llvm-project/llvm/unittests/DebugInfo/PDB
Nico Weber e577be4ed1 [PDB] Fix hash function used to write /src/headerblock
lld-link used to write PDB files that DIA couldn't recover natvis
files from if:

- The global strings table was > 64kiB
- There were at least 3 natvis files

The cause was that the hash function for the /src/headerblock stream
was incorrect: It needs to be truncated to 16 bit.

If the global strings table was <= 64kiB, truncating to 16 bit is a
no-op, so this wasn't needed for small programs.

If there are only 1 or 2 natvis files, then the growth strategy in
HashTable::grow() would mean the hash table would have 2 buckets (for 1
natvis file) or 4 buckets (for 4 natvis files), and since the hash
function is used modulo number of buckets, and since 2 and 4 divide
0x10000, the missing `% 0x10000` is a no-op there too. For 3 natvis
files, the hash table grows to 6 buckets, which has a factor that's not
common with 0x10000 and the difference starts to matter.

Fixes PR41626.

Differential Revision: https://reviews.llvm.org/D61277

llvm-svn: 359515
2019-04-29 23:09:35 +00:00
..
Inputs [PDB] Refactor the PDB symbol classes to fix a reuse bug. 2018-09-05 23:30:38 +00:00
CMakeLists.txt Introduce explicit add_unittest_with_input_files target for tests that use llvm::getInputFileDirectory() 2018-09-14 17:34:46 +00:00
HashTableTest.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
NativeSymbolReuseTest.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
PDBApiTest.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
StringTableBuilderTest.cpp [PDB] Fix hash function used to write /src/headerblock 2019-04-29 23:09:35 +00:00