[SPARC] Repair GOT references to internal symbols.

They had been getting emitted as a section + offset reference, which
is bogus since the value needs to be the offset within the GOT, not
the actual address of the symbol's object.

Differential Revision: http://reviews.llvm.org/D10441

llvm-svn: 240020

2 files changed, 34 insertions, 0 deletions

diff --git a/llvm/lib/Target/Sparc/AsmParser/SparcAsmParser.cpp b/llvm/lib/Target/Sparc/AsmParser/SparcAsmParser.cpp
index 021f904f6ee..4a33f7fc346 100644
--- a/llvm/lib/Target/Sparc/AsmParser/SparcAsmParser.cpp
+++ b/llvm/lib/Target/Sparc/AsmParser/SparcAsmParser.cpp
@@ -947,6 +947,8 @@ bool SparcAsmParser::matchRegisterName(const AsmToken &Tok,
   return false;
 }
 
+// Determine if an expression contains a reference to the symbol
+// "_GLOBAL_OFFSET_TABLE_".
 static bool hasGOTReference(const MCExpr *Expr) {
   switch (Expr->getKind()) {
   case MCExpr::Target:
@@ -998,6 +1000,13 @@ bool SparcAsmParser::matchSparcAsmModifiers(const MCExpr *&EVal,
 
   bool isPIC = getContext().getObjectFileInfo()->getRelocM() == Reloc::PIC_;
 
+  // Ugly: if a sparc assembly expression says "%hi(...)" but the
+  // expression within contains _GLOBAL_OFFSET_TABLE_, it REALLY means
+  // %pc22. Same with %lo -> %pc10. Worse, if it doesn't contain that,
+  // the meaning depends on whether the assembler was invoked with
+  // -KPIC or not: if so, it really means %got22/%got10; if not, it
+  // actually means what it said! Sigh, historical mistakes...
+
   switch(VK) {
   default: break;
   case SparcMCExpr::VK_Sparc_LO:
diff --git a/llvm/lib/Target/Sparc/MCTargetDesc/SparcELFObjectWriter.cpp b/llvm/lib/Target/Sparc/MCTargetDesc/SparcELFObjectWriter.cpp
index 4f07ae21920..0be60fd7a05 100644
--- a/llvm/lib/Target/Sparc/MCTargetDesc/SparcELFObjectWriter.cpp
+++ b/llvm/lib/Target/Sparc/MCTargetDesc/SparcELFObjectWriter.cpp
@@ -31,6 +31,10 @@ namespace {
   protected:
     unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
                           bool IsPCRel) const override;
+
+    bool needsRelocateWithSymbol(const MCSymbol &Sym,
+                                 unsigned Type) const override;
+
   };
 }
 
@@ -105,6 +109,27 @@ unsigned SparcELFObjectWriter::GetRelocType(const MCValue &Target,
   return ELF::R_SPARC_NONE;
 }
 
+bool SparcELFObjectWriter::needsRelocateWithSymbol(const MCSymbol &Sym,
+                                                 unsigned Type) const {
+  switch (Type) {
+    default:
+      return false;
+
+    // All relocations that use a GOT need a symbol, not an offset, as
+    // the offset of the symbol within the section is irrelevant to
+    // where the GOT entry is. Don't need to list all the TLS entries,
+    // as they're all marked as requiring a symbol anyways.
+    case ELF::R_SPARC_GOT10:
+    case ELF::R_SPARC_GOT13:
+    case ELF::R_SPARC_GOT22:
+    case ELF::R_SPARC_GOTDATA_HIX22:
+    case ELF::R_SPARC_GOTDATA_LOX10:
+    case ELF::R_SPARC_GOTDATA_OP_HIX22:
+    case ELF::R_SPARC_GOTDATA_OP_LOX10:
+      return true;
+  }
+}
+
 MCObjectWriter *llvm::createSparcELFObjectWriter(raw_pwrite_stream &OS,
                                                  bool Is64Bit,
                                                  bool IsLittleEndian,