Auto merge of #54356 - Xanewok:save-analysis-invocation, r=nrc

Emit used rustc invocation in the save-analysis file

Blocked on https://github.com/nrc/rls-data/pull/19. (I'm guessing it won't pass CI due to an out-of-tree git dependency)

This should allow RLS to recreate a Rust compilation build plan from the save-analysis files alone, which should be useful when fetching those from external build systems, most notably Buck now.

Also this includes some more potentially useful compilation-specific options (e.g. sysroot or the actual path to extern crates) but that's not required for the build plan bits.

cc @jsgf @alexcrichton

r? @nrc

9 files changed, 123 insertions, 25 deletions

diff --git a/src/Cargo.lock b/src/Cargo.lock
index 9a383a381d5..5a44b696a03 100644
--- a/src/Cargo.lock
+++ b/src/Cargo.lock
@@ -2373,6 +2373,7 @@ dependencies = [
  "rls-span 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
  "rustc-serialize 0.3.24 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc_codegen_utils 0.0.0",
  "rustc_data_structures 0.0.0",
  "rustc_target 0.0.0",
  "rustc_typeck 0.0.0",
diff --git a/src/librustc_codegen_llvm/back/link.rs b/src/librustc_codegen_llvm/back/link.rs
index 8248385c127..ce52fe00b0e 100644
--- a/src/librustc_codegen_llvm/back/link.rs
+++ b/src/librustc_codegen_llvm/back/link.rs
@@ -47,7 +47,8 @@ use std::str;
 use syntax::attr;
 
 pub use rustc_codegen_utils::link::{find_crate_name, filename_for_input, default_output_for_target,
-                                  invalid_output_for_target, out_filename, check_file_is_writeable};
+                                  invalid_output_for_target, out_filename, check_file_is_writeable,
+                                  filename_for_metadata};
 
 // 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
@@ -218,15 +219,6 @@ fn preserve_objects_for_their_debuginfo(sess: &Session) -> bool {
     false
 }
 
-fn filename_for_metadata(sess: &Session, crate_name: &str, outputs: &OutputFilenames) -> PathBuf {
-    let out_filename = outputs.single_output_file.clone()
-        .unwrap_or(outputs
-            .out_directory
-            .join(&format!("lib{}{}.rmeta", crate_name, sess.opts.cg.extra_filename)));
-    check_file_is_writeable(&out_filename, sess);
-    out_filename
-}
-
 pub(crate) fn each_linked_rlib(sess: &Session,
                                info: &CrateInfo,
                                f: &mut dyn FnMut(CrateNum, &Path)) -> Result<(), String> {
diff --git a/src/librustc_codegen_utils/link.rs b/src/librustc_codegen_utils/link.rs
index 75f1d614ae7..3d47f91a623 100644
--- a/src/librustc_codegen_utils/link.rs
+++ b/src/librustc_codegen_utils/link.rs
@@ -97,6 +97,19 @@ pub fn find_crate_name(sess: Option<&Session>,
     "rust_out".to_string()
 }
 
+pub fn filename_for_metadata(sess: &Session,
+                             crate_name: &str,
+                             outputs: &OutputFilenames) -> PathBuf {
+    let libname = format!("{}{}", crate_name, sess.opts.cg.extra_filename);
+
+    let out_filename = outputs.single_output_file.clone()
+        .unwrap_or(outputs.out_directory.join(&format!("lib{}.rmeta", libname)));
+
+    check_file_is_writeable(&out_filename, sess);
+
+    out_filename
+}
+
 pub fn filename_for_input(sess: &Session,
                           crate_type: config::CrateType,
                           crate_name: &str,
diff --git a/src/librustc_driver/lib.rs b/src/librustc_driver/lib.rs
index f8ca154d168..27176a821b4 100644
--- a/src/librustc_driver/lib.rs
+++ b/src/librustc_driver/lib.rs
@@ -980,6 +980,7 @@ pub fn enable_save_analysis(control: &mut CompileController) {
                                 state.expanded_crate.unwrap(),
                                 state.analysis.unwrap(),
                                 state.crate_name.unwrap(),
+                                state.input,
                                 None,
                                 DumpHandler::new(state.out_dir,
                                                  state.crate_name.unwrap()))
diff --git a/src/librustc_save_analysis/Cargo.toml b/src/librustc_save_analysis/Cargo.toml
index b6dd9ec8d3f..e47f89c64ff 100644
--- a/src/librustc_save_analysis/Cargo.toml
+++ b/src/librustc_save_analysis/Cargo.toml
@@ -12,6 +12,7 @@ crate-type = ["dylib"]
 log = "0.4"
 rustc = { path = "../librustc" }
 rustc_data_structures = { path = "../librustc_data_structures" }
+rustc_codegen_utils = { path = "../librustc_codegen_utils" }
 rustc_target = { path = "../librustc_target" }
 rustc_typeck = { path = "../librustc_typeck" }
 syntax = { path = "../libsyntax" }
diff --git a/src/librustc_save_analysis/dump_visitor.rs b/src/librustc_save_analysis/dump_visitor.rs
index d719d257f35..ab8f4686729 100644
--- a/src/librustc_save_analysis/dump_visitor.rs
+++ b/src/librustc_save_analysis/dump_visitor.rs
@@ -25,10 +25,12 @@
 
 use rustc::hir::def::Def as HirDef;
 use rustc::hir::def_id::DefId;
+use rustc::session::config::Input;
 use rustc::ty::{self, TyCtxt};
 use rustc_data_structures::fx::FxHashSet;
 
 use std::path::Path;
+use std::env;
 
 use syntax::ast::{self, Attribute, NodeId, PatKind, CRATE_NODE_ID};
 use syntax::parse::token;
@@ -49,8 +51,8 @@ use json_dumper::{Access, DumpOutput, JsonDumper};
 use span_utils::SpanUtils;
 use sig;
 
-use rls_data::{CratePreludeData, Def, DefKind, GlobalCrateId, Import, ImportKind, Ref, RefKind,
-               Relation, RelationKind, SpanData};
+use rls_data::{CompilationOptions, CratePreludeData, Def, DefKind, GlobalCrateId, Import,
+               ImportKind, Ref, RefKind, Relation, RelationKind, SpanData};
 
 macro_rules! down_cast_data {
     ($id:ident, $kind:ident, $sp:expr) => {
@@ -169,6 +171,54 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
         self.dumper.crate_prelude(data);
     }
 
+    pub fn dump_compilation_options(&mut self, input: &Input, crate_name: &str) {
+        // Apply possible `remap-path-prefix` remapping to the input source file
+        // (and don't include remapping args anymore)
+        let (program, arguments) = {
+            let remap_arg_indices = {
+                let mut indices = FxHashSet();
+                // Args are guaranteed to be valid UTF-8 (checked early)
+                for (i, e) in env::args().enumerate() {
+                    if e.starts_with("--remap-path-prefix=") {
+                        indices.insert(i);
+                    } else if e == "--remap-path-prefix" {
+                        indices.insert(i);
+                        indices.insert(i + 1);
+                    }
+                }
+                indices
+            };
+
+            let mut args = env::args()
+                .enumerate()
+                .filter(|(i, _)| !remap_arg_indices.contains(i))
+                .map(|(_, arg)| {
+                    match input {
+                        Input::File(ref path) if path == Path::new(&arg) => {
+                            let mapped = &self.tcx.sess.local_crate_source_file;
+                            mapped
+                                .as_ref()
+                                .unwrap()
+                                .to_string_lossy()
+                                .into()
+                        },
+                        _ => arg,
+                    }
+                });
+
+            (args.next().unwrap(), args.collect())
+        };
+
+        let data = CompilationOptions {
+            directory: self.tcx.sess.working_dir.0.clone(),
+            program,
+            arguments,
+            output: self.save_ctxt.compilation_output(crate_name),
+        };
+
+        self.dumper.compilation_opts(data);
+    }
+
     // Return all non-empty prefixes of a path.
     // For each prefix, we return the span for the last segment in the prefix and
     // a str representation of the entire prefix.
diff --git a/src/librustc_save_analysis/json_dumper.rs b/src/librustc_save_analysis/json_dumper.rs
index d2e52f98238..e14ac73ee10 100644
--- a/src/librustc_save_analysis/json_dumper.rs
+++ b/src/librustc_save_analysis/json_dumper.rs
@@ -12,9 +12,9 @@ use std::io::Write;
 
 use rustc_serialize::json::as_json;
 
-use rls_data::{self, Analysis, CratePreludeData, Def, DefKind, Import, MacroRef, Ref, RefKind,
-               Relation, Impl};
 use rls_data::config::Config;
+use rls_data::{self, Analysis, CompilationOptions, CratePreludeData, Def, DefKind, Impl, Import,
+               MacroRef, Ref, RefKind, Relation};
 use rls_span::{Column, Row};
 
 #[derive(Debug)]
@@ -89,6 +89,10 @@ impl<'b, O: DumpOutput + 'b> JsonDumper<O> {
         self.result.prelude = Some(data)
     }
 
+    pub fn compilation_opts(&mut self, data: CompilationOptions) {
+        self.result.compilation = Some(data);
+    }
+
     pub fn macro_use(&mut self, data: MacroRef) {
         if self.config.pub_only || self.config.reachable_only {
             return;
diff --git a/src/librustc_save_analysis/lib.rs b/src/librustc_save_analysis/lib.rs
index c9bae297031..f6045c7b2d2 100644
--- a/src/librustc_save_analysis/lib.rs
+++ b/src/librustc_save_analysis/lib.rs
@@ -23,6 +23,7 @@ extern crate rustc;
 #[macro_use]
 extern crate log;
 extern crate rustc_data_structures;
+extern crate rustc_codegen_utils;
 extern crate rustc_serialize;
 extern crate rustc_target;
 extern crate rustc_typeck;
@@ -45,9 +46,10 @@ use rustc::hir::def::Def as HirDef;
 use rustc::hir::Node;
 use rustc::hir::def_id::{DefId, LOCAL_CRATE};
 use rustc::middle::cstore::ExternCrate;
-use rustc::session::config::CrateType;
+use rustc::session::config::{CrateType, Input, OutputType};
 use rustc::ty::{self, TyCtxt};
 use rustc_typeck::hir_ty_to_ty;
+use rustc_codegen_utils::link::{filename_for_metadata, out_filename};
 
 use std::cell::Cell;
 use std::default::Default;
@@ -110,6 +112,24 @@ impl<'l, 'tcx: 'l> SaveContext<'l, 'tcx> {
         }
     }
 
+    // Returns path to the compilation output (e.g. libfoo-12345678.rmeta)
+    pub fn compilation_output(&self, crate_name: &str) -> PathBuf {
+        let sess = &self.tcx.sess;
+        // Save-analysis is emitted per whole session, not per each crate type
+        let crate_type = sess.crate_types.borrow()[0];
+        let outputs = &*self.tcx.output_filenames(LOCAL_CRATE);
+
+        if outputs.outputs.contains_key(&OutputType::Metadata) {
+            filename_for_metadata(sess, crate_name, outputs)
+        } else if outputs.outputs.should_codegen() {
+            out_filename(sess, crate_type, outputs, crate_name)
+        } else {
+            // Otherwise it's only a DepInfo, in which case we return early and
+            // not even reach the analysis stage.
+            unreachable!()
+        }
+    }
+
     // List external crates used by the current crate.
     pub fn get_external_crates(&self) -> Vec<ExternalCrateData> {
         let mut result = Vec::with_capacity(self.tcx.crates().len());
@@ -126,7 +146,7 @@ impl<'l, 'tcx: 'l> SaveContext<'l, 'tcx> {
             result.push(ExternalCrateData {
                 // FIXME: change file_name field to PathBuf in rls-data
                 // https://github.com/nrc/rls-data/issues/7
-                file_name: self.span_utils.make_path_string(&lo_loc.file.name),
+                file_name: self.span_utils.make_filename_string(&lo_loc.file),
                 num: n.as_u32(),
                 id: GlobalCrateId {
                     name: self.tcx.crate_name(n).to_string(),
@@ -1015,6 +1035,7 @@ pub trait SaveHandler {
         save_ctxt: SaveContext<'l, 'tcx>,
         krate: &ast::Crate,
         cratename: &str,
+        input: &'l Input,
     );
 }
 
@@ -1080,12 +1101,14 @@ impl<'a> SaveHandler for DumpHandler<'a> {
         save_ctxt: SaveContext<'l, 'tcx>,
         krate: &ast::Crate,
         cratename: &str,
+        input: &'l Input,
     ) {
         let output = &mut self.output_file(&save_ctxt);
         let mut dumper = JsonDumper::new(output, save_ctxt.config.clone());
         let mut visitor = DumpVisitor::new(save_ctxt, &mut dumper);
 
         visitor.dump_crate_info(cratename, krate);
+        visitor.dump_compilation_options(input, cratename);
         visit::walk_crate(&mut visitor, krate);
     }
 }
@@ -1101,6 +1124,7 @@ impl<'b> SaveHandler for CallbackHandler<'b> {
         save_ctxt: SaveContext<'l, 'tcx>,
         krate: &ast::Crate,
         cratename: &str,
+        input: &'l Input,
     ) {
         // We're using the JsonDumper here because it has the format of the
         // save-analysis results that we will pass to the callback. IOW, we are
@@ -1111,6 +1135,7 @@ impl<'b> SaveHandler for CallbackHandler<'b> {
         let mut visitor = DumpVisitor::new(save_ctxt, &mut dumper);
 
         visitor.dump_crate_info(cratename, krate);
+        visitor.dump_compilation_options(input, cratename);
         visit::walk_crate(&mut visitor, krate);
     }
 }
@@ -1120,6 +1145,7 @@ pub fn process_crate<'l, 'tcx, H: SaveHandler>(
     krate: &ast::Crate,
     analysis: &'l ty::CrateAnalysis,
     cratename: &str,
+    input: &'l Input,
     config: Option<Config>,
     mut handler: H,
 ) {
@@ -1137,7 +1163,7 @@ pub fn process_crate<'l, 'tcx, H: SaveHandler>(
             impl_counter: Cell::new(0),
         };
 
-        handler.save(save_ctxt, krate, cratename)
+        handler.save(save_ctxt, krate, cratename, input)
     })
 }
 
diff --git a/src/librustc_save_analysis/span_utils.rs b/src/librustc_save_analysis/span_utils.rs
index 2550a312c5d..47677a75171 100644
--- a/src/librustc_save_analysis/span_utils.rs
+++ b/src/librustc_save_analysis/span_utils.rs
@@ -35,14 +35,24 @@ impl<'a> SpanUtils<'a> {
         }
     }
 
-    pub fn make_path_string(&self, path: &FileName) -> String {
-        match *path {
-            FileName::Real(ref path) if !path.is_absolute() =>
-                self.sess.working_dir.0
-                    .join(&path)
-                    .display()
-                    .to_string(),
-            _ => path.to_string(),
+    pub fn make_filename_string(&self, file: &SourceFile) -> String {
+        match &file.name {
+            FileName::Real(path) if !file.name_was_remapped => {
+                if path.is_absolute() {
+                    self.sess.source_map().path_mapping()
+                        .map_prefix(path.clone()).0
+                        .display()
+                        .to_string()
+                } else {
+                    self.sess.working_dir.0
+                        .join(&path)
+                        .display()
+                        .to_string()
+                }
+            },
+            // If the file name is already remapped, we assume the user
+            // configured it the way they wanted to, so use that directly
+            filename => filename.to_string()
         }
     }