On Sep 17, 2012, at 2:38 PM, James Dennett <[email protected]> wrote:

> On Mon, Sep 17, 2012 at 2:22 PM, Argyrios Kyrtzidis <[email protected]> 
> wrote:
>> On Sep 17, 2012, at 12:44 PM, James Dennett <[email protected]> wrote:
>> 
>>> On Mon, Sep 10, 2012 at 7:17 PM, Argyrios Kyrtzidis <[email protected]> 
>>> wrote:
>>>> Author: akirtzidis
>>>> Date: Mon Sep 10 21:17:21 2012
>>>> New Revision: 163588
>>>> 
>>>> URL: http://llvm.org/viewvc/llvm-project?rev=163588&view=rev
>>>> Log:
>>>> [libclang] Fix getting a cursor inside an angled #include directive.
>>>> 
>>>> Fixed by pointing the end location of the preprocessed entity for the 
>>>> #include
>>>> at the closing '>', instead of the start of '<'.
>>>> 
>>>> rdar://11113134
>>>> 
>>>> Modified:
>>>>   cfe/trunk/lib/Lex/PPDirectives.cpp
>>>>   cfe/trunk/test/Index/c-index-getCursor-pp.c
>>>> 
>>>> Modified: cfe/trunk/lib/Lex/PPDirectives.cpp
>>>> URL: 
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Lex/PPDirectives.cpp?rev=163588&r1=163587&r2=163588&view=diff
>>>> ==============================================================================
>>>> --- cfe/trunk/lib/Lex/PPDirectives.cpp (original)
>>>> +++ cfe/trunk/lib/Lex/PPDirectives.cpp Mon Sep 10 21:17:21 2012
>>>> @@ -1296,6 +1296,9 @@
>>>>  case tok::string_literal:
>>>>    Filename = getSpelling(FilenameTok, FilenameBuffer);
>>>>    End = FilenameTok.getLocation();
>>>> +    // For an angled include, point the end location at the closing '>'.
>>>> +    if (FilenameTok.is(tok::angle_string_literal))
>>>> +      End = End.getLocWithOffset(Filename.size()-1);
>>>>    CharEnd = End.getLocWithOffset(Filename.size());
>>>>    break;
>>>> 
>>>> 
>>>> Modified: cfe/trunk/test/Index/c-index-getCursor-pp.c
>>>> URL: 
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Index/c-index-getCursor-pp.c?rev=163588&r1=163587&r2=163588&view=diff
>>>> ==============================================================================
>>>> --- cfe/trunk/test/Index/c-index-getCursor-pp.c (original)
>>>> +++ cfe/trunk/test/Index/c-index-getCursor-pp.c Mon Sep 10 21:17:21 2012
>>>> @@ -15,6 +15,8 @@
>>>> 
>>>> const char *fname = __FILE__;
>>>> 
>>>> +#include <a.h>
>>>> +
>>>> // RUN: c-index-test -cursor-at=%s:1:11 -I%S/Inputs %s | FileCheck 
>>>> -check-prefix=CHECK-1 %s
>>>> // CHECK-1: macro definition=OBSCURE
>>>> // RUN: c-index-test -cursor-at=%s:2:14 -I%S/Inputs %s | FileCheck 
>>>> -check-prefix=CHECK-2 %s
>>>> @@ -31,6 +33,8 @@
>>>> // CHECK-7: macro expansion=B:12:9
>>>> // RUN: c-index-test -cursor-at=%s:16:25 -I%S/Inputs %s | FileCheck 
>>>> -check-prefix=CHECK-8 %s
>>>> // CHECK-8: macro expansion=__FILE__
>>>> +// RUN: c-index-test -cursor-at=%s:18:12 -I%S/Inputs %s | FileCheck 
>>>> -check-prefix=CHECK-9 %s
>>>> +// CHECK-9: inclusion directive=a.h
>>>> 
>>>> // Same tests, but with "editing" optimizations
>>>> // RUN: env CINDEXTEST_EDITING=1 c-index-test -cursor-at=%s:1:11 
>>>> -I%S/Inputs %s | FileCheck -check-prefix=CHECK-1 %s
>>> 
>>> This change broke clients that implement
>>> PPCallbacks::InclusionDirective, which now receive the location of the
>>> closing '>' rather than the location of the token that they're
>>> expecting based on the spec:
>>> /// \param EndLoc The location of the last token within the
>>> inclusion
>>> /// directive.
>>> The last (preprocessing) token is the whole of <filename>, of type
>>> tok::angle_string_literal.
>>> 
>>> Could we consider reverting this change and finding an alternative way
>>> to fix libclang without breaking/changing the lower-level interface?
>> 
>> Hi James,
>> 
>> This is not a high-level libclang issue.
> 
> Apologies, I was going by the change description "[libclang] Fix
> getting a cursor inside an angled #include directive.", and that the
> only tests I saw included were for libclang.  (That does suggests that
> we're missing tests for this in the appropriate place.)

You're right, a preprocessing record unit test is also needed.

> 
>> The preprocessing record needs to know the '>' location and depends on the 
>> PPCallbacks::InclusionDirective callback. Previously this callback did not 
>> provide a way to reliably get at that location.
> 
> I'm not sure about that -- it provided a way to get there, but it was
> necessary to skip over the filename.

If the include filename was formed via a macro expansion then you had an EndLoc 
pointing at '>'. So this was the situation:

No macro expansions involved: EndLoc points at '<'
With macro expansion: EndLoc points at '>'.

The receiver had no easy way to know which case it was. With the change it 
always pointed at '>'.

> With your change a similar trick
> is required for code wanting to get to the filename, but only for
> #include <filename>, not for #include "filename".  (Why are the two
> cases different?  Currently the callback returns the location of the
> opening quote for the #include "name" case, and the closing one for
> #include <name>.  The asymmetry seems strange.)

There's an asymmetry due to how lexing would behave if you pointed at the 
beginning of the filename, for example:

#include "filename"
If you point at the opening quote and start lexing you will get the 
tok::string_literal token, the same that the preprocessor saw. Then you can get 
at the character range of the whole filename input by checking the token size.

#include <filename>
if you point at the opening '<' and start lexing you will get a tok::less 
token, you need to get into the special "parsing include directive" mode to 
receive a tok::angle_string_literal token.
So just pointing at '<' will not allow you to easily lex and get the character 
range of the filename input.

> 
>> I believe we still need to modify the bahavior of the InclusionDirective 
>> callback and focus the discussion there.
>> 
>> How about reverting the EndLoc adjustment but have the InclusionDirective 
>> also pass the FilenameTok token so that receivers of the callback can have 
>> more information for the inclusion directive (then the preprocessing record 
>> can do the adjustment itself).
> 
> That sounds good to me -- though I'm not sure if we need to pass
> EndLoc if we pass the FilenameTok (possibly for cases where the
> filename comes from macro expansion? I'm not all that familiar with
> this code).

Yes, the EndLoc is necessary because if there are macro expansions involved 
then the FilenameTok token will be a tok::less for '<'.

> I believe that passing the FilenameTo to
> InclusionDirective() would make life easier for consumers.  Leaving
> EndLoc there is the easy option, but I'm not sure if that's just
> leaving detritus behind.
> 
> -- James

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