[llvm] Implement a custom stream for LDBG macro to handle newlines (PR #150750)

[Mehdi Amini via llvm-commits]

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@@ -30,37 +30,95 @@ namespace llvm {
 #define DEBUGLOG_WITH_STREAM_AND_TYPE(STREAM, TYPE)                            \
   for (bool _c = (::llvm::DebugFlag && ::llvm::isCurrentDebugType(TYPE)); _c;  \
        _c = false)                                                             \
-  ::llvm::impl::LogWithNewline(TYPE, __SHORT_FILE__, __LINE__, (STREAM))
+  ::llvm::impl::LogWithNewline(TYPE, __SHORT_FILE__, __LINE__, (STREAM))       \
+      .stream()
 #else
 #define DEBUGLOG_WITH_STREAM_AND_TYPE(STREAM, TYPE)                            \
   for (bool _c = (::llvm::DebugFlag && ::llvm::isCurrentDebugType(TYPE)); _c;  \
        _c = false)                                                             \
-  ::llvm::impl::LogWithNewline(TYPE, __FILE__, __LINE__, (STREAM))
+  ::llvm::impl::LogWithNewline(TYPE, __FILE__, __LINE__, (STREAM)).stream()
 #endif
 
 namespace impl {
-class LogWithNewline {
+
+/// A raw_ostream that tracks `\n` and print the prefix.
+class LLVM_ABI raw_ldbg_ostream final : public raw_ostream {
+  std::string Prefix;
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joker-eph wrote:

Done! PTAL.

https://github.com/llvm/llvm-project/pull/150750