[MIPS GlobalISel] Select global address

Select G_GLOBAL_VALUE for position dependent code.

Patch by Petar Avramovic.

Differential Revision: https://reviews.llvm.org/D49803

llvm-svn: 338499

3 files changed, 31 insertions, 0 deletions

diff --git a/llvm/lib/Target/Mips/MipsInstructionSelector.cpp b/llvm/lib/Target/Mips/MipsInstructionSelector.cpp
index af0ac006bc9..6c5b83021f7 100644
--- a/llvm/lib/Target/Mips/MipsInstructionSelector.cpp
+++ b/llvm/lib/Target/Mips/MipsInstructionSelector.cpp
@@ -166,6 +166,33 @@ bool MipsInstructionSelector::select(MachineInstr &I,
     I.eraseFromParent();
     return true;
   }
+  case G_GLOBAL_VALUE: {
+    if (MF.getTarget().isPositionIndependent())
+      return false;
+
+    const llvm::GlobalValue *GVal = I.getOperand(1).getGlobal();
+    unsigned LUiReg = MRI.createVirtualRegister(&Mips::GPR32RegClass);
+    MachineInstr *LUi, *ADDiu;
+
+    LUi = BuildMI(MBB, I, I.getDebugLoc(), TII.get(Mips::LUi))
+              .addDef(LUiReg)
+              .addGlobalAddress(GVal);
+    LUi->getOperand(1).setTargetFlags(MipsII::MO_ABS_HI);
+
+    ADDiu = BuildMI(MBB, I, I.getDebugLoc(), TII.get(Mips::ADDiu))
+                .addDef(I.getOperand(0).getReg())
+                .addUse(LUiReg)
+                .addGlobalAddress(GVal);
+    ADDiu->getOperand(2).setTargetFlags(MipsII::MO_ABS_LO);
+
+    if (!constrainSelectedInstRegOperands(*LUi, TII, TRI, RBI))
+      return false;
+    if (!constrainSelectedInstRegOperands(*ADDiu, TII, TRI, RBI))
+      return false;
+
+    I.eraseFromParent();
+    return true;
+  }
 
   default:
     return false;
diff --git a/llvm/lib/Target/Mips/MipsLegalizerInfo.cpp b/llvm/lib/Target/Mips/MipsLegalizerInfo.cpp
index da6f9dabdaa..fb259516be0 100644
--- a/llvm/lib/Target/Mips/MipsLegalizerInfo.cpp
+++ b/llvm/lib/Target/Mips/MipsLegalizerInfo.cpp
@@ -36,6 +36,9 @@ MipsLegalizerInfo::MipsLegalizerInfo(const MipsSubtarget &ST) {
   getActionDefinitionsBuilder(G_FRAME_INDEX)
       .legalFor({p0});
 
+  getActionDefinitionsBuilder(G_GLOBAL_VALUE)
+      .legalFor({p0});
+
   computeTables();
   verify(*ST.getInstrInfo());
 }
diff --git a/llvm/lib/Target/Mips/MipsRegisterBankInfo.cpp b/llvm/lib/Target/Mips/MipsRegisterBankInfo.cpp
index cef21f44720..35113507921 100644
--- a/llvm/lib/Target/Mips/MipsRegisterBankInfo.cpp
+++ b/llvm/lib/Target/Mips/MipsRegisterBankInfo.cpp
@@ -88,6 +88,7 @@ MipsRegisterBankInfo::getInstrMapping(const MachineInstr &MI) const {
     break;
   case G_CONSTANT:
   case G_FRAME_INDEX:
+  case G_GLOBAL_VALUE:
     OperandsMapping =
         getOperandsMapping({&Mips::ValueMappings[Mips::GPRIdx], nullptr});
     break;