Upgrade Emscripten targets to use upstream LLVM backend

- Compatible with Emscripten 1.38.46-upstream or later upstream.
 - Refactors the Emscripten target spec to share code with other wasm
   targets.
 - Replaces the old incorrect wasm32 C call ABI with the correct one,
   preserving the old one as wasm32_bindgen_compat for wasm-bindgen
   compatibility.
 - Updates the varargs ABI used by Emscripten and deletes the old one.
 - Removes the obsolete wasm32-experimental-emscripten target.
 - Uses EMCC_CFLAGS on CI to avoid the timeout problems with #63649.

src/test/ui/abi/statics/static-mut-foreign.rs

@@ -5,6 +5,10 @@
 
 // ignore-wasm32-bare no libc to test ffi with
 
+// FIXME: This will work on emscripten once libc is updated to include
+// rust-lang/libc/#1478
+// ignore-emscripten libc type mismatch
+
 #![feature(rustc_private)]
 
 extern crate libc;

src/test/ui/async-await/async-fn-size-moved-locals.rs

@@ -7,7 +7,7 @@
 //
 // See issue #59123 for a full explanation.
 
-// ignore-wasm32-bare (sizes don't match)
+// ignore-emscripten (sizes don't match)
 // run-pass
 
 // edition:2018

src/test/ui/async-await/async-fn-size-uninit-locals.rs

@@ -4,7 +4,7 @@
 // What we don't want to see is the wrong multiple of 1024 (the size of `Big`)
 // being reflected in the size.
 
-// ignore-wasm32-bare (sizes don't match)
+// ignore-emscripten (sizes don't match)
 // run-pass
 
 // edition:2018

src/test/ui/async-await/issue-60709.rs

@@ -3,6 +3,7 @@
 // compile-flags: -Copt-level=z -Cdebuginfo=2 --edition=2018
 
 // run-pass
+// ignore-asmjs wasm2js does not support source maps yet
 
 use std::future::Future;
 use std::task::Poll;

src/test/ui/binding/fn-arg-incomplete-pattern-drop-order.rs

@@ -2,7 +2,7 @@
 // Check that partially moved from function parameters are dropped after the
 // named bindings that move from them.
 
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 
 use std::{panic, cell::RefCell};
 

src/test/ui/binding/match-arm-statics.rs

@@ -1,6 +1,7 @@
 // run-pass
 #![allow(dead_code)]
 // compile-flags: -g
+// ignore-asmjs wasm2js does not support source maps yet
 
 #[derive(PartialEq, Eq)]
 struct NewBool(bool);

src/test/ui/builtin-clone-unwind.rs

@@ -2,7 +2,7 @@
 
 #![allow(unused_variables)]
 #![allow(unused_imports)]
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 
 // Test that builtin implementations of `Clone` cleanup everything
 // in case of unwinding.

src/test/ui/catch-unwind-bang.rs

@@ -1,5 +1,5 @@
 // run-pass
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 
 fn worker() -> ! {
     panic!()

src/test/ui/consts/const-int-saturating-arith.rs

@@ -1,5 +1,4 @@
 // run-pass
-// ignore-emscripten no i128 support
 #![feature(const_saturating_int_methods)]
 
 const INT_U32_NO: u32 = (42 as u32).saturating_add(2);

src/test/ui/debuginfo-lto.rs

@@ -7,6 +7,7 @@
 // aux-build:debuginfo-lto-aux.rs
 // compile-flags: -C lto -g
 // no-prefer-dynamic
+// ignore-asmjs wasm2js does not support source maps yet
 
 extern crate debuginfo_lto_aux;
 

src/test/ui/drop/dynamic-drop-async.rs

@@ -5,7 +5,7 @@
 
 // run-pass
 // edition:2018
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 
 #![feature(slice_patterns)]
 #![allow(unused)]

src/test/ui/drop/dynamic-drop.rs

@@ -2,7 +2,7 @@
 #![allow(unused_assignments)]
 #![allow(unused_variables)]
 
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 
 #![feature(generators, generator_trait, untagged_unions)]
 #![feature(slice_patterns)]

src/test/ui/extern/extern-const.fixed

@@ -5,7 +5,8 @@
 // compile. To sidestep this by using one that *is* defined.
 
 // run-rustfix
-// ignore-wasm32 no external library to link to.
+// ignore-wasm32-bare no external library to link to.
+// ignore-asmjs wasm2js does not support source maps yet
 // compile-flags: -g
 #![feature(rustc_private)]
 extern crate libc;

src/test/ui/extern/extern-const.rs

@@ -5,7 +5,8 @@
 // compile. To sidestep this by using one that *is* defined.
 
 // run-rustfix
-// ignore-wasm32 no external library to link to.
+// ignore-wasm32-bare no external library to link to.
+// ignore-asmjs wasm2js does not support source maps yet
 // compile-flags: -g
 #![feature(rustc_private)]
 extern crate libc;

src/test/ui/extern/extern-const.stderr

@@ -1,5 +1,5 @@
 error: extern items cannot be `const`
-  --> $DIR/extern-const.rs:15:5
+  --> $DIR/extern-const.rs:16:5
    |
 LL |     const rust_dbg_static_mut: libc::c_int;
    |     ^^^^^ help: try using a static value: `static`

src/test/ui/feature-gates/feature-gate-unwind-attributes.rs

@@ -1,3 +1,4 @@
+// ignore-emscripten compiled with panic=abort by default
 // compile-flags: -C no-prepopulate-passes -Cpasses=name-anon-globals
 
 #![crate_type = "lib"]

src/test/ui/generator/issue-58888.rs

@@ -1,5 +1,6 @@
 // run-pass
 // compile-flags: -g
+// ignore-asmjs wasm2js does not support source maps yet
 
 #![feature(generators, generator_trait)]
 

src/test/ui/generator/panic-drops.rs

@@ -1,6 +1,6 @@
 // run-pass
 
-// ignore-wasm32-bare compiled as panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 
 #![feature(generators, generator_trait)]
 

src/test/ui/generator/panic-safe.rs

@@ -1,6 +1,6 @@
 // run-pass
 
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 
 #![feature(generators, generator_trait)]
 

src/test/ui/generator/resume-after-return.rs

@@ -1,6 +1,6 @@
 // run-pass
 
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 
 #![feature(generators, generator_trait)]
 

src/test/ui/generator/size-moved-locals.rs

@@ -11,6 +11,7 @@
 
 // edition:2018
 // ignore-wasm32 issue #62807
+// ignore-asmjs issue #62807
 
 #![feature(generators, generator_trait)]
 

src/test/ui/intrinsics/intrinsics-integer.rs

@@ -1,5 +1,4 @@
 // run-pass
-// ignore-emscripten no i128 support
 
 #![feature(intrinsics)]
 

src/test/ui/issues/issue-14875.rs

@@ -1,5 +1,5 @@
 // run-pass
-// ignore-wasm32-bare always compiled as panic=abort right now
+// ignore-emscripten compiled with panic=abort by default
 
 // Check that values are not leaked when a dtor panics (#14875)
 

src/test/ui/issues/issue-23477.rs

@@ -1,4 +1,5 @@
 // build-pass
+// ignore-asmjs wasm2js does not support source maps yet
 // compile-flags: -g
 
 pub struct Dst {

src/test/ui/issues/issue-24687-embed-debuginfo/main.rs

@@ -1,6 +1,7 @@
 // run-pass
 // aux-build:issue-24687-lib.rs
 // compile-flags:-g
+// ignore-asmjs wasm2js does not support source maps yet
 
 extern crate issue_24687_lib as d;
 

src/test/ui/issues/issue-24945-repeat-dash-opts.rs

@@ -3,6 +3,7 @@
 // as options to the compiler.
 
 // compile-flags:-g -g -O -O
+// ignore-asmjs wasm2js does not support source maps yet
 
 fn main() {
     assert_eq!(1, 1);

src/test/ui/issues/issue-26484.rs

@@ -1,5 +1,6 @@
 // run-pass
 // compile-flags:-g
+// ignore-asmjs wasm2js does not support source maps yet
 
 fn helper<F: FnOnce(usize) -> bool>(_f: F) {
     print!("");

src/test/ui/issues/issue-29948.rs

@@ -1,5 +1,5 @@
 // run-pass
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 
 use std::panic;
 

src/test/ui/issues/issue-33096.rs

@@ -1,5 +1,6 @@
 // run-pass
 // compile-flags: -g
+// ignore-asmjs wasm2js does not support source maps yet
 
 use std::ops::Deref;
 

src/test/ui/issues/issue-33992.rs

@@ -1,7 +1,7 @@
 // run-pass
 // ignore-windows
 // ignore-macos
-// ignore-wasm32-bare common linkage not implemented right now
+// ignore-emscripten common linkage not implemented right now
 
 #![feature(linkage)]
 

src/test/ui/issues/issue-34569.rs

@@ -1,5 +1,6 @@
 // run-pass
 // compile-flags:-g
+// ignore-asmjs wasm2js does not support source maps yet
 
 // In this test we just want to make sure that the code below does not lead to
 // a debuginfo verification assertion during compilation. This was caused by the

src/test/ui/issues/issue-36856.rs

@@ -2,6 +2,7 @@
 // Regression test for #36856.
 
 // compile-flags:-g
+// ignore-asmjs wasm2js does not support source maps yet
 
 fn g() -> bool {
     false

src/test/ui/issues/issue-42210.rs

@@ -2,6 +2,7 @@
 // Regression test for #42210.
 
 // compile-flags: -g
+// ignore-asmjs wasm2js does not support source maps yet
 
 trait Foo {
     fn foo() { }

src/test/ui/issues/issue-43853.rs

@@ -1,5 +1,5 @@
 // run-pass
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 
 use std::panic;
 

src/test/ui/issues/issue-45731.rs

@@ -1,6 +1,7 @@
 // run-pass
 #![allow(unused_variables)]
 // compile-flags:--test -g
+// ignore-asmjs wasm2js does not support source maps yet
 
 #[cfg(target_os = "macos")]
 #[test]

src/test/ui/issues/issue-46519.rs

@@ -1,6 +1,8 @@
 // run-pass
 // compile-flags:--test -O
 
+// ignore-emscripten compiled with panic=abort by default
+
 #[test]
 #[should_panic(expected = "creating inhabited type")]
 fn test() {

src/test/ui/issues/issue-48508.rs

@@ -8,6 +8,7 @@
 
 // compile-flags:-g
 // ignore-pretty issue #37195
+// ignore-asmjs wasm2js does not support source maps yet
 
 #![feature(non_ascii_idents)]
 

src/test/ui/issues/issue-49579.rs

@@ -1,5 +1,4 @@
 // build-pass (FIXME(62277): could be check-pass?)
-// ignore-emscripten no i128 support
 
 fn fibs(n: u32) -> impl Iterator<Item=u128> {
     (0 .. n)

src/test/ui/issues/issue-58463.rs

@@ -1,5 +1,7 @@
 // run-pass
 // compile-flags:-C debuginfo=2
+// ignore-asmjs wasm2js does not support source maps yet
+
 fn foo() -> impl Copy {
     foo
 }

src/test/ui/iterators/iter-count-overflow-debug.rs

@@ -1,6 +1,6 @@
 // run-pass
 // only-32bit too impatient for 2⁶⁴ items
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 // compile-flags: -C debug_assertions=yes -C opt-level=3
 
 use std::panic;

src/test/ui/iterators/iter-position-overflow-debug.rs

@@ -1,6 +1,6 @@
 // run-pass
 // only-32bit too impatient for 2⁶⁴ items
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 // compile-flags: -C debug_assertions=yes -C opt-level=3
 
 use std::panic;

src/test/ui/iterators/iter-step-overflow-debug.rs

@@ -1,5 +1,5 @@
 // run-pass
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 // compile-flags: -C debug_assertions=yes
 
 use std::panic;

src/test/ui/iterators/iter-sum-overflow-debug.rs

@@ -1,5 +1,5 @@
 // run-pass
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 // compile-flags: -C debug_assertions=yes
 
 use std::panic;

src/test/ui/iterators/iter-sum-overflow-overflow-checks.rs

@@ -1,5 +1,5 @@
 // run-pass
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 // compile-flags: -C overflow-checks
 
 use std::panic;

src/test/ui/macros/macro-comma-behavior-rpass.rs

@@ -13,6 +13,8 @@
 // compile-flags: --test -C debug_assertions=yes
 // revisions: std core
 
+// ignore-emscripten compiled with panic=abort by default
+
 #![cfg_attr(core, no_std)]
 
 #[cfg(std)] use std::fmt;

src/test/ui/mir/mir_calls_to_shims.rs

@@ -1,5 +1,5 @@
 // run-pass
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 
 #![feature(fn_traits)]
 #![feature(never_type)]

src/test/ui/mir/mir_drop_order.rs

@@ -1,5 +1,5 @@
 // run-pass
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 
 use std::cell::RefCell;
 use std::panic;

src/test/ui/never_type/panic-uninitialized-zeroed.rs

@@ -1,5 +1,5 @@
 // run-pass
-// ignore-wasm32-bare always compiled as panic=abort right now and this requires unwinding
+// ignore-emscripten compiled with panic=abort by default
 // This test checks that instantiating an uninhabited type via `mem::{uninitialized,zeroed}` results
 // in a runtime panic.
 

src/test/ui/numbers-arithmetic/float-int-invalid-const-cast.rs

@@ -1,5 +1,4 @@
 // run-pass
-// ignore-emscripten no i128 support
 
 #![deny(const_err)]
 

src/test/ui/numbers-arithmetic/i128.rs

@@ -1,9 +1,6 @@
 // run-pass
 #![allow(overflowing_literals)]
 
-// ignore-emscripten i128 doesn't work
-
-
 #![feature(test)]
 
 extern crate test;

src/test/ui/numbers-arithmetic/next-power-of-two-overflow-debug.rs

@@ -1,6 +1,6 @@
 // run-pass
 // compile-flags: -C debug_assertions=yes
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 // ignore-emscripten dies with an LLVM error
 
 use std::panic;

src/test/ui/numbers-arithmetic/u128-as-f32.rs

@@ -1,5 +1,4 @@
 // run-pass
-// ignore-emscripten u128 not supported
 
 #![feature(test)]
 #![deny(overflowing_literals)]

src/test/ui/numbers-arithmetic/u128.rs

@@ -1,6 +1,4 @@
 // run-pass
-// ignore-emscripten u128 not supported
-
 
 #![feature(test)]
 

src/test/ui/panic-runtime/transitive-link-a-bunch.rs

@@ -4,7 +4,7 @@
 // aux-build:wants-panic-runtime-abort.rs
 // aux-build:panic-runtime-lang-items.rs
 // error-pattern: is not compiled with this crate's panic strategy `unwind`
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 
 #![no_std]
 #![no_main]

src/test/ui/panic-runtime/want-unwind-got-abort.rs

@@ -1,7 +1,7 @@
 // error-pattern:is incompatible with this crate's strategy of `unwind`
 // aux-build:panic-runtime-abort.rs
 // aux-build:panic-runtime-lang-items.rs
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 
 #![no_std]
 #![no_main]

src/test/ui/panic-runtime/want-unwind-got-abort2.rs

@@ -2,7 +2,7 @@
 // aux-build:panic-runtime-abort.rs
 // aux-build:wants-panic-runtime-abort.rs
 // aux-build:panic-runtime-lang-items.rs
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 
 #![no_std]
 #![no_main]

src/test/ui/proc-macro/expand-with-a-macro.rs

@@ -1,7 +1,7 @@
 // run-pass
 // aux-build:expand-with-a-macro.rs
 
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 
 #![deny(warnings)]
 

src/test/ui/reachable-unnameable-items.rs

@@ -1,5 +1,5 @@
 // run-pass
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 // aux-build:reachable-unnameable-items.rs
 
 extern crate reachable_unnameable_items;

src/test/ui/rfc-1937-termination-trait/termination-trait-in-test.rs

@@ -1,6 +1,8 @@
 // compile-flags: --test
 // run-pass
 
+// ignore-emscripten compiled with panic=abort by default
+
 #![feature(test)]
 
 extern crate test;

src/test/ui/rfcs/rfc1857-drop-order.rs

@@ -1,5 +1,5 @@
 // run-pass
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 
 #![allow(dead_code, unreachable_code)]
 

src/test/ui/sepcomp/sepcomp-lib-lto.rs

@@ -4,6 +4,7 @@
 
 // aux-build:sepcomp_lib.rs
 // compile-flags: -C lto -g
+// ignore-asmjs wasm2js does not support source maps yet
 // no-prefer-dynamic
 
 extern crate sepcomp_lib;

src/test/ui/test-attrs/test-allow-fail-attr.rs

@@ -1,5 +1,5 @@
 // run-pass
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 // compile-flags: --test
 #![feature(allow_fail)]
 

src/test/ui/test-attrs/test-should-fail-good-message.rs

@@ -1,5 +1,5 @@
 // run-pass
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 // compile-flags: --test
 #[test]
 #[should_panic(expected = "foo")]

src/test/ui/unboxed-closures/unboxed-closures-unique-type-id.rs

@@ -10,6 +10,7 @@
 // This is a regression test for issue #17021.
 //
 // compile-flags: -g
+// ignore-asmjs wasm2js does not support source maps yet
 
 use std::ptr;