On 09/20/2017 12:04 PM, Martin Sebor wrote: > On 09/19/2017 03:00 PM, Joseph Myers wrote: >> On Tue, 19 Sep 2017, Martin Sebor wrote: >> >>>> In general, the data structures where you need to ensure manually that if >>>> >>>> attribute A is listed in EXCL for B, then attribute B is also listed in >>>> EXCL for A, seem concerning. I'd expect either data structures that make >>>> >>>> such asymmetry impossible, or a self-test that verifies that the tables in >>>> >>>> use are in fact symmetric (unless there is some reason the symmetry is not >>>> >>>> in fact required and symmetric diagnostics still result from asymmetric >>>> tables - in which case the various combinations and orderings of >>>> gnu_inline and noinline definitely need tests to show that the diagnostics >>>> >>>> work). >>> >>> If I understand correctly what you're concerned about then I don't >>> think there are any such cases in the updated version of the patch. >> >> I don't see how you ensure that it's not possible to have such asymmetry. >> My point wasn't so much "there was a bug in the previous patch version" as >> >> "the choice of data structures for defining such exclusions is prone to >> such bugs". Which can be addressed either by using different data >> structures (e.g. listing incompatible pairs in a single array) or by a >> self-test to verify symmetry so a compiler with asymmetry doesn't build. > > Okay, that's a useful thing to add. It exposed a couple of missing > attribute exclusions that I had overlooked. Thanks for the suggestion! > Attached is an incremental diff with just these changes to make review > easier and an updated patch. > > As an aside, there are a number of other possible logic errors in > the attribute specifications that could be detected by self-tests. > The one I ran into is misspelled attribute names. The added test > detects misspelled names in exclusions, but not in the main specs. > > Martin > > gcc-81544-1-inc.diff > >
> gcc-81544-1.diff > > > PR c/81544 - attribute noreturn and warn_unused_result on the same function > accepted > > gcc/c/ChangeLog: > > PR c/81544 > * c-decl.c (c_decl_attributes): Look up existing declaration and > pass it to decl_attributes. > > gcc/c-family/ChangeLog: > > PR c/81544 > * c-attribs.c (attr_aligned_exclusions): New array. > (attr_alloc_exclusions, attr_cold_hot_exclusions): Same. > (attr_common_exclusions, attr_const_pure_exclusions): Same. > (attr_gnu_inline_exclusions, attr_inline_exclusions): Same. > (attr_noreturn_exclusions, attr_returns_twice_exclusions): Same. > (attr_warn_unused_result_exclusions): Same. > (handle_hot_attribute, handle_cold_attribute): Simplify. > (handle_const_attribute): Warn on function returning void. > (handle_pure_attribute): Same. > * c-warn.c (diagnose_mismatched_attributes): Simplify. > > gcc/ChangeLog: > > PR c/81544 > * attribs.c (empty_attribute_table): Initialize new member of > struct attribute_spec. > (decl_attributes): Add argument. Handle mutually exclusive > combinations of attributes. > * attribs.h (decl_attributes): Add default argument. > * selftest.h (attribute_c_tests): Declare. > * selftest-run-tests.c (selftest::run_tests): Call attribute_c_tests. > * tree-core.h (attribute_spec::exclusions, exclude): New type and > member. > * doc/extend.texi (Common Function Attributes): Update const and pure. > > gcc/testsuite/ChangeLog: > > PR c/81544 > * c-c++-common/Wattributes-2.c: New test. > * c-c++-common/Wattributes.c: New test. > * c-c++-common/attributes-3.c: Adjust. > * gcc.dg/attr-noinline.c: Adjust. > * gcc.dg/pr44964.c: Same. > * gcc.dg/torture/pr42363.c: Same. > * gcc.dg/tree-ssa/ssa-ccp-2.c: Same. OK. jeff
