| Message ID | 20180323104802.GM3522@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | C++ PATCH for c++/85033, ICE with enumerator in __builtin_offsetof | expand |
OK. On Fri, Mar 23, 2018 at 6:48 AM, Marek Polacek <polacek@redhat.com> wrote: > In this test: > > struct S { > enum { X }; > }; > > int > foo (struct S s) > { > return s.X; > } > > unlike in C, lookup_member in C++ is able to find X in S. So in the following > testcase finish_offsetof happily passes the CONST_DECL X down to fold_offsetof, > which then crashes because fold_offsetof_1 doesn't handle CONST_DECLs. I think > let's simply disallow 'em in finish_offsetof; we can't take their address anyway. > > Bootstrapped/regtested on x86_64-linux, ok for trunk? > > 2018-03-23 Marek Polacek <polacek@redhat.com> > > PR c++/85033 > * semantics.c (finish_offsetof): Don't allow CONST_DECLs. > > * g++.dg/ext/builtin-offsetof2.C: New test. > > diff --git gcc/cp/semantics.c gcc/cp/semantics.c > index 97fa57ae94e..035e3951574 100644 > --- gcc/cp/semantics.c > +++ gcc/cp/semantics.c > @@ -4072,6 +4072,11 @@ finish_offsetof (tree object_ptr, tree expr, location_t loc) > } > return error_mark_node; > } > + if (TREE_CODE (expr) == CONST_DECL) > + { > + error ("cannot apply %<offsetof%> to an enumerator %qD", expr); > + return error_mark_node; > + } > if (REFERENCE_REF_P (expr)) > expr = TREE_OPERAND (expr, 0); > if (!complete_type_or_else (TREE_TYPE (TREE_TYPE (object_ptr)), object_ptr)) > diff --git gcc/testsuite/g++.dg/ext/builtin-offsetof2.C gcc/testsuite/g++.dg/ext/builtin-offsetof2.C > index e69de29bb2d..07cc55a65c1 100644 > --- gcc/testsuite/g++.dg/ext/builtin-offsetof2.C > +++ gcc/testsuite/g++.dg/ext/builtin-offsetof2.C > @@ -0,0 +1,7 @@ > +// PR c++/85033 > + > +struct S { > + enum { E }; > +}; > + > +int b = __builtin_offsetof(S, E); // { dg-error "cannot apply .offsetof. to an enumerator" } > > Marek
diff --git gcc/cp/semantics.c gcc/cp/semantics.c index 97fa57ae94e..035e3951574 100644 --- gcc/cp/semantics.c +++ gcc/cp/semantics.c @@ -4072,6 +4072,11 @@ finish_offsetof (tree object_ptr, tree expr, location_t loc) } return error_mark_node; } + if (TREE_CODE (expr) == CONST_DECL) + { + error ("cannot apply %<offsetof%> to an enumerator %qD", expr); + return error_mark_node; + } if (REFERENCE_REF_P (expr)) expr = TREE_OPERAND (expr, 0); if (!complete_type_or_else (TREE_TYPE (TREE_TYPE (object_ptr)), object_ptr)) diff --git gcc/testsuite/g++.dg/ext/builtin-offsetof2.C gcc/testsuite/g++.dg/ext/builtin-offsetof2.C index e69de29bb2d..07cc55a65c1 100644 --- gcc/testsuite/g++.dg/ext/builtin-offsetof2.C +++ gcc/testsuite/g++.dg/ext/builtin-offsetof2.C @@ -0,0 +1,7 @@ +// PR c++/85033 + +struct S { + enum { E }; +}; + +int b = __builtin_offsetof(S, E); // { dg-error "cannot apply .offsetof. to an enumerator" }
In this test: struct S { enum { X }; }; int foo (struct S s) { return s.X; } unlike in C, lookup_member in C++ is able to find X in S. So in the following testcase finish_offsetof happily passes the CONST_DECL X down to fold_offsetof, which then crashes because fold_offsetof_1 doesn't handle CONST_DECLs. I think let's simply disallow 'em in finish_offsetof; we can't take their address anyway. Bootstrapped/regtested on x86_64-linux, ok for trunk? 2018-03-23 Marek Polacek <polacek@redhat.com> PR c++/85033 * semantics.c (finish_offsetof): Don't allow CONST_DECLs. * g++.dg/ext/builtin-offsetof2.C: New test. Marek