If a header map file is corrupt, the strings in the string table may not
be null-terminated. The logic here previously relied on `MemoryBuffer`
always being null-terminated, but this isn't actually guaranteed by the
class AFAICT. Moreover, we're seeing a lot of crash traces at calls to
`strlen()` inside of `lookupFilename()`, so something is going wrong
there.
Instead, use `strnlen()` to get the length, and check for corruption.
Also remove code paths that could call `StringRef(nullptr)`. r261459
made these rather obvious (although they'd been there all along).
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@261461 91177308-0d34-0410-b5e6-96231b3b80d8
Add a simple test for `HeaderMap::lookupFileName()`. I'm planning to
add better error checking in a moment, and I'll add more tests like this
then.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@261455 91177308-0d34-0410-b5e6-96231b3b80d8
Check up front whether the header map buffer has space for all of its
declared buckets.
There was already a check in `getBucket()`, but it had UB (comparing
pointers that were outside of objects in the error path) and was
insufficient (only checking for a single byte of the relevant bucket).
I fixed the check, moved it to `checkHeader()`, and left a fixed version
behind as an assertion.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@261449 91177308-0d34-0410-b5e6-96231b3b80d8
If the number of buckets is not a power of two, immediately recognize
the header map as corrupt, rather than waiting for the first lookup. I
converted the later check to an assert.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@261448 91177308-0d34-0410-b5e6-96231b3b80d8
Split the implementation of `HeaderMap` into `HeaderMapImpl` so that we
can write unit tests that don't depend on the `FileManager`, and then
write a few tests that cover the types of corrupt header maps already
detected.
This also moves type and constant definitions from HeaderMap.cpp to
HeaderMapTypes.h so that the test can access them.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@261446 91177308-0d34-0410-b5e6-96231b3b80d8
Duncan P. N. Exon Smith