[arm-fast-isel] Add support for ELF PIC.
This is a preliminary step towards ELF support; currently ARMFastISel hasn't
been used for ELF object files yet.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164759 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMFastISel.cpp b/lib/Target/ARM/ARMFastISel.cpp
index f7f6b5d..8933a02 100644
--- a/lib/Target/ARM/ARMFastISel.cpp
+++ b/lib/Target/ARM/ARMFastISel.cpp
@@ -194,6 +194,7 @@
unsigned ARMMoveToFPReg(EVT VT, unsigned SrcReg);
unsigned ARMMoveToIntReg(EVT VT, unsigned SrcReg);
unsigned ARMSelectCallOp(bool UseReg);
+ unsigned ARMLowerPICELF(const GlobalValue *GV, unsigned Align, EVT VT);
// Call handling routines.
private:
@@ -648,6 +649,9 @@
Align = TD.getTypeAllocSize(GV->getType());
}
+ if (Subtarget->isTargetELF() && RelocM == Reloc::PIC_)
+ return ARMLowerPICELF(GV, Align, VT);
+
// Grab index.
unsigned PCAdj = (RelocM != Reloc::PIC_) ? 0 :
(Subtarget->isThumb() ? 4 : 8);
@@ -2796,6 +2800,47 @@
return true;
}
+unsigned ARMFastISel::ARMLowerPICELF(const GlobalValue *GV,
+ unsigned Align, EVT VT) {
+ bool UseGOTOFF = GV->hasLocalLinkage() || GV->hasHiddenVisibility();
+ ARMConstantPoolConstant *CPV =
+ ARMConstantPoolConstant::Create(GV, UseGOTOFF ? ARMCP::GOTOFF : ARMCP::GOT);
+ unsigned Idx = MCP.getConstantPoolIndex(CPV, Align);
+
+ unsigned Opc;
+ unsigned DestReg1 = createResultReg(TLI.getRegClassFor(VT));
+ // Load value.
+ if (isThumb2) {
+ AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
+ TII.get(ARM::t2LDRpci), DestReg1)
+ .addConstantPoolIndex(Idx));
+ Opc = UseGOTOFF ? ARM::t2ADDrr : ARM::t2LDRs;
+ } else {
+ // The extra immediate is for addrmode2.
+ AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt,
+ DL, TII.get(ARM::LDRcp), DestReg1)
+ .addConstantPoolIndex(Idx).addImm(0));
+ Opc = UseGOTOFF ? ARM::ADDrr : ARM::LDRrs;
+ }
+
+ unsigned GlobalBaseReg = AFI->getGlobalBaseReg();
+ if (GlobalBaseReg == 0) {
+ GlobalBaseReg = MRI.createVirtualRegister(TLI.getRegClassFor(VT));
+ AFI->setGlobalBaseReg(GlobalBaseReg);
+ }
+
+ unsigned DestReg2 = createResultReg(TLI.getRegClassFor(VT));
+ MachineInstrBuilder MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt,
+ DL, TII.get(Opc), DestReg2)
+ .addReg(DestReg1)
+ .addReg(GlobalBaseReg);
+ if (!UseGOTOFF)
+ MIB.addImm(0);
+ AddOptionalDefs(MIB);
+
+ return DestReg2;
+}
+
namespace llvm {
FastISel *ARM::createFastISel(FunctionLoweringInfo &funcInfo,
const TargetLibraryInfo *libInfo) {