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, 10 insertions, 3 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCSubtarget.cpp b/llvm/lib/Target/PowerPC/PPCSubtarget.cpp
index 14b8534d1cb..9c8cb92cc7e 100644
--- a/llvm/lib/Target/PowerPC/PPCSubtarget.cpp
+++ b/llvm/lib/Target/PowerPC/PPCSubtarget.cpp
@@ -54,19 +54,26 @@ PPCSubtarget::PPCSubtarget(const std::string &TT, const std::string &CPU,
     CPUName = sys::getHostCPUName();
 #endif
 
-  // Parse features string.
-  ParseSubtargetFeatures(CPUName, FS);
-
   // Initialize scheduling itinerary for the specified CPU.
   InstrItins = getInstrItineraryForCPU(CPUName);
 
+  // Make sure 64-bit features are available when CPUname is generic
+  std::string FullFS = FS;
+
   // If we are generating code for ppc64, verify that options make sense.
   if (is64Bit) {
     Has64BitSupport = true;
     // Silently force 64-bit register use on ppc64.
     Use64BitRegs = true;
+    if (!FullFS.empty())
+      FullFS = "+64bit," + FullFS;
+    else
+      FullFS = "+64bit";
   }
 
+  // Parse features string.
+  ParseSubtargetFeatures(CPUName, FullFS);
+
   // If the user requested use of 64-bit regs, but the cpu selected doesn't
   // support it, ignore.
   if (use64BitRegs() && !has64BitSupport())