Auto merge of #68277 - michaelwoerister:re-export-dylib-instances, r=alexcrichton

Make sure that all upstream generics get re-exported from Rust dylibs.

This PR contains a fix for #67276. Rust dylibs would not re-export all generic instances when compiling with `-Zshare-generics=on` (=default for debug builds) which could lead to situations where the compiler expected certain generic instances to be available but then the linker would not find them.

### TODO
- [x] Write a regression test based on the description [here](https://github.com/rust-lang/rust/issues/67276#issuecomment-574613457).
- [x] Find out if this also fixes other issues related to https://github.com/rust-lang/rust/issues/64319.

r? @alexcrichton ~~(once the TODOs are done)~~
cc @pnkfelix @AlexKornitzer

10 files changed, 127 insertions, 0 deletions

diff --git a/src/test/run-make-fulldeps/issue64319/Makefile b/src/test/run-make-fulldeps/issue64319/Makefile
new file mode 100644
index 00000000000..5592f5a71ff
--- /dev/null
+++ b/src/test/run-make-fulldeps/issue64319/Makefile
@@ -0,0 +1,39 @@
+-include ../../run-make-fulldeps/tools.mk
+
+# Different optimization levels imply different values for `-Zshare-generics`,
+# so try out a whole bunch of combinations to make sure everything is compatible
+all:
+	# First up, try some defaults
+	$(RUSTC) --crate-type rlib foo.rs
+	$(RUSTC) --crate-type dylib bar.rs -C opt-level=3
+
+	# Next try mixing up some things explicitly
+	$(RUSTC) --crate-type rlib foo.rs -Z share-generics=no
+	$(RUSTC) --crate-type dylib bar.rs -Z share-generics=no
+	$(RUSTC) --crate-type rlib foo.rs -Z share-generics=no
+	$(RUSTC) --crate-type dylib bar.rs -Z share-generics=yes
+	$(RUSTC) --crate-type rlib foo.rs -Z share-generics=yes
+	$(RUSTC) --crate-type dylib bar.rs -Z share-generics=no
+	$(RUSTC) --crate-type rlib foo.rs -Z share-generics=yes
+	$(RUSTC) --crate-type dylib bar.rs -Z share-generics=yes
+
+	# Now combine a whole bunch of options together
+	$(RUSTC) --crate-type rlib foo.rs
+	$(RUSTC) --crate-type dylib bar.rs
+	$(RUSTC) --crate-type dylib bar.rs -Z share-generics=no
+	$(RUSTC) --crate-type dylib bar.rs -Z share-generics=yes
+	$(RUSTC) --crate-type dylib bar.rs -C opt-level=1
+	$(RUSTC) --crate-type dylib bar.rs -C opt-level=1 -Z share-generics=no
+	$(RUSTC) --crate-type dylib bar.rs -C opt-level=1 -Z share-generics=yes
+	$(RUSTC) --crate-type dylib bar.rs -C opt-level=2
+	$(RUSTC) --crate-type dylib bar.rs -C opt-level=2 -Z share-generics=no
+	$(RUSTC) --crate-type dylib bar.rs -C opt-level=2 -Z share-generics=yes
+	$(RUSTC) --crate-type dylib bar.rs -C opt-level=3
+	$(RUSTC) --crate-type dylib bar.rs -C opt-level=3 -Z share-generics=no
+	$(RUSTC) --crate-type dylib bar.rs -C opt-level=3 -Z share-generics=yes
+	$(RUSTC) --crate-type dylib bar.rs -C opt-level=s
+	$(RUSTC) --crate-type dylib bar.rs -C opt-level=s -Z share-generics=no
+	$(RUSTC) --crate-type dylib bar.rs -C opt-level=s -Z share-generics=yes
+	$(RUSTC) --crate-type dylib bar.rs -C opt-level=z
+	$(RUSTC) --crate-type dylib bar.rs -C opt-level=z -Z share-generics=no
+	$(RUSTC) --crate-type dylib bar.rs -C opt-level=z -Z share-generics=yes
diff --git a/src/test/run-make-fulldeps/issue64319/bar.rs b/src/test/run-make-fulldeps/issue64319/bar.rs
new file mode 100644
index 00000000000..3895c0b6cdb
--- /dev/null
+++ b/src/test/run-make-fulldeps/issue64319/bar.rs
@@ -0,0 +1,5 @@
+extern crate foo;
+
+pub fn bar() {
+    foo::foo();
+}
diff --git a/src/test/run-make-fulldeps/issue64319/foo.rs b/src/test/run-make-fulldeps/issue64319/foo.rs
new file mode 100644
index 00000000000..c54a238e9ad
--- /dev/null
+++ b/src/test/run-make-fulldeps/issue64319/foo.rs
@@ -0,0 +1,9 @@
+pub fn foo() {
+    bar::<usize>();
+}
+
+pub fn bar<T>() {
+    baz();
+}
+
+fn baz() {}
diff --git a/src/test/run-make-fulldeps/share-generics-dylib/Makefile b/src/test/run-make-fulldeps/share-generics-dylib/Makefile
new file mode 100644
index 00000000000..c6b5efcb4cd
--- /dev/null
+++ b/src/test/run-make-fulldeps/share-generics-dylib/Makefile
@@ -0,0 +1,22 @@
+# This test makes sure all generic instances get re-exported from Rust dylibs for use by
+# `-Zshare-generics`. There are two rlibs (`instance_provider_a` and `instance_provider_b`)
+# which both provide an instance of `Cell<i32>::set`. There is `instance_user_dylib` which is
+# supposed to re-export both these instances, and then there are `instance_user_a_rlib` and
+# `instance_user_b_rlib` which each rely on a specific instance to be available.
+#
+# In the end everything is linked together into `linked_leaf`. If `instance_user_dylib` does
+# not export both then we'll get an `undefined reference` error for one of the instances.
+#
+# This is regression test for https://github.com/rust-lang/rust/issues/67276.
+
+-include ../../run-make-fulldeps/tools.mk
+
+COMMON_ARGS=-Cprefer-dynamic -Zshare-generics=yes -Ccodegen-units=1 -Zsymbol-mangling-version=v0
+
+all:
+	$(RUSTC) instance_provider_a.rs $(COMMON_ARGS) --crate-type=rlib
+	$(RUSTC) instance_provider_b.rs $(COMMON_ARGS) --crate-type=rlib
+	$(RUSTC) instance_user_dylib.rs $(COMMON_ARGS) --crate-type=dylib
+	$(RUSTC) instance_user_a_rlib.rs $(COMMON_ARGS) --crate-type=rlib
+	$(RUSTC) instance_user_b_rlib.rs $(COMMON_ARGS) --crate-type=rlib
+	$(RUSTC) linked_leaf.rs $(COMMON_ARGS) --crate-type=bin
diff --git a/src/test/run-make-fulldeps/share-generics-dylib/instance_provider_a.rs b/src/test/run-make-fulldeps/share-generics-dylib/instance_provider_a.rs
new file mode 100644
index 00000000000..b4e125ac052
--- /dev/null
+++ b/src/test/run-make-fulldeps/share-generics-dylib/instance_provider_a.rs
@@ -0,0 +1,6 @@
+use std::cell::Cell;
+
+pub fn foo() {
+    let a: Cell<i32> = Cell::new(1);
+    a.set(123);
+}
diff --git a/src/test/run-make-fulldeps/share-generics-dylib/instance_provider_b.rs b/src/test/run-make-fulldeps/share-generics-dylib/instance_provider_b.rs
new file mode 100644
index 00000000000..f613db873e6
--- /dev/null
+++ b/src/test/run-make-fulldeps/share-generics-dylib/instance_provider_b.rs
@@ -0,0 +1,6 @@
+use std::cell::Cell;
+
+pub fn foo() {
+    let b: Cell<i32> = Cell::new(1);
+    b.set(123);
+}
diff --git a/src/test/run-make-fulldeps/share-generics-dylib/instance_user_a_rlib.rs b/src/test/run-make-fulldeps/share-generics-dylib/instance_user_a_rlib.rs
new file mode 100644
index 00000000000..c8e6ab95cf9
--- /dev/null
+++ b/src/test/run-make-fulldeps/share-generics-dylib/instance_user_a_rlib.rs
@@ -0,0 +1,9 @@
+extern crate instance_provider_a as upstream;
+use std::cell::Cell;
+
+pub fn foo() {
+    upstream::foo();
+
+    let b: Cell<i32> = Cell::new(1);
+    b.set(123);
+}
diff --git a/src/test/run-make-fulldeps/share-generics-dylib/instance_user_b_rlib.rs b/src/test/run-make-fulldeps/share-generics-dylib/instance_user_b_rlib.rs
new file mode 100644
index 00000000000..7c34af6d0dc
--- /dev/null
+++ b/src/test/run-make-fulldeps/share-generics-dylib/instance_user_b_rlib.rs
@@ -0,0 +1,9 @@
+extern crate instance_provider_b as upstream;
+use std::cell::Cell;
+
+pub fn foo() {
+    upstream::foo();
+
+    let b: Cell<i32> = Cell::new(1);
+    b.set(123);
+}
diff --git a/src/test/run-make-fulldeps/share-generics-dylib/instance_user_dylib.rs b/src/test/run-make-fulldeps/share-generics-dylib/instance_user_dylib.rs
new file mode 100644
index 00000000000..7c8368eec65
--- /dev/null
+++ b/src/test/run-make-fulldeps/share-generics-dylib/instance_user_dylib.rs
@@ -0,0 +1,7 @@
+extern crate instance_provider_a;
+extern crate instance_provider_b;
+
+pub fn foo() {
+    instance_provider_a::foo();
+    instance_provider_b::foo();
+}
diff --git a/src/test/run-make-fulldeps/share-generics-dylib/linked_leaf.rs b/src/test/run-make-fulldeps/share-generics-dylib/linked_leaf.rs
new file mode 100644
index 00000000000..e510dad691c
--- /dev/null
+++ b/src/test/run-make-fulldeps/share-generics-dylib/linked_leaf.rs
@@ -0,0 +1,15 @@
+extern crate instance_user_dylib;
+extern crate instance_user_a_rlib;
+extern crate instance_user_b_rlib;
+
+use std::cell::Cell;
+
+fn main() {
+
+    instance_user_a_rlib::foo();
+    instance_user_b_rlib::foo();
+    instance_user_dylib::foo();
+
+    let a: Cell<i32> = Cell::new(1);
+    a.set(123);
+}