Rollup merge of rust-lang#39678 - vadimcn:top-level-expn, r=michaelwo…

…erister

Exclude top-level macro expansions from source location override.

It occurred to me that a simple heuristic can address the issue rust-lang#36382: any macros that expand into items (including `include!()`) don't need to be stepped over because there's not code to step through above a function scope level.

r? @michaelwoerister

src/librustc_trans/mir/mod.rs

@@ -138,13 +138,20 @@ impl<'a, 'tcx> MirContext<'a, 'tcx> {
             while span.expn_id != NO_EXPANSION && span.expn_id != COMMAND_LINE_EXPN {
                 if let Some(callsite_span) = cm.with_expn_info(span.expn_id,
                                                     |ei| ei.map(|ei| ei.call_site.clone())) {
+                    // When the current function itself is a result of macro expansion,
+                    // we stop at the function body level because no line stepping can occurr
+                    // at the level above that.
+                    if self.mir.span.expn_id != NO_EXPANSION &&
+                       span.expn_id == self.mir.span.expn_id {
+                        break;
+                    }
                     span = callsite_span;
                 } else {
                     break;
                 }
             }
             let scope = self.scope_metadata_for_loc(source_info.scope, span.lo);
-            // Use span of the outermost call site, while keeping the original lexical scope
+            // Use span of the outermost expansion site, while keeping the original lexical scope.
             (scope, span)
         }
     }

src/test/debuginfo/macro-stepping.inc

@@ -0,0 +1,17 @@
+// Copyright 2013-2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+fn included() {
+    foo!(); // #inc-loc1
+
+    foo2!(); // #inc-loc2
+
+    zzz(); // #inc-loc3
+}

src/test/debuginfo/macro-stepping.rs

@@ -44,6 +44,17 @@ extern crate macro_stepping; // exports new_scope!()
 // gdb-command:frame
 // gdb-check:[...]#loc6[...]
 
+// gdb-command:continue
+// gdb-command:step
+// gdb-command:frame
+// gdb-check:[...]#inc-loc1[...]
+// gdb-command:next
+// gdb-command:frame
+// gdb-check:[...]#inc-loc2[...]
+// gdb-command:next
+// gdb-command:frame
+// gdb-check:[...]#inc-loc3[...]
+
 // === LLDB TESTS ==================================================================================
 
 // lldb-command:set set stop-line-count-before 0
@@ -68,6 +79,17 @@ extern crate macro_stepping; // exports new_scope!()
 // lldb-command:frame select
 // lldb-check:[...]#loc5[...]
 
+// lldb-command:continue
+// lldb-command:step
+// lldb-command:frame select
+// lldb-check:[...]#inc-loc1[...]
+// lldb-command:next
+// lldb-command:frame select
+// lldb-check:[...]#inc-loc2[...]
+// lldb-command:next
+// lldb-command:frame select
+// lldb-check:[...]#inc-loc3[...]
+
 macro_rules! foo {
     () => {
         let a = 1;
@@ -99,6 +121,10 @@ fn main() {
              "world");
 
     zzz(); // #loc6
+
+    included(); // #break
 }
 
 fn zzz() {()}
+
+include!("macro-stepping.inc");