Target modifiers (special marked options) are recorded in metainfo

compiler/rustc_interface/src/passes.rs

@@ -281,6 +281,7 @@ fn configure_and_expand(
 
     resolver.resolve_crate(&krate);
 
+    CStore::from_tcx(tcx).report_incompatible_target_modifiers(tcx, &krate, resolver.lint_buffer());
     krate
 }
 

compiler/rustc_lint/messages.ftl

@@ -415,6 +415,16 @@ lint_improper_ctypes_union_layout_help = consider adding a `#[repr(C)]` or `#[re
 lint_improper_ctypes_union_layout_reason = this union has unspecified layout
 lint_improper_ctypes_union_non_exhaustive = this union is non-exhaustive
 
+lint_incompatible_target_modifiers =
+    mixing `{$flag_name_suffixed}` will cause an ABI mismatch
+    .note1 = `{$flag_name_suffixed}`=`{$flag_local_value}` in crate `{$local_crate}`, `{$flag_name_suffixed}`=`{$flag_extern_value}` in crate `{$extern_crate}`
+    .help = This error occurs because the `{$flag_name_suffixed}` flag modifies the ABI,
+      and different crates in your project were compiled with inconsistent settings
+    .suggestion = To resolve this, ensure that `{$flag_name_suffixed}` is set to the same value
+      for all crates during compilation
+    .note2 = To ignore this error, recompile with the following flag:
+      -Cunsafe-allow-abi-mismatch=`{$flag_name}`
+
 lint_incomplete_include =
     include macro expected single expression in source
 

compiler/rustc_lint/src/context/diagnostics.rs

@@ -422,6 +422,22 @@ pub(super) fn decorate_lint(sess: &Session, diagnostic: BuiltinLintDiag, diag: &
             lints::UnusedCrateDependency { extern_crate, local_crate }.decorate_lint(diag)
         }
         BuiltinLintDiag::WasmCAbi => lints::WasmCAbi.decorate_lint(diag),
+        BuiltinLintDiag::IncompatibleTargetModifiers {
+            extern_crate,
+            local_crate,
+            flag_name,
+            flag_name_suffixed,
+            flag_local_value,
+            flag_extern_value,
+        } => lints::IncompatibleTargetModifiers {
+            extern_crate,
+            local_crate,
+            flag_name,
+            flag_name_suffixed,
+            flag_local_value,
+            flag_extern_value,
+        }
+        .decorate_lint(diag),
         BuiltinLintDiag::IllFormedAttributeInput { suggestions } => {
             lints::IllFormedAttributeInput {
                 num_suggestions: suggestions.len(),

compiler/rustc_lint/src/lints.rs

@@ -2470,6 +2470,20 @@ pub(crate) struct UnusedCrateDependency {
     pub local_crate: Symbol,
 }
 
+#[derive(LintDiagnostic)]
+#[diag(lint_incompatible_target_modifiers)]
+#[help]
+#[note(lint_note1)]
+#[note(lint_note2)]
+pub(crate) struct IncompatibleTargetModifiers {
+    pub extern_crate: Symbol,
+    pub local_crate: Symbol,
+    pub flag_name: String,
+    pub flag_name_suffixed: String,
+    pub flag_local_value: String,
+    pub flag_extern_value: String,
+}
+
 #[derive(LintDiagnostic)]
 #[diag(lint_wasm_c_abi)]
 pub(crate) struct WasmCAbi;

compiler/rustc_lint_defs/src/builtin.rs

@@ -49,6 +49,7 @@ declare_lint_pass! {
         FUZZY_PROVENANCE_CASTS,
         HIDDEN_GLOB_REEXPORTS,
         ILL_FORMED_ATTRIBUTE_INPUT,
+        INCOMPATIBLE_TARGET_MODIFIERS,
         INCOMPLETE_INCLUDE,
         INEFFECTIVE_UNSTABLE_TRAIT_IMPL,
         INLINE_NO_SANITIZE,
@@ -578,6 +579,43 @@ declare_lint! {
     crate_level_only
 }
 
+declare_lint! {
+    /// The `incompatible_target_modifiers` lint detects crates with incompatible target modifiers
+    /// (abi-changing or vulnerability-affecting flags).
+    ///
+    /// ### Example
+    ///
+    /// ```rust,ignore (needs extern crate)
+    /// #![deny(incompatible_target_modifiers)]
+    /// ```
+    ///
+    /// When main and dependency crates are compiled with `-Zregparm=1` and `-Zregparm=2` correspondingly.
+    ///
+    /// This will produce:
+    ///
+    /// ```text
+    /// error: crate `incompatible_regparm` has incompatible target modifier with extern crate `wrong_regparm`: `regparm = ( Some(1) | Some(2) )`
+    /// --> $DIR/incompatible_regparm.rs:5:1
+    ///   |
+    /// 1 | #![no_core]
+    ///   | ^
+    ///   |
+    ///   = note: `#[deny(incompatible_target_modifiers)]` on by default
+    /// ```
+    ///
+    /// ### Explanation
+    ///
+    /// `Target modifiers` are compilation flags that affects abi or vulnerability resistance.
+    /// Linking together crates with incompatible target modifiers would produce incorrect code
+    /// or degradation of vulnerability resistance.
+    /// So this lint should find such inconsistency.
+    ///
+    pub INCOMPATIBLE_TARGET_MODIFIERS,
+    Deny,
+    "Incompatible target modifiers",
+    crate_level_only
+}
+
 declare_lint! {
     /// The `unused_qualifications` lint detects unnecessarily qualified
     /// names.

compiler/rustc_lint_defs/src/lib.rs

@@ -719,6 +719,14 @@ pub enum BuiltinLintDiag {
     AvoidUsingIntelSyntax,
     AvoidUsingAttSyntax,
     IncompleteInclude,
+    IncompatibleTargetModifiers {
+        extern_crate: Symbol,
+        local_crate: Symbol,
+        flag_name: String,
+        flag_name_suffixed: String,
+        flag_local_value: String,
+        flag_extern_value: String,
+    },
     UnnameableTestItems,
     DuplicateMacroAttribute,
     CfgAttrNoAttributes,

compiler/rustc_metadata/src/creader.rs

@@ -24,7 +24,7 @@ use rustc_middle::bug;
 use rustc_middle::ty::{TyCtxt, TyCtxtFeed};
 use rustc_session::config::{self, CrateType, ExternLocation};
 use rustc_session::cstore::{CrateDepKind, CrateSource, ExternCrate, ExternCrateSource};
-use rustc_session::lint::{self, BuiltinLintDiag};
+use rustc_session::lint::{self, BuiltinLintDiag, LintBuffer};
 use rustc_session::output::validate_crate_name;
 use rustc_session::search_paths::PathKind;
 use rustc_span::edition::Edition;
@@ -35,7 +35,9 @@ use tracing::{debug, info, trace};
 
 use crate::errors;
 use crate::locator::{CrateError, CrateLocator, CratePaths};
-use crate::rmeta::{CrateDep, CrateMetadata, CrateNumMap, CrateRoot, MetadataBlob};
+use crate::rmeta::{
+    CrateDep, CrateMetadata, CrateNumMap, CrateRoot, MetadataBlob, TargetModifiers,
+};
 
 /// The backend's way to give the crate store access to the metadata in a library.
 /// Note that it returns the raw metadata bytes stored in the library file, whether
@@ -290,6 +292,94 @@ impl CStore {
         }
     }
 
+    pub fn report_incompatible_target_modifiers(
+        &self,
+        tcx: TyCtxt<'_>,
+        krate: &Crate,
+        lints: &mut LintBuffer,
+    ) {
+        if tcx.crate_types().contains(&CrateType::ProcMacro) {
+            return;
+        }
+        let sess = tcx.sess;
+        if let Some(vec) = &sess.opts.cg.unsafe_allow_abi_mismatch
+            && vec.is_empty()
+        {
+            return;
+        }
+        let span = krate.spans.inner_span.shrink_to_lo();
+
+        let splitter = |v: &String| {
+            let splitted: Vec<_> = v.split("=").collect();
+            (splitted[0].to_string(), splitted[1].to_string())
+        };
+        let name = tcx.crate_name(LOCAL_CRATE);
+        let mods = sess.opts.gather_target_modifiers();
+        for (_cnum, data) in self.iter_crate_data() {
+            if data.is_proc_macro_crate() {
+                continue;
+            }
+            let mut report_diff =
+                |flag_name: &String, flag_local_value: &String, flag_extern_value: &String| {
+                    if let Some(vec) = &sess.opts.cg.unsafe_allow_abi_mismatch {
+                        if vec.contains(flag_name) {
+                            return;
+                        }
+                    }
+                    lints.buffer_lint(
+                        lint::builtin::INCOMPATIBLE_TARGET_MODIFIERS,
+                        ast::CRATE_NODE_ID,
+                        span,
+                        BuiltinLintDiag::IncompatibleTargetModifiers {
+                            extern_crate: data.name(),
+                            local_crate: name,
+                            flag_name: flag_name.to_string(),
+                            flag_name_suffixed: flag_name.to_string(),
+                            flag_local_value: flag_local_value.to_string(),
+                            flag_extern_value: flag_extern_value.to_string(),
+                        },
+                    );
+                };
+            let mut it1 = mods.iter().map(splitter);
+            let mut it2 = data.target_modifiers().map(splitter);
+            let mut left_name_val: Option<(String, String)> = None;
+            let mut right_name_val: Option<(String, String)> = None;
+            let no_val = "*".to_string();
+            loop {
+                left_name_val = left_name_val.or_else(|| it1.next());
+                right_name_val = right_name_val.or_else(|| it2.next());
+                match (&left_name_val, &right_name_val) {
+                    (Some(l), Some(r)) => match l.0.cmp(&r.0) {
+                        cmp::Ordering::Equal => {
+                            if l.1 != r.1 {
+                                report_diff(&l.0, &l.1, &r.1);
+                            }
+                            left_name_val = None;
+                            right_name_val = None;
+                        }
+                        cmp::Ordering::Greater => {
+                            report_diff(&r.0, &no_val, &r.1);
+                            right_name_val = None;
+                        }
+                        cmp::Ordering::Less => {
+                            report_diff(&l.0, &l.1, &no_val);
+                            left_name_val = None;
+                        }
+                    },
+                    (Some(l), None) => {
+                        report_diff(&l.0, &l.1, &no_val);
+                        left_name_val = None;
+                    }
+                    (None, Some(r)) => {
+                        report_diff(&r.0, &no_val, &r.1);
+                        right_name_val = None;
+                    }
+                    (None, None) => break,
+                }
+            }
+        }
+    }
+
     pub fn new(metadata_loader: Box<MetadataLoaderDyn>) -> CStore {
         CStore {
             metadata_loader,
@@ -432,6 +522,7 @@ impl<'a, 'tcx> CrateLoader<'a, 'tcx> {
         };
 
         let cnum_map = self.resolve_crate_deps(root, &crate_root, &metadata, cnum, dep_kind)?;
+        let target_modifiers = self.resolve_target_modifiers(&crate_root, &metadata, cnum)?;
 
         let raw_proc_macros = if crate_root.is_proc_macro_crate() {
             let temp_root;
@@ -456,6 +547,7 @@ impl<'a, 'tcx> CrateLoader<'a, 'tcx> {
             raw_proc_macros,
             cnum,
             cnum_map,
+            target_modifiers,
             dep_kind,
             source,
             private_dep,
@@ -689,6 +781,25 @@ impl<'a, 'tcx> CrateLoader<'a, 'tcx> {
         Ok(crate_num_map)
     }
 
+    fn resolve_target_modifiers(
+        &mut self,
+        crate_root: &CrateRoot,
+        metadata: &MetadataBlob,
+        krate: CrateNum,
+    ) -> Result<TargetModifiers, CrateError> {
+        debug!("resolving target modifiers of external crate");
+        if crate_root.is_proc_macro_crate() {
+            return Ok(TargetModifiers::new());
+        }
+        let mods = crate_root.decode_target_modifiers(metadata);
+        let mut target_modifiers = TargetModifiers::with_capacity(mods.len());
+        for modifier in mods {
+            target_modifiers.push(modifier);
+        }
+        debug!("resolve_target_modifiers: target mods for {:?} is {:?}", krate, target_modifiers);
+        Ok(target_modifiers)
+    }
+
     fn dlsym_proc_macros(
         &self,
         path: &Path,

compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -73,6 +73,9 @@ impl MetadataBlob {
 /// own crate numbers.
 pub(crate) type CrateNumMap = IndexVec<CrateNum, CrateNum>;
 
+/// Target modifiers - abi / vulnerability-resist affecting flags
+pub(crate) type TargetModifiers = Vec<String>;
+
 pub(crate) struct CrateMetadata {
     /// The primary crate data - binary metadata blob.
     blob: MetadataBlob,
@@ -110,6 +113,8 @@ pub(crate) struct CrateMetadata {
     cnum_map: CrateNumMap,
     /// Same ID set as `cnum_map` plus maybe some injected crates like panic runtime.
     dependencies: Vec<CrateNum>,
+    /// Target modifiers - abi and vulnerability-resist affecting flags the crate was compiled with
+    target_modifiers: TargetModifiers,
     /// How to link (or not link) this crate to the currently compiled crate.
     dep_kind: CrateDepKind,
     /// Filesystem location of this crate.
@@ -960,6 +965,13 @@ impl CrateRoot {
     ) -> impl ExactSizeIterator<Item = CrateDep> + Captures<'a> {
         self.crate_deps.decode(metadata)
     }
+
+    pub(crate) fn decode_target_modifiers<'a>(
+        &self,
+        metadata: &'a MetadataBlob,
+    ) -> impl ExactSizeIterator<Item = String> + Captures<'a> {
+        self.target_modifiers.decode(metadata)
+    }
 }
 
 impl<'a> CrateMetadataRef<'a> {
@@ -1815,6 +1827,7 @@ impl CrateMetadata {
         raw_proc_macros: Option<&'static [ProcMacro]>,
         cnum: CrateNum,
         cnum_map: CrateNumMap,
+        target_modifiers: TargetModifiers,
         dep_kind: CrateDepKind,
         source: CrateSource,
         private_dep: bool,
@@ -1846,6 +1859,7 @@ impl CrateMetadata {
             cnum,
             cnum_map,
             dependencies,
+            target_modifiers,
             dep_kind,
             source: Lrc::new(source),
             private_dep,
@@ -1875,6 +1889,10 @@ impl CrateMetadata {
         self.dependencies.push(cnum);
     }
 
+    pub(crate) fn target_modifiers(&self) -> impl Iterator<Item = &String> + '_ {
+        self.target_modifiers.iter()
+    }
+
     pub(crate) fn update_extern_crate(&mut self, new_extern_crate: ExternCrate) -> bool {
         let update =
             Some(new_extern_crate.rank()) > self.extern_crate.as_ref().map(ExternCrate::rank);

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -692,6 +692,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         // Encode source_map. This needs to be done last, because encoding `Span`s tells us which
         // `SourceFiles` we actually need to encode.
         let source_map = stat!("source-map", || self.encode_source_map());
+        let target_modifiers = stat!("target-modifiers", || self.encode_target_modifiers());
 
         let root = stat!("final", || {
             let attrs = tcx.hir().krate_attrs();
@@ -732,6 +733,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                 native_libraries,
                 foreign_modules,
                 source_map,
+                target_modifiers,
                 traits,
                 impls,
                 incoherent_impls,
@@ -1978,6 +1980,12 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         self.lazy_array(deps.iter().map(|(_, dep)| dep))
     }
 
+    fn encode_target_modifiers(&mut self) -> LazyArray<String> {
+        empty_proc_macro!(self);
+        let tcx = self.tcx;
+        self.lazy_array(tcx.sess.opts.gather_target_modifiers())
+    }
+
     fn encode_lib_features(&mut self) -> LazyArray<(Symbol, FeatureStability)> {
         empty_proc_macro!(self);
         let tcx = self.tcx;

compiler/rustc_metadata/src/rmeta/mod.rs

@@ -1,7 +1,7 @@
 use std::marker::PhantomData;
 use std::num::NonZero;
 
-pub(crate) use decoder::{CrateMetadata, CrateNumMap, MetadataBlob};
+pub(crate) use decoder::{CrateMetadata, CrateNumMap, MetadataBlob, TargetModifiers};
 use decoder::{DecodeContext, Metadata};
 use def_path_hash_map::DefPathHashMapRef;
 use encoder::EncodeContext;
@@ -283,6 +283,7 @@ pub(crate) struct CrateRoot {
     def_path_hash_map: LazyValue<DefPathHashMapRef<'static>>,
 
     source_map: LazyTable<u32, Option<LazyValue<rustc_span::SourceFile>>>,
+    target_modifiers: LazyArray<String>,
 
     compiler_builtins: bool,
     needs_allocator: bool,