1 files changed, 44 insertions, 16 deletions

diff --git a/llvm/lib/Target/X86/X86InstrInfo.cpp b/llvm/lib/Target/X86/X86InstrInfo.cpp
index b24c02922b7..d5577acde90 100644
--- a/llvm/lib/Target/X86/X86InstrInfo.cpp
+++ b/llvm/lib/Target/X86/X86InstrInfo.cpp
@@ -11239,7 +11239,9 @@ isSafeToMoveRegClassDefs(const TargetRegisterClass *RC) const {
 /// TODO: Eliminate this and move the code to X86MachineFunctionInfo.
 ///
 unsigned X86InstrInfo::getGlobalBaseReg(MachineFunction *MF) const {
-  assert(!Subtarget.is64Bit() &&
+  assert((!Subtarget.is64Bit() ||
+          MF->getTarget().getCodeModel() == CodeModel::Medium ||
+          MF->getTarget().getCodeModel() == CodeModel::Large) &&
          "X86-64 PIC uses RIP relative addressing");
 
   X86MachineFunctionInfo *X86FI = MF->getInfo<X86MachineFunctionInfo>();
@@ -11250,7 +11252,8 @@ unsigned X86InstrInfo::getGlobalBaseReg(MachineFunction *MF) const {
   // Create the register. The code to initialize it is inserted
   // later, by the CGBR pass (below).
   MachineRegisterInfo &RegInfo = MF->getRegInfo();
-  GlobalBaseReg = RegInfo.createVirtualRegister(&X86::GR32_NOSPRegClass);
+  GlobalBaseReg = RegInfo.createVirtualRegister(
+      Subtarget.is64Bit() ? &X86::GR64_NOSPRegClass : &X86::GR32_NOSPRegClass);
   X86FI->setGlobalBaseReg(GlobalBaseReg);
   return GlobalBaseReg;
 }
@@ -12624,9 +12627,10 @@ namespace {
         static_cast<const X86TargetMachine *>(&MF.getTarget());
       const X86Subtarget &STI = MF.getSubtarget<X86Subtarget>();
 
-      // Don't do anything if this is 64-bit as 64-bit PIC
-      // uses RIP relative addressing.
-      if (STI.is64Bit())
+      // Don't do anything in the 64-bit small and kernel code models. They use
+      // RIP-relative addressing for everything.
+      if (STI.is64Bit() && (TM->getCodeModel() == CodeModel::Small ||
+                            TM->getCodeModel() == CodeModel::Kernel))
         return false;
 
       // Only emit a global base reg in PIC mode.
@@ -12653,17 +12657,41 @@ namespace {
       else
         PC = GlobalBaseReg;
 
-      // Operand of MovePCtoStack is completely ignored by asm printer. It's
-      // only used in JIT code emission as displacement to pc.
-      BuildMI(FirstMBB, MBBI, DL, TII->get(X86::MOVPC32r), PC).addImm(0);
-
-      // If we're using vanilla 'GOT' PIC style, we should use relative addressing
-      // not to pc, but to _GLOBAL_OFFSET_TABLE_ external.
-      if (STI.isPICStyleGOT()) {
-        // Generate addl $__GLOBAL_OFFSET_TABLE_ + [.-piclabel], %some_register
-        BuildMI(FirstMBB, MBBI, DL, TII->get(X86::ADD32ri), GlobalBaseReg)
-          .addReg(PC).addExternalSymbol("_GLOBAL_OFFSET_TABLE_",
-                                        X86II::MO_GOT_ABSOLUTE_ADDRESS);
+      if (STI.is64Bit()) {
+        if (TM->getCodeModel() == CodeModel::Medium) {
+          // In the medium code model, use a RIP-relative LEA to materialize the
+          // GOT.
+          BuildMI(FirstMBB, MBBI, DL, TII->get(X86::LEA64r), PC)
+              .addReg(X86::RIP)
+              .addImm(0)
+              .addReg(0)
+              .addExternalSymbol("_GLOBAL_OFFSET_TABLE_")
+              .addReg(0);
+        } else if (TM->getCodeModel() == CodeModel::Large) {
+          // Loading the GOT in the large code model requires math with labels,
+          // so we use a pseudo instruction and expand it during MC emission.
+          unsigned Scratch = RegInfo.createVirtualRegister(&X86::GR64RegClass);
+          BuildMI(FirstMBB, MBBI, DL, TII->get(X86::MOVGOT64r), PC)
+              .addReg(Scratch, RegState::Undef | RegState::Define)
+              .addExternalSymbol("_GLOBAL_OFFSET_TABLE_");
+        } else {
+          llvm_unreachable("unexpected code model");
+        }
+      } else {
+        // Operand of MovePCtoStack is completely ignored by asm printer. It's
+        // only used in JIT code emission as displacement to pc.
+        BuildMI(FirstMBB, MBBI, DL, TII->get(X86::MOVPC32r), PC).addImm(0);
+
+        // If we're using vanilla 'GOT' PIC style, we should use relative
+        // addressing not to pc, but to _GLOBAL_OFFSET_TABLE_ external.
+        if (STI.isPICStyleGOT()) {
+          // Generate addl $__GLOBAL_OFFSET_TABLE_ + [.-piclabel],
+          // %some_register
+          BuildMI(FirstMBB, MBBI, DL, TII->get(X86::ADD32ri), GlobalBaseReg)
+              .addReg(PC)
+              .addExternalSymbol("_GLOBAL_OFFSET_TABLE_",
+                                 X86II::MO_GOT_ABSOLUTE_ADDRESS);
+        }
       }
 
       return true;