Rollup merge of rust-lang#72782 - petrochenkov:crtargs, r=varkor

rustc_target: Remove `pre_link_args_crt`

To regain some more control over the definition of `+crt-static` (rust-lang#71586).

After rust-lang#71769 this target option wasn't used anywhere except for VxWorks, and I suspect that for VxWorks its use may be redundant as well.

Author: Dylan-DPC

src/librustc_codegen_ssa/back/link.rs

@@ -1253,20 +1253,10 @@ fn add_post_link_objects(
 
 /// Add arbitrary "pre-link" args defined by the target spec or from command line.
 /// FIXME: Determine where exactly these args need to be inserted.
-fn add_pre_link_args(
-    cmd: &mut dyn Linker,
-    sess: &Session,
-    flavor: LinkerFlavor,
-    crate_type: CrateType,
-) {
+fn add_pre_link_args(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor) {
     if let Some(args) = sess.target.target.options.pre_link_args.get(&flavor) {
         cmd.args(args);
     }
-    if let Some(args) = sess.target.target.options.pre_link_args_crt.get(&flavor) {
-        if sess.crt_static(Some(crate_type)) {
-            cmd.args(args);
-        }
-    }
     cmd.args(&sess.opts.debugging_opts.pre_link_args);
 }
 
@@ -1502,7 +1492,7 @@ fn linker_with_args<'a, B: ArchiveBuilder<'a>>(
     let crt_objects_fallback = crt_objects_fallback(sess, crate_type);
 
     // NO-OPT-OUT, OBJECT-FILES-MAYBE, CUSTOMIZATION-POINT
-    add_pre_link_args(cmd, sess, flavor, crate_type);
+    add_pre_link_args(cmd, sess, flavor);
 
     // NO-OPT-OUT
     add_link_script(cmd, sess, tmpdir, crate_type);

src/librustc_codegen_ssa/back/linker.rs

@@ -315,6 +315,21 @@ impl<'a> Linker for GccLinker<'a> {
                 self.build_dylib(out_filename);
             }
         }
+        // VxWorks compiler driver introduced `--static-crt` flag specifically for rustc,
+        // it switches linking for libc and similar system libraries to static without using
+        // any `#[link]` attributes in the `libc` crate, see #72782 for details.
+        // FIXME: Switch to using `#[link]` attributes in the `libc` crate
+        // similarly to other targets.
+        if self.sess.target.target.target_os == "vxworks"
+            && matches!(
+                output_kind,
+                LinkOutputKind::StaticNoPicExe
+                    | LinkOutputKind::StaticPicExe
+                    | LinkOutputKind::StaticDylib
+            )
+        {
+            self.cmd.arg("--static-crt");
+        }
     }
 
     fn link_dylib(&mut self, lib: Symbol) {

src/librustc_target/spec/mod.rs

@@ -733,8 +733,7 @@ pub struct TargetOptions {
     pub lld_flavor: LldFlavor,
 
     /// Linker arguments that are passed *before* any user-defined libraries.
-    pub pre_link_args: LinkArgs, // ... unconditionally
-    pub pre_link_args_crt: LinkArgs, // ... when linking with a bundled crt
+    pub pre_link_args: LinkArgs,
     /// Objects to link before and after all other object code.
     pub pre_link_objects: CrtObjects,
     pub post_link_objects: CrtObjects,
@@ -997,7 +996,6 @@ impl Default for TargetOptions {
             linker: option_env!("CFG_DEFAULT_LINKER").map(|s| s.to_string()),
             lld_flavor: LldFlavor::Ld,
             pre_link_args: LinkArgs::new(),
-            pre_link_args_crt: LinkArgs::new(),
             post_link_args: LinkArgs::new(),
             link_script: None,
             asm_args: Vec::new(),
@@ -1397,7 +1395,6 @@ impl Target {
         key!(post_link_objects_fallback, link_objects);
         key!(crt_objects_fallback, crt_objects_fallback)?;
         key!(pre_link_args, link_args);
-        key!(pre_link_args_crt, link_args);
         key!(late_link_args, link_args);
         key!(late_link_args_dynamic, link_args);
         key!(late_link_args_static, link_args);
@@ -1629,7 +1626,6 @@ impl ToJson for Target {
         target_option_val!(post_link_objects_fallback);
         target_option_val!(crt_objects_fallback);
         target_option_val!(link_args - pre_link_args);
-        target_option_val!(link_args - pre_link_args_crt);
         target_option_val!(link_args - late_link_args);
         target_option_val!(link_args - late_link_args_dynamic);
         target_option_val!(link_args - late_link_args_static);

src/librustc_target/spec/tests/tests_impl.rs

@@ -25,7 +25,6 @@ impl Target {
         );
         for args in &[
             &self.options.pre_link_args,
-            &self.options.pre_link_args_crt,
             &self.options.late_link_args,
             &self.options.late_link_args_dynamic,
             &self.options.late_link_args_static,

src/librustc_target/spec/vxworks_base.rs

@@ -1,8 +1,6 @@
 use crate::spec::{LinkArgs, LinkerFlavor, TargetOptions};
 
 pub fn opts() -> TargetOptions {
-    let mut args_crt = LinkArgs::new();
-    args_crt.insert(LinkerFlavor::Gcc, vec!["--static-crt".to_string()]);
     let mut args = LinkArgs::new();
     args.insert(
         LinkerFlavor::Gcc,
@@ -29,7 +27,6 @@ pub fn opts() -> TargetOptions {
         pre_link_args: args,
         position_independent_executables: false,
         has_elf_tls: true,
-        pre_link_args_crt: args_crt,
         crt_static_default: true,
         crt_static_respected: true,
         crt_static_allows_dylibs: true,