197 lines
6.5 KiB
C++
197 lines
6.5 KiB
C++
//===- ProfileInfo.cpp - Profile Info Interface ---------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the abstract ProfileInfo interface, and the default
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// "no profile" implementation.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/Passes.h"
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#include "llvm/Analysis/ProfileInfo.h"
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#include "llvm/Pass.h"
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#include "llvm/Support/CFG.h"
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Support/Format.h"
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#include <set>
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using namespace llvm;
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// Register the ProfileInfo interface, providing a nice name to refer to.
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static RegisterAnalysisGroup<ProfileInfo> Z("Profile Information");
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char ProfileInfo::ID = 0;
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ProfileInfo::~ProfileInfo() {}
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const double ProfileInfo::MissingValue = -1;
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double ProfileInfo::getExecutionCount(const BasicBlock *BB) {
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std::map<const Function*, BlockCounts>::iterator J =
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BlockInformation.find(BB->getParent());
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if (J != BlockInformation.end()) {
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BlockCounts::iterator I = J->second.find(BB);
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if (I != J->second.end())
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return I->second;
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}
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pred_const_iterator PI = pred_begin(BB), PE = pred_end(BB);
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// Are there zero predecessors of this block?
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if (PI == PE) {
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// If this is the entry block, look for the Null -> Entry edge.
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if (BB == &BB->getParent()->getEntryBlock())
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return getEdgeWeight(getEdge(0, BB));
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else
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return 0; // Otherwise, this is a dead block.
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}
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// Otherwise, if there are predecessors, the execution count of this block is
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// the sum of the edge frequencies from the incoming edges.
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std::set<const BasicBlock*> ProcessedPreds;
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double Count = 0;
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for (; PI != PE; ++PI)
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if (ProcessedPreds.insert(*PI).second) {
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double w = getEdgeWeight(getEdge(*PI, BB));
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if (w == MissingValue) {
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Count = MissingValue;
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break;
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}
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Count += w;
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}
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if (Count != MissingValue) BlockInformation[BB->getParent()][BB] = Count;
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return Count;
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}
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double ProfileInfo::getExecutionCount(const Function *F) {
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std::map<const Function*, double>::iterator J =
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FunctionInformation.find(F);
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if (J != FunctionInformation.end())
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return J->second;
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// isDeclaration() is checked here and not at start of function to allow
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// functions without a body still to have a execution count.
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if (F->isDeclaration()) return MissingValue;
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double Count = getExecutionCount(&F->getEntryBlock());
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if (Count != MissingValue) FunctionInformation[F] = Count;
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return Count;
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}
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/// Replaces all occurences of RmBB in the ProfilingInfo with DestBB.
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/// This checks all edges of the function the blocks reside in and replaces the
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/// occurences of RmBB with DestBB.
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void ProfileInfo::replaceAllUses(const BasicBlock *RmBB,
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const BasicBlock *DestBB) {
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DEBUG(errs() << "Replacing " << RmBB->getNameStr()
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<< " with " << DestBB->getNameStr() << "\n");
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const Function *F = DestBB->getParent();
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std::map<const Function*, EdgeWeights>::iterator J =
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EdgeInformation.find(F);
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if (J == EdgeInformation.end()) return;
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for (EdgeWeights::iterator I = J->second.begin(), E = J->second.end();
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I != E; ++I) {
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Edge e = I->first;
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Edge newedge; bool foundedge = false;
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if (e.first == RmBB) {
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newedge = getEdge(DestBB, e.second);
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foundedge = true;
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}
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if (e.second == RmBB) {
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newedge = getEdge(e.first, DestBB);
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foundedge = true;
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}
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if (foundedge) {
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double w = getEdgeWeight(e);
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EdgeInformation[F][newedge] = w;
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DEBUG(errs() << "Replacing " << e << " with " << newedge << "\n");
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J->second.erase(e);
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}
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}
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}
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/// Splits an edge in the ProfileInfo and redirects flow over NewBB.
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/// Since its possible that there is more than one edge in the CFG from FristBB
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/// to SecondBB its necessary to redirect the flow proporionally.
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void ProfileInfo::splitEdge(const BasicBlock *FirstBB,
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const BasicBlock *SecondBB,
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const BasicBlock *NewBB,
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bool MergeIdenticalEdges) {
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const Function *F = FirstBB->getParent();
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std::map<const Function*, EdgeWeights>::iterator J =
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EdgeInformation.find(F);
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if (J == EdgeInformation.end()) return;
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// Generate edges and read current weight.
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Edge e = getEdge(FirstBB, SecondBB);
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Edge n1 = getEdge(FirstBB, NewBB);
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Edge n2 = getEdge(NewBB, SecondBB);
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EdgeWeights &ECs = J->second;
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double w = ECs[e];
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int succ_count = 0;
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if (!MergeIdenticalEdges) {
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// First count the edges from FristBB to SecondBB, if there is more than
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// one, only slice out a proporional part for NewBB.
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for(succ_const_iterator BBI = succ_begin(FirstBB), BBE = succ_end(FirstBB);
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BBI != BBE; ++BBI) {
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if (*BBI == SecondBB) succ_count++;
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}
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// When the NewBB is completely new, increment the count by one so that
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// the counts are properly distributed.
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if (getExecutionCount(NewBB) == ProfileInfo::MissingValue) succ_count++;
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} else {
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// When the edges are merged anyway, then redirect all flow.
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succ_count = 1;
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}
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// We know now how many edges there are from FirstBB to SecondBB, reroute a
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// proportional part of the edge weight over NewBB.
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double neww = w / succ_count;
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ECs[n1] += neww;
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ECs[n2] += neww;
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BlockInformation[F][NewBB] += neww;
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if (succ_count == 1) {
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ECs.erase(e);
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} else {
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ECs[e] -= neww;
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}
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}
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raw_ostream& llvm::operator<<(raw_ostream &O, ProfileInfo::Edge E) {
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O << "(";
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O << (E.first ? E.first->getNameStr() : "0");
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O << ",";
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O << (E.second ? E.second->getNameStr() : "0");
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return O << ")";
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}
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//===----------------------------------------------------------------------===//
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// NoProfile ProfileInfo implementation
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//
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namespace {
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struct VISIBILITY_HIDDEN NoProfileInfo
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: public ImmutablePass, public ProfileInfo {
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static char ID; // Class identification, replacement for typeinfo
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NoProfileInfo() : ImmutablePass(&ID) {}
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};
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} // End of anonymous namespace
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char NoProfileInfo::ID = 0;
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// Register this pass...
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static RegisterPass<NoProfileInfo>
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X("no-profile", "No Profile Information", false, true);
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// Declare that we implement the ProfileInfo interface
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static RegisterAnalysisGroup<ProfileInfo, true> Y(X);
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ImmutablePass *llvm::createNoProfileInfoPass() { return new NoProfileInfo(); }
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