commit 1b003183712c7ae5710430a914f9ab660083da1d
author Rui Ueyama <ruiu@google.com> Tue Feb 28 19:22:09 2017 +0000
committer Rui Ueyama <ruiu@google.com> Tue Feb 28 19:22:09 2017 +0000
tree 6d821788e1b41c5b7d5a345de1bb908af8d789d1
parent 357d3db0a42ebca612a8ea442b409de94afa5f98

Make it obvious that st_value for common symbols has a different meaning.

llvm-svn: 296507

lld/ELF/SyntheticSections.cpp

diff --git a/lld/ELF/SyntheticSections.cpp b/lld/ELF/SyntheticSections.cpp
index eb717e8..62d0c0d1 100644
--- a/lld/ELF/SyntheticSections.cpp
+++ b/lld/ELF/SyntheticSections.cpp
@@ -1363,6 +1363,7 @@
   for (SymbolTableEntry &Ent : Symbols) {
     SymbolBody *Body = Ent.Symbol;
 
+    // Set st_info and st_other.
     if (Body->isLocal()) {
       ESym->setBindingAndType(STB_LOCAL, Body->Type);
     } else {
@@ -1372,16 +1373,23 @@
 
     ESym->st_name = Ent.StrTabOffset;
     ESym->st_size = Body->getSize<ELFT>();
-    ESym->st_value = Body->getVA<ELFT>();
 
-    if (const OutputSection *OutSec = Body->getOutputSection<ELFT>()) {
+    // Set a section index.
+    if (const OutputSection *OutSec = Body->getOutputSection<ELFT>())
       ESym->st_shndx = OutSec->SectionIndex;
-    } else if (isa<DefinedRegular<ELFT>>(Body)) {
+    else if (isa<DefinedRegular<ELFT>>(Body))
       ESym->st_shndx = SHN_ABS;
-    } else if (isa<DefinedCommon>(Body)) {
+    else if (isa<DefinedCommon>(Body))
       ESym->st_shndx = SHN_COMMON;
+
+    // st_value is usually an address of a symbol, but that has a
+    // special meaining for uninstantiated common symbols (this can
+    // occur if -r is given).
+    if (!Config->DefineCommon && isa<DefinedCommon>(Body))
       ESym->st_value = cast<DefinedCommon>(Body)->Alignment;
-    }
+    else
+      ESym->st_value = Body->getVA<ELFT>();
+
     ++ESym;
   }