[Sparc] Include __tls_get_addr in symbol table for TLS calls to it

Global Dynamic and Local Dynamic call relocations only implicitly
reference __tls_get_addr; there is no connection in the ELF file between
the relocations and the symbol other than the specification for the
relocations' semantics. However, it still needs to be in the symbol
table despite the lack of explicit references to the symbol table entry,
since it needs to be bound at link time for these relocations, otherwise
any objects will fail to link.

For details, see https://sourceware.org/bugzilla/show_bug.cgi?id=22832.

Path by: James Clarke (jrtc27)

Differential revision: https://reviews.llvm.org/D43271

llvm-svn: 325688

2 files changed, 29 insertions, 6 deletions

diff --git a/llvm/lib/Target/Sparc/MCTargetDesc/SparcMCExpr.cpp b/llvm/lib/Target/Sparc/MCTargetDesc/SparcMCExpr.cpp
index a77f760d9ef..2b80293df12 100644
--- a/llvm/lib/Target/Sparc/MCTargetDesc/SparcMCExpr.cpp
+++ b/llvm/lib/Target/Sparc/MCTargetDesc/SparcMCExpr.cpp
@@ -193,14 +193,26 @@ static void fixELFSymbolsInTLSFixupsImpl(const MCExpr *Expr, MCAssembler &Asm) {
 void SparcMCExpr::fixELFSymbolsInTLSFixups(MCAssembler &Asm) const {
   switch(getKind()) {
   default: return;
+  case VK_Sparc_TLS_GD_CALL:
+  case VK_Sparc_TLS_LDM_CALL: {
+    // The corresponding relocations reference __tls_get_addr, as they call it,
+    // but this is only implicit; we must explicitly add it to our symbol table
+    // to bind it for these uses.
+    MCSymbol *Symbol = Asm.getContext().getOrCreateSymbol("__tls_get_addr");
+    Asm.registerSymbol(*Symbol);
+    auto ELFSymbol = cast<MCSymbolELF>(Symbol);
+    if (!ELFSymbol->isBindingSet()) {
+      ELFSymbol->setBinding(ELF::STB_GLOBAL);
+      ELFSymbol->setExternal(true);
+    }
+    LLVM_FALLTHROUGH;
+  }
   case VK_Sparc_TLS_GD_HI22:
   case VK_Sparc_TLS_GD_LO10:
   case VK_Sparc_TLS_GD_ADD:
-  case VK_Sparc_TLS_GD_CALL:
   case VK_Sparc_TLS_LDM_HI22:
   case VK_Sparc_TLS_LDM_LO10:
   case VK_Sparc_TLS_LDM_ADD:
-  case VK_Sparc_TLS_LDM_CALL:
   case VK_Sparc_TLS_LDO_HIX22:
   case VK_Sparc_TLS_LDO_LOX10:
   case VK_Sparc_TLS_LDO_ADD:
diff --git a/llvm/test/CodeGen/SPARC/tls.ll b/llvm/test/CodeGen/SPARC/tls.ll
index 8ebd36833ba..04bd5eee947 100644
--- a/llvm/test/CodeGen/SPARC/tls.ll
+++ b/llvm/test/CodeGen/SPARC/tls.ll
@@ -3,10 +3,10 @@
 ; RUN: llc <%s -march=sparc   -relocation-model=pic    | FileCheck %s --check-prefix=pic
 ; RUN: llc <%s -march=sparcv9 -relocation-model=pic    | FileCheck %s --check-prefix=pic
 
-; RUN: llc <%s -march=sparc   -relocation-model=static -filetype=obj | llvm-readobj -r | FileCheck %s --check-prefix=v8abs-obj
-; RUN: llc <%s -march=sparcv9 -relocation-model=static -filetype=obj | llvm-readobj -r | FileCheck %s --check-prefix=v9abs-obj
-; RUN: llc <%s -march=sparc   -relocation-model=pic    -filetype=obj | llvm-readobj -r | FileCheck %s --check-prefix=pic-obj
-; RUN: llc <%s -march=sparcv9 -relocation-model=pic    -filetype=obj | llvm-readobj -r | FileCheck %s --check-prefix=pic-obj
+; RUN: llc <%s -march=sparc   -relocation-model=static -filetype=obj | llvm-readobj -r -t | FileCheck %s --check-prefix=v8abs-obj
+; RUN: llc <%s -march=sparcv9 -relocation-model=static -filetype=obj | llvm-readobj -r -t | FileCheck %s --check-prefix=v9abs-obj
+; RUN: llc <%s -march=sparc   -relocation-model=pic    -filetype=obj | llvm-readobj -r -t | FileCheck %s --check-prefix=pic-obj
+; RUN: llc <%s -march=sparcv9 -relocation-model=pic    -filetype=obj | llvm-readobj -r -t | FileCheck %s --check-prefix=pic-obj
 
 @local_symbol = internal thread_local global i32 0
 @extern_symbol = external thread_local global i32
@@ -116,4 +116,15 @@ entry:
 ; pic-obj:    0x{{[0-9,A-F]+}} R_SPARC_TLS_GD_ADD extern_symbol 0x0
 ; pic-obj:    0x{{[0-9,A-F]+}} R_SPARC_TLS_GD_CALL extern_symbol 0x0
 ; pic-obj: ]
+; pic-obj:      Symbols [
+; pic-obj:        Symbol {
+; pic-obj:          Name: __tls_get_addr ({{[0-9]+}})
+; pic-obj-NEXT:     Value: 0x0
+; pic-obj-NEXT:     Size: 0
+; pic-obj-NEXT:     Binding: Global (0x1)
+; pic-obj-NEXT:     Type: None (0x0)
+; pic-obj-NEXT:     Other: 0
+; pic-obj-NEXT:     Section: Undefined (0x0)
+; pic-obj-NEXT:   }
+; pic-obj:      ]