[cfe-dev] Basic source-to-source transformation with Clang

[Satya Prakash Prasad]

Thanks once again. I am really thankful to Manuel and others in group
who gave me more insight and confidence to work with CLANG.

However please note that when I used the below code to print the C++
code (input as an input param : rewritecode test.cpp):

                        Stmt *i =  cast<Stmt>(*I);
                        SourceManager &SourceMgr =
TheCompInst.getSourceManager();
                        SourceLocation ST = i->getSourceRange().getBegin();
                        const char * code = SourceMgr.getCharacterData(ST);
                        std::cout << "STMT  : " << code << "\n";

Ii prints additional line than what I want each time. Example if my
test.cpp file is like below:

int inc(int &p)
{
        p++;
        printf("%s %d",__FILE__,__LINE__);
        printf("In inc [%d]\n", p);
        return p;
}


I get output like:

STMT : p++;
        printf("In inc [%d]\n", p);
        return p;
}
......................................................

How can I print only a single line of code at a time and not its
consecutive one. I cannot tokenize it with '\n' as there are can
multiple lines for a single statement. I would also really appreciate
if I can get some reference of good books either offline / online to
refer for beginners level.

Thanks in advance.

Regards,
Prakash

On Fri, Jul 6, 2012 at 7:30 PM, Manuel Klimek <klimek at google.com> wrote:
> On Fri, Jul 6, 2012 at 2:33 PM, Satya Prakash Prasad
> <satyaprakash.prasad at gmail.com> wrote:
>>
>> Thanks for the information as provided, but I get output like below:
>>
>> (CallExpr 0x1a85c480 'int'
>>   (ImplicitCastExpr 0x1a85c468 'int (*)(const char *restrict, ...)'
>> <FunctionToPointerDecay>
>>     (DeclRefExpr 0x1a85c3e8 'int (const char *restrict, ...)' lvalue
>> Function 0x1a84e8e0 'printf' 'int (const char *restrict, ...)'))
>>   (ImplicitCastExpr 0x1a85c4b8 'const char *' <ArrayToPointerDecay>
>>     (StringLiteral 0x1a85c388 'const char [13]' lvalue "In inc [%d]\n"))
>>   (ImplicitCastExpr 0x1a85c4d0 'int' <LValueToRValue>
>>     (DeclRefExpr 0x1a85c3c0 'int' lvalue ParmVar 0x1a85c100 'p' 'int &')))
>>
>> Kindly note that my requirement is to print the C++ code itself like
>> dumpAll() method generated for above for below C++ code:
>
>
> If you want to print the C++ code that produce the AST, you'll want to get
> the SourceRange, and use SourceManager's getCharacterData() method to get
> the underlying data - that will get you the C++ code as it was written by
> the user.
>
> Cheers,
> /Manuel
>>
>>
>> p++;
>>
>> Similarly for other like:
>>
>> dumpAll()
>>
>> (CallExpr 0x1a85dec8 'int'
>>   (ImplicitCastExpr 0x1a85deb0 'int (*)(const char *restrict, ...)'
>> <FunctionToPointerDecay>
>>     (DeclRefExpr 0x1a85de88 'int (const char *restrict, ...)' lvalue
>> Function 0x1a84e8e0 'printf' 'int (const char *restrict, ...)'))
>>   (ImplicitCastExpr 0x1a85df08 'const char *' <ArrayToPointerDecay>
>>     (StringLiteral 0x1a85cdd8 'const char [19]' lvalue "y = [%d] z =
>> [%d]\n"))
>>   (ImplicitCastExpr 0x1a85df20 'int' <LValueToRValue>
>>     (DeclRefExpr 0x1a85ce18 'int' lvalue Var 0x1a85c6f0 'y' 'int'))
>>   (ImplicitCastExpr 0x1a85df38 'int' <LValueToRValue>
>>     (DeclRefExpr 0x1a85de60 'int' lvalue Var 0x1a85c760 'z' 'int')))
>>
>> While C++ Code:
>>
>> printf("y = [%d] z = [%d]\n", y , z);
>>
>> Thanks in advance.
>>
>> Regards,
>> Prakash
>>
>>
>> On Fri, Jul 6, 2012 at 4:22 PM, Manuel Klimek <klimek at google.com> wrote:
>> > On Fri, Jul 6, 2012 at 12:25 PM, Satya Prakash Prasad
>> > <satyaprakash.prasad at gmail.com> wrote:
>> >>
>> >> I made some progress with whatever support I received from this
>> >> discussion forum. Thanks to all who responded to my request. My
>> >> requirement now is to find a way I can print CLANG AST code to C++ / C
>> >> human readable statements:
>> >>
>> >>     bool VisitStmt(Stmt *s) {
>> >>         if (isa<CompoundStmt>(s)) {
>> >>                 CompoundStmt *S = cast<CompoundStmt>(s);
>> >>                 for (CompoundStmt::body_iterator  I = S->body_begin(),
>> >> E = S->body_end(); I != E; ++I)
>> >>                 {
>> >>                         Stmt *i =  cast<Stmt>(*I);
>> >>                         //How can I print the C++ / C statement which
>> >> CLANG is processing
>> >
>> >
>> > You can use i->dumpAll() if you want to see what's going on.
>> >
>> > Cheers,
>> > /Manuel
>> >
>> >>
>> >>                 }
>> >>         }
>> >>
>> >>         return true;
>> >>     }
>> >>
>> >> Regards,
>> >> Prakash
>> >>
>> >> _______________________________________________
>> >> cfe-dev mailing list
>> >> cfe-dev at cs.uiuc.edu
>> >> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
>> >
>> >
>
>