1 files changed, 170 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/StackMapLivenessAnalysis.cpp b/llvm/lib/CodeGen/StackMapLivenessAnalysis.cpp
new file mode 100644
index 000000000000..fb2abf3daa7f
--- /dev/null
+++ b/llvm/lib/CodeGen/StackMapLivenessAnalysis.cpp
@@ -0,0 +1,170 @@
+//===-- StackMapLivenessAnalysis.cpp - StackMap live Out Analysis ----------===//
+//
+// 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 implements the StackMap Liveness analysis pass. The pass calculates
+// the liveness for each basic block in a function and attaches the register
+// live-out information to a stackmap or patchpoint intrinsic if present.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/Statistic.h"
+#include "llvm/CodeGen/LivePhysRegs.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/CodeGen/TargetSubtargetInfo.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+
+#define DEBUG_TYPE "stackmaps"
+
+static cl::opt<bool> EnablePatchPointLiveness(
+    "enable-patchpoint-liveness", cl::Hidden, cl::init(true),
+    cl::desc("Enable PatchPoint Liveness Analysis Pass"));
+
+STATISTIC(NumStackMapFuncVisited, "Number of functions visited");
+STATISTIC(NumStackMapFuncSkipped, "Number of functions skipped");
+STATISTIC(NumBBsVisited,          "Number of basic blocks visited");
+STATISTIC(NumBBsHaveNoStackmap,   "Number of basic blocks with no stackmap");
+STATISTIC(NumStackMaps,           "Number of StackMaps visited");
+
+namespace {
+/// This pass calculates the liveness information for each basic block in
+/// a function and attaches the register live-out information to a patchpoint
+/// intrinsic if present.
+///
+/// This pass can be disabled via the -enable-patchpoint-liveness=false flag.
+/// The pass skips functions that don't have any patchpoint intrinsics. The
+/// information provided by this pass is optional and not required by the
+/// aformentioned intrinsic to function.
+class StackMapLiveness : public MachineFunctionPass {
+  const TargetRegisterInfo *TRI;
+  LivePhysRegs LiveRegs;
+
+public:
+  static char ID;
+
+  /// Default construct and initialize the pass.
+  StackMapLiveness();
+
+  /// Tell the pass manager which passes we depend on and what
+  /// information we preserve.
+  void getAnalysisUsage(AnalysisUsage &AU) const override;
+
+  MachineFunctionProperties getRequiredProperties() const override {
+    return MachineFunctionProperties().set(
+        MachineFunctionProperties::Property::NoVRegs);
+  }
+
+  /// Calculate the liveness information for the given machine function.
+  bool runOnMachineFunction(MachineFunction &MF) override;
+
+private:
+  /// Performs the actual liveness calculation for the function.
+  bool calculateLiveness(MachineFunction &MF);
+
+  /// Add the current register live set to the instruction.
+  void addLiveOutSetToMI(MachineFunction &MF, MachineInstr &MI);
+
+  /// Create a register mask and initialize it with the registers from
+  /// the register live set.
+  uint32_t *createRegisterMask(MachineFunction &MF) const;
+};
+} // namespace
+
+char StackMapLiveness::ID = 0;
+char &llvm::StackMapLivenessID = StackMapLiveness::ID;
+INITIALIZE_PASS(StackMapLiveness, "stackmap-liveness",
+                "StackMap Liveness Analysis", false, false)
+
+/// Default construct and initialize the pass.
+StackMapLiveness::StackMapLiveness() : MachineFunctionPass(ID) {
+  initializeStackMapLivenessPass(*PassRegistry::getPassRegistry());
+}
+
+/// Tell the pass manager which passes we depend on and what information we
+/// preserve.
+void StackMapLiveness::getAnalysisUsage(AnalysisUsage &AU) const {
+  // We preserve all information.
+  AU.setPreservesAll();
+  AU.setPreservesCFG();
+  MachineFunctionPass::getAnalysisUsage(AU);
+}
+
+/// Calculate the liveness information for the given machine function.
+bool StackMapLiveness::runOnMachineFunction(MachineFunction &MF) {
+  if (!EnablePatchPointLiveness)
+    return false;
+
+  LLVM_DEBUG(dbgs() << "********** COMPUTING STACKMAP LIVENESS: "
+                    << MF.getName() << " **********\n");
+  TRI = MF.getSubtarget().getRegisterInfo();
+  ++NumStackMapFuncVisited;
+
+  // Skip this function if there are no patchpoints to process.
+  if (!MF.getFrameInfo().hasPatchPoint()) {
+    ++NumStackMapFuncSkipped;
+    return false;
+  }
+  return calculateLiveness(MF);
+}
+
+/// Performs the actual liveness calculation for the function.
+bool StackMapLiveness::calculateLiveness(MachineFunction &MF) {
+  bool HasChanged = false;
+  // For all basic blocks in the function.
+  for (auto &MBB : MF) {
+    LLVM_DEBUG(dbgs() << "****** BB " << MBB.getName() << " ******\n");
+    LiveRegs.init(*TRI);
+    // FIXME: This should probably be addLiveOuts().
+    LiveRegs.addLiveOutsNoPristines(MBB);
+    bool HasStackMap = false;
+    // Reverse iterate over all instructions and add the current live register
+    // set to an instruction if we encounter a patchpoint instruction.
+    for (auto I = MBB.rbegin(), E = MBB.rend(); I != E; ++I) {
+      if (I->getOpcode() == TargetOpcode::PATCHPOINT) {
+        addLiveOutSetToMI(MF, *I);
+        HasChanged = true;
+        HasStackMap = true;
+        ++NumStackMaps;
+      }
+      LLVM_DEBUG(dbgs() << "   " << LiveRegs << "   " << *I);
+      LiveRegs.stepBackward(*I);
+    }
+    ++NumBBsVisited;
+    if (!HasStackMap)
+      ++NumBBsHaveNoStackmap;
+  }
+  return HasChanged;
+}
+
+/// Add the current register live set to the instruction.
+void StackMapLiveness::addLiveOutSetToMI(MachineFunction &MF,
+                                         MachineInstr &MI) {
+  uint32_t *Mask = createRegisterMask(MF);
+  MachineOperand MO = MachineOperand::CreateRegLiveOut(Mask);
+  MI.addOperand(MF, MO);
+}
+
+/// Create a register mask and initialize it with the registers from the
+/// register live set.
+uint32_t *StackMapLiveness::createRegisterMask(MachineFunction &MF) const {
+  // The mask is owned and cleaned up by the Machine Function.
+  uint32_t *Mask = MF.allocateRegMask();
+  for (auto Reg : LiveRegs)
+    Mask[Reg / 32] |= 1U << (Reg % 32);
+
+  // Give the target a chance to adjust the mask.
+  TRI->adjustStackMapLiveOutMask(Mask);
+
+  return Mask;
+}