1//===--- MacroArgs.cpp - Formal argument info for Macros ------------------===//
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 MacroArgs interface.
10//
11//===----------------------------------------------------------------------===//
12
13#include "clang/Lex/MacroArgs.h"
14#include "clang/Lex/LexDiagnostic.h"
15#include "clang/Lex/MacroInfo.h"
16#include "clang/Lex/Preprocessor.h"
17#include "llvm/ADT/SmallString.h"
18#include "llvm/Support/SaveAndRestore.h"
19#include <algorithm>
20
21using namespace clang;
22
23/// MacroArgs ctor function - This destroys the vector passed in.
24MacroArgs *MacroArgs::create(const MacroInfo *MI,
25 ArrayRef<Token> UnexpArgTokens,
26 bool VarargsElided, Preprocessor &PP) {
27 assert(MI->isFunctionLike() &&
28 "Can't have args for an object-like macro!");
29 MacroArgs **ResultEnt = nullptr;
30 unsigned ClosestMatch = ~0U;
31
32 // See if we have an entry with a big enough argument list to reuse on the
33 // free list. If so, reuse it.
34 for (MacroArgs **Entry = &PP.MacroArgCache; *Entry;
35 Entry = &(*Entry)->ArgCache) {
36 if ((*Entry)->NumUnexpArgTokens >= UnexpArgTokens.size() &&
37 (*Entry)->NumUnexpArgTokens < ClosestMatch) {
38 ResultEnt = Entry;
39
40 // If we have an exact match, use it.
41 if ((*Entry)->NumUnexpArgTokens == UnexpArgTokens.size())
42 break;
43 // Otherwise, use the best fit.
44 ClosestMatch = (*Entry)->NumUnexpArgTokens;
45 }
46 }
47 MacroArgs *Result;
48 if (!ResultEnt) {
49 // Allocate memory for a MacroArgs object with the lexer tokens at the end,
50 // and construct the MacroArgs object.
51 Result = new (
52 llvm::safe_malloc(Sz: totalSizeToAlloc<Token>(Counts: UnexpArgTokens.size())))
53 MacroArgs(UnexpArgTokens.size(), VarargsElided, MI->getNumParams());
54 } else {
55 Result = *ResultEnt;
56 // Unlink this node from the preprocessors singly linked list.
57 *ResultEnt = Result->ArgCache;
58 Result->NumUnexpArgTokens = UnexpArgTokens.size();
59 Result->VarargsElided = VarargsElided;
60 Result->NumMacroArgs = MI->getNumParams();
61 }
62
63 // Copy the actual unexpanded tokens to immediately after the result ptr.
64 if (!UnexpArgTokens.empty()) {
65 static_assert(std::is_trivial_v<Token>,
66 "assume trivial copyability if copying into the "
67 "uninitialized array (as opposed to reusing a cached "
68 "MacroArgs)");
69 std::copy(UnexpArgTokens.begin(), UnexpArgTokens.end(),
70 Result->getTrailingObjects<Token>());
71 }
72
73 return Result;
74}
75
76/// destroy - Destroy and deallocate the memory for this object.
77///
78void MacroArgs::destroy(Preprocessor &PP) {
79 // Don't clear PreExpArgTokens, just clear the entries. Clearing the entries
80 // would deallocate the element vectors.
81 for (unsigned i = 0, e = PreExpArgTokens.size(); i != e; ++i)
82 PreExpArgTokens[i].clear();
83
84 // Add this to the preprocessor's free list.
85 ArgCache = PP.MacroArgCache;
86 PP.MacroArgCache = this;
87}
88
89/// deallocate - This should only be called by the Preprocessor when managing
90/// its freelist.
91MacroArgs *MacroArgs::deallocate() {
92 MacroArgs *Next = ArgCache;
93
94 // Run the dtor to deallocate the vectors.
95 this->~MacroArgs();
96 // Release the memory for the object.
97 static_assert(std::is_trivially_destructible_v<Token>,
98 "assume trivially destructible and forego destructors");
99 free(ptr: this);
100
101 return Next;
102}
103
104
105/// getArgLength - Given a pointer to an expanded or unexpanded argument,
106/// return the number of tokens, not counting the EOF, that make up the
107/// argument.
108unsigned MacroArgs::getArgLength(const Token *ArgPtr) {
109 unsigned NumArgTokens = 0;
110 for (; ArgPtr->isNot(K: tok::eof); ++ArgPtr)
111 ++NumArgTokens;
112 return NumArgTokens;
113}
114
115
116/// getUnexpArgument - Return the unexpanded tokens for the specified formal.
117///
118const Token *MacroArgs::getUnexpArgument(unsigned Arg) const {
119
120 assert(Arg < getNumMacroArguments() && "Invalid arg #");
121 // The unexpanded argument tokens start immediately after the MacroArgs object
122 // in memory.
123 const Token *Start = getTrailingObjects<Token>();
124 const Token *Result = Start;
125
126 // Scan to find Arg.
127 for (; Arg; ++Result) {
128 assert(Result < Start+NumUnexpArgTokens && "Invalid arg #");
129 if (Result->is(K: tok::eof))
130 --Arg;
131 }
132 assert(Result < Start+NumUnexpArgTokens && "Invalid arg #");
133 return Result;
134}
135
136bool MacroArgs::invokedWithVariadicArgument(const MacroInfo *const MI,
137 Preprocessor &PP) {
138 if (!MI->isVariadic())
139 return false;
140 const int VariadicArgIndex = getNumMacroArguments() - 1;
141 return getPreExpArgument(Arg: VariadicArgIndex, PP).front().isNot(K: tok::eof);
142}
143
144/// ArgNeedsPreexpansion - If we can prove that the argument won't be affected
145/// by pre-expansion, return false. Otherwise, conservatively return true.
146bool MacroArgs::ArgNeedsPreexpansion(const Token *ArgTok,
147 Preprocessor &PP) const {
148 // If there are no identifiers in the argument list, or if the identifiers are
149 // known to not be macros, pre-expansion won't modify it.
150 for (; ArgTok->isNot(K: tok::eof); ++ArgTok)
151 if (IdentifierInfo *II = ArgTok->getIdentifierInfo())
152 if (II->hasMacroDefinition())
153 // Return true even though the macro could be a function-like macro
154 // without a following '(' token, or could be disabled, or not visible.
155 return true;
156 return false;
157}
158
159/// getPreExpArgument - Return the pre-expanded form of the specified
160/// argument.
161const std::vector<Token> &MacroArgs::getPreExpArgument(unsigned Arg,
162 Preprocessor &PP) {
163 assert(Arg < getNumMacroArguments() && "Invalid argument number!");
164
165 // If we have already computed this, return it.
166 if (PreExpArgTokens.size() < getNumMacroArguments())
167 PreExpArgTokens.resize(new_size: getNumMacroArguments());
168
169 std::vector<Token> &Result = PreExpArgTokens[Arg];
170 if (!Result.empty()) return Result;
171
172 SaveAndRestore PreExpandingMacroArgs(PP.InMacroArgPreExpansion, true);
173
174 const Token *AT = getUnexpArgument(Arg);
175 unsigned NumToks = getArgLength(ArgPtr: AT)+1; // Include the EOF.
176
177 // Otherwise, we have to pre-expand this argument, populating Result. To do
178 // this, we set up a fake TokenLexer to lex from the unexpanded argument
179 // list. With this installed, we lex expanded tokens until we hit the EOF
180 // token at the end of the unexp list.
181 PP.EnterTokenStream(Toks: AT, NumToks, DisableMacroExpansion: false /*disable expand*/,
182 OwnsTokens: false /*owns tokens*/, IsReinject: false /*is reinject*/);
183
184 // Lex all of the macro-expanded tokens into Result.
185 do {
186 Result.push_back(x: Token());
187 Token &Tok = Result.back();
188 PP.Lex(Result&: Tok);
189 } while (Result.back().isNot(K: tok::eof));
190
191 // Pop the token stream off the top of the stack. We know that the internal
192 // pointer inside of it is to the "end" of the token stream, but the stack
193 // will not otherwise be popped until the next token is lexed. The problem is
194 // that the token may be lexed sometime after the vector of tokens itself is
195 // destroyed, which would be badness.
196 if (PP.InCachingLexMode())
197 PP.ExitCachingLexMode();
198 PP.RemoveTopOfLexerStack();
199 return Result;
200}
201
202
203/// StringifyArgument - Implement C99 6.10.3.2p2, converting a sequence of
204/// tokens into the literal string token that should be produced by the C #
205/// preprocessor operator. If Charify is true, then it should be turned into
206/// a character literal for the Microsoft charize (#@) extension.
207///
208Token MacroArgs::StringifyArgument(const Token *ArgToks,
209 Preprocessor &PP, bool Charify,
210 SourceLocation ExpansionLocStart,
211 SourceLocation ExpansionLocEnd) {
212 Token Tok;
213 Tok.startToken();
214 Tok.setKind(Charify ? tok::char_constant : tok::string_literal);
215
216 const Token *ArgTokStart = ArgToks;
217
218 // Stringify all the tokens.
219 SmallString<128> Result;
220 Result += "\"";
221
222 bool isFirst = true;
223 for (; ArgToks->isNot(K: tok::eof); ++ArgToks) {
224 const Token &Tok = *ArgToks;
225 if (!isFirst && (Tok.hasLeadingSpace() || Tok.isAtStartOfLine()))
226 Result += ' ';
227 isFirst = false;
228
229 // If this is a string or character constant, escape the token as specified
230 // by 6.10.3.2p2.
231 if (tok::isStringLiteral(K: Tok.getKind()) || // "foo", u8R"x(foo)x"_bar, etc.
232 Tok.is(K: tok::char_constant) || // 'x'
233 Tok.is(K: tok::wide_char_constant) || // L'x'.
234 Tok.is(K: tok::utf8_char_constant) || // u8'x'.
235 Tok.is(K: tok::utf16_char_constant) || // u'x'.
236 Tok.is(K: tok::utf32_char_constant)) { // U'x'.
237 bool Invalid = false;
238 std::string TokStr = PP.getSpelling(Tok, Invalid: &Invalid);
239 if (!Invalid) {
240 std::string Str = Lexer::Stringify(Str: TokStr);
241 Result.append(in_start: Str.begin(), in_end: Str.end());
242 }
243 } else if (Tok.is(K: tok::code_completion)) {
244 PP.CodeCompleteNaturalLanguage();
245 } else {
246 // Otherwise, just append the token. Do some gymnastics to get the token
247 // in place and avoid copies where possible.
248 unsigned CurStrLen = Result.size();
249 Result.resize(N: CurStrLen+Tok.getLength());
250 const char *BufPtr = Result.data() + CurStrLen;
251 bool Invalid = false;
252 unsigned ActualTokLen = PP.getSpelling(Tok, Buffer&: BufPtr, Invalid: &Invalid);
253
254 if (!Invalid) {
255 // If getSpelling returned a pointer to an already uniqued version of
256 // the string instead of filling in BufPtr, memcpy it onto our string.
257 if (ActualTokLen && BufPtr != &Result[CurStrLen])
258 memcpy(dest: &Result[CurStrLen], src: BufPtr, n: ActualTokLen);
259
260 // If the token was dirty, the spelling may be shorter than the token.
261 if (ActualTokLen != Tok.getLength())
262 Result.resize(N: CurStrLen+ActualTokLen);
263 }
264 }
265 }
266
267 // If the last character of the string is a \, and if it isn't escaped, this
268 // is an invalid string literal, diagnose it as specified in C99.
269 if (Result.back() == '\\') {
270 // Count the number of consecutive \ characters. If even, then they are
271 // just escaped backslashes, otherwise it's an error.
272 unsigned FirstNonSlash = Result.size()-2;
273 // Guaranteed to find the starting " if nothing else.
274 while (Result[FirstNonSlash] == '\\')
275 --FirstNonSlash;
276 if ((Result.size()-1-FirstNonSlash) & 1) {
277 // Diagnose errors for things like: #define F(X) #X / F(\)
278 PP.Diag(Tok: ArgToks[-1], DiagID: diag::pp_invalid_string_literal);
279 Result.pop_back(); // remove one of the \'s.
280 }
281 }
282 Result += '"';
283
284 // If this is the charify operation and the result is not a legal character
285 // constant, diagnose it.
286 if (Charify) {
287 // First step, turn double quotes into single quotes:
288 Result[0] = '\'';
289 Result[Result.size()-1] = '\'';
290
291 // Check for bogus character.
292 bool isBad = false;
293 if (Result.size() == 3)
294 isBad = Result[1] == '\''; // ''' is not legal. '\' already fixed above.
295 else
296 isBad = (Result.size() != 4 || Result[1] != '\\'); // Not '\x'
297
298 if (isBad) {
299 PP.Diag(Tok: ArgTokStart[0], DiagID: diag::err_invalid_character_to_charify);
300 Result = "' '"; // Use something arbitrary, but legal.
301 }
302 }
303
304 PP.CreateString(Str: Result, Tok,
305 ExpansionLocStart, ExpansionLocEnd);
306 return Tok;
307}
308