[lld] 12607f5 - [ELF] Cache compute_thread_count. NFC

[Fangrui Song via llvm-commits]

Author: Fangrui Song
Date: 2022-09-12T19:09:08-07:00
New Revision: 12607f57da9aa990eb9ec3f671214058d86ab1b1

URL: https://github.com/llvm/llvm-project/commit/12607f57da9aa990eb9ec3f671214058d86ab1b1
DIFF: https://github.com/llvm/llvm-project/commit/12607f57da9aa990eb9ec3f671214058d86ab1b1.diff

LOG: [ELF] Cache compute_thread_count. NFC

Added: 
    

Modified: 
    lld/ELF/Config.h
    lld/ELF/Driver.cpp
    lld/ELF/SyntheticSections.cpp
    lld/ELF/Writer.cpp

Removed: 
    


################################################################################
diff  --git a/lld/ELF/Config.h b/lld/ELF/Config.h
index 26a6d63818957..fcba9216aa966 100644
--- a/lld/ELF/Config.h
+++ b/lld/ELF/Config.h
@@ -364,6 +364,8 @@ struct Configuration {
   // this means to map the primary and thread stacks as PROT_MTE. Note: This is
   // not supported on Android 11 & 12.
   bool androidMemtagStack;
+
+  unsigned threadCount;
 };
 
 // The only instance of Configuration struct.

diff  --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
index 369ef02947177..85d1fb4a749ce 100644
--- a/lld/ELF/Driver.cpp
+++ b/lld/ELF/Driver.cpp
@@ -1363,6 +1363,7 @@ static void readConfigs(opt::InputArgList &args) {
   }
   if (auto *arg = args.getLastArg(OPT_thinlto_jobs))
     config->thinLTOJobs = arg->getValue();
+  config->threadCount = parallel::strategy.compute_thread_count();
 
   if (config->ltoo > 3)
     error("invalid optimization level for LTO: " + Twine(config->ltoo));

diff  --git a/lld/ELF/SyntheticSections.cpp b/lld/ELF/SyntheticSections.cpp
index 291c925cfb044..ce041c2053ed9 100644
--- a/lld/ELF/SyntheticSections.cpp
+++ b/lld/ELF/SyntheticSections.cpp
@@ -2769,10 +2769,8 @@ createSymbols(
   // of millions for very large executables, so we use multi-threading to
   // speed it up.
   constexpr size_t numShards = 32;
-  size_t concurrency = PowerOf2Floor(
-      std::min<size_t>(hardware_concurrency(parallel::strategy.ThreadsRequested)
-                           .compute_thread_count(),
-                       numShards));
+  const size_t concurrency =
+      PowerOf2Floor(std::min<size_t>(config->threadCount, numShards));
 
   // A sharded map to uniquify symbols by name.
   auto map =
@@ -3257,10 +3255,8 @@ void MergeNoTailSection::finalizeContents() {
 
   // Concurrency level. Must be a power of 2 to avoid expensive modulo
   // operations in the following tight loop.
-  size_t concurrency = PowerOf2Floor(
-      std::min<size_t>(hardware_concurrency(parallel::strategy.ThreadsRequested)
-                           .compute_thread_count(),
-                       numShards));
+  const size_t concurrency =
+      PowerOf2Floor(std::min<size_t>(config->threadCount, numShards));
 
   // Add section pieces to the builders.
   parallelFor(0, concurrency, [&](size_t threadId) {

diff  --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp
index 9124961a5089f..cc8742e652b64 100644
--- a/lld/ELF/Writer.cpp
+++ b/lld/ELF/Writer.cpp
@@ -317,7 +317,7 @@ template <class ELFT> void elf::createSyntheticSections() {
 
   StringRef relaDynName = config->isRela ? ".rela.dyn" : ".rel.dyn";
 
-  const unsigned threadCount = parallel::strategy.compute_thread_count();
+  const unsigned threadCount = config->threadCount;
   for (Partition &part : partitions) {
     auto add = [&](SyntheticSection &sec) {
       sec.partition = part.getNumber();