[mips] N64 static relocation model support

This patch makes one change to GOT handling and two changes to N64's
relocation model handling. Furthermore, the jumptable encodings have
been corrected for static N64.

Big GOT handling is now done via a new SDNode MipsGotHi - this node is
unconditionally lowered to an lui instruction.

The first change to N64's relocation handling is the lifting of the
restriction that N64 always uses PIC. Now it is possible to target static
environments.

The second change adds support for 64 bit symbols and enables them by
default. Previously N64 had patterns for sym32 mode only. In this mode all
symbols are assumed to have 32 bit addresses. sym32 mode support
is selectable with attribute 'sym32'. A follow on patch for clang will
add the necessary frontend parameter.

This partially resolves PR/23485.

Thanks to Brooks Davis for reporting the issue!

Reviewers: dsanders, seanbruno, zoran.jovanovic, vkalintiris

Differential Revision: https://reviews.llvm.org/D23652

llvm-svn: 293164

1 files changed, 26 insertions, 17 deletions

diff --git a/llvm/lib/Target/Mips/MipsISelLowering.cpp b/llvm/lib/Target/Mips/MipsISelLowering.cpp
index 9c511bd7782..f0f2424f722 100644
--- a/llvm/lib/Target/Mips/MipsISelLowering.cpp
+++ b/llvm/lib/Target/Mips/MipsISelLowering.cpp
@@ -112,8 +112,11 @@ const char *MipsTargetLowering::getTargetNodeName(unsigned Opcode) const {
   case MipsISD::FIRST_NUMBER:      break;
   case MipsISD::JmpLink:           return "MipsISD::JmpLink";
   case MipsISD::TailCall:          return "MipsISD::TailCall";
+  case MipsISD::Highest:           return "MipsISD::Highest";
+  case MipsISD::Higher:            return "MipsISD::Higher";
   case MipsISD::Hi:                return "MipsISD::Hi";
   case MipsISD::Lo:                return "MipsISD::Lo";
+  case MipsISD::GotHi:             return "MipsISD::GotHi";
   case MipsISD::GPRel:             return "MipsISD::GPRel";
   case MipsISD::ThreadPointer:     return "MipsISD::ThreadPointer";
   case MipsISD::Ret:               return "MipsISD::Ret";
@@ -1733,7 +1736,7 @@ SDValue MipsTargetLowering::lowerGlobalAddress(SDValue Op,
   GlobalAddressSDNode *N = cast<GlobalAddressSDNode>(Op);
   const GlobalValue *GV = N->getGlobal();
 
-  if (!isPositionIndependent() && !ABI.IsN64()) {
+  if (!isPositionIndependent()) {
     const MipsTargetObjectFile *TLOF =
         static_cast<const MipsTargetObjectFile *>(
             getTargetMachine().getObjFileLowering());
@@ -1742,8 +1745,10 @@ SDValue MipsTargetLowering::lowerGlobalAddress(SDValue Op,
       // %gp_rel relocation
       return getAddrGPRel(N, SDLoc(N), Ty, DAG);
 
-    // %hi/%lo relocation
-    return getAddrNonPIC(N, SDLoc(N), Ty, DAG);
+                                 // %hi/%lo relocation
+    return Subtarget.hasSym32() ? getAddrNonPIC(N, SDLoc(N), Ty, DAG)
+                                 // %highest/%higher/%hi/%lo relocation
+                                 : getAddrNonPICSym64(N, SDLoc(N), Ty, DAG);
   }
 
   // Every other architecture would use shouldAssumeDSOLocal in here, but
@@ -1777,8 +1782,9 @@ SDValue MipsTargetLowering::lowerBlockAddress(SDValue Op,
   BlockAddressSDNode *N = cast<BlockAddressSDNode>(Op);
   EVT Ty = Op.getValueType();
 
-  if (!isPositionIndependent() && !ABI.IsN64())
-    return getAddrNonPIC(N, SDLoc(N), Ty, DAG);
+  if (!isPositionIndependent())
+    return Subtarget.hasSym32() ? getAddrNonPIC(N, SDLoc(N), Ty, DAG)
+                                : getAddrNonPICSym64(N, SDLoc(N), Ty, DAG);
 
   return getAddrLocal(N, SDLoc(N), Ty, DAG, ABI.IsN32() || ABI.IsN64());
 }
@@ -1870,8 +1876,9 @@ lowerJumpTable(SDValue Op, SelectionDAG &DAG) const
   JumpTableSDNode *N = cast<JumpTableSDNode>(Op);
   EVT Ty = Op.getValueType();
 
-  if (!isPositionIndependent() && !ABI.IsN64())
-    return getAddrNonPIC(N, SDLoc(N), Ty, DAG);
+  if (!isPositionIndependent())
+    return Subtarget.hasSym32() ? getAddrNonPIC(N, SDLoc(N), Ty, DAG)
+                                : getAddrNonPICSym64(N, SDLoc(N), Ty, DAG);
 
   return getAddrLocal(N, SDLoc(N), Ty, DAG, ABI.IsN32() || ABI.IsN64());
 }
@@ -1882,7 +1889,7 @@ lowerConstantPool(SDValue Op, SelectionDAG &DAG) const
   ConstantPoolSDNode *N = cast<ConstantPoolSDNode>(Op);
   EVT Ty = Op.getValueType();
 
-  if (!isPositionIndependent() && !ABI.IsN64()) {
+  if (!isPositionIndependent()) {
     const MipsTargetObjectFile *TLOF =
         static_cast<const MipsTargetObjectFile *>(
             getTargetMachine().getObjFileLowering());
@@ -1892,10 +1899,11 @@ lowerConstantPool(SDValue Op, SelectionDAG &DAG) const
       // %gp_rel relocation
       return getAddrGPRel(N, SDLoc(N), Ty, DAG);
 
-    return getAddrNonPIC(N, SDLoc(N), Ty, DAG);
+    return Subtarget.hasSym32() ? getAddrNonPIC(N, SDLoc(N), Ty, DAG)
+                                : getAddrNonPICSym64(N, SDLoc(N), Ty, DAG);
   }
 
-  return getAddrLocal(N, SDLoc(N), Ty, DAG, ABI.IsN32() || ABI.IsN64());
+ return getAddrLocal(N, SDLoc(N), Ty, DAG, ABI.IsN32() || ABI.IsN64());
 }
 
 SDValue MipsTargetLowering::lowerVASTART(SDValue Op, SelectionDAG &DAG) const {
@@ -2796,14 +2804,13 @@ MipsTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
   // If the callee is a GlobalAddress/ExternalSymbol node (quite common, every
   // direct call is) turn it into a TargetGlobalAddress/TargetExternalSymbol
   // node so that legalize doesn't hack it.
-  bool IsPICCall = (ABI.IsN64() || IsPIC); // true if calls are translated to
-                                           // jalr $25
+
   SDValue CalleeLo;
   EVT Ty = Callee.getValueType();
   bool GlobalOrExternal = false, IsCallReloc = false;
 
   if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee)) {
-    if (IsPICCall) {
+    if (IsPIC) {
       const GlobalValue *Val = G->getGlobal();
       InternalLinkage = Val->hasInternalLinkage();
 
@@ -2828,7 +2835,7 @@ MipsTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
   else if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(Callee)) {
     const char *Sym = S->getSymbol();
 
-    if (!ABI.IsN64() && !IsPIC) // !N64 && static
+    if (!IsPIC) // static
       Callee = DAG.getTargetExternalSymbol(
           Sym, getPointerTy(DAG.getDataLayout()), MipsII::MO_NO_FLAG);
     else if (LargeGOT) {
@@ -2836,7 +2843,7 @@ MipsTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
                                      MipsII::MO_CALL_LO16, Chain,
                                      FuncInfo->callPtrInfo(Sym));
       IsCallReloc = true;
-    } else { // N64 || PIC
+    } else { // PIC
       Callee = getAddrGlobal(S, DL, Ty, DAG, MipsII::MO_GOT_CALL, Chain,
                              FuncInfo->callPtrInfo(Sym));
       IsCallReloc = true;
@@ -2848,7 +2855,7 @@ MipsTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
   SmallVector<SDValue, 8> Ops(1, Chain);
   SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
 
-  getOpndList(Ops, RegsToPass, IsPICCall, GlobalOrExternal, InternalLinkage,
+  getOpndList(Ops, RegsToPass, IsPIC, GlobalOrExternal, InternalLinkage,
               IsCallReloc, CLI, Callee, Chain);
 
   if (IsTailCall) {
@@ -3683,7 +3690,9 @@ bool MipsTargetLowering::isFPImmLegal(const APFloat &Imm, EVT VT) const {
 }
 
 unsigned MipsTargetLowering::getJumpTableEncoding() const {
-  if (ABI.IsN64())
+
+  // FIXME: For space reasons this should be: EK_GPRel32BlockAddress.
+  if (ABI.IsN64() && isPositionIndependent())
     return MachineJumpTableInfo::EK_GPRel64BlockAddress;
 
   return TargetLowering::getJumpTableEncoding();