Auto merge of #113162 - matthiaskrgr:rollup-fct3wj7, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - #111322 (Support for native WASM exceptions)
 - #112086 (resolve: Remove artificial import ambiguity errors)
 - #112234 (refactor `tool_doc!`)
 - #112300 (Convert `run-make/coverage-reports` tests to use a custom compiletest mode)
 - #112795 (Migrate some rustc_builtin_macros to SessionDiagnostic)
 - #113144 (Make the `Elaboratable` trait take clauses)
 - #113161 (Fix type privacy lints error message)

r? `@ghost`
`@rustbot` modify labels: rollup

4 files changed, 38 insertions, 6 deletions

diff --git a/compiler/rustc_codegen_ssa/src/base.rs b/compiler/rustc_codegen_ssa/src/base.rs
index 28f3c23364c..f8ced6949d5 100644
--- a/compiler/rustc_codegen_ssa/src/base.rs
+++ b/compiler/rustc_codegen_ssa/src/base.rs
@@ -357,6 +357,13 @@ pub fn cast_shift_expr_rhs<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
     }
 }
 
+// Returns `true` if this session's target will use native wasm
+// exceptions. This means that the VM does the unwinding for
+// us
+pub fn wants_wasm_eh(sess: &Session) -> bool {
+    sess.target.is_like_wasm && sess.target.os != "emscripten"
+}
+
 /// Returns `true` if this session's target will use SEH-based unwinding.
 ///
 /// This is only true for MSVC targets, and even then the 64-bit MSVC target
@@ -366,6 +373,13 @@ pub fn wants_msvc_seh(sess: &Session) -> bool {
     sess.target.is_like_msvc
 }
 
+/// Returns `true` if this session's target requires the new exception
+/// handling LLVM IR instructions (catchpad / cleanuppad / ... instead
+/// of landingpad)
+pub fn wants_new_eh_instructions(sess: &Session) -> bool {
+    wants_wasm_eh(sess) || wants_msvc_seh(sess)
+}
+
 pub fn memcpy_ty<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
     bx: &mut Bx,
     dst: Bx::Value,
diff --git a/compiler/rustc_codegen_ssa/src/mir/block.rs b/compiler/rustc_codegen_ssa/src/mir/block.rs
index 5e40b672866..ac566c49ed4 100644
--- a/compiler/rustc_codegen_ssa/src/mir/block.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/block.rs
@@ -79,8 +79,8 @@ impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> {
             lltarget = fx.landing_pad_for(target);
         }
         if is_cleanupret {
-            // MSVC cross-funclet jump - need a trampoline
-            debug_assert!(base::wants_msvc_seh(fx.cx.tcx().sess));
+            // Cross-funclet jump - need a trampoline
+            debug_assert!(base::wants_new_eh_instructions(fx.cx.tcx().sess));
             debug!("llbb_with_cleanup: creating cleanup trampoline for {:?}", target);
             let name = &format!("{:?}_cleanup_trampoline_{:?}", self.bb, target);
             let trampoline_llbb = Bx::append_block(fx.cx, fx.llfn, name);
@@ -177,9 +177,16 @@ impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> {
             mir::UnwindAction::Continue => None,
             mir::UnwindAction::Unreachable => None,
             mir::UnwindAction::Terminate => {
-                if fx.mir[self.bb].is_cleanup && base::wants_msvc_seh(fx.cx.tcx().sess) {
-                    // SEH will abort automatically if an exception tries to
+                if fx.mir[self.bb].is_cleanup && base::wants_new_eh_instructions(fx.cx.tcx().sess) {
+                    // MSVC SEH will abort automatically if an exception tries to
                     // propagate out from cleanup.
+
+                    // FIXME(@mirkootter): For wasm, we currently do not support terminate during
+                    // cleanup, because this requires a few more changes: The current code
+                    // caches the `terminate_block` for each function; funclet based code - however -
+                    // requires a different terminate_block for each funclet
+                    // Until this is implemented, we just do not unwind inside cleanup blocks
+
                     None
                 } else {
                     Some(fx.terminate_block())
@@ -1528,7 +1535,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     // FIXME(eddyb) rename this to `eh_pad_for_uncached`.
     fn landing_pad_for_uncached(&mut self, bb: mir::BasicBlock) -> Bx::BasicBlock {
         let llbb = self.llbb(bb);
-        if base::wants_msvc_seh(self.cx.sess()) {
+        if base::wants_new_eh_instructions(self.cx.sess()) {
             let cleanup_bb = Bx::append_block(self.cx, self.llfn, &format!("funclet_{:?}", bb));
             let mut cleanup_bx = Bx::build(self.cx, cleanup_bb);
             let funclet = cleanup_bx.cleanup_pad(None, &[]);
@@ -1587,6 +1594,15 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 //      } catch (...) {
                 //          bar();
                 //      }
+                //
+                // which creates an IR snippet like
+                //
+                //      cs_terminate:
+                //         %cs = catchswitch within none [%cp_terminate] unwind to caller
+                //      cp_terminate:
+                //         %cp = catchpad within %cs [null, i32 64, null]
+                //         ...
+
                 llbb = Bx::append_block(self.cx, self.llfn, "cs_terminate");
                 let cp_llbb = Bx::append_block(self.cx, self.llfn, "cp_terminate");
 
diff --git a/compiler/rustc_codegen_ssa/src/mir/mod.rs b/compiler/rustc_codegen_ssa/src/mir/mod.rs
index 15b0e34b8e4..9ff6a249748 100644
--- a/compiler/rustc_codegen_ssa/src/mir/mod.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/mod.rs
@@ -179,7 +179,8 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
         start_bx.set_personality_fn(cx.eh_personality());
     }
 
-    let cleanup_kinds = base::wants_msvc_seh(cx.tcx().sess).then(|| analyze::cleanup_kinds(&mir));
+    let cleanup_kinds =
+        base::wants_new_eh_instructions(cx.tcx().sess).then(|| analyze::cleanup_kinds(&mir));
 
     let cached_llbbs: IndexVec<mir::BasicBlock, CachedLlbb<Bx::BasicBlock>> =
         mir.basic_blocks
diff --git a/compiler/rustc_codegen_ssa/src/target_features.rs b/compiler/rustc_codegen_ssa/src/target_features.rs
index 6a3a31a0d60..9e06fec550d 100644
--- a/compiler/rustc_codegen_ssa/src/target_features.rs
+++ b/compiler/rustc_codegen_ssa/src/target_features.rs
@@ -284,6 +284,7 @@ const WASM_ALLOWED_FEATURES: &[(&str, Option<Symbol>)] = &[
     // tidy-alphabetical-start
     ("atomics", Some(sym::wasm_target_feature)),
     ("bulk-memory", Some(sym::wasm_target_feature)),
+    ("exception-handling", Some(sym::wasm_target_feature)),
     ("multivalue", Some(sym::wasm_target_feature)),
     ("mutable-globals", Some(sym::wasm_target_feature)),
     ("nontrapping-fptoint", Some(sym::wasm_target_feature)),