[lld-macho] Parallelize scanning the symbol tables in export/unexport-ing.
(Split from D113167)
Benchmarking on one of our large apps which exports a few thousands symbols,
this showed an improvement of ~17%.
x ./LLD_no_parallel.txt
+ ./LLD_with_parallel.txt
N Min Max Median Avg Stddev
x 10 84.01 89.41 88.64 87.693 1.7424061
+ 10 71.9 74.29 72.63 72.753 0.77734663
Difference at 95.0% confidence
-14.94 +/- 1.26763
-17.0367% +/- 1.44553%
(Student's t, pooled s = 1.34912)
(wallclock)
Differential Revision: https://reviews.llvm.org/D113820
GitOrigin-RevId: ad932320d89684e23f7952e54bc90c96598db1a3
diff --git a/MachO/Driver.cpp b/MachO/Driver.cpp
index 82914c3..ceaefed 100644
--- a/MachO/Driver.cpp
+++ b/MachO/Driver.cpp
@@ -1462,7 +1462,7 @@
createSyntheticSymbols();
if (!config->exportedSymbols.empty()) {
- for (Symbol *sym : symtab->getSymbols()) {
+ parallelForEach(symtab->getSymbols(), [](Symbol *sym) {
if (auto *defined = dyn_cast<Defined>(sym)) {
StringRef symbolName = defined->getName();
if (config->exportedSymbols.match(symbolName)) {
@@ -1474,12 +1474,13 @@
defined->privateExtern = true;
}
}
- }
+ });
} else if (!config->unexportedSymbols.empty()) {
- for (Symbol *sym : symtab->getSymbols())
+ parallelForEach(symtab->getSymbols(), [](Symbol *sym) {
if (auto *defined = dyn_cast<Defined>(sym))
if (config->unexportedSymbols.match(defined->getName()))
defined->privateExtern = true;
+ });
}
for (const Arg *arg : args.filtered(OPT_sectcreate)) {
