diff options
Diffstat (limited to 'gcc/cp')
| -rw-r--r-- | gcc/cp/ChangeLog | 30 | ||||
| -rw-r--r-- | gcc/cp/call.c | 8 | ||||
| -rw-r--r-- | gcc/cp/cp-tree.h | 31 | ||||
| -rw-r--r-- | gcc/cp/search.c | 240 | ||||
| -rw-r--r-- | gcc/cp/semantics.c | 8 | ||||
| -rw-r--r-- | gcc/cp/typeck.c | 45 |
6 files changed, 351 insertions, 11 deletions
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 228f0ad..d659fb9 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,33 @@ +2017-05-16 David Malcolm <dmalcolm@redhat.com> + + * call.c (enforce_access): Add access_failure_info * param and use + it to record access failures. + * cp-tree.h (class access_failure_info): New class. + (enforce_access): Add access_failure_info * param, defaulting to + NULL. + (lookup_member): Likewise. + (locate_field_accessor): New function decl. + (perform_or_defer_access_check): Add access_failure_info * param, + defaulting to NULL. + * search.c (lookup_member): Add access_failure_info * param and + pass it on to call to perform_or_defer_access_check. + (matches_code_and_type_p): New function. + (field_access_p): New function. + (direct_accessor_p): New function. + (reference_accessor_p): New function. + (field_accessor_p): New function. + (struct locate_field_data): New struct. + (dfs_locate_field_accessor_pre): New function. + (locate_field_accessor): New function. + * semantics.c (perform_or_defer_access_check): Add + access_failure_info * param, and pass it on to call to + enforce_access. + * typeck.c (access_failure_info::record_access_failure): New method. + (access_failure_info::maybe_suggest_accessor): New method. + (finish_class_member_access_expr): Pass an access_failure_info + instance to the lookup_member call, and call its + maybe_suggest_accessor method afterwards. + 2017-05-16 Marek Polacek <polacek@redhat.com> PR sanitizer/80536 diff --git a/gcc/cp/call.c b/gcc/cp/call.c index 1367344..cc64202 100644 --- a/gcc/cp/call.c +++ b/gcc/cp/call.c @@ -6396,7 +6396,7 @@ build_op_delete_call (enum tree_code code, tree addr, tree size, bool enforce_access (tree basetype_path, tree decl, tree diag_decl, - tsubst_flags_t complain) + tsubst_flags_t complain, access_failure_info *afi) { gcc_assert (TREE_CODE (basetype_path) == TREE_BINFO); @@ -6422,17 +6422,23 @@ enforce_access (tree basetype_path, tree decl, tree diag_decl, error ("%q#D is private within this context", diag_decl); inform (DECL_SOURCE_LOCATION (diag_decl), "declared private here"); + if (afi) + afi->record_access_failure (basetype_path, diag_decl); } else if (TREE_PROTECTED (decl)) { error ("%q#D is protected within this context", diag_decl); inform (DECL_SOURCE_LOCATION (diag_decl), "declared protected here"); + if (afi) + afi->record_access_failure (basetype_path, diag_decl); } else { error ("%q#D is inaccessible within this context", diag_decl); inform (DECL_SOURCE_LOCATION (diag_decl), "declared here"); + if (afi) + afi->record_access_failure (basetype_path, diag_decl); } } return false; diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h index 739ff18..0efc5db 100644 --- a/gcc/cp/cp-tree.h +++ b/gcc/cp/cp-tree.h @@ -5758,8 +5758,30 @@ extern bool can_convert_arg (tree, tree, tree, int, tsubst_flags_t); extern bool can_convert_arg_bad (tree, tree, tree, int, tsubst_flags_t); + +/* A class for recording information about access failures (e.g. private + fields), so that we can potentially supply a fix-it hint about + an accessor (from a context in which the constness of the object + is known). */ + +class access_failure_info +{ + public: + access_failure_info () : m_was_inaccessible (false), m_basetype_path (NULL_TREE), + m_field_decl (NULL_TREE) {} + + void record_access_failure (tree basetype_path, tree field_decl); + void maybe_suggest_accessor (bool const_p) const; + + private: + bool m_was_inaccessible; + tree m_basetype_path; + tree m_field_decl; +}; + extern bool enforce_access (tree, tree, tree, - tsubst_flags_t); + tsubst_flags_t, + access_failure_info *afi = NULL); extern void push_defarg_context (tree); extern void pop_defarg_context (void); extern tree convert_default_arg (tree, tree, tree, int, @@ -6412,8 +6434,10 @@ extern tree lookup_fnfields_slot_nolazy (tree, tree); extern int class_method_index_for_fn (tree, tree); extern tree lookup_fnfields (tree, tree, int); extern tree lookup_member (tree, tree, int, bool, - tsubst_flags_t); + tsubst_flags_t, + access_failure_info *afi = NULL); extern tree lookup_member_fuzzy (tree, tree, bool); +extern tree locate_field_accessor (tree, tree, bool); extern int look_for_overrides (tree, tree); extern void get_pure_virtuals (tree); extern void maybe_suppress_debug_info (tree); @@ -6468,7 +6492,8 @@ extern bool perform_access_checks (vec<deferred_access_check, va_gc> *, tsubst_flags_t); extern bool perform_deferred_access_checks (tsubst_flags_t); extern bool perform_or_defer_access_check (tree, tree, tree, - tsubst_flags_t); + tsubst_flags_t, + access_failure_info *afi = NULL); /* RAII sentinel to ensures that deferred access checks are popped before a function returns. */ diff --git a/gcc/cp/search.c b/gcc/cp/search.c index fa72c47..61bdb93 100644 --- a/gcc/cp/search.c +++ b/gcc/cp/search.c @@ -1232,11 +1232,13 @@ build_baselink (tree binfo, tree access_binfo, tree functions, tree optype) WANT_TYPE is 1 when we should only return TYPE_DECLs. - If nothing can be found return NULL_TREE and do not issue an error. */ + If nothing can be found return NULL_TREE and do not issue an error. + + If non-NULL, failure information is written back to AFI. */ tree lookup_member (tree xbasetype, tree name, int protect, bool want_type, - tsubst_flags_t complain) + tsubst_flags_t complain, access_failure_info *afi) { tree rval, rval_binfo = NULL_TREE; tree type = NULL_TREE, basetype_path = NULL_TREE; @@ -1337,7 +1339,7 @@ lookup_member (tree xbasetype, tree name, int protect, bool want_type, tree decl = is_overloaded_fn (rval) ? get_first_fn (rval) : rval; if (!DECL_NONSTATIC_MEMBER_FUNCTION_P (decl) && !perform_or_defer_access_check (basetype_path, decl, decl, - complain)) + complain, afi)) rval = error_mark_node; } @@ -1993,6 +1995,238 @@ dfs_walk_once_accessible (tree binfo, bool friends_p, return rval; } +/* Return true iff the code of T is CODE, and it has compatible + type with TYPE. */ + +static bool +matches_code_and_type_p (tree t, enum tree_code code, tree type) +{ + if (TREE_CODE (t) != code) + return false; + if (!cxx_types_compatible_p (TREE_TYPE (t), type)) + return false; + return true; +} + +/* Subroutine of direct_accessor_p and reference_accessor_p. + Determine if COMPONENT_REF is a simple field lookup of this->FIELD_DECL. + We expect a tree of the form: + <component_ref: + <indirect_ref:S> + <nop_expr:P* + <parm_decl (this)> + <field_decl (FIELD_DECL)>>>. */ + +static bool +field_access_p (tree component_ref, tree field_decl, tree field_type) +{ + if (!matches_code_and_type_p (component_ref, COMPONENT_REF, field_type)) + return false; + + tree indirect_ref = TREE_OPERAND (component_ref, 0); + if (TREE_CODE (indirect_ref) != INDIRECT_REF) + return false; + + tree ptr = STRIP_NOPS (TREE_OPERAND (indirect_ref, 0)); + if (!is_this_parameter (ptr)) + return false; + + /* Must access the correct field. */ + if (TREE_OPERAND (component_ref, 1) != field_decl) + return false; + return true; +} + +/* Subroutine of field_accessor_p. + + Assuming that INIT_EXPR has already had its code and type checked, + determine if it is a simple accessor for FIELD_DECL + (of type FIELD_TYPE). + + Specifically, a simple accessor within struct S of the form: + T get_field () { return m_field; } + should have a DECL_SAVED_TREE of the form: + <return_expr + <init_expr:T + <result_decl:T + <nop_expr:T + <component_ref: + <indirect_ref:S> + <nop_expr:P* + <parm_decl (this)> + <field_decl (FIELD_DECL)>>>. */ + +static bool +direct_accessor_p (tree init_expr, tree field_decl, tree field_type) +{ + tree result_decl = TREE_OPERAND (init_expr, 0); + if (!matches_code_and_type_p (result_decl, RESULT_DECL, field_type)) + return false; + + tree component_ref = STRIP_NOPS (TREE_OPERAND (init_expr, 1)); + if (!field_access_p (component_ref, field_decl, field_type)) + return false; + + return true; +} + +/* Subroutine of field_accessor_p. + + Assuming that INIT_EXPR has already had its code and type checked, + determine if it is a "reference" accessor for FIELD_DECL + (of type FIELD_REFERENCE_TYPE). + + Specifically, a simple accessor within struct S of the form: + T& get_field () { return m_field; } + should have a DECL_SAVED_TREE of the form: + <return_expr + <init_expr:T& + <result_decl:T& + <nop_expr: T& + <addr_expr: T* + <component_ref:T + <indirect_ref:S + <nop_expr + <parm_decl (this)>> + <field (FIELD_DECL)>>>>>>. */ +static bool +reference_accessor_p (tree init_expr, tree field_decl, tree field_type, + tree field_reference_type) +{ + tree result_decl = TREE_OPERAND (init_expr, 0); + if (!matches_code_and_type_p (result_decl, RESULT_DECL, field_reference_type)) + return false; + + tree field_pointer_type = build_pointer_type (field_type); + tree addr_expr = STRIP_NOPS (TREE_OPERAND (init_expr, 1)); + if (!matches_code_and_type_p (addr_expr, ADDR_EXPR, field_pointer_type)) + return false; + + tree component_ref = STRIP_NOPS (TREE_OPERAND (addr_expr, 0)); + + if (!field_access_p (component_ref, field_decl, field_type)) + return false; + + return true; +} + +/* Return true if FN is an accessor method for FIELD_DECL. + i.e. a method of the form { return FIELD; }, with no + conversions. + + If CONST_P, then additionally require that FN be a const + method. */ + +static bool +field_accessor_p (tree fn, tree field_decl, bool const_p) +{ + if (TREE_CODE (fn) != FUNCTION_DECL) + return false; + + /* We don't yet support looking up static data, just fields. */ + if (TREE_CODE (field_decl) != FIELD_DECL) + return false; + + tree fntype = TREE_TYPE (fn); + if (TREE_CODE (fntype) != METHOD_TYPE) + return false; + + /* If the field is accessed via a const "this" argument, verify + that the "this" parameter is const. */ + if (const_p) + { + tree this_type = type_of_this_parm (fntype); + if (!TYPE_READONLY (this_type)) + return false; + } + + tree saved_tree = DECL_SAVED_TREE (fn); + + if (saved_tree == NULL_TREE) + return false; + + if (TREE_CODE (saved_tree) != RETURN_EXPR) + return false; + + tree init_expr = TREE_OPERAND (saved_tree, 0); + if (TREE_CODE (init_expr) != INIT_EXPR) + return false; + + /* Determine if this is a simple accessor within struct S of the form: + T get_field () { return m_field; }. */ + tree field_type = TREE_TYPE (field_decl); + if (cxx_types_compatible_p (TREE_TYPE (init_expr), field_type)) + return direct_accessor_p (init_expr, field_decl, field_type); + + /* Failing that, determine if it is an accessor of the form: + T& get_field () { return m_field; }. */ + tree field_reference_type = cp_build_reference_type (field_type, false); + if (cxx_types_compatible_p (TREE_TYPE (init_expr), field_reference_type)) + return reference_accessor_p (init_expr, field_decl, field_type, + field_reference_type); + + return false; +} + +/* Callback data for dfs_locate_field_accessor_pre. */ + +struct locate_field_data +{ + locate_field_data (tree field_decl_, bool const_p_) + : field_decl (field_decl_), const_p (const_p_) {} + + tree field_decl; + bool const_p; +}; + +/* Return a FUNCTION_DECL that is an "accessor" method for DATA, a FIELD_DECL, + callable via binfo, if one exists, otherwise return NULL_TREE. + + Callback for dfs_walk_once_accessible for use within + locate_field_accessor. */ + +static tree +dfs_locate_field_accessor_pre (tree binfo, void *data) +{ + locate_field_data *lfd = (locate_field_data *)data; + tree type = BINFO_TYPE (binfo); + + vec<tree, va_gc> *method_vec; + tree fn; + size_t i; + + if (!CLASS_TYPE_P (type)) + return NULL_TREE; + + method_vec = CLASSTYPE_METHOD_VEC (type); + if (!method_vec) + return NULL_TREE; + + for (i = 0; vec_safe_iterate (method_vec, i, &fn); ++i) + if (fn) + if (field_accessor_p (fn, lfd->field_decl, lfd->const_p)) + return fn; + + return NULL_TREE; +} + +/* Return a FUNCTION_DECL that is an "accessor" method for FIELD_DECL, + callable via BASETYPE_PATH, if one exists, otherwise return NULL_TREE. */ + +tree +locate_field_accessor (tree basetype_path, tree field_decl, bool const_p) +{ + if (TREE_CODE (basetype_path) != TREE_BINFO) + return NULL_TREE; + + /* Walk the hierarchy, looking for a method of some base class that allows + access to the field. */ + locate_field_data lfd (field_decl, const_p); + return dfs_walk_once_accessible (basetype_path, /*friends=*/true, + dfs_locate_field_accessor_pre, + NULL, &lfd); +} + /* Check that virtual overrider OVERRIDER is acceptable for base function BASEFN. Issue diagnostic, and return zero, if unacceptable. */ diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c index ce2899b..d3249fe 100644 --- a/gcc/cp/semantics.c +++ b/gcc/cp/semantics.c @@ -305,11 +305,13 @@ perform_deferred_access_checks (tsubst_flags_t complain) /* Defer checking the accessibility of DECL, when looked up in BINFO. DIAG_DECL is the declaration to use to print diagnostics. - Return value like perform_access_checks above. */ + Return value like perform_access_checks above. + If non-NULL, report failures to AFI. */ bool perform_or_defer_access_check (tree binfo, tree decl, tree diag_decl, - tsubst_flags_t complain) + tsubst_flags_t complain, + access_failure_info *afi) { int i; deferred_access *ptr; @@ -328,7 +330,7 @@ perform_or_defer_access_check (tree binfo, tree decl, tree diag_decl, /* If we are not supposed to defer access checks, just check now. */ if (ptr->deferring_access_checks_kind == dk_no_deferred) { - bool ok = enforce_access (binfo, decl, diag_decl, complain); + bool ok = enforce_access (binfo, decl, diag_decl, complain, afi); return (complain & tf_error) ? true : ok; } diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c index 46a6bf8..8c94d20 100644 --- a/gcc/cp/typeck.c +++ b/gcc/cp/typeck.c @@ -2647,6 +2647,46 @@ check_template_keyword (tree decl) } } +/* Record that an access failure occurred on BASETYPE_PATH attempting + to access FIELD_DECL. */ + +void +access_failure_info::record_access_failure (tree basetype_path, + tree field_decl) +{ + m_was_inaccessible = true; + m_basetype_path = basetype_path; + m_field_decl = field_decl; +} + +/* If an access failure was recorded, then attempt to locate an + accessor function for the pertinent field, and if one is + available, add a note and fix-it hint suggesting using it. */ + +void +access_failure_info::maybe_suggest_accessor (bool const_p) const +{ + if (!m_was_inaccessible) + return; + + tree accessor + = locate_field_accessor (m_basetype_path, m_field_decl, const_p); + if (!accessor) + return; + + /* The accessor must itself be accessible for it to be a reasonable + suggestion. */ + if (!accessible_p (m_basetype_path, accessor, true)) + return; + + rich_location richloc (line_table, input_location); + pretty_printer pp; + pp_printf (&pp, "%s()", IDENTIFIER_POINTER (DECL_NAME (accessor))); + richloc.add_fixit_replace (pp_formatted_text (&pp)); + inform_at_rich_loc (&richloc, "field %q#D can be accessed via %q#D", + m_field_decl, accessor); +} + /* This function is called by the parser to process a class member access expression of the form OBJECT.NAME. NAME is a node used by the parser to represent a name; it is not yet a DECL. It may, @@ -2829,8 +2869,11 @@ finish_class_member_access_expr (cp_expr object, tree name, bool template_p, else { /* Look up the member. */ + access_failure_info afi; member = lookup_member (access_path, name, /*protect=*/1, - /*want_type=*/false, complain); + /*want_type=*/false, complain, + &afi); + afi.maybe_suggest_accessor (TYPE_READONLY (object_type)); if (member == NULL_TREE) { if (dependent_type_p (object_type)) |