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.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166677 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 112 insertions, 13 deletions

diff --git a/lib/Target/PowerPC/MCTargetDesc/PPCAsmBackend.cpp b/lib/Target/PowerPC/MCTargetDesc/PPCAsmBackend.cpp
index 1744738..87ecb13 100644
--- a/lib/Target/PowerPC/MCTargetDesc/PPCAsmBackend.cpp
+++ b/lib/Target/PowerPC/MCTargetDesc/PPCAsmBackend.cpp
@@ -29,9 +29,14 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
   case FK_Data_1:
   case FK_Data_2:
   case FK_Data_4:
+  case FK_Data_8:
+  case PPC::fixup_ppc_toc:
     return Value;
+  case PPC::fixup_ppc_lo14:
+  case PPC::fixup_ppc_toc16_ds:
+    return (Value & 0xffff) << 2;
   case PPC::fixup_ppc_brcond14:
-    return Value & 0x3ffc;
+    return Value & 0xfffc;
   case PPC::fixup_ppc_br24:
     return Value & 0x3fffffc;
 #if 0
@@ -41,6 +46,7 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
   case PPC::fixup_ppc_ha16:
     return ((Value >> 16) + ((Value & 0x8000) ? 1 : 0)) & 0xffff;
   case PPC::fixup_ppc_lo16:
+  case PPC::fixup_ppc_toc16:
     return Value & 0xffff;
   }
 }
@@ -72,7 +78,10 @@ public:
       { "fixup_ppc_brcond14",    16,     14,   MCFixupKindInfo::FKF_IsPCRel },
       { "fixup_ppc_lo16",        16,     16,   0 },
       { "fixup_ppc_ha16",        16,     16,   0 },
-      { "fixup_ppc_lo14",        16,     14,   0 }
+      { "fixup_ppc_lo14",        16,     14,   0 },
+      { "fixup_ppc_toc",          0,     64,   0 },
+      { "fixup_ppc_toc16",       16,     16,   0 },
+      { "fixup_ppc_toc16_ds",    16,     14,   0 }
     };
 
     if (Kind < FirstTargetFixupKind)
diff --git a/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp b/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp
index a197981..de3c352 100644
--- a/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp
+++ b/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp
@@ -11,6 +11,8 @@
 #include "MCTargetDesc/PPCMCTargetDesc.h"
 #include "llvm/MC/MCELFObjectWriter.h"
 #include "llvm/Support/ErrorHandling.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCValue.h"
 
 using namespace llvm;
 
@@ -21,9 +23,15 @@ namespace {
 
     virtual ~PPCELFObjectWriter();
   protected:
+    virtual unsigned getRelocTypeInner(const MCValue &Target,
+                                       const MCFixup &Fixup,
+                                       bool IsPCRel) const;
     virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
                                   bool IsPCRel, bool IsRelocWithSymbol,
                                   int64_t Addend) const;
+    virtual const MCSymbol *undefinedExplicitRelSym(const MCValue &Target,
+                                                    const MCFixup &Fixup,
+                                                    bool IsPCRel) const;
     virtual void adjustFixupOffset(const MCFixup &Fixup, uint64_t &RelocOffset);
   };
 }
@@ -36,11 +44,13 @@ PPCELFObjectWriter::PPCELFObjectWriter(bool Is64Bit, uint8_t OSABI)
 PPCELFObjectWriter::~PPCELFObjectWriter() {
 }
 
-unsigned PPCELFObjectWriter::GetRelocType(const MCValue &Target,
-                                             const MCFixup &Fixup,
-                                             bool IsPCRel,
-                                             bool IsRelocWithSymbol,
-                                             int64_t Addend) const {
+unsigned PPCELFObjectWriter::getRelocTypeInner(const MCValue &Target,
+                                               const MCFixup &Fixup,
+                                               bool IsPCRel) const
+{
+  MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
+    MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
+
   // determine the type of the relocation
   unsigned Type;
   if (IsPCRel) {
@@ -61,7 +71,7 @@ unsigned PPCELFObjectWriter::GetRelocType(const MCValue &Target,
       Type = ELF::R_PPC_ADDR24;
       break;
     case PPC::fixup_ppc_brcond14:
-      Type = ELF::R_PPC_ADDR14_BRTAKEN; // XXX: or BRNTAKEN?_
+      Type = ELF::R_PPC_ADDR14; // XXX: or BRNTAKEN?_
       break;
     case PPC::fixup_ppc_ha16:
       Type = ELF::R_PPC_ADDR16_HA;
@@ -72,6 +82,26 @@ unsigned PPCELFObjectWriter::GetRelocType(const MCValue &Target,
     case PPC::fixup_ppc_lo14:
       Type = ELF::R_PPC_ADDR14;
       break;
+    case PPC::fixup_ppc_toc:
+      Type = ELF::R_PPC64_TOC;
+      break;
+    case PPC::fixup_ppc_toc16:
+      Type = ELF::R_PPC64_TOC16;
+      break;
+    case PPC::fixup_ppc_toc16_ds:
+      Type = ELF::R_PPC64_TOC16_DS;
+      break;
+    case FK_Data_8:
+      switch (Modifier) {
+      default: llvm_unreachable("Unsupported Modifier");
+      case MCSymbolRefExpr::VK_PPC_TOC:
+        Type = ELF::R_PPC64_TOC;
+        break;
+      case MCSymbolRefExpr::VK_None:
+        Type = ELF::R_PPC64_ADDR64;
+	break;
+      }
+      break;
     case FK_Data_4:
       Type = ELF::R_PPC_ADDR32;
       break;
@@ -83,6 +113,34 @@ unsigned PPCELFObjectWriter::GetRelocType(const MCValue &Target,
   return Type;
 }
 
+unsigned PPCELFObjectWriter::GetRelocType(const MCValue &Target,
+                                          const MCFixup &Fixup,
+                                          bool IsPCRel,
+                                          bool IsRelocWithSymbol,
+                                          int64_t Addend) const {
+  return getRelocTypeInner(Target, Fixup, IsPCRel);
+}
+
+const MCSymbol *PPCELFObjectWriter::undefinedExplicitRelSym(const MCValue &Target,
+                                                            const MCFixup &Fixup,
+                                                            bool IsPCRel) const {
+  assert(Target.getSymA() && "SymA cannot be 0");
+  const MCSymbol &Symbol = Target.getSymA()->getSymbol().AliasedSymbol();
+
+  unsigned RelocType = getRelocTypeInner(Target, Fixup, IsPCRel);
+
+  // The .odp creation emits a relocation against the symbol ".TOC." which
+  // create a R_PPC64_TOC relocation. However the relocation symbol name
+  // in final object creation should be NULL, since the symbol does not
+  // really exist, it is just the reference to TOC base for the current
+  // object file.
+  bool EmitThisSym = RelocType != ELF::R_PPC64_TOC;
+
+  if (EmitThisSym && !Symbol.isTemporary())
+    return &Symbol;
+  return NULL;
+}
+
 void PPCELFObjectWriter::
 adjustFixupOffset(const MCFixup &Fixup, uint64_t &RelocOffset) {
   switch ((unsigned)Fixup.getKind()) {
diff --git a/lib/Target/PowerPC/MCTargetDesc/PPCFixupKinds.h b/lib/Target/PowerPC/MCTargetDesc/PPCFixupKinds.h
index b3c889e..37b265e 100644
--- a/lib/Target/PowerPC/MCTargetDesc/PPCFixupKinds.h
+++ b/lib/Target/PowerPC/MCTargetDesc/PPCFixupKinds.h
@@ -34,6 +34,16 @@ enum Fixups {
   /// fixup_ppc_lo14 - A 14-bit fixup corresponding to lo16(_foo) for instrs
   /// like 'std'.
   fixup_ppc_lo14,
+
+  /// fixup_ppc_toc - Insert value of TOC base (.TOC.).
+  fixup_ppc_toc,
+
+  /// fixup_ppc_toc16 - A 16-bit signed fixup relative to the TOC base.
+  fixup_ppc_toc16,
+
+  /// fixup_ppc_toc16_ds - A 14-bit signed fixup relative to the TOC base with
+  /// implied 2 zero bits
+  fixup_ppc_toc16_ds,
   
   // Marker
   LastTargetFixupKind,
diff --git a/lib/Target/PowerPC/MCTargetDesc/PPCMCCodeEmitter.cpp b/lib/Target/PowerPC/MCTargetDesc/PPCMCCodeEmitter.cpp
index 1fba5b8..635d6c8 100644
--- a/lib/Target/PowerPC/MCTargetDesc/PPCMCCodeEmitter.cpp
+++ b/lib/Target/PowerPC/MCTargetDesc/PPCMCCodeEmitter.cpp
@@ -15,7 +15,9 @@
 #include "MCTargetDesc/PPCBaseInfo.h"
 #include "MCTargetDesc/PPCFixupKinds.h"
 #include "llvm/MC/MCCodeEmitter.h"
+#include "llvm/MC/MCSubtargetInfo.h"
 #include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCInstrInfo.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -28,13 +30,25 @@ class PPCMCCodeEmitter : public MCCodeEmitter {
   PPCMCCodeEmitter(const PPCMCCodeEmitter &) LLVM_DELETED_FUNCTION;
   void operator=(const PPCMCCodeEmitter &) LLVM_DELETED_FUNCTION;
 
+  const MCSubtargetInfo &STI;
+  Triple TT;
+
 public:
   PPCMCCodeEmitter(const MCInstrInfo &mcii, const MCSubtargetInfo &sti,
-                   MCContext &ctx) {
+                   MCContext &ctx)
+    : STI(sti), TT(STI.getTargetTriple()) {
   }
   
   ~PPCMCCodeEmitter() {}
 
+  bool is64BitMode() const {
+    return (STI.getFeatureBits() & PPC::Feature64Bit) != 0;
+  }
+
+  bool isSVR4ABI() const {
+    return TT.isMacOSX() == 0;
+  }
+
   unsigned getDirectBrEncoding(const MCInst &MI, unsigned OpNo,
                                SmallVectorImpl<MCFixup> &Fixups) const;
   unsigned getCondBrEncoding(const MCInst &MI, unsigned OpNo,
@@ -140,8 +154,12 @@ unsigned PPCMCCodeEmitter::getMemRIEncoding(const MCInst &MI, unsigned OpNo,
     return (getMachineOpValue(MI, MO, Fixups) & 0xFFFF) | RegBits;
   
   // Add a fixup for the displacement field.
-  Fixups.push_back(MCFixup::Create(0, MO.getExpr(),
-                                   (MCFixupKind)PPC::fixup_ppc_lo16));
+  if (isSVR4ABI() && is64BitMode())
+    Fixups.push_back(MCFixup::Create(0, MO.getExpr(),
+                                     (MCFixupKind)PPC::fixup_ppc_toc16));
+  else
+    Fixups.push_back(MCFixup::Create(0, MO.getExpr(),
+                                     (MCFixupKind)PPC::fixup_ppc_lo16));
   return RegBits;
 }
 
@@ -158,8 +176,12 @@ unsigned PPCMCCodeEmitter::getMemRIXEncoding(const MCInst &MI, unsigned OpNo,
     return (getMachineOpValue(MI, MO, Fixups) & 0x3FFF) | RegBits;
   
   // Add a fixup for the branch target.
-  Fixups.push_back(MCFixup::Create(0, MO.getExpr(),
-                                   (MCFixupKind)PPC::fixup_ppc_lo14));
+  if (isSVR4ABI() && is64BitMode())
+    Fixups.push_back(MCFixup::Create(0, MO.getExpr(),
+                                     (MCFixupKind)PPC::fixup_ppc_toc16_ds));
+  else
+    Fixups.push_back(MCFixup::Create(0, MO.getExpr(),
+                                     (MCFixupKind)PPC::fixup_ppc_lo14));
   return RegBits;
 }