Auto merge of #66597 - MaulingMonkey:pr-natvis-std-collections-hash, r=michaelwoerister

debuginfo:  Support for std::collections::Hash* in windows debuggers.

Okay, I finally needed to debug code involving a HashMap!  Added support for HashSet s as well.

r? @michaelwoerister

### Local Testing

Verified these are passing locally:
```cmd
:: cmd.exe
python x.py test --stage 1 --build x86_64-pc-windows-msvc src/test/debuginfo
python x.py test --stage 1 --build i686-pc-windows-msvc src/test/debuginfo
python x.py test --stage 1 src/tools/tidy

:: MinGW MSYS2
./x.py test --stage 1 --build x86_64-pc-windows-gnu src/test/debuginfo
```

### Related Issues

* https://github.com/rust-lang/rust/issues/36503
* https://github.com/rust-lang/rust/issues/40460
* https://github.com/rust-gamedev/wg/issues/20

3 files changed, 200 insertions, 0 deletions

diff --git a/src/bootstrap/dist.rs b/src/bootstrap/dist.rs
index 67907bc8cbf..d0c9e0dbaf4 100644
--- a/src/bootstrap/dist.rs
+++ b/src/bootstrap/dist.rs
@@ -616,6 +616,7 @@ impl Step for DebuggerScripts {
             cp_debugger_script("natvis/intrinsic.natvis");
             cp_debugger_script("natvis/liballoc.natvis");
             cp_debugger_script("natvis/libcore.natvis");
+            cp_debugger_script("natvis/libstd.natvis");
         } else {
             cp_debugger_script("debugger_pretty_printers_common.py");
 
diff --git a/src/etc/natvis/libstd.natvis b/src/etc/natvis/libstd.natvis
new file mode 100644
index 00000000000..b3fc3d17af7
--- /dev/null
+++ b/src/etc/natvis/libstd.natvis
@@ -0,0 +1,102 @@
+<?xml version="1.0" encoding="utf-8"?>
+<AutoVisualizer xmlns="http://schemas.microsoft.com/vstudio/debugger/natvis/2010">
+  <!--
+    std::collection::Hash* container visualizers
+
+    Current std impls:
+      std::collections::hash::set::HashSet<K, S>      is implemented in terms of...
+      std::collections::hash::map::HashMap<K, V, S>   is implemented in terms of...
+      hashbrown::map::HashMap<K, V, S>                is implemented in terms of...
+      hashbrown::raw::RawTable<(K, V)>
+
+    Ideally, we'd teach rustc to scan dependencies/crates for .natvis files so
+    the bulk of this could live alongside the hashbrown crate implementation,
+    and std would just forward using e.g. <ExpandedItem>base</ExpandedItem>.
+
+    However, Given that std...Hash*Set* is currently implemented in terms of
+    hashbrown...Hash*Map*, which would visualize poorly, we want to customize the
+    look/feel at the std type level *anyways*...
+
+    References:
+      https://github.com/rust-lang/rust/blob/master/src/libstd/collections/hash/map.rs
+      https://github.com/rust-lang/rust/blob/master/src/libstd/collections/hash/set.rs
+      https://github.com/rust-lang/hashbrown/blob/master/src/map.rs
+      https://github.com/rust-lang/hashbrown/blob/master/src/set.rs
+      https://github.com/rust-lang/hashbrown/blob/master/src/raw/mod.rs
+  -->
+
+  <Type Name="std::collections::hash::map::HashMap&lt;*,*,*&gt;">
+    <DisplayString>{{ size={base.table.items} }}</DisplayString>
+    <Expand>
+      <Item Name="[size]">base.table.items</Item>
+      <Item Name="[capacity]">base.table.items + base.table.growth_left</Item>
+
+      <CustomListItems>
+        <Variable Name="i" InitialValue="0" />
+        <Variable Name="n" InitialValue="base.table.items" />
+        <Size>base.table.items</Size>
+        <Loop>
+          <Break Condition="n == 0" />
+          <If Condition="(base.table.ctrl.pointer[i] &amp; 0x80) == 0">
+            <!-- Bucket is populated -->
+            <Exec>n--</Exec>
+            <Item Name="{base.table.data.pointer[i].__0}">base.table.data.pointer[i].__1</Item>
+          </If>
+          <Exec>i++</Exec>
+        </Loop>
+      </CustomListItems>
+    </Expand>
+  </Type>
+
+  <Type Name="std::collections::hash::set::HashSet&lt;*,*&gt;">
+    <DisplayString>{{ size={map.base.table.items} }}</DisplayString>
+    <Expand>
+      <Item Name="[size]">map.base.table.items</Item>
+      <Item Name="[capacity]">map.base.table.items + map.base.table.growth_left</Item>
+
+      <CustomListItems>
+        <Variable Name="i" InitialValue="0" />
+        <Variable Name="n" InitialValue="map.base.table.items" />
+        <Size>map.base.table.items</Size>
+        <Loop>
+          <Break Condition="n == 0" />
+          <If Condition="(map.base.table.ctrl.pointer[i] &amp; 0x80) == 0">
+            <!-- Bucket is populated -->
+            <Exec>n--</Exec>
+            <Item>map.base.table.data.pointer[i].__0</Item>
+          </If>
+          <Exec>i++</Exec>
+        </Loop>
+      </CustomListItems>
+    </Expand>
+  </Type>
+
+  <Type Name="hashbrown::raw::RawTable&lt;*&gt;">
+    <!-- RawTable has a nice and simple layout.
+      items                     Number of *populated* values in the RawTable (less than the size of ctrl.pointer / data.pointer)
+      growth_left               Remaining capacity before growth
+      ctrl.pointer[i] & 0x80    Indicates the bucket is empty / should be skipped / doesn't count towards items.
+      data.pointer[i]           The (K,V) tuple, if not empty.
+    -->
+    <DisplayString>{{ size={items} }}</DisplayString>
+    <Expand>
+      <Item Name="[size]">items</Item>
+      <Item Name="[capacity]">items + growth_left</Item>
+
+      <CustomListItems>
+        <Variable Name="i" InitialValue="0" />
+        <Variable Name="n" InitialValue="items" />
+        <Size>items</Size>
+        <Loop>
+          <Break Condition="n == 0" />
+          <If Condition="(ctrl.pointer[i] &amp; 0x80) == 0">
+            <!-- Bucket is populated -->
+            <Exec>n--</Exec>
+            <Item>data.pointer[i]</Item>
+          </If>
+          <Exec>i++</Exec>
+        </Loop>
+      </CustomListItems>
+    </Expand>
+  </Type>
+</AutoVisualizer>
diff --git a/src/test/debuginfo/pretty-std-collections-hash.rs b/src/test/debuginfo/pretty-std-collections-hash.rs
new file mode 100644
index 00000000000..361b300f28c
--- /dev/null
+++ b/src/test/debuginfo/pretty-std-collections-hash.rs
@@ -0,0 +1,97 @@
+// cdb-only
+// compile-flags:-g
+
+// === CDB TESTS ==================================================================================
+
+// 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:    [capacity]       : [...]
+// cdb-check:    [[...]] [...]    : 0 [Type: unsigned __int64]
+// cdb-command: dx hash_set,d
+// cdb-check:    [[...]] [...]    : 1 [Type: unsigned __int64]
+// cdb-command: dx hash_set,d
+// cdb-check:    [[...]] [...]    : 2 [Type: unsigned __int64]
+// cdb-command: dx hash_set,d
+// cdb-check:    [[...]] [...]    : 3 [Type: unsigned __int64]
+// cdb-command: dx hash_set,d
+// cdb-check:    [[...]] [...]    : 4 [Type: unsigned __int64]
+// cdb-command: dx hash_set,d
+// cdb-check:    [[...]] [...]    : 5 [Type: unsigned __int64]
+// cdb-command: dx hash_set,d
+// cdb-check:    [[...]] [...]    : 6 [Type: unsigned __int64]
+// cdb-command: dx hash_set,d
+// cdb-check:    [[...]] [...]    : 7 [Type: unsigned __int64]
+// cdb-command: dx hash_set,d
+// cdb-check:    [[...]] [...]    : 8 [Type: unsigned __int64]
+// cdb-command: dx hash_set,d
+// cdb-check:    [[...]] [...]    : 9 [Type: unsigned __int64]
+// cdb-command: dx hash_set,d
+// cdb-check:    [[...]] [...]    : 10 [Type: unsigned __int64]
+// cdb-command: dx hash_set,d
+// cdb-check:    [[...]] [...]    : 11 [Type: unsigned __int64]
+// cdb-command: dx hash_set,d
+// cdb-check:    [[...]] [...]    : 12 [Type: unsigned __int64]
+// cdb-command: dx hash_set,d
+// cdb-check:    [[...]] [...]    : 13 [Type: unsigned __int64]
+// cdb-command: dx hash_set,d
+// cdb-check:    [[...]] [...]    : 14 [Type: unsigned __int64]
+
+// cdb-command: dx hash_map,d
+// cdb-check:hash_map,d [...] : { size=15 } [Type: [...]::HashMap<u64, u64, [...]>]
+// cdb-check:    [size]           : 15 [Type: [...]]
+// cdb-check:    [capacity]       : [...]
+// cdb-check:    ["0x0"]          : 0 [Type: unsigned __int64]
+// cdb-command: dx hash_map,d
+// cdb-check:    ["0x1"]          : 1 [Type: unsigned __int64]
+// cdb-command: dx hash_map,d
+// cdb-check:    ["0x2"]          : 2 [Type: unsigned __int64]
+// cdb-command: dx hash_map,d
+// cdb-check:    ["0x3"]          : 3 [Type: unsigned __int64]
+// cdb-command: dx hash_map,d
+// cdb-check:    ["0x4"]          : 4 [Type: unsigned __int64]
+// cdb-command: dx hash_map,d
+// cdb-check:    ["0x5"]          : 5 [Type: unsigned __int64]
+// cdb-command: dx hash_map,d
+// cdb-check:    ["0x6"]          : 6 [Type: unsigned __int64]
+// cdb-command: dx hash_map,d
+// cdb-check:    ["0x7"]          : 7 [Type: unsigned __int64]
+// cdb-command: dx hash_map,d
+// cdb-check:    ["0x8"]          : 8 [Type: unsigned __int64]
+// cdb-command: dx hash_map,d
+// cdb-check:    ["0x9"]          : 9 [Type: unsigned __int64]
+// cdb-command: dx hash_map,d
+// cdb-check:    ["0xa"]          : 10 [Type: unsigned __int64]
+// cdb-command: dx hash_map,d
+// cdb-check:    ["0xb"]          : 11 [Type: unsigned __int64]
+// cdb-command: dx hash_map,d
+// cdb-check:    ["0xc"]          : 12 [Type: unsigned __int64]
+// cdb-command: dx hash_map,d
+// cdb-check:    ["0xd"]          : 13 [Type: unsigned __int64]
+// cdb-command: dx hash_map,d
+// cdb-check:    ["0xe"]          : 14 [Type: unsigned __int64]
+
+#![allow(unused_variables)]
+use std::collections::HashSet;
+use std::collections::HashMap;
+
+
+fn main() {
+    // HashSet
+    let mut hash_set = HashSet::new();
+    for i in 0..15 {
+        hash_set.insert(i as u64);
+    }
+
+    // HashMap
+    let mut hash_map = HashMap::new();
+    for i in 0..15 {
+        hash_map.insert(i as u64, i as u64);
+    }
+
+    zzz(); // #break
+}
+
+fn zzz() { () }