@@ -303,13 +303,19 @@ pub(crate) trait Linker {
303303 crate_type : CrateType ,
304304 out_filename : & Path ,
305305 ) ;
306- fn link_dylib_by_name ( & mut self , _name : & str , _verbatim : bool , _as_needed : bool ) {
306+ fn link_dylib_by_name ( & mut self , _name : & str , _verbatim : bool , _as_needed : bool , _weak : bool ) {
307307 bug ! ( "dylib linked with unsupported linker" )
308308 }
309- fn link_dylib_by_path ( & mut self , _path : & Path , _as_needed : bool ) {
309+ fn link_dylib_by_path ( & mut self , _path : & Path , _as_needed : bool , _weak : bool ) {
310310 bug ! ( "dylib linked with unsupported linker" )
311311 }
312- fn link_framework_by_name ( & mut self , _name : & str , _verbatim : bool , _as_needed : bool ) {
312+ fn link_framework_by_name (
313+ & mut self ,
314+ _name : & str ,
315+ _verbatim : bool ,
316+ _as_needed : bool ,
317+ _weak : bool ,
318+ ) {
313319 bug ! ( "framework linked with unsupported linker" )
314320 }
315321 fn link_staticlib_by_name ( & mut self , name : & str , verbatim : bool , whole_archive : bool ) ;
@@ -569,7 +575,7 @@ impl<'a> Linker for GccLinker<'a> {
569575 }
570576 }
571577
572- fn link_dylib_by_name ( & mut self , name : & str , verbatim : bool , as_needed : bool ) {
578+ fn link_dylib_by_name ( & mut self , name : & str , verbatim : bool , as_needed : bool , weak : bool ) {
573579 if self . sess . target . os == "illumos" && name == "c" {
574580 // libc will be added via late_link_args on illumos so that it will
575581 // appear last in the library search order.
@@ -581,26 +587,39 @@ impl<'a> Linker for GccLinker<'a> {
581587 self . hint_dynamic ( ) ;
582588 self . with_as_needed ( as_needed, |this| {
583589 let colon = if verbatim && this. is_gnu { ":" } else { "" } ;
584- this. link_or_cc_arg ( format ! ( "-l{colon}{name}" ) ) ;
590+ if weak {
591+ this. link_or_cc_arg ( format ! ( "-weak-l{colon}{name}" ) ) ;
592+ } else {
593+ this. link_or_cc_arg ( format ! ( "-l{colon}{name}" ) ) ;
594+ }
585595 } ) ;
586596 }
587597
588- fn link_dylib_by_path ( & mut self , path : & Path , as_needed : bool ) {
598+ fn link_dylib_by_path ( & mut self , path : & Path , as_needed : bool , weak : bool ) {
589599 self . hint_dynamic ( ) ;
590600 self . with_as_needed ( as_needed, |this| {
591- this. link_or_cc_arg ( path) ;
601+ if weak {
602+ this. link_or_cc_arg ( "-weak_library" ) ;
603+ this. link_or_cc_arg ( path) ;
604+ } else {
605+ this. link_or_cc_arg ( path) ;
606+ }
592607 } )
593608 }
594609
595- fn link_framework_by_name ( & mut self , name : & str , _verbatim : bool , as_needed : bool ) {
610+ fn link_framework_by_name ( & mut self , name : & str , _verbatim : bool , as_needed : bool , weak : bool ) {
596611 self . hint_dynamic ( ) ;
597612 if !as_needed {
598613 // FIXME(81490): ld64 as of macOS 11 supports the -needed_framework
599614 // flag but we have no way to detect that here.
600615 // self.link_or_cc_arg("-needed_framework").link_or_cc_arg(name);
601616 self . sess . dcx ( ) . emit_warn ( errors:: Ld64UnimplementedModifier ) ;
602617 }
603- self . link_or_cc_args ( & [ "-framework" , name] ) ;
618+ if weak {
619+ self . link_or_cc_args ( & [ "-weak_framework" , name] ) ;
620+ } else {
621+ self . link_or_cc_args ( & [ "-framework" , name] ) ;
622+ }
604623 }
605624
606625 fn link_staticlib_by_name ( & mut self , name : & str , verbatim : bool , whole_archive : bool ) {
@@ -923,7 +942,7 @@ impl<'a> Linker for MsvcLinker<'a> {
923942 }
924943 }
925944
926- fn link_dylib_by_name ( & mut self , name : & str , verbatim : bool , _as_needed : bool ) {
945+ fn link_dylib_by_name ( & mut self , name : & str , verbatim : bool , _as_needed : bool , _weak : bool ) {
927946 // On MSVC-like targets rustc supports import libraries using alternative naming
928947 // scheme (`libfoo.a`) unsupported by linker, search for such libraries manually.
929948 if let Some ( path) = try_find_native_dynamic_library ( self . sess , name, verbatim) {
@@ -933,7 +952,7 @@ impl<'a> Linker for MsvcLinker<'a> {
933952 }
934953 }
935954
936- fn link_dylib_by_path ( & mut self , path : & Path , _as_needed : bool ) {
955+ fn link_dylib_by_path ( & mut self , path : & Path , _as_needed : bool , _weak : bool ) {
937956 // When producing a dll, MSVC linker may not emit an implib file if the dll doesn't export
938957 // any symbols, so we skip linking if the implib file is not present.
939958 let implib_path = path. with_extension ( "dll.lib" ) ;
@@ -1171,12 +1190,12 @@ impl<'a> Linker for EmLinker<'a> {
11711190 ) {
11721191 }
11731192
1174- fn link_dylib_by_name ( & mut self , name : & str , _verbatim : bool , _as_needed : bool ) {
1193+ fn link_dylib_by_name ( & mut self , name : & str , _verbatim : bool , _as_needed : bool , _weak : bool ) {
11751194 // Emscripten always links statically
11761195 self . link_or_cc_args ( & [ "-l" , name] ) ;
11771196 }
11781197
1179- fn link_dylib_by_path ( & mut self , path : & Path , _as_needed : bool ) {
1198+ fn link_dylib_by_path ( & mut self , path : & Path , _as_needed : bool , _weak : bool ) {
11801199 self . link_or_cc_arg ( path) ;
11811200 }
11821201
@@ -1338,11 +1357,11 @@ impl<'a> Linker for WasmLd<'a> {
13381357 }
13391358 }
13401359
1341- fn link_dylib_by_name ( & mut self , name : & str , _verbatim : bool , _as_needed : bool ) {
1360+ fn link_dylib_by_name ( & mut self , name : & str , _verbatim : bool , _as_needed : bool , _weak : bool ) {
13421361 self . link_or_cc_args ( & [ "-l" , name] ) ;
13431362 }
13441363
1345- fn link_dylib_by_path ( & mut self , path : & Path , _as_needed : bool ) {
1364+ fn link_dylib_by_path ( & mut self , path : & Path , _as_needed : bool , _weak : bool ) {
13461365 self . link_or_cc_arg ( path) ;
13471366 }
13481367
@@ -1643,12 +1662,12 @@ impl<'a> Linker for AixLinker<'a> {
16431662 }
16441663 }
16451664
1646- fn link_dylib_by_name ( & mut self , name : & str , _verbatim : bool , _as_needed : bool ) {
1665+ fn link_dylib_by_name ( & mut self , name : & str , _verbatim : bool , _as_needed : bool , _weak : bool ) {
16471666 self . hint_dynamic ( ) ;
16481667 self . link_or_cc_arg ( format ! ( "-l{name}" ) ) ;
16491668 }
16501669
1651- fn link_dylib_by_path ( & mut self , path : & Path , _as_needed : bool ) {
1670+ fn link_dylib_by_path ( & mut self , path : & Path , _as_needed : bool , _weak : bool ) {
16521671 self . hint_dynamic ( ) ;
16531672 self . link_or_cc_arg ( path) ;
16541673 }
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