Auto merge of rust-lang#138747 - matthiaskrgr:rollup-68x44rw, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - rust-lang#138435 (Add support for postfix yield expressions)
 - rust-lang#138685 (Use `Option<Ident>` for lowered param names.)
 - rust-lang#138700 (Suggest `-Whelp` when pass `--print lints` to rustc)
 - rust-lang#138727 (Do not rely on `type_var_origin` in `OrphanCheckErr::NonLocalInputType`)
 - rust-lang#138729 (Clean up `FnCtxt::resolve_coroutine_interiors`)
 - rust-lang#138731 (coverage: Add LLVM plumbing for expansion regions)
 - rust-lang#138732 (Use `def_path_str` for def id arg in `UnsupportedOpInfo`)
 - rust-lang#138735 (Remove `llvm` and `llvms` triagebot ping aliases for `icebreakers-llvm` ping group)

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

Author: bors

compiler/rustc_codegen_llvm/src/coverageinfo/llvm_cov.rs

@@ -63,8 +63,18 @@ pub(crate) fn write_function_mappings_to_buffer(
     expressions: &[ffi::CounterExpression],
     regions: &ffi::Regions,
 ) -> Vec<u8> {
-    let ffi::Regions { code_regions, branch_regions, mcdc_branch_regions, mcdc_decision_regions } =
-        regions;
+    let ffi::Regions {
+        code_regions,
+        expansion_regions,
+        branch_regions,
+        mcdc_branch_regions,
+        mcdc_decision_regions,
+    } = regions;
+
+    // SAFETY:
+    // - All types are FFI-compatible and have matching representations in Rust/C++.
+    // - For pointer/length pairs, the pointer and length come from the same vector or slice.
+    // - C++ code does not retain any pointers after the call returns.
     llvm::build_byte_buffer(|buffer| unsafe {
         llvm::LLVMRustCoverageWriteFunctionMappingsToBuffer(
             virtual_file_mapping.as_ptr(),
@@ -73,6 +83,8 @@ pub(crate) fn write_function_mappings_to_buffer(
             expressions.len(),
             code_regions.as_ptr(),
             code_regions.len(),
+            expansion_regions.as_ptr(),
+            expansion_regions.len(),
             branch_regions.as_ptr(),
             branch_regions.len(),
             mcdc_branch_regions.as_ptr(),

compiler/rustc_codegen_llvm/src/coverageinfo/mapgen/covfun.rs

@@ -120,12 +120,22 @@ fn fill_region_tables<'tcx>(
     // Associate that global file ID with a local file ID for this function.
     let local_file_id = covfun.virtual_file_mapping.local_id_for_global(global_file_id);
 
-    let ffi::Regions { code_regions, branch_regions, mcdc_branch_regions, mcdc_decision_regions } =
-        &mut covfun.regions;
-
-    let make_cov_span =
-        |span: Span| spans::make_coverage_span(local_file_id, source_map, &source_file, span);
+    // In rare cases, _all_ of a function's spans are discarded, and coverage
+    // codegen needs to handle that gracefully to avoid #133606.
+    // It's hard for tests to trigger this organically, so instead we set
+    // `-Zcoverage-options=discard-all-spans-in-codegen` to force it to occur.
     let discard_all = tcx.sess.coverage_discard_all_spans_in_codegen();
+    let make_coords = |span: Span| {
+        if discard_all { None } else { spans::make_coords(source_map, &source_file, span) }
+    };
+
+    let ffi::Regions {
+        code_regions,
+        expansion_regions: _, // FIXME(Zalathar): Fill out support for expansion regions
+        branch_regions,
+        mcdc_branch_regions,
+        mcdc_decision_regions,
+    } = &mut covfun.regions;
 
     // For each counter/region pair in this function+file, convert it to a
     // form suitable for FFI.
@@ -140,17 +150,8 @@ fn fill_region_tables<'tcx>(
             ffi::Counter::from_term(term)
         };
 
-        // Convert the `Span` into coordinates that we can pass to LLVM, or
-        // discard the span if conversion fails. In rare, cases _all_ of a
-        // function's spans are discarded, and the rest of coverage codegen
-        // needs to handle that gracefully to avoid a repeat of #133606.
-        // We don't have a good test case for triggering that organically, so
-        // instead we set `-Zcoverage-options=discard-all-spans-in-codegen`
-        // to force it to occur.
-        let Some(cov_span) = make_cov_span(span) else { continue };
-        if discard_all {
-            continue;
-        }
+        let Some(coords) = make_coords(span) else { continue };
+        let cov_span = coords.make_coverage_span(local_file_id);
 
         match *kind {
             MappingKind::Code { bcb } => {