diff options
Diffstat (limited to 'compiler/rustc_mir_transform/src')
| -rw-r--r-- | compiler/rustc_mir_transform/src/check_inline_always_target_features.rs | 88 | ||||
| -rw-r--r-- | compiler/rustc_mir_transform/src/errors.rs | 41 | ||||
| -rw-r--r-- | compiler/rustc_mir_transform/src/lib.rs | 4 |
3 files changed, 133 insertions, 0 deletions
diff --git a/compiler/rustc_mir_transform/src/check_inline_always_target_features.rs b/compiler/rustc_mir_transform/src/check_inline_always_target_features.rs new file mode 100644 index 00000000000..abad28f0a8f --- /dev/null +++ b/compiler/rustc_mir_transform/src/check_inline_always_target_features.rs @@ -0,0 +1,88 @@ +use rustc_hir::attrs::InlineAttr; +use rustc_middle::middle::codegen_fn_attrs::{TargetFeature, TargetFeatureKind}; +use rustc_middle::mir::{Body, TerminatorKind}; +use rustc_middle::ty::{self, TyCtxt}; + +use crate::pass_manager::MirLint; + +pub(super) struct CheckInlineAlwaysTargetFeature; + +impl<'tcx> MirLint<'tcx> for CheckInlineAlwaysTargetFeature { + fn run_lint(&self, tcx: TyCtxt<'tcx>, body: &Body<'tcx>) { + check_inline_always_target_features(tcx, body) + } +} + +/// `#[target_feature]`-annotated functions can be marked `#[inline]` and will only be inlined if +/// the target features match (as well as all of the other inlining heuristics). `#[inline(always)]` +/// will always inline regardless of matching target features, which can result in errors from LLVM. +/// However, it is desirable to be able to always annotate certain functions (e.g. SIMD intrinsics) +/// as `#[inline(always)]` but check the target features match in Rust to avoid the LLVM errors. +/// +/// We check the caller and callee target features to ensure that this can +/// be done or emit a lint. +#[inline] +fn check_inline_always_target_features<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>) { + let caller_def_id = body.source.def_id().expect_local(); + if !tcx.def_kind(caller_def_id).has_codegen_attrs() { + return; + } + + let caller_codegen_fn_attrs = tcx.codegen_fn_attrs(caller_def_id); + + for bb in body.basic_blocks.iter() { + let terminator = bb.terminator(); + match &terminator.kind { + TerminatorKind::Call { func, .. } | TerminatorKind::TailCall { func, .. } => { + let fn_ty = func.ty(body, tcx); + let ty::FnDef(callee_def_id, _) = *fn_ty.kind() else { + continue; + }; + + if !tcx.def_kind(callee_def_id).has_codegen_attrs() { + continue; + } + let callee_codegen_fn_attrs = tcx.codegen_fn_attrs(callee_def_id); + if callee_codegen_fn_attrs.inline != InlineAttr::Always + || callee_codegen_fn_attrs.target_features.is_empty() + { + continue; + } + + // Scan the users defined target features and ensure they + // match the caller. + if tcx.is_target_feature_call_safe( + &callee_codegen_fn_attrs.target_features, + &caller_codegen_fn_attrs + .target_features + .iter() + .cloned() + .chain(tcx.sess.target_features.iter().map(|feat| TargetFeature { + name: *feat, + kind: TargetFeatureKind::Implied, + })) + .collect::<Vec<_>>(), + ) { + continue; + } + + let callee_only: Vec<_> = callee_codegen_fn_attrs + .target_features + .iter() + .filter(|it| !caller_codegen_fn_attrs.target_features.contains(it)) + .filter(|it| !matches!(it.kind, TargetFeatureKind::Implied)) + .map(|it| it.name.as_str()) + .collect(); + + crate::errors::emit_inline_always_target_feature_diagnostic( + tcx, + terminator.source_info.span, + callee_def_id, + caller_def_id.into(), + &callee_only, + ); + } + _ => (), + } + } +} diff --git a/compiler/rustc_mir_transform/src/errors.rs b/compiler/rustc_mir_transform/src/errors.rs index ad9635aae33..775f5f9a7cf 100644 --- a/compiler/rustc_mir_transform/src/errors.rs +++ b/compiler/rustc_mir_transform/src/errors.rs @@ -2,6 +2,7 @@ use rustc_errors::codes::*; use rustc_errors::{Diag, LintDiagnostic}; use rustc_macros::{Diagnostic, LintDiagnostic, Subdiagnostic}; use rustc_middle::mir::AssertKind; +use rustc_middle::query::Key; use rustc_middle::ty::TyCtxt; use rustc_session::lint::{self, Lint}; use rustc_span::def_id::DefId; @@ -9,6 +10,46 @@ use rustc_span::{Ident, Span, Symbol}; use crate::fluent_generated as fluent; +/// Emit diagnostic for calls to `#[inline(always)]`-annotated functions with a +/// `#[target_feature]` attribute where the caller enables a different set of target features. +pub(crate) fn emit_inline_always_target_feature_diagnostic<'a, 'tcx>( + tcx: TyCtxt<'tcx>, + call_span: Span, + callee_def_id: DefId, + caller_def_id: DefId, + callee_only: &[&'a str], +) { + let callee = tcx.def_path_str(callee_def_id); + let caller = tcx.def_path_str(caller_def_id); + + tcx.node_span_lint( + lint::builtin::INLINE_ALWAYS_MISMATCHING_TARGET_FEATURES, + tcx.local_def_id_to_hir_id(caller_def_id.as_local().unwrap()), + call_span, + |lint| { + lint.primary_message(format!( + "call to `#[inline(always)]`-annotated `{callee}` \ + requires the same target features to be inlined" + )); + lint.note("function will not be inlined"); + + lint.note(format!( + "the following target features are on `{callee}` but missing from `{caller}`: {}", + callee_only.join(", ") + )); + lint.span_note(callee_def_id.default_span(tcx), format!("`{callee}` is defined here")); + + let feats = callee_only.join(","); + lint.span_suggestion( + tcx.def_span(caller_def_id).shrink_to_lo(), + format!("add `#[target_feature]` attribute to `{caller}`"), + format!("#[target_feature(enable = \"{feats}\")]\n"), + lint::Applicability::MaybeIncorrect, + ); + }, + ); +} + #[derive(LintDiagnostic)] #[diag(mir_transform_unconditional_recursion)] #[help] diff --git a/compiler/rustc_mir_transform/src/lib.rs b/compiler/rustc_mir_transform/src/lib.rs index 8f319e64916..1663dfa744f 100644 --- a/compiler/rustc_mir_transform/src/lib.rs +++ b/compiler/rustc_mir_transform/src/lib.rs @@ -117,6 +117,7 @@ declare_passes! { mod add_subtyping_projections : Subtyper; mod check_inline : CheckForceInline; mod check_call_recursion : CheckCallRecursion, CheckDropRecursion; + mod check_inline_always_target_features: CheckInlineAlwaysTargetFeature; mod check_alignment : CheckAlignment; mod check_enums : CheckEnums; mod check_const_item_mutation : CheckConstItemMutation; @@ -384,6 +385,9 @@ fn mir_built(tcx: TyCtxt<'_>, def: LocalDefId) -> &Steal<Body<'_>> { // MIR-level lints. &Lint(check_inline::CheckForceInline), &Lint(check_call_recursion::CheckCallRecursion), + // Check callee's target features match callers target features when + // using `#[inline(always)]` + &Lint(check_inline_always_target_features::CheckInlineAlwaysTargetFeature), &Lint(check_packed_ref::CheckPackedRef), &Lint(check_const_item_mutation::CheckConstItemMutation), &Lint(function_item_references::FunctionItemReferences), |