[PATCH] D30854: [ASTMatchers] Add ObjC matchers for fundamental decls

Aaron Ballman via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Tue Mar 14 10:26:22 PDT 2017

aaron.ballman added inline comments.

Comment at: unittests/ASTMatchers/ASTMatchersNodeTest.cpp:1547
+  std::string ObjCString =
+    "#pragma clang diagnostic ignored \"-Wobjc-root-class\"\n"
+    "@protocol Proto "
kastiglione wrote:
> aaron.ballman wrote:
> > kastiglione wrote:
> > > kastiglione wrote:
> > > > aaron.ballman wrote:
> > > > > Instead of using a pragma for this, I think it would make more sense to just modify `matchesObjC()` to disable the diagnostic. This is only intended to test the dynamic AST matchers, so the diagnostics are not useful in that case anyway.
> > > > `matchesConditionally()` accepts only one compiler arg, so putting the diagnostics here was a smaller change than refactoring that function. Do you think it would be better to refactor `matchesConditionally()`?
> > > I notice that many other tests have warnings. Should these tests just allow the warnings to be emitted?
> > We generally let the warnings go -- it's not harmful to have them. However, if this is a warning that's likely to trigger on most tests, there's no harm in suppressing it either.
> Sounds good, I'm for suppressing them. Should I refactor `matchesConditionally()` to allow multiple compile args, and disable these warnings from `matchesObjC()`?
Yes, I think that's the way to go.

Comment at: unittests/ASTMatchers/ASTMatchersTest.h:123
     Code, AMatcher, true,
-    "", FileContentMappings(), "input.m");
+    "-fobjc-runtime=macosx", FileContentMappings(), "input.m");
kastiglione wrote:
> aaron.ballman wrote:
> > kastiglione wrote:
> > > aaron.ballman wrote:
> > > > Can you explain why this change is required?
> > > `Code` was not being evaluated as Objective-C 2, which resulted in warnings and errors for the test this diff introduces. Setting the runtime was the first approach I tried, and it worked so I went with it without looking into why it was necessary. Now that you've asked, I stepped through and found that the `i386-unknown-unknown` triple is resulting in the use of an ELF toolchain and GCC objc runtime.
> > > 
> > > It can be changed to `-fobjc-nonfragile-abi`, which seems better than a specific runtime, do you agree? Is there any reason to not have Objective-C 2 be the default?
> > I think -fobjc-nonfragile-abi may be fine, but I guess I'm surprised that ObjC1 didn't require any specific runtime and ObjC2 requires one or else you get errors (warnings are fine, however -- we have plenty of those in these tests).
> > 
> > Perhaps it's time to fix the FIXME in `matchesConditionally()` so that we don't need to specify the triple at all, and then you won't need to specify the runtime? I don't think that should hold up this patch, however.
> > I'm surprised that ObjC1 didn't require any specific runtime and ObjC2 requires one or else you get errors
> I think this is because the existing ObjC in this test was small in size and coverage of syntax/features. Given the variable name `Objc1String`, it was probably written to avoid ObjC2 specific abi/features.
Fair enough


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