Begin adding experimental support for preserving use-list ordering of bitcode
files. First, add a new block USELIST_BLOCK to the bitcode format. This is
where USELIST_CODE_ENTRYs will be stored. The format of the USELIST_CODE_ENTRYs
have not yet been defined. Add support in the BitcodeReader for parsing the
USELIST_BLOCK.
Part of rdar://9860654 and PR5680.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146078 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index 3682e6d..d584015 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -1287,6 +1287,50 @@
return false;
}
+bool BitcodeReader::ParseUseLists() {
+ if (Stream.EnterSubBlock(bitc::USELIST_BLOCK_ID))
+ return Error("Malformed block record");
+
+ SmallVector<uint64_t, 64> Record;
+
+ // Read all the records.
+ while (1) {
+ unsigned Code = Stream.ReadCode();
+ if (Code == bitc::END_BLOCK) {
+ if (Stream.ReadBlockEnd())
+ return Error("Error at end of use-list table block");
+ return false;
+ }
+
+ if (Code == bitc::ENTER_SUBBLOCK) {
+ // No known subblocks, always skip them.
+ Stream.ReadSubBlockID();
+ if (Stream.SkipBlock())
+ return Error("Malformed block record");
+ continue;
+ }
+
+ if (Code == bitc::DEFINE_ABBREV) {
+ Stream.ReadAbbrevRecord();
+ continue;
+ }
+
+ // Read a use list record.
+ Record.clear();
+ switch (Stream.ReadRecord(Code, Record)) {
+ default: // Default behavior: unknown type.
+ break;
+ case bitc::USELIST_CODE_ENTRY: { // USELIST_CODE_ENTRY: TBD.
+ unsigned RecordLength = Record.size();
+ if (RecordLength < 1)
+ return Error ("Invalid UseList reader!");
+ UseListRecords.push_back(Record);
+ break;
+ }
+ }
+ }
+}
+
/// RememberAndSkipFunctionBody - When we see the block for a function body,
/// remember where it is and then skip it. This lets us lazily deserialize the
/// functions.
@@ -1393,6 +1437,10 @@
if (RememberAndSkipFunctionBody())
return true;
break;
+ case bitc::USELIST_BLOCK_ID:
+ if (ParseUseLists())
+ return true;
+ break;
}
continue;
}
@@ -2746,6 +2794,9 @@
return 0;
}
+ // TODO: Restore the use-lists to the in-memory state when the bitcode was
+ // written. We must defer until the Module has been fully materialized.
+
return M;
}