Embed MSVC .natvis files into .pdbs and mangle debuginfo for &str, *T, and [T].

src/etc/natvis/intrinsic.natvis

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8"?>
+<AutoVisualizer xmlns="http://schemas.microsoft.com/vstudio/debugger/natvis/2010">
+  <Type Name="str">
+    <DisplayString>{data_ptr,[length]s8}</DisplayString>
+    <StringView>data_ptr,[length]s8</StringView>
+    <Expand>
+      <Item Name="[size]" ExcludeView="simple">length</Item>
+      <ArrayItems>
+        <Size>length</Size>
+        <ValuePointer>data_ptr</ValuePointer>
+      </ArrayItems>
+    </Expand>
+  </Type>
+  <Type Name="slice&lt;*&gt;">
+    <DisplayString>{{ length={length} }}</DisplayString>
+    <Expand>
+      <Item Name="[size]" ExcludeView="simple">length</Item>
+      <ArrayItems>
+        <Size>length</Size>
+        <ValuePointer>data_ptr</ValuePointer>
+      </ArrayItems>
+    </Expand>
+  </Type>
+</AutoVisualizer>

src/etc/natvis/liballoc.natvis

@@ -42,8 +42,8 @@
     </Expand>
   </Type>
   <Type Name="alloc::string::String">
-    <DisplayString>{*(char**)this,[vec.len]}</DisplayString>
-    <StringView>*(char**)this,[vec.len]</StringView>
+    <DisplayString>{*(char**)this,[vec.len]s8}</DisplayString>
+    <StringView>*(char**)this,[vec.len]s8</StringView>
     <Expand>
       <Item Name="[size]" ExcludeView="simple">vec.len</Item>
       <Item Name="[capacity]" ExcludeView="simple">vec.buf.cap</Item>

src/librustc_trans/back/linker.rs

@@ -475,6 +475,27 @@ impl<'a> Linker for MsvcLinker<'a> {
         // This will cause the Microsoft linker to generate a PDB file
         // from the CodeView line tables in the object files.
         self.cmd.arg("/DEBUG");
+
+        // This will cause the Microsoft linker to embed .natvis info into the the PDB file
+        let sysroot = self.sess.sysroot();
+        let natvis_dir_path = sysroot.join("lib\\rustlib\\etc");
+        if let Ok(natvis_dir) = fs::read_dir(&natvis_dir_path) {
+            for entry in natvis_dir {
+                match entry {
+                    Ok(entry) => {
+                        let path = entry.path();
+                        if path.extension() == Some("natvis".as_ref()) {
+                            let mut arg = OsString::from("/NATVIS:");
+                            arg.push(path);
+                            self.cmd.arg(arg);
+                        }
+                    },
+                    Err(err) => {
+                        self.sess.warn(&format!("error enumerating natvis directory: {}", err));
+                    },
+                }
+            }
+        }
     }
 
     // Currently the compiler doesn't use `dllexport` (an LLVM attribute) to

src/librustc_trans/debuginfo/type_names.rs

@@ -36,6 +36,10 @@ pub fn push_debuginfo_type_name<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
                                           t: Ty<'tcx>,
                                           qualified: bool,
                                           output: &mut String) {
+    // When targeting MSVC, emit C++ style type names for compatability with
+    // .natvis visualizers (and perhaps other existing native debuggers?)
+    let cpp_like_names = cx.sess().target.target.options.is_like_msvc;
+
     match t.sty {
         ty::TyBool => output.push_str("bool"),
         ty::TyChar => output.push_str("char"),
@@ -61,21 +65,33 @@ pub fn push_debuginfo_type_name<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
             output.push(')');
         },
         ty::TyRawPtr(ty::TypeAndMut { ty: inner_type, mutbl } ) => {
-            output.push('*');
+            if !cpp_like_names {
+                output.push('*');
+            }
             match mutbl {
                 hir::MutImmutable => output.push_str("const "),
                 hir::MutMutable => output.push_str("mut "),
             }
 
             push_debuginfo_type_name(cx, inner_type, true, output);
+
+            if cpp_like_names {
+                output.push('*');
+            }
         },
         ty::TyRef(_, ty::TypeAndMut { ty: inner_type, mutbl }) => {
-            output.push('&');
+            if !cpp_like_names {
+                output.push('&');
+            }
             if mutbl == hir::MutMutable {
                 output.push_str("mut ");
             }
 
             push_debuginfo_type_name(cx, inner_type, true, output);
+
+            if cpp_like_names {
+                output.push('*');
+            }
         },
         ty::TyArray(inner_type, len) => {
             output.push('[');
@@ -84,9 +100,19 @@ pub fn push_debuginfo_type_name<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
             output.push(']');
         },
         ty::TySlice(inner_type) => {
-            output.push('[');
+            if cpp_like_names {
+                output.push_str("slice<");
+            } else {
+                output.push('[');
+            }
+
             push_debuginfo_type_name(cx, inner_type, true, output);
-            output.push(']');
+
+            if cpp_like_names {
+                output.push('>');
+            } else {
+                output.push(']');
+            }
         },
         ty::TyDynamic(ref trait_data, ..) => {
             if let Some(principal) = trait_data.principal() {