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Oh, now I see why you were puzzled!

\`printf()\` expects a null-terminated string (“%s”), but you pass an llvm::StringRef instead, which is not null terminated!

Thus, you will end up with undefined behavior, which ends up printing till the end of the file.

I hope this is it!

Balazs

Hi Chiasa,

For the example you attached the MacroExpansionContext seems to work as I intended.

It records what range gets replaced by what tokens at the end of the preprocessing, thus we get

\`CONCATMACRO("TEST")\` -> \` L"TEST"\`

About \`Lexer::getSourceText()\` I’m not sure. I haven’t used that. The \`at()\` function was designed as a helper defining the unit tests. I might misused something when I created this code & tests, let me know!

Balazs

https://gist.github.com/T35R6braPwgDJKq/6439fda090e4ee8440d726f8dafa4dbb#file-mectest-cpp

Above I modified the MacroExpansionContext unittest.

The relevant code:

//--------------

TEST\_F(MacroExpansionContextTest, Custom) {

// From the GCC website.

const auto Ctx = getMacroExpansionContextFor(R"code(

#define CONCATMACRO(parm) L##parm

int f(wchar\_t \*b){}

int main()

{

int a= f(CONCATMACRO("TEST"));

int b= f(L"TEST");

return 0;

}

)code");

Ctx->dumpExpansionRanges();

//> :6:14, :6:33

Ctx->dumpExpandedTexts();

//> :6:14 -> 'L"TEST"'

printf("Exp: %s\\n",Ctx->getExpandedText(at(6, 14)).getValue());

//Exp: L"TEST"

printf("Org: %s\\n",Ctx->getOriginalText(at(6, 14)).getValue());

//Org: CONCATMACRO("TEST"));

// int b= f(L"TEST");

// return 0;

//}

StringRef sourceText = clang::Lexer::getSourceText(CharSourceRange(SourceRange(at(6, 14),at(6, 33)),false),SourceMgr, LangOpts);

printf("sourceText: %s\\n",sourceText);

// sourceText: CONCATMACRO("TEST"));

// int b= f(L"TEST");

// return 0;

// }

}

//--------------

I am interested in getting the range for "TEST" in the SourceText. Since the CONCATMACRO is preprocessed to L"TEST" I thought the MacroExpansionContext would be of help.

It tells about the ExpansionRanges: 6:14, :6:33 which is CONCATMACRO("TEST")

What I would need is: 6:26, 6:32

Obviously I could just calculate a bit like:

range.begin (14) + macronameLen (11) +1 (opening parenthesis) = 26

to

range.end (33) - 1 (closing parenthesis) = 32

But would that be reliable and is there no other way?

Furthermore: Why do getSourceText/getOriginalText print the whole rest of the source code and not just from (6,14) to (6,33)?