From 5023b1f257b245cf3f6d75143808a5fdcb2058f6 Mon Sep 17 00:00:00 2001
From: Chris Eibl <138194463+chris-eibl@users.noreply.github.com>
Date: Tue, 6 Oct 2026 08:36:02 +0200
Subject: [PATCH] gh-157789: Use compiler option ``-Og`` in case of clang-cl
 debug builds (GH-157791)

Use compiler option ``-Og`` in case of clang-cl debug builds on Windows to reduce stack usage.
(cherry picked from commit 9028df36bb9e2942b19164f6708f9cf8a55c5ce9)

Co-authored-by: Chris Eibl <138194463+chris-eibl@users.noreply.github.com>
---
 .../next/Windows/2026-09-19-13-18-48.gh-issue-157789.o6-rmo.rst | 2 ++
 PCbuild/pyproject-clangcl.props                                 | 1 +
 2 files changed, 3 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Windows/2026-09-19-13-18-48.gh-issue-157789.o6-rmo.rst

diff --git a/Misc/NEWS.d/next/Windows/2026-09-19-13-18-48.gh-issue-157789.o6-rmo.rst b/Misc/NEWS.d/next/Windows/2026-09-19-13-18-48.gh-issue-157789.o6-rmo.rst
new file mode 100644
index 000000000000000..f7f998b9eced36a
--- /dev/null
+++ b/Misc/NEWS.d/next/Windows/2026-09-19-13-18-48.gh-issue-157789.o6-rmo.rst
@@ -0,0 +1,2 @@
+Use compiler option ``-Og`` in case of clang-cl debug builds on Windows to
+reduce stack usage. Patch by Chris Eibl.
diff --git a/PCbuild/pyproject-clangcl.props b/PCbuild/pyproject-clangcl.props
index 70a81ca7da306c3..14843f18823ca9b 100644
--- a/PCbuild/pyproject-clangcl.props
+++ b/PCbuild/pyproject-clangcl.props
@@ -50,6 +50,7 @@
       <AdditionalOptions Condition="'$(Platform)' == 'Win32'">-m32 %(AdditionalOptions)</AdditionalOptions>
       <AdditionalOptions Condition="'$(Platform)' == 'x64'">-m64 %(AdditionalOptions)</AdditionalOptions>
       <AdditionalOptions Condition="$(Configuration) != 'Debug'">-flto=thin %(AdditionalOptions)</AdditionalOptions>
+      <AdditionalOptions Condition="$(Configuration) == 'Debug'">%(AdditionalOptions) -Xclang -Og</AdditionalOptions>
       <AdditionalOptions Condition="$(SupportPGO) and $(Configuration) == 'PGInstrument'">-fprofile-instr-generate=$(_CLANG_PROFILE_PATH)$(TargetName)_%m.profraw %(AdditionalOptions)</AdditionalOptions>
       <AdditionalOptions Condition="$(SupportPGO) and $(Configuration) == 'PGUpdate'">-fprofile-instr-use=$(OutDir)instrumented\profdata.profdata -Wno-profile-instr-unprofiled %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>