nicolas/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Implement a safer bitcode upgrade for DISubprogram.

Browse Source 
The bitcode upgrade I added for DISubprogram in r266446 was based on the
assumption that the CU node for the subprogram was already materialized by the
time the DISubprogram is visited. This assumption may not hold true as future
versions of LLVM may decide to write out bitcode in a different order. This
patch corrects this by introducing a versioning bit next to the distinct flag to
unambiguously differentiate the new from the old record layouts.

Note for people stabilizing LLVM out-of-tree: This patch introduces a bitcode
incompatibility with llvm trunk revisions from r266446 — this commit. (But
D19987 will ensure that it degrades gracefully).

http://reviews.llvm.org/D20004
rdar://problem/26074194

llvm-svn: 268816
This commit is contained in:
Adrian Prantl
2016-05-06 22:53:06 +00:00
parent 22152acf7b
commit 85338cbdb6
2 changed files with 9 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
View File

@@ -1353,7 +1353,8 @@ void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
SmallVectorImpl<uint64_t> &Record,
unsigned Abbrev) {
Record.push_back(N->isDistinct());
uint64_t HasUnitFlag = 1 << 1;
Record.push_back(N->isDistinct() | HasUnitFlag);
Record.push_back(VE.getMetadataOrNullID(N->getScope()));
Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));