LLVM  3.7.0
EdgeBundles.cpp
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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 
17 #include "llvm/CodeGen/Passes.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, /* analysis = */ true)
31 
32 char &llvm::EdgeBundlesID = EdgeBundles::ID;
33 
34 void EdgeBundles::getAnalysisUsage(AnalysisUsage &AU) const {
35  AU.setPreservesAll();
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, 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.
71 namespace llvm {
72 template<>
73 raw_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.
95 void EdgeBundles::view() const {
96  ViewGraph(*this, "EdgeBundles");
97 }
void grow(unsigned N)
grow - Increase capacity to hold 0 .
void compress()
compress - Compress equivalence classes by numbering them 0 .
void view() const
view - Visualize the annotated bipartite CFG with Graphviz.
Definition: EdgeBundles.cpp:95
void clear()
clear - Clear all classes so that grow() will assign a unique class to every integer.
Definition: IntEqClasses.h:51
unsigned getNumBlockIDs() const
getNumBlockIDs - Return the number of MBB ID's allocated.
Twine - A lightweight data structure for efficiently representing the concatenation of temporary valu...
Definition: Twine.h:79
unsigned getNumBundles() const
getNumBundles - Return the total number of bundles in the CFG.
Definition: EdgeBundles.h:46
#define G(x, y, z)
Definition: MD5.cpp:52
static char ID
Definition: EdgeBundles.h:38
void getAnalysisUsage(AnalysisUsage &AU) const override
getAnalysisUsage - Subclasses that override getAnalysisUsage must call this.
Represent the analysis usage information of a pass.
void ViewGraph(const GraphType &G, const Twine &Name, bool ShortNames=false, const Twine &Title="", GraphProgram::Name Program=GraphProgram::DOT)
ViewGraph - Emit a dot graph, run 'dot', run gv on the postscript file, then cleanup.
Definition: GraphWriter.h:348
void join(unsigned a, unsigned b)
join - Join the equivalence classes of a and b.
#define INITIALIZE_PASS(passName, arg, name, cfg, analysis)
Definition: PassSupport.h:56
static cl::opt< bool > ViewEdgeBundles("view-edge-bundles", cl::Hidden, cl::desc("Pop up a window to show edge bundle graphs"))
unsigned getBundle(unsigned N, bool Out) const
getBundle - Return the ingoing (Out = false) or outgoing (Out = true) bundle number for basic block N...
Definition: EdgeBundles.h:43
char & EdgeBundlesID
EdgeBundles analysis - Bundle machine CFG edges.
std::vector< MachineBasicBlock * >::const_iterator const_succ_iterator
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:38