Stabilize -Z strip as -C strip

Leave -Z strip available temporarily as an alias, to avoid breaking
cargo until cargo transitions to using -C strip. (If the user passes
both, the -C version wins.)

Author: joshtriplett

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -1034,15 +1034,25 @@ fn link_natively<'a, B: ArchiveBuilder<'a>>(
         SplitDebuginfo::Packed => link_dwarf_object(sess, &out_filename),
     }
 
+    let strip = strip_value(sess);
+
     if sess.target.is_like_osx {
-        match sess.opts.debugging_opts.strip {
+        match strip {
             Strip::Debuginfo => strip_symbols_in_osx(sess, &out_filename, Some("-S")),
             Strip::Symbols => strip_symbols_in_osx(sess, &out_filename, None),
             Strip::None => {}
         }
     }
 }
 
+// Temporarily support both -Z strip and -C strip
+fn strip_value(sess: &Session) -> Strip {
+    match (sess.opts.debugging_opts.strip, sess.opts.cg.strip) {
+        (s, Strip::None) => s,
+        (_, s) => s,
+    }
+}
+
 fn strip_symbols_in_osx<'a>(sess: &'a Session, out_filename: &Path, option: Option<&str>) {
     let mut cmd = Command::new("strip");
     if let Some(option) = option {
@@ -2014,7 +2024,7 @@ fn add_order_independent_options(
     cmd.optimize();
 
     // Pass debuginfo and strip flags down to the linker.
-    cmd.debuginfo(sess.opts.debugging_opts.strip);
+    cmd.debuginfo(strip_value(sess));
 
     // We want to prevent the compiler from accidentally leaking in any system libraries,
     // so by default we tell linkers not to link to any default libraries.

compiler/rustc_interface/src/tests.rs

@@ -551,6 +551,7 @@ fn test_codegen_options_tracking_hash() {
     untracked!(remark, Passes::Some(vec![String::from("pass1"), String::from("pass2")]));
     untracked!(rpath, true);
     untracked!(save_temps, true);
+    untracked!(strip, Strip::Debuginfo);
 
     macro_rules! tracked {
         ($name: ident, $non_default_value: expr) => {
@@ -684,7 +685,6 @@ fn test_debugging_options_tracking_hash() {
     untracked!(self_profile_events, Some(vec![String::new()]));
     untracked!(span_debug, true);
     untracked!(span_free_formats, true);
-    untracked!(strip, Strip::Debuginfo);
     untracked!(temps_dir, Some(String::from("abc")));
     untracked!(terminal_width, Some(80));
     untracked!(threads, 99);

compiler/rustc_session/src/config.rs

@@ -37,7 +37,7 @@ use std::iter::{self, FromIterator};
 use std::path::{Path, PathBuf};
 use std::str::{self, FromStr};
 
-/// The different settings that the `-Z strip` flag can have.
+/// The different settings that the `-C strip` flag can have.
 #[derive(Clone, Copy, PartialEq, Hash, Debug)]
 pub enum Strip {
     /// Do not strip at all.

compiler/rustc_session/src/options.rs

@@ -1015,6 +1015,8 @@ options! {
         "use soft float ABI (*eabihf targets only) (default: no)"),
     split_debuginfo: Option<SplitDebuginfo> = (None, parse_split_debuginfo, [TRACKED],
         "how to handle split-debuginfo, a platform-specific option"),
+    strip: Strip = (Strip::None, parse_strip, [UNTRACKED],
+        "tell the linker which information to strip (`none` (default), `debuginfo` or `symbols`)"),
     target_cpu: Option<String> = (None, parse_opt_string, [TRACKED],
         "select target processor (`rustc --print target-cpus` for details)"),
     target_feature: String = (String::new(), parse_target_feature, [TRACKED],

src/doc/rustc/src/codegen-options/index.md

@@ -525,6 +525,22 @@ platforms. Possible values are:
 Note that `packed` and `unpacked` are gated behind `-Z unstable-options` on
 non-macOS platforms at this time.
 
+## strip
+
+The option `-C strip=val` controls stripping of debuginfo and similar auxiliary
+data from binaries during linking.
+
+Supported values for this option are:
+
+- `none` - debuginfo and symbols (if they exist) are copied to the produced
+  binary or separate files depending on the target (e.g. `.pdb` files in case
+  of MSVC).
+- `debuginfo` - debuginfo sections and debuginfo symbols from the symbol table
+  section are stripped at link time and are not copied to the produced binary
+  or separate files.
+- `symbols` - same as `debuginfo`, but the rest of the symbol table section is
+  stripped as well if the linker supports it.
+
 ## target-cpu
 
 This instructs `rustc` to generate code specifically for a particular processor.