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fix: stop emitting `.debug_pubnames` and `.debug_pubtypes` A continuation of #94181. Fixes #48762 MCP can be found in <https://github.com/rust-lang/compiler-team/issues/688>. `.debug_pubnames` and `.debug_pubtypes` are poorly designed and people seldom use them. However, they take a considerable portion of size in the final binary. This tells LLVM stop emitting those sections on DWARFv4 or lower. DWARFv5 use `.debug_names` which is more concise in size and performant for name lookup. Some other no-really-useful personal notes: <details><summary>Details</summary> <p> ## Pepole saying they are not useful * https://github.com/rust-lang/rust/issues/48762 * https://rust-lang.zulipchat.com/#narrow/stream/317568-t-compiler.2Fwg-debugging/topic/investigating.20debuginfo.20size/near/342713604 * `DwarfCompileUnit::hasDwarfPubSections()` — https://github.com/llvm/llvm-project/blob/f633f325a1b808d33ca9653ed373353549ddcde6/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp#L1477-L1494 * clang default to no debug name table when no option provided — https://github.com/llvm/llvm-project/blob/f633f325a1b808d33ca9653ed373353549ddcde6/clang/lib/Frontend/CompilerInvocation.cpp#L1819-L1824 * GCC explicitly says GDB doesn't use pub sections (`TARGET_WANT_DEBUG_PUB_SECTIONS` only be true on Darwin) — https://github.com/gcc-mirror/gcc/blob/5d2a360f0a541646abb11efdbabc33c6a04de7ee/gcc/target.def#L6985-L6990 and https://github.com/bminor/binutils-gdb/blob/319b460545dc79280e2904dcc280057cf71fb753/gold/dwarf_reader.h#L424-L427 * Probably the only place that makes use of pub section in lldb — https://github.com/llvm/llvm-project/blob/725115d7bba2faf3d0c21442f4661dea77b8a77c/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp#L2117-L2135 * "The -gsplit-dwarf option requires -ggnu-pubnames." — https://github.com/gcc-mirror/gcc/blob/5d2a360f0a541646abb11efdbabc33c6a04de7ee/gcc/opts.cc#L1205 * LLVM: Always emit `.debug_names` with dwarf 5 for Apple platforms — https://reviews.llvm.org/D118754 </p> </details>
This directory currently contains some LLVM support code. This will generally be sent upstream to LLVM in time; for now it lives here. NOTE: the LLVM C++ ABI is subject to between-version breakage and must *never* be exposed to Rust. To allow for easy auditing of that, all Rust-exposed types must be typedef-ed as "LLVMXyz", or "LLVMRustXyz" if they were defined here. Functions that return a failure status and leave the error in the LLVM last error should return an LLVMRustResult rather than an int or anything to avoid confusion. When translating enums, add a single `Other` variant as the first one to allow for new variants to be added. It should abort when used as an input. All other types must not be typedef-ed as such.