1 files changed, 88 insertions, 0 deletions
diff --git a/llvm/lib/Target/Mips/MipsMachineFunction.cpp b/llvm/lib/Target/Mips/MipsMachineFunction.cpp
index 86c90d6..5774905 100644
--- a/llvm/lib/Target/Mips/MipsMachineFunction.cpp
+++ b/llvm/lib/Target/Mips/MipsMachineFunction.cpp
@@ -51,6 +51,94 @@ unsigned MipsFunctionInfo::getGlobalBaseReg() {
   return GlobalBaseReg;
 }
 
+void MipsFunctionInfo::initGlobalBaseReg() {
+  if (!GlobalBaseReg)
+    return;
+
+  MachineBasicBlock &MBB = MF.front();
+  MachineBasicBlock::iterator I = MBB.begin();
+  MachineRegisterInfo &RegInfo = MF.getRegInfo();
+  const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
+  DebugLoc DL;
+  unsigned V0, V1;
+  const TargetRegisterClass *RC;
+  const MipsABIInfo &ABI =
+      static_cast<const MipsTargetMachine &>(MF.getTarget()).getABI();
+  RC = (ABI.IsN64()) ? &Mips::GPR64RegClass : &Mips::GPR32RegClass;
+
+  V0 = RegInfo.createVirtualRegister(RC);
+  V1 = RegInfo.createVirtualRegister(RC);
+
+  if (ABI.IsN64()) {
+    MF.getRegInfo().addLiveIn(Mips::T9_64);
+    MBB.addLiveIn(Mips::T9_64);
+
+    // lui $v0, %hi(%neg(%gp_rel(fname)))
+    // daddu $v1, $v0, $t9
+    // daddiu $globalbasereg, $v1, %lo(%neg(%gp_rel(fname)))
+    const GlobalValue *FName = &MF.getFunction();
+    BuildMI(MBB, I, DL, TII.get(Mips::LUi64), V0)
+        .addGlobalAddress(FName, 0, MipsII::MO_GPOFF_HI);
+    BuildMI(MBB, I, DL, TII.get(Mips::DADDu), V1).addReg(V0)
+        .addReg(Mips::T9_64);
+    BuildMI(MBB, I, DL, TII.get(Mips::DADDiu), GlobalBaseReg).addReg(V1)
+        .addGlobalAddress(FName, 0, MipsII::MO_GPOFF_LO);
+    return;
+  }
+
+  if (!MF.getTarget().isPositionIndependent()) {
+    // Set global register to __gnu_local_gp.
+    //
+    // lui   $v0, %hi(__gnu_local_gp)
+    // addiu $globalbasereg, $v0, %lo(__gnu_local_gp)
+    BuildMI(MBB, I, DL, TII.get(Mips::LUi), V0)
+        .addExternalSymbol("__gnu_local_gp", MipsII::MO_ABS_HI);
+    BuildMI(MBB, I, DL, TII.get(Mips::ADDiu), GlobalBaseReg).addReg(V0)
+        .addExternalSymbol("__gnu_local_gp", MipsII::MO_ABS_LO);
+    return;
+  }
+
+  MF.getRegInfo().addLiveIn(Mips::T9);
+  MBB.addLiveIn(Mips::T9);
+
+  if (ABI.IsN32()) {
+    // lui $v0, %hi(%neg(%gp_rel(fname)))
+    // addu $v1, $v0, $t9
+    // addiu $globalbasereg, $v1, %lo(%neg(%gp_rel(fname)))
+    const GlobalValue *FName = &MF.getFunction();
+    BuildMI(MBB, I, DL, TII.get(Mips::LUi), V0)
+        .addGlobalAddress(FName, 0, MipsII::MO_GPOFF_HI);
+    BuildMI(MBB, I, DL, TII.get(Mips::ADDu), V1).addReg(V0).addReg(Mips::T9);
+    BuildMI(MBB, I, DL, TII.get(Mips::ADDiu), GlobalBaseReg).addReg(V1)
+        .addGlobalAddress(FName, 0, MipsII::MO_GPOFF_LO);
+    return;
+  }
+
+  assert(ABI.IsO32());
+
+  // For O32 ABI, the following instruction sequence is emitted to initialize
+  // the global base register:
+  //
+  //  0. lui   $2, %hi(_gp_disp)
+  //  1. addiu $2, $2, %lo(_gp_disp)
+  //  2. addu  $globalbasereg, $2, $t9
+  //
+  // We emit only the last instruction here.
+  //
+  // GNU linker requires that the first two instructions appear at the beginning
+  // of a function and no instructions be inserted before or between them.
+  // The two instructions are emitted during lowering to MC layer in order to
+  // avoid any reordering.
+  //
+  // Register $2 (Mips::V0) is added to the list of live-in registers to ensure
+  // the value instruction 1 (addiu) defines is valid when instruction 2 (addu)
+  // reads it.
+  MF.getRegInfo().addLiveIn(Mips::V0);
+  MBB.addLiveIn(Mips::V0);
+  BuildMI(MBB, I, DL, TII.get(Mips::ADDu), GlobalBaseReg)
+      .addReg(Mips::V0).addReg(Mips::T9);
+}
+
 void MipsFunctionInfo::createEhDataRegsFI() {
   const TargetRegisterInfo &TRI = *MF.getSubtarget().getRegisterInfo();
   for (int I = 0; I < 4; ++I) {