[llvm] [DebugInfo] Require non-null metadata fields in BitcodeWriter (PR #203181)

[Jiang Ning via llvm-commits]

https://github.com/JiangNingHX created https://github.com/llvm/llvm-project/pull/203181

Split out from #198441.
This makes BitcodeWriter assert non-null invariants for required debug metadata
fields while preserving the existing metadata-or-null bitcode encoding via
`getMetadataID(...) + 1`.

>From 67c53cd91627cae3f5bb253ccb13e6643adb16ff Mon Sep 17 00:00:00 2001
From: JiangNing <jiangninghx at foxmail.com>
Date: Thu, 11 Jun 2026 13:24:50 +0800
Subject: [PATCH] [DebugInfo] Require non-null debug metadata fields

Assert non-null invariants in BitcodeWriter for debug metadata fields
that are required by the textual IR parser, while preserving the existing
metadata-or-null bitcode encoding.
---
 llvm/lib/Bitcode/Writer/BitcodeWriter.cpp | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index f4857461ca58e..ed86e5aecdba6 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -2189,7 +2189,7 @@ void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
   if (Lang.hasVersionedName())
     Record.back() ^= (uint64_t(1) << 63);
 
-  Record.push_back(VE.getMetadataOrNullID(N->getFile()));
+  Record.push_back(VE.getMetadataID(N->getFile()) + 1);
   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
   Record.push_back(N->isOptimized());
   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
@@ -2251,7 +2251,7 @@ void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
                                               SmallVectorImpl<uint64_t> &Record,
                                               unsigned Abbrev) {
   Record.push_back(N->isDistinct());
-  Record.push_back(VE.getMetadataOrNullID(N->getScope()));
+  Record.push_back(VE.getMetadataID(N->getScope()) + 1);
   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
   Record.push_back(N->getLine());
   Record.push_back(N->getColumn());
@@ -2264,7 +2264,7 @@ void ModuleBitcodeWriter::writeDILexicalBlockFile(
     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
     unsigned Abbrev) {
   Record.push_back(N->isDistinct());
-  Record.push_back(VE.getMetadataOrNullID(N->getScope()));
+  Record.push_back(VE.getMetadataID(N->getScope()) + 1);
   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
   Record.push_back(N->getDiscriminator());
 
@@ -2421,7 +2421,7 @@ void ModuleBitcodeWriter::writeDILocalVariable(
   //   HasAlignment flag is true and Record[8] contains alignment value.
   const uint64_t HasAlignmentFlag = 1 << 1;
   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
-  Record.push_back(VE.getMetadataOrNullID(N->getScope()));
+  Record.push_back(VE.getMetadataID(N->getScope()) + 1);
   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
   Record.push_back(N->getLine());
@@ -2440,7 +2440,7 @@ void ModuleBitcodeWriter::writeDILabel(
     unsigned Abbrev) {
   uint64_t IsArtificialFlag = uint64_t(N->isArtificial()) << 1;
   Record.push_back((uint64_t)N->isDistinct() | IsArtificialFlag);
-  Record.push_back(VE.getMetadataOrNullID(N->getScope()));
+  Record.push_back(VE.getMetadataID(N->getScope()) + 1);
   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
   Record.push_back(N->getLine());