1//===-------- EdgeBundles.cpp - Bundles of CFG edges ----------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file provides the implementation of the EdgeBundles analysis. 11// 12//===----------------------------------------------------------------------===// 13 14#include "llvm/CodeGen/EdgeBundles.h" 15#include "llvm/CodeGen/MachineBasicBlock.h" 16#include "llvm/CodeGen/MachineFunction.h" 17#include "llvm/CodeGen/Passes.h" 18#include "llvm/Support/CommandLine.h" 19#include "llvm/Support/GraphWriter.h" 20 21using namespace llvm; 22 23static cl::opt<bool> 24ViewEdgeBundles("view-edge-bundles", cl::Hidden, 25 cl::desc("Pop up a window to show edge bundle graphs")); 26 27char EdgeBundles::ID = 0; 28 29INITIALIZE_PASS(EdgeBundles, "edge-bundles", "Bundle Machine CFG Edges", 30 /* cfg = */true, /* analysis = */ true) 31 32char &llvm::EdgeBundlesID = EdgeBundles::ID; 33 34void EdgeBundles::getAnalysisUsage(AnalysisUsage &AU) const { 35 AU.setPreservesAll(); 36 MachineFunctionPass::getAnalysisUsage(AU); 37} 38 39bool EdgeBundles::runOnMachineFunction(MachineFunction &mf) { 40 MF = &mf; 41 EC.clear(); 42 EC.grow(2 * MF->getNumBlockIDs()); 43 44 for (const auto &MBB : *MF) { 45 unsigned OutE = 2 * MBB.getNumber() + 1; 46 // Join the outgoing bundle with the ingoing bundles of all successors. 47 for (MachineBasicBlock::const_succ_iterator SI = MBB.succ_begin(), 48 SE = MBB.succ_end(); SI != SE; ++SI) 49 EC.join(OutE, 2 * (*SI)->getNumber()); 50 } 51 EC.compress(); 52 if (ViewEdgeBundles) 53 view(); 54 55 // Compute the reverse mapping. 56 Blocks.clear(); 57 Blocks.resize(getNumBundles()); 58 59 for (unsigned i = 0, e = MF->getNumBlockIDs(); i != e; ++i) { 60 unsigned b0 = getBundle(i, 0); 61 unsigned b1 = getBundle(i, 1); 62 Blocks[b0].push_back(i); 63 if (b1 != b0) 64 Blocks[b1].push_back(i); 65 } 66 67 return false; 68} 69 70/// Specialize WriteGraph, the standard implementation won't work. 71namespace llvm { 72template<> 73raw_ostream &WriteGraph<>(raw_ostream &O, const EdgeBundles &G, 74 bool ShortNames, 75 const Twine &Title) { 76 const MachineFunction *MF = G.getMachineFunction(); 77 78 O << "digraph {\n"; 79 for (const auto &MBB : *MF) { 80 unsigned BB = MBB.getNumber(); 81 O << "\t\"BB#" << BB << "\" [ shape=box ]\n" 82 << '\t' << G.getBundle(BB, false) << " -> \"BB#" << BB << "\"\n" 83 << "\t\"BB#" << BB << "\" -> " << G.getBundle(BB, true) << '\n'; 84 for (MachineBasicBlock::const_succ_iterator SI = MBB.succ_begin(), 85 SE = MBB.succ_end(); SI != SE; ++SI) 86 O << "\t\"BB#" << BB << "\" -> \"BB#" << (*SI)->getNumber() 87 << "\" [ color=lightgray ]\n"; 88 } 89 O << "}\n"; 90 return O; 91} 92} 93 94/// view - Visualize the annotated bipartite CFG with Graphviz. 95void EdgeBundles::view() const { 96 ViewGraph(*this, "EdgeBundles"); 97} 98