forked from OSchip/llvm-project
147 lines
4.9 KiB
C++
147 lines
4.9 KiB
C++
//===-- SystemZLDCleanup.cpp - Clean up local-dynamic TLS accesses --------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This pass combines multiple accesses to local-dynamic TLS variables so that
|
|
// the TLS base address for the module is only fetched once per execution path
|
|
// through the function.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "SystemZMachineFunctionInfo.h"
|
|
#include "SystemZTargetMachine.h"
|
|
#include "llvm/CodeGen/MachineDominators.h"
|
|
#include "llvm/CodeGen/MachineFunctionPass.h"
|
|
#include "llvm/CodeGen/MachineInstrBuilder.h"
|
|
#include "llvm/CodeGen/MachineRegisterInfo.h"
|
|
#include "llvm/Target/TargetInstrInfo.h"
|
|
#include "llvm/Target/TargetMachine.h"
|
|
#include "llvm/Target/TargetRegisterInfo.h"
|
|
|
|
using namespace llvm;
|
|
|
|
namespace {
|
|
|
|
class SystemZLDCleanup : public MachineFunctionPass {
|
|
public:
|
|
static char ID;
|
|
SystemZLDCleanup(const SystemZTargetMachine &tm)
|
|
: MachineFunctionPass(ID), TII(nullptr), MF(nullptr) {}
|
|
|
|
StringRef getPassName() const override {
|
|
return "SystemZ Local Dynamic TLS Access Clean-up";
|
|
}
|
|
|
|
bool runOnMachineFunction(MachineFunction &MF) override;
|
|
void getAnalysisUsage(AnalysisUsage &AU) const override;
|
|
|
|
private:
|
|
bool VisitNode(MachineDomTreeNode *Node, unsigned TLSBaseAddrReg);
|
|
MachineInstr *ReplaceTLSCall(MachineInstr *I, unsigned TLSBaseAddrReg);
|
|
MachineInstr *SetRegister(MachineInstr *I, unsigned *TLSBaseAddrReg);
|
|
|
|
const SystemZInstrInfo *TII;
|
|
MachineFunction *MF;
|
|
};
|
|
|
|
char SystemZLDCleanup::ID = 0;
|
|
|
|
} // end anonymous namespace
|
|
|
|
FunctionPass *llvm::createSystemZLDCleanupPass(SystemZTargetMachine &TM) {
|
|
return new SystemZLDCleanup(TM);
|
|
}
|
|
|
|
void SystemZLDCleanup::getAnalysisUsage(AnalysisUsage &AU) const {
|
|
AU.setPreservesCFG();
|
|
AU.addRequired<MachineDominatorTree>();
|
|
MachineFunctionPass::getAnalysisUsage(AU);
|
|
}
|
|
|
|
bool SystemZLDCleanup::runOnMachineFunction(MachineFunction &F) {
|
|
if (skipFunction(*F.getFunction()))
|
|
return false;
|
|
|
|
TII = static_cast<const SystemZInstrInfo *>(F.getSubtarget().getInstrInfo());
|
|
MF = &F;
|
|
|
|
SystemZMachineFunctionInfo* MFI = F.getInfo<SystemZMachineFunctionInfo>();
|
|
if (MFI->getNumLocalDynamicTLSAccesses() < 2) {
|
|
// No point folding accesses if there isn't at least two.
|
|
return false;
|
|
}
|
|
|
|
MachineDominatorTree *DT = &getAnalysis<MachineDominatorTree>();
|
|
return VisitNode(DT->getRootNode(), 0);
|
|
}
|
|
|
|
// Visit the dominator subtree rooted at Node in pre-order.
|
|
// If TLSBaseAddrReg is non-null, then use that to replace any
|
|
// TLS_LDCALL instructions. Otherwise, create the register
|
|
// when the first such instruction is seen, and then use it
|
|
// as we encounter more instructions.
|
|
bool SystemZLDCleanup::VisitNode(MachineDomTreeNode *Node,
|
|
unsigned TLSBaseAddrReg) {
|
|
MachineBasicBlock *BB = Node->getBlock();
|
|
bool Changed = false;
|
|
|
|
// Traverse the current block.
|
|
for (auto I = BB->begin(), E = BB->end(); I != E; ++I) {
|
|
switch (I->getOpcode()) {
|
|
case SystemZ::TLS_LDCALL:
|
|
if (TLSBaseAddrReg)
|
|
I = ReplaceTLSCall(&*I, TLSBaseAddrReg);
|
|
else
|
|
I = SetRegister(&*I, &TLSBaseAddrReg);
|
|
Changed = true;
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Visit the children of this block in the dominator tree.
|
|
for (auto I = Node->begin(), E = Node->end(); I != E; ++I)
|
|
Changed |= VisitNode(*I, TLSBaseAddrReg);
|
|
|
|
return Changed;
|
|
}
|
|
|
|
// Replace the TLS_LDCALL instruction I with a copy from TLSBaseAddrReg,
|
|
// returning the new instruction.
|
|
MachineInstr *SystemZLDCleanup::ReplaceTLSCall(MachineInstr *I,
|
|
unsigned TLSBaseAddrReg) {
|
|
// Insert a Copy from TLSBaseAddrReg to R2.
|
|
MachineInstr *Copy = BuildMI(*I->getParent(), I, I->getDebugLoc(),
|
|
TII->get(TargetOpcode::COPY), SystemZ::R2D)
|
|
.addReg(TLSBaseAddrReg);
|
|
|
|
// Erase the TLS_LDCALL instruction.
|
|
I->eraseFromParent();
|
|
|
|
return Copy;
|
|
}
|
|
|
|
// Create a virtual register in *TLSBaseAddrReg, and populate it by
|
|
// inserting a copy instruction after I. Returns the new instruction.
|
|
MachineInstr *SystemZLDCleanup::SetRegister(MachineInstr *I,
|
|
unsigned *TLSBaseAddrReg) {
|
|
// Create a virtual register for the TLS base address.
|
|
MachineRegisterInfo &RegInfo = MF->getRegInfo();
|
|
*TLSBaseAddrReg = RegInfo.createVirtualRegister(&SystemZ::GR64BitRegClass);
|
|
|
|
// Insert a copy from R2 to TLSBaseAddrReg.
|
|
MachineInstr *Next = I->getNextNode();
|
|
MachineInstr *Copy = BuildMI(*I->getParent(), Next, I->getDebugLoc(),
|
|
TII->get(TargetOpcode::COPY), *TLSBaseAddrReg)
|
|
.addReg(SystemZ::R2D);
|
|
|
|
return Copy;
|
|
}
|
|
|