Add rustc SHA to released DWARF debuginfo

This commit updates the debuginfo that is encoded in all of our released
artifacts by default. Currently it has paths like `/checkout/src/...` but these
are a little inconsistent and have changed over time. This commit instead
attempts to actually define the file paths in our debuginfo to be consistent
between releases.

All debuginfo paths are now intended to be `/rustc/$sha` where `$sha` is the git
sha of the released compiler. Sub-paths are all paths into the git repo at that
`$sha`.

Author: alexcrichton

.travis.yml

@@ -40,7 +40,7 @@ matrix:
         CI_JOB_NAME=dist-x86_64-apple-alt
       os: osx
       osx_image: xcode9.3-moar
-      if: branch = auto
+      if: branch = auto OR branch = try
 
     # macOS builders. These are placed near the beginning because they are very
     # slow to run.

config.toml.example

@@ -373,6 +373,10 @@
 # Whether to verify generated LLVM IR
 #verify-llvm-ir = false
 
+# Map all debuginfo paths for libstd and crates to `/rust/$sha/$crate/...`,
+# generally only set for releases
+#remap-debuginfo = false
+
 # =============================================================================
 # Options for specific targets
 #

src/bootstrap/bin/rustc.rs

@@ -263,6 +263,10 @@ fn main() {
         if env::var_os("RUSTC_FORCE_UNSTABLE").is_some() {
             cmd.arg("-Z").arg("force-unstable-if-unmarked");
         }
+
+        if let Ok(map) = env::var("RUSTC_DEBUGINFO_MAP") {
+            cmd.arg("--remap-path-prefix").arg(&map);
+        }
     } else {
         // Override linker if necessary.
         if let Ok(host_linker) = env::var("RUSTC_HOST_LINKER") {

src/bootstrap/builder.rs

@@ -876,6 +876,10 @@ impl<'a> Builder<'a> {
             cargo.env("RUSTC_HOST_CRT_STATIC", x.to_string());
         }
 
+        if let Some(map) = self.build.debuginfo_map() {
+            cargo.env("RUSTC_DEBUGINFO_MAP", map);
+        }
+
         // Enable usage of unstable features
         cargo.env("RUSTC_BOOTSTRAP", "1");
         self.add_rust_test_threads(&mut cargo);

src/bootstrap/config.rs

@@ -108,6 +108,7 @@ pub struct Config {
     pub rust_codegen_backends: Vec<Interned<String>>,
     pub rust_codegen_backends_dir: String,
     pub rust_verify_llvm_ir: bool,
+    pub rust_remap_debuginfo: bool,
 
     pub build: Interned<String>,
     pub hosts: Vec<Interned<String>>,
@@ -319,6 +320,7 @@ struct Rust {
     deny_warnings: Option<bool>,
     backtrace_on_ice: Option<bool>,
     verify_llvm_ir: Option<bool>,
+    remap_debuginfo: Option<bool>,
 }
 
 /// TOML representation of how each build target is configured.
@@ -554,6 +556,7 @@ impl Config {
             set(&mut config.deny_warnings, rust.deny_warnings.or(flags.warnings));
             set(&mut config.backtrace_on_ice, rust.backtrace_on_ice);
             set(&mut config.rust_verify_llvm_ir, rust.verify_llvm_ir);
+            set(&mut config.rust_remap_debuginfo, rust.remap_debuginfo);
 
             if let Some(ref backends) = rust.codegen_backends {
                 config.rust_codegen_backends = backends.iter()

src/bootstrap/lib.rs

@@ -737,6 +737,15 @@ impl Build {
         self.config.jobs.unwrap_or_else(|| num_cpus::get() as u32)
     }
 
+    fn debuginfo_map(&self) -> Option<String> {
+        if !self.config.rust_remap_debuginfo {
+            return None
+        }
+
+        let sha = self.rust_sha().expect("failed to find rust sha");
+        Some(format!("{}=/rustc/{}", self.src.display(), sha))
+    }
+
     /// Returns the path to the C compiler for the target specified.
     fn cc(&self, target: Interned<String>) -> &Path {
         self.cc[&target].path()
@@ -766,6 +775,12 @@ impl Build {
         if &*target == "i686-pc-windows-gnu" {
             base.push("-fno-omit-frame-pointer".into());
         }
+
+        if self.cc(target).ends_with("clang") {
+            if let Some(map) = self.debuginfo_map() {
+                base.push(format!("-fdebug-prefix-map={}", map).into());
+            }
+        }
         base
     }
 

src/ci/run.sh

@@ -40,6 +40,7 @@ RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --enable-sccache"
 RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --disable-manage-submodules"
 RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --enable-locked-deps"
 RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --enable-cargo-openssl-static"
+RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --set rust.remap-debuginfo"
 
 if [ "$DIST_SRC" = "" ]; then
   RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --disable-dist-src"

src/libstd/build.rs

@@ -97,6 +97,10 @@ fn build_libbacktrace(target: &str) -> Result<(), ()> {
         .file("../libbacktrace/sort.c")
         .file("../libbacktrace/state.c");
 
+    let any_debug = env::var("RUSTC_DEBUGINFO").unwrap_or(String::new()) == "true" ||
+        env::var("RUSTC_DEBUGINFO_LINES").unwrap_or(String::new()) == "true";
+    build.debug(any_debug);
+
     if target.contains("darwin") {
         build.file("../libbacktrace/macho.c");
     } else if target.contains("windows") {