findloop.cpp

#include <clang-c/Index.h>
#include <stdio.h>
#include <stdlib.h>

struct FindState {
    bool find;
    int target_line;
    CXCursor loop;
};

CXChildVisitResult
findLoopVisitor(CXCursor cursor,
                CXCursor parent,
                CXClientData client_data)
{
    FindState *st = (FindState*)client_data;

    CXSourceRange range = clang_getCursorExtent(cursor);

    CXSourceLocation start = clang_getRangeStart(range);
    CXSourceLocation end = clang_getRangeEnd(range);
    CXFile file;
    unsigned line_start, line_end, column, offset;

    clang_getSpellingLocation(start, &file, &line_start, &column, &offset);
    clang_getSpellingLocation(end, &file, &line_end, &column, &offset);

    bool in_range = st->target_line>=line_start && st->target_line<=line_end;

    if (cursor.kind == CXCursor_ForStmt ||
        cursor.kind == CXCursor_WhileStmt)
    {
        if (in_range) {
            st->loop = cursor;
            st->find = true;
        }
    }

    if (in_range) {
        return CXChildVisit_Recurse;
    } else {
        return CXChildVisit_Continue;
    }
}

int
main(int argc, char **argv)
{
    if (argc < 3) {
        puts("usage <lineno> <clang options> <source>");
        return 1;
    }

    int line = atoi(argv[1]);
    int num_opt = argc - 3;
    const char *source = argv[argc-1];

    CXIndex clang_idx = clang_createIndex(1,1);
    CXTranslationUnit TU = clang_createTranslationUnitFromSourceFile(
        clang_idx,
        source,
        num_opt,
        argv + 2,
        0,0);

    CXFile file = clang_getFile(TU, source);
    CXSourceLocation loc = clang_getLocation(TU, file, 1, 1);
    CXCursor cursor = clang_getCursor(TU, loc);

    FindState st;
    st.find = false;
    st.target_line = line;
    clang_visitChildren(cursor, findLoopVisitor, &st);

    if (st.find) {
        CXSourceRange range = clang_getCursorExtent(st.loop);
        CXSourceLocation start = clang_getRangeStart(range);
        CXSourceLocation end = clang_getRangeEnd(range);
        CXFile file;
        unsigned line_start, line_end, column, offset;

        clang_getSpellingLocation(start, &file, &line_start, &column, &offset);
        clang_getSpellingLocation(end, &file, &line_end, &column, &offset);

        CXString str = clang_getCursorKindSpelling(st.loop.kind);
        printf("%s: %d-%d\n", clang_getCString(str), line_start, line_end);
        clang_disposeString(str);
    }

    clang_disposeTranslationUnit(TU);
    clang_disposeIndex(clang_idx);
}