[lld] r309605 - Never export weak undefined from executable.

[Rafael Espindola via llvm-commits]

Author: rafael
Date: Mon Jul 31 11:52:47 2017
New Revision: 309605

URL: http://llvm.org/viewvc/llvm-project?rev=309605&view=rev
Log:
Never export weak undefined from executable.

Before we were doing it with --export-dynamic. That seems incorrect.
The intention of --export-dynamic is to export symbols *defined* in
the executable.

Modified:
    lld/trunk/ELF/Symbols.cpp
    lld/trunk/test/ELF/weak-undef-export.s

Modified: lld/trunk/ELF/Symbols.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Symbols.cpp?rev=309605&r1=309604&r2=309605&view=diff
==============================================================================
--- lld/trunk/ELF/Symbols.cpp (original)
+++ lld/trunk/ELF/Symbols.cpp Mon Jul 31 11:52:47 2017
@@ -357,8 +357,9 @@ uint8_t Symbol::computeBinding() const {
 bool Symbol::includeInDynsym() const {
   if (computeBinding() == STB_LOCAL)
     return false;
-  return ExportDynamic || body()->isShared() ||
-         (body()->isUndefined() && Config->Shared);
+  if (body()->isUndefined())
+    return Config->Shared;
+  return ExportDynamic || body()->isShared();
 }
 
 // Print out a log message for --trace-symbol.

Modified: lld/trunk/test/ELF/weak-undef-export.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/weak-undef-export.s?rev=309605&r1=309604&r2=309605&view=diff
==============================================================================
--- lld/trunk/test/ELF/weak-undef-export.s (original)
+++ lld/trunk/test/ELF/weak-undef-export.s Mon Jul 31 11:52:47 2017
@@ -4,6 +4,19 @@
 
 # RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
 # RUN: ld.lld --export-dynamic %t.o -o %t
+# RUN: llvm-readobj -dyn-symbols %t | FileCheck %s
+
+# CHECK:      DynamicSymbols [
+# CHECK-NEXT:   Symbol {
+# CHECK-NEXT:     Name: @ (0)
+# CHECK-NEXT:     Value: 0x0
+# CHECK-NEXT:     Size: 0
+# CHECK-NEXT:     Binding: Local (0x0)
+# CHECK-NEXT:     Type: None (0x0)
+# CHECK-NEXT:     Other: 0
+# CHECK-NEXT:     Section: Undefined (0x0)
+# CHECK-NEXT:   }
+# CHECK-NEXT: ]
 
         .weak foo
         .quad foo