From f571f9a8fe764d5010970e45203415cb00eab739 Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Thu, 28 Oct 2010 18:33:03 +0000
Subject: [PATCH] Aliases defined with .symver should copy the binding of the
 symbols they alias. Move the existing patching for undefined symbols so that
 all the patching is done in the same function.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117570 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/MC/ELFObjectWriter.cpp | 27 +++++++++++++++++++++------
 test/MC/ELF/symref.s       | 29 ++++++++++++++++++++++++++---
 2 files changed, 47 insertions(+), 9 deletions(-)

diff --git a/lib/MC/ELFObjectWriter.cpp b/lib/MC/ELFObjectWriter.cpp
index b979de9322c..ef2901d7497 100644
--- a/lib/MC/ELFObjectWriter.cpp
+++ b/lib/MC/ELFObjectWriter.cpp
@@ -465,14 +465,32 @@ void ELFObjectWriterImpl::ExecutePostLayoutBinding(MCAssembler &Asm) {
   for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
          ie = Asm.symbol_end(); it != ie; ++it) {
     const MCSymbol &Alias = it->getSymbol();
-    if (!Alias.isVariable())
-      continue;
     const MCSymbol &Symbol = AliasedSymbol(Alias);
+    MCSymbolData &SD = Asm.getSymbolData(Symbol);
+
+    // Undefined symbols are global, but this is the first place we
+    // are able to set it.
+    if (Symbol.isUndefined() && !Symbol.isVariable()) {
+      if (GetBinding(SD) == ELF::STB_LOCAL) {
+        SetBinding(SD, ELF::STB_GLOBAL);
+        SetBinding(*it, ELF::STB_GLOBAL);
+      }
+    }
+
+    // Not an alias.
+    if (&Symbol == &Alias)
+      continue;
+
     StringRef AliasName = Alias.getName();
     size_t Pos = AliasName.find('@');
     if (Pos == StringRef::npos)
       continue;
 
+    // Aliases defined with .symvar copy the binding from the symbol they alias.
+    // This is the first place we are able to copy this information.
+    it->setExternal(SD.isExternal());
+    SetBinding(*it, GetBinding(SD));
+
     StringRef Rest = AliasName.substr(Pos);
     if (!Symbol.isUndefined() && !Rest.startswith("@@@"))
       continue;
@@ -881,6 +899,7 @@ void ELFObjectWriterImpl::ComputeSymbolTable(MCAssembler &Asm) {
     MCSymbol *Sym = Asm.getContext().GetOrCreateSymbol(Name);
     MCSymbolData &Data = Asm.getOrCreateSymbolData(*Sym);
     Data.setExternal(true);
+    SetBinding(Data, ELF::STB_GLOBAL);
   }
 
   // Build section lookup table.
@@ -916,10 +935,6 @@ void ELFObjectWriterImpl::ComputeSymbolTable(MCAssembler &Asm) {
       MSD.SectionIndex = ELF::SHN_ABS;
     } else if (RefSymbol.isUndefined()) {
       MSD.SectionIndex = ELF::SHN_UNDEF;
-      // FIXME: Undefined symbols are global, but this is the first place we
-      // are able to set it.
-      if (GetBinding(*it) == ELF::STB_LOCAL)
-        SetBinding(*it, ELF::STB_GLOBAL);
     } else {
       MSD.SectionIndex = SectionIndexMap.lookup(&RefSymbol.getSection());
       assert(MSD.SectionIndex && "Invalid section index!");
diff --git a/test/MC/ELF/symref.s b/test/MC/ELF/symref.s
index df2395e9a08..f1563e58adc 100644
--- a/test/MC/ELF/symref.s
+++ b/test/MC/ELF/symref.s
@@ -17,6 +17,11 @@ defined3:
         .long defined3
         .long undefined3
 
+        .global global1
+        .symver global1, g1@@zed
+global1:
+
+
 // CHECK:      # Symbol 0x00000001
 // CHECK-NEXT: (('st_name', 0x00000013) # 'bar1@zed'
 // CHECK-NEXT:  ('st_bind', 0x00000000)
@@ -90,6 +95,24 @@ defined3:
 // CHECK-NEXT:  ('st_size', 0x00000000)
 // CHECK-NEXT: ),
 // CHECK-NEXT: # Symbol 0x00000009
+// CHECK-NEXT: (('st_name', 0x0000004a) # 'g1@@zed'
+// CHECK-NEXT:  ('st_bind', 0x00000001)
+// CHECK-NEXT:  ('st_type', 0x00000000)
+// CHECK-NEXT:  ('st_other', 0x00000000)
+// CHECK-NEXT:  ('st_shndx', 0x00000001)
+// CHECK-NEXT:  ('st_value', 0x00000014)
+// CHECK-NEXT:  ('st_size', 0x00000000)
+// CHECK-NEXT: ),
+// CHECK-NEXT: # Symbol 0x0000000a
+// CHECK-NEXT: (('st_name', 0x00000042) # 'global1'
+// CHECK-NEXT:  ('st_bind', 0x00000001)
+// CHECK-NEXT:  ('st_type', 0x00000000)
+// CHECK-NEXT:  ('st_other', 0x00000000)
+// CHECK-NEXT:  ('st_shndx', 0x00000001)
+// CHECK-NEXT:  ('st_value', 0x00000014)
+// CHECK-NEXT:  ('st_size', 0x00000000)
+// CHECK-NEXT: ),
+// CHECK-NEXT: # Symbol 0x0000000b
 // CHECK-NEXT: (('st_name', 0x0000001c) # 'bar2@zed'
 // CHECK-NEXT:  ('st_bind', 0x00000001)
 // CHECK-NEXT:  ('st_type', 0x00000000)
@@ -98,7 +121,7 @@ defined3:
 // CHECK-NEXT:  ('st_value', 0x00000000)
 // CHECK-NEXT:  ('st_size', 0x00000000)
 // CHECK-NEXT: ),
-// CHECK-NEXT: # Symbol 0x0000000a
+// CHECK-NEXT: # Symbol 0x0000000c
 // CHECK-NEXT: (('st_name', 0x00000039) # 'bar6@zed'
 // CHECK-NEXT:  ('st_bind', 0x00000001)
 // CHECK-NEXT:  ('st_type', 0x00000000)
@@ -117,7 +140,7 @@ defined3:
 // CHECK-NEXT: ),
 // CHECK-NEXT: # Relocation 0x00000001
 // CHECK-NEXT: (('r_offset', 0x00000004)
-// CHECK-NEXT:  ('r_sym', 0x00000009)
+// CHECK-NEXT:  ('r_sym', 0x0000000b)
 // CHECK-NEXT:  ('r_type', 0x0000000a)
 // CHECK-NEXT:  ('r_addend', 0x00000000)
 // CHECK-NEXT: ),
@@ -135,7 +158,7 @@ defined3:
 // CHECK-NEXT: ),
 // CHECK-NEXT: # Relocation 0x00000004
 // CHECK-NEXT: (('r_offset', 0x00000010)
-// CHECK-NEXT:  ('r_sym', 0x0000000a)
+// CHECK-NEXT:  ('r_sym', 0x0000000c)
 // CHECK-NEXT:  ('r_type', 0x0000000a)
 // CHECK-NEXT:  ('r_addend', 0x00000000)
 // CHECK-NEXT: ),