Apologies for the large change, I looked for ways to break this up and all of the ones I saw added real complexity. This change focuses on the option's prefixed names and the array of prefixes. These are present in every option and the dominant source of dynamic relocations for PIE or PIC users of LLVM and Clang tooling. In some cases, 100s or 1000s of them for the Clang driver which has a huge number of options. This PR addresses this by building a string table and a prefixes table that can be referenced with indices rather than pointers that require dynamic relocations. This removes almost 7k dynmaic relocations from the `clang` binary, roughly 8% of the remaining dynmaic relocations outside of vtables. For busy-boxing use cases where many different option tables are linked into the same binary, the savings add up a bit more. The string table is a straightforward mechanism, but the prefixes required some subtlety. They are encoded in a Pascal-string fashion with a size followed by a sequence of offsets. This works relatively well for the small realistic prefixes arrays in use. Lots of code has to change in order to land this though: both all the option library code has to be updated to use the string table and prefixes table, and all the users of the options library have to be updated to correctly instantiate the objects. Some follow-up patches in the works to provide an abstraction for this style of code, and to start using the same technique for some of the other strings here now that the infrastructure is in place.
Move common functions shared by TableGen Option Emitter and Options library to Support: - Move `StrCmpOptionName` and base it on the existing version in OptTable.cpp, with an additional mode to control fall back to case insensitive comparison. - Add `StrCmpOptionPrefixes` to compare prefixes and use zip() to iterate through lists of prefixes. - Rename `CompareOptionRecords` to less ambiguous name `IsOptionRecordLess`. - Merge 2 back-to-back ifs with same condition in `IsOptionRecordLess`. Fixes https://github.com/llvm/llvm-project/issues/107723
Arg::print calls Option::print and Option::print calls itself recursively. Add a flag so we can avoid seemingly random breaks in the print output of an argument list. No tests since this only affects debug output.
Replace multiple strlen calls with a StringRef constructor and a StringRef::size call. Differential Revision: https://reviews.llvm.org/D146394
Differential Revision: https://reviews.llvm.org/D146394
This avoids recomputing string length that is already known at compile time. It has a slight impact on preprocessing / compile time, see https://llvm-compile-time-tracker.com/compare.php?from=3f36d2d579d8b0e8824d9dd99bfa79f456858f88&to=e49640c507ddc6615b5e503144301c8e41f8f434&stat=instructions:u This a recommit of e953ae5bbc313fd0cc980ce021d487e5b5199ea4 and the subsequent fixes caa713559bd38f337d7d35de35686775e8fb5175 and 06b90e2e9c991e211fecc97948e533320a825470. The above patchset caused some version of GCC to take eons to compile clang/lib/Basic/Targets/AArch64.cpp, as spotted in aa171833ab0017d9732e82b8682c9848ab25ff9e. The fix is to make BuiltinInfo tables a compilation unit static variable, instead of a private static variable. Differential Revision: https://reviews.llvm.org/D139881
Revert "Fix lldb option handling since e953ae5bbc313fd0cc980ce021d487e5b5199ea4 (part 2)" Revert "Fix lldb option handling since e953ae5bbc313fd0cc980ce021d487e5b5199ea4" GCC build hangs on this bot https://lab.llvm.org/buildbot/#/builders/37/builds/19104 compiling CMakeFiles/obj.clangBasic.dir/Targets/AArch64.cpp.d The bot uses GNU 11.3.0, but I can reproduce locally with gcc (Debian 12.2.0-3) 12.2.0. This reverts commit caa713559bd38f337d7d35de35686775e8fb5175. This reverts commit 06b90e2e9c991e211fecc97948e533320a825470. This reverts commit e953ae5bbc313fd0cc980ce021d487e5b5199ea4.
This avoids recomputing string length that is already known at compile time. It has a slight impact on preprocessing / compile time, see https://llvm-compile-time-tracker.com/compare.php?from=3f36d2d579d8b0e8824d9dd99bfa79f456858f88&to=e49640c507ddc6615b5e503144301c8e41f8f434&stat=instructions:u This is a recommit of 719d98dfa841c522d8d452f0685e503538415a53 that into account a GGC issue (probably https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92181) when dealing with intiailizer_list and constant expressions. Workaround this by avoiding initializer list, at the expense of a temporary plain old array. Differential Revision: https://reviews.llvm.org/D139881
There are still remaining issues with GCC 12, see for instance https://lab.llvm.org/buildbot/#/builders/93/builds/12669 This reverts commit 5ce4e92264102de21760c94db9166afe8f71fcf6.
This avoids recomputing string length that is already known at compile time. It has a slight impact on preprocessing / compile time, see https://llvm-compile-time-tracker.com/compare.php?from=3f36d2d579d8b0e8824d9dd99bfa79f456858f88&to=e49640c507ddc6615b5e503144301c8e41f8f434&stat=instructions:u This is a recommit of 719d98dfa841c522d8d452f0685e503538415a53 with a change to llvm/utils/TableGen/OptParserEmitter.cpp to cope with GCC bug https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108158 Differential Revision: https://reviews.llvm.org/D139881