1//===- DDGPrinter.cpp - DOT printer for the data dependence graph ----------==//
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//===----------------------------------------------------------------------===//
10//
11// This file defines the `-dot-ddg` analysis pass, which emits DDG in DOT format
12// in a file named `ddg.<graph-name>.dot` for each loop in a function.
13//===----------------------------------------------------------------------===//
14
15#include "llvm/Analysis/DDGPrinter.h"
16#include "llvm/Support/CommandLine.h"
17#include "llvm/Support/GraphWriter.h"
18
19using namespace llvm;
20
21static cl::opt<bool> DotOnly("dot-ddg-only", cl::Hidden,
22 cl::desc("simple ddg dot graph"));
23static cl::opt<std::string> DDGDotFilenamePrefix(
24 "dot-ddg-filename-prefix", cl::init(Val: "ddg"), cl::Hidden,
25 cl::desc("The prefix used for the DDG dot file names."));
26
27static void writeDDGToDotFile(DataDependenceGraph &G, bool DOnly = false);
28
29//===--------------------------------------------------------------------===//
30// Implementation of DDG DOT Printer for a loop
31//===--------------------------------------------------------------------===//
32PreservedAnalyses DDGDotPrinterPass::run(Loop &L, LoopAnalysisManager &AM,
33 LoopStandardAnalysisResults &AR,
34 LPMUpdater &U) {
35 writeDDGToDotFile(G&: *AM.getResult<DDGAnalysis>(IR&: L, ExtraArgs&: AR), DOnly: DotOnly);
36 return PreservedAnalyses::all();
37}
38
39static void writeDDGToDotFile(DataDependenceGraph &G, bool DOnly) {
40 std::string Filename =
41 Twine(DDGDotFilenamePrefix + "." + G.getName() + ".dot").str();
42 errs() << "Writing '" << Filename << "'...";
43
44 std::error_code EC;
45 raw_fd_ostream File(Filename, EC, sys::fs::OF_Text);
46
47 if (!EC)
48 // We only provide the constant verson of the DOTGraphTrait specialization,
49 // hence the conversion to const pointer
50 WriteGraph(O&: File, G: (const DataDependenceGraph *)&G, ShortNames: DOnly);
51 else
52 errs() << " error opening file for writing!";
53 errs() << "\n";
54}
55
56//===--------------------------------------------------------------------===//
57// DDG DOT Printer Implementation
58//===--------------------------------------------------------------------===//
59std::string DDGDotGraphTraits::getNodeLabel(const DDGNode *Node,
60 const DataDependenceGraph *Graph) {
61 if (isSimple())
62 return getSimpleNodeLabel(Node, G: Graph);
63 else
64 return getVerboseNodeLabel(Node, G: Graph);
65}
66
67std::string DDGDotGraphTraits::getEdgeAttributes(
68 const DDGNode *Node, GraphTraits<const DDGNode *>::ChildIteratorType I,
69 const DataDependenceGraph *G) {
70 const DDGEdge *E = static_cast<const DDGEdge *>(*I.getCurrent());
71 if (isSimple())
72 return getSimpleEdgeAttributes(Src: Node, Edge: E, G);
73 else
74 return getVerboseEdgeAttributes(Src: Node, Edge: E, G);
75}
76
77bool DDGDotGraphTraits::isNodeHidden(const DDGNode *Node,
78 const DataDependenceGraph *Graph) {
79 if (isSimple() && isa<RootDDGNode>(Val: Node))
80 return true;
81 assert(Graph && "expected a valid graph pointer");
82 return Graph->getPiBlock(N: *Node) != nullptr;
83}
84
85std::string
86DDGDotGraphTraits::getSimpleNodeLabel(const DDGNode *Node,
87 const DataDependenceGraph *G) {
88 std::string Str;
89 raw_string_ostream OS(Str);
90 if (isa<SimpleDDGNode>(Val: Node))
91 for (auto *II : static_cast<const SimpleDDGNode *>(Node)->getInstructions())
92 OS << *II << "\n";
93 else if (isa<PiBlockDDGNode>(Val: Node))
94 OS << "pi-block\nwith\n"
95 << cast<PiBlockDDGNode>(Val: Node)->getNodes().size() << " nodes\n";
96 else if (isa<RootDDGNode>(Val: Node))
97 OS << "root\n";
98 else
99 llvm_unreachable("Unimplemented type of node");
100 return OS.str();
101}
102
103std::string
104DDGDotGraphTraits::getVerboseNodeLabel(const DDGNode *Node,
105 const DataDependenceGraph *G) {
106 std::string Str;
107 raw_string_ostream OS(Str);
108 OS << "<kind:" << Node->getKind() << ">\n";
109 if (isa<SimpleDDGNode>(Val: Node))
110 for (auto *II : static_cast<const SimpleDDGNode *>(Node)->getInstructions())
111 OS << *II << "\n";
112 else if (isa<PiBlockDDGNode>(Val: Node)) {
113 OS << "--- start of nodes in pi-block ---\n";
114 unsigned Count = 0;
115 const auto &PNodes = cast<PiBlockDDGNode>(Val: Node)->getNodes();
116 for (auto *PN : PNodes) {
117 OS << getVerboseNodeLabel(Node: PN, G);
118 if (++Count != PNodes.size())
119 OS << "\n";
120 }
121 OS << "--- end of nodes in pi-block ---\n";
122 } else if (isa<RootDDGNode>(Val: Node))
123 OS << "root\n";
124 else
125 llvm_unreachable("Unimplemented type of node");
126 return OS.str();
127}
128
129std::string DDGDotGraphTraits::getSimpleEdgeAttributes(
130 const DDGNode *Src, const DDGEdge *Edge, const DataDependenceGraph *G) {
131 std::string Str;
132 raw_string_ostream OS(Str);
133 DDGEdge::EdgeKind Kind = Edge->getKind();
134 OS << "label=\"[" << Kind << "]\"";
135 return OS.str();
136}
137
138std::string DDGDotGraphTraits::getVerboseEdgeAttributes(
139 const DDGNode *Src, const DDGEdge *Edge, const DataDependenceGraph *G) {
140 std::string Str;
141 raw_string_ostream OS(Str);
142 DDGEdge::EdgeKind Kind = Edge->getKind();
143 OS << "label=\"[";
144 if (Kind == DDGEdge::EdgeKind::MemoryDependence)
145 OS << G->getDependenceString(Src: *Src, Dst: Edge->getTargetNode());
146 else
147 OS << Kind;
148 OS << "]\"";
149 return OS.str();
150}
151