From 7014774fd014fb19d135f2f92dbaed46073d9c64 Mon Sep 17 00:00:00 2001
From: Philip Craig <philipjcraig@gmail.com>
Date: Sun, 25 Aug 2019 13:01:46 +1000
Subject: [PATCH] debuginfo: give unique names to closure and generator types

Closure types have been moved to the namespace where they
are defined, and both closure and generator type names now
include the disambiguator.

This fixes an exception when lldb prints nested closures.

Fixes #57822
---
 .../debuginfo/metadata.rs                     | 10 +++-
 .../debuginfo/type_names.rs                   | 12 +++-
 src/test/debuginfo/issue-57822.rs             | 55 +++++++++++++++++++
 3 files changed, 72 insertions(+), 5 deletions(-)
 create mode 100644 src/test/debuginfo/issue-57822.rs

diff --git a/src/librustc_codegen_llvm/debuginfo/metadata.rs b/src/librustc_codegen_llvm/debuginfo/metadata.rs
index 51e789b17880..928532a1f476 100644
--- a/src/librustc_codegen_llvm/debuginfo/metadata.rs
+++ b/src/librustc_codegen_llvm/debuginfo/metadata.rs
@@ -683,11 +683,13 @@ pub fn type_metadata(
         }
         ty::Closure(def_id, substs) => {
             let upvar_tys : Vec<_> = substs.upvar_tys(def_id, cx.tcx).collect();
+            let containing_scope = get_namespace_for_item(cx, def_id);
             prepare_tuple_metadata(cx,
                                    t,
                                    &upvar_tys,
                                    unique_type_id,
-                                   usage_site_span).finalize(cx)
+                                   usage_site_span,
+                                   Some(containing_scope)).finalize(cx)
         }
         ty::Generator(def_id, substs,  _) => {
             let upvar_tys : Vec<_> = substs.prefix_tys(def_id, cx.tcx).map(|t| {
@@ -728,7 +730,8 @@ pub fn type_metadata(
                                    t,
                                    &tys,
                                    unique_type_id,
-                                   usage_site_span).finalize(cx)
+                                   usage_site_span,
+                                   NO_SCOPE_METADATA).finalize(cx)
         }
         _ => {
             bug!("debuginfo: unexpected type in type_metadata: {:?}", t)
@@ -1205,6 +1208,7 @@ fn prepare_tuple_metadata(
     component_types: &[Ty<'tcx>],
     unique_type_id: UniqueTypeId,
     span: Span,
+    containing_scope: Option<&'ll DIScope>,
 ) -> RecursiveTypeDescription<'ll, 'tcx> {
     let tuple_name = compute_debuginfo_type_name(cx.tcx, tuple_type, false);
 
@@ -1212,7 +1216,7 @@ fn prepare_tuple_metadata(
                                          tuple_type,
                                          &tuple_name[..],
                                          unique_type_id,
-                                         NO_SCOPE_METADATA);
+                                         containing_scope);
 
     create_and_register_recursive_type_forward_declaration(
         cx,
diff --git a/src/librustc_codegen_ssa/debuginfo/type_names.rs b/src/librustc_codegen_ssa/debuginfo/type_names.rs
index ea39913d4b91..b7c782528de0 100644
--- a/src/librustc_codegen_ssa/debuginfo/type_names.rs
+++ b/src/librustc_codegen_ssa/debuginfo/type_names.rs
@@ -190,11 +190,19 @@ pub fn push_debuginfo_type_name<'tcx>(
             // processing
             visited.remove(t);
         },
-        ty::Closure(..) => {
+        ty::Closure(def_id, ..) => {
             output.push_str("closure");
+            let disambiguator = tcx.def_key(def_id).disambiguated_data.disambiguator;
+            if disambiguator != 0 {
+                output.push_str(&format!("-{}", disambiguator));
+            }
         }
-        ty::Generator(..) => {
+        ty::Generator(def_id, ..) => {
             output.push_str("generator");
+            let disambiguator = tcx.def_key(def_id).disambiguated_data.disambiguator;
+            if disambiguator != 0 {
+                output.push_str(&format!("-{}", disambiguator));
+            }
         }
         ty::Error |
         ty::Infer(_) |
diff --git a/src/test/debuginfo/issue-57822.rs b/src/test/debuginfo/issue-57822.rs
new file mode 100644
index 000000000000..ba5e8e0f2192
--- /dev/null
+++ b/src/test/debuginfo/issue-57822.rs
@@ -0,0 +1,55 @@
+// This test makes sure that the LLDB pretty printer does not throw an exception
+// for nested closures and generators.
+
+// Require LLVM with DW_TAG_variant_part and a gdb that can read it.
+// min-system-llvm-version: 8.0
+// min-gdb-version: 8.2
+// ignore-tidy-linelength
+
+// compile-flags:-g
+
+// === GDB TESTS ===================================================================================
+
+// gdb-command:run
+
+// gdb-command:print g
+// gdb-check:$1 = issue_57822::main::closure-1 (issue_57822::main::closure (1))
+
+// gdb-command:print b
+// gdb-check:$2 = issue_57822::main::generator-3 {__0: issue_57822::main::generator-2 {__0: 2, <<variant>>: {[...]}}, <<variant>>: {[...]}}
+
+// === LLDB TESTS ==================================================================================
+
+// lldb-command:run
+
+// lldb-command:print g
+// lldbg-check:(issue_57822::main::closure-1) $0 = closure-1(closure(1))
+
+// lldb-command:print b
+// lldbg-check:(issue_57822::main::generator-3) $1 = generator-3(generator-2(2))
+
+#![feature(omit_gdb_pretty_printer_section, generators, generator_trait)]
+#![omit_gdb_pretty_printer_section]
+
+use std::ops::Generator;
+use std::pin::Pin;
+
+fn main() {
+    let mut x = 1;
+    let f = move || x;
+    let g = move || f();
+
+    let mut y = 2;
+    let mut a = move || {
+        y += 1;
+        yield;
+    };
+    let mut b = move || {
+        Pin::new(&mut a).resume();
+        yield;
+    };
+
+    zzz(); // #break
+}
+
+fn zzz() { () }