//===--- MacroArgs.cpp - Formal argument info for Macros ------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the MacroArgs interface.
//
//===----------------------------------------------------------------------===//
#include "clang/Lex/MacroArgs.h"
#include "clang/Lex/LexDiagnostic.h"
#include "clang/Lex/MacroInfo.h"
#include "clang/Lex/Preprocessor.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/SaveAndRestore.h"
#include <algorithm>
using namespace clang;
/// MacroArgs ctor function - This destroys the vector passed in.
MacroArgs *MacroArgs::create(const MacroInfo *MI,
ArrayRef<Token> UnexpArgTokens,
bool VarargsElided, Preprocessor &PP) {
assert(MI->isFunctionLike() &&
"Can't have args for an object-like macro!");
MacroArgs **ResultEnt = nullptr;
unsigned ClosestMatch = ~0U;
// See if we have an entry with a big enough argument list to reuse on the
// free list. If so, reuse it.
for (MacroArgs **Entry = &PP.MacroArgCache; *Entry;
Entry = &(*Entry)->ArgCache) {
if ((*Entry)->NumUnexpArgTokens >= UnexpArgTokens.size() &&
(*Entry)->NumUnexpArgTokens < ClosestMatch) {
ResultEnt = Entry;
// If we have an exact match, use it.
if ((*Entry)->NumUnexpArgTokens == UnexpArgTokens.size())
break;
// Otherwise, use the best fit.
ClosestMatch = (*Entry)->NumUnexpArgTokens;
}
}
MacroArgs *Result;
if (!ResultEnt) {
// Allocate memory for a MacroArgs object with the lexer tokens at the end,
// and construct the MacroArgs object.
Result = new (
llvm::safe_malloc(totalSizeToAlloc<Token>(UnexpArgTokens.size())))
MacroArgs(UnexpArgTokens.size(), VarargsElided, MI->getNumParams());
} else {
Result = *ResultEnt;
// Unlink this node from the preprocessors singly linked list.
*ResultEnt = Result->ArgCache;
Result->NumUnexpArgTokens = UnexpArgTokens.size();
Result->VarargsElided = VarargsElided;
Result->NumMacroArgs = MI->getNumParams();
}
// Copy the actual unexpanded tokens to immediately after the result ptr.
if (!UnexpArgTokens.empty()) {
static_assert(std::is_trivial<Token>::value,
"assume trivial copyability if copying into the "
"uninitialized array (as opposed to reusing a cached "
"MacroArgs)");
std::copy(UnexpArgTokens.begin(), UnexpArgTokens.end(),
Result->getTrailingObjects<Token>());
}
return Result;
}
/// destroy - Destroy and deallocate the memory for this object.
///
void MacroArgs::destroy(Preprocessor &PP) {
// Don't clear PreExpArgTokens, just clear the entries. Clearing the entries
// would deallocate the element vectors.
for (unsigned i = 0, e = PreExpArgTokens.size(); i != e; ++i)
PreExpArgTokens[i].clear();
// Add this to the preprocessor's free list.
ArgCache = PP.MacroArgCache;
PP.MacroArgCache = this;
}
/// deallocate - This should only be called by the Preprocessor when managing
/// its freelist.
MacroArgs *MacroArgs::deallocate() {
MacroArgs *Next = ArgCache;
// Run the dtor to deallocate the vectors.
this->~MacroArgs();
// Release the memory for the object.
static_assert(std::is_trivially_destructible<Token>::value,
"assume trivially destructible and forego destructors");
free(this);
return Next;
}
/// getArgLength - Given a pointer to an expanded or unexpanded argument,
/// return the number of tokens, not counting the EOF, that make up the
/// argument.
unsigned MacroArgs::getArgLength(const Token *ArgPtr) {
unsigned NumArgTokens = 0;
for (; ArgPtr->isNot(tok::eof); ++ArgPtr)
++NumArgTokens;
return NumArgTokens;
}
/// getUnexpArgument - Return the unexpanded tokens for the specified formal.
///
const Token *MacroArgs::getUnexpArgument(unsigned Arg) const {
assert(Arg < getNumMacroArguments() && "Invalid arg #");
// The unexpanded argument tokens start immediately after the MacroArgs object
// in memory.
const Token *Start = getTrailingObjects<Token>();
const Token *Result = Start;
// Scan to find Arg.
for (; Arg; ++Result) {
assert(Result < Start+NumUnexpArgTokens && "Invalid arg #");
if (Result->is(tok::eof))
--Arg;
}
assert(Result < Start+NumUnexpArgTokens && "Invalid arg #");
return Result;
}
bool MacroArgs::invokedWithVariadicArgument(const MacroInfo *const MI,
Preprocessor &PP) {
if (!MI->isVariadic())
return false;
const int VariadicArgIndex = getNumMacroArguments() - 1;
return getPreExpArgument(VariadicArgIndex, PP).front().isNot(tok::eof);
}
/// ArgNeedsPreexpansion - If we can prove that the argument won't be affected
/// by pre-expansion, return false. Otherwise, conservatively return true.
bool MacroArgs::ArgNeedsPreexpansion(const Token *ArgTok,
Preprocessor &PP) const {
// If there are no identifiers in the argument list, or if the identifiers are
// known to not be macros, pre-expansion won't modify it.
for (; ArgTok->isNot(tok::eof); ++ArgTok)
if (IdentifierInfo *II = ArgTok->getIdentifierInfo())
if (II->hasMacroDefinition())
// Return true even though the macro could be a function-like macro
// without a following '(' token, or could be disabled, or not visible.
return true;
return false;
}
/// getPreExpArgument - Return the pre-expanded form of the specified
/// argument.
const std::vector<Token> &MacroArgs::getPreExpArgument(unsigned Arg,
Preprocessor &PP) {
assert(Arg < getNumMacroArguments() && "Invalid argument number!");
// If we have already computed this, return it.
if (PreExpArgTokens.size() < getNumMacroArguments())
PreExpArgTokens.resize(getNumMacroArguments());
std::vector<Token> &Result = PreExpArgTokens[Arg];
if (!Result.empty()) return Result;
SaveAndRestore<bool> PreExpandingMacroArgs(PP.InMacroArgPreExpansion, true);
const Token *AT = getUnexpArgument(Arg);
unsigned NumToks = getArgLength(AT)+1; // Include the EOF.
// Otherwise, we have to pre-expand this argument, populating Result. To do
// this, we set up a fake TokenLexer to lex from the unexpanded argument
// list. With this installed, we lex expanded tokens until we hit the EOF
// token at the end of the unexp list.
PP.EnterTokenStream(AT, NumToks, false /*disable expand*/,
false /*owns tokens*/, false /*is reinject*/);
// Lex all of the macro-expanded tokens into Result.
do {
Result.push_back(Token());
Token &Tok = Result.back();
PP.Lex(Tok);
} while (Result.back().isNot(tok::eof));
// Pop the token stream off the top of the stack. We know that the internal
// pointer inside of it is to the "end" of the token stream, but the stack
// will not otherwise be popped until the next token is lexed. The problem is
// that the token may be lexed sometime after the vector of tokens itself is
// destroyed, which would be badness.
if (PP.InCachingLexMode())
PP.ExitCachingLexMode();
PP.RemoveTopOfLexerStack();
return Result;
}
/// StringifyArgument - Implement C99 6.10.3.2p2, converting a sequence of
/// tokens into the literal string token that should be produced by the C #
/// preprocessor operator. If Charify is true, then it should be turned into
/// a character literal for the Microsoft charize (#@) extension.
///
Token MacroArgs::StringifyArgument(const Token *ArgToks,
Preprocessor &PP, bool Charify,
SourceLocation ExpansionLocStart,
SourceLocation ExpansionLocEnd) {
Token Tok;
Tok.startToken();
Tok.setKind(Charify ? tok::char_constant : tok::string_literal);
const Token *ArgTokStart = ArgToks;
// Stringify all the tokens.
SmallString<128> Result;
Result += "\"";
bool isFirst = true;
for (; ArgToks->isNot(tok::eof); ++ArgToks) {
const Token &Tok = *ArgToks;
if (!isFirst && (Tok.hasLeadingSpace() || Tok.isAtStartOfLine()))
Result += ' ';
isFirst = false;
// If this is a string or character constant, escape the token as specified
// by 6.10.3.2p2.
if (tok::isStringLiteral(Tok.getKind()) || // "foo", u8R"x(foo)x"_bar, etc.
Tok.is(tok::char_constant) || // 'x'
Tok.is(tok::wide_char_constant) || // L'x'.
Tok.is(tok::utf8_char_constant) || // u8'x'.
Tok.is(tok::utf16_char_constant) || // u'x'.
Tok.is(tok::utf32_char_constant)) { // U'x'.
bool Invalid = false;
std::string TokStr = PP.getSpelling(Tok, &Invalid);
if (!Invalid) {
std::string Str = Lexer::Stringify(TokStr);
Result.append(Str.begin(), Str.end());
}
} else if (Tok.is(tok::code_completion)) {
PP.CodeCompleteNaturalLanguage();
} else {
// Otherwise, just append the token. Do some gymnastics to get the token
// in place and avoid copies where possible.
unsigned CurStrLen = Result.size();
Result.resize(CurStrLen+Tok.getLength());
const char *BufPtr = Result.data() + CurStrLen;
bool Invalid = false;
unsigned ActualTokLen = PP.getSpelling(Tok, BufPtr, &Invalid);
if (!Invalid) {
// If getSpelling returned a pointer to an already uniqued version of
// the string instead of filling in BufPtr, memcpy it onto our string.
if (ActualTokLen && BufPtr != &Result[CurStrLen])
memcpy(&Result[CurStrLen], BufPtr, ActualTokLen);
// If the token was dirty, the spelling may be shorter than the token.
if (ActualTokLen != Tok.getLength())
Result.resize(CurStrLen+ActualTokLen);
}
}
}
// If the last character of the string is a \, and if it isn't escaped, this
// is an invalid string literal, diagnose it as specified in C99.
if (Result.back() == '\\') {
// Count the number of consecutive \ characters. If even, then they are
// just escaped backslashes, otherwise it's an error.
unsigned FirstNonSlash = Result.size()-2;
// Guaranteed to find the starting " if nothing else.
while (Result[FirstNonSlash] == '\\')
--FirstNonSlash;
if ((Result.size()-1-FirstNonSlash) & 1) {
// Diagnose errors for things like: #define F(X) #X / F(\)
PP.Diag(ArgToks[-1], diag::pp_invalid_string_literal);
Result.pop_back(); // remove one of the \'s.
}
}
Result += '"';
// If this is the charify operation and the result is not a legal character
// constant, diagnose it.
if (Charify) {
// First step, turn double quotes into single quotes:
Result[0] = '\'';
Result[Result.size()-1] = '\'';
// Check for bogus character.
bool isBad = false;
if (Result.size() == 3)
isBad = Result[1] == '\''; // ''' is not legal. '\' already fixed above.
else
isBad = (Result.size() != 4 || Result[1] != '\\'); // Not '\x'
if (isBad) {
PP.Diag(ArgTokStart[0], diag::err_invalid_character_to_charify);
Result = "' '"; // Use something arbitrary, but legal.
}
}
PP.CreateString(Result, Tok,
ExpansionLocStart, ExpansionLocEnd);
return Tok;
}
