https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106625
--- Comment #2 from CVS Commits ---
The master branch has been updated by Tim Lange :
https://gcc.gnu.org/g:7a6564c9b277d9f93582605758d57457de696deb
commit r13-2546-g7a6564c9b277d9f93582605758d57457de696deb
Author: Tim Lange
Date: Wed Sep 7 17:41:28 2022 +0200
analyzer: support for symbolic values in the out-of-bounds checker
[PR106625]
This patch adds support for reasoning about the inequality of two symbolic
values in the special case specifically suited for reasoning about
out-of-bounds past the end of the buffer. With this patch, the analyzer
catches off-by-one errors and more even when the offset and capacity is
symbolic.
Regrtested on Linux x86_64 and tested on coreutils, curl, httpd and
openssh as usual.
2022-09-07 Tim Lange
gcc/analyzer/ChangeLog:
PR analyzer/106625
* analyzer.h (region_offset): Eliminate m_is_symbolic member.
* region-model-impl-calls.cc (region_model::impl_call_realloc):
Refine implementation to be more precise.
* region-model.cc (class symbolic_past_the_end):
Abstract diagnostic class to complain about accesses past the end
with symbolic values.
(class symbolic_buffer_overflow):
Concrete diagnostic class to complain about buffer overflows with
symbolic values.
(class symbolic_buffer_overread):
Concrete diagnostic class to complain about buffer overreads with
symbolic values.
(region_model::check_symbolic_bounds): New function.
(maybe_get_integer_cst_tree): New helper function.
(region_model::check_region_bounds):
Add call to check_symbolic_bounds if offset is not concrete.
(region_model::eval_condition_without_cm):
Add support for EQ_EXPR and GT_EXPR with binaryop_svalues.
(is_positive_svalue): New hleper function.
(region_model::symbolic_greater_than):
New function to handle GT_EXPR comparisons with symbolic values.
(region_model::structural_equality): New function to compare
whether two svalues are structured the same, i.e. evaluate to
the same value.
(test_struct): Reflect changes to region::calc_offset.
(test_var): Likewise.
(test_array_2): Likewise and add selftest with symbolic i.
* region-model.h (class region_model): Add check_symbolic_bounds,
symbolic_greater_than and structural_equality.
* region.cc (region::get_offset):
Reflect changes to region::calc_offset.
(region::calc_offset):
Compute the symbolic offset if the offset is not concrete.
(region::get_relative_symbolic_offset): New function to return the
symbolic offset in bytes relative to its parent.
(field_region::get_relative_symbolic_offset): Likewise.
(element_region::get_relative_symbolic_offset): Likewise.
(offset_region::get_relative_symbolic_offset): Likewise.
(bit_range_region::get_relative_symbolic_offset): Likewise.
* region.h: Add get_relative_symbolic_offset.
* store.cc (binding_key::make):
Reflect changes to region::calc_offset.
(binding_map::apply_ctor_val_to_range): Likewise.
(binding_map::apply_ctor_pair_to_child_region): Likewise.
(binding_cluster::bind_compound_sval): Likewise.
(binding_cluster::get_any_binding): Likewise.
(binding_cluster::maybe_get_compound_binding): Likewise.
gcc/ChangeLog:
PR analyzer/106625
* doc/invoke.texi:
State that the checker also reasons about symbolic values.
gcc/testsuite/ChangeLog:
PR analyzer/106625
* gcc.dg/analyzer/data-model-1.c: Change expected result.
* gcc.dg/analyzer/out-of-bounds-5.c: New test.
* gcc.dg/analyzer/out-of-bounds-realloc-grow.c: New test.
* gcc.dg/analyzer/symbolic-gt-1.c: New test.
