[cfe-commits] Patch for review: enhancements/fixes to -verify

[Andy Gibbs]

Hi all,

The -verify option has the potential for uses outside just the clang 
test-suite, for example, within a test-suite for a 3rd-party library. 
However, it has a number of idiosyncrasies or missing features which the 
attached patch seeks to address.  While none of the alterations are perhaps 
critical to the development of clang itself (that remains to be seen!), they 
do make the -verify feature immeasurably more flexible and useful.

In the first instance, the patch enables -verify to distinguish between 
blocks of code which have been #if/#ifdef-ed out and those which have not. 
The current implementation will not do this, so for example, this trivial 
fragment will cause an "expected but not seen" failure:

#if 0
#error some error // expected-error {{some error}}
#endif

Secondly, in the current implementation, all diagnostics must be contained 
on the actual line which generates the diagnostic.  The new implementation 
allows a line number to be optionally specified as part of the diagnostic 
declaration using the @ symbol, for example:

// expected-error@<line> {{some error}}

where <line> can be some absolute line number, for example: 10, or a 
relative line number, for example: -1 or +5, from the current line.  Note 
that where an absolute line number is given this is intentionally the actual 
source line in the file in question, not one modified by the #line 
directive.  Likewise, relative line numbers are also not affected by the 
#line directive.

Thirdly, in the current implementation, it is possible to specify an exact 
number of times a diagnostic will appear, or that it will appear "1 or more" 
times.  This new implementation extends this to enable the test case to 
specify a more precise range.  Therefore, the following are now possible:

(Those marked * are already possible in the current implementation)

// expected-error 2 {{some error}} -- must appear twice*
// expected-error + {{some error}} -- must appear once at least*
// expected-error 1+ {{some error}} -- same as the line above
// expected-error 0+ {{some error}} -- may or may not appear
// expected-error 2-5 {{some error}} -- must appear at least 2 but not more 
than 5 times.

The patch also includes the relevant modifications necessary to the existing 
clang test-suite.  These modifications were necessary for two reasons: since 
#if-block processing is now included, various tests in the PCH folder were 
now missing their relevant diagnostics.  Also #error/#warning directives 
include all text up to the end-of-line in their message so tests containing 
these have the diagnostics shifted onto a separate line now.

Coincidentally, this is a good thing in any case since (as was highlighted 
in Preprocessor/line-directive.c) the following line will always 
(erroneously!) pass in the current implementation:

#error AAA // expected-error {{BBB}}

A couple of tests have also been added to test the new features of -verify.

The attached patch is taken against the current trunk.  I hope it meets the 
quality criteria to be considered for committal.  Please don't hesitate to 
quiz me on any aspect of it!

Kind regards

Andy



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