From 634820d414acd9708b65b72af48e90355c631737 Mon Sep 17 00:00:00 2001
From: Jordan Rupprecht <rupprecht@google.com>
Date: Tue, 30 Oct 2018 16:23:38 +0000
Subject: [PATCH] [llvm-objcopy] Fix --keep-global-symbol/--globalize-symbol
 for undefined symbols.

Summary: --keep-global-symbol and --globalize-symbol don't make sense for undefined symbols, so it should be ignored for those symbols. This matches GNU objcopy behavior.

Reviewers: jhenderson, alexshap, jakehehrlich, espindola

Reviewed By: jhenderson, jakehehrlich

Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D53733

llvm-svn: 345614
---
 llvm/test/tools/llvm-objcopy/globalize.test           | 15 ++++++++++++++-
 llvm/test/tools/llvm-objcopy/keep-global-symbols.test | 10 +++++++---
 llvm/tools/llvm-objcopy/ELF/ELFObjcopy.cpp            |  6 ++++--
 3 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/llvm/test/tools/llvm-objcopy/globalize.test b/llvm/test/tools/llvm-objcopy/globalize.test
index 5c9d62e..4941cf1 100644
--- a/llvm/test/tools/llvm-objcopy/globalize.test
+++ b/llvm/test/tools/llvm-objcopy/globalize.test
@@ -1,5 +1,8 @@
 # RUN: yaml2obj %s > %t
-# RUN: llvm-objcopy --globalize-symbol Global --globalize-symbol Local --globalize-symbol Weak %t %t2
+# RUN: llvm-objcopy --globalize-symbol Global \
+# RUN:   --globalize-symbol Local \
+# RUN:   --globalize-symbol Weak \
+# RUN:   --globalize-symbol WeakUndef %t %t2
 # RUN: llvm-readobj -symbols %t2 | FileCheck %s
 
 !ELF
@@ -28,6 +31,7 @@ Symbols:
       Size:     8
       Section:  .text
       Value:    0x1008
+    - Name:     WeakUndef
   Global:
     - Name:     Global
       Type:     STT_FUNC
@@ -72,4 +76,13 @@ Symbols:
 #CHECK-NEXT:    Other: 0
 #CHECK-NEXT:    Section: .text
 #CHECK-NEXT:  }
+#CHECK-NEXT:  Symbol {
+#CHECK-NEXT:    Name: WeakUndef
+#CHECK-NEXT:    Value: 0x0
+#CHECK-NEXT:    Size: 0
+#CHECK-NEXT:    Binding: Weak
+#CHECK-NEXT:    Type: None
+#CHECK-NEXT:    Other: 0
+#CHECK-NEXT:    Section: Undefined
+#CHECK-NEXT:  }
 #CHECK-NEXT:]
diff --git a/llvm/test/tools/llvm-objcopy/keep-global-symbols.test b/llvm/test/tools/llvm-objcopy/keep-global-symbols.test
index 4f580b4..8ce1d7f 100644
--- a/llvm/test/tools/llvm-objcopy/keep-global-symbols.test
+++ b/llvm/test/tools/llvm-objcopy/keep-global-symbols.test
@@ -18,6 +18,8 @@
 # "Global5 Global6": Global, because it appears in %t-globals2.txt, but we only
 #     trim leading and trailing whitespace. We don't just take the first chunk
 #     that looks like a symbol.
+# Global7: Global, because even though it doesn't appear as any -G flags, does
+#     not get demoted since it's undefined.
 
 # RUN: echo Global2 > %t-globals1.txt
 # RUN: echo "  Global3  " > %t-globals2.txt
@@ -77,8 +79,9 @@ Symbols:
       Section:     .text
     - Name:        "Global5 Global6"
       Section:     .text
+    - Name:        Global7
 
-# CHECK:      Symbol table '.symtab' contains 13 entries:
+# CHECK:      Symbol table '.symtab' contains 14 entries:
 # CHECK-NEXT:    Num: Value Size Type Bind Vis Ndx Name
 # CHECK-NEXT:      0: {{.*}}  LOCAL  {{.*}}
 # CHECK-NEXT:      1: {{.*}}  LOCAL  {{.*}} Local1
@@ -91,5 +94,6 @@ Symbols:
 # CHECK-NEXT:      8: {{.*}}  GLOBAL {{.*}} Global3
 # CHECK-NEXT:      9: {{.*}}  GLOBAL {{.*}} Global4
 # CHECK-NEXT:     10: {{.*}}  GLOBAL {{.*}} Global5 Global6
-# CHECK-NEXT:     11: {{.*}}  WEAK   {{.*}} Weak1
-# CHECK-NEXT:     12: {{.*}}  GLOBAL {{.*}} Weak2
+# CHECK-NEXT:     11: {{.*}}  GLOBAL {{.*}} UND Global7
+# CHECK-NEXT:     12: {{.*}}  WEAK   {{.*}} Weak1
+# CHECK-NEXT:     13: {{.*}}  GLOBAL {{.*}} Weak2
diff --git a/llvm/tools/llvm-objcopy/ELF/ELFObjcopy.cpp b/llvm/tools/llvm-objcopy/ELF/ELFObjcopy.cpp
index 7637978..2bad270 100644
--- a/llvm/tools/llvm-objcopy/ELF/ELFObjcopy.cpp
+++ b/llvm/tools/llvm-objcopy/ELF/ELFObjcopy.cpp
@@ -230,11 +230,13 @@ static void handleArgs(const CopyConfig &Config, Object &Obj,
       // --keep-global-symbol. Because of that, make sure to check
       // --globalize-symbol second.
       if (!Config.SymbolsToKeepGlobal.empty() &&
-          !is_contained(Config.SymbolsToKeepGlobal, Sym.Name))
+          !is_contained(Config.SymbolsToKeepGlobal, Sym.Name) &&
+          Sym.getShndx() != SHN_UNDEF)
         Sym.Binding = STB_LOCAL;
 
       if (!Config.SymbolsToGlobalize.empty() &&
-          is_contained(Config.SymbolsToGlobalize, Sym.Name))
+          is_contained(Config.SymbolsToGlobalize, Sym.Name) &&
+          Sym.getShndx() != SHN_UNDEF)
         Sym.Binding = STB_GLOBAL;
 
       if (!Config.SymbolsToWeaken.empty() &&
-- 
2.7.4