[LLD] Add --lto-CGO[0-3] option

Allow controlling the CodeGenOpt::Level independent of the LTO
optimization level in LLD via new options for the COFF, ELF, MachO, and
wasm frontends to lld. Most are spelled as --lto-CGO[0-3], but COFF is
spelled as -opt:lldltocgo=[0-3].

See D57422 for discussion surrounding the issue of how to set the CG opt
level. The ultimate goal is to let each function control its CG opt
level, but until then the current default means it is impossible to
specify a CG opt level lower than 2 while using LTO. This option gives
the user a means to control it for as long as it is not handled on a
per-function basis.

Reviewed By: MaskRay, #lld-macho, int3

Differential Revision: https://reviews.llvm.org/D141970
This commit is contained in:
Scott Linder
2023-02-15 17:12:47 +00:00
parent 3cf7f22498
commit 45ee0a9afc
21 changed files with 174 additions and 17 deletions

View File

@@ -424,6 +424,14 @@ static void readConfigs(opt::InputArgList &args) {
config->importTable = args.hasArg(OPT_import_table);
config->importUndefined = args.hasArg(OPT_import_undefined);
config->ltoo = args::getInteger(args, OPT_lto_O, 2);
if (config->ltoo > 3)
error("invalid optimization level for LTO: " + Twine(config->ltoo));
unsigned ltoCgo =
args::getInteger(args, OPT_lto_CGO, args::getCGOptLevel(config->ltoo));
if (auto level = CodeGenOpt::getLevel(ltoCgo))
config->ltoCgo = *level;
else
error("invalid codegen optimization level for LTO: " + Twine(ltoCgo));
config->ltoPartitions = args::getInteger(args, OPT_lto_partitions, 1);
config->ltoDebugPassManager = args.hasArg(OPT_lto_debug_pass_manager);
config->mapFile = args.getLastArgValue(OPT_Map);
@@ -560,8 +568,6 @@ static void checkOptions(opt::InputArgList &args) {
error("--compress-relocations is incompatible with output debug"
" information. Please pass --strip-debug or --strip-all");
if (config->ltoo > 3)
error("invalid optimization level for LTO: " + Twine(config->ltoo));
if (config->ltoPartitions == 0)
error("--lto-partitions: number of threads must be > 0");
if (!get_threadpool_strategy(config->thinLTOJobs))