fixes #25338; Switch default mangling back to cpp (#25343)

fixes #25338

(cherry picked from commit ed8e5a7754)

changelog.md

@@ -27,7 +27,7 @@ errors.
 
 - With `-d:nimPreviewDuplicateModuleError`, importing two modules that share the same name becomes a compile-time error. This includes importing the same module more than once. Use `import foo as foo1` (or other aliases) to avoid collisions.
 
-- Adds the switch `--mangle:nim|cpp`, which selects `nim` or `cpp` style name mangling when used with `debuginfo` on, defaults to `nim`. The default is changed from `cpp` to `nim`.
+- Adds the switch `--mangle:nim|cpp`, which selects `nim` or `cpp` style name mangling when used with `debuginfo` on, defaults to `cpp`.
 
 - The second parameter of `succ`, `pred`, `inc`, and `dec` in `system` now accepts `SomeInteger` (previously `Ordinal`).
 

compiler/options.nim

@@ -509,7 +509,7 @@ const
     optHints, optStackTrace, optLineTrace, # consider adding `optStackTraceMsgs`
     optTrMacros, optStyleCheck, optCursorInference}
   DefaultGlobalOptions* = {optThreadAnalysis, optExcessiveStackTrace,
-    optJsBigInt64}
+    optJsBigInt64, optItaniumMangle}
 
 proc getSrcTimestamp(): DateTime =
   try:

doc/advopt.txt

@@ -90,7 +90,7 @@ Advanced options:
   --os:SYMBOL               set the target operating system (cross-compilation)
   --cpu:SYMBOL              set the target processor (cross-compilation)
   --debuginfo:on|off        enables debug information
-  --mangle:nim|cpp          selects `nim` or `cpp` style name mangling, defaults to `nim`
+  --mangle:nim|cpp          selects `nim` or `cpp` style name mangling, defaults to `cpp`
   -t, --passC:OPTION        pass an option to the C compiler
   -l, --passL:OPTION        pass an option to the linker
   --cc:SYMBOL               specify the C compiler

tests/codegen/titaniummangle.nim

@@ -1,6 +1,6 @@
 discard """
   targets: "c cpp"
-  matrix: "--debugger:native --mangle:cpp"
+  matrix: "--debugger:native --mangle:cpp; --debugger:native"
   ccodecheck: "'_ZN14titaniummangle8testFuncE'"
   ccodecheck: "'_ZN14titaniummangle8testFuncE6stringN14titaniummangle3FooE'"
   ccodecheck: "'_ZN14titaniummangle8testFuncE3int7varargsI6stringE'"