On Mon, Sep 20, 2021 at 1:33 AM Martin Sebor via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> After the front end passes control to the middle end cfun is never
> null (I'm pretty sure)
cfun is NULL during IPA pass execution, it's set to non-NULL by
the pass manager when we execute a non-IPA pass on a specific
function only.
Richard.
> but when a middle end helper is called
> from the C++ front end cfun can be null for a namespace scope
> initializer expression. A recent change of mine to the helper
> introduced an assumption to the contrary, causing an ICE. In
> r12-3673 I've committed the trivial fix below to correct this
> mistake
>
> Martin
>
> Handle null cfun [PR102243].
>
> Resolves:
> PR middle-end/102243 - ICE on placement new at global scope
>
> gcc/ChangeLog:
> PR middle-end/102243
> * tree-ssa-strlen.c (get_range): Handle null cfun.
>
> gcc/testsuite/ChangeLog:
> PR middle-end/102243
> * g++.dg/warn/Wplacement-new-size-10.C: New test.
> ---
> gcc/testsuite/g++.dg/warn/Wplacement-new-size-10.C | 13 +++++++++++++
> gcc/tree-ssa-strlen.c | 14 ++++++++++----
> 2 files changed, 23 insertions(+), 4 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/warn/Wplacement-new-size-10.C
>
> diff --git a/gcc/testsuite/g++.dg/warn/Wplacement-new-size-10.C
> b/gcc/testsuite/g++.dg/warn/Wplacement-new-size-10.C
> new file mode 100644
> index 00000000000..6b71a832a30
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/warn/Wplacement-new-size-10.C
> @@ -0,0 +1,13 @@
> +/* PR middle-end/102243 - ICE on placement new at global scope
> + { dg-do compile }
> + { dg-options "-Wall" } */
> +
> +void *operator new (__SIZE_TYPE__, void *);
> +
> +char a[2][sizeof (int)];
> +
> +int *p = new (a[1]) int;
> +
> +void *operator new[] (__SIZE_TYPE__, void *p) { return p; }
> +
> +int *q = new (a[1]) int[1];
> diff --git a/gcc/tree-ssa-strlen.c b/gcc/tree-ssa-strlen.c
> index 7c93958e9ad..7c568a42d49 100644
> --- a/gcc/tree-ssa-strlen.c
> +++ b/gcc/tree-ssa-strlen.c
> @@ -199,16 +199,22 @@ static bool handle_assign (gimple_stmt_iterator *,
> tree, bool *,
>
> /* Sets MINMAX to either the constant value or the range VAL is in
> and returns either the constant value or VAL on success or null
> - when the range couldn't be determined. Uses RVALS when nonnull
> - to determine the range, otherwise uses CFUN or global range info,
> - whichever is nonnull. */
> + when the range couldn't be determined. Uses RVALS or CFUN for
> + range info, whichever is nonnull. */
>
> tree
> get_range (tree val, gimple *stmt, wide_int minmax[2],
> range_query *rvals /* = NULL */)
> {
> if (!rvals)
> - rvals = get_range_query (cfun);
> + {
> + if (!cfun)
> + /* When called from front ends for global initializers CFUN
> + may be null. */
> + return NULL_TREE;
> +
> + rvals = get_range_query (cfun);
> + }
>
> value_range vr;
> if (!rvals->range_of_expr (vr, val, stmt))
> --
> 2.27.0
>
