1 //===- GraphPrinter.cpp - Create a DOT output describing the Scop. --------===//
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 // Create a DOT output describing the Scop.
10 //
11 // For each function a dot file is created that shows the control flow graph of
12 // the function and highlights the detected Scops.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #include "polly/LinkAllPasses.h"
17 #include "polly/ScopDetection.h"
18 #include "polly/Support/ScopLocation.h"
19 #include "llvm/Analysis/DOTGraphTraitsPass.h"
20 #include "llvm/Analysis/RegionInfo.h"
21 #include "llvm/Analysis/RegionIterator.h"
22 #include "llvm/Support/CommandLine.h"
23 
24 using namespace polly;
25 using namespace llvm;
26 static cl::opt<std::string>
27     ViewFilter("polly-view-only",
28                cl::desc("Only view functions that match this pattern"),
29                cl::Hidden, cl::init(""), cl::ZeroOrMore);
30 
31 static cl::opt<bool> ViewAll("polly-view-all",
32                              cl::desc("Also show functions without any scops"),
33                              cl::Hidden, cl::init(false), cl::ZeroOrMore);
34 
35 namespace llvm {
36 template <>
37 struct GraphTraits<ScopDetection *> : public GraphTraits<RegionInfo *> {
38   static NodeRef getEntryNode(ScopDetection *SD) {
39     return GraphTraits<RegionInfo *>::getEntryNode(SD->getRI());
40   }
41   static nodes_iterator nodes_begin(ScopDetection *SD) {
42     return nodes_iterator::begin(getEntryNode(SD));
43   }
44   static nodes_iterator nodes_end(ScopDetection *SD) {
45     return nodes_iterator::end(getEntryNode(SD));
46   }
47 };
48 
49 template <>
50 struct GraphTraits<ScopDetectionWrapperPass *>
51     : public GraphTraits<ScopDetection *> {
52   static NodeRef getEntryNode(ScopDetectionWrapperPass *P) {
53     return GraphTraits<ScopDetection *>::getEntryNode(&P->getSD());
54   }
55   static nodes_iterator nodes_begin(ScopDetectionWrapperPass *P) {
56     return nodes_iterator::begin(getEntryNode(P));
57   }
58   static nodes_iterator nodes_end(ScopDetectionWrapperPass *P) {
59     return nodes_iterator::end(getEntryNode(P));
60   }
61 };
62 
63 template <> struct DOTGraphTraits<RegionNode *> : public DefaultDOTGraphTraits {
64   DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
65 
66   std::string getNodeLabel(RegionNode *Node, RegionNode *Graph) {
67     if (!Node->isSubRegion()) {
68       BasicBlock *BB = Node->getNodeAs<BasicBlock>();
69 
70       if (isSimple())
71         return DOTGraphTraits<DOTFuncInfo *>::getSimpleNodeLabel(BB, nullptr);
72 
73       else
74         return DOTGraphTraits<DOTFuncInfo *>::getCompleteNodeLabel(BB, nullptr);
75     }
76 
77     return "Not implemented";
78   }
79 };
80 
81 template <>
82 struct DOTGraphTraits<ScopDetectionWrapperPass *>
83     : public DOTGraphTraits<RegionNode *> {
84   DOTGraphTraits(bool isSimple = false)
85       : DOTGraphTraits<RegionNode *>(isSimple) {}
86   static std::string getGraphName(ScopDetectionWrapperPass *SD) {
87     return "Scop Graph";
88   }
89 
90   std::string getEdgeAttributes(RegionNode *srcNode,
91                                 GraphTraits<RegionInfo *>::ChildIteratorType CI,
92                                 ScopDetectionWrapperPass *P) {
93     RegionNode *destNode = *CI;
94     auto *SD = &P->getSD();
95 
96     if (srcNode->isSubRegion() || destNode->isSubRegion())
97       return "";
98 
99     // In case of a backedge, do not use it to define the layout of the nodes.
100     BasicBlock *srcBB = srcNode->getNodeAs<BasicBlock>();
101     BasicBlock *destBB = destNode->getNodeAs<BasicBlock>();
102 
103     RegionInfo *RI = SD->getRI();
104     Region *R = RI->getRegionFor(destBB);
105 
106     while (R && R->getParent())
107       if (R->getParent()->getEntry() == destBB)
108         R = R->getParent();
109       else
110         break;
111 
112     if (R && R->getEntry() == destBB && R->contains(srcBB))
113       return "constraint=false";
114 
115     return "";
116   }
117 
118   std::string getNodeLabel(RegionNode *Node, ScopDetectionWrapperPass *P) {
119     return DOTGraphTraits<RegionNode *>::getNodeLabel(
120         Node, reinterpret_cast<RegionNode *>(
121                   P->getSD().getRI()->getTopLevelRegion()));
122   }
123 
124   static std::string escapeString(std::string String) {
125     std::string Escaped;
126 
127     for (const auto &C : String) {
128       if (C == '"')
129         Escaped += '\\';
130 
131       Escaped += C;
132     }
133     return Escaped;
134   }
135 
136   // Print the cluster of the subregions. This groups the single basic blocks
137   // and adds a different background color for each group.
138   static void printRegionCluster(ScopDetection *SD, const Region *R,
139                                  raw_ostream &O, unsigned depth = 0) {
140     O.indent(2 * depth) << "subgraph cluster_" << static_cast<const void *>(R)
141                         << " {\n";
142     unsigned LineBegin, LineEnd;
143     std::string FileName;
144 
145     getDebugLocation(R, LineBegin, LineEnd, FileName);
146 
147     std::string Location;
148     if (LineBegin != (unsigned)-1) {
149       Location = escapeString(FileName + ":" + std::to_string(LineBegin) + "-" +
150                               std::to_string(LineEnd) + "\n");
151     }
152 
153     std::string ErrorMessage = SD->regionIsInvalidBecause(R);
154     ErrorMessage = escapeString(ErrorMessage);
155     O.indent(2 * (depth + 1))
156         << "label = \"" << Location << ErrorMessage << "\";\n";
157 
158     if (SD->isMaxRegionInScop(*R)) {
159       O.indent(2 * (depth + 1)) << "style = filled;\n";
160 
161       // Set color to green.
162       O.indent(2 * (depth + 1)) << "color = 3";
163     } else {
164       O.indent(2 * (depth + 1)) << "style = solid;\n";
165 
166       int color = (R->getDepth() * 2 % 12) + 1;
167 
168       // We do not want green again.
169       if (color == 3)
170         color = 6;
171 
172       O.indent(2 * (depth + 1)) << "color = " << color << "\n";
173     }
174 
175     for (const auto &SubRegion : *R)
176       printRegionCluster(SD, SubRegion.get(), O, depth + 1);
177 
178     RegionInfo *RI = R->getRegionInfo();
179 
180     for (BasicBlock *BB : R->blocks())
181       if (RI->getRegionFor(BB) == R)
182         O.indent(2 * (depth + 1))
183             << "Node"
184             << static_cast<void *>(RI->getTopLevelRegion()->getBBNode(BB))
185             << ";\n";
186 
187     O.indent(2 * depth) << "}\n";
188   }
189   static void
190   addCustomGraphFeatures(const ScopDetectionWrapperPass *SD,
191                          GraphWriter<ScopDetectionWrapperPass *> &GW) {
192     raw_ostream &O = GW.getOStream();
193     O << "\tcolorscheme = \"paired12\"\n";
194     printRegionCluster(&SD->getSD(), SD->getSD().getRI()->getTopLevelRegion(),
195                        O, 4);
196   }
197 };
198 } // end namespace llvm
199 
200 struct ScopViewer
201     : public DOTGraphTraitsViewer<ScopDetectionWrapperPass, false> {
202   static char ID;
203   ScopViewer()
204       : DOTGraphTraitsViewer<ScopDetectionWrapperPass, false>("scops", ID) {}
205   bool processFunction(Function &F, ScopDetectionWrapperPass &SD) override {
206     if (ViewFilter != "" && !F.getName().count(ViewFilter))
207       return false;
208 
209     if (ViewAll)
210       return true;
211 
212     // Check that at least one scop was detected.
213     return std::distance(SD.getSD().begin(), SD.getSD().end()) > 0;
214   }
215 };
216 char ScopViewer::ID = 0;
217 
218 struct ScopOnlyViewer
219     : public DOTGraphTraitsViewer<ScopDetectionWrapperPass, true> {
220   static char ID;
221   ScopOnlyViewer()
222       : DOTGraphTraitsViewer<ScopDetectionWrapperPass, true>("scopsonly", ID) {}
223 };
224 char ScopOnlyViewer::ID = 0;
225 
226 struct ScopPrinter
227     : public DOTGraphTraitsPrinter<ScopDetectionWrapperPass, false> {
228   static char ID;
229   ScopPrinter()
230       : DOTGraphTraitsPrinter<ScopDetectionWrapperPass, false>("scops", ID) {}
231 };
232 char ScopPrinter::ID = 0;
233 
234 struct ScopOnlyPrinter
235     : public DOTGraphTraitsPrinter<ScopDetectionWrapperPass, true> {
236   static char ID;
237   ScopOnlyPrinter()
238       : DOTGraphTraitsPrinter<ScopDetectionWrapperPass, true>("scopsonly", ID) {
239   }
240 };
241 char ScopOnlyPrinter::ID = 0;
242 
243 static RegisterPass<ScopViewer> X("view-scops",
244                                   "Polly - View Scops of function");
245 
246 static RegisterPass<ScopOnlyViewer>
247     Y("view-scops-only",
248       "Polly - View Scops of function (with no function bodies)");
249 
250 static RegisterPass<ScopPrinter> M("dot-scops",
251                                    "Polly - Print Scops of function");
252 
253 static RegisterPass<ScopOnlyPrinter>
254     N("dot-scops-only",
255       "Polly - Print Scops of function (with no function bodies)");
256 
257 Pass *polly::createDOTViewerPass() { return new ScopViewer(); }
258 
259 Pass *polly::createDOTOnlyViewerPass() { return new ScopOnlyViewer(); }
260 
261 Pass *polly::createDOTPrinterPass() { return new ScopPrinter(); }
262 
263 Pass *polly::createDOTOnlyPrinterPass() { return new ScopOnlyPrinter(); }
264