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Fix #653: defined() not recognizing ## token paste in its operand (GNU extension) #694

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Fix #653: defined() not recognizing ## token paste in its operand (GNU extension) #694

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208326f
add test
ludviggunne Aug 5, 2026
ce06610
fix
ludviggunne Aug 5, 2026
e56a09a
fixes
ludviggunne Aug 5, 2026
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53 changes: 29 additions & 24 deletions simplecpp.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2249,33 +2249,38 @@ namespace simplecpp {
}

if (tok->str() == DEFINED) {
const Token * const tok2 = tok->next;
const Token * const tok3 = tok2 ? tok2->next : nullptr;
const Token * const tok4 = tok3 ? tok3->next : nullptr;
const Token *defToken = nullptr;
const Token *lastToken = nullptr;
if (sameline(tok, tok4) && tok2->op == '(' && tok3->name && tok4->op == ')') {
defToken = tok3;
lastToken = tok4;
} else if (sameline(tok,tok2) && tok2->name) {
defToken = lastToken = tok2;
std::string macroName;
TokenList temp(files);
const Token *argTok = tok->next;
bool expectParen = false;
if (argTok->op == '(') {

@danmar danmar Sep 1, 2026

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we used to prevent null pointer dereference when tok->next is null

@danmar danmar Sep 1, 2026

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it seems that sameline is not used properly anymore.

argTok = argTok->next;
expectParen = true;
}
if (defToken) {
std::string macroName = defToken->str();
if (defToken->next && defToken->next->op == '#' && defToken->next->next && defToken->next->next->op == '#' && defToken->next->next->next && defToken->next->next->next->name && sameline(defToken,defToken->next->next->next)) {
TokenList temp(files);
if (expandArg(temp, defToken, parametertokens))
macroName = temp.cback()->str();
if (expandArg(temp, defToken->next->next->next, parametertokens))
macroName += temp.cback() ? temp.cback()->str() : "";
else
macroName += defToken->next->next->next->str();
lastToken = defToken->next->next->next;
while (argTok->name) {
if (expandArg(temp, argTok, parametertokens))

@danmar danmar Aug 5, 2026

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I am not sure that we should expand macros unless they are operands. will this work:

#define x
#if defined(x)

the macroName will be empty string here now? and we will think that the condition is false?

@ludviggunne ludviggunne Aug 6, 2026

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It works, it takes a different execution path.

macroName += temp.cback() ? temp.cback()->str() : "";
else
macroName += argTok->str();
argTok = argTok->next;
if (!sameline(tok, argTok))
break;
if (argTok && argTok->str() == "#") {
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if (!argTok->next || argTok->next->str() != "#")
throw Error(argTok->location, "Expected '#'");
argTok = argTok->next->next;
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} else {
break;
}
const bool def = (macros.find(macroName) != macros.end());
output.push_back(newMacroToken(def ? "1" : "0", loc, true));
return lastToken->next;
}
if (expectParen) {
if (!sameline(tok, argTok) && argTok->op != ')')
throw Error(argTok->location, "Expected ')'");
argTok = argTok->next;
}
const bool def = (macros.find(macroName) != macros.end());
output.push_back(newMacroToken(def ? "1" : "0", loc, true));
return argTok;
}

output.push_back(newMacroToken(tok->str(), loc, true, tok));
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12 changes: 12 additions & 0 deletions test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2388,6 +2388,17 @@ static void ifDefinedHashHash2()
ASSERT_EQUALS("\n0", preprocess(code, &outputList));
}

static void ifDefinedHashHash3()
{
const char code[] = "#define ENABLED(x) (defined(x ## _ENABLED) && (x ## _ENABLED))\n"
"#define FOO_ENABLED 1\n"
"#if ENABLED(FOO)\n"
"int x;\n"
"#endif\n";
simplecpp::OutputList outputList;
ASSERT_EQUALS("\n\n\nint x ;", preprocess(code, &outputList));
}

static void ifLogical()
{
const char code[] = "#if defined(A) || defined(B)\n"
Expand Down Expand Up @@ -4701,6 +4712,7 @@ static void runTests(int argc, char **argv, Input input)
TEST_CASE(ifDefinedInvalid2);
TEST_CASE(ifDefinedHashHash);
TEST_CASE(ifDefinedHashHash2);
TEST_CASE(ifDefinedHashHash3);
TEST_CASE(ifLogical);
TEST_CASE(ifSizeof);
TEST_CASE(elif);
Expand Down
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