2 files changed, 50 insertions, 12 deletions
diff --git a/src/librustc_codegen_ssa/mir/block.rs b/src/librustc_codegen_ssa/mir/block.rs
index ce703f24335..e68349660ba 100644
--- a/src/librustc_codegen_ssa/mir/block.rs
+++ b/src/librustc_codegen_ssa/mir/block.rs
@@ -774,6 +774,18 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 &fn_abi.args[first_args.len()..])
         }
 
+        let needs_location =
+            instance.map_or(false, |i| i.def.requires_caller_location(self.cx.tcx()));
+        if needs_location {
+            assert_eq!(
+                fn_abi.args.len(), args.len() + 1,
+                "#[track_caller] fn's must have 1 more argument in their ABI than in their MIR",
+            );
+            let location = self.get_caller_location(&mut bx, span);
+            let last_arg = fn_abi.args.last().unwrap();
+            self.codegen_argument(&mut bx, location, &mut llargs, last_arg);
+        }
+
         let fn_ptr = match (llfn, instance) {
             (Some(llfn), _) => llfn,
             (None, Some(instance)) => bx.get_fn_addr(instance),
@@ -1010,14 +1022,16 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         bx: &mut Bx,
         span: Span,
     ) -> OperandRef<'tcx, Bx::Value> {
-        let topmost = span.ctxt().outer_expn().expansion_cause().unwrap_or(span);
-        let caller = bx.tcx().sess.source_map().lookup_char_pos(topmost.lo());
-        let const_loc = bx.tcx().const_caller_location((
-            Symbol::intern(&caller.file.name.to_string()),
-            caller.line as u32,
-            caller.col_display as u32 + 1,
-        ));
-        OperandRef::from_const(bx, const_loc)
+        self.caller_location.unwrap_or_else(|| {
+            let topmost = span.ctxt().outer_expn().expansion_cause().unwrap_or(span);
+            let caller = bx.tcx().sess.source_map().lookup_char_pos(topmost.lo());
+            let const_loc = bx.tcx().const_caller_location((
+                Symbol::intern(&caller.file.name.to_string()),
+                caller.line as u32,
+                caller.col_display as u32 + 1,
+            ));
+            OperandRef::from_const(bx, const_loc)
+        })
     }
 
     fn get_personality_slot(
diff --git a/src/librustc_codegen_ssa/mir/mod.rs b/src/librustc_codegen_ssa/mir/mod.rs
index 3a157ca24a4..33e343de86b 100644
--- a/src/librustc_codegen_ssa/mir/mod.rs
+++ b/src/librustc_codegen_ssa/mir/mod.rs
@@ -77,6 +77,9 @@ pub struct FunctionCx<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> {
     /// All `VarDebuginfo` from the MIR body, partitioned by `Local`.
     /// This is `None` if no variable debuginfo/names are needed.
     per_local_var_debug_info: Option<IndexVec<mir::Local, Vec<&'tcx mir::VarDebugInfo<'tcx>>>>,
+
+    /// Caller location propagated if this function has `#[track_caller]`.
+    caller_location: Option<OperandRef<'tcx, Bx::Value>>,
 }
 
 impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
@@ -172,13 +175,14 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
         locals: IndexVec::new(),
         debug_context,
         per_local_var_debug_info: debuginfo::per_local_var_debug_info(cx.tcx(), mir_body),
+        caller_location: None,
     };
 
     let memory_locals = analyze::non_ssa_locals(&fx);
 
     // Allocate variable and temp allocas
     fx.locals = {
-        let args = arg_local_refs(&mut bx, &fx, &memory_locals);
+        let args = arg_local_refs(&mut bx, &mut fx, &memory_locals);
 
         let mut allocate_local = |local| {
             let decl = &mir_body.local_decls[local];
@@ -320,14 +324,14 @@ fn create_funclets<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
 /// indirect.
 fn arg_local_refs<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
     bx: &mut Bx,
-    fx: &FunctionCx<'a, 'tcx, Bx>,
+    fx: &mut FunctionCx<'a, 'tcx, Bx>,
     memory_locals: &BitSet<mir::Local>,
 ) -> Vec<LocalRef<'tcx, Bx::Value>> {
     let mir = fx.mir;
     let mut idx = 0;
     let mut llarg_idx = fx.fn_abi.ret.is_indirect() as usize;
 
-    mir.args_iter().enumerate().map(|(arg_index, local)| {
+    let args = mir.args_iter().enumerate().map(|(arg_index, local)| {
         let arg_decl = &mir.local_decls[local];
 
         if Some(local) == mir.spread_arg {
@@ -423,7 +427,27 @@ fn arg_local_refs<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
             bx.store_fn_arg(arg, &mut llarg_idx, tmp);
             LocalRef::Place(tmp)
         }
-    }).collect()
+    }).collect::<Vec<_>>();
+
+    if fx.instance.def.requires_caller_location(bx.tcx()) {
+        assert_eq!(
+            fx.fn_abi.args.len(), args.len() + 1,
+            "#[track_caller] fn's must have 1 more argument in their ABI than in their MIR",
+        );
+
+        let arg = fx.fn_abi.args.last().unwrap();
+        match arg.mode {
+            PassMode::Direct(_) => (),
+            _ => bug!("caller location must be PassMode::Direct, found {:?}", arg.mode),
+        }
+
+        fx.caller_location = Some(OperandRef {
+            val: OperandValue::Immediate(bx.get_param(llarg_idx)),
+            layout: arg.layout,
+        });
+    }
+
+    args
 }
 
 mod analyze;