From 3e83f3ce4f5283f78e754eca566c42b90957c57b Mon Sep 17 00:00:00 2001
From: Mahesh Madhav <67384846+heshpdx@users.noreply.github.com>
Date: Fri, 18 Oct 2024 14:39:09 -0700
Subject: [PATCH] scons,misc: Portable debug flag generation (#1666)

Modifies union construction in the debug directory so output is more
amenable to alternative compilers. Verified that this change produces
code that builds with clang, gcc, msvc, nvhpc, aocc, icc, openxl, and
cray hpc.

These were the kinds of errors seen in MSVC, which this patch fixes.
```
debug/Decoder.hh(24): error C2461: 'gem5::debug::unions::Decoder': constructor syntax missing formal parameters
debug/Decoder.hh(31): error C7624: Type name 'gem5::debug::unions::Decoder' cannot appear on the right side of a class member access expression
```
---
 build_tools/debugflaghh.py | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/build_tools/debugflaghh.py b/build_tools/debugflaghh.py
index 1a4a379204..db322cb955 100644
--- a/build_tools/debugflaghh.py
+++ b/build_tools/debugflaghh.py
@@ -100,13 +100,16 @@ if components:
 inline union ${{args.name}}
 {
     ~${{args.name}}() {}
-    CompoundFlag ${{args.name}} = {
-        "${{args.name}}", "${{args.desc}}", {
+
+    CompoundFlag flag${{args.name}};
+
+    ${{args.name}}() : flag${{args.name}}("${{args.name}}", "${{args.desc}}",
+        {
             ${{",\\n            ".join(
                 f"(Flag *)&::gem5::debug::{flag}" for flag in components)}}
-        }
-    };
-} ${{args.name}};
+        }) {}
+
+} instance${{args.name}};
 """
     )
 else:
@@ -115,10 +118,11 @@ else:
 inline union ${{args.name}}
 {
     ~${{args.name}}() {}
-    SimpleFlag ${{args.name}} = {
-        "${{args.name}}", "${{args.desc}}", ${{"true" if fmt else "false"}}
-    };
-} ${{args.name}};
+    SimpleFlag flag${{args.name}};
+
+    ${{args.name}}() : flag${{args.name}}("${{args.name}}", "${{args.desc}}", ${{"true" if fmt else "false"}}) {}
+
+} instance${{args.name}};
 """
     )
 
@@ -127,7 +131,7 @@ code(
 } // namespace unions
 
 inline constexpr const auto& ${{args.name}} =
-    ::gem5::debug::unions::${{args.name}}.${{args.name}};
+    ::gem5::debug::unions::instance${{args.name}}.flag${{args.name}};
 
 } // namespace debug
 } // namespace gem5