1 //===- MacroInfo.cpp - Information about #defined identifiers -------------===//
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 // This file implements the MacroInfo interface.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "clang/Lex/MacroInfo.h"
14 #include "clang/Basic/IdentifierTable.h"
15 #include "clang/Basic/LLVM.h"
16 #include "clang/Basic/SourceLocation.h"
17 #include "clang/Basic/SourceManager.h"
18 #include "clang/Basic/TokenKinds.h"
19 #include "clang/Lex/Preprocessor.h"
20 #include "clang/Lex/Token.h"
21 #include "llvm/ADT/Optional.h"
22 #include "llvm/ADT/StringRef.h"
23 #include "llvm/Support/Casting.h"
24 #include "llvm/Support/Compiler.h"
25 #include "llvm/Support/raw_ostream.h"
26 #include <cassert>
27 #include <utility>
28 
29 using namespace clang;
30 
31 MacroInfo::MacroInfo(SourceLocation DefLoc)
32     : Location(DefLoc), IsDefinitionLengthCached(false), IsFunctionLike(false),
33       IsC99Varargs(false), IsGNUVarargs(false), IsBuiltinMacro(false),
34       HasCommaPasting(false), IsDisabled(false), IsUsed(false),
35       IsAllowRedefinitionsWithoutWarning(false), IsWarnIfUnused(false),
36       UsedForHeaderGuard(false) {}
37 
38 unsigned MacroInfo::getDefinitionLengthSlow(const SourceManager &SM) const {
39   assert(!IsDefinitionLengthCached);
40   IsDefinitionLengthCached = true;
41 
42   if (ReplacementTokens.empty())
43     return (DefinitionLength = 0);
44 
45   const Token &firstToken = ReplacementTokens.front();
46   const Token &lastToken = ReplacementTokens.back();
47   SourceLocation macroStart = firstToken.getLocation();
48   SourceLocation macroEnd = lastToken.getLocation();
49   assert(macroStart.isValid() && macroEnd.isValid());
50   assert((macroStart.isFileID() || firstToken.is(tok::comment)) &&
51          "Macro defined in macro?");
52   assert((macroEnd.isFileID() || lastToken.is(tok::comment)) &&
53          "Macro defined in macro?");
54   std::pair<FileID, unsigned>
55       startInfo = SM.getDecomposedExpansionLoc(macroStart);
56   std::pair<FileID, unsigned>
57       endInfo = SM.getDecomposedExpansionLoc(macroEnd);
58   assert(startInfo.first == endInfo.first &&
59          "Macro definition spanning multiple FileIDs ?");
60   assert(startInfo.second <= endInfo.second);
61   DefinitionLength = endInfo.second - startInfo.second;
62   DefinitionLength += lastToken.getLength();
63 
64   return DefinitionLength;
65 }
66 
67 /// Return true if the specified macro definition is equal to
68 /// this macro in spelling, arguments, and whitespace.
69 ///
70 /// \param Syntactically if true, the macro definitions can be identical even
71 /// if they use different identifiers for the function macro parameters.
72 /// Otherwise the comparison is lexical and this implements the rules in
73 /// C99 6.10.3.
74 bool MacroInfo::isIdenticalTo(const MacroInfo &Other, Preprocessor &PP,
75                               bool Syntactically) const {
76   bool Lexically = !Syntactically;
77 
78   // Check # tokens in replacement, number of args, and various flags all match.
79   if (ReplacementTokens.size() != Other.ReplacementTokens.size() ||
80       getNumParams() != Other.getNumParams() ||
81       isFunctionLike() != Other.isFunctionLike() ||
82       isC99Varargs() != Other.isC99Varargs() ||
83       isGNUVarargs() != Other.isGNUVarargs())
84     return false;
85 
86   if (Lexically) {
87     // Check arguments.
88     for (param_iterator I = param_begin(), OI = Other.param_begin(),
89                         E = param_end();
90          I != E; ++I, ++OI)
91       if (*I != *OI) return false;
92   }
93 
94   // Check all the tokens.
95   for (unsigned i = 0, e = ReplacementTokens.size(); i != e; ++i) {
96     const Token &A = ReplacementTokens[i];
97     const Token &B = Other.ReplacementTokens[i];
98     if (A.getKind() != B.getKind())
99       return false;
100 
101     // If this isn't the first first token, check that the whitespace and
102     // start-of-line characteristics match.
103     if (i != 0 &&
104         (A.isAtStartOfLine() != B.isAtStartOfLine() ||
105          A.hasLeadingSpace() != B.hasLeadingSpace()))
106       return false;
107 
108     // If this is an identifier, it is easy.
109     if (A.getIdentifierInfo() || B.getIdentifierInfo()) {
110       if (A.getIdentifierInfo() == B.getIdentifierInfo())
111         continue;
112       if (Lexically)
113         return false;
114       // With syntactic equivalence the parameter names can be different as long
115       // as they are used in the same place.
116       int AArgNum = getParameterNum(A.getIdentifierInfo());
117       if (AArgNum == -1)
118         return false;
119       if (AArgNum != Other.getParameterNum(B.getIdentifierInfo()))
120         return false;
121       continue;
122     }
123 
124     // Otherwise, check the spelling.
125     if (PP.getSpelling(A) != PP.getSpelling(B))
126       return false;
127   }
128 
129   return true;
130 }
131 
132 LLVM_DUMP_METHOD void MacroInfo::dump() const {
133   llvm::raw_ostream &Out = llvm::errs();
134 
135   // FIXME: Dump locations.
136   Out << "MacroInfo " << this;
137   if (IsBuiltinMacro) Out << " builtin";
138   if (IsDisabled) Out << " disabled";
139   if (IsUsed) Out << " used";
140   if (IsAllowRedefinitionsWithoutWarning)
141     Out << " allow_redefinitions_without_warning";
142   if (IsWarnIfUnused) Out << " warn_if_unused";
143   if (UsedForHeaderGuard) Out << " header_guard";
144 
145   Out << "\n    #define <macro>";
146   if (IsFunctionLike) {
147     Out << "(";
148     for (unsigned I = 0; I != NumParameters; ++I) {
149       if (I) Out << ", ";
150       Out << ParameterList[I]->getName();
151     }
152     if (IsC99Varargs || IsGNUVarargs) {
153       if (NumParameters && IsC99Varargs) Out << ", ";
154       Out << "...";
155     }
156     Out << ")";
157   }
158 
159   bool First = true;
160   for (const Token &Tok : ReplacementTokens) {
161     // Leading space is semantically meaningful in a macro definition,
162     // so preserve it in the dump output.
163     if (First || Tok.hasLeadingSpace())
164       Out << " ";
165     First = false;
166 
167     if (const char *Punc = tok::getPunctuatorSpelling(Tok.getKind()))
168       Out << Punc;
169     else if (Tok.isLiteral() && Tok.getLiteralData())
170       Out << StringRef(Tok.getLiteralData(), Tok.getLength());
171     else if (auto *II = Tok.getIdentifierInfo())
172       Out << II->getName();
173     else
174       Out << Tok.getName();
175   }
176 }
177 
178 MacroDirective::DefInfo MacroDirective::getDefinition() {
179   MacroDirective *MD = this;
180   SourceLocation UndefLoc;
181   Optional<bool> isPublic;
182   for (; MD; MD = MD->getPrevious()) {
183     if (DefMacroDirective *DefMD = dyn_cast<DefMacroDirective>(MD))
184       return DefInfo(DefMD, UndefLoc,
185                      !isPublic.hasValue() || isPublic.getValue());
186 
187     if (UndefMacroDirective *UndefMD = dyn_cast<UndefMacroDirective>(MD)) {
188       UndefLoc = UndefMD->getLocation();
189       continue;
190     }
191 
192     VisibilityMacroDirective *VisMD = cast<VisibilityMacroDirective>(MD);
193     if (!isPublic.hasValue())
194       isPublic = VisMD->isPublic();
195   }
196 
197   return DefInfo(nullptr, UndefLoc,
198                  !isPublic.hasValue() || isPublic.getValue());
199 }
200 
201 const MacroDirective::DefInfo
202 MacroDirective::findDirectiveAtLoc(SourceLocation L,
203                                    const SourceManager &SM) const {
204   assert(L.isValid() && "SourceLocation is invalid.");
205   for (DefInfo Def = getDefinition(); Def; Def = Def.getPreviousDefinition()) {
206     if (Def.getLocation().isInvalid() ||  // For macros defined on the command line.
207         SM.isBeforeInTranslationUnit(Def.getLocation(), L))
208       return (!Def.isUndefined() ||
209               SM.isBeforeInTranslationUnit(L, Def.getUndefLocation()))
210                   ? Def : DefInfo();
211   }
212   return DefInfo();
213 }
214 
215 LLVM_DUMP_METHOD void MacroDirective::dump() const {
216   llvm::raw_ostream &Out = llvm::errs();
217 
218   switch (getKind()) {
219   case MD_Define: Out << "DefMacroDirective"; break;
220   case MD_Undefine: Out << "UndefMacroDirective"; break;
221   case MD_Visibility: Out << "VisibilityMacroDirective"; break;
222   }
223   Out << " " << this;
224   // FIXME: Dump SourceLocation.
225   if (auto *Prev = getPrevious())
226     Out << " prev " << Prev;
227   if (IsFromPCH) Out << " from_pch";
228 
229   if (isa<VisibilityMacroDirective>(this))
230     Out << (IsPublic ? " public" : " private");
231 
232   if (auto *DMD = dyn_cast<DefMacroDirective>(this)) {
233     if (auto *Info = DMD->getInfo()) {
234       Out << "\n  ";
235       Info->dump();
236     }
237   }
238   Out << "\n";
239 }
240 
241 ModuleMacro *ModuleMacro::create(Preprocessor &PP, Module *OwningModule,
242                                  IdentifierInfo *II, MacroInfo *Macro,
243                                  ArrayRef<ModuleMacro *> Overrides) {
244   void *Mem = PP.getPreprocessorAllocator().Allocate(
245       sizeof(ModuleMacro) + sizeof(ModuleMacro *) * Overrides.size(),
246       alignof(ModuleMacro));
247   return new (Mem) ModuleMacro(OwningModule, II, Macro, Overrides);
248 }
249