[PATCH] D147960: [lld-macho] Cache discovered dylib paths

[Keith Smiley via Phabricator via llvm-commits]

keith created this revision.
Herald added projects: lld-macho, All.
Herald added a reviewer: lld-macho.
keith requested review of this revision.
Herald added a project: LLVM.
Herald added a subscriber: llvm-commits.

In cases where you have many dylibs referenced by load commands, this
would be accessed repeated times for the same dylibs causing huge time
spikes.

Fixes https://github.com/keith/rules_apple_linker/issues/38


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D147960

Files:
  lld/MachO/DriverUtils.cpp


Index: lld/MachO/DriverUtils.cpp
===================================================================
--- lld/MachO/DriverUtils.cpp
+++ lld/MachO/DriverUtils.cpp
@@ -186,20 +186,32 @@
     depTracker->logFileNotFound(path);
 }
 
+static DenseMap<CachedHashStringRef, StringRef> resolvedDylibs;
 std::optional<StringRef> macho::resolveDylibPath(StringRef dylibPath) {
+  CachedHashStringRef key(dylibPath);
+  auto entry = resolvedDylibs.find(key);
+  if (entry != resolvedDylibs.end())
+    return entry->second;
+
   // TODO: if a tbd and dylib are both present, we should check to make sure
   // they are consistent.
   SmallString<261> tbdPath = dylibPath;
   path::replace_extension(tbdPath, ".tbd");
   bool tbdExists = fs::exists(tbdPath);
   searchedDylib(tbdPath, tbdExists);
-  if (tbdExists)
-    return saver().save(tbdPath.str());
+  if (tbdExists) {
+    StringRef file = saver().save(tbdPath.str());
+    resolvedDylibs[key] = file;
+    return file;
+  }
 
   bool dylibExists = fs::exists(dylibPath);
   searchedDylib(dylibPath, dylibExists);
-  if (dylibExists)
-    return saver().save(dylibPath);
+  if (dylibExists) {
+    StringRef file = saver().save(dylibPath);
+    resolvedDylibs[key] = file;
+    return file;
+  }
   return {};
 }
 
@@ -253,7 +265,10 @@
   return newFile;
 }
 
-void macho::resetLoadedDylibs() { loadedDylibs.clear(); }
+void macho::resetLoadedDylibs() {
+  resolvedDylibs.clear();
+  loadedDylibs.clear();
+}
 
 std::optional<StringRef>
 macho::findPathCombination(const Twine &name,


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D147960.512215.patch
Type: text/x-patch
Size: 1529 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20230410/ee7d11d3/attachment.bin>