From 4323177f07e170a10b67d0cb194a254b00f587be Mon Sep 17 00:00:00 2001
From: Jonathan Emmett <joemmett@microsoft.com>
Date: Fri, 26 Mar 2021 09:59:01 -0400
Subject: [PATCH] Improve coroutine_handle visualization with intrinsics

This improves the visualization of `std::coroutine_handle`. These are
implemented by native visualization code and will require an updated
Visual Studio to work. All take the frame pointer `_Ptr` as an argument.

 * `primary_function` returns the address of the user coroutine function.
 This is used in the display name of the coroutine_handle to indicate
 with which coroutine it is associated instead of the compiler-generated
 resume function.
 * `suspend_point` returns the suspend point index at which the coroutine
 is currently suspended. The natvis rules will display friendly names
 for the special suspend points for initial (1) and final (0, -1) suspend.
 * `suspend_point_line` returns the line number of the current suspend
 point. This requires additional debugging info in the .PDB which is
 not present in the initial compiler releases with standard coroutine
 support. The natvis rules will omit the line number if it's not available.
---
 stl/debugger/STL.natvis | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/stl/debugger/STL.natvis b/stl/debugger/STL.natvis
index 008bb6ddb97..aed5ae4210d 100644
--- a/stl/debugger/STL.natvis
+++ b/stl/debugger/STL.natvis
@@ -1599,7 +1599,7 @@ SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
     </Expand>
   </Type>
 
-  <!-- Visualizer for standard coroutines (/std:c++20) -->
+  <!-- Visualizer for standard coroutines (/std:c++20, /await:strict) -->
   <Type Name="std::coroutine_handle&lt;*&gt;" IncludeView="ViewPromise">
     <Expand>
       <Item Name="Promise">*reinterpret_cast&lt;$T1 *&gt;(reinterpret_cast&lt;char*&gt;(_Ptr) + 2*sizeof(void*))</Item>
@@ -1607,8 +1607,20 @@ SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   </Type>
 
   <Type Name="std::coroutine_handle&lt;*&gt;">
-    <DisplayString Condition="*reinterpret_cast&lt;void(__cdecl**)(void*)&gt;(_Ptr) != nullptr">{*reinterpret_cast&lt;void(__cdecl**)(void*)&gt;(_Ptr),na}</DisplayString>
-    <DisplayString Condition="*reinterpret_cast&lt;void(__cdecl**)(void*)&gt;(_Ptr) == nullptr">{*(reinterpret_cast&lt;void(__cdecl**)(void*)&gt;(_Ptr) + 1),na}</DisplayString>
+    <Intrinsic Name="suspend_point" SourceId="FA88A41F-A641-47C8-8373-4889B7564FCF" LanguageId="3A12D0B7-C26C-11D0-B442-00A0244A1DD2" Id="1" ReturnType="int">
+        <Parameter Type="void*" />
+    </Intrinsic>
+    <Intrinsic Name="suspend_point_line" SourceId="FA88A41F-A641-47C8-8373-4889B7564FCF" LanguageId="3A12D0B7-C26C-11D0-B442-00A0244A1DD2" Id="2" ReturnType="unsigned int">
+        <Parameter Type="void*" />
+    </Intrinsic>
+    <Intrinsic Name="primary_function" SourceId="FA88A41F-A641-47C8-8373-4889B7564FCF" LanguageId="3A12D0B7-C26C-11D0-B442-00A0244A1DD2" Id="3" ReturnType="void*">
+        <Parameter Type="void*" />
+    </Intrinsic>
+    <DisplayString Condition="_Ptr == nullptr">empty</DisplayString>
+    <DisplayString Condition="_Ptr != nullptr &amp;&amp; suspend_point(_Ptr) &lt; 1">{primary_function(_Ptr),na} #final suspend</DisplayString>
+    <DisplayString Condition="_Ptr != nullptr &amp;&amp; suspend_point(_Ptr) == 1">{primary_function(_Ptr),na} #initial suspend</DisplayString>
+    <DisplayString Condition="_Ptr != nullptr &amp;&amp; suspend_point(_Ptr) &gt; 1 &amp;&amp; suspend_point_line(_Ptr) == 0">{primary_function(_Ptr),na} #suspend point {suspend_point(_Ptr)}</DisplayString>
+    <DisplayString Condition="_Ptr != nullptr &amp;&amp; suspend_point(_Ptr) &gt; 1 &amp;&amp; suspend_point_line(_Ptr) != 0">{primary_function(_Ptr),na} #suspend point {suspend_point(_Ptr)}, line {suspend_point_line(_Ptr)}</DisplayString>
     <Expand>
       <ExpandedItem>this,view(ViewPromise)</ExpandedItem>
     </Expand>