Emit warning while outputs is not exe and prints linkage info

Signed-off-by: xizheyin <[email protected]>

Author: xizheyin

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -68,6 +68,23 @@ pub fn ensure_removed(dcx: DiagCtxtHandle<'_>, path: &Path) {
     }
 }
 
+fn check_link_info_print_request(sess: &Session, crate_type: CrateType) {
+    let print_native_static_libs =
+        sess.opts.prints.iter().any(|p| p.kind == PrintKind::NativeStaticLibs);
+    if print_native_static_libs {
+        if crate_type != CrateType::Staticlib {
+            sess.dcx()
+                .warn(format!("cannot output linkage information without staticlib crate-type"));
+            sess.dcx()
+                .note(format!("consider `--crate-type staticlib` to print linkage information"));
+        } else if !sess.opts.output_types.should_link() {
+            sess.dcx().warn(format!(
+                    "skipping link step due to conflict: cannot output linkage information without emitting link"
+                ));
+        }
+    }
+}
+
 /// Performs the linkage portion of the compilation phase. This will generate all
 /// of the requested outputs for this compilation session.
 pub fn link_binary(
@@ -178,6 +195,8 @@ pub fn link_binary(
                 tempfiles_for_stdout_output.push(out_filename);
             }
         }
+
+        check_link_info_print_request(sess, crate_type);
     }
 
     // Remove the temporary object file and metadata if we aren't saving temps.

tests/ui/print-request/emit-warning-print-link-info-without-staticlib.rs

@@ -0,0 +1,5 @@
+//@ compile-flags: --print native-static-libs
+//@ check-pass
+//~? WARN cannot output linkage information without staticlib crate-type
+
+fn main() {}

tests/ui/print-request/emit-warning-print-link-info-without-staticlib.stderr

@@ -0,0 +1,6 @@
+warning: cannot output linkage information without staticlib crate-type
+
+note: consider `--crate-type staticlib` to print linkage information
+
+warning: 1 warning emitted
+

tests/ui/print-request/emit-warning-while-exe-and-print-link-info.rs

@@ -0,0 +1,3 @@
+//@ compile-flags: --print native-static-libs --crate-type staticlib  --emit metadata
+//@ check-pass
+//~? WARN skipping link step due to conflict: cannot output linkage information without emitting link

tests/ui/print-request/emit-warning-while-exe-and-print-link-info.stderr

@@ -0,0 +1,4 @@
+warning: skipping link step due to conflict: cannot output linkage information without emitting link
+
+warning: 1 warning emitted
+

tests/ui/print-request/stability.rs

@@ -110,3 +110,4 @@ fn main() {}
 //[check_cfg]~? ERROR the `-Z unstable-options` flag must also be passed to enable the `check-cfg` print option
 //[supported_crate_types]~? ERROR the `-Z unstable-options` flag must also be passed to enable the `supported-crate-types` print option
 //[target_spec_json]~? ERROR the `-Z unstable-options` flag must also be passed to enable the `target-spec-json` print option
+//[native_static_libs]~? WARNING cannot output linkage information without staticlib crate-type