llvm dev - Aug 2021 - [cfe-dev] Location (in Source Code) of String Literal in MacroExpansion

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)?
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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

 

From: cfe-dev <cfe-dev-bounces at lists.llvm.org> On Behalf Of chiasa.men
via cfe-dev
Sent: 2021. augusztus 26., csütörtök 10:03
To: cfe-dev <cfe-dev at lists.llvm.org>
Cc: llvm-dev at lists.llvm.org
Subject: [cfe-dev] Location (in Source Code) of String Literal in MacroExpansion

 

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)?

 

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