Imported Upstream version 5.18.0.207

Former-commit-id: 3b152f462918d427ce18620a2cbe4f8b79650449

external/llvm/lib/Target/AArch64/AArch64CleanupLocalDynamicTLSPass.cpp

@@ -1,150 +0,0 @@
-//===-- AArch64CleanupLocalDynamicTLSPass.cpp ---------------------*- C++ -*-=//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// Local-dynamic access to thread-local variables proceeds in three stages.
-//
-// 1. The offset of this Module's thread-local area from TPIDR_EL0 is calculated
-//    in much the same way as a general-dynamic TLS-descriptor access against
-//    the special symbol _TLS_MODULE_BASE.
-// 2. The variable's offset from _TLS_MODULE_BASE_ is calculated using
-//    instructions with "dtprel" modifiers.
-// 3. These two are added, together with TPIDR_EL0, to obtain the variable's
-//    true address.
-//
-// This is only better than general-dynamic access to the variable if two or
-// more of the first stage TLS-descriptor calculations can be combined. This
-// pass looks through a function and performs such combinations.
-//
-//===----------------------------------------------------------------------===//
-#include "AArch64.h"
-#include "AArch64InstrInfo.h"
-#include "AArch64MachineFunctionInfo.h"
-#include "llvm/CodeGen/MachineDominators.h"
-#include "llvm/CodeGen/MachineFunction.h"
-#include "llvm/CodeGen/MachineFunctionPass.h"
-#include "llvm/CodeGen/MachineInstrBuilder.h"
-#include "llvm/CodeGen/MachineRegisterInfo.h"
-using namespace llvm;
-
-#define TLSCLEANUP_PASS_NAME "AArch64 Local Dynamic TLS Access Clean-up"
-
-namespace {
-struct LDTLSCleanup : public MachineFunctionPass {
-  static char ID;
-  LDTLSCleanup() : MachineFunctionPass(ID) {
-    initializeLDTLSCleanupPass(*PassRegistry::getPassRegistry());
-  }
-
-  bool runOnMachineFunction(MachineFunction &MF) override {
-    if (skipFunction(MF.getFunction()))
-      return false;
-
-    AArch64FunctionInfo *AFI = MF.getInfo<AArch64FunctionInfo>();
-    if (AFI->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_base_addr instructions. Otherwise, create the register
-  // when the first such instruction is seen, and then use it
-  // as we encounter more instructions.
-  bool VisitNode(MachineDomTreeNode *Node, unsigned TLSBaseAddrReg) {
-    MachineBasicBlock *BB = Node->getBlock();
-    bool Changed = false;
-
-    // Traverse the current block.
-    for (MachineBasicBlock::iterator I = BB->begin(), E = BB->end(); I != E;
-         ++I) {
-      switch (I->getOpcode()) {
-      case AArch64::TLSDESC_CALLSEQ:
-        // Make sure it's a local dynamic access.
-        if (!I->getOperand(0).isSymbol() ||
-            strcmp(I->getOperand(0).getSymbolName(), "_TLS_MODULE_BASE_"))
-          break;
-
-        if (TLSBaseAddrReg)
-          I = replaceTLSBaseAddrCall(*I, TLSBaseAddrReg);
-        else
-          I = setRegister(*I, &TLSBaseAddrReg);
-        Changed = true;
-        break;
-      default:
-        break;
-      }
-    }
-
-    // Visit the children of this block in the dominator tree.
-    for (MachineDomTreeNode *N : *Node) {
-      Changed |= VisitNode(N, TLSBaseAddrReg);
-    }
-
-    return Changed;
-  }
-
-  // Replace the TLS_base_addr instruction I with a copy from
-  // TLSBaseAddrReg, returning the new instruction.
-  MachineInstr *replaceTLSBaseAddrCall(MachineInstr &I,
-                                       unsigned TLSBaseAddrReg) {
-    MachineFunction *MF = I.getParent()->getParent();
-    const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
-
-    // Insert a Copy from TLSBaseAddrReg to x0, which is where the rest of the
-    // code sequence assumes the address will be.
-    MachineInstr *Copy = BuildMI(*I.getParent(), I, I.getDebugLoc(),
-                                 TII->get(TargetOpcode::COPY), AArch64::X0)
-                             .addReg(TLSBaseAddrReg);
-
-    // Erase the TLS_base_addr 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 *setRegister(MachineInstr &I, unsigned *TLSBaseAddrReg) {
-    MachineFunction *MF = I.getParent()->getParent();
-    const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
-
-    // Create a virtual register for the TLS base address.
-    MachineRegisterInfo &RegInfo = MF->getRegInfo();
-    *TLSBaseAddrReg = RegInfo.createVirtualRegister(&AArch64::GPR64RegClass);
-
-    // Insert a copy from X0 to TLSBaseAddrReg for later.
-    MachineInstr *Copy =
-        BuildMI(*I.getParent(), ++I.getIterator(), I.getDebugLoc(),
-                TII->get(TargetOpcode::COPY), *TLSBaseAddrReg)
-            .addReg(AArch64::X0);
-
-    return Copy;
-  }
-
-  StringRef getPassName() const override { return TLSCLEANUP_PASS_NAME; }
-
-  void getAnalysisUsage(AnalysisUsage &AU) const override {
-    AU.setPreservesCFG();
-    AU.addRequired<MachineDominatorTree>();
-    MachineFunctionPass::getAnalysisUsage(AU);
-  }
-};
-}
-
-INITIALIZE_PASS(LDTLSCleanup, "aarch64-local-dynamic-tls-cleanup",
-                TLSCLEANUP_PASS_NAME, false, false)
-
-char LDTLSCleanup::ID = 0;
-FunctionPass *llvm::createAArch64CleanupLocalDynamicTLSPass() {
-  return new LDTLSCleanup();
-}