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/ADT/Twine.h" 15 #include "llvm/CodeGen/MachineBasicBlock.h" 16 #include "llvm/CodeGen/MachineFunction.h" 17 #include "llvm/CodeGen/Passes.h" 18 #include "llvm/InitializePasses.h" 19 #include "llvm/Support/CommandLine.h" 20 #include "llvm/Support/GraphWriter.h" 21 #include "llvm/Support/raw_ostream.h" 22 23 using namespace llvm; 24 25 static cl::opt<bool> 26 ViewEdgeBundles("view-edge-bundles", cl::Hidden, 27 cl::desc("Pop up a window to show edge bundle graphs")); 28 29 char EdgeBundles::ID = 0; 30 31 INITIALIZE_PASS(EdgeBundles, "edge-bundles", "Bundle Machine CFG Edges", 32 /* cfg = */true, /* is_analysis = */ true) 33 34 char &llvm::EdgeBundlesID = EdgeBundles::ID; 35 36 void EdgeBundles::getAnalysisUsage(AnalysisUsage &AU) const { 37 AU.setPreservesAll(); 38 MachineFunctionPass::getAnalysisUsage(AU); 39 } 40 41 bool EdgeBundles::runOnMachineFunction(MachineFunction &mf) { 42 MF = &mf; 43 EC.clear(); 44 EC.grow(2 * MF->getNumBlockIDs()); 45 46 for (const auto &MBB : *MF) { 47 unsigned OutE = 2 * MBB.getNumber() + 1; 48 // Join the outgoing bundle with the ingoing bundles of all successors. 49 for (const MachineBasicBlock *Succ : MBB.successors()) 50 EC.join(OutE, 2 * Succ->getNumber()); 51 } 52 EC.compress(); 53 if (ViewEdgeBundles) 54 view(); 55 56 // Compute the reverse mapping. 57 Blocks.clear(); 58 Blocks.resize(getNumBundles()); 59 60 for (unsigned i = 0, e = MF->getNumBlockIDs(); i != e; ++i) { 61 unsigned b0 = getBundle(i, false); 62 unsigned b1 = getBundle(i, true); 63 Blocks[b0].push_back(i); 64 if (b1 != b0) 65 Blocks[b1].push_back(i); 66 } 67 68 return false; 69 } 70 71 namespace llvm { 72 73 /// Specialize WriteGraph, the standard implementation won't work. 74 template<> 75 raw_ostream &WriteGraph<>(raw_ostream &O, const EdgeBundles &G, 76 bool ShortNames, 77 const Twine &Title) { 78 const MachineFunction *MF = G.getMachineFunction(); 79 80 O << "digraph {\n"; 81 for (const auto &MBB : *MF) { 82 unsigned BB = MBB.getNumber(); 83 O << "\t\"" << printMBBReference(MBB) << "\" [ shape=box ]\n" 84 << '\t' << G.getBundle(BB, false) << " -> \"" << printMBBReference(MBB) 85 << "\"\n" 86 << "\t\"" << printMBBReference(MBB) << "\" -> " << G.getBundle(BB, true) 87 << '\n'; 88 for (const MachineBasicBlock *Succ : MBB.successors()) 89 O << "\t\"" << printMBBReference(MBB) << "\" -> \"" 90 << printMBBReference(*Succ) << "\" [ 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