diff mbox series

[Fortran] PR 92208 don't use function-result dummy variable as actual argument

Message ID 009d3b27-2b32-5ee7-3438-3c29ae2594e7@codesourcery.com
State New
Headers show
Series [Fortran] PR 92208 don't use function-result dummy variable as actual argument | expand

Commit Message

Tobias Burnus Oct. 29, 2019, 9:09 a.m. UTC 
For code like:
    call foo(char_array=bar())
gfortran was using the symbol of the (hidden) result-string-length dummy 
argument of "bar" ("..__result") as (hidden) string-length actual 
argument when calling "foo".

Naturally, the middle end was not amused and gave an ICE (with GCC 9 + 10).

For the attached test case (cf. also PR), the LHS (se->string_length) 
already contained the expected string length (MAX_EXPR 
<(integer(kind=8)) D.4012, 0>). While the RHS 
(expr->ts.u.cl->backend_decl) contained the decl of "..__result".

(I have to admit that I do not fully gasp the code, hence, I do not see 
whether there are other missing cases or whether there are corner cases 
where the patch causes wrong code.)

OK for the trunk and GCC 9?

Tobias

Comments

Thomas Koenig Oct. 30, 2019, 7:06 p.m. UTC | #1 
Hi Tobias,

> OK for the trunk and GCC 9?

As far as I can see, this looks good.

So, OK for trunk. If it later turns out that there are problems
caused by this, I suspect we will hear about them soon enough :-)

Thanks for taking this on!

Regards

	Thomas
Tobias Burnus Nov. 4, 2019, 2:51 p.m. UTC | #2 
On 10/30/19 8:06 PM, Thomas Koenig wrote:
>> OK for the trunk and GCC 9?
>
> As far as I can see, this looks good.
>
> So, OK for trunk. If it later turns out that there are problems
> caused by this, I suspect we will hear about them soon enough :-)

What shall we do about GCC 9? https://gcc.gnu.org/PR92208 is marked as 
9/10 Regression.

We can either say in the PR: Won't fix (for GCC 9) – or we can backport 
the fix to GCC 9.

Suggestions?

Tobias

PS: GCC 9 patch attached (= trunk patch, only line number changes which 
patch handled); builds and regtests on the gcc-9-branch with 
x86_64-gnu-linux.
Thomas König Nov. 4, 2019, 2:59 p.m. UTC | #3 
Hi Tobias,

I think this is also OK for gcc 9. Backporting regression fixes should always be all right under normal circumstances.

Regards

Thomas
diff mbox series

Patch

	PR fortran/92208
	* trans-array.c (gfc_conv_array_parameter): Only copy
	string-length backend_decl if expression is not a function.

	PR fortran/92208
	* gfortran.dg/pr92208.f90: New.

diff --git a/gcc/fortran/trans-array.c b/gcc/fortran/trans-array.c
index 437892a6abf..2d85bf78c42 100644
--- a/gcc/fortran/trans-array.c
+++ b/gcc/fortran/trans-array.c
@@ -8049,7 +8049,7 @@  gfc_conv_array_parameter (gfc_se * se, gfc_expr * expr, bool g77,
 	  /* The components shall be deallocated before their containing entity.  */
 	  gfc_prepend_expr_to_block (&se->post, tmp);
 	}
-      if (expr->ts.type == BT_CHARACTER)
+      if (expr->ts.type == BT_CHARACTER && expr->expr_type != EXPR_FUNCTION)
 	se->string_length = expr->ts.u.cl->backend_decl;
       if (size)
 	array_parameter_size (se->expr, expr, size);
diff --git a/gcc/testsuite/gfortran.dg/pr92208.f90 b/gcc/testsuite/gfortran.dg/pr92208.f90
new file mode 100644
index 00000000000..9de7f4b24b5
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr92208.f90
@@ -0,0 +1,39 @@ 
+! { dg-do run }
+!
+! PR fortran/92208
+!
+! Contributed by Nils Reiche
+!
+program stringtest
+  implicit none
+  integer, parameter :: noVars = 2
+
+!  print*, "varNames: ", createVarnames("var",noVars)
+  call function1(noVars,createVarnames("var",noVars),"path")
+
+contains
+
+function createVarnames(string,noVars) result(stringArray)
+  implicit none
+  character(len=*),                        intent(in)  :: string
+  integer,                                 intent(in)  :: noVars
+  character(len=len_trim(string)+6), dimension(noVars) :: stringArray
+  integer :: i
+  do i=1,noVars
+    write(stringArray(i),'(a,i0)') string, i
+  enddo
+end function createVarnames
+
+subroutine function1(noVars,varNames,path)
+  implicit none
+  integer, intent(in)  :: noVars
+  character(len=*), intent(in)  :: path
+  character(len=*), dimension(noVars) :: varNames
+
+  if (path /= 'path') stop 1
+  if (any(varNames /= ['var1', 'var2'])) stop 2
+  !print*, "function1-path    : ", trim(path)
+  !print*, "function1-varNames: ", varNames
+end subroutine function1
+
+end program stringtest