[llvm] Add a pass to collect dropped var stats for MIR. (PR #115566)
via llvm-commits
llvm-commits at lists.llvm.org
Fri Nov 8 15:30:33 PST 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-llvm-ir
Author: Shubham Sandeep Rastogi (rastogishubham)
<details>
<summary>Changes</summary>
This patch uses the DroppedVariableStats class to add dropped variable
statistics for MIR passes.
---
Patch is 75.74 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/115566.diff
11 Files Affected:
- (added) llvm/include/llvm/CodeGen/DroppedVariableStats.h (+199)
- (modified) llvm/include/llvm/CodeGen/MachineFunctionPass.h (+2)
- (modified) llvm/include/llvm/Passes/StandardInstrumentations.h (+2-78)
- (modified) llvm/lib/CodeGen/CMakeLists.txt (+1)
- (added) llvm/lib/CodeGen/DroppedVariableStats.cpp (+222)
- (modified) llvm/lib/CodeGen/MachineFunctionPass.cpp (+14-2)
- (modified) llvm/lib/Passes/StandardInstrumentations.cpp (+2-178)
- (modified) llvm/unittests/IR/CMakeLists.txt (+1-1)
- (renamed) llvm/unittests/IR/DroppedVariableStatsIRTest.cpp (+28-42)
- (modified) llvm/unittests/MIR/CMakeLists.txt (+1)
- (added) llvm/unittests/MIR/DroppedVariableStatsMIRTest.cpp (+1067)
``````````diff
diff --git a/llvm/include/llvm/CodeGen/DroppedVariableStats.h b/llvm/include/llvm/CodeGen/DroppedVariableStats.h
new file mode 100644
index 00000000000000..8969105dcb08c2
--- /dev/null
+++ b/llvm/include/llvm/CodeGen/DroppedVariableStats.h
@@ -0,0 +1,199 @@
+///===- DroppedVariableStats.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_values or DBG_VALUEs that get dropped due to an optimization pass.
+///
+///===---------------------------------------------------------------------===//
+
+#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 {
+
+/// A unique key that represents a #dbg_value.
+using VarID =
+ std::tuple<const DIScope *, const DIScope *, const DILocalVariable *>;
+
+/// A base class to collect and print dropped debug information variable
+/// statistics.
+class DroppedVariableStats {
+public:
+ DroppedVariableStats(bool DroppedVarStatsEnabled)
+ : DroppedVariableStatsEnabled(DroppedVarStatsEnabled) {
+ if (DroppedVarStatsEnabled)
+ llvm::outs()
+ << "Pass Level, Pass Name, Num of Dropped Variables, Func or "
+ "Module Name\n";
+ };
+ // We intend this to be unique per-compilation, thus no copies.
+ DroppedVariableStats(const DroppedVariableStats &) = delete;
+ void operator=(const DroppedVariableStats &) = delete;
+
+ void setup() {
+ DebugVariablesStack.push_back(
+ {DenseMap<const Function *, DebugVariables>()});
+ InlinedAts.push_back(
+ {DenseMap<StringRef, DenseMap<VarID, DILocation *>>()});
+ return;
+ }
+
+ void cleanup() {
+ DebugVariablesStack.pop_back();
+ InlinedAts.pop_back();
+ return;
+ }
+
+ bool getPassDroppedVariables() { return PassDroppedVariables; }
+
+protected:
+ bool PassDroppedVariables = false;
+ bool DroppedVariableStatsEnabled = false;
+
+ struct DebugVariables {
+ /// DenseSet of VarIDs before an optimization pass has run.
+ DenseSet<VarID> DebugVariablesBefore;
+ /// DenseSet of VarIDs after an optimization pass has run.
+ DenseSet<VarID> DebugVariablesAfter;
+ };
+
+ /// A stack of a DenseMap, that maps DebugVariables for every pass to an
+ /// llvm::Function. A stack is used because an optimization pass can call
+ /// other passes.
+ SmallVector<DenseMap<const Function *, DebugVariables>> DebugVariablesStack;
+
+ /// A DenseSet tracking whether a scope was visited before.
+ DenseSet<const DIScope *> VisitedScope;
+ /// A stack of DenseMaps, which map the name of an llvm::Function to a
+ /// DenseMap of VarIDs and their inlinedAt locations before an optimization
+ /// pass has run.
+ SmallVector<DenseMap<StringRef, DenseMap<VarID, DILocation *>>> InlinedAts;
+ /// Remove a dropped #dbg_value VarID from all Sets in the
+ /// DroppedVariablesBefore stack.
+ void removeVarFromAllSets(VarID Var, const Function *F) {
+ // Do not remove Var from the last element, it will be popped from the
+ // stack.
+ for (auto &DebugVariablesMap : llvm::drop_end(DebugVariablesStack))
+ DebugVariablesMap[F].DebugVariablesBefore.erase(Var);
+ }
+ /// Return true if \p Scope is the same as \p DbgValScope or a child scope of
+ /// \p DbgValScope, return false otherwise.
+ bool isScopeChildOfOrEqualTo(DIScope *Scope, const DIScope *DbgValScope);
+ /// 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);
+};
+
+/// 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);
+ return cleanup();
+ }
+
+ void registerCallbacks(PassInstrumentationCallbacks &PIC);
+
+private:
+ 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,
+ std::string FuncOrModName,
+ std::string 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,
+ std::string FuncOrModName,
+ std::string PassLevel);
+
+ template <typename IRUnitT> static const IRUnitT *unwrapIR(Any IR) {
+ const IRUnitT **IRPtr = llvm::any_cast<const IRUnitT *>(&IR);
+ return IRPtr ? *IRPtr : nullptr;
+ }
+};
+
+/// A class to collect and print dropped debug information due to MIR
+/// optimization passes. After every MIR pass is run, it will print how many
+/// #DBG_VALUEs were dropped due to that pass.
+class DroppedVariableStatsMIR : public DroppedVariableStats {
+public:
+ DroppedVariableStatsMIR() : llvm::DroppedVariableStats(false) {}
+
+ void runBeforePass(StringRef PassID, MachineFunction *MF) {
+ if (PassID == "Debug Variable Analysis")
+ return;
+ setup();
+ return runOnMachineFunction(MF, true);
+ }
+
+ void runAfterPass(StringRef PassID, MachineFunction *MF) {
+ if (PassID == "Debug Variable Analysis")
+ return;
+ runOnMachineFunction(MF, false);
+ calculateDroppedVarStatsOnMachineFunction(MF, PassID, MF->getName().str());
+ cleanup();
+ }
+
+private:
+ /// Populate DebugVariablesBefore, DebugVariablesAfter, InlinedAts before or
+ /// after a pass has run to facilitate dropped variable calculation for an
+ /// llvm::MachineFunction.
+ void runOnMachineFunction(const MachineFunction *MF, bool Before);
+ /// Iterate over all Instructions in a MachineFunction and report any dropped
+ /// debug information.
+ void calculateDroppedVarStatsOnMachineFunction(const MachineFunction *MF,
+ StringRef PassID,
+ std::string FuncOrModName);
+};
+
+} // namespace llvm
+
+#endif
diff --git a/llvm/include/llvm/CodeGen/MachineFunctionPass.h b/llvm/include/llvm/CodeGen/MachineFunctionPass.h
index caaf22c2139e31..2ab6fb203da874 100644
--- a/llvm/include/llvm/CodeGen/MachineFunctionPass.h
+++ b/llvm/include/llvm/CodeGen/MachineFunctionPass.h
@@ -18,6 +18,7 @@
#ifndef LLVM_CODEGEN_MACHINEFUNCTIONPASS_H
#define LLVM_CODEGEN_MACHINEFUNCTIONPASS_H
+#include "llvm/CodeGen/DroppedVariableStats.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/Pass.h"
@@ -73,6 +74,7 @@ class MachineFunctionPass : public FunctionPass {
const std::string &Banner) const override;
bool runOnFunction(Function &F) override;
+ DroppedVariableStatsMIR DroppedVarStatsMF;
};
} // End llvm namespace
diff --git a/llvm/include/llvm/Passes/StandardInstrumentations.h b/llvm/include/llvm/Passes/StandardInstrumentations.h
index 9301a12c740eec..12a34c099eaffe 100644
--- a/llvm/include/llvm/Passes/StandardInstrumentations.h
+++ b/llvm/include/llvm/Passes/StandardInstrumentations.h
@@ -19,6 +19,7 @@
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/StringSet.h"
+#include "llvm/CodeGen/DroppedVariableStats.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/DebugInfoMetadata.h"
@@ -579,83 +580,6 @@ class PrintCrashIRInstrumentation {
static void SignalHandler(void *);
};
-/// A class to collect and print dropped debug information variable statistics.
-/// After every LLVM IR pass is run, it will print how many #dbg_values were
-/// dropped due to that pass.
-class DroppedVariableStats {
-public:
- DroppedVariableStats(bool DroppedVarStatsEnabled) {
- if (DroppedVarStatsEnabled)
- llvm::outs()
- << "Pass Level, Pass Name, Num of Dropped Variables, Func or "
- "Module Name\n";
- };
- // We intend this to be unique per-compilation, thus no copies.
- DroppedVariableStats(const DroppedVariableStats &) = delete;
- void operator=(const DroppedVariableStats &) = delete;
-
- void registerCallbacks(PassInstrumentationCallbacks &PIC);
- void runBeforePass(StringRef PassID, Any IR);
- void runAfterPass(StringRef PassID, Any IR, const PreservedAnalyses &PA);
- void runAfterPassInvalidated(StringRef PassID, const PreservedAnalyses &PA);
- bool getPassDroppedVariables() { return PassDroppedVariables; }
-
-private:
- bool PassDroppedVariables = false;
- /// A unique key that represents a #dbg_value.
- using VarID =
- std::tuple<const DIScope *, const DIScope *, const DILocalVariable *>;
-
- struct DebugVariables {
- /// DenseSet of VarIDs before an optimization pass has run.
- DenseSet<VarID> DebugVariablesBefore;
- /// DenseSet of VarIDs after an optimization pass has run.
- DenseSet<VarID> DebugVariablesAfter;
- };
-
- /// A stack of a DenseMap, that maps DebugVariables for every pass to an
- /// llvm::Function. A stack is used because an optimization pass can call
- /// other passes.
- SmallVector<DenseMap<const Function *, DebugVariables>> DebugVariablesStack;
-
- /// A DenseSet tracking whether a scope was visited before.
- DenseSet<const DIScope *> VisitedScope;
- /// A stack of DenseMaps, which map the name of an llvm::Function to a
- /// DenseMap of VarIDs and their inlinedAt locations before an optimization
- /// pass has run.
- SmallVector<DenseMap<StringRef, DenseMap<VarID, DILocation *>>> InlinedAts;
-
- /// 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,
- std::string FuncOrModName,
- std::string PassLevel);
- /// Iterate over all Instructions in a Function and report any dropped debug
- /// information.
- void calculateDroppedVarStatsOnFunction(const Function *F, StringRef PassID,
- std::string FuncOrModName,
- std::string PassLevel);
- /// 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);
- /// 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);
- /// Remove a dropped #dbg_value VarID from all Sets in the
- /// DroppedVariablesBefore stack.
- void removeVarFromAllSets(VarID Var, const Function *F);
- /// Return true if \p Scope is the same as \p DbgValScope or a child scope of
- /// \p DbgValScope, return false otherwise.
- bool isScopeChildOfOrEqualTo(DIScope *Scope, const DIScope *DbgValScope);
- /// 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);
-};
-
/// This class provides an interface to register all the standard pass
/// instrumentations and manages their state (if any).
class StandardInstrumentations {
@@ -673,7 +597,7 @@ class StandardInstrumentations {
PrintCrashIRInstrumentation PrintCrashIR;
IRChangedTester ChangeTester;
VerifyInstrumentation Verify;
- DroppedVariableStats DroppedStats;
+ DroppedVariableStatsIR DroppedStatsIR;
bool VerifyEach;
diff --git a/llvm/lib/CodeGen/CMakeLists.txt b/llvm/lib/CodeGen/CMakeLists.txt
index 5a17944db0ae03..3eebeaaf04b3a2 100644
--- a/llvm/lib/CodeGen/CMakeLists.txt
+++ b/llvm/lib/CodeGen/CMakeLists.txt
@@ -50,6 +50,7 @@ add_llvm_component_library(LLVMCodeGen
DeadMachineInstructionElim.cpp
DetectDeadLanes.cpp
DFAPacketizer.cpp
+ DroppedVariableStats.cpp
DwarfEHPrepare.cpp
EarlyIfConversion.cpp
EdgeBundles.cpp
diff --git a/llvm/lib/CodeGen/DroppedVariableStats.cpp b/llvm/lib/CodeGen/DroppedVariableStats.cpp
new file mode 100644
index 00000000000000..b8130784d28874
--- /dev/null
+++ b/llvm/lib/CodeGen/DroppedVariableStats.cpp
@@ -0,0 +1,222 @@
+///===- DroppedVariableStats.cpp - Opt Diagnostic -*- 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_values or DBG_VALUEs that get dropped due to an optimization pass.
+///
+///===---------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/DroppedVariableStats.h"
+#include "llvm/IR/DebugInfoMetadata.h"
+#include "llvm/IR/InstIterator.h"
+#include "llvm/IR/Module.h"
+
+using namespace llvm;
+
+bool DroppedVariableStats::isScopeChildOfOrEqualTo(DIScope *Scope,
+ 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;
+}
+
+bool DroppedVariableStats::isInlinedAtChildOfOrEqualTo(
+ const DILocation *InlinedAt, const DILocation *DbgValInlinedAt) {
+ if (DbgValInlinedAt == InlinedAt)
+ return true;
+ if (!DbgValInlinedAt)
+ return false;
+ if (!InlinedAt)
+ return false;
+ auto *IA = InlinedAt;
+ while (IA) {
+ if (IA == DbgValInlinedAt)
+ return true;
+ IA = IA->getInlinedAt();
+ }
+ return false;
+}
+
+void DroppedVariableStatsIR::runOnFunction(const Function *F, bool Before) {
+ auto &DebugVariables = DebugVariablesStack.back()[F];
+ auto &VarIDSet = (Before ? DebugVariables.DebugVariablesBefore
+ : DebugVariables.DebugVariablesAfter);
+ auto &InlinedAtsMap = InlinedAts.back();
+ auto FuncName = F->getName();
+ if (Before)
+ InlinedAtsMap.try_emplace(FuncName, DenseMap<VarID, DILocation *>());
+ VarIDSet = DenseSet<VarID>();
+ for (const auto &I : instructions(F)) {
+ for (DbgRecord &DR : I.getDbgRecordRange()) {
+ if (auto *Dbg = dyn_cast<DbgVariableRecord>(&DR)) {
+ auto *DbgVar = Dbg->getVariable();
+ auto DbgLoc = DR.getDebugLoc();
+ VarID Key{DbgVar->getScope(), DbgLoc->getInlinedAtScope(), DbgVar};
+ VarIDSet.insert(Key);
+ if (Before)
+ InlinedAtsMap[FuncName].try_emplace(Key, DbgLoc.getInlinedAt());
+ }
+ }
+ }
+}
+
+void DroppedVariableStatsIR::calculateDroppedVarStatsOnFunction(
+ const Function *F, StringRef PassID, std::string FuncOrModName,
+ std::string PassLevel) {
+ unsigned DroppedCount = 0;
+ StringRef FuncName = F->getName();
+ DebugVariables &DbgVariables = DebugVariablesStack.back()[F];
+ 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;
+ const DIScope *DbgValScope = std::get<0>(Var);
+ for (const auto &I : instructions(F)) {
+ auto *DbgLoc = I.getDebugLoc().get();
+ if (!DbgLoc)
+ continue;
+
+ auto *Scope = DbgLoc->getScope();
+ 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++;
+ break;
+ }
+ }
+ }
+ removeVarFromAllSets(Var, F);
+ }
+ if (DroppedCount > 0) {
+ llvm::outs() << PassLevel << ", " << PassID << ", " << DroppedCount << ", "
+ << FuncOrModName << "\n";
+ PassDroppedVariables = true;
+ } else
+ PassDroppedVariables = false;
+}
+
+void DroppedVariableStatsIR::runOnModule(const Module *M, bool Before) {
+ for (auto &F : *M)
+ runOnFunction(&F, Before);
+}
+
+void DroppedVariableStatsIR::calculateDroppedVarStatsOnModule(
+ const Module *M, StringRef PassID, std::string FuncOrModName,
+ std::string PassLevel) {
+ for (auto &F : *M) {
+ calculateDroppedVarStatsOnFunction(&F, PassID, FuncOrModName, PassLevel);
+ }
+}
+
+void DroppedVariableStatsIR::registerCallbacks(
+ PassInstrumentationCallbacks &PIC) {
+ if (!DroppedVariableStatsEnabled)
+ return;
+
+ PIC.registerBeforeNonSkippedPassCallback(
+ [this](StringRef P, Any IR) { return runBeforePass(IR); });
+ PIC.registerAfterPassCallback(
+ [this](StringRef P, Any IR, const PreservedAnalyses &PA) {
+ return runAfterPass(P, IR);
+ });
+ PIC.registerAfterPassInvalidatedCallback(
+ [this](StringRef P, const PreservedAnalyses &PA) { return cleanup(); });
+}
+
+void DroppedVariableStatsMIR::runOnMachineFunction(const MachineFunction *MF,
+ boo...
[truncated]
``````````
</details>
https://github.com/llvm/llvm-project/pull/115566
More information about the llvm-commits
mailing list