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| author | Martin Sebor <msebor@redhat.com> | 2020-09-23 15:19:13 -0600 |
|---|---|---|
| committer | Martin Sebor <msebor@redhat.com> | 2020-09-23 15:19:13 -0600 |
| commit | 67aeddb785ddcc8688ee5736ecab3c81de34a214 (patch) | |
| tree | 39438e9b376232c2094abbfcac4b9452c7c88e4a /gcc | |
| parent | 6edc8f5bfe7d9db8fb8bd37bb8086a69850c6c6d (diff) | |
| download | gcc-67aeddb785ddcc8688ee5736ecab3c81de34a214.zip gcc-67aeddb785ddcc8688ee5736ecab3c81de34a214.tar.gz gcc-67aeddb785ddcc8688ee5736ecab3c81de34a214.tar.bz2 | |
Build a zero element array type that reliably renders as T[0] in diagnostcs.
gcc/ChangeLog:
* gimple-array-bounds.cc (build_zero_elt_array_type): New function.
(array_bounds_checker::check_mem_ref): Call it.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/gimple-array-bounds.cc | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/gcc/gimple-array-bounds.cc b/gcc/gimple-array-bounds.cc index b93ef7a..ab638ba 100644 --- a/gcc/gimple-array-bounds.cc +++ b/gcc/gimple-array-bounds.cc @@ -372,6 +372,20 @@ array_bounds_checker::check_array_ref (location_t location, tree ref, return warned; } +/* Hack around the internal representation constraints and build a zero + element array type that actually renders as T[0] in diagnostcs. */ + +static tree +build_zero_elt_array_type (tree eltype) +{ + tree idxtype = build_range_type (sizetype, size_zero_node, NULL_TREE); + tree arrtype = build_array_type (eltype, idxtype); + arrtype = build_distinct_type_copy (TYPE_MAIN_VARIANT (arrtype)); + TYPE_SIZE (arrtype) = bitsize_zero_node; + TYPE_SIZE_UNIT (arrtype) = size_zero_node; + return arrtype; +} + /* Checks one MEM_REF in REF, located at LOCATION, for out-of-bounds references to string constants. If VRP can determine that the array subscript is a constant, check if it is outside valid range. @@ -547,7 +561,10 @@ array_bounds_checker::check_mem_ref (location_t location, tree ref, return false; offset_int nelts = arrbounds[1] / eltsize; - reftype = build_array_type_nelts (reftype, nelts.to_uhwi ()); + if (nelts == 0) + reftype = build_zero_elt_array_type (reftype); + else + reftype = build_array_type_nelts (reftype, nelts.to_uhwi ()); } else if (TREE_CODE (arg) == ADDR_EXPR) { |