Rollup merge of rust-lang#118644 - madsmtm:macos-weak-linking-test, r=b-naber

Add test for Apple's `-weak_framework` linker argument

The [`-weak_framework`](https://developer.apple.com/library/archive/documentation/MacOSX/Conceptual/BPFrameworks/Concepts/WeakLinking.html) linker argument can sometimes be useful to reduce startup times, and to link newer frameworks while still having older deployment targets.

So I made a test to ensure that it continues to work.

Discussed in rust-lang#99427.

Author: GuillaumeGomez

tests/run-make/link-framework/Makefile

@@ -0,0 +1,23 @@
+# only-macos
+#
+# Check that linking to a framework actually makes it to the linker.
+
+include ../tools.mk
+
+all:
+	$(RUSTC) dep-link-framework.rs
+	$(RUSTC) dep-link-weak-framework.rs
+
+	$(RUSTC) empty.rs
+	otool -L $(TMPDIR)/no-link | $(CGREP) -v CoreFoundation
+
+	$(RUSTC) link-framework.rs
+	otool -L $(TMPDIR)/link-framework | $(CGREP) CoreFoundation | $(CGREP) -v weak
+
+	$(RUSTC) link-weak-framework.rs
+	otool -L $(TMPDIR)/link-weak-framework | $(CGREP) CoreFoundation | $(CGREP) weak
+
+# When linking the framework both normally, and weakly, the weak linking takes preference
+
+	$(RUSTC) link-both.rs
+	otool -L $(TMPDIR)/link-both | $(CGREP) CoreFoundation | $(CGREP) weak

tests/run-make/link-framework/dep-link-framework.rs

@@ -0,0 +1,4 @@
+#![crate_type = "rlib"]
+
+#[link(name = "CoreFoundation", kind = "framework")]
+extern "C" {}

tests/run-make/link-framework/dep-link-weak-framework.rs

@@ -0,0 +1,6 @@
+#![crate_type = "rlib"]
+#![feature(link_arg_attribute)]
+
+#[link(name = "-weak_framework", kind = "link-arg", modifiers = "+verbatim")]
+#[link(name = "CoreFoundation", kind = "link-arg", modifiers = "+verbatim")]
+extern "C" {}

tests/run-make/link-framework/empty.rs

@@ -0,0 +1 @@
+fn main() {}

tests/run-make/link-framework/link-both.rs

@@ -0,0 +1,4 @@
+extern crate dep_link_framework;
+extern crate dep_link_weak_framework;
+
+fn main() {}

tests/run-make/link-framework/link-framework.rs

@@ -0,0 +1,3 @@
+extern crate dep_link_framework;
+
+fn main() {}

tests/run-make/link-framework/link-weak-framework.rs

@@ -0,0 +1,3 @@
+extern crate dep_link_weak_framework;
+
+fn main() {}

tests/run-pass-valgrind/osx-frameworks.rs

@@ -0,0 +1,12 @@
+error: linking with `cc` failed: exit status: 1
+   |
+   = note: [linker command]
+   = note: ld: warning: search path '$TEST_BUILD_DIR/linkage-attr/framework.omit/auxiliary' not found
+           ld: Undefined symbols:
+             _CFRunLoopGetTypeID, referenced from:
+                 framework::main::HASH in framework.framework.HASH-cgu.0.rcgu.o
+           clang: error: linker command failed with exit code 1 (use -v to see invocation)
+           
+
+error: aborting due to 1 previous error
+

tests/ui/linkage-attr/framework.omit.stderr

@@ -0,0 +1,27 @@
+// Check that linking frameworks on Apple platforms works.
+// only-macos
+// revisions: omit link weak both
+// [omit]build-fail
+// [link]run-pass
+// [weak]run-pass
+// [both]run-pass
+// normalize-stderr-test: "note: env .*" -> "note: [linker command]"
+// normalize-stderr-test: "framework::main::\w* in framework\.framework\.\w*-cgu\.0\.rcgu\.o" -> "framework::main::HASH in framework.framework.HASH-cgu.0.rcgu.o"
+
+#![cfg_attr(any(weak, both), feature(link_arg_attribute))]
+
+#[cfg_attr(any(link, both), link(name = "CoreFoundation", kind = "framework"))]
+#[cfg_attr(
+    any(weak, both),
+    link(name = "-weak_framework", kind = "link-arg", modifiers = "+verbatim"),
+    link(name = "CoreFoundation", kind = "link-arg", modifiers = "+verbatim")
+)]
+extern "C" {
+    fn CFRunLoopGetTypeID() -> core::ffi::c_ulong;
+}
+
+pub fn main() {
+    unsafe {
+        CFRunLoopGetTypeID();
+    }
+}