1 //===-------- EdgeBundles.cpp - Bundles of CFG edges ----------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file provides the implementation of the EdgeBundles analysis. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "llvm/CodeGen/EdgeBundles.h" 14 #include "llvm/CodeGen/MachineBasicBlock.h" 15 #include "llvm/CodeGen/MachineFunction.h" 16 #include "llvm/CodeGen/Passes.h" 17 #include "llvm/Support/CommandLine.h" 18 #include "llvm/Support/GraphWriter.h" 19 #include "llvm/Support/raw_ostream.h" 20 21 using namespace llvm; 22 23 static cl::opt<bool> 24 ViewEdgeBundles("view-edge-bundles", cl::Hidden, 25 cl::desc("Pop up a window to show edge bundle graphs")); 26 27 char EdgeBundles::ID = 0; 28 29 INITIALIZE_PASS(EdgeBundles, "edge-bundles", "Bundle Machine CFG Edges", 30 /* cfg = */true, /* is_analysis = */ true) 31 32 char &llvm::EdgeBundlesID = EdgeBundles::ID; 33 34 void EdgeBundles::getAnalysisUsage(AnalysisUsage &AU) const { 35 AU.setPreservesAll(); 36 MachineFunctionPass::getAnalysisUsage(AU); 37 } 38 39 bool 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, false); 61 unsigned b1 = getBundle(i, true); 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. 71 namespace llvm { 72 73 template<> 74 raw_ostream &WriteGraph<>(raw_ostream &O, const EdgeBundles &G, 75 bool ShortNames, 76 const Twine &Title) { 77 const MachineFunction *MF = G.getMachineFunction(); 78 79 O << "digraph {\n"; 80 for (const auto &MBB : *MF) { 81 unsigned BB = MBB.getNumber(); 82 O << "\t\"" << printMBBReference(MBB) << "\" [ shape=box ]\n" 83 << '\t' << G.getBundle(BB, false) << " -> \"" << printMBBReference(MBB) 84 << "\"\n" 85 << "\t\"" << printMBBReference(MBB) << "\" -> " << G.getBundle(BB, true) 86 << '\n'; 87 for (MachineBasicBlock::const_succ_iterator SI = MBB.succ_begin(), 88 SE = MBB.succ_end(); SI != SE; ++SI) 89 O << "\t\"" << printMBBReference(MBB) << "\" -> \"" 90 << printMBBReference(**SI) << "\" [ color=lightgray ]\n"; 91 } 92 O << "}\n"; 93 return O; 94 } 95 96 } // end namespace llvm 97 98 /// view - Visualize the annotated bipartite CFG with Graphviz. 99 void EdgeBundles::view() const { 100 ViewGraph(*this, "EdgeBundles"); 101 } 102