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comparison lib/TableGen/StringMatcher.cpp @ 147:c2174574ed3a

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LLVM 10
author Shinji KONO <kono@ie.u-ryukyu.ac.jp>
date Wed, 14 Aug 2019 16:55:33 +0900
parents 3a76565eade5
children
comparison
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134:3a76565eade5 147:c2174574ed3a
1 //===- StringMatcher.cpp - Generate a matcher for input strings -----------===// 1 //===- StringMatcher.cpp - Generate a matcher for input strings -----------===//
2 // 2 //
3 // The LLVM Compiler Infrastructure 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // 4 // See https://llvm.org/LICENSE.txt for license information.
5 // This file is distributed under the University of Illinois Open Source 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 // License. See LICENSE.TXT for details.
7 // 6 //
8 //===----------------------------------------------------------------------===// 7 //===----------------------------------------------------------------------===//
9 // 8 //
10 // This file implements the StringMatcher class. 9 // This file implements the StringMatcher class.
11 // 10 //
23 using namespace llvm; 22 using namespace llvm;
24 23
25 /// FindFirstNonCommonLetter - Find the first character in the keys of the 24 /// FindFirstNonCommonLetter - Find the first character in the keys of the
26 /// string pairs that is not shared across the whole set of strings. All 25 /// string pairs that is not shared across the whole set of strings. All
27 /// strings are assumed to have the same length. 26 /// strings are assumed to have the same length.
28 static unsigned 27 static unsigned
29 FindFirstNonCommonLetter(const std::vector<const 28 FindFirstNonCommonLetter(const std::vector<const
30 StringMatcher::StringPair*> &Matches) { 29 StringMatcher::StringPair*> &Matches) {
31 assert(!Matches.empty()); 30 assert(!Matches.empty());
32 for (unsigned i = 0, e = Matches[0]->first.size(); i != e; ++i) { 31 for (unsigned i = 0, e = Matches[0]->first.size(); i != e; ++i) {
33 // Check to see if letter i is the same across the set. 32 // Check to see if letter i is the same across the set.
34 char Letter = Matches[0]->first[i]; 33 char Letter = Matches[0]->first[i];
35 34
36 for (unsigned str = 0, e = Matches.size(); str != e; ++str) 35 for (unsigned str = 0, e = Matches.size(); str != e; ++str)
37 if (Matches[str]->first[i] != Letter) 36 if (Matches[str]->first[i] != Letter)
38 return i; 37 return i;
39 } 38 }
40 39
41 return Matches[0]->first.size(); 40 return Matches[0]->first.size();
42 } 41 }
43 42
44 /// EmitStringMatcherForChar - Given a set of strings that are known to be the 43 /// EmitStringMatcherForChar - Given a set of strings that are known to be the
45 /// same length and whose characters leading up to CharNo are the same, emit 44 /// same length and whose characters leading up to CharNo are the same, emit
49 bool StringMatcher::EmitStringMatcherForChar( 48 bool StringMatcher::EmitStringMatcherForChar(
50 const std::vector<const StringPair *> &Matches, unsigned CharNo, 49 const std::vector<const StringPair *> &Matches, unsigned CharNo,
51 unsigned IndentCount, bool IgnoreDuplicates) const { 50 unsigned IndentCount, bool IgnoreDuplicates) const {
52 assert(!Matches.empty() && "Must have at least one string to match!"); 51 assert(!Matches.empty() && "Must have at least one string to match!");
53 std::string Indent(IndentCount * 2 + 4, ' '); 52 std::string Indent(IndentCount * 2 + 4, ' ');
54 53
55 // If we have verified that the entire string matches, we're done: output the 54 // If we have verified that the entire string matches, we're done: output the
56 // matching code. 55 // matching code.
57 if (CharNo == Matches[0]->first.size()) { 56 if (CharNo == Matches[0]->first.size()) {
58 if (Matches.size() > 1 && !IgnoreDuplicates) 57 if (Matches.size() > 1 && !IgnoreDuplicates)
59 report_fatal_error("Had duplicate keys to match on"); 58 report_fatal_error("Had duplicate keys to match on");
60 59
61 // If the to-execute code has \n's in it, indent each subsequent line. 60 // If the to-execute code has \n's in it, indent each subsequent line.
62 StringRef Code = Matches[0]->second; 61 StringRef Code = Matches[0]->second;
63 62
64 std::pair<StringRef, StringRef> Split = Code.split('\n'); 63 std::pair<StringRef, StringRef> Split = Code.split('\n');
65 OS << Indent << Split.first << "\t // \"" << Matches[0]->first << "\"\n"; 64 OS << Indent << Split.first << "\t // \"" << Matches[0]->first << "\"\n";
66 65
67 Code = Split.second; 66 Code = Split.second;
68 while (!Code.empty()) { 67 while (!Code.empty()) {
70 OS << Indent << Split.first << "\n"; 69 OS << Indent << Split.first << "\n";
71 Code = Split.second; 70 Code = Split.second;
72 } 71 }
73 return false; 72 return false;
74 } 73 }
75 74
76 // Bucket the matches by the character we are comparing. 75 // Bucket the matches by the character we are comparing.
77 std::map<char, std::vector<const StringPair*>> MatchesByLetter; 76 std::map<char, std::vector<const StringPair*>> MatchesByLetter;
78 77
79 for (unsigned i = 0, e = Matches.size(); i != e; ++i) 78 for (unsigned i = 0, e = Matches.size(); i != e; ++i)
80 MatchesByLetter[Matches[i]->first[CharNo]].push_back(Matches[i]); 79 MatchesByLetter[Matches[i]->first[CharNo]].push_back(Matches[i]);
81 80
82 81
83 // If we have exactly one bucket to match, see how many characters are common 82 // If we have exactly one bucket to match, see how many characters are common
84 // across the whole set and match all of them at once. 83 // across the whole set and match all of them at once.
85 if (MatchesByLetter.size() == 1) { 84 if (MatchesByLetter.size() == 1) {
86 unsigned FirstNonCommonLetter = FindFirstNonCommonLetter(Matches); 85 unsigned FirstNonCommonLetter = FindFirstNonCommonLetter(Matches);
87 unsigned NumChars = FirstNonCommonLetter-CharNo; 86 unsigned NumChars = FirstNonCommonLetter-CharNo;
88 87
89 // Emit code to break out if the prefix doesn't match. 88 // Emit code to break out if the prefix doesn't match.
90 if (NumChars == 1) { 89 if (NumChars == 1) {
91 // Do the comparison with if (Str[1] != 'f') 90 // Do the comparison with if (Str[1] != 'f')
92 // FIXME: Need to escape general characters. 91 // FIXME: Need to escape general characters.
93 OS << Indent << "if (" << StrVariableName << "[" << CharNo << "] != '" 92 OS << Indent << "if (" << StrVariableName << "[" << CharNo << "] != '"
103 } 102 }
104 103
105 return EmitStringMatcherForChar(Matches, FirstNonCommonLetter, IndentCount, 104 return EmitStringMatcherForChar(Matches, FirstNonCommonLetter, IndentCount,
106 IgnoreDuplicates); 105 IgnoreDuplicates);
107 } 106 }
108 107
109 // Otherwise, we have multiple possible things, emit a switch on the 108 // Otherwise, we have multiple possible things, emit a switch on the
110 // character. 109 // character.
111 OS << Indent << "switch (" << StrVariableName << "[" << CharNo << "]) {\n"; 110 OS << Indent << "switch (" << StrVariableName << "[" << CharNo << "]) {\n";
112 OS << Indent << "default: break;\n"; 111 OS << Indent << "default: break;\n";
113 112
114 for (std::map<char, std::vector<const StringPair*>>::iterator LI = 113 for (std::map<char, std::vector<const StringPair*>>::iterator LI =
115 MatchesByLetter.begin(), E = MatchesByLetter.end(); LI != E; ++LI) { 114 MatchesByLetter.begin(), E = MatchesByLetter.end(); LI != E; ++LI) {
116 // TODO: escape hard stuff (like \n) if we ever care about it. 115 // TODO: escape hard stuff (like \n) if we ever care about it.
117 OS << Indent << "case '" << LI->first << "':\t // " 116 OS << Indent << "case '" << LI->first << "':\t // "
118 << LI->second.size() << " string"; 117 << LI->second.size() << " string";
119 if (LI->second.size() != 1) OS << 's'; 118 if (LI->second.size() != 1) OS << 's';
120 OS << " to match.\n"; 119 OS << " to match.\n";
121 if (EmitStringMatcherForChar(LI->second, CharNo + 1, IndentCount + 1, 120 if (EmitStringMatcherForChar(LI->second, CharNo + 1, IndentCount + 1,
122 IgnoreDuplicates)) 121 IgnoreDuplicates))
123 OS << Indent << " break;\n"; 122 OS << Indent << " break;\n";
124 } 123 }
125 124
126 OS << Indent << "}\n"; 125 OS << Indent << "}\n";
127 return true; 126 return true;
128 } 127 }
129 128
130 /// Emit - Top level entry point. 129 /// Emit - Top level entry point.
131 /// 130 ///
132 void StringMatcher::Emit(unsigned Indent, bool IgnoreDuplicates) const { 131 void StringMatcher::Emit(unsigned Indent, bool IgnoreDuplicates) const {
133 // If nothing to match, just fall through. 132 // If nothing to match, just fall through.
134 if (Matches.empty()) return; 133 if (Matches.empty()) return;
135 134
136 // First level categorization: group strings by length. 135 // First level categorization: group strings by length.
137 std::map<unsigned, std::vector<const StringPair*>> MatchesByLength; 136 std::map<unsigned, std::vector<const StringPair*>> MatchesByLength;
138 137
139 for (unsigned i = 0, e = Matches.size(); i != e; ++i) 138 for (unsigned i = 0, e = Matches.size(); i != e; ++i)
140 MatchesByLength[Matches[i].first.size()].push_back(&Matches[i]); 139 MatchesByLength[Matches[i].first.size()].push_back(&Matches[i]);
141 140
142 // Output a switch statement on length and categorize the elements within each 141 // Output a switch statement on length and categorize the elements within each
143 // bin. 142 // bin.
144 OS.indent(Indent*2+2) << "switch (" << StrVariableName << ".size()) {\n"; 143 OS.indent(Indent*2+2) << "switch (" << StrVariableName << ".size()) {\n";
145 OS.indent(Indent*2+2) << "default: break;\n"; 144 OS.indent(Indent*2+2) << "default: break;\n";
146 145
147 for (std::map<unsigned, std::vector<const StringPair*>>::iterator LI = 146 for (std::map<unsigned, std::vector<const StringPair*>>::iterator LI =
148 MatchesByLength.begin(), E = MatchesByLength.end(); LI != E; ++LI) { 147 MatchesByLength.begin(), E = MatchesByLength.end(); LI != E; ++LI) {
149 OS.indent(Indent*2+2) << "case " << LI->first << ":\t // " 148 OS.indent(Indent*2+2) << "case " << LI->first << ":\t // "
150 << LI->second.size() 149 << LI->second.size()
151 << " string" << (LI->second.size() == 1 ? "" : "s") << " to match.\n"; 150 << " string" << (LI->second.size() == 1 ? "" : "s") << " to match.\n";
152 if (EmitStringMatcherForChar(LI->second, 0, Indent, IgnoreDuplicates)) 151 if (EmitStringMatcherForChar(LI->second, 0, Indent, IgnoreDuplicates))
153 OS.indent(Indent*2+4) << "break;\n"; 152 OS.indent(Indent*2+4) << "break;\n";
154 } 153 }
155 154
156 OS.indent(Indent*2+2) << "}\n"; 155 OS.indent(Indent*2+2) << "}\n";
157 } 156 }