Gate compiler changes on -Zemscripten-wasm-eh

Author: hoodmane

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -109,9 +109,12 @@ unsafe fn configure_llvm(sess: &Session) {
             add("-wasm-enable-eh", false);
         }
 
-        // if sess.target.os == "emscripten" && sess.panic_strategy() == PanicStrategy::Unwind {
-        //     add("-enable-emscripten-cxx-exceptions", false);
-        // }
+        if sess.target.os == "emscripten"
+            && !sess.opts.unstable_opts.emscripten_wasm_eh
+            && sess.panic_strategy() == PanicStrategy::Unwind
+        {
+            add("-enable-emscripten-cxx-exceptions", false);
+        }
 
         // HACK(eddyb) LLVM inserts `llvm.assume` calls to preserve align attributes
         // during inlining. Unfortunately these may block other optimizations.

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -2468,8 +2468,10 @@ fn add_order_independent_options(
     if sess.target.os == "emscripten" {
         cmd.cc_arg(if sess.panic_strategy() == PanicStrategy::Abort {
             "-sDISABLE_EXCEPTION_CATCHING=1"
-        } else {
+        } else if (sess.unstable_options.emscripten_wasm_eh) {
             "-fwasm-exceptions"
+        } else {
+            "-sDISABLE_EXCEPTION_CATCHING=0"
         });
     }
 

compiler/rustc_codegen_ssa/src/base.rs

@@ -389,6 +389,7 @@ pub(crate) fn build_shift_expr_rhs<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
 // us
 pub fn wants_wasm_eh(sess: &Session) -> bool {
     sess.target.is_like_wasm
+        && (sess.target.os != "emscripten" || sess.unstable_options.emscripten_wasm_eh)
 }
 
 /// Returns `true` if this session's target will use SEH-based unwinding.

compiler/rustc_interface/src/tests.rs

@@ -782,7 +782,7 @@ fn test_unstable_options_tracking_hash() {
     tracked!(dwarf_version, Some(5));
     tracked!(embed_source, true);
     tracked!(emit_thin_lto, false);
-    tracked!(emscripten_wasm_eh)
+    tracked!(emscripten_wasm_eh);
     tracked!(export_executable_symbols, true);
     tracked!(fewer_names, Some(true));
     tracked!(fixed_x18, true);

compiler/rustc_passes/src/weak_lang_items.rs

@@ -26,9 +26,12 @@ pub(crate) fn check_crate(
     if items.eh_personality().is_none() {
         items.missing.push(LangItem::EhPersonality);
     }
-    // if tcx.sess.target.os == "emscripten" && items.eh_catch_typeinfo().is_none() {
-    //     items.missing.push(LangItem::EhCatchTypeinfo);
-    // }
+    if tcx.sess.target.os == "emscripten"
+        && items.eh_catch_typeinfo().is_none()
+        && !tcx.sess.unstable_options.emscripten_wasm_eh
+    {
+        items.missing.push(LangItem::EhCatchTypeinfo);
+    }
 
     visit::Visitor::visit_crate(&mut WeakLangItemVisitor { tcx, items }, krate);