Auto merge of #52353 - alexcrichton:wasm-custom-section, r=eddyb

rustc: Use link_section, not wasm_custom_section

This commit transitions definitions of custom sections on the wasm target from
the unstable `#[wasm_custom_section]` attribute to the
already-stable-for-other-targets `#[link_section]` attribute. Mostly the same
restrictions apply as before, except that this now applies only to statics.

Closes #51088

src/test/incremental/issue-49595/issue_49595.rs

@@ -15,7 +15,7 @@
 #![feature(rustc_attrs)]
 #![crate_type = "rlib"]
 
-#![rustc_partition_codegened(module="issue_49595-tests", cfg="cfail2")]
+#![rustc_partition_codegened(module="issue_49595-__test", cfg="cfail2")]
 #![rustc_partition_codegened(module="issue_49595-lit_test", cfg="cfail3")]
 
 mod tests {

src/test/run-make/wasm-custom-section/bar.rs

@@ -14,11 +14,11 @@
 
 extern crate foo;
 
-#[wasm_custom_section = "foo"]
-const A: [u8; 2] = [5, 6];
+#[link_section = "foo"]
+pub static A: [u8; 2] = [5, 6];
 
-#[wasm_custom_section = "baz"]
-const B: [u8; 2] = [7, 8];
+#[link_section = "baz"]
+pub static B: [u8; 2] = [7, 8];
 
 #[no_mangle]
 pub extern fn foo() {}

src/test/run-make/wasm-custom-section/foo.rs

@@ -12,8 +12,8 @@
 #![feature(wasm_custom_section)]
 #![deny(warnings)]
 
-#[wasm_custom_section = "foo"]
-const A: [u8; 2] = [1, 2];
+#[link_section = "foo"]
+pub static A: [u8; 2] = [1, 2];
 
-#[wasm_custom_section = "bar"]
-const B: [u8; 2] = [3, 4];
+#[link_section = "bar"]
+pub static B: [u8; 2] = [3, 4];

src/test/ui/feature-gate-wasm_custom_section.rs

@@ -1,14 +0,0 @@
-// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-#[wasm_custom_section = "foo"] //~ ERROR: attribute is currently unstable
-const A: [u8; 2] = [1, 2];
-
-fn main() {}

src/test/ui/feature-gate-wasm_custom_section.stderr

@@ -1,11 +0,0 @@
-error[E0658]: attribute is currently unstable (see issue #51088)
-  --> $DIR/feature-gate-wasm_custom_section.rs:11:1
-   |
-LL | #[wasm_custom_section = "foo"] //~ ERROR: attribute is currently unstable
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = help: add #![feature(wasm_custom_section)] to the crate attributes to enable
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0658`.

src/test/ui/wasm-custom-section-relocations.rs

@@ -8,12 +8,16 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(wasm_custom_section)]
+// only-wasm32
 
-#[wasm_custom_section] //~ ERROR: must be of the form
-const A: [u8; 1] = [0];
+#[link_section = "test"]
+pub static A: &[u8] = &[1]; //~ ERROR: no extra levels of indirection
 
-#[wasm_custom_section(foo)] //~ ERROR: must be of the form
-const B: [u8; 1] = [0];
+#[link_section = "test"]
+pub static B: [u8; 3] = [1, 2, 3];
 
-fn main() {}
+#[link_section = "test"]
+pub static C: usize = 3;
+
+#[link_section = "test"]
+pub static D: &usize = &C; //~ ERROR: no extra levels of indirection

src/test/ui/wasm-custom-section-relocations.stderr

@@ -0,0 +1,19 @@
+error[E0601]: `main` function not found in crate `wasm_custom_section_relocations`
+   |
+   = note: consider adding a `main` function to `$DIR/wasm-custom-section-relocations.rs`
+
+error: statics with a custom `#[link_section]` must be a simple list of bytes on the wasm target with no extra levels of indirection such as references
+  --> $DIR/wasm-custom-section-relocations.rs:14:1
+   |
+LL | pub static A: &[u8] = &[1]; //~ ERROR: no extra levels of indirection
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: statics with a custom `#[link_section]` must be a simple list of bytes on the wasm target with no extra levels of indirection such as references
+  --> $DIR/wasm-custom-section-relocations.rs:23:1
+   |
+LL | pub static D: &usize = &C; //~ ERROR: no extra levels of indirection
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0601`.

src/test/ui/wasm-custom-section/malformed.stderr

@@ -1,14 +0,0 @@
-error: must be of the form #[wasm_custom_section = "foo"]
-  --> $DIR/malformed.rs:13:1
-   |
-LL | #[wasm_custom_section] //~ ERROR: must be of the form
-   | ^^^^^^^^^^^^^^^^^^^^^^
-
-error: must be of the form #[wasm_custom_section = "foo"]
-  --> $DIR/malformed.rs:16:1
-   |
-LL | #[wasm_custom_section(foo)] //~ ERROR: must be of the form
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: aborting due to 2 previous errors
-

src/test/ui/wasm-custom-section/not-const.rs

@@ -1,29 +0,0 @@
-// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-#![feature(wasm_custom_section)]
-
-#[wasm_custom_section = "foo"] //~ ERROR: only allowed on consts
-static A: [u8; 2] = [1, 2];
-
-#[wasm_custom_section = "foo"] //~ ERROR: only allowed on consts
-struct B {}
-
-#[wasm_custom_section = "foo"] //~ ERROR: only allowed on consts
-enum C {}
-
-#[wasm_custom_section = "foo"] //~ ERROR: only allowed on consts
-impl B {}
-
-#[wasm_custom_section = "foo"] //~ ERROR: only allowed on consts
-mod d {}
-
-#[wasm_custom_section = "foo"] //~ ERROR: only allowed on consts
-fn main() {}

src/test/ui/wasm-custom-section/not-const.stderr

@@ -1,38 +0,0 @@
-error: only allowed on consts
-  --> $DIR/not-const.rs:13:1
-   |
-LL | #[wasm_custom_section = "foo"] //~ ERROR: only allowed on consts
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: only allowed on consts
-  --> $DIR/not-const.rs:16:1
-   |
-LL | #[wasm_custom_section = "foo"] //~ ERROR: only allowed on consts
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: only allowed on consts
-  --> $DIR/not-const.rs:19:1
-   |
-LL | #[wasm_custom_section = "foo"] //~ ERROR: only allowed on consts
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: only allowed on consts
-  --> $DIR/not-const.rs:22:1
-   |
-LL | #[wasm_custom_section = "foo"] //~ ERROR: only allowed on consts
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: only allowed on consts
-  --> $DIR/not-const.rs:25:1
-   |
-LL | #[wasm_custom_section = "foo"] //~ ERROR: only allowed on consts
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: only allowed on consts
-  --> $DIR/not-const.rs:28:1
-   |
-LL | #[wasm_custom_section = "foo"] //~ ERROR: only allowed on consts
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: aborting due to 6 previous errors
-

src/test/ui/wasm-custom-section/not-slice.rs

@@ -1,22 +0,0 @@
-// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-#![feature(wasm_custom_section)]
-
-#[wasm_custom_section = "foo"]
-const A: u8 = 0; //~ ERROR: must be an array of bytes
-
-#[wasm_custom_section = "foo"]
-const B: &[u8] = &[0]; //~ ERROR: must be an array of bytes
-
-#[wasm_custom_section = "foo"]
-const C: &[u8; 1] = &[0]; //~ ERROR: must be an array of bytes
-
-fn main() {}

src/test/ui/wasm-custom-section/not-slice.stderr

@@ -1,20 +0,0 @@
-error: must be an array of bytes like `[u8; N]`
-  --> $DIR/not-slice.rs:14:1
-   |
-LL | const A: u8 = 0; //~ ERROR: must be an array of bytes
-   | ^^^^^^^^^^^^^^^^
-
-error: must be an array of bytes like `[u8; N]`
-  --> $DIR/not-slice.rs:17:1
-   |
-LL | const B: &[u8] = &[0]; //~ ERROR: must be an array of bytes
-   | ^^^^^^^^^^^^^^^^^^^^^^
-
-error: must be an array of bytes like `[u8; N]`
-  --> $DIR/not-slice.rs:20:1
-   |
-LL | const C: &[u8; 1] = &[0]; //~ ERROR: must be an array of bytes
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: aborting due to 3 previous errors
-