[llvm-branch-commits] [Remarks] Restructure bitstream remarks to be fully standalone (PR #156715)

[Jon Roelofs via llvm-branch-commits]

================
@@ -256,14 +251,57 @@ Error BitstreamParserHelper::parseBlockInfoBlock() {
   return Error::success();
 }
 
-Error BitstreamParserHelper::advanceToMetaBlock() {
+Error BitstreamParserHelper::parseMeta() {
   if (Error E = expectMagic())
     return E;
   if (Error E = parseBlockInfoBlock())
     return E;
+
+  // Parse early meta block
+  if (Error E = MetaHelper.expectBlock())
+    return E;
+  if (Error E = MetaHelper.parseBlock())
+    return E;
+
+  // Skip all Remarks blocks
+  while (!Stream.AtEndOfStream()) {
+    auto MaybeBlockID = expectSubBlock(Stream);
+    if (!MaybeBlockID)
+      return MaybeBlockID.takeError();
+    if (*MaybeBlockID == META_BLOCK_ID)
+      break;
+    if (*MaybeBlockID != REMARK_BLOCK_ID)
+      return error("Unexpected block between meta blocks.");
+    // Remember first remark block
+    if (!RemarkStartBitPos)
+      RemarkStartBitPos = Stream.GetCurrentBitNo();
+    if (Error E = Stream.SkipBlock())
+      return E;
+  }
+
+  // Late meta block is optional if there are no remarks.
+  if (Stream.AtEndOfStream())
+    return Error::success();
+
+  // Parse late meta block
+  if (Error E = MetaHelper.parseBlock())
+    return E;
   return Error::success();
 }
 
+Error BitstreamParserHelper::parseRemark() {
+  if (RemarkStartBitPos) {
+    RemarkStartBitPos.reset();
+  } else {
----------------
jroelofs wrote:

```suggestion
  if (RemarkStartBitPos)
    RemarkStartBitPos.reset();
  else {
```

https://github.com/llvm/llvm-project/pull/156715