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.

1 files changed, 2 insertions, 5 deletions

diff --git a/src/librustc_codegen_ssa/back/write.rs b/src/librustc_codegen_ssa/back/write.rs
index 5339134a2a8..0ef1844b5ac 100644
--- a/src/librustc_codegen_ssa/back/write.rs
+++ b/src/librustc_codegen_ssa/back/write.rs
@@ -143,15 +143,12 @@ impl ModuleConfig {
         // Copy what clang does by turning on loop vectorization at O2 and
         // slp vectorization at O3. Otherwise configure other optimization aspects
         // of this pass manager builder.
-        // Turn off vectorization for emscripten, as it's not very well supported.
         self.vectorize_loop = !sess.opts.cg.no_vectorize_loops &&
                              (sess.opts.optimize == config::OptLevel::Default ||
-                              sess.opts.optimize == config::OptLevel::Aggressive) &&
-                             !sess.target.target.options.is_like_emscripten;
+                              sess.opts.optimize == config::OptLevel::Aggressive);
 
         self.vectorize_slp = !sess.opts.cg.no_vectorize_slp &&
-                            sess.opts.optimize == config::OptLevel::Aggressive &&
-                            !sess.target.target.options.is_like_emscripten;
+                            sess.opts.optimize == config::OptLevel::Aggressive;
 
         // Some targets (namely, NVPTX) interact badly with the MergeFunctions
         // pass. This is because MergeFunctions can generate new function calls