Rollup merge of #80311 - sivadeilra:natvis, r=petrochenkov

Improvements to NatVis support

NatVis files describe how to display types in some Windows debuggers,
such as Visual Studio, WinDbg, and VS Code.

This commit makes several improvements:

* Adds visualizers for Rc<T>, Weak<T>, and Arc<T>.

* Changes [size] to [len], for consistency with the Rust API.
  Visualizers often use [size] to mirror the size() method on C++ STL
  collections.

* Several visualizers used the PVOID and ULONG typedefs. These are part
  of the Windows API; they are not guaranteed to always be defined in a
  pure Rust DLL/EXE. I converted PVOID to `void*` and `ULONG` to
  `unsigned long`.

* Cosmetic change: Removed {} braces around the visualized display
  for `Option` types. They now display simply as `Some(value)` or
  `None`, which reflects what is written in source code.

* The visualizer for `alloc::string::String` makes assumptions about
  the layout of `String` (it casts `String*` to another type), rather
  than using symbolic expressions. This commit changes the visualizer
  so that it simply uses symbolic expressions to access the string
  data and string length.

* The visualizers for `str` and `String` now place the character data
  array under a synthetic `[chars]` node. When expanding a `String`
  node, users rarely want to see an array of characters. This just places
  them behind one expansion node / level.

6 files changed, 71 insertions, 49 deletions

diff --git a/src/etc/natvis/intrinsic.natvis b/src/etc/natvis/intrinsic.natvis
index 874550da8b0..030892a432b 100644
--- a/src/etc/natvis/intrinsic.natvis
+++ b/src/etc/natvis/intrinsic.natvis
@@ -4,17 +4,21 @@
     <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>
+      <Item Name="[len]" ExcludeView="simple">length</Item>
+      <Synthetic Name="[chars]">
+        <Expand>
+          <ArrayItems>
+            <Size>length</Size>
+            <ValuePointer>data_ptr</ValuePointer>
+          </ArrayItems>
+        </Expand>
+      </Synthetic>
     </Expand>
   </Type>
   <Type Name="slice&lt;*&gt;">
-    <DisplayString>{{ length={length} }}</DisplayString>
+    <DisplayString>{{ len={length} }}</DisplayString>
     <Expand>
-      <Item Name="[size]" ExcludeView="simple">length</Item>
+      <Item Name="[len]" ExcludeView="simple">length</Item>
       <ArrayItems>
         <Size>length</Size>
         <ValuePointer>data_ptr</ValuePointer>
diff --git a/src/etc/natvis/liballoc.natvis b/src/etc/natvis/liballoc.natvis
index de30b58526a..cfaafc5734b 100644
--- a/src/etc/natvis/liballoc.natvis
+++ b/src/etc/natvis/liballoc.natvis
@@ -1,9 +1,9 @@
 <?xml version="1.0" encoding="utf-8"?>
 <AutoVisualizer xmlns="http://schemas.microsoft.com/vstudio/debugger/natvis/2010">
   <Type Name="alloc::vec::Vec&lt;*&gt;">
-    <DisplayString>{{ size={len} }}</DisplayString>
+    <DisplayString>{{ len={len} }}</DisplayString>
     <Expand>
-      <Item Name="[size]" ExcludeView="simple">len</Item>
+      <Item Name="[len]" ExcludeView="simple">len</Item>
       <Item Name="[capacity]" ExcludeView="simple">buf.cap</Item>
       <ArrayItems>
         <Size>len</Size>
@@ -12,9 +12,9 @@
     </Expand>
   </Type>
   <Type Name="alloc::collections::vec_deque::VecDeque&lt;*&gt;">
-    <DisplayString>{{ size={tail &lt;= head ? head - tail : buf.cap - tail + head} }}</DisplayString>
+    <DisplayString>{{ len={tail &lt;= head ? head - tail : buf.cap - tail + head} }}</DisplayString>
     <Expand>
-      <Item Name="[size]" ExcludeView="simple">tail &lt;= head ? head - tail : buf.cap - tail + head</Item>
+      <Item Name="[len]" ExcludeView="simple">tail &lt;= head ? head - tail : buf.cap - tail + head</Item>
       <Item Name="[capacity]" ExcludeView="simple">buf.cap</Item>
       <CustomListItems>
         <Variable Name="i" InitialValue="tail" />
@@ -31,7 +31,7 @@
     </Expand>
   </Type>
   <Type Name="alloc::collections::linked_list::LinkedList&lt;*&gt;">
-    <DisplayString>{{ size={len} }}</DisplayString>
+    <DisplayString>{{ len={len} }}</DisplayString>
     <Expand>
       <LinkedListItems>
         <Size>len</Size>
@@ -42,15 +42,37 @@
     </Expand>
   </Type>
   <Type Name="alloc::string::String">
-    <DisplayString>{*(char**)this,[vec.len]s8}</DisplayString>
-    <StringView>*(char**)this,[vec.len]s8</StringView>
+    <DisplayString>{(char*)vec.buf.ptr.pointer,[vec.len]s8}</DisplayString>
+    <StringView>(char*)vec.buf.ptr.pointer,[vec.len]s8</StringView>
     <Expand>
-      <Item Name="[size]" ExcludeView="simple">vec.len</Item>
+      <Item Name="[len]" ExcludeView="simple">vec.len</Item>
       <Item Name="[capacity]" ExcludeView="simple">vec.buf.cap</Item>
-      <ArrayItems>
-        <Size>vec.len</Size>
-        <ValuePointer>*(char**)this</ValuePointer>
-      </ArrayItems>
+      <Synthetic Name="[chars]">
+        <Expand>
+          <ArrayItems>
+            <Size>vec.len</Size>
+            <ValuePointer>(char*)vec.buf.ptr.pointer</ValuePointer>
+          </ArrayItems>
+        </Expand>
+      </Synthetic>
+    </Expand>
+  </Type>
+  <Type Name="alloc::rc::Rc&lt;*&gt;">
+    <DisplayString>{ptr.pointer->value}</DisplayString>
+    <Expand>
+      <ExpandedItem>ptr.pointer->value</ExpandedItem>
+    </Expand>
+  </Type>
+  <Type Name="alloc::sync::Arc&lt;*&gt;">
+    <DisplayString>{ptr.pointer->data}</DisplayString>
+    <Expand>
+      <ExpandedItem>ptr.pointer->data</ExpandedItem>
+    </Expand>
+  </Type>
+  <Type Name="alloc::sync::Weak&lt;*&gt;">
+    <DisplayString>{ptr.pointer->data}</DisplayString>
+    <Expand>
+      <ExpandedItem>ptr.pointer->data</ExpandedItem>
     </Expand>
   </Type>
 </AutoVisualizer>
diff --git a/src/etc/natvis/libcore.natvis b/src/etc/natvis/libcore.natvis
index 0e703b3b950..984a8bfb13c 100644
--- a/src/etc/natvis/libcore.natvis
+++ b/src/etc/natvis/libcore.natvis
@@ -6,34 +6,28 @@
       <Item Name="[ptr]">pointer</Item>
     </Expand>
   </Type>
+
   <Type Name="core::ptr::Shared&lt;*&gt;">
     <DisplayString>{{ Shared {pointer} }}</DisplayString>
     <Expand>
       <Item Name="[ptr]">pointer</Item>
     </Expand>
   </Type>
+
   <Type Name="core::option::Option&lt;*&gt;">
-    <DisplayString Condition="RUST$ENUM$DISR == 0x0">{{ None }}</DisplayString>
-    <DisplayString Condition="RUST$ENUM$DISR == 0x1">{{ Some {__0} }}</DisplayString>
+    <DisplayString Condition="RUST$ENUM$DISR == 0x0">None</DisplayString>
+    <DisplayString Condition="RUST$ENUM$DISR == 0x1">Some({__0})</DisplayString>
     <Expand>
-      <Item Name="[size]" ExcludeView="simple">(ULONG)(RUST$ENUM$DISR != 0)</Item>
-      <Item Name="[value]" ExcludeView="simple">__0</Item>
-      <ArrayItems>
-        <Size>(ULONG)(RUST$ENUM$DISR != 0)</Size>
-        <ValuePointer>&amp;__0</ValuePointer>
-      </ArrayItems>
+      <Item Name="[value]" ExcludeView="simple" Condition="RUST$ENUM$DISR == 1">__0</Item>
     </Expand>
   </Type>
+
   <Type Name="core::option::Option&lt;*&gt;" Priority="MediumLow">
-    <DisplayString Condition="*(PVOID *)this == nullptr">{{ None }}</DisplayString>
-    <DisplayString>{{ Some {($T1 *)this} }}</DisplayString>
+    <DisplayString Condition="*(void**)this == nullptr">None</DisplayString>
+    <DisplayString>Some({($T1 *)this})</DisplayString>
     <Expand>
-      <Item Name="[size]" ExcludeView="simple">(ULONG)(*(PVOID *)this != nullptr)</Item>
-      <Item Name="[value]" ExcludeView="simple" Condition="*(PVOID *)this != nullptr">($T1 *)this</Item>
-      <ArrayItems>
-        <Size>(ULONG)(*(PVOID *)this != nullptr)</Size>
-        <ValuePointer>($T1 *)this</ValuePointer>
-      </ArrayItems>
+      <Item Name="Some" ExcludeView="simple" Condition="*(void**)this != nullptr">($T1 *)this</Item>
     </Expand>
   </Type>
+
 </AutoVisualizer>
\ No newline at end of file
diff --git a/src/etc/natvis/libstd.natvis b/src/etc/natvis/libstd.natvis
index 9550c25f2fc..7e5ee7b13da 100644
--- a/src/etc/natvis/libstd.natvis
+++ b/src/etc/natvis/libstd.natvis
@@ -26,9 +26,9 @@
   -->
 
   <Type Name="std::collections::hash::map::HashMap&lt;*,*,*&gt;">
-    <DisplayString>{{ size={base.table.items} }}</DisplayString>
+    <DisplayString>{{ len={base.table.items} }}</DisplayString>
     <Expand>
-      <Item Name="[size]">base.table.items</Item>
+      <Item Name="[len]">base.table.items</Item>
       <Item Name="[capacity]">base.table.items + base.table.growth_left</Item>
       <Item Name="[state]">base.hash_builder</Item>
 
@@ -50,9 +50,9 @@
   </Type>
 
   <Type Name="std::collections::hash::set::HashSet&lt;*,*&gt;">
-    <DisplayString>{{ size={base.map.table.items} }}</DisplayString>
+    <DisplayString>{{ len={base.map.table.items} }}</DisplayString>
     <Expand>
-      <Item Name="[size]">base.map.table.items</Item>
+      <Item Name="[len]">base.map.table.items</Item>
       <Item Name="[capacity]">base.map.table.items + base.map.table.growth_left</Item>
       <Item Name="[state]">base.map.hash_builder</Item>
 
diff --git a/src/test/debuginfo/pretty-std-collections-hash.rs b/src/test/debuginfo/pretty-std-collections-hash.rs
index 9f59936a92d..7115aec1041 100644
--- a/src/test/debuginfo/pretty-std-collections-hash.rs
+++ b/src/test/debuginfo/pretty-std-collections-hash.rs
@@ -10,8 +10,8 @@
 // cdb-command: g
 
 // cdb-command: dx hash_set,d
-// cdb-check:hash_set,d [...] : { size=15 } [Type: [...]::HashSet<u64, [...]>]
-// cdb-check:    [size]           : 15 [Type: [...]]
+// cdb-check:hash_set,d [...] : { len=15 } [Type: [...]::HashSet<u64, [...]>]
+// cdb-check:    [len]            : 15 [Type: [...]]
 // cdb-check:    [capacity]       : [...]
 // cdb-check:    [[...]] [...]    : 0 [Type: u64]
 // cdb-command: dx hash_set,d
@@ -44,8 +44,8 @@
 // cdb-check:    [[...]] [...]    : 14 [Type: u64]
 
 // cdb-command: dx hash_map,d
-// cdb-check:hash_map,d [...] : { size=15 } [Type: [...]::HashMap<u64, u64, [...]>]
-// cdb-check:    [size]           : 15 [Type: [...]]
+// cdb-check:hash_map,d [...] : { len=15 } [Type: [...]::HashMap<u64, u64, [...]>]
+// cdb-check:    [len]            : 15 [Type: [...]]
 // cdb-check:    [capacity]       : [...]
 // cdb-check:    ["0x0"]          : 0 [Type: unsigned __int64]
 // cdb-command: dx hash_map,d
diff --git a/src/test/debuginfo/pretty-std.rs b/src/test/debuginfo/pretty-std.rs
index 6632488171d..1a99f841250 100644
--- a/src/test/debuginfo/pretty-std.rs
+++ b/src/test/debuginfo/pretty-std.rs
@@ -74,8 +74,8 @@
 // NOTE: While slices have a .natvis entry that works in VS & VS Code, it fails in CDB 10.0.18362.1
 
 // cdb-command: dx vec,d
-// cdb-check:vec,d [...] : { size=4 } [Type: [...]::Vec<u64, alloc::alloc::Global>]
-// cdb-check:    [size]           : 4 [Type: [...]]
+// cdb-check:vec,d [...] : { len=4 } [Type: [...]::Vec<u64, alloc::alloc::Global>]
+// cdb-check:    [len]            : 4 [Type: [...]]
 // cdb-check:    [capacity]       : [...] [Type: [...]]
 // cdb-check:    [0]              : 4 [Type: unsigned __int64]
 // cdb-check:    [1]              : 5 [Type: unsigned __int64]
@@ -89,8 +89,10 @@
 // cdb-command: dx string
 // cdb-check:string           : "IAMA string!" [Type: [...]::String]
 // cdb-check:    [<Raw View>]     [Type: [...]::String]
-// cdb-check:    [size]           : 0xc [Type: [...]]
+// cdb-check:    [len]            : 0xc [Type: [...]]
 // cdb-check:    [capacity]       : 0xc [Type: [...]]
+
+// cdb-command: dx -r2 string
 // cdb-check:    [0]              : 73 'I' [Type: char]
 // cdb-check:    [1]              : 65 'A' [Type: char]
 // cdb-check:    [2]              : 77 'M' [Type: char]
@@ -109,11 +111,11 @@
 // NOTE: OsString doesn't have a .natvis entry yet.
 
 // cdb-command: dx some
-// cdb-check:some             : { Some 8 } [Type: [...]::Option<i16>]
+// cdb-check:some             : Some(8) [Type: [...]::Option<i16>]
 // cdb-command: dx none
-// cdb-check:none             : { None } [Type: [...]::Option<i64>]
+// cdb-check:none             : None [Type: [...]::Option<i64>]
 // cdb-command: dx some_string
-// cdb-check:some_string      : { Some "IAMA optional string!" } [[...]::Option<[...]::String>]
+// cdb-check:some_string      : Some("IAMA optional string!") [[...]::Option<[...]::String>]
 
 #![allow(unused_variables)]
 use std::ffi::OsString;