[cfe-dev] Get full source of multiple macro definitions using libtooling

[John Bartelme via cfe-dev]

On Mon, May 9, 2016 at 5:35 AM, Manuel Klimek <klimek at google.com> wrote:

> On Fri, May 6, 2016 at 9:04 PM John Bartelme via cfe-dev <
> cfe-dev at lists.llvm.org> wrote:
>
>> Hopefully this is an acceptable list to ask a question about libtooling
>> on:
>>
>> Ultimately I'm trying to pull out relevant structures from thousands of
>> existing c and c++ header files. I've been able to use libtooling to pull
>> out a structure and all of the structures/enums/typedefs etc it relies on
>> from various different headers. Unfortunately when I get the source range
>> backing the Decls it still references the macros defined there in. I'm
>> currently trying to find a way to access and print the source of these
>> macros but not having much luck when multiple macros are defined.
>>
>> For example:
>>
>> #define INT int
>> #define UNSIGNED unsigned
>> #define NAME name
>>
>> typedef struct {
>>    UNSIGNED long INT NAME;
>> } test;
>>
>> When I get the FieldDecl corresponding to name and get the SourceRange I
>> see the spelling location pointing to "#define UNSIGNED unsigned".
>>
>
> With that you probably mean the spelling location of the start location? A
> SourceRange doesn't have a spelling *location* :)
>

That's correct.  I do mean the start location of the range. Sorry for being
confusing here.  I guess my first question is if given a range I can get to
all SourceLocations that contain a macro with associated spelling location
or if I need to go back to the Decl to get the next range/sourcelocation

>
>
>> I'd like to know how to get to the other macro definition's source
>> locations. I know that when I change "UNSIGNED long INT NAME;" to "unsigned
>> long INT NAME;" the spelling location will then point to "#define INT int".
>>
>
> Again, I'm not sure which location you're using.
>
>
>> It seems as if declaration names are treated differently though as
>> changing to "unsigned long int NAME;" leaves me with no spelling location.
>>
>> Is there a way to get multiple spelling locations given a SourceRange? Do
>> I need to narrow down the source range some other way? I've tried lexing to
>> the next token but the doesn't leave me with a new spelling location. I'm
>> also going to have to account for macros in arrays such as "int
>> bob[MAX_WIDTH][MAX_HEIGHT]" but I'm hoping once I figure out my issues here
>> that will become clear. Thanks in advance for any help that can be
>> provided.  john
>>
>
> All the info is in the SourceRange / SourceLocation; SourceLocation
> actually provides all relevant instantiation points.
> It depends on:
> - which source location you're querying against; if you have the Decl,
> like FieldDecl, generally getLocation() will get you the name (that is, the
> spelling loc will point at 'name' and the expansion locs will point at the
> #define NAME and the NAME; respectively).
> - whether you really want a  range; for ranges, there's
> Lexer::makeFileCharRange and Lexer::getSourceText for that
>

Is there an easy way to iterate through the all the source locations that
would contain macro expansions? I've had good luck with nested macros by
tracing the immediate expansion locations from the original spelling
location but no luck in trying to get to another SourceLocation that has
different spelling location than the first macro in the statement.  I
thought perhaps I needed to try and walk through the different
QualType/Type classes associated with the field but then I wasn't sure how
to peel those back so I got every macro expansion and then also how to get
those back to their SourceLocations.  To summarize given a generic
statement like the one above "UNSIGNED long INT NAME;" I want to be able to
pull out the, in this case 3, SourceLocations that are associated with the
appropriate spelling locations.  Thanks so much, john
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