
@@ -1835,8 +1844,11 @@ pub fn parse_cfgspecs(cfgspecs: Vec<String>) -> ast::CrateConfig {
             }
 
             error!(r#"expected `key` or `key="value"`"#);
-        })
-        .collect::<ast::CrateConfig>()
+        }).collect::<ast::CrateConfig>();
+        cfg.into_iter().map(|(a, b)| {
+            (a.to_string(), b.map(|b| b.to_string()))
+        }).collect()
+    })
 }
 
 pub fn get_cmd_lint_options(matches: &getopts::Matches,
@@ -1864,7 +1876,7 @@ pub fn get_cmd_lint_options(matches: &getopts::Matches,
 
 pub fn build_session_options_and_crate_config(
     matches: &getopts::Matches,
-) -> (Options, ast::CrateConfig) {
+) -> (Options, FxHashSet<(String, Option<String>)>) {
     let color = match matches.opt_str("color").as_ref().map(|s| &s[..]) {
         Some("auto") => ColorConfig::Auto,
         Some("always") => ColorConfig::Always,
@@ -2590,7 +2602,11 @@ mod tests {
     use getopts;
     use crate::lint;
     use crate::middle::cstore;
-    use crate::session::config::{build_configuration, build_session_options_and_crate_config};
+    use crate::session::config::{
+        build_configuration,
+        build_session_options_and_crate_config,
+        to_crate_config
+    };
     use crate::session::config::{LtoCli, LinkerPluginLto};
     use crate::session::build_session;
     use crate::session::search_paths::SearchPath;
@@ -2631,7 +2647,7 @@ mod tests {
             let registry = errors::registry::Registry::new(&[]);
             let (sessopts, cfg) = build_session_options_and_crate_config(matches);
             let sess = build_session(sessopts, None, registry);
-            let cfg = build_configuration(&sess, cfg);
+            let cfg = build_configuration(&sess, to_crate_config(cfg));
             assert!(cfg.contains(&(Symbol::intern("test"), None)));
         });
     }
@@ -2649,7 +2665,7 @@ mod tests {
             let registry = errors::registry::Registry::new(&[]);
             let (sessopts, cfg) = build_session_options_and_crate_config(matches);
             let sess = build_session(sessopts, None, registry);
-            let cfg = build_configuration(&sess, cfg);
+            let cfg = build_configuration(&sess, to_crate_config(cfg));
             let mut test_items = cfg.iter().filter(|&&(name, _)| name == "test");
             assert!(test_items.next().is_some());
             assert!(test_items.next().is_none());

Diff for: src/librustc/session/mod.rs

@@ -311,7 +311,7 @@ impl Session {
     pub fn abort_if_errors(&self) {
         self.diagnostic().abort_if_errors();
     }
-    pub fn compile_status(&self) -> Result<(), CompileIncomplete> {
+    pub fn compile_status(&self) -> Result<(), ErrorReported> {
         compile_result_from_err_count(self.err_count())
     }
     pub fn track_errors<F, T>(&self, f: F) -> Result<T, ErrorReported>
@@ -1124,7 +1124,7 @@ pub fn build_session_with_source_map(
     build_session_(sopts, local_crate_source_file, diagnostic_handler, source_map, lint_caps)
 }
 
-pub fn build_session_(
+fn build_session_(
     sopts: config::Options,
     local_crate_source_file: Option<PathBuf>,
     span_diagnostic: errors::Handler,
@@ -1334,22 +1334,12 @@ pub fn early_warn(output: config::ErrorOutputType, msg: &str) {
     handler.emit(&MultiSpan::new(), msg, errors::Level::Warning);
 }
 
-#[derive(Copy, Clone, Debug)]
-pub enum CompileIncomplete {
-    Stopped,
-    Errored(ErrorReported),
-}
-impl From<ErrorReported> for CompileIncomplete {
-    fn from(err: ErrorReported) -> CompileIncomplete {
-        CompileIncomplete::Errored(err)
-    }
-}
-pub type CompileResult = Result<(), CompileIncomplete>;
+pub type CompileResult = Result<(), ErrorReported>;
 
 pub fn compile_result_from_err_count(err_count: usize) -> CompileResult {
     if err_count == 0 {
         Ok(())
     } else {
-        Err(CompileIncomplete::Errored(ErrorReported))
+        Err(ErrorReported)
     }
 }

Diff for: src/librustc/ty/context.rs

@@ -78,15 +78,13 @@ use crate::hir;
 pub struct AllArenas<'tcx> {
     pub global: WorkerLocal<GlobalArenas<'tcx>>,
     pub interner: SyncDroplessArena,
-    global_ctxt: Option<GlobalCtxt<'tcx>>,
 }
 
 impl<'tcx> AllArenas<'tcx> {
     pub fn new() -> Self {
         AllArenas {
             global: WorkerLocal::new(|_| GlobalArenas::default()),
             interner: SyncDroplessArena::default(),
-            global_ctxt: None,
         }
     }
 }
@@ -1182,20 +1180,19 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
     /// to the context. The closure enforces that the type context and any interned
     /// value (types, substs, etc.) can only be used while `ty::tls` has a valid
     /// reference to the context, to allow formatting values that need it.
-    pub fn create_and_enter<F, R>(s: &'tcx Session,
-                                  cstore: &'tcx CrateStoreDyn,
-                                  local_providers: ty::query::Providers<'tcx>,
-                                  extern_providers: ty::query::Providers<'tcx>,
-                                  arenas: &'tcx mut AllArenas<'tcx>,
-                                  resolutions: ty::Resolutions,
-                                  hir: hir_map::Map<'tcx>,
-                                  on_disk_query_result_cache: query::OnDiskCache<'tcx>,
-                                  crate_name: &str,
-                                  tx: mpsc::Sender<Box<dyn Any + Send>>,
-                                  output_filenames: &OutputFilenames,
-                                  f: F) -> R
-                                  where F: for<'b> FnOnce(TyCtxt<'b, 'tcx, 'tcx>) -> R
-    {
+    pub fn create_global_ctxt(
+        s: &'tcx Session,
+        cstore: &'tcx CrateStoreDyn,
+        local_providers: ty::query::Providers<'tcx>,
+        extern_providers: ty::query::Providers<'tcx>,
+        arenas: &'tcx AllArenas<'tcx>,
+        resolutions: ty::Resolutions,
+        hir: hir_map::Map<'tcx>,
+        on_disk_query_result_cache: query::OnDiskCache<'tcx>,
+        crate_name: &str,
+        tx: mpsc::Sender<Box<dyn Any + Send>>,
+        output_filenames: &OutputFilenames,
+    ) -> GlobalCtxt<'tcx> {
         let data_layout = TargetDataLayout::parse(&s.target.target).unwrap_or_else(|err| {
             s.fatal(&err);
         });
@@ -1247,7 +1244,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                                      Lrc::new(StableVec::new(v)));
         }
 
-        arenas.global_ctxt = Some(GlobalCtxt {
+        GlobalCtxt {
             sess: s,
             cstore,
             global_arenas: &arenas.global,
@@ -1293,15 +1290,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
             alloc_map: Lock::new(interpret::AllocMap::new()),
             tx_to_llvm_workers: Lock::new(tx),
             output_filenames: Arc::new(output_filenames.clone()),
-        });
-
-        let gcx = arenas.global_ctxt.as_ref().unwrap();
-
-        let r = tls::enter_global(gcx, f);
-
-        gcx.queries.record_computed_queries(s);
-
-        r
+        }
     }
 
     pub fn consider_optimizing<T: Fn() -> String>(&self, msg: T) -> bool {
@@ -1985,31 +1974,29 @@ pub mod tls {
     pub fn enter_global<'gcx, F, R>(gcx: &'gcx GlobalCtxt<'gcx>, f: F) -> R
         where F: FnOnce(TyCtxt<'gcx, 'gcx, 'gcx>) -> R
     {
-        with_thread_locals(|| {
-            // Update GCX_PTR to indicate there's a GlobalCtxt available
-            GCX_PTR.with(|lock| {
-                *lock.lock() = gcx as *const _ as usize;
-            });
-            // Set GCX_PTR back to 0 when we exit
-            let _on_drop = OnDrop(move || {
-                GCX_PTR.with(|lock| *lock.lock() = 0);
-            });
+        // Update GCX_PTR to indicate there's a GlobalCtxt available
+        GCX_PTR.with(|lock| {
+            *lock.lock() = gcx as *const _ as usize;
+        });
+        // Set GCX_PTR back to 0 when we exit
+        let _on_drop = OnDrop(move || {
+            GCX_PTR.with(|lock| *lock.lock() = 0);
+        });
 
-            let tcx = TyCtxt {
-                gcx,
-                interners: &gcx.global_interners,
-                dummy: PhantomData,
-            };
-            let icx = ImplicitCtxt {
-                tcx,
-                query: None,
-                diagnostics: None,
-                layout_depth: 0,
-                task_deps: None,
-            };
-            enter_context(&icx, |_| {
-                f(tcx)
-            })
+        let tcx = TyCtxt {
+            gcx,
+            interners: &gcx.global_interners,
+            dummy: PhantomData,
+        };
+        let icx = ImplicitCtxt {
+            tcx,
+            query: None,
+            diagnostics: None,
+            layout_depth: 0,
+            task_deps: None,
+        };
+        enter_context(&icx, |_| {
+            f(tcx)
         })
     }
 

Diff for: src/librustc/ty/mod.rs

@@ -71,7 +71,7 @@ pub use self::binding::BindingMode;
 pub use self::binding::BindingMode::*;
 
 pub use self::context::{TyCtxt, FreeRegionInfo, GlobalArenas, AllArenas, tls, keep_local};
-pub use self::context::{Lift, TypeckTables, CtxtInterners};
+pub use self::context::{Lift, TypeckTables, CtxtInterners, GlobalCtxt};
 pub use self::context::{
     UserTypeAnnotationIndex, UserType, CanonicalUserType,
     CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, ResolvedOpaqueTy,

Diff for: src/librustc_codegen_llvm/lib.rs

@@ -63,11 +63,12 @@ use std::sync::{mpsc, Arc};
 use rustc::dep_graph::DepGraph;
 use rustc::middle::allocator::AllocatorKind;
 use rustc::middle::cstore::{EncodedMetadata, MetadataLoader};
-use rustc::session::{Session, CompileIncomplete};
+use rustc::session::Session;
 use rustc::session::config::{OutputFilenames, OutputType, PrintRequest, OptLevel};
 use rustc::ty::{self, TyCtxt};
 use rustc::util::time_graph;
 use rustc::util::profiling::ProfileCategory;
+use rustc::util::common::ErrorReported;
 use rustc_mir::monomorphize;
 use rustc_codegen_ssa::ModuleCodegen;
 use rustc_codegen_utils::codegen_backend::CodegenBackend;
@@ -311,7 +312,7 @@ impl CodegenBackend for LlvmCodegenBackend {
         sess: &Session,
         dep_graph: &DepGraph,
         outputs: &OutputFilenames,
-    ) -> Result<(), CompileIncomplete>{
+    ) -> Result<(), ErrorReported>{
         use rustc::util::common::time;
         let (codegen_results, work_products) =
             ongoing_codegen.downcast::

Diff for: src/librustc_codegen_utils/codegen_backend.rs

@@ -21,7 +21,8 @@ use flate2::write::DeflateEncoder;
 
 use syntax::symbol::Symbol;
 use rustc::hir::def_id::LOCAL_CRATE;
-use rustc::session::{Session, CompileIncomplete};
+use rustc::session::Session;
+use rustc::util::common::ErrorReported;
 use rustc::session::config::{CrateType, OutputFilenames, PrintRequest};
 use rustc::ty::TyCtxt;
 use rustc::ty::query::Providers;
@@ -61,7 +62,7 @@ pub trait CodegenBackend {
         sess: &Session,
         dep_graph: &DepGraph,
         outputs: &OutputFilenames,
-    ) -> Result<(), CompileIncomplete>;
+    ) -> Result<(), ErrorReported>;
 }
 
 pub struct NoLlvmMetadataLoader;
@@ -163,7 +164,7 @@ impl CodegenBackend for MetadataOnlyCodegenBackend {
         sess: &Session,
         _dep_graph: &DepGraph,
         outputs: &OutputFilenames,
-    ) -> Result<(), CompileIncomplete> {
+    ) -> Result<(), ErrorReported> {
         let ongoing_codegen = ongoing_codegen.downcast::<OngoingCodegen>()
             .expect("Expected MetadataOnlyCodegenBackend's OngoingCodegen, found Box<dyn Any>");
         for &crate_type in sess.opts.crate_types.iter() {