EdgeBundles.cpp revision 8dd070edc2209ecfdae49780ec1596b349e2cbd1 
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/GraphWriter.h"
19
20using namespace llvm;
21
22char EdgeBundles::ID = 0;
23
24INITIALIZE_PASS(EdgeBundles, "edge-bundles", "Bundle Machine CFG Edges",
25                /* cfg = */true, /* analysis = */ true)
26
27char &llvm::EdgeBundlesID = EdgeBundles::ID;
28
29void EdgeBundles::getAnalysisUsage(AnalysisUsage &AU) const {
30  AU.setPreservesAll();
31  MachineFunctionPass::getAnalysisUsage(AU);
32}
33
34bool EdgeBundles::runOnMachineFunction(MachineFunction &mf) {
35  MF = &mf;
36  EC.clear();
37  EC.grow(2 * MF->size());
38
39  for (MachineFunction::const_iterator I = MF->begin(), E = MF->end(); I != E;
40       ++I) {
41    const MachineBasicBlock &MBB = *I;
42    unsigned OutE = 2 * MBB.getNumber() + 1;
43    // Join the outgoing bundle with the ingoing bundles of all successors.
44    for (MachineBasicBlock::const_succ_iterator SI = MBB.succ_begin(),
45           SE = MBB.succ_end(); SI != SE; ++SI)
46      EC.join(OutE, 2 * (*SI)->getNumber());
47  }
48  EC.compress();
49  return false;
50}
51
52/// view - Visualize the annotated bipartite CFG with Graphviz.
53void EdgeBundles::view() const {
54  ViewGraph(*this, "EdgeBundles");
55}
56
57/// Specialize WriteGraph, the standard implementation won't work.
58raw_ostream &llvm::WriteGraph(raw_ostream &O, const EdgeBundles &G,
59                              bool ShortNames,
60                              const std::string &Title) {
61  const MachineFunction *MF = G.getMachineFunction();
62
63  O << "digraph {\n";
64  for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
65       I != E; ++I) {
66    unsigned BB = I->getNumber();
67    O << "\t\"BB#" << BB << "\" [ shape=box ]\n"
68      << '\t' << G.getBundle(BB, false) << " -> \"BB#" << BB << "\"\n"
69      << "\t\"BB#" << BB << "\" -> " << G.getBundle(BB, true) << '\n';
70    for (MachineBasicBlock::const_succ_iterator SI = I->succ_begin(),
71           SE = I->succ_end(); SI != SE; ++SI)
72      O << "\t\"BB#" << BB << "\" -> \"BB#" << (*SI)->getNumber()
73        << "\" [ color=lightgray ]\n";
74  }
75  O << "}\n";
76  return O;
77}
78
79
80