Initial TOC support for PowerPC64 object creation

This patch adds initial PPC64 TOC MC object creation using the small mcmodel
(a single 64K TOC) adding the some TOC relocations (R_PPC64_TOC,
R_PPC64_TOC16, and R_PPC64_TOC16DS).

The addition of 'undefinedExplicitRelSym' hook on 'MCELFObjectTargetWriter'
is meant to avoid the creation of an unreferenced ".TOC." symbol (used in
the .odp creation) as well to set the R_PPC64_TOC relocation target as the
temporary ".TOC." symbol. On PPC64 ABI, the R_PPC64_TOC relocation should
not point to any symbol.

llvm-svn: 166677

1 files changed, 6 insertions, 2 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp b/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
index d8abd9fba07..6941413ed46 100644
--- a/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
+++ b/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
@@ -420,10 +420,14 @@ void PPCLinuxAsmPrinter::EmitFunctionEntryLabel() {
   OutStreamer.EmitValueToAlignment(8);
   MCSymbol *Symbol1 = 
     OutContext.GetOrCreateSymbol(".L." + Twine(CurrentFnSym->getName()));
-  MCSymbol *Symbol2 = OutContext.GetOrCreateSymbol(StringRef(".TOC.@tocbase"));
+  // Generates a R_PPC64_ADDR64 (from FK_DATA_8) relocation for the function
+  // entry point.
   OutStreamer.EmitValue(MCSymbolRefExpr::Create(Symbol1, OutContext),
                         8/*size*/, 0/*addrspace*/);
-  OutStreamer.EmitValue(MCSymbolRefExpr::Create(Symbol2, OutContext),
+  MCSymbol *Symbol2 = OutContext.GetOrCreateSymbol(StringRef(".TOC."));
+  // Generates a R_PPC64_TOC relocation for TOC base insertion.
+  OutStreamer.EmitValue(MCSymbolRefExpr::Create(Symbol2,
+                        MCSymbolRefExpr::VK_PPC_TOC, OutContext),
                         8/*size*/, 0/*addrspace*/);
   // Emit a null environment pointer.
   OutStreamer.EmitIntValue(0, 8 /* size */, 0 /* addrspace */);