1 files changed, 172 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/RegAllocBase.cpp b/llvm/lib/CodeGen/RegAllocBase.cpp
new file mode 100644
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+++ b/llvm/lib/CodeGen/RegAllocBase.cpp
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+//===- RegAllocBase.cpp - Register Allocator Base Class -------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the RegAllocBase class which provides common functionality
+// for LiveIntervalUnion-based register allocators.
+//
+//===----------------------------------------------------------------------===//
+
+#include "RegAllocBase.h"
+#include "Spiller.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/CodeGen/LiveInterval.h"
+#include "llvm/CodeGen/LiveIntervals.h"
+#include "llvm/CodeGen/LiveRegMatrix.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGen/TargetRegisterInfo.h"
+#include "llvm/CodeGen/VirtRegMap.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/Timer.h"
+#include "llvm/Support/raw_ostream.h"
+#include <cassert>
+
+using namespace llvm;
+
+#define DEBUG_TYPE "regalloc"
+
+STATISTIC(NumNewQueued    , "Number of new live ranges queued");
+
+// Temporary verification option until we can put verification inside
+// MachineVerifier.
+static cl::opt<bool, true>
+    VerifyRegAlloc("verify-regalloc", cl::location(RegAllocBase::VerifyEnabled),
+                   cl::Hidden, cl::desc("Verify during register allocation"));
+
+const char RegAllocBase::TimerGroupName[] = "regalloc";
+const char RegAllocBase::TimerGroupDescription[] = "Register Allocation";
+bool RegAllocBase::VerifyEnabled = false;
+
+//===----------------------------------------------------------------------===//
+//                         RegAllocBase Implementation
+//===----------------------------------------------------------------------===//
+
+// Pin the vtable to this file.
+void RegAllocBase::anchor() {}
+
+void RegAllocBase::init(VirtRegMap &vrm,
+                        LiveIntervals &lis,
+                        LiveRegMatrix &mat) {
+  TRI = &vrm.getTargetRegInfo();
+  MRI = &vrm.getRegInfo();
+  VRM = &vrm;
+  LIS = &lis;
+  Matrix = &mat;
+  MRI->freezeReservedRegs(vrm.getMachineFunction());
+  RegClassInfo.runOnMachineFunction(vrm.getMachineFunction());
+}
+
+// Visit all the live registers. If they are already assigned to a physical
+// register, unify them with the corresponding LiveIntervalUnion, otherwise push
+// them on the priority queue for later assignment.
+void RegAllocBase::seedLiveRegs() {
+  NamedRegionTimer T("seed", "Seed Live Regs", TimerGroupName,
+                     TimerGroupDescription, TimePassesIsEnabled);
+  for (unsigned i = 0, e = MRI->getNumVirtRegs(); i != e; ++i) {
+    unsigned Reg = Register::index2VirtReg(i);
+    if (MRI->reg_nodbg_empty(Reg))
+      continue;
+    enqueue(&LIS->getInterval(Reg));
+  }
+}
+
+// Top-level driver to manage the queue of unassigned VirtRegs and call the
+// selectOrSplit implementation.
+void RegAllocBase::allocatePhysRegs() {
+  seedLiveRegs();
+
+  // Continue assigning vregs one at a time to available physical registers.
+  while (LiveInterval *VirtReg = dequeue()) {
+    assert(!VRM->hasPhys(VirtReg->reg) && "Register already assigned");
+
+    // Unused registers can appear when the spiller coalesces snippets.
+    if (MRI->reg_nodbg_empty(VirtReg->reg)) {
+      LLVM_DEBUG(dbgs() << "Dropping unused " << *VirtReg << '\n');
+      aboutToRemoveInterval(*VirtReg);
+      LIS->removeInterval(VirtReg->reg);
+      continue;
+    }
+
+    // Invalidate all interference queries, live ranges could have changed.
+    Matrix->invalidateVirtRegs();
+
+    // selectOrSplit requests the allocator to return an available physical
+    // register if possible and populate a list of new live intervals that
+    // result from splitting.
+    LLVM_DEBUG(dbgs() << "\nselectOrSplit "
+                      << TRI->getRegClassName(MRI->getRegClass(VirtReg->reg))
+                      << ':' << *VirtReg << " w=" << VirtReg->weight << '\n');
+
+    using VirtRegVec = SmallVector<unsigned, 4>;
+
+    VirtRegVec SplitVRegs;
+    unsigned AvailablePhysReg = selectOrSplit(*VirtReg, SplitVRegs);
+
+    if (AvailablePhysReg == ~0u) {
+      // selectOrSplit failed to find a register!
+      // Probably caused by an inline asm.
+      MachineInstr *MI = nullptr;
+      for (MachineRegisterInfo::reg_instr_iterator
+           I = MRI->reg_instr_begin(VirtReg->reg), E = MRI->reg_instr_end();
+           I != E; ) {
+        MI = &*(I++);
+        if (MI->isInlineAsm())
+          break;
+      }
+      if (MI && MI->isInlineAsm()) {
+        MI->emitError("inline assembly requires more registers than available");
+      } else if (MI) {
+        LLVMContext &Context =
+            MI->getParent()->getParent()->getMMI().getModule()->getContext();
+        Context.emitError("ran out of registers during register allocation");
+      } else {
+        report_fatal_error("ran out of registers during register allocation");
+      }
+      // Keep going after reporting the error.
+      VRM->assignVirt2Phys(VirtReg->reg,
+                 RegClassInfo.getOrder(MRI->getRegClass(VirtReg->reg)).front());
+      continue;
+    }
+
+    if (AvailablePhysReg)
+      Matrix->assign(*VirtReg, AvailablePhysReg);
+
+    for (unsigned Reg : SplitVRegs) {
+      assert(LIS->hasInterval(Reg));
+
+      LiveInterval *SplitVirtReg = &LIS->getInterval(Reg);
+      assert(!VRM->hasPhys(SplitVirtReg->reg) && "Register already assigned");
+      if (MRI->reg_nodbg_empty(SplitVirtReg->reg)) {
+        assert(SplitVirtReg->empty() && "Non-empty but used interval");
+        LLVM_DEBUG(dbgs() << "not queueing unused  " << *SplitVirtReg << '\n');
+        aboutToRemoveInterval(*SplitVirtReg);
+        LIS->removeInterval(SplitVirtReg->reg);
+        continue;
+      }
+      LLVM_DEBUG(dbgs() << "queuing new interval: " << *SplitVirtReg << "\n");
+      assert(Register::isVirtualRegister(SplitVirtReg->reg) &&
+             "expect split value in virtual register");
+      enqueue(SplitVirtReg);
+      ++NumNewQueued;
+    }
+  }
+}
+
+void RegAllocBase::postOptimization() {
+  spiller().postOptimization();
+  for (auto DeadInst : DeadRemats) {
+    LIS->RemoveMachineInstrFromMaps(*DeadInst);
+    DeadInst->eraseFromParent();
+  }
+  DeadRemats.clear();
+}