From 8c7f9745de6fb7d548efa8e56019e132813be5f8 Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Tue, 5 Oct 2010 23:57:26 +0000
Subject: [PATCH] Use a relocation against the symbol if it is a PLT and the
 symbol is in another section. Common because of linkonce sections.

llvm-svn: 115718
---
 lib/MC/ELFObjectWriter.cpp | 13 +++++++++++--
 test/MC/ELF/merge.s        | 24 ++++++++++++++++++++----
 2 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/lib/MC/ELFObjectWriter.cpp b/lib/MC/ELFObjectWriter.cpp
index d79029106b0..9f9681ae3ef 100644
--- a/lib/MC/ELFObjectWriter.cpp
+++ b/lib/MC/ELFObjectWriter.cpp
@@ -529,7 +529,8 @@ void ELFObjectWriterImpl::WriteSymbolTable(MCDataFragment *F,
 }
 
 static bool ShouldRelocOnSymbol(const MCSymbolData &SD,
-                                const MCValue &Target) {
+                                const MCValue &Target,
+                                const MCFragment &F) {
   const MCSymbol &Symbol = SD.getSymbol();
   if (Symbol.isUndefined())
     return true;
@@ -543,6 +544,14 @@ static bool ShouldRelocOnSymbol(const MCSymbolData &SD,
   if (SD.isExternal())
     return true;
 
+  const llvm::MCSymbolRefExpr& Ref = *Target.getSymA();
+  const MCSectionELF &Sec2 =
+    static_cast<const MCSectionELF&>(F.getParent()->getSection());
+
+  if (Ref.getKind() == MCSymbolRefExpr::VK_PLT &&
+      &Sec2 != &Section)
+    return true;
+
   return false;
 }
 
@@ -587,7 +596,7 @@ void ELFObjectWriterImpl::RecordRelocation(const MCAssembler &Asm,
       return;
     }
 
-    bool RelocOnSymbol = ShouldRelocOnSymbol(SD, Target);
+    bool RelocOnSymbol = ShouldRelocOnSymbol(SD, Target, *Fragment);
     if (!RelocOnSymbol) {
       Index = F->getParent()->getOrdinal();
 
diff --git a/test/MC/ELF/merge.s b/test/MC/ELF/merge.s
index 00ffd5ee9a8..227d4140e16 100644
--- a/test/MC/ELF/merge.s
+++ b/test/MC/ELF/merge.s
@@ -10,10 +10,14 @@
         movsd   .Lfoo(%rip), %xmm1
         movl	$.Lfoo, %edi
         movl	$.Lfoo+2, %edi
+        jmp	foo@PLT
 
         .section        .sec1,"aM",@progbits,16
 .Lfoo:
 
+        .section	bar,"ax",@progbits
+foo:
+
 // Section 4 is "sec1"
 // CHECK: # Section 4
 // CHECK-NEXT:  (('sh_name', 18) # '.sec1'
@@ -22,8 +26,12 @@
 // CHECK:      # Symbol 1
 // CHECK-NEXT: (('st_name', 1) # '.Lfoo'
 
-// Symbol number 5 is section 4
-// CHECK:        # Symbol 5
+// Symbol number 2 is foo
+// CHECK:      # Symbol 2
+// CHECK-NEXT: (('st_name', 7) # 'foo'
+
+// Symbol number 6 is section 4
+// CHECK:        # Symbol 6
 // CHECK-NEXT:    (('st_name', 0) # ''
 // CHECK-NEXT:     ('st_bind', 0)
 // CHECK-NEXT:     ('st_type', 3)
@@ -39,10 +47,10 @@
 // CHECK-NEXT:    ('r_addend',
 // CHECK-NEXT:   ),
 
-// Relocation 1 refers to symbol 5
+// Relocation 1 refers to symbol 6
 // CHECK-NEXT:  # Relocation 1
 // CHECK-NEXT: (('r_offset',
-// CHECK-NEXT:  ('r_sym', 5)
+// CHECK-NEXT:  ('r_sym', 6)
 // CHECK-NEXT:  ('r_type', 10)
 // CHECK-NEXT:  ('r_addend',
 // CHECK-NEXT: ),
@@ -54,4 +62,12 @@
 // CHECK-NEXT:    ('r_type', 10
 // CHECK-NEXT:    ('r_addend',
 // CHECK-NEXT:   ),
+
+// Relocation 3 refers to symbol 2
+// CHECK-NEXT:   # Relocation 3
+// CHECK-NEXT:   (('r_offset',
+// CHECK-NEXT:    ('r_sym', 2)
+// CHECK-NEXT:    ('r_type', 4
+// CHECK-NEXT:    ('r_addend',
+// CHECK-NEXT:   ),
 // CHECK-NEXT:  ])