Add template parameter debuginfo to generic types

This changes debuginfo generation to add template parameters to
generic types.  With this change the DWARF now has
DW_TAG_template_type_param for types, not just for functions, like:

 <2><40d>: Abbrev Number: 6 (DW_TAG_structure_type)
    <40e>   DW_AT_name        : (indirect string, offset: 0x375): Generic<i32>
    <412>   DW_AT_byte_size   : 4
    <413>   DW_AT_alignment   : 4
...
 <3><41f>: Abbrev Number: 8 (DW_TAG_template_type_param)
    <420>   DW_AT_type        : <0x42a>
    <424>   DW_AT_name        : (indirect string, offset: 0xa65e): T

Closes #9224

9 files changed, 115 insertions, 18 deletions

diff --git a/src/librustc_codegen_llvm/debuginfo/metadata.rs b/src/librustc_codegen_llvm/debuginfo/metadata.rs
index 81f2769800d..cd21ef6bfa8 100644
--- a/src/librustc_codegen_llvm/debuginfo/metadata.rs
+++ b/src/librustc_codegen_llvm/debuginfo/metadata.rs
@@ -22,7 +22,7 @@ use abi;
 use value::Value;
 
 use llvm;
-use llvm::debuginfo::{DIType, DIFile, DIScope, DIDescriptor,
+use llvm::debuginfo::{DIArray, DIType, DIFile, DIScope, DIDescriptor,
                       DICompositeType, DILexicalBlock, DIFlags};
 use llvm_util;
 
@@ -35,12 +35,14 @@ use rustc_data_structures::fingerprint::Fingerprint;
 use rustc::ty::Instance;
 use common::CodegenCx;
 use rustc::ty::{self, AdtKind, ParamEnv, Ty, TyCtxt};
-use rustc::ty::layout::{self, Align, HasDataLayout, Integer, IntegerExt, LayoutOf,
+use rustc::ty::layout::{self, Align, Integer, IntegerExt, LayoutOf,
                         PrimitiveExt, Size, TyLayout};
+use rustc::ty::subst::UnpackedKind;
 use rustc::session::config;
 use rustc::util::nodemap::FxHashMap;
 use rustc_fs_util::path2cstr;
 use rustc_data_structures::small_c_str::SmallCStr;
+use rustc_target::abi::HasDataLayout;
 
 use libc::{c_uint, c_longlong};
 use std::ffi::CString;
@@ -273,6 +275,7 @@ impl RecursiveTypeDescription<'ll, 'tcx> {
 
                 // ... and attach them to the stub to complete it.
                 set_members_of_composite_type(cx,
+                                              unfinished_type,
                                               member_holding_stub,
                                               member_descriptions);
                 return MetadataCreationResult::new(metadata_stub, true);
@@ -1214,6 +1217,7 @@ impl EnumMemberDescriptionFactory<'ll, 'tcx> {
                     member_description_factory.create_member_descriptions(cx);
 
                 set_members_of_composite_type(cx,
+                                              self.enum_type,
                                               variant_type_metadata,
                                               member_descriptions);
                 vec![
@@ -1254,6 +1258,7 @@ impl EnumMemberDescriptionFactory<'ll, 'tcx> {
                         .create_member_descriptions(cx);
 
                     set_members_of_composite_type(cx,
+                                                  self.enum_type,
                                                   variant_type_metadata,
                                                   member_descriptions);
                     MemberDescription {
@@ -1295,6 +1300,7 @@ impl EnumMemberDescriptionFactory<'ll, 'tcx> {
                         member_description_factory.create_member_descriptions(cx);
 
                     set_members_of_composite_type(cx,
+                                                  self.enum_type,
                                                   variant_type_metadata,
                                                   variant_member_descriptions);
 
@@ -1354,6 +1360,7 @@ impl EnumMemberDescriptionFactory<'ll, 'tcx> {
                             .create_member_descriptions(cx);
 
                         set_members_of_composite_type(cx,
+                                                      self.enum_type,
                                                       variant_type_metadata,
                                                       member_descriptions);
 
@@ -1765,13 +1772,15 @@ fn composite_type_metadata(
                                                      containing_scope);
     // ... and immediately create and add the member descriptions.
     set_members_of_composite_type(cx,
+                                  composite_type,
                                   composite_type_metadata,
                                   member_descriptions);
 
     composite_type_metadata
 }
 
-fn set_members_of_composite_type(cx: &CodegenCx<'ll, '_>,
+fn set_members_of_composite_type(cx: &CodegenCx<'ll, 'tcx>,
+                                 composite_type: Ty<'tcx>,
                                  composite_type_metadata: &'ll DICompositeType,
                                  member_descriptions: Vec<MemberDescription<'ll>>) {
     // In some rare cases LLVM metadata uniquing would lead to an existing type
@@ -1815,10 +1824,57 @@ fn set_members_of_composite_type(cx: &CodegenCx<'ll, '_>,
         })
         .collect();
 
+    let type_params = compute_type_parameters(cx, composite_type);
     unsafe {
         let type_array = create_DIArray(DIB(cx), &member_metadata[..]);
-        llvm::LLVMRustDICompositeTypeSetTypeArray(
-            DIB(cx), composite_type_metadata, type_array);
+        llvm::LLVMRustDICompositeTypeReplaceArrays(
+            DIB(cx), composite_type_metadata, Some(type_array), type_params);
+    }
+}
+
+// Compute the type parameters for a type, if any, for the given
+// metadata.
+fn compute_type_parameters(cx: &CodegenCx<'ll, 'tcx>, ty: Ty<'tcx>) -> Option<&'ll DIArray> {
+    if let ty::Adt(def, substs) = ty.sty {
+        if !substs.types().next().is_none() {
+            let generics = cx.tcx.generics_of(def.did);
+            let names = get_parameter_names(cx, generics);
+            let template_params: Vec<_> = substs.iter().zip(names).filter_map(|(kind, name)| {
+                if let UnpackedKind::Type(ty) = kind.unpack() {
+                    let actual_type = cx.tcx.normalize_erasing_regions(ParamEnv::reveal_all(), ty);
+                    let actual_type_metadata =
+                        type_metadata(cx, actual_type, syntax_pos::DUMMY_SP);
+                    let name = SmallCStr::new(&name.as_str());
+                    Some(unsafe {
+
+                        Some(llvm::LLVMRustDIBuilderCreateTemplateTypeParameter(
+                            DIB(cx),
+                            None,
+                            name.as_ptr(),
+                            actual_type_metadata,
+                            unknown_file_metadata(cx),
+                            0,
+                            0,
+                        ))
+                    })
+                } else {
+                    None
+                }
+            }).collect();
+
+            return Some(create_DIArray(DIB(cx), &template_params[..]));
+        }
+    }
+    return Some(create_DIArray(DIB(cx), &[]));
+
+    fn get_parameter_names(cx: &CodegenCx,
+                           generics: &ty::Generics)
+                           -> Vec<InternedString> {
+        let mut names = generics.parent.map_or(vec![], |def_id| {
+            get_parameter_names(cx, cx.tcx.generics_of(def_id))
+        });
+        names.extend(generics.params.iter().map(|param| param.name));
+        names
     }
 }
 
diff --git a/src/librustc_codegen_llvm/llvm/ffi.rs b/src/librustc_codegen_llvm/llvm/ffi.rs
index f1a966d7654..88915c2beb0 100644
--- a/src/librustc_codegen_llvm/llvm/ffi.rs
+++ b/src/librustc_codegen_llvm/llvm/ffi.rs
@@ -1586,9 +1586,10 @@ extern "C" {
                                             LineNo: c_uint)
                                             -> &'a DINameSpace;
 
-    pub fn LLVMRustDICompositeTypeSetTypeArray(Builder: &DIBuilder<'a>,
-                                               CompositeType: &'a DIType,
-                                               TypeArray: &'a DIArray);
+    pub fn LLVMRustDICompositeTypeReplaceArrays(Builder: &DIBuilder<'a>,
+                                                CompositeType: &'a DIType,
+                                                Elements: Option<&'a DIArray>,
+                                                Params: Option<&'a DIArray>);
 
 
     pub fn LLVMRustDIBuilderCreateDebugLocation(Context: &'a Context,
diff --git a/src/rustllvm/RustWrapper.cpp b/src/rustllvm/RustWrapper.cpp
index b6e07942f86..908518d87a3 100644
--- a/src/rustllvm/RustWrapper.cpp
+++ b/src/rustllvm/RustWrapper.cpp
@@ -824,11 +824,13 @@ LLVMRustDIBuilderCreateNameSpace(LLVMRustDIBuilderRef Builder,
 }
 
 extern "C" void
-LLVMRustDICompositeTypeSetTypeArray(LLVMRustDIBuilderRef Builder,
-                                    LLVMMetadataRef CompositeTy,
-                                    LLVMMetadataRef TyArray) {
+LLVMRustDICompositeTypeReplaceArrays(LLVMRustDIBuilderRef Builder,
+                                     LLVMMetadataRef CompositeTy,
+                                     LLVMMetadataRef Elements,
+                                     LLVMMetadataRef Params) {
   DICompositeType *Tmp = unwrapDI<DICompositeType>(CompositeTy);
-  Builder->replaceArrays(Tmp, DINodeArray(unwrap<MDTuple>(TyArray)));
+  Builder->replaceArrays(Tmp, DINodeArray(unwrap<MDTuple>(Elements)),
+                         DINodeArray(unwrap<MDTuple>(Params)));
 }
 
 extern "C" LLVMValueRef
diff --git a/src/test/codegen/generic-debug.rs b/src/test/codegen/generic-debug.rs
new file mode 100644
index 00000000000..9d5dbf1cc0a
--- /dev/null
+++ b/src/test/codegen/generic-debug.rs
@@ -0,0 +1,28 @@
+// Copyright 2018 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.
+
+// ignore-tidy-linelength
+// ignore-windows
+
+// compile-flags: -g -C no-prepopulate-passes
+
+// CHECK-LABEL: @main
+// CHECK: {{.*}}DICompositeType{{.*}}tag: DW_TAG_structure_type,{{.*}}name: "Generic<i32>",{{.*}}
+// CHECK: {{.*}}DITemplateTypeParameter{{.*}}name: "Type",{{.*}}
+
+#![allow(dead_code)]
+#![allow(unused_variables)]
+#![allow(unused_assignments)]
+
+pub struct Generic<Type>(Type);
+
+fn main () {
+    let generic = Generic(10);
+}
diff --git a/src/test/debuginfo/associated-types.rs b/src/test/debuginfo/associated-types.rs
index 229f9466b51..c9c23955348 100644
--- a/src/test/debuginfo/associated-types.rs
+++ b/src/test/debuginfo/associated-types.rs
@@ -8,7 +8,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// min-lldb-version: 310
+// Some versions of the non-rust-enabled LLDB print the wrong generic
+// parameter type names in this test.
+// rust-lldb
 
 // compile-flags:-g
 
diff --git a/src/test/debuginfo/generic-method-on-generic-struct.rs b/src/test/debuginfo/generic-method-on-generic-struct.rs
index 97bb9aa98e8..df1f1e3d4ee 100644
--- a/src/test/debuginfo/generic-method-on-generic-struct.rs
+++ b/src/test/debuginfo/generic-method-on-generic-struct.rs
@@ -11,7 +11,10 @@
 // ignore-tidy-linelength
 
 // compile-flags:-g
-// min-lldb-version: 310
+
+// Some versions of the non-rust-enabled LLDB print the wrong generic
+// parameter type names in this test.
+// rust-lldb
 
 // === GDB TESTS ===================================================================================
 
diff --git a/src/test/debuginfo/generic-struct.rs b/src/test/debuginfo/generic-struct.rs
index 4e06a15e1cd..ebaac96946c 100644
--- a/src/test/debuginfo/generic-struct.rs
+++ b/src/test/debuginfo/generic-struct.rs
@@ -9,7 +9,10 @@
 // except according to those terms.
 
 // ignore-tidy-linelength
-// min-lldb-version: 310
+
+// Some versions of the non-rust-enabled LLDB print the wrong generic
+// parameter type names in this test.
+// rust-lldb
 
 // compile-flags:-g
 
diff --git a/src/test/debuginfo/generic-tuple-style-enum.rs b/src/test/debuginfo/generic-tuple-style-enum.rs
index ebd43daf464..8bda0e41915 100644
--- a/src/test/debuginfo/generic-tuple-style-enum.rs
+++ b/src/test/debuginfo/generic-tuple-style-enum.rs
@@ -41,7 +41,7 @@
 // lldb-command:run
 
 // lldb-command:print case1
-// lldbr-check:(generic_tuple_style_enum::Regular<u16, u32, u64>::Case1) case1 = { = 0 = 31868 = 31868 = 31868 = 31868 }
+// lldbr-check:(generic_tuple_style_enum::Regular<u16, u32, u64>::Case1) case1 = { __0 = 0 __1 = 31868 __2 = 31868 __3 = 31868 __4 = 31868 }
 
 // lldb-command:print case2
 // lldbr-check:(generic_tuple_style_enum::Regular<i16, i32, i64>::Case2) case2 = Regular<i16, i32, i64>::Case2 { Case1: 0, Case2: 286331153, Case3: 286331153 }
@@ -50,7 +50,7 @@
 // lldbr-check:(generic_tuple_style_enum::Regular<i16, i32, i64>::Case3) case3 = Regular<i16, i32, i64>::Case3 { Case1: 0, Case2: 6438275382588823897 }
 
 // lldb-command:print univariant
-// lldbr-check:(generic_tuple_style_enum::Univariant<i64>) univariant = { TheOnlyCase = { = -1 } }
+// lldbr-check:(generic_tuple_style_enum::Univariant<i64>) univariant = Univariant<i64> { TheOnlyCase: Univariant<i64>::TheOnlyCase(-1) }
 
 #![feature(omit_gdb_pretty_printer_section)]
 #![omit_gdb_pretty_printer_section]
diff --git a/src/test/debuginfo/method-on-generic-struct.rs b/src/test/debuginfo/method-on-generic-struct.rs
index 57238961e3f..f4f7bdcecc6 100644
--- a/src/test/debuginfo/method-on-generic-struct.rs
+++ b/src/test/debuginfo/method-on-generic-struct.rs
@@ -8,7 +8,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// min-lldb-version: 310
+// Some versions of the non-rust-enabled LLDB print the wrong generic
+// parameter type names in this test.
+// rust-lldb
 
 // compile-flags:-g