[llvm] Introduce LDBG_OS() macro as a variant of LDBG() (PR #157194)

[Jacques Pienaar via llvm-commits]

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@@ -19,52 +19,57 @@
 namespace llvm {
 #ifndef NDEBUG
 
-// LDBG() is a macro that can be used as a raw_ostream for debugging.
-// It will stream the output to the dbgs() stream, with a prefix of the
-// debug type and the file and line number. A trailing newline is added to the
-// output automatically. If the streamed content contains a newline, the prefix
-// is added to each beginning of a new line. Nothing is printed if the debug
-// output is not enabled or the debug type does not match.
-//
-// E.g.,
-//   LDBG() << "Bitset contains: " << Bitset;
-// is somehow equivalent to
-//   LLVM_DEBUG(dbgs() << "[" << DEBUG_TYPE << "] " << __FILE__ << ":" <<
-//   __LINE__ << " "
-//              << "Bitset contains: " << Bitset << "\n");
-//
+/// LDBG() is a macro that can be used as a raw_ostream for debugging.
+/// It will stream the output to the dbgs() stream, with a prefix of the
+/// debug type and the file and line number. A trailing newline is added to the
+/// output automatically. If the streamed content contains a newline, the prefix
+/// is added to each beginning of a new line. Nothing is printed if the debug
+/// output is not enabled or the debug type does not match.
+///
+/// E.g.,
+///   LDBG() << "Bitset contains: " << Bitset;
+/// is somehow equivalent to
+///   LLVM_DEBUG(dbgs() << "[" << DEBUG_TYPE << "] " << __FILE__ << ":" <<
+///   __LINE__ << " "
+///              << "Bitset contains: " << Bitset << "\n");
+///
 // An optional `level` argument can be provided to control the verbosity of the
-// output. The default level is 1, and is in increasing level of verbosity.
-//
-// The `level` argument can be a literal integer, or a macro that evaluates to
-// an integer.
-//
-// An optional `type` argument can be provided to control the debug type. The
-// default type is DEBUG_TYPE. The `type` argument can be a literal string, or a
-// macro that evaluates to a string.
+/// output. The default level is 1, and is in increasing level of verbosity.
+///
+/// The `level` argument can be a literal integer, or a macro that evaluates to
+/// an integer.
+///
+/// An optional `type` argument can be provided to control the debug type. The
+/// default type is DEBUG_TYPE. The `type` argument can be a literal string, or
+/// a macro that evaluates to a string.
+///
+/// E.g.,
+///   LDBG(2) << "Bitset contains: " << Bitset;
+///   LDBG("debug_type") << "Bitset contains: " << Bitset;
+///   LDBG(2, "debug_type") << "Bitset contains: " << Bitset;
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jpienaar wrote:

Oh, I didn't realize both orders of level and type worked.

https://github.com/llvm/llvm-project/pull/157194