[PATCH] D104353: [lld-macho] Avoid force-loading the same archive twice

[Jez Ng via Phabricator via llvm-commits]

int3 updated this revision to Diff 352343.
int3 added a comment.

tweak test


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D104353/new/

https://reviews.llvm.org/D104353

Files:
  lld/MachO/Driver.cpp
  lld/test/MachO/force-load.s


Index: lld/test/MachO/force-load.s
===================================================================
--- lld/test/MachO/force-load.s
+++ lld/test/MachO/force-load.s
@@ -13,11 +13,21 @@
 # RUN: llvm-objdump --syms %t/test-force-load-second | FileCheck %s --check-prefix=FORCE-LOAD-SECOND
 # FORCE-LOAD-SECOND: __TEXT,obj _foo
 
+## Force-loading the same path twice is fine
+# RUN: %lld %t/foo.o -force_load %t/foo.a -force_load %t/foo.a %t/test.o -o /dev/null
+
+## Note that we do not call realpath() before dedup'ing the force-load
+## arguments, so this is an error.
+# RUN: cd %t; not %lld %t/foo.o -force_load %t/foo.a -force_load foo.a \
+# RUN:   %t/test.o -o /dev/null 2>&1 | FileCheck %s --check-prefix=DUP
+# DUP: error: duplicate symbol: _bar
+
 #--- archive-foo.s
 .section __TEXT,archive
-.globl _foo
+.globl _foo, _bar
 .weak_definition _foo
 _foo:
+_bar:
 
 #--- foo.s
 .section __TEXT,obj
Index: lld/MachO/Driver.cpp
===================================================================
--- lld/MachO/Driver.cpp
+++ lld/MachO/Driver.cpp
@@ -235,6 +235,8 @@
   return v;
 }
 
+static DenseMap<StringRef, ArchiveFile *> loadedArchives;
+
 static InputFile *addFile(StringRef path, bool forceLoadArchive,
                           bool isExplicit = true,
                           bool isBundleLoader = false) {
@@ -247,6 +249,13 @@
   file_magic magic = identify_magic(mbref.getBuffer());
   switch (magic) {
   case file_magic::archive: {
+    // Avoid loading archives twice. If the archives are being force-loaded,
+    // loading them twice would create duplicate symbol errors. In the
+    // non-force-loading case, this is just a minor performance optimization.
+    ArchiveFile *&cachedFile = loadedArchives[path];
+    if (cachedFile)
+      return cachedFile;
+
     std::unique_ptr<object::Archive> file = CHECK(
         object::Archive::create(mbref), path + ": failed to parse archive");
 
@@ -286,7 +295,7 @@
       }
     }
 
-    newFile = make<ArchiveFile>(std::move(file));
+    newFile = cachedFile = make<ArchiveFile>(std::move(file));
     break;
   }
   case file_magic::macho_object:


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