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author | Tim Lange <mail@tim-lange.me> | 2022-08-18 11:36:08 +0200 |
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committer | Tim Lange <mail@tim-lange.me> | 2022-08-18 16:41:56 +0200 |
commit | c83e97317efb87fd5639a9ee9ec55aa1caa5423e (patch) | |
tree | 438c54d1f341f64f7397a25de6a919984f97df55 /gcc/analyzer/region-model.cc | |
parent | 011d0a033ab370ea38b06b813ac62be8dde0801b (diff) | |
download | gcc-c83e97317efb87fd5639a9ee9ec55aa1caa5423e.zip gcc-c83e97317efb87fd5639a9ee9ec55aa1caa5423e.tar.gz gcc-c83e97317efb87fd5639a9ee9ec55aa1caa5423e.tar.bz2 |
analyzer: warn on the use of floating-points operands in the size argument [PR106181]
This patch fixes the ICE reported in PR106181 and adds a new warning to
the analyzer complaining about the use of floating-point operands.
Regrtested on Linux x86_64.
2022-08-17 Tim Lange <mail@tim-lange.me>
gcc/analyzer/ChangeLog:
PR analyzer/106181
* analyzer.opt: Add Wanalyzer-imprecise-floating-point-arithmetic.
* region-model.cc (is_any_cast_p): Formatting.
(region_model::check_region_size): Ensure precondition.
(class imprecise_floating_point_arithmetic): New abstract
diagnostic class for all floating-point related warnings.
(class float_as_size_arg): Concrete diagnostic class to complain
about floating-point operands inside the size argument.
(class contains_floating_point_visitor):
New visitor to find floating-point operands inside svalues.
(region_model::check_dynamic_size_for_floats): New function.
(region_model::set_dynamic_extents):
Call to check_dynamic_size_for_floats.
* region-model.h (class region_model):
Add region_model::check_dynamic_size_for_floats.
gcc/ChangeLog:
PR analyzer/106181
* doc/invoke.texi: Add Wanalyzer-imprecise-fp-arithmetic.
gcc/testsuite/ChangeLog:
PR analyzer/106181
* gcc.dg/analyzer/allocation-size-1.c: New test.
* gcc.dg/analyzer/imprecise-floating-point-1.c: New test.
* gcc.dg/analyzer/pr106181.c: New test.
Diffstat (limited to 'gcc/analyzer/region-model.cc')
-rw-r--r-- | gcc/analyzer/region-model.cc | 179 |
1 files changed, 156 insertions, 23 deletions
diff --git a/gcc/analyzer/region-model.cc b/gcc/analyzer/region-model.cc index b5bc3efd..ec29be2 100644 --- a/gcc/analyzer/region-model.cc +++ b/gcc/analyzer/region-model.cc @@ -3301,7 +3301,8 @@ public: m.add_cwe (131); return warning_meta (rich_loc, m, get_controlling_option (), - "allocated buffer size is not a multiple of the pointee's size"); + "allocated buffer size is not a multiple" + " of the pointee's size"); } label_text @@ -3396,21 +3397,20 @@ capacity_compatible_with_type (tree cst, tree pointee_size_tree) class size_visitor : public visitor { public: - size_visitor (tree size_cst, const svalue *sval, constraint_manager *cm) - : m_size_cst (size_cst), m_sval (sval), m_cm (cm) + size_visitor (tree size_cst, const svalue *root_sval, constraint_manager *cm) + : m_size_cst (size_cst), m_root_sval (root_sval), m_cm (cm) { - sval->accept (this); + m_root_sval->accept (this); } bool get_result () { - return result_set.contains (m_sval); + return result_set.contains (m_root_sval); } void visit_constant_svalue (const constant_svalue *sval) final override { - if (capacity_compatible_with_type (sval->get_constant (), m_size_cst)) - result_set.add (sval); + check_constant (sval->get_constant (), sval); } void visit_unknown_svalue (const unknown_svalue *sval ATTRIBUTE_UNUSED) @@ -3478,15 +3478,10 @@ public: equiv_class_id id (-1); if (m_cm->get_equiv_class_by_svalue (sval, &id)) { - if (tree cst_val = id.get_obj (*m_cm).get_any_constant ()) - { - if (capacity_compatible_with_type (cst_val, m_size_cst)) - result_set.add (sval); - } + if (tree cst = id.get_obj (*m_cm).get_any_constant ()) + check_constant (cst, sval); else - { - result_set.add (sval); - } + result_set.add (sval); } } @@ -3503,8 +3498,23 @@ public: } private: + void check_constant (tree cst, const svalue *sval) + { + switch (TREE_CODE (cst)) + { + default: + /* Assume all unhandled operands are compatible. */ + result_set.add (sval); + break; + case INTEGER_CST: + if (capacity_compatible_with_type (cst, m_size_cst)) + result_set.add (sval); + break; + } + } + tree m_size_cst; - const svalue *m_sval; + const svalue *m_root_sval; constraint_manager *m_cm; svalue_set result_set; /* Used as a mapping of svalue*->bool. */ }; @@ -3541,12 +3551,12 @@ struct_or_union_with_inheritance_p (tree struc) static bool is_any_cast_p (const gimple *stmt) { - if (const gassign *assign = dyn_cast<const gassign *>(stmt)) + if (const gassign *assign = dyn_cast <const gassign *> (stmt)) return gimple_assign_cast_p (assign) || !pending_diagnostic::same_tree_p ( TREE_TYPE (gimple_assign_lhs (assign)), TREE_TYPE (gimple_assign_rhs1 (assign))); - else if (const gcall *call = dyn_cast<const gcall *>(stmt)) + else if (const gcall *call = dyn_cast <const gcall *> (stmt)) { tree lhs = gimple_call_lhs (call); return lhs != NULL_TREE && !pending_diagnostic::same_tree_p ( @@ -3606,10 +3616,11 @@ region_model::check_region_size (const region *lhs_reg, const svalue *rhs_sval, case svalue_kind::SK_CONSTANT: { const constant_svalue *cst_cap_sval - = as_a <const constant_svalue *> (capacity); + = as_a <const constant_svalue *> (capacity); tree cst_cap = cst_cap_sval->get_constant (); - if (!capacity_compatible_with_type (cst_cap, pointee_size_tree, - is_struct)) + if (TREE_CODE (cst_cap) == INTEGER_CST + && !capacity_compatible_with_type (cst_cap, pointee_size_tree, + is_struct)) ctxt->warn (new dubious_allocation_size (lhs_reg, rhs_reg, cst_cap)); } @@ -5055,6 +5066,125 @@ region_model::append_regions_cb (const region *base_reg, cb_data->out->safe_push (decl_reg); } + +/* Abstract class for diagnostics related to the use of + floating-point arithmetic where precision is needed. */ + +class imprecise_floating_point_arithmetic : public pending_diagnostic +{ +public: + int get_controlling_option () const final override + { + return OPT_Wanalyzer_imprecise_fp_arithmetic; + } +}; + +/* Concrete diagnostic to complain about uses of floating-point arithmetic + in the size argument of malloc etc. */ + +class float_as_size_arg : public imprecise_floating_point_arithmetic +{ +public: + float_as_size_arg (tree arg) : m_arg (arg) + {} + + const char *get_kind () const final override + { + return "float_as_size_arg_diagnostic"; + } + + bool subclass_equal_p (const pending_diagnostic &other) const + { + return same_tree_p (m_arg, ((const float_as_size_arg &) other).m_arg); + } + + bool emit (rich_location *rich_loc) final override + { + diagnostic_metadata m; + bool warned = warning_meta (rich_loc, m, get_controlling_option (), + "use of floating-point arithmetic here might" + " yield unexpected results"); + if (warned) + inform (rich_loc->get_loc (), "only use operands of an integer type" + " inside the size argument"); + return warned; + } + + label_text describe_final_event (const evdesc::final_event &ev) final + override + { + if (m_arg) + return ev.formatted_print ("operand %qE is of type %qT", + m_arg, TREE_TYPE (m_arg)); + return ev.formatted_print ("at least one operand of the size argument is" + " of a floating-point type"); + } + +private: + tree m_arg; +}; + +/* Visitor to find uses of floating-point variables/constants in an svalue. */ + +class contains_floating_point_visitor : public visitor +{ +public: + contains_floating_point_visitor (const svalue *root_sval) : m_result (NULL) + { + root_sval->accept (this); + } + + const svalue *get_svalue_to_report () + { + return m_result; + } + + void visit_constant_svalue (const constant_svalue *sval) final override + { + /* At the point the analyzer runs, constant integer operands in a floating + point expression are already implictly converted to floating-points. + Thus, we do prefer to report non-constants such that the diagnostic + always reports a floating-point operand. */ + tree type = sval->get_type (); + if (type && FLOAT_TYPE_P (type) && !m_result) + m_result = sval; + } + + void visit_conjured_svalue (const conjured_svalue *sval) final override + { + tree type = sval->get_type (); + if (type && FLOAT_TYPE_P (type)) + m_result = sval; + } + + void visit_initial_svalue (const initial_svalue *sval) final override + { + tree type = sval->get_type (); + if (type && FLOAT_TYPE_P (type)) + m_result = sval; + } + +private: + /* Non-null if at least one floating-point operand was found. */ + const svalue *m_result; +}; + +/* May complain about uses of floating-point operands in SIZE_IN_BYTES. */ + +void +region_model::check_dynamic_size_for_floats (const svalue *size_in_bytes, + region_model_context *ctxt) const +{ + gcc_assert (ctxt); + + contains_floating_point_visitor v (size_in_bytes); + if (const svalue *float_sval = v.get_svalue_to_report ()) + { + tree diag_arg = get_representative_tree (float_sval); + ctxt->warn (new float_as_size_arg (diag_arg)); + } +} + /* Return a new region describing a heap-allocated block of memory. Use CTXT to complain about tainted sizes. */ @@ -5092,8 +5222,11 @@ region_model::set_dynamic_extents (const region *reg, { assert_compat_types (size_in_bytes->get_type (), size_type_node); if (ctxt) - check_dynamic_size_for_taint (reg->get_memory_space (), size_in_bytes, - ctxt); + { + check_dynamic_size_for_taint (reg->get_memory_space (), size_in_bytes, + ctxt); + check_dynamic_size_for_floats (size_in_bytes, ctxt); + } m_dynamic_extents.put (reg, size_in_bytes); } |