llvm-project/lld
Teresa Johnson 3c4c205060 [WPD][lld] Test handling of vtable definition from shared libraries
Adds a lld test for a case that the handling added for dynamically
exported symbols in 1487747e99 already
fixes. Because isExportDynamic returns true when the symbol is
SharedKind with default visibility, it will treat as dynamically
exported and block devirtualization when the definition of a vtable
comes from a shared library. This is desireable as it is dangerous to
devirtualize in that case, since there could be hidden overrides in the
shared library. Typically that happens when the shared library header
contains available externally definitions, which applications can
override. An example is std::error_category, which is overridden in LLVM
and causing failures after a self build with WPD enabled, because
libstdc++ contains hidden overrides of the virtual base class methods.

The regular LTO case in the new test already worked, but there are
2 fixes in this patch needed for the index-only case and the hybrid
LTO case. For the index-only case, WPD should not simply ignore
available externally vtables. A follow on fix will be made to clang to
emit type metadata for those vtables, which the new test is modeling.
For the hybrid case, we need to ensure when the module is split that any
llvm.*used globals are cloned to the regular LTO split module so
available externally vtable definitions are not prematurely deleted.

Another follow on fix will add the equivalent gold test, which requires
a small fix to the plugin to treat symbols in dynamic libraries the same
way lld already is.

Differential Revision: https://reviews.llvm.org/D96721
2021-02-17 12:49:24 -08:00
..
COFF Revert "[PDB] Defer relocating .debug$S until commit time and parallelize it" 2021-01-28 13:17:27 -08:00
Common [lld/mac] Add --reproduce option 2020-11-30 08:40:21 -05:00
ELF fix comment typo to cycle bots 2021-02-17 15:29:39 -05:00
MachO [lld] Silence compiler warnings by removing always true/false comparisons 2021-02-17 08:16:02 +01:00
MinGW [LLD] [MinGW] Pass the --demangle and --no-demangle options to the COFF linker 2021-01-07 10:02:19 +02:00
cmake/modules lld: Let find_package(LLD) work 2020-05-14 09:59:53 -04:00
docs [ELF] Inspect -EL & -EB for OUTPUT_FORMAT(default, big, little) 2021-02-08 10:34:57 -08:00
include/lld fix comment typo to cycle bots 2021-02-17 11:49:23 -05:00
lib [MachO] Fix enum-int mismatch warning 2020-12-28 17:39:41 +01:00
test [WPD][lld] Test handling of vtable definition from shared libraries 2021-02-17 12:49:24 -08:00
tools/lld lld: Fix darwinnew symlink name added in e16c0a9a68 2020-11-24 11:06:51 -05:00
unittests Use INTERFACE_COMPILE_OPTIONS to disable -Wsuggest-override for any target that links to gtest 2020-07-27 08:37:01 -07:00
utils
wasm [WebAssembly][lld] Preassign table number 0 to indirect function table for MVP inputs 2021-02-12 20:20:19 +01:00
.clang-format
.clang-tidy [lld] Add .clang-tidy to customize readability-identifier-naming.{Member,Parameter,Variable}Case => camelBack 2020-03-09 08:26:41 -07:00
.gitignore
CMakeLists.txt Revert "[CMake] Actually require python 3.6 or greater" 2021-01-29 12:03:32 -08:00
CODE_OWNERS.TXT Add code owners of new MachO port 2020-09-02 19:32:12 -07:00
LICENSE.TXT
README.md [doc] Place sha256 in lld/README.md into backticks 2021-01-12 10:19:40 -08:00

README.md

LLVM Linker (lld)

This directory and its subdirectories contain source code for the LLVM Linker, a modular cross platform linker which is built as part of the LLVM compiler infrastructure project.

lld is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt.

Benchmarking

In order to make sure various developers can evaluate patches over the same tests, we create a collection of self contained programs.

It is hosted at https://s3-us-west-2.amazonaws.com/linker-tests/lld-speed-test.tar.xz

The current sha256 is 10eec685463d5a8bbf08d77f4ca96282161d396c65bd97dc99dbde644a31610f.