musl: don't use the included startfiles with -crt-static

This fixes rust-lang#36710 with -crt-static.

src/librustc_target/spec/linux_musl_base.rs

@@ -15,7 +15,8 @@ pub fn opts() -> TargetOptions {
 
     // Make sure that the linker/gcc really don't pull in anything, including
     // default objects, libs, etc.
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-nostdlib".to_string());
+    base.pre_link_args_crt.insert(LinkerFlavor::Gcc, Vec::new());
+    base.pre_link_args_crt.get_mut(&LinkerFlavor::Gcc).unwrap().push("-nostdlib".to_string());
 
     // At least when this was tested, the linker would not add the
     // `GNU_EH_FRAME` program header to executables generated, which is required
@@ -55,9 +56,9 @@ pub fn opts() -> TargetOptions {
     //
     // Each target directory for musl has these object files included in it so
     // they'll be included from there.
-    base.pre_link_objects_exe.push("crt1.o".to_string());
-    base.pre_link_objects_exe.push("crti.o".to_string());
-    base.post_link_objects.push("crtn.o".to_string());
+    base.pre_link_objects_exe_crt.push("crt1.o".to_string());
+    base.pre_link_objects_exe_crt.push("crti.o".to_string());
+    base.post_link_objects_crt.push("crtn.o".to_string());
 
     // These targets statically link libc by default
     base.crt_static_default = true;

src/librustc_target/spec/mod.rs

@@ -420,20 +420,22 @@ pub struct TargetOptions {
     /// Linker to invoke
     pub linker: Option<String>,
 
-    /// Linker arguments that are unconditionally passed *before* any
-    /// user-defined libraries.
-    pub pre_link_args: LinkArgs,
+    /// 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
     /// Objects to link before all others, always found within the
     /// sysroot folder.
-    pub pre_link_objects_exe: Vec<String>, // ... when linking an executable
+    pub pre_link_objects_exe: Vec<String>, // ... when linking an executable, unconditionally
+    pub pre_link_objects_exe_crt: Vec<String>, // ... when linking an executable with a bundled crt
     pub pre_link_objects_dll: Vec<String>, // ... when linking a dylib
     /// Linker arguments that are unconditionally passed after any
     /// user-defined but before post_link_objects.  Standard platform
     /// libraries that should be always be linked to, usually go here.
     pub late_link_args: LinkArgs,
     /// Objects to link after all others, always found within the
     /// sysroot folder.
-    pub post_link_objects: Vec<String>,
+    pub post_link_objects: Vec<String>, // ... unconditionally
+    pub post_link_objects_crt: Vec<String>, // ... when linking with a bundled crt
     /// Linker arguments that are unconditionally passed *after* any
     /// user-defined libraries.
     pub post_link_args: LinkArgs,
@@ -633,6 +635,7 @@ impl Default for TargetOptions {
             is_builtin: false,
             linker: option_env!("CFG_DEFAULT_LINKER").map(|s| s.to_string()),
             pre_link_args: LinkArgs::new(),
+            pre_link_args_crt: LinkArgs::new(),
             post_link_args: LinkArgs::new(),
             asm_args: Vec::new(),
             cpu: "generic".to_string(),
@@ -666,8 +669,10 @@ impl Default for TargetOptions {
             position_independent_executables: false,
             relro_level: RelroLevel::None,
             pre_link_objects_exe: Vec::new(),
+            pre_link_objects_exe_crt: Vec::new(),
             pre_link_objects_dll: Vec::new(),
             post_link_objects: Vec::new(),
+            post_link_objects_crt: Vec::new(),
             late_link_args: LinkArgs::new(),
             link_env: Vec::new(),
             archive_format: "gnu".to_string(),
@@ -886,10 +891,13 @@ impl Target {
         key!(is_builtin, bool);
         key!(linker, optional);
         key!(pre_link_args, link_args);
+        key!(pre_link_args_crt, link_args);
         key!(pre_link_objects_exe, list);
+        key!(pre_link_objects_exe_crt, list);
         key!(pre_link_objects_dll, list);
         key!(late_link_args, link_args);
         key!(post_link_objects, list);
+        key!(post_link_objects_crt, list);
         key!(post_link_args, link_args);
         key!(link_env, env);
         key!(asm_args, list);
@@ -1091,10 +1099,13 @@ impl ToJson for Target {
         target_option_val!(is_builtin);
         target_option_val!(linker);
         target_option_val!(link_args - pre_link_args);
+        target_option_val!(link_args - pre_link_args_crt);
         target_option_val!(pre_link_objects_exe);
+        target_option_val!(pre_link_objects_exe_crt);
         target_option_val!(pre_link_objects_dll);
         target_option_val!(link_args - late_link_args);
         target_option_val!(post_link_objects);
+        target_option_val!(post_link_objects_crt);
         target_option_val!(link_args - post_link_args);
         target_option_val!(env - link_env);
         target_option_val!(asm_args);

src/librustc_trans/back/link.rs

@@ -621,6 +621,11 @@ fn link_natively(sess: &Session,
     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() {
+            cmd.args(args);
+        }
+    }
     if let Some(ref args) = sess.opts.debugging_opts.pre_link_args {
         cmd.args(args);
     }
@@ -635,6 +640,12 @@ fn link_natively(sess: &Session,
         cmd.arg(root.join(obj));
     }
 
+    if crate_type == config::CrateTypeExecutable && sess.crt_static() {
+        for obj in &sess.target.target.options.pre_link_objects_exe_crt {
+            cmd.arg(root.join(obj));
+        }
+    }
+
     if sess.target.target.options.is_like_emscripten {
         cmd.arg("-s");
         cmd.arg(if sess.panic_strategy() == PanicStrategy::Abort {
@@ -656,6 +667,11 @@ fn link_natively(sess: &Session,
     for obj in &sess.target.target.options.post_link_objects {
         cmd.arg(root.join(obj));
     }
+    if sess.crt_static() {
+        for obj in &sess.target.target.options.post_link_objects_crt {
+            cmd.arg(root.join(obj));
+        }
+    }
     if let Some(args) = sess.target.target.options.post_link_args.get(&flavor) {
         cmd.args(args);
     }