[NFC] Move DroppedVariableStats to its own file

llvm/include/llvm/Passes/DroppedVariableStats.h

@@ -14,11 +14,9 @@
 #ifndef LLVM_CODEGEN_DROPPEDVARIABLESTATS_H
 #define LLVM_CODEGEN_DROPPEDVARIABLESTATS_H
 
-#include "llvm/CodeGen/MachinePassManager.h"
 #include "llvm/IR/DebugInfoMetadata.h"
 #include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/IR/Function.h"
-#include "llvm/IR/Module.h"
 #include "llvm/IR/PassInstrumentation.h"
 
 namespace llvm {
@@ -92,24 +90,75 @@ class DroppedVariableStats {
   void calculateDroppedStatsAndPrint(DebugVariables &DbgVariables,
                                      StringRef FuncName, StringRef PassID,
                                      StringRef FuncOrModName,
-                                     StringRef PassLevel, const Function *Func);
+                                     StringRef PassLevel,
+                                     const Function *Func) {
+    unsigned DroppedCount = 0;
+    DenseSet<VarID> &DebugVariablesBeforeSet =
+        DbgVariables.DebugVariablesBefore;
+    DenseSet<VarID> &DebugVariablesAfterSet = DbgVariables.DebugVariablesAfter;
+    DenseMap<VarID, DILocation *> &InlinedAtsMap = InlinedAts.back()[FuncName];
+    // Find an Instruction that shares the same scope as the dropped #dbg_value
+    // or has a scope that is the child of the scope of the #dbg_value, and has
+    // an inlinedAt equal to the inlinedAt of the #dbg_value or it's inlinedAt
+    // chain contains the inlinedAt of the #dbg_value, if such an Instruction is
+    // found, debug information is dropped.
+    for (VarID Var : DebugVariablesBeforeSet) {
+      if (DebugVariablesAfterSet.contains(Var))
+        continue;
+      visitEveryInstruction(DroppedCount, InlinedAtsMap, Var);
+      removeVarFromAllSets(Var, Func);
+    }
+    if (DroppedCount > 0) {
+      llvm::outs() << PassLevel << ", " << PassID << ", " << DroppedCount
+                   << ", " << FuncOrModName << "\n";
+      PassDroppedVariables = true;
+    } else
+      PassDroppedVariables = false;
+  }
 
   /// Check if a \p Var has been dropped or is a false positive. Also update the
   /// \p DroppedCount if a debug variable is dropped.
   bool updateDroppedCount(DILocation *DbgLoc, const DIScope *Scope,
                           const DIScope *DbgValScope,
                           DenseMap<VarID, DILocation *> &InlinedAtsMap,
-                          VarID Var, unsigned &DroppedCount);
+                          VarID Var, unsigned &DroppedCount) {
+    // If the Scope is a child of, or equal to the DbgValScope and is inlined at
+    // the Var's InlinedAt location, return true to signify that the Var has
+    // been dropped.
+    if (isScopeChildOfOrEqualTo(Scope, DbgValScope))
+      if (isInlinedAtChildOfOrEqualTo(DbgLoc->getInlinedAt(),
+                                      InlinedAtsMap[Var])) {
+        // Found another instruction in the variable's scope, so there exists a
+        // break point at which the variable could be observed. Count it as
+        // dropped.
+        DroppedCount++;
+        return true;
+      }
+    return false;
+  }
   /// Run code to populate relevant data structures over an llvm::Function or
   /// llvm::MachineFunction.
-  void run(DebugVariables &DbgVariables, StringRef FuncName, bool Before);
+  void run(DebugVariables &DbgVariables, StringRef FuncName, bool Before) {
+    auto &VarIDSet = (Before ? DbgVariables.DebugVariablesBefore
+                             : DbgVariables.DebugVariablesAfter);
+    auto &InlinedAtsMap = InlinedAts.back();
+    if (Before)
+      InlinedAtsMap.try_emplace(FuncName, DenseMap<VarID, DILocation *>());
+    VarIDSet = DenseSet<VarID>();
+    visitEveryDebugRecord(VarIDSet, InlinedAtsMap, FuncName, Before);
+  }
   /// Populate the VarIDSet and InlinedAtMap with the relevant information
   /// needed for before and after pass analysis to determine dropped variable
   /// status.
   void populateVarIDSetAndInlinedMap(
       const DILocalVariable *DbgVar, DebugLoc DbgLoc, DenseSet<VarID> &VarIDSet,
       DenseMap<StringRef, DenseMap<VarID, DILocation *>> &InlinedAtsMap,
-      StringRef FuncName, bool Before);
+      StringRef FuncName, bool Before) {
+    VarID Key{DbgVar->getScope(), DbgLoc->getInlinedAtScope(), DbgVar};
+    VarIDSet.insert(Key);
+    if (Before)
+      InlinedAtsMap[FuncName].try_emplace(Key, DbgLoc.getInlinedAt());
+  }
   /// Visit every llvm::Instruction or llvm::MachineInstruction and check if the
   /// debug variable denoted by its ID \p Var may have been dropped by an
   /// optimization pass.
@@ -136,87 +185,39 @@ class DroppedVariableStats {
   /// Return true if \p Scope is the same as \p DbgValScope or a child scope of
   /// \p DbgValScope, return false otherwise.
   bool isScopeChildOfOrEqualTo(const DIScope *Scope,
-                               const DIScope *DbgValScope);
+                               const DIScope *DbgValScope) {
+    while (Scope != nullptr) {
+      if (VisitedScope.find(Scope) == VisitedScope.end()) {
+        VisitedScope.insert(Scope);
+        if (Scope == DbgValScope) {
+          VisitedScope.clear();
+          return true;
+        }
+        Scope = Scope->getScope();
+      } else {
+        VisitedScope.clear();
+        return false;
+      }
+    }
+    return false;
+  }
   /// Return true if \p InlinedAt is the same as \p DbgValInlinedAt or part of
   /// the InlinedAt chain, return false otherwise.
   bool isInlinedAtChildOfOrEqualTo(const DILocation *InlinedAt,
-                                   const DILocation *DbgValInlinedAt);
-  bool PassDroppedVariables = false;
-};
-
-/// A class to collect and print dropped debug information due to LLVM IR
-/// optimization passes. After every LLVM IR pass is run, it will print how many
-/// #dbg_values were dropped due to that pass.
-class DroppedVariableStatsIR : public DroppedVariableStats {
-public:
-  DroppedVariableStatsIR(bool DroppedVarStatsEnabled)
-      : llvm::DroppedVariableStats(DroppedVarStatsEnabled) {}
-
-  void runBeforePass(Any IR) {
-    setup();
-    if (const auto *M = unwrapIR<Module>(IR))
-      return this->runOnModule(M, true);
-    if (const auto *F = unwrapIR<Function>(IR))
-      return this->runOnFunction(F, true);
-  }
-
-  void runAfterPass(StringRef P, Any IR) {
-    if (const auto *M = unwrapIR<Module>(IR))
-      runAfterPassModule(P, M);
-    else if (const auto *F = unwrapIR<Function>(IR))
-      runAfterPassFunction(P, F);
-    cleanup();
-  }
-
-  void registerCallbacks(PassInstrumentationCallbacks &PIC);
-
-private:
-  const Function *Func;
-
-  void runAfterPassFunction(StringRef PassID, const Function *F) {
-    runOnFunction(F, false);
-    calculateDroppedVarStatsOnFunction(F, PassID, F->getName().str(),
-                                       "Function");
-  }
-
-  void runAfterPassModule(StringRef PassID, const Module *M) {
-    runOnModule(M, false);
-    calculateDroppedVarStatsOnModule(M, PassID, M->getName().str(), "Module");
-  }
-  /// Populate DebugVariablesBefore, DebugVariablesAfter, InlinedAts before or
-  /// after a pass has run to facilitate dropped variable calculation for an
-  /// llvm::Function.
-  void runOnFunction(const Function *F, bool Before);
-  /// Iterate over all Instructions in a Function and report any dropped debug
-  /// information.
-  void calculateDroppedVarStatsOnFunction(const Function *F, StringRef PassID,
-                                          StringRef FuncOrModName,
-                                          StringRef PassLevel);
-  /// Populate DebugVariablesBefore, DebugVariablesAfter, InlinedAts before or
-  /// after a pass has run to facilitate dropped variable calculation for an
-  /// llvm::Module. Calls runOnFunction on every Function in the Module.
-  void runOnModule(const Module *M, bool Before);
-  /// Iterate over all Functions in a Module and report any dropped debug
-  /// information. Will call calculateDroppedVarStatsOnFunction on every
-  /// Function.
-  void calculateDroppedVarStatsOnModule(const Module *M, StringRef PassID,
-                                        StringRef FuncOrModName,
-                                        StringRef PassLevel);
-  /// Override base class method to run on an llvm::Function specifically.
-  virtual void
-  visitEveryInstruction(unsigned &DroppedCount,
-                        DenseMap<VarID, DILocation *> &InlinedAtsMap,
-                        VarID Var) override;
-  /// Override base class method to run on #dbg_values specifically.
-  virtual void visitEveryDebugRecord(
-      DenseSet<VarID> &VarIDSet,
-      DenseMap<StringRef, DenseMap<VarID, DILocation *>> &InlinedAtsMap,
-      StringRef FuncName, bool Before) override;
-
-  template <typename IRUnitT> static const IRUnitT *unwrapIR(Any IR) {
-    const IRUnitT **IRPtr = llvm::any_cast<const IRUnitT *>(&IR);
-    return IRPtr ? *IRPtr : nullptr;
+                                   const DILocation *DbgValInlinedAt) {
+    if (DbgValInlinedAt == InlinedAt)
+      return true;
+    if (!DbgValInlinedAt)
+      return false;
+    auto *IA = InlinedAt;
+    while (IA) {
+      if (IA == DbgValInlinedAt)
+        return true;
+      IA = IA->getInlinedAt();
+    }
+    return false;
   }
+  bool PassDroppedVariables = false;
 };
 
 } // namespace llvm

llvm/include/llvm/Passes/DroppedVariableStatsIR.h

@@ -0,0 +1,101 @@
+///===- DroppedVariableStatsIR.h - Opt Diagnostics -*- C++ -*--------------===//
+///
+/// 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
+///
+///===---------------------------------------------------------------------===//
+/// \file
+/// Dropped Variable Statistics for Debug Information. Reports any number
+/// of #dbg_value that get dropped due to an optimization pass.
+///
+///===---------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_DROPPEDVARIABLESTATSIR_H
+#define LLVM_CODEGEN_DROPPEDVARIABLESTATSIR_H
+
+#include "llvm/IR/InstIterator.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Passes/DroppedVariableStats.h"
+
+namespace llvm {
+
+/// A class to collect and print dropped debug information due to LLVM IR
+/// optimization passes. After every LLVM IR pass is run, it will print how many
+/// #dbg_values were dropped due to that pass.
+class DroppedVariableStatsIR : public DroppedVariableStats {
+public:
+  DroppedVariableStatsIR(bool DroppedVarStatsEnabled)
+      : llvm::DroppedVariableStats(DroppedVarStatsEnabled) {}
+
+  void runBeforePass(Any IR) {
+    setup();
+    if (const auto *M = unwrapIR<Module>(IR))
+      return this->runOnModule(M, true);
+    if (const auto *F = unwrapIR<Function>(IR))
+      return this->runOnFunction(F, true);
+  }
+
+  void runAfterPass(StringRef P, Any IR) {
+    if (const auto *M = unwrapIR<Module>(IR))
+      runAfterPassModule(P, M);
+    else if (const auto *F = unwrapIR<Function>(IR))
+      runAfterPassFunction(P, F);
+    cleanup();
+  }
+
+  void registerCallbacks(PassInstrumentationCallbacks &PIC);
+
+private:
+  const Function *Func;
+
+  void runAfterPassFunction(StringRef PassID, const Function *F) {
+    runOnFunction(F, false);
+    calculateDroppedVarStatsOnFunction(F, PassID, F->getName().str(),
+                                       "Function");
+  }
+
+  void runAfterPassModule(StringRef PassID, const Module *M) {
+    runOnModule(M, false);
+    calculateDroppedVarStatsOnModule(M, PassID, M->getName().str(), "Module");
+  }
+  /// Populate DebugVariablesBefore, DebugVariablesAfter, InlinedAts before or
+  /// after a pass has run to facilitate dropped variable calculation for an
+  /// llvm::Function.
+  void runOnFunction(const Function *F, bool Before);
+  /// Iterate over all Instructions in a Function and report any dropped debug
+  /// information.
+  void calculateDroppedVarStatsOnFunction(const Function *F, StringRef PassID,
+                                          StringRef FuncOrModName,
+                                          StringRef PassLevel);
+  /// Populate DebugVariablesBefore, DebugVariablesAfter, InlinedAts before or
+  /// after a pass has run to facilitate dropped variable calculation for an
+  /// llvm::Module. Calls runOnFunction on every Function in the Module.
+  void runOnModule(const Module *M, bool Before);
+  /// Iterate over all Functions in a Module and report any dropped debug
+  /// information. Will call calculateDroppedVarStatsOnFunction on every
+  /// Function.
+  void calculateDroppedVarStatsOnModule(const Module *M, StringRef PassID,
+                                        StringRef FuncOrModName,
+                                        StringRef PassLevel);
+  /// Override base class method to run on an llvm::Function specifically.
+  virtual void
+  visitEveryInstruction(unsigned &DroppedCount,
+                        DenseMap<VarID, DILocation *> &InlinedAtsMap,
+                        VarID Var) override;
+
+  /// Override base class method to run on #dbg_values specifically.
+  virtual void visitEveryDebugRecord(
+      DenseSet<VarID> &VarIDSet,
+      DenseMap<StringRef, DenseMap<VarID, DILocation *>> &InlinedAtsMap,
+      StringRef FuncName, bool Before) override;
+
+  template <typename IRUnitT> static const IRUnitT *unwrapIR(Any IR) {
+    const IRUnitT **IRPtr = llvm::any_cast<const IRUnitT *>(&IR);
+    return IRPtr ? *IRPtr : nullptr;
+  }
+};
+
+} // namespace llvm
+
+#endif

llvm/include/llvm/Passes/StandardInstrumentations.h

@@ -25,7 +25,7 @@
 #include "llvm/IR/OptBisect.h"
 #include "llvm/IR/PassTimingInfo.h"
 #include "llvm/IR/ValueHandle.h"
-#include "llvm/Passes/DroppedVariableStats.h"
+#include "llvm/Passes/DroppedVariableStatsIR.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/TimeProfiler.h"
 #include "llvm/Transforms/IPO/SampleProfileProbe.h"

llvm/lib/Passes/CMakeLists.txt

@@ -1,6 +1,6 @@
 add_llvm_component_library(LLVMPasses
   CodeGenPassBuilder.cpp
-  DroppedVariableStats.cpp
+  DroppedVariableStatsIR.cpp
   OptimizationLevel.cpp
   PassBuilder.cpp
   PassBuilderBindings.cpp