llvm-6502/lib/Bitcode/Writer
Duncan P. N. Exon Smith ea8cbe9782 Bitcode: Stop assuming non-null fields
When writing the bitcode serialization for the new debug info hierarchy,
I assumed two fields would never be null.

Drop that assumption, since it's brittle (and crashes the
`BitcodeWriter` if wrong), and is a check better left for the verifier
anyway.  (No need for a bitcode upgrade here, since the new hierarchy is
still not in place.)

The fields in question are `MDCompileUnit::getFile()` and
`MDDerivedType::getBaseType()`, the latter of which isn't null in
test/Transforms/Mem2Reg/ConvertDebugInfo2.ll (see !14, a pointer to
nothing).  While the testcase might have bitrotted, there's no reason
for the bitcode format to rely on non-null for metadata operands.

This also fixes a bug in `AsmWriter` where if the `file:` is null it
isn't emitted (caught by the double-round trip in the testcase I'm
adding) -- this is a required field in `LLParser`.

I'll circle back to ConvertDebugInfo2.  Once the specialized nodes are
in place, I'll be trying to turn the debug info verifier back on by
default (in the newer module pass form committed r206300) and throwing
more logic in there.  If the testcase has bitrotted (as opposed to me
not understanding the schema correctly) I'll fix it then.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229960 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-20 03:17:58 +00:00
..
BitcodeWriter.cpp Bitcode: Stop assuming non-null fields 2015-02-20 03:17:58 +00:00
BitcodeWriterPass.cpp [PM] Switch the new pass manager to use a reference-based API for IR 2015-01-05 02:47:05 +00:00
BitWriter.cpp Introduce LLVMWriteBitcodeToMemoryBuffer C API function. 2014-10-14 00:30:59 +00:00
CMakeLists.txt
LLVMBuild.txt
Makefile
ValueEnumerator.cpp IR: Assembly and bitcode for GenericDebugNode 2015-02-03 21:54:14 +00:00
ValueEnumerator.h Removing LLVM_DELETED_FUNCTION, as MSVC 2012 was the last reason for requiring the macro. NFC; LLVM edition. 2015-02-15 22:54:22 +00:00