debuginfo: Refactor debuginfo generation for types

This commit
- changes names to use di_node instead of metadata
- uniformly names all functions that build new debuginfo nodes build_xyz_di_node
- renames CrateDebugContext to CodegenUnitDebugContext (which is more accurate)
- moves TypeMap and functions that work directly work with it to a new type_map module
- moves and reimplements enum related builder functions to a new enums module
- splits enum debuginfo building for the native and cpp-like cases, since they are mostly separate
- uses SmallVec instead of Vec in many places
- removes the old infrastructure for dealing with recursion cycles (create_and_register_recursive_type_forward_declaration(), RecursiveTypeDescription, set_members_of_composite_type(), MemberDescription, MemberDescriptionFactory, prepare_xyz_metadata(), etc)
- adds type_map::build_type_with_children() as a replacement for dealing with recursion cycles
- adds many (doc-)comments explaining what's going on
- changes cpp-like naming for C-Style enums so they don't get a enum$<...> name (because the NatVis visualizer does not apply to them)
- fixes detection of what is a C-style enum because some enums where classified as C-style even though they have fields
- changes the position of discriminant debuginfo node so it is consistently nested inside the top-level union instead of, sometimes, next to it

2 files changed, 20 insertions, 19 deletions

diff --git a/src/test/debuginfo/msvc-pretty-enums.rs b/src/test/debuginfo/msvc-pretty-enums.rs
index 642694355ad..a153a9a4228 100644
--- a/src/test/debuginfo/msvc-pretty-enums.rs
+++ b/src/test/debuginfo/msvc-pretty-enums.rs
@@ -4,14 +4,14 @@
 // cdb-command: g
 
 // cdb-command: dx a
-// cdb-check:a                :  Some({...}) [Type: enum$<core::option::Option<enum$<msvc_pretty_enums::CStyleEnum> >, 2, 16, Some>]
-// cdb-check:    [<Raw View>]     [Type: enum$<core::option::Option<enum$<msvc_pretty_enums::CStyleEnum> >, 2, 16, Some>]
+// cdb-check:a                :  Some({...}) [Type: enum$<core::option::Option<msvc_pretty_enums::CStyleEnum>, 2, 16, Some>]
+// cdb-check:    [<Raw View>]     [Type: enum$<core::option::Option<msvc_pretty_enums::CStyleEnum>, 2, 16, Some>]
 // cdb-check:    [variant]        :  Some
 // cdb-check:    [+0x000] __0              : Low (0x2) [Type: msvc_pretty_enums::CStyleEnum]
 
 // cdb-command: dx b
-// cdb-check:b                : None [Type: enum$<core::option::Option<enum$<msvc_pretty_enums::CStyleEnum> >, 2, 16, Some>]
-// cdb-check:    [<Raw View>]     [Type: enum$<core::option::Option<enum$<msvc_pretty_enums::CStyleEnum> >, 2, 16, Some>]
+// cdb-check:b                : None [Type: enum$<core::option::Option<msvc_pretty_enums::CStyleEnum>, 2, 16, Some>]
+// cdb-check:    [<Raw View>]     [Type: enum$<core::option::Option<msvc_pretty_enums::CStyleEnum>, 2, 16, Some>]
 // cdb-check:    [variant]        : None
 
 // cdb-command: dx c
@@ -78,7 +78,7 @@ pub enum NicheLayoutEnum {
     Tag2,
 }
 
-pub enum Empty { }
+pub enum Empty {}
 
 fn main() {
     let a = Some(CStyleEnum::Low);
@@ -97,4 +97,6 @@ fn main() {
     zzz(); // #break
 }
 
-fn zzz() { () }
+fn zzz() {
+    ()
+}
diff --git a/src/test/debuginfo/type-names.rs b/src/test/debuginfo/type-names.rs
index c9692128562..52841d50f64 100644
--- a/src/test/debuginfo/type-names.rs
+++ b/src/test/debuginfo/type-names.rs
@@ -33,10 +33,10 @@
 // gdb-check:type = type_names::mod1::Enum2
 
 // gdb-command:whatis generic_enum_1
-// gdb-check:type = type_names::mod1::mod2::Enum3
+// gdb-check:type = type_names::mod1::mod2::Enum3<type_names::mod1::Struct2>
 
 // gdb-command:whatis generic_enum_2
-// gdb-check:type = type_names::mod1::mod2::Enum3
+// gdb-check:type = type_names::mod1::mod2::Enum3<type_names::Struct1>
 
 // TUPLES
 // gdb-command:whatis tuple1
@@ -159,10 +159,10 @@
 
 // FOREIGN TYPES
 // gdb-command:whatis foreign1
-// gdb-check:type = *mut ForeignType1
+// gdb-check:type = *mut type_names::{extern#0}::ForeignType1
 
 // gdb-command:whatis foreign2
-// gdb-check:type = *mut ForeignType2
+// gdb-check:type = *mut type_names::mod1::{extern#0}::ForeignType2
 
 // === CDB TESTS ==================================================================================
 
@@ -178,9 +178,9 @@
 // cdb-command:dv /t *_enum_*
 // cdb-check:union enum$<type_names::Enum1> simple_enum_1 = [...]
 // cdb-check:union enum$<type_names::Enum1> simple_enum_2 = [...]
-// cdb-check:type_names::mod1::Enum2 simple_enum_3 = [...]
-// cdb-check:type_names::mod1::mod2::Enum3 generic_enum_1 = [...]
-// cdb-check:type_names::mod1::mod2::Enum3 generic_enum_2 = [...]
+// cdb-check:union enum$<type_names::mod1::Enum2> simple_enum_3 = [...]
+// cdb-check:union enum$<type_names::mod1::mod2::Enum3<type_names::mod1::Struct2> > generic_enum_1 = [...]
+// cdb-check:union enum$<type_names::mod1::mod2::Enum3<type_names::Struct1> > generic_enum_2 = [...]
 
 // TUPLES
 // cdb-command:dv /t tuple*
@@ -258,8 +258,8 @@
 
 // FOREIGN TYPES
 // cdb-command:dv /t foreign*
-// cdb-check:struct ForeignType2 * foreign2 = [...]
-// cdb-check:struct ForeignType1 * foreign1 = [...]
+// cdb-check:struct type_names::mod1::extern$0::ForeignType2 * foreign2 = [...]
+// cdb-check:struct type_names::extern$0::ForeignType1 * foreign1 = [...]
 
 #![allow(unused_variables)]
 #![feature(omit_gdb_pretty_printer_section)]
@@ -283,7 +283,6 @@ extern "C" {
 }
 
 mod mod1 {
-    pub use self::Enum2::{Variant1, Variant2};
     pub struct Struct2;
 
     pub enum Enum2 {
@@ -367,14 +366,14 @@ fn main() {
     // Enums
     let simple_enum_1 = Variant1;
     let simple_enum_2 = Variant2(0);
-    let simple_enum_3 = mod1::Variant2(Struct1);
+    let simple_enum_3 = mod1::Enum2::Variant2(Struct1);
 
     let generic_enum_1: mod1::mod2::Enum3<mod1::Struct2> = mod1::mod2::Variant1;
     let generic_enum_2 = mod1::mod2::Variant2(Struct1);
 
     // Tuples
     let tuple1 = (8u32, Struct1, mod1::mod2::Variant2(mod1::Struct2));
-    let tuple2 = ((Struct1, mod1::mod2::Struct3), mod1::Variant1, 'x');
+    let tuple2 = ((Struct1, mod1::mod2::Struct3), mod1::Enum2::Variant1, 'x');
 
     // Box
     let box1 = (Box::new(1f32), 0i32);
@@ -404,7 +403,7 @@ fn main() {
 
     let vec1 = vec![0_usize, 2, 3];
     let slice1 = &*vec1;
-    let vec2 = vec![mod1::Variant2(Struct1)];
+    let vec2 = vec![mod1::Enum2::Variant2(Struct1)];
     let slice2 = &*vec2;
 
     // Trait Objects