share the track_caller handling within a mir::Body

Author: RalfJung

compiler/rustc_codegen_cranelift/src/common.rs

@@ -430,38 +430,11 @@ impl<'tcx> FunctionCx<'_, '_, 'tcx> {
         }
     }
 
-    // Note: must be kept in sync with get_caller_location from cg_ssa
-    pub(crate) fn get_caller_location(&mut self, mut source_info: mir::SourceInfo) -> CValue<'tcx> {
-        let span_to_caller_location = |fx: &mut FunctionCx<'_, '_, 'tcx>, span: Span| {
-            let const_loc = fx.tcx.span_as_caller_location(span);
-            crate::constant::codegen_const_value(fx, const_loc, fx.tcx.caller_location_ty())
-        };
-
-        // Walk up the `SourceScope`s, in case some of them are from MIR inlining.
-        // If so, the starting `source_info.span` is in the innermost inlined
-        // function, and will be replaced with outer callsite spans as long
-        // as the inlined functions were `#[track_caller]`.
-        loop {
-            let scope_data = &self.mir.source_scopes[source_info.scope];
-
-            if let Some((callee, callsite_span)) = scope_data.inlined {
-                // Stop inside the most nested non-`#[track_caller]` function,
-                // before ever reaching its caller (which is irrelevant).
-                if !callee.def.requires_caller_location(self.tcx) {
-                    return span_to_caller_location(self, source_info.span);
-                }
-                source_info.span = callsite_span;
-            }
-
-            // Skip past all of the parents with `inlined: None`.
-            match scope_data.inlined_parent_scope {
-                Some(parent) => source_info.scope = parent,
-                None => break,
-            }
-        }
-
-        // No inlined `SourceScope`s, or all of them were `#[track_caller]`.
-        self.caller_location.unwrap_or_else(|| span_to_caller_location(self, source_info.span))
+    pub(crate) fn get_caller_location(&mut self, source_info: mir::SourceInfo) -> CValue<'tcx> {
+        self.mir.caller_location_span(source_info, self.caller_location, self.tcx, |span| {
+            let const_loc = self.tcx.span_as_caller_location(span);
+            crate::constant::codegen_const_value(self, const_loc, self.tcx.caller_location_ty())
+        })
     }
 
     pub(crate) fn anonymous_str(&mut self, msg: &str) -> Value {

compiler/rustc_codegen_ssa/src/mir/block.rs

@@ -1449,40 +1449,12 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     fn get_caller_location(
         &mut self,
         bx: &mut Bx,
-        mut source_info: mir::SourceInfo,
+        source_info: mir::SourceInfo,
     ) -> OperandRef<'tcx, Bx::Value> {
-        let tcx = bx.tcx();
-
-        let mut span_to_caller_location = |span: Span| {
-            let const_loc = tcx.span_as_caller_location(span);
+        self.mir.caller_location_span(source_info, self.caller_location, bx.tcx(), |span: Span| {
+            let const_loc = bx.tcx().span_as_caller_location(span);
             OperandRef::from_const(bx, const_loc, bx.tcx().caller_location_ty())
-        };
-
-        // Walk up the `SourceScope`s, in case some of them are from MIR inlining.
-        // If so, the starting `source_info.span` is in the innermost inlined
-        // function, and will be replaced with outer callsite spans as long
-        // as the inlined functions were `#[track_caller]`.
-        loop {
-            let scope_data = &self.mir.source_scopes[source_info.scope];
-
-            if let Some((callee, callsite_span)) = scope_data.inlined {
-                // Stop inside the most nested non-`#[track_caller]` function,
-                // before ever reaching its caller (which is irrelevant).
-                if !callee.def.requires_caller_location(tcx) {
-                    return span_to_caller_location(source_info.span);
-                }
-                source_info.span = callsite_span;
-            }
-
-            // Skip past all of the parents with `inlined: None`.
-            match scope_data.inlined_parent_scope {
-                Some(parent) => source_info.scope = parent,
-                None => break,
-            }
-        }
-
-        // No inlined `SourceScope`s, or all of them were `#[track_caller]`.
-        self.caller_location.unwrap_or_else(|| span_to_caller_location(source_info.span))
+        })
     }
 
     fn get_personality_slot(&mut self, bx: &mut Bx) -> PlaceRef<'tcx, Bx::Value> {

compiler/rustc_const_eval/src/interpret/eval_context.rs

@@ -622,35 +622,17 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 }
             }
 
-            // Note: this must be kept in sync with get_caller_location from cg_ssa.
-
-            // Walk up the `SourceScope`s, in case some of them are from MIR inlining.
-            // If so, the starting `source_info.span` is in the innermost inlined
-            // function, and will be replaced with outer callsite spans as long
-            // as the inlined functions were `#[track_caller]`.
-            loop {
-                let scope_data = &frame.body.source_scopes[source_info.scope];
-
-                if let Some((callee, callsite_span)) = scope_data.inlined {
-                    // Stop inside the most nested non-`#[track_caller]` function,
-                    // before ever reaching its caller (which is irrelevant).
-                    if !callee.def.requires_caller_location(*self.tcx) {
-                        return source_info.span;
-                    }
-                    source_info.span = callsite_span;
-                }
-
-                // Skip past all of the parents with `inlined: None`.
-                match scope_data.inlined_parent_scope {
-                    Some(parent) => source_info.scope = parent,
-                    None => break,
-                }
-            }
-
-            // Stop inside the most nested non-`#[track_caller]` function,
-            // before ever reaching its caller (which is irrelevant).
-            if !frame.instance.def.requires_caller_location(*self.tcx) {
-                return source_info.span;
+            let caller_location = if frame.instance.def.requires_caller_location(*self.tcx) {
+                // We use `Err(())` as indication that we should continue up the call stack since
+                // this is a `#[track_caller]` function.
+                Some(Err(()))
+            } else {
+                None
+            };
+            if let Ok(span) =
+                frame.body.caller_location_span(source_info, caller_location, *self.tcx, Ok)
+            {
+                return span;
             }
         }
 

compiler/rustc_middle/src/mir/mod.rs

@@ -578,6 +578,40 @@ impl<'tcx> Body<'tcx> {
     pub fn is_custom_mir(&self) -> bool {
         self.injection_phase.is_some()
     }
+
+    /// For a `Location` in this scope, determine what the "caller location" at that point is. This
+    /// is interesting because of inlining: the `#[track_caller]` attribute of inlined functions
+    /// must be honored. Falls back to the `tracked_caller` value for `#[track_caller]` functions,
+    /// or the function's scope.
+    pub fn caller_location_span<T>(
+        &self,
+        mut source_info: SourceInfo,
+        caller_location: Option<T>,
+        tcx: TyCtxt<'tcx>,
+        from_span: impl FnOnce(Span) -> T,
+    ) -> T {
+        loop {
+            let scope_data = &self.source_scopes[source_info.scope];
+
+            if let Some((callee, callsite_span)) = scope_data.inlined {
+                // Stop inside the most nested non-`#[track_caller]` function,
+                // before ever reaching its caller (which is irrelevant).
+                if !callee.def.requires_caller_location(tcx) {
+                    return from_span(source_info.span);
+                }
+                source_info.span = callsite_span;
+            }
+
+            // Skip past all of the parents with `inlined: None`.
+            match scope_data.inlined_parent_scope {
+                Some(parent) => source_info.scope = parent,
+                None => break,
+            }
+        }
+
+        // No inlined `SourceScope`s, or all of them were `#[track_caller]`.
+        caller_location.unwrap_or_else(|| from_span(source_info.span))
+    }
 }
 
 #[derive(Copy, Clone, PartialEq, Eq, Debug, TyEncodable, TyDecodable, HashStable)]