[PATCH] D53782: [llvm-objcopy] Don't apply --localize flags to common symbols

[Jordan Rupprecht via Phabricator via llvm-commits]

rupprecht created this revision.
rupprecht added reviewers: jakehehrlich, jhenderson, alexshap.
Herald added a subscriber: llvm-commits.

--localize-symbol and --localize-hidden will currently localize common symbols. GNU objcopy will not localize these symbols even when explicitly requested, which seems reasonable; common symbols should always be global so they can be merged during linking.

See PR39461


Repository:
  rL LLVM

https://reviews.llvm.org/D53782

Files:
  test/tools/llvm-objcopy/localize-hidden.test
  test/tools/llvm-objcopy/localize.test
  tools/llvm-objcopy/llvm-objcopy.cpp


Index: tools/llvm-objcopy/llvm-objcopy.cpp
===================================================================
--- tools/llvm-objcopy/llvm-objcopy.cpp
+++ tools/llvm-objcopy/llvm-objcopy.cpp
@@ -256,10 +256,11 @@
   // them.
   if (Obj.SymbolTable) {
     Obj.SymbolTable->updateSymbols([&](Symbol &Sym) {
-      if ((Config.LocalizeHidden &&
-           (Sym.Visibility == STV_HIDDEN || Sym.Visibility == STV_INTERNAL)) ||
-          (!Config.SymbolsToLocalize.empty() &&
-           is_contained(Config.SymbolsToLocalize, Sym.Name)))
+      if (Sym.getShndx() != SHN_COMMON &&
+          ((Config.LocalizeHidden &&
+            (Sym.Visibility == STV_HIDDEN || Sym.Visibility == STV_INTERNAL)) ||
+           (!Config.SymbolsToLocalize.empty() &&
+            is_contained(Config.SymbolsToLocalize, Sym.Name))))
         Sym.Binding = STB_LOCAL;
 
       // Note: these two globalize flags have very similar names but different
Index: test/tools/llvm-objcopy/localize.test
===================================================================
--- test/tools/llvm-objcopy/localize.test
+++ test/tools/llvm-objcopy/localize.test
@@ -1,5 +1,5 @@
 # RUN: yaml2obj %s > %t
-# RUN: llvm-objcopy --localize-symbol Global -L Local -L Weak %t %t2
+# RUN: llvm-objcopy --localize-symbol Global -L Local -L Weak -L GlobalCommon %t %t2
 # RUN: llvm-readobj -symbols %t2 | FileCheck %s
 
 !ELF
@@ -40,6 +40,11 @@
       Size:     8
       Section:  .text
       Value:    0x1010
+    - Name:     GlobalCommon
+      Type:     STT_OBJECT
+      Index:    SHN_COMMON
+      Value:    0x2006
+      Size:     2
 
 #CHECK: Symbols [
 #CHECK-NEXT:  Symbol {
@@ -78,4 +83,13 @@
 #CHECK-NEXT:    Other: 0
 #CHECK-NEXT:    Section: .text
 #CHECK-NEXT:  }
+#CHECK-NEXT:  Symbol {
+#CHECK-NEXT:    Name: GlobalCommon
+#CHECK-NEXT:    Value: 0x2006
+#CHECK-NEXT:    Size: 2
+#CHECK-NEXT:    Binding: Global
+#CHECK-NEXT:    Type: Object
+#CHECK-NEXT:    Other: 0
+#CHECK-NEXT:    Section: Common
+#CHECK-NEXT:  }
 #CHECK-NEXT:]
Index: test/tools/llvm-objcopy/localize-hidden.test
===================================================================
--- test/tools/llvm-objcopy/localize-hidden.test
+++ test/tools/llvm-objcopy/localize-hidden.test
@@ -55,6 +55,12 @@
       Value:    0x2006
       Size:     2
       Visibility: STV_HIDDEN
+    - Name:     hiddenGlobalCommon
+      Type:     STT_OBJECT
+      Index:    SHN_COMMON
+      Value:    0x2006
+      Size:     2
+      Visibility: STV_HIDDEN
     - Name:     undefGlobal
       Type:     STT_FUNC
       Size:     8
@@ -142,6 +148,17 @@
 #CHECK-NEXT:    Section: .text
 #CHECK-NEXT:  }
 #CHECK-NEXT:  Symbol {
+#CHECK-NEXT:    Name: hiddenGlobalCommon
+#CHECK-NEXT:    Value: 0x2006
+#CHECK-NEXT:    Size: 2
+#CHECK-NEXT:    Binding: Global
+#CHECK-NEXT:    Type: Object
+#CHECK-NEXT:    Other [
+#CHECK-NEXT:      STV_HIDDEN
+#CHECK-NEXT:    ]
+#CHECK-NEXT:    Section: Common
+#CHECK-NEXT:  }
+#CHECK-NEXT:  Symbol {
 #CHECK-NEXT:    Name: undefGlobal
 #CHECK-NEXT:    Value: 0x0
 #CHECK-NEXT:    Size: 8


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