Revert "[MC] Emit unused undefined symbol even if its binding is not set"

This reverts r373168. It caused PR43511.

llvm-svn: 373242

5 files changed, 9 insertions, 37 deletions

diff --git a/lld/test/ELF/ppc64-abs64-dyn.s b/lld/test/ELF/ppc64-abs64-dyn.s
index 45d10b28004..24976316c45 100644
--- a/lld/test/ELF/ppc64-abs64-dyn.s
+++ b/lld/test/ELF/ppc64-abs64-dyn.s
@@ -12,10 +12,10 @@
 
 ## FIXME the addend for offset 0x20000 should be TOC base+0x8000+1, not 0x80001.
 # CHECK:      .rela.dyn {
-# CHECK-NEXT:   0x303B8 R_PPC64_RELATIVE - 0x8001
-# CHECK-NEXT:   0x303C0 R_PPC64_RELATIVE - 0x303B9
-# CHECK-NEXT:   0x303C8 R_PPC64_ADDR64 external 0x1
-# CHECK-NEXT:   0x303D0 R_PPC64_ADDR64 global 0x1
+# CHECK-NEXT:   0x303B0 R_PPC64_RELATIVE - 0x8001
+# CHECK-NEXT:   0x303B8 R_PPC64_RELATIVE - 0x303B1
+# CHECK-NEXT:   0x303C0 R_PPC64_ADDR64 external 0x1
+# CHECK-NEXT:   0x303C8 R_PPC64_ADDR64 global 0x1
 # CHECK-NEXT: }
 
 .data
diff --git a/lld/test/ELF/ppc64-relocs.s b/lld/test/ELF/ppc64-relocs.s
index e3363b60488..0fe0edfc576 100644
--- a/lld/test/ELF/ppc64-relocs.s
+++ b/lld/test/ELF/ppc64-relocs.s
@@ -26,13 +26,13 @@ _start:
   ld 1, .L1@toc@l(2)
 
 # CHECK-LABEL: Disassembly of section .R_PPC64_TOC16_LO_DS:
-# CHECK: ld 1, -32760(2)
+# CHECK: ld 1, -32768(2)
 
 .section .R_PPC64_TOC16_LO,"ax",@progbits
   addi  1, 2, .L1@toc@l
 
 # CHECK-LABEL: Disassembly of section .R_PPC64_TOC16_LO:
-# CHECK: addi 1, 2, -32760
+# CHECK: addi 1, 2, -32768
 
 .section .R_PPC64_TOC16_HI,"ax",@progbits
   addis 1, 2, .L1@toc@h
diff --git a/llvm/lib/MC/ELFObjectWriter.cpp b/llvm/lib/MC/ELFObjectWriter.cpp
index f8e93889344..6f160e491ce 100644
--- a/llvm/lib/MC/ELFObjectWriter.cpp
+++ b/llvm/lib/MC/ELFObjectWriter.cpp
@@ -615,6 +615,9 @@ bool ELFWriter::isInSymtab(const MCAsmLayout &Layout, const MCSymbolELF &Symbol,
     return false;
   }
 
+  if (Symbol.isUndefined() && !Symbol.isBindingSet())
+    return false;
+
   if (Symbol.isTemporary())
     return false;
 
diff --git a/llvm/test/MC/ELF/undef.s b/llvm/test/MC/ELF/undef.s
index 9d99b834ffd..f313d71369e 100644
--- a/llvm/test/MC/ELF/undef.s
+++ b/llvm/test/MC/ELF/undef.s
@@ -18,8 +18,6 @@
         .text
         movsd   .Lsym8(%rip), %xmm1
 
-.hidden hidden
-
 test2_a = undef
 test2_b = undef + 1
 
@@ -43,17 +41,6 @@ test2_b = undef + 1
 // CHECK-NEXT:     Section: .rodata.str1.1
 // CHECK-NEXT:   }
 // CHECK-NEXT:   Symbol {
-// CHECK-NEXT:     Name: hidden
-// CHECK-NEXT:     Value: 0x0
-// CHECK-NEXT:     Size: 0
-// CHECK-NEXT:     Binding: Global
-// CHECK-NEXT:     Type: None
-// CHECK-NEXT:     Other [
-// CHECK-NEXT:       STV_HIDDEN
-// CHECK-NEXT:     ]
-// CHECK-NEXT:     Section: Undefined
-// CHECK-NEXT:   }
-// CHECK-NEXT:   Symbol {
 // CHECK-NEXT:     Name: sym6
 // CHECK-NEXT:     Value: 0x0
 // CHECK-NEXT:     Size: 0
@@ -62,13 +49,4 @@ test2_b = undef + 1
 // CHECK-NEXT:     Other: 0
 // CHECK-NEXT:     Section: Undefined
 // CHECK-NEXT:   }
-// CHECK-NEXT:   Symbol {
-// CHECK-NEXT:     Name: undef
-// CHECK-NEXT:     Value: 0x0
-// CHECK-NEXT:     Size: 0
-// CHECK-NEXT:     Binding: Global
-// CHECK-NEXT:     Type: None
-// CHECK-NEXT:     Other: 0
-// CHECK-NEXT:     Section: Undefined
-// CHECK-NEXT:   }
 // CHECK-NEXT: ]
diff --git a/llvm/test/MC/ELF/weakref.s b/llvm/test/MC/ELF/weakref.s
index bca8ec4f281..51905d8ad7c 100644
--- a/llvm/test/MC/ELF/weakref.s
+++ b/llvm/test/MC/ELF/weakref.s
@@ -125,15 +125,6 @@ bar15:
 // CHECK-NEXT:     Section: .text
 // CHECK-NEXT:   }
 // CHECK-NEXT:   Symbol {
-// CHECK-NEXT:     Name: bar1
-// CHECK-NEXT:     Value: 0x0
-// CHECK-NEXT:     Size: 0
-// CHECK-NEXT:     Binding: Global
-// CHECK-NEXT:     Type: None
-// CHECK-NEXT:     Other: 0
-// CHECK-NEXT:     Section: Undefined
-// CHECK-NEXT:   }
-// CHECK-NEXT:   Symbol {
 // CHECK-NEXT:     Name: bar10
 // CHECK-NEXT:     Value: 0x28
 // CHECK-NEXT:     Size: 0