From c77d79785d32b30502c8bcd6aa53b63d715bb124 Mon Sep 17 00:00:00 2001 From: David Faust Date: Wed, 6 Aug 2025 09:24:40 -0700 Subject: ctf: avoid overflow for array num elements [PR121411] CTF array encoding uses uint32 for number of elements. This means there is a hard upper limit on array types which the format can represent. GCC internally was also using a uint32_t for this, which would overflow when translating from DWARF for arrays with more than UINT32_MAX elements. Use an unsigned HOST_WIDE_INT instead to fetch the array bound, and fall back to CTF_K_UNKNOWN if the array cannot be represented in CTF. PR debug/121411 gcc/ * dwarf2ctf.cc (gen_ctf_subrange_type): Use unsigned HWI for array_num_elements. Fallback to CTF_K_UNKNOWN if the array type has too many elements for CTF to represent. gcc/testsuite/ * gcc.dg/debug/ctf/ctf-array-7.c: New test. --- gcc/dwarf2ctf.cc | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'gcc/dwarf2ctf.cc') diff --git a/gcc/dwarf2ctf.cc b/gcc/dwarf2ctf.cc index 7de3696..f8b305b 100644 --- a/gcc/dwarf2ctf.cc +++ b/gcc/dwarf2ctf.cc @@ -361,7 +361,7 @@ gen_ctf_subrange_type (ctf_container_ref ctfc, ctf_dtdef_ref array_elems_type, dw_attr_node *upper_bound_at; dw_die_ref array_index_type; - uint32_t array_num_elements; + unsigned HOST_WIDE_INT array_num_elements; if (dw_get_die_tag (c) == DW_TAG_subrange_type) { @@ -376,9 +376,9 @@ gen_ctf_subrange_type (ctf_container_ref ctfc, ctf_dtdef_ref array_elems_type, if (upper_bound_at && AT_class (upper_bound_at) == dw_val_class_unsigned_const) /* This is the upper bound index. */ - array_num_elements = get_AT_unsigned (c, DW_AT_upper_bound) + 1; + array_num_elements = AT_unsigned (get_AT (c, DW_AT_upper_bound)) + 1; else if (get_AT (c, DW_AT_count)) - array_num_elements = get_AT_unsigned (c, DW_AT_count); + array_num_elements = AT_unsigned (get_AT (c, DW_AT_count)); else { /* This is a VLA of some kind. */ @@ -388,6 +388,12 @@ gen_ctf_subrange_type (ctf_container_ref ctfc, ctf_dtdef_ref array_elems_type, else gcc_unreachable (); + if (array_num_elements > UINT32_MAX) + { + /* The array cannot be encoded in CTF. TBD_CTF_REPRESENTATION_LIMIT. */ + return gen_ctf_unknown_type (ctfc); + } + /* Ok, mount and register the array type. Note how the array type we register here is the type of the elements in subsequent "dimensions", if there are any. */ -- cgit v1.1