Use Spans to detect "system crate"s, for error deferral (zombie) purposes.

crates/rustc_codegen_spirv/src/builder/builder_methods.rs

@@ -1469,7 +1469,7 @@ impl<'a, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'tcx> {
                 .with_type(dest_ty);
 
             if val_is_ptr || dest_is_ptr {
-                if self.is_system_crate() {
+                if self.is_system_crate(self.span()) {
                     self.zombie(
                         result.def(self),
                         &format!(

crates/rustc_codegen_spirv/src/builder_spirv.rs

@@ -149,7 +149,7 @@ impl SpirvValue {
             }
 
             SpirvValueKind::FnAddr { .. } => {
-                if cx.is_system_crate() {
+                if cx.is_system_crate(span) {
                     cx.builder
                         .const_to_id
                         .borrow()
@@ -160,9 +160,10 @@ impl SpirvValue {
                         .expect("FnAddr didn't go through proper undef registration")
                         .val
                 } else {
-                    cx.tcx
-                        .sess
-                        .err("Cannot use this function pointer for anything other than calls");
+                    cx.tcx.sess.span_err(
+                        span,
+                        "Cannot use this function pointer for anything other than calls",
+                    );
                     // Because we never get beyond compilation (into e.g. linking),
                     // emitting an invalid ID reference here is OK.
                     0
@@ -174,7 +175,7 @@ impl SpirvValue {
                 original_pointee_ty,
                 zombie_target_undef,
             } => {
-                if cx.is_system_crate() {
+                if cx.is_system_crate(span) {
                     cx.zombie_with_span(
                         zombie_target_undef,
                         span,

crates/rustc_codegen_spirv/src/codegen_cx/mod.rs

@@ -24,7 +24,7 @@ use rustc_middle::mir::Body;
 use rustc_middle::ty::layout::{HasParamEnv, HasTyCtxt};
 use rustc_middle::ty::{Instance, ParamEnv, PolyExistentialTraitRef, Ty, TyCtxt};
 use rustc_session::Session;
-use rustc_span::def_id::{DefId, LOCAL_CRATE};
+use rustc_span::def_id::DefId;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::{SourceFile, Span, DUMMY_SP};
 use rustc_target::abi::call::{FnAbi, PassMode};
@@ -166,7 +166,7 @@ impl<'tcx> CodegenCx<'tcx> {
     /// Finally, if *user* code is marked as zombie, then this means that the user tried to do
     /// something that isn't supported, and should be an error.
     pub fn zombie_with_span(&self, word: Word, span: Span, reason: &str) {
-        if self.is_system_crate() {
+        if self.is_system_crate(span) {
             self.zombie_even_in_user_code(word, span, reason);
         } else {
             self.tcx.sess.span_err(span, reason);
@@ -185,14 +185,30 @@ impl<'tcx> CodegenCx<'tcx> {
         );
     }
 
-    pub fn is_system_crate(&self) -> bool {
-        self.tcx
+    /// Returns `true` if the originating crate of `span` (which could very well
+    /// be a different crate, e.g. a generic/`#[inline]` function, or a macro),
+    /// is a "system crate", and therefore allowed to have some errors deferred
+    /// as "zombies" (see `zombie_with_span`'s docs above for more details).
+    pub fn is_system_crate(&self, span: Span) -> bool {
+        // HACK(eddyb) this ignores `.lo` vs `.hi` potentially resulting in
+        // different `SourceFile`s (which is likely a bug anyway).
+        let cnum = self
+            .tcx
             .sess
-            .contains_name(self.tcx.hir().krate_attrs(), sym::compiler_builtins)
-            || self.tcx.crate_name(LOCAL_CRATE) == sym::core
-            || self.tcx.crate_name(LOCAL_CRATE) == self.sym.spirv_std
-            || self.tcx.crate_name(LOCAL_CRATE) == self.sym.libm
-            || self.tcx.crate_name(LOCAL_CRATE) == self.sym.num_traits
+            .source_map()
+            .lookup_source_file(span.data().lo)
+            .cnum;
+
+        self.tcx
+            .get_attr(cnum.as_def_id(), sym::compiler_builtins)
+            .is_some()
+            || [
+                sym::core,
+                self.sym.spirv_std,
+                self.sym.libm,
+                self.sym.num_traits,
+            ]
+            .contains(&self.tcx.crate_name(cnum))
     }
 
     pub fn finalize_module(self) -> Module {
@@ -532,7 +548,7 @@ impl<'tcx> MiscMethods<'tcx> for CodegenCx<'tcx> {
         }
         .def(span, self);
 
-        if self.is_system_crate() {
+        if self.is_system_crate(span) {
             // Create these undefs up front instead of on demand in SpirvValue::def because
             // SpirvValue::def can't use cx.emit()
             self.def_constant(ty, SpirvConst::ZombieUndefForFnAddr);

tests/ui/dis/ptr_copy.normal.stderr

@@ -3,6 +3,12 @@ error: Cannot memcpy dynamically sized data
      |
 2431 |         copy(src, dst, count)
      |         ^^^^^^^^^^^^^^^^^^^^^
+     |
+     = note: Stack:
+             core::intrinsics::copy::<f32>
+             ptr_copy::copy_via_raw_ptr
+             ptr_copy::main
+             main
 
 error: aborting due to previous error