Next patch, next try …
The problem is the following: We have a use-associated symbol (a
function) – which is once referenced (by use association).
We now declare a same-name function in the 'contains' section.
gfortran now parses the function name, fetches the symbol and reports
that one duplicates the function (gfc_error_now). However, it continues
afterwards and creates a sym_tree in the gfc_current_ns – and duly
increases the sym->refs to 2.
A bit later, the function gets rejected. (Parsing of the formal
arguments fails when setting a attribute of a use-associated symbol, but
I think this doesn't matter. reject_statement() is called, which rolls
back the symbol, but again, I think that doesn't matter – it just makes
some other solutions a tad more difficult.)
Now, the contains namespace is cleaned up: As the function name is in
the namespace's sym_tree, gfc_release_symbol() is invoked.
The symbol itself is not freed (as --refs > 0), but sym->formal_ns is.
(There are some safety nets, like sym->rev == 2 and sym->ns !=
sym->formal_ns, but they don't help.)
Later, the symbol of the parent's namespace is resolved – and this
includes resolving the formal arguments. – And accessing freed memory
might crash gfortran.
As solution, I return early and with an error from get_proc_name(). I
think that's cleaner than waiting longer – and the early return avoids
creating the symbol at the first place. (Otherwise, modifications have
to go beyond rolling back of the symbols; doing refs++ probably helps,
but is rather intransparent.)
Pro of the early return: Avoids accessing already freed memory, might
generate shorter error output as some later fails (like for not being
able to modify attributes of a use-associated symbol) are gone.
Contra: As one returns before entering a procedure, all following lines
are in the outer scope (usually 'contains') and there probably
unexpected. Hence, one might get a bunch of follow-up errors which do
not help.
Build on x86-64 and even more carefully regtested.
OK?
Tobias
2018-10-12 Tobias Burnus
PR fortran/58787
* decl.c (get_proc_name): Return with error before
creating sym_tree.
PR fortran/58787
* gfortran.dg/goacc/pr77765.f90: Modify dg-error.
* gfortran.dg/interface_42.f90: Ditto.
* gfortran.dg/internal_references_1.f90: Ditto.
* gfortran.dg/invalid_procedure_name.f90: Ditto.
* gfortran.dg/pr65453.f90: Ditto.
* gfortran.dg/pr77414.f90: Ditto.
* gfortran.dg/pr78741.f90: Ditto.
* gfortran.dg/same_name_2.f90: Ditto.
diff --git a/gcc/fortran/decl.c b/gcc/fortran/decl.c
index 7f79811d152..87c736fb2db 100644
--- a/gcc/fortran/decl.c
+++ b/gcc/fortran/decl.c
@@ -1231,28 +1231,39 @@ get_proc_name (const char *name, gfc_symbol **result, bool module_fcn_entry)
&& sym->attr.proc != 0
&& (sym->attr.subroutine || sym->attr.function || sym->attr.entry)
&& sym->attr.if_source != IFSRC_UNKNOWN)
- gfc_error_now ("Procedure %qs at %C is already defined at %L",
- name, >declared_at);
-
+ {
+ gfc_error_now ("Procedure %qs at %C is already defined at %L",
+ name, >declared_at);
+ return true;
+ }
if (sym->attr.flavor != 0
&& sym->attr.entry && sym->attr.if_source != IFSRC_UNKNOWN)
- gfc_error_now ("Procedure %qs at %C is already defined at %L",
- name, >declared_at);
+ {
+ gfc_error_now ("Procedure %qs at %C is already defined at %L",
+ name, >declared_at);
+ return true;
+ }
if (sym->attr.external && sym->attr.procedure
&& gfc_current_state () == COMP_CONTAINS)
- gfc_error_now ("Contained procedure %qs at %C clashes with "
- "procedure defined at %L",
- name, >declared_at);
+ {
+ gfc_error_now ("Contained procedure %qs at %C clashes with "
+ "procedure defined at %L",
+ name, >declared_at);
+ return true;
+ }
/* Trap a procedure with a name the same as interface in the
encompassing scope. */
if (sym->attr.generic != 0
&& (sym->attr.subroutine || sym->attr.function)
&& !sym->attr.mod_proc)
- gfc_error_now ("Name %qs at %C is already defined"
- " as a generic interface at %L",
- name, >declared_at);
+ {
+ gfc_error_now ("Name %qs at %C is already defined"
+ " as a generic interface at %L",
+ name, >declared_at);
+ return true;
+ }
/* Trap declarations of attributes in encompassing scope. The
signature for this is that ts.kind is set. Legitimate
@@ -1263,8 +1274,11 @@ get_proc_name (const char *name, gfc_symbol **result, bool module_fcn_entry)
&& gfc_current_ns->parent != NULL
&& sym->attr.access == 0
&& !module_fcn_entry)
- gfc_error_now ("Procedure %qs at %C has an explicit interface "
+ {
+ gfc_error_now ("Procedure %qs at %C has an explicit interface "
"from a previous declaration", name);
+ return true;
+ }
}
/* C1246 (R1225) MODULE shall appear only in the function-stmt or
@@ -1276,17 +1290,23 @@ get_proc_name (const char *name, gfc_symbol
