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-rw-r--r--llvm/lib/Analysis/BlockFrequencyInfo.cpp342
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diff --git a/llvm/lib/Analysis/BlockFrequencyInfo.cpp b/llvm/lib/Analysis/BlockFrequencyInfo.cpp
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+//===- BlockFrequencyInfo.cpp - Block Frequency 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
+//
+//===----------------------------------------------------------------------===//
+//
+// Loops should be simplified before this analysis.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/BlockFrequencyInfo.h"
+#include "llvm/ADT/APInt.h"
+#include "llvm/ADT/None.h"
+#include "llvm/ADT/iterator.h"
+#include "llvm/Analysis/BlockFrequencyInfoImpl.h"
+#include "llvm/Analysis/BranchProbabilityInfo.h"
+#include "llvm/Analysis/LoopInfo.h"
+#include "llvm/IR/CFG.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/PassManager.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/GraphWriter.h"
+#include "llvm/Support/raw_ostream.h"
+#include <algorithm>
+#include <cassert>
+#include <string>
+
+using namespace llvm;
+
+#define DEBUG_TYPE "block-freq"
+
+static cl::opt<GVDAGType> ViewBlockFreqPropagationDAG(
+ "view-block-freq-propagation-dags", cl::Hidden,
+ cl::desc("Pop up a window to show a dag displaying how block "
+ "frequencies propagation through the CFG."),
+ cl::values(clEnumValN(GVDT_None, "none", "do not display graphs."),
+ clEnumValN(GVDT_Fraction, "fraction",
+ "display a graph using the "
+ "fractional block frequency representation."),
+ clEnumValN(GVDT_Integer, "integer",
+ "display a graph using the raw "
+ "integer fractional block frequency representation."),
+ clEnumValN(GVDT_Count, "count", "display a graph using the real "
+ "profile count if available.")));
+
+cl::opt<std::string>
+ ViewBlockFreqFuncName("view-bfi-func-name", cl::Hidden,
+ cl::desc("The option to specify "
+ "the name of the function "
+ "whose CFG will be displayed."));
+
+cl::opt<unsigned>
+ ViewHotFreqPercent("view-hot-freq-percent", cl::init(10), cl::Hidden,
+ cl::desc("An integer in percent used to specify "
+ "the hot blocks/edges to be displayed "
+ "in red: a block or edge whose frequency "
+ "is no less than the max frequency of the "
+ "function multiplied by this percent."));
+
+// Command line option to turn on CFG dot or text dump after profile annotation.
+cl::opt<PGOViewCountsType> PGOViewCounts(
+ "pgo-view-counts", cl::Hidden,
+ cl::desc("A boolean option to show CFG dag or text with "
+ "block profile counts and branch probabilities "
+ "right after PGO profile annotation step. The "
+ "profile counts are computed using branch "
+ "probabilities from the runtime profile data and "
+ "block frequency propagation algorithm. To view "
+ "the raw counts from the profile, use option "
+ "-pgo-view-raw-counts instead. To limit graph "
+ "display to only one function, use filtering option "
+ "-view-bfi-func-name."),
+ cl::values(clEnumValN(PGOVCT_None, "none", "do not show."),
+ clEnumValN(PGOVCT_Graph, "graph", "show a graph."),
+ clEnumValN(PGOVCT_Text, "text", "show in text.")));
+
+static cl::opt<bool> PrintBlockFreq(
+ "print-bfi", cl::init(false), cl::Hidden,
+ cl::desc("Print the block frequency info."));
+
+cl::opt<std::string> PrintBlockFreqFuncName(
+ "print-bfi-func-name", cl::Hidden,
+ cl::desc("The option to specify the name of the function "
+ "whose block frequency info is printed."));
+
+namespace llvm {
+
+static GVDAGType getGVDT() {
+ if (PGOViewCounts == PGOVCT_Graph)
+ return GVDT_Count;
+ return ViewBlockFreqPropagationDAG;
+}
+
+template <>
+struct GraphTraits<BlockFrequencyInfo *> {
+ using NodeRef = const BasicBlock *;
+ using ChildIteratorType = succ_const_iterator;
+ using nodes_iterator = pointer_iterator<Function::const_iterator>;
+
+ static NodeRef getEntryNode(const BlockFrequencyInfo *G) {
+ return &G->getFunction()->front();
+ }
+
+ static ChildIteratorType child_begin(const NodeRef N) {
+ return succ_begin(N);
+ }
+
+ static ChildIteratorType child_end(const NodeRef N) { return succ_end(N); }
+
+ static nodes_iterator nodes_begin(const BlockFrequencyInfo *G) {
+ return nodes_iterator(G->getFunction()->begin());
+ }
+
+ static nodes_iterator nodes_end(const BlockFrequencyInfo *G) {
+ return nodes_iterator(G->getFunction()->end());
+ }
+};
+
+using BFIDOTGTraitsBase =
+ BFIDOTGraphTraitsBase<BlockFrequencyInfo, BranchProbabilityInfo>;
+
+template <>
+struct DOTGraphTraits<BlockFrequencyInfo *> : public BFIDOTGTraitsBase {
+ explicit DOTGraphTraits(bool isSimple = false)
+ : BFIDOTGTraitsBase(isSimple) {}
+
+ std::string getNodeLabel(const BasicBlock *Node,
+ const BlockFrequencyInfo *Graph) {
+
+ return BFIDOTGTraitsBase::getNodeLabel(Node, Graph, getGVDT());
+ }
+
+ std::string getNodeAttributes(const BasicBlock *Node,
+ const BlockFrequencyInfo *Graph) {
+ return BFIDOTGTraitsBase::getNodeAttributes(Node, Graph,
+ ViewHotFreqPercent);
+ }
+
+ std::string getEdgeAttributes(const BasicBlock *Node, EdgeIter EI,
+ const BlockFrequencyInfo *BFI) {
+ return BFIDOTGTraitsBase::getEdgeAttributes(Node, EI, BFI, BFI->getBPI(),
+ ViewHotFreqPercent);
+ }
+};
+
+} // end namespace llvm
+
+BlockFrequencyInfo::BlockFrequencyInfo() = default;
+
+BlockFrequencyInfo::BlockFrequencyInfo(const Function &F,
+ const BranchProbabilityInfo &BPI,
+ const LoopInfo &LI) {
+ calculate(F, BPI, LI);
+}
+
+BlockFrequencyInfo::BlockFrequencyInfo(BlockFrequencyInfo &&Arg)
+ : BFI(std::move(Arg.BFI)) {}
+
+BlockFrequencyInfo &BlockFrequencyInfo::operator=(BlockFrequencyInfo &&RHS) {
+ releaseMemory();
+ BFI = std::move(RHS.BFI);
+ return *this;
+}
+
+// Explicitly define the default constructor otherwise it would be implicitly
+// defined at the first ODR-use which is the BFI member in the
+// LazyBlockFrequencyInfo header. The dtor needs the BlockFrequencyInfoImpl
+// template instantiated which is not available in the header.
+BlockFrequencyInfo::~BlockFrequencyInfo() = default;
+
+bool BlockFrequencyInfo::invalidate(Function &F, const PreservedAnalyses &PA,
+ FunctionAnalysisManager::Invalidator &) {
+ // Check whether the analysis, all analyses on functions, or the function's
+ // CFG have been preserved.
+ auto PAC = PA.getChecker<BlockFrequencyAnalysis>();
+ return !(PAC.preserved() || PAC.preservedSet<AllAnalysesOn<Function>>() ||
+ PAC.preservedSet<CFGAnalyses>());
+}
+
+void BlockFrequencyInfo::calculate(const Function &F,
+ const BranchProbabilityInfo &BPI,
+ const LoopInfo &LI) {
+ if (!BFI)
+ BFI.reset(new ImplType);
+ BFI->calculate(F, BPI, LI);
+ if (ViewBlockFreqPropagationDAG != GVDT_None &&
+ (ViewBlockFreqFuncName.empty() ||
+ F.getName().equals(ViewBlockFreqFuncName))) {
+ view();
+ }
+ if (PrintBlockFreq &&
+ (PrintBlockFreqFuncName.empty() ||
+ F.getName().equals(PrintBlockFreqFuncName))) {
+ print(dbgs());
+ }
+}
+
+BlockFrequency BlockFrequencyInfo::getBlockFreq(const BasicBlock *BB) const {
+ return BFI ? BFI->getBlockFreq(BB) : 0;
+}
+
+Optional<uint64_t>
+BlockFrequencyInfo::getBlockProfileCount(const BasicBlock *BB,
+ bool AllowSynthetic) const {
+ if (!BFI)
+ return None;
+
+ return BFI->getBlockProfileCount(*getFunction(), BB, AllowSynthetic);
+}
+
+Optional<uint64_t>
+BlockFrequencyInfo::getProfileCountFromFreq(uint64_t Freq) const {
+ if (!BFI)
+ return None;
+ return BFI->getProfileCountFromFreq(*getFunction(), Freq);
+}
+
+bool BlockFrequencyInfo::isIrrLoopHeader(const BasicBlock *BB) {
+ assert(BFI && "Expected analysis to be available");
+ return BFI->isIrrLoopHeader(BB);
+}
+
+void BlockFrequencyInfo::setBlockFreq(const BasicBlock *BB, uint64_t Freq) {
+ assert(BFI && "Expected analysis to be available");
+ BFI->setBlockFreq(BB, Freq);
+}
+
+void BlockFrequencyInfo::setBlockFreqAndScale(
+ const BasicBlock *ReferenceBB, uint64_t Freq,
+ SmallPtrSetImpl<BasicBlock *> &BlocksToScale) {
+ assert(BFI && "Expected analysis to be available");
+ // Use 128 bits APInt to avoid overflow.
+ APInt NewFreq(128, Freq);
+ APInt OldFreq(128, BFI->getBlockFreq(ReferenceBB).getFrequency());
+ APInt BBFreq(128, 0);
+ for (auto *BB : BlocksToScale) {
+ BBFreq = BFI->getBlockFreq(BB).getFrequency();
+ // Multiply first by NewFreq and then divide by OldFreq
+ // to minimize loss of precision.
+ BBFreq *= NewFreq;
+ // udiv is an expensive operation in the general case. If this ends up being
+ // a hot spot, one of the options proposed in
+ // https://reviews.llvm.org/D28535#650071 could be used to avoid this.
+ BBFreq = BBFreq.udiv(OldFreq);
+ BFI->setBlockFreq(BB, BBFreq.getLimitedValue());
+ }
+ BFI->setBlockFreq(ReferenceBB, Freq);
+}
+
+/// Pop up a ghostview window with the current block frequency propagation
+/// rendered using dot.
+void BlockFrequencyInfo::view(StringRef title) const {
+ ViewGraph(const_cast<BlockFrequencyInfo *>(this), title);
+}
+
+const Function *BlockFrequencyInfo::getFunction() const {
+ return BFI ? BFI->getFunction() : nullptr;
+}
+
+const BranchProbabilityInfo *BlockFrequencyInfo::getBPI() const {
+ return BFI ? &BFI->getBPI() : nullptr;
+}
+
+raw_ostream &BlockFrequencyInfo::
+printBlockFreq(raw_ostream &OS, const BlockFrequency Freq) const {
+ return BFI ? BFI->printBlockFreq(OS, Freq) : OS;
+}
+
+raw_ostream &
+BlockFrequencyInfo::printBlockFreq(raw_ostream &OS,
+ const BasicBlock *BB) const {
+ return BFI ? BFI->printBlockFreq(OS, BB) : OS;
+}
+
+uint64_t BlockFrequencyInfo::getEntryFreq() const {
+ return BFI ? BFI->getEntryFreq() : 0;
+}
+
+void BlockFrequencyInfo::releaseMemory() { BFI.reset(); }
+
+void BlockFrequencyInfo::print(raw_ostream &OS) const {
+ if (BFI)
+ BFI->print(OS);
+}
+
+INITIALIZE_PASS_BEGIN(BlockFrequencyInfoWrapperPass, "block-freq",
+ "Block Frequency Analysis", true, true)
+INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfoWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
+INITIALIZE_PASS_END(BlockFrequencyInfoWrapperPass, "block-freq",
+ "Block Frequency Analysis", true, true)
+
+char BlockFrequencyInfoWrapperPass::ID = 0;
+
+BlockFrequencyInfoWrapperPass::BlockFrequencyInfoWrapperPass()
+ : FunctionPass(ID) {
+ initializeBlockFrequencyInfoWrapperPassPass(*PassRegistry::getPassRegistry());
+}
+
+BlockFrequencyInfoWrapperPass::~BlockFrequencyInfoWrapperPass() = default;
+
+void BlockFrequencyInfoWrapperPass::print(raw_ostream &OS,
+ const Module *) const {
+ BFI.print(OS);
+}
+
+void BlockFrequencyInfoWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.addRequired<BranchProbabilityInfoWrapperPass>();
+ AU.addRequired<LoopInfoWrapperPass>();
+ AU.setPreservesAll();
+}
+
+void BlockFrequencyInfoWrapperPass::releaseMemory() { BFI.releaseMemory(); }
+
+bool BlockFrequencyInfoWrapperPass::runOnFunction(Function &F) {
+ BranchProbabilityInfo &BPI =
+ getAnalysis<BranchProbabilityInfoWrapperPass>().getBPI();
+ LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
+ BFI.calculate(F, BPI, LI);
+ return false;
+}
+
+AnalysisKey BlockFrequencyAnalysis::Key;
+BlockFrequencyInfo BlockFrequencyAnalysis::run(Function &F,
+ FunctionAnalysisManager &AM) {
+ BlockFrequencyInfo BFI;
+ BFI.calculate(F, AM.getResult<BranchProbabilityAnalysis>(F),
+ AM.getResult<LoopAnalysis>(F));
+ return BFI;
+}
+
+PreservedAnalyses
+BlockFrequencyPrinterPass::run(Function &F, FunctionAnalysisManager &AM) {
+ OS << "Printing analysis results of BFI for function "
+ << "'" << F.getName() << "':"
+ << "\n";
+ AM.getResult<BlockFrequencyAnalysis>(F).print(OS);
+ return PreservedAnalyses::all();
+}
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-16 23:37:53 +0000