diff options
Diffstat (limited to 'gcc/cp/constexpr.cc')
| -rw-r--r-- | gcc/cp/constexpr.cc | 2272 |
1 files changed, 1841 insertions, 431 deletions
diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc index 4820bcc..eb19784 100644 --- a/gcc/cp/constexpr.cc +++ b/gcc/cp/constexpr.cc @@ -303,11 +303,20 @@ is_valid_constexpr_fn (tree fun, bool complain) } } } - else if (CLASSTYPE_VBASECLASSES (DECL_CONTEXT (fun))) + else if (CLASSTYPE_VBASECLASSES (DECL_CONTEXT (fun)) && cxx_dialect < cxx26) { ret = false; if (complain) - error ("%q#T has virtual base classes", DECL_CONTEXT (fun)); + { + if (DECL_CONSTRUCTOR_P (fun)) + error ("%<constexpr%> constructor in %q#T that has " + "virtual base classes only available with " + "%<-std=c++2c%> or %<-std=gnu++2c%>", DECL_CONTEXT (fun)); + else + error ("%<constexpr%> destructor in %q#T that has " + "virtual base classes only available with " + "%<-std=c++2c%> or %<-std=gnu++2c%>", DECL_CONTEXT (fun)); + } } return ret; @@ -1048,6 +1057,12 @@ explain_invalid_constexpr_fn (tree fun) { static hash_set<tree> *diagnosed; tree body; + + /* Don't try to explain a function we already complained about. */ + if (function *f = DECL_STRUCT_FUNCTION (fun)) + if (f->language->erroneous) + return; + /* In C++23, a function marked 'constexpr' may not actually be a constant expression. We haven't diagnosed the problem yet: -Winvalid-constexpr wasn't enabled. The function was called, so diagnose why it cannot be @@ -1097,17 +1112,14 @@ explain_invalid_constexpr_fn (tree fun) body = fd->body; else body = DECL_SAVED_TREE (fun); - body = massage_constexpr_body (fun, body); - require_potential_rvalue_constant_expression (body); + tree massaged = massage_constexpr_body (fun, body); + require_potential_rvalue_constant_expression (massaged); if (DECL_CONSTRUCTOR_P (fun)) { - cx_check_missing_mem_inits (DECL_CONTEXT (fun), body, true); + cx_check_missing_mem_inits (DECL_CONTEXT (fun), massaged, true); if (cxx_dialect > cxx11) - { - /* Also check the body, not just the ctor-initializer. */ - body = DECL_SAVED_TREE (fun); - require_potential_rvalue_constant_expression (body); - } + /* Also check the body, not just the ctor-initializer. */ + require_potential_rvalue_constant_expression (body); } } } @@ -1119,20 +1131,22 @@ explain_invalid_constexpr_fn (tree fun) struct GTY((for_user)) constexpr_call { /* Description of the constexpr function definition. */ - constexpr_fundef *fundef; + constexpr_fundef *fundef = nullptr; /* Parameter bindings environment. A TREE_VEC of arguments. */ - tree bindings; - /* Result of the call. - NULL means the call is being evaluated. + tree bindings = NULL_TREE; + /* Result of the call, indexed by the value of + constexpr_ctx::manifestly_const_eval. + unknown_type_node means the call is being evaluated. error_mark_node means that the evaluation was erroneous or otherwise uncacheable (e.g. because it depends on the caller). Otherwise, the actual value of the call. */ - tree result; + tree results[3] = { NULL_TREE, NULL_TREE, NULL_TREE }; /* The hash of this call; we remember it here to avoid having to recalculate it when expanding the hash table. */ - hashval_t hash; - /* The value of constexpr_ctx::manifestly_const_eval. */ - enum mce_value manifestly_const_eval; + hashval_t hash = 0; + + /* The result slot corresponding to the given mce_value. */ + tree& result (mce_value mce) { return results[1 + int(mce)]; } }; struct constexpr_call_hasher : ggc_ptr_hash<constexpr_call> @@ -1170,6 +1184,10 @@ public: /* Heap VAR_DECLs created during the evaluation of the outermost constant expression. */ auto_vec<tree, 16> heap_vars; + /* Vector of caught exceptions, including exceptions still not active at + the start of a handler (those are immediately followed up by HANDLER_TYPE + until __cxa_begin_catch finishes). */ + auto_vec<tree, 2> caught_exceptions; /* Cleanups that need to be evaluated at the end of CLEANUP_POINT_EXPR. */ vec<tree> *cleanups; /* If non-null, only allow modification of existing values of the variables @@ -1177,10 +1195,13 @@ public: hash_set<tree> *modifiable; /* Number of heap VAR_DECL deallocations. */ unsigned heap_dealloc_count; + /* Number of uncaught exceptions. */ + unsigned uncaught_exceptions; + /* Constructor. */ constexpr_global_ctx () : constexpr_ops_count (0), cleanups (NULL), modifiable (nullptr), - heap_dealloc_count (0) {} + heap_dealloc_count (0), uncaught_exceptions (0) {} bool is_outside_lifetime (tree t) { @@ -1294,6 +1315,64 @@ struct constexpr_ctx { mce_value manifestly_const_eval; }; +/* Predicates for the meaning of *jump_target. */ + +static bool +returns (tree *jump_target) +{ + return *jump_target && TREE_CODE (*jump_target) == RETURN_EXPR; +} + +static bool +breaks (tree *jump_target) +{ + return (*jump_target + && ((TREE_CODE (*jump_target) == LABEL_DECL + && LABEL_DECL_BREAK (*jump_target)) + || TREE_CODE (*jump_target) == BREAK_STMT + || TREE_CODE (*jump_target) == EXIT_EXPR)); +} + +static bool +continues (tree *jump_target) +{ + return (*jump_target + && ((TREE_CODE (*jump_target) == LABEL_DECL + && LABEL_DECL_CONTINUE (*jump_target)) + || TREE_CODE (*jump_target) == CONTINUE_STMT)); +} + +static bool +switches (tree *jump_target) +{ + return *jump_target && TREE_CODE (*jump_target) == INTEGER_CST; +} + +static bool +throws (tree *jump_target) +{ + /* void_node is for use in potential_constant_expression_1, otherwise + it should an artificial VAR_DECL created by constant evaluation + of __cxa_allocate_exception (). */ + return (*jump_target && (VAR_P (*jump_target) || *jump_target == void_node)); +} + +/* True if the constexpr relaxations afforded by P2280R4 for unknown + references and objects are in effect. */ + +static bool +p2280_active_p (const constexpr_ctx *ctx) +{ + if (ctx->manifestly_const_eval != mce_true) + /* Disable these relaxations during speculative constexpr folding, + as it can significantly increase compile time/memory use + (PR119387). */ + return false; + + /* P2280R4 was accepted as a DR against C++11. */ + return cxx_dialect >= cxx11; +} + /* Remove T from the global values map, checking for attempts to destroy a value that has already finished its lifetime. */ @@ -1411,8 +1490,6 @@ constexpr_call_hasher::equal (constexpr_call *lhs, constexpr_call *rhs) return true; if (lhs->hash != rhs->hash) return false; - if (lhs->manifestly_const_eval != rhs->manifestly_const_eval) - return false; if (!constexpr_fundef_hasher::equal (lhs->fundef, rhs->fundef)) return false; return cp_tree_equal (lhs->bindings, rhs->bindings); @@ -1515,13 +1592,671 @@ enum value_cat { }; static tree cxx_eval_constant_expression (const constexpr_ctx *, tree, - value_cat, bool *, bool *, tree * = NULL); + value_cat, bool *, bool *, tree *); static tree cxx_eval_bare_aggregate (const constexpr_ctx *, tree, - value_cat, bool *, bool *); + value_cat, bool *, bool *, tree *); static tree cxx_fold_indirect_ref (const constexpr_ctx *, location_t, tree, tree, - bool * = NULL); + bool *, tree *); static tree find_heap_var_refs (tree *, int *, void *); -static tree find_deleted_heap_var (tree *, int *, void *); + +/* For exception object EXC if it has class type and usable what () method + which returns cv char * return the xmalloced string literal which it returns + if possible, otherwise return NULL. */ + +static char * +exception_what_str (const constexpr_ctx *ctx, tree exc) +{ + tree type = strip_array_types (TREE_TYPE (exc)); + if (!CLASS_TYPE_P (type)) + return NULL; + tree std_exception = lookup_qualified_name (std_node, "exception", + LOOK_want::NORMAL, false); + if (TREE_CODE (std_exception) != TYPE_DECL) + return NULL; + if (!CLASS_TYPE_P (TREE_TYPE (std_exception))) + return NULL; + base_kind b_kind; + tree binfo = lookup_base (type, TREE_TYPE (std_exception), ba_check, &b_kind, + tf_none); + if (binfo == NULL_TREE || binfo == error_mark_node) + return NULL; + if (type != TREE_TYPE (exc)) + exc = build4 (ARRAY_REF, type, exc, size_zero_node, NULL, NULL); + tree call + = finish_class_member_access_expr (exc, get_identifier ("what"), false, + tf_none); + if (call == error_mark_node) + return NULL; + releasing_vec what_args; + call = finish_call_expr (call, &what_args, false, false, tf_none); + if (call == error_mark_node) + return NULL; + if (TREE_CODE (TREE_TYPE (call)) != POINTER_TYPE + || !INTEGRAL_TYPE_P (TREE_TYPE (TREE_TYPE (call))) + || !COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (call))) + || !tree_int_cst_equal (TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (call))), + TYPE_SIZE_UNIT (char_type_node)) + || TYPE_PRECISION (TREE_TYPE (TREE_TYPE (call))) != BITS_PER_UNIT) + return NULL; + if (!potential_constant_expression (call)) + return NULL; + bool non_constant_p = false, overflow_p = false; + tree jmp_target = NULL; + tree ptr = cxx_eval_constant_expression (ctx, call, vc_prvalue, + &non_constant_p, &overflow_p, + &jmp_target); + if (throws (&jmp_target) || non_constant_p) + return NULL; + if (reduced_constant_expression_p (ptr)) + if (const char *msg = c_getstr (ptr)) + return xstrdup (msg); + auto_vec <char, 32> v; + for (unsigned i = 0; i < INT_MAX; ++i) + { + tree t = call; + if (i) + t = build2 (POINTER_PLUS_EXPR, TREE_TYPE (ptr), ptr, size_int (i)); + t = build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (t)), t); + non_constant_p = false; + overflow_p = false; + jmp_target = NULL; + tree t2 = cxx_eval_constant_expression (ctx, t, vc_prvalue, + &non_constant_p, &overflow_p, + &jmp_target); + if (throws (&jmp_target) + || non_constant_p + || !tree_fits_shwi_p (t2)) + return NULL; + char c = tree_to_shwi (t2); + v.safe_push (c); + if (c == '\0') + break; + } + return xstrdup (v.address ()); +} + +/* Diagnose constant expression evaluation encountering call to + std::terminate due to exception EXC. */ + +static void +diagnose_std_terminate (location_t loc, const constexpr_ctx *ctx, tree exc) +{ + tree type = strip_array_types (TREE_TYPE (exc)); + if (char *str = exception_what_str (ctx, exc)) + { + error_at (loc, "%qs called after throwing an exception of type %qT; " + "%<what()%>: %qs", "std::terminate", type, str); + free (str); + } + else + { + if (type != TREE_TYPE (exc)) + exc = build4 (ARRAY_REF, type, exc, size_zero_node, NULL, NULL); + bool non_constant_p = false, overflow_p = false; + tree jmp_target = NULL; + tree val = cxx_eval_constant_expression (ctx, exc, vc_prvalue, + &non_constant_p, &overflow_p, + &jmp_target); + gcc_assert (!throws (&jmp_target) && !non_constant_p); + if (reduced_constant_expression_p (val)) + error_at (loc, "%qs called after throwing an exception %qE", + "std::terminate", val); + else + error_at (loc, "%qs called after throwing an exception of type %qT", + "std::terminate", type); + } +} + +/* Diagnose constant expression evaluation encountering call to + uncaught exception EXC. */ + +static void +diagnose_uncaught_exception (location_t loc, const constexpr_ctx *ctx, tree exc) +{ + tree type = strip_array_types (TREE_TYPE (exc)); + if (char *str = exception_what_str (ctx, exc)) + { + error_at (loc, "uncaught exception of type %qT; %<what()%>: %qs", type, str); + free (str); + } + else + { + if (type != TREE_TYPE (exc)) + exc = build4 (ARRAY_REF, type, exc, size_zero_node, NULL, NULL); + bool non_constant_p = false, overflow_p = false; + tree jmp_target = NULL; + tree val = cxx_eval_constant_expression (ctx, exc, vc_prvalue, + &non_constant_p, &overflow_p, + &jmp_target); + gcc_assert (!throws (&jmp_target) && !non_constant_p); + if (reduced_constant_expression_p (val)) + error_at (loc, "uncaught exception %qE", val); + else + error_at (loc, "uncaught exception of type %qT", type); + } +} + +/* Kinds of __cxa_* functions (and a few other EH related ones) we handle as + magic constexpr functions for C++26. */ + +enum cxa_builtin { + CXA_NONE = 0, + CXA_ALLOCATE_EXCEPTION = 1, + CXA_FREE_EXCEPTION = 2, + CXA_THROW = 3, + CXA_BEGIN_CATCH = 4, + CXA_END_CATCH = 5, + CXA_RETHROW = 6, + CXA_GET_EXCEPTION_PTR = 7, + CXA_BAD_CAST = 8, + CXA_BAD_TYPEID = 9, + CXA_THROW_BAD_ARRAY_NEW_LENGTH = 10, + STD_UNCAUGHT_EXCEPTIONS = 11, + STD_CURRENT_EXCEPTION = 12, + STD_RETHROW_EXCEPTION = 13, + BUILTIN_EH_PTR_ADJUST_REF = 14 +}; + +/* Return cxa_builtin if FNDECL is a __cxa_* function handled as + magic constexpr function for C++26. Return CXA_NONE otherwise. */ + +static enum cxa_builtin +cxx_cxa_builtin_fn_p (tree fndecl) +{ + if (cxx_dialect < cxx26) + return CXA_NONE; + if (DECL_LANGUAGE (fndecl) != lang_c) + { + if (!decl_in_std_namespace_p (fndecl)) + return CXA_NONE; + if (id_equal (DECL_NAME (fndecl), "uncaught_exceptions")) + return STD_UNCAUGHT_EXCEPTIONS; + if (id_equal (DECL_NAME (fndecl), "current_exception")) + return STD_CURRENT_EXCEPTION; + if (id_equal (DECL_NAME (fndecl), "rethrow_exception")) + return STD_RETHROW_EXCEPTION; + return CXA_NONE; + } + if (!startswith (IDENTIFIER_POINTER (DECL_NAME (fndecl)), "__cxa_")) + return CXA_NONE; + if (id_equal (DECL_NAME (fndecl), "__cxa_allocate_exception")) + return CXA_ALLOCATE_EXCEPTION; + if (id_equal (DECL_NAME (fndecl), "__cxa_free_exception")) + return CXA_FREE_EXCEPTION; + if (id_equal (DECL_NAME (fndecl), "__cxa_throw")) + return CXA_THROW; + if (id_equal (DECL_NAME (fndecl), "__cxa_begin_catch")) + return CXA_BEGIN_CATCH; + if (id_equal (DECL_NAME (fndecl), "__cxa_end_catch")) + return CXA_END_CATCH; + if (id_equal (DECL_NAME (fndecl), "__cxa_rethrow")) + return CXA_RETHROW; + if (id_equal (DECL_NAME (fndecl), "__cxa_get_exception_ptr")) + return CXA_GET_EXCEPTION_PTR; + if (id_equal (DECL_NAME (fndecl), "__cxa_bad_cast")) + return CXA_BAD_CAST; + if (id_equal (DECL_NAME (fndecl), "__cxa_bad_typeid")) + return CXA_BAD_TYPEID; + if (id_equal (DECL_NAME (fndecl), "__cxa_throw_bad_array_new_length")) + return CXA_THROW_BAD_ARRAY_NEW_LENGTH; + return CXA_NONE; +} + +/* Helper function for cxx_eval_cxa_builtin_fn. + Check if ARG is a valid first argument of __cxa_throw or + __cxa_free_exception or __builtin_eh_ptr_adjust_ref. Return NULL_TREE if + not, otherwise return the artificial __cxa_allocate_exception allocated + VAR_DECL. FREE_EXC is true for __cxa_free_exception, false otherwise. */ + +static tree +cxa_check_throw_arg (tree arg, bool free_exc) +{ + STRIP_NOPS (arg); + if (TREE_CODE (arg) != ADDR_EXPR) + return NULL_TREE; + arg = TREE_OPERAND (arg, 0); + if (!VAR_P (arg) + || !DECL_ARTIFICIAL (arg) + || ((!free_exc || DECL_NAME (arg) != heap_uninit_identifier) + && DECL_NAME (arg) != heap_identifier) + || !DECL_LANG_SPECIFIC (arg)) + return NULL_TREE; + return arg; +} + +/* Helper function for cxx_eval_cxa_builtin_fn. + "Allocate" on the constexpr heap an exception object of TYPE + with REFCOUNT. */ + +static tree +cxa_allocate_exception (location_t loc, const constexpr_ctx *ctx, tree type, + tree refcount) +{ + tree var = build_decl (loc, VAR_DECL, heap_uninit_identifier, type); + DECL_ARTIFICIAL (var) = 1; + retrofit_lang_decl (var); + DECL_EXCEPTION_REFCOUNT (var) = refcount; + ctx->global->heap_vars.safe_push (var); + return var; +} + +/* Evaluate various __cxa_* calls as magic constexpr builtins for + C++26 constexpr exception support (P3068R5). */ + +static tree +cxx_eval_cxa_builtin_fn (const constexpr_ctx *ctx, tree call, + enum cxa_builtin kind, tree fndecl, + bool *non_constant_p, bool *overflow_p, + tree *jump_target) +{ + int nargs = call_expr_nargs (call); + location_t loc = cp_expr_loc_or_input_loc (call); + tree args[4], arg; + if (nargs > 4) + { + invalid_nargs: + if (!ctx->quiet) + error_at (loc, "call to %qD function with incorrect" + "number of arguments", fndecl); + *non_constant_p = true; + return call; + } + if ((kind == CXA_BEGIN_CATCH || kind == CXA_GET_EXCEPTION_PTR) + && nargs == 1 + && (arg = CALL_EXPR_ARG (call, 0)) + && TREE_CODE (arg) == CALL_EXPR + && call_expr_nargs (arg) == 1 + && integer_zerop (CALL_EXPR_ARG (arg, 0))) + if (tree fun = get_function_named_in_call (arg)) + if (fndecl_built_in_p (fun, BUILT_IN_EH_POINTER)) + { + if (ctx->global->caught_exceptions.length () < 2) + { + no_caught_exceptions: + if (!ctx->quiet) + error_at (loc, "%qD called with no caught exceptions pending", + fndecl); + *non_constant_p = true; + return call; + } + /* Both __cxa_get_exception_ptr (__builtin_eh_pointer (0)) + and __cxa_begin_catch (__builtin_eh_pointer (0)) calls expect + ctx->global->caught_exceptions vector to end with + __cxa_allocate_exception created artificial VAR_DECL (the + exception object) followed by handler type, pushed by TRY_BLOCK + evaluation. The only difference between the functions is that + __cxa_begin_catch pops the handler type from the vector and keeps + the VAR_DECL last and decreases uncaught_exceptions. The + VAR_DECL after __cxa_begin_catch serves as the current exception + and is then popped in __cxa_end_catch evaluation. */ + tree handler_type = ctx->global->caught_exceptions.last (); + if (handler_type && VAR_P (handler_type)) + goto no_caught_exceptions; + unsigned idx = ctx->global->caught_exceptions.length () - 2; + arg = ctx->global->caught_exceptions[idx]; + gcc_assert (VAR_P (arg)); + if (kind == CXA_BEGIN_CATCH) + { + ctx->global->caught_exceptions.pop (); + --ctx->global->uncaught_exceptions; + } + if (handler_type == NULL_TREE) + /* Used for catch (...). Just return void. */ + return void_node; + else if (POINTER_TYPE_P (handler_type)) + { + /* Used for catch of a pointer. */ + if (TREE_CODE (TREE_TYPE (arg)) == ARRAY_TYPE) + arg = build4 (ARRAY_REF, TREE_TYPE (TREE_TYPE (arg)), arg, + size_zero_node, NULL_TREE, NULL_TREE); + arg = cp_convert (handler_type, arg, + ctx->quiet ? tf_none : tf_warning_or_error); + if (arg == error_mark_node) + { + *non_constant_p = true; + return call; + } + } + else + { + /* Used for catch of a non-pointer type. */ + tree exc_type = strip_array_types (TREE_TYPE (arg)); + tree exc_ptr_type = build_pointer_type (exc_type); + arg = build_fold_addr_expr_with_type (arg, exc_ptr_type); + if (CLASS_TYPE_P (handler_type)) + { + tree ptr_type = build_pointer_type (handler_type); + arg = cp_convert (ptr_type, arg, + ctx->quiet ? tf_none + : tf_warning_or_error); + if (arg == error_mark_node) + { + *non_constant_p = true; + return call; + } + } + } + return cxx_eval_constant_expression (ctx, arg, vc_prvalue, + non_constant_p, overflow_p, + jump_target); + } + for (int i = 0; i < nargs; ++i) + { + args[i] = cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (call, i), + vc_prvalue, non_constant_p, + overflow_p, jump_target); + if (*non_constant_p) + return call; + if (*jump_target) + return NULL_TREE; + } + switch (kind) + { + case CXA_ALLOCATE_EXCEPTION: + if (nargs != 1) + goto invalid_nargs; + if (!tree_fits_uhwi_p (args[0])) + { + if (!ctx->quiet) + error_at (loc, "cannot allocate exception: size not constant"); + *non_constant_p = true; + return call; + } + else + { + tree type = build_array_type_nelts (char_type_node, + tree_to_uhwi (args[0])); + tree var = cxa_allocate_exception (loc, ctx, type, size_zero_node); + ctx->global->put_value (var, NULL_TREE); + return fold_convert (ptr_type_node, build_address (var)); + } + case CXA_FREE_EXCEPTION: + if (nargs != 1) + goto invalid_nargs; + arg = cxa_check_throw_arg (args[0], true); + if (arg == NULL_TREE) + { + invalid_ptr: + if (!ctx->quiet) + error_at (loc, "first argument to %qD function not result of " + "%<__cxa_allocate_exception%>", fndecl); + *non_constant_p = true; + return call; + } + DECL_NAME (arg) = heap_deleted_identifier; + ctx->global->destroy_value (arg); + ctx->global->heap_dealloc_count++; + return void_node; + case CXA_THROW: + if (nargs != 3) + goto invalid_nargs; + arg = cxa_check_throw_arg (args[0], false); + if (arg == NULL_TREE) + goto invalid_ptr; + DECL_EXCEPTION_REFCOUNT (arg) + = size_binop (PLUS_EXPR, DECL_EXCEPTION_REFCOUNT (arg), + size_one_node); + ++ctx->global->uncaught_exceptions; + *jump_target = arg; + return void_node; + case CXA_BEGIN_CATCH: + case CXA_GET_EXCEPTION_PTR: + goto invalid_nargs; + case CXA_END_CATCH: + if (nargs != 0) + goto invalid_nargs; + if (ctx->global->caught_exceptions.is_empty ()) + { + no_active_exc: + if (!ctx->quiet) + error_at (loc, "%qD called with no caught exceptions active", + fndecl); + *non_constant_p = true; + return call; + } + else + { + arg = ctx->global->caught_exceptions.pop (); + if (arg == NULL_TREE || !VAR_P (arg)) + goto no_active_exc; + free_except: + DECL_EXCEPTION_REFCOUNT (arg) + = size_binop (MINUS_EXPR, DECL_EXCEPTION_REFCOUNT (arg), + size_one_node); + if (integer_zerop (DECL_EXCEPTION_REFCOUNT (arg))) + { + if (type_build_dtor_call (TREE_TYPE (arg))) + { + tree cleanup + = cxx_maybe_build_cleanup (arg, (ctx->quiet ? tf_none + : tf_warning_or_error)); + if (cleanup == error_mark_node) + *non_constant_p = true; + tree jmp_target = NULL_TREE; + cxx_eval_constant_expression (ctx, cleanup, vc_discard, + non_constant_p, overflow_p, + &jmp_target); + if (throws (&jmp_target)) + *jump_target = jmp_target; + } + DECL_NAME (arg) = heap_deleted_identifier; + ctx->global->destroy_value (arg); + ctx->global->heap_dealloc_count++; + } + } + return void_node; + case CXA_RETHROW: + if (nargs != 0) + goto invalid_nargs; + unsigned idx; + FOR_EACH_VEC_ELT_REVERSE (ctx->global->caught_exceptions, idx, arg) + if (arg == NULL_TREE || !VAR_P (arg)) + --idx; + else + break; + if (arg == NULL_TREE) + { + if (!ctx->quiet) + error_at (loc, "%qD called with no caught exceptions active", + fndecl); + *non_constant_p = true; + return call; + } + DECL_EXCEPTION_REFCOUNT (arg) + = size_binop (PLUS_EXPR, DECL_EXCEPTION_REFCOUNT (arg), size_one_node); + ++ctx->global->uncaught_exceptions; + *jump_target = arg; + return void_node; + case CXA_BAD_CAST: + case CXA_BAD_TYPEID: + case CXA_THROW_BAD_ARRAY_NEW_LENGTH: + if (nargs != 0) + goto invalid_nargs; + else + { + tree name; + switch (kind) + { + case CXA_BAD_CAST: + name = get_identifier ("bad_cast"); + break; + case CXA_BAD_TYPEID: + name = get_identifier ("bad_typeid"); + break; + case CXA_THROW_BAD_ARRAY_NEW_LENGTH: + name = get_identifier ("bad_array_new_length"); + break; + default: + gcc_unreachable (); + } + tree decl = lookup_qualified_name (std_node, name); + if (TREE_CODE (decl) != TYPE_DECL + || !CLASS_TYPE_P (TREE_TYPE (decl)) + || !type_build_ctor_call (TREE_TYPE (decl))) + { + if (!ctx->quiet) + error_at (loc, "%qD called without %<std::%D%> being defined", + fndecl, name); + *non_constant_p = true; + return call; + } + tree type = TREE_TYPE (decl); + tree var = cxa_allocate_exception (loc, ctx, type, size_one_node); + tree ctor + = build_special_member_call (var, complete_ctor_identifier, + NULL, type, LOOKUP_NORMAL, + ctx->quiet ? tf_none + : tf_warning_or_error); + if (ctor == error_mark_node) + { + *non_constant_p = true; + return call; + } + if (TREE_CONSTANT (ctor)) + ctx->global->put_value (var, ctor); + else + { + ctx->global->put_value (var, NULL_TREE); + cxx_eval_constant_expression (ctx, ctor, vc_discard, + non_constant_p, overflow_p, + jump_target); + if (*non_constant_p) + return call; + if (throws (jump_target)) + return NULL_TREE; + } + ++ctx->global->uncaught_exceptions; + *jump_target = var; + } + return void_node; + case STD_UNCAUGHT_EXCEPTIONS: + if (nargs != 0) + goto invalid_nargs; + /* Similarly to __builtin_is_constant_evaluated (), we don't + want to give a definite answer during mce_unknown evaluation, + because that might prevent evaluation later on when some + exceptions might be uncaught. But unlike that, we don't + want to constant fold it even during cp_fold, because at runtime + std::uncaught_exceptions () might still be non-zero. */ + if (ctx->manifestly_const_eval != mce_true) + { + *non_constant_p = true; + return call; + } + return build_int_cst (integer_type_node, + ctx->global->uncaught_exceptions); + case STD_CURRENT_EXCEPTION: + if (nargs != 0) + goto invalid_nargs; + else + { + tree name = get_identifier ("exception_ptr"); + tree decl = lookup_qualified_name (std_node, name); + tree fld; + if (TREE_CODE (decl) != TYPE_DECL + || !CLASS_TYPE_P (TREE_TYPE (decl)) + || !COMPLETE_TYPE_P (TREE_TYPE (decl)) + || !(fld = next_aggregate_field (TYPE_FIELDS (TREE_TYPE (decl)))) + || DECL_ARTIFICIAL (fld) + || TREE_CODE (TREE_TYPE (fld)) != POINTER_TYPE + || next_aggregate_field (DECL_CHAIN (fld)) + || !tree_int_cst_equal (TYPE_SIZE (TREE_TYPE (decl)), + TYPE_SIZE (TREE_TYPE (fld)))) + { + if (!ctx->quiet) + error_at (loc, "%qD called without supportable %qs", + fndecl, "std::exception_ptr"); + *non_constant_p = true; + return call; + } + FOR_EACH_VEC_ELT_REVERSE (ctx->global->caught_exceptions, idx, arg) + if (arg == NULL_TREE || !VAR_P (arg)) + --idx; + else + break; + /* Similarly to __builtin_is_constant_evaluated (), we don't + want to give a definite answer during mce_unknown evaluation, + because that might prevent evaluation later on when some + exceptions might be current. But unlike that, we don't + want to constant fold it to null even during cp_fold, because + at runtime std::current_exception () might still be non-null. */ + if (ctx->manifestly_const_eval != mce_true && arg == NULL_TREE) + { + *non_constant_p = true; + return call; + } + if (arg == NULL_TREE) + arg = build_zero_cst (TREE_TYPE (fld)); + else + { + DECL_EXCEPTION_REFCOUNT (arg) + = size_binop (PLUS_EXPR, DECL_EXCEPTION_REFCOUNT (arg), + size_one_node); + arg = fold_convert (ptr_type_node, build_address (arg)); + } + return build_constructor_single (TREE_TYPE (decl), fld, arg); + } + case STD_RETHROW_EXCEPTION: + if (nargs != 1) + goto invalid_nargs; + if (TYPE_REF_P (TREE_TYPE (args[0]))) + { + arg = args[0]; + STRIP_NOPS (arg); + if (TREE_CODE (arg) == ADDR_EXPR) + { + args[0] + = cxx_eval_constant_expression (ctx, TREE_OPERAND (arg, 0), + vc_prvalue, non_constant_p, + overflow_p, jump_target); + if (*non_constant_p) + return call; + if (*jump_target) + return NULL_TREE; + } + } + if (TREE_CODE (args[0]) != CONSTRUCTOR + || CONSTRUCTOR_NELTS (args[0]) != 1) + { + invalid_std_rethrow: + if (!ctx->quiet) + error_at (loc, "%qD called with unexpected %qs argument", + fndecl, "std::exception_ptr"); + *non_constant_p = true; + return void_node; + } + arg = cxa_check_throw_arg (CONSTRUCTOR_ELT (args[0], 0)->value, false); + if (arg == NULL_TREE) + goto invalid_std_rethrow; + DECL_EXCEPTION_REFCOUNT (arg) + = size_binop (PLUS_EXPR, DECL_EXCEPTION_REFCOUNT (arg), size_one_node); + ++ctx->global->uncaught_exceptions; + *jump_target = arg; + return void_node; + case BUILTIN_EH_PTR_ADJUST_REF: + if (nargs != 2) + goto invalid_nargs; + arg = cxa_check_throw_arg (args[0], false); + if (arg == NULL_TREE) + goto invalid_ptr; + if (integer_onep (args[1])) + DECL_EXCEPTION_REFCOUNT (arg) + = size_binop (PLUS_EXPR, DECL_EXCEPTION_REFCOUNT (arg), + size_one_node); + else if (integer_minus_onep (args[1])) + goto free_except; + else + { + if (!ctx->quiet) + error_at (loc, "%qD called with second argument " + "other than 1 or -1", fndecl); + *non_constant_p = true; + } + return void_node; + default: + gcc_unreachable (); + } +} /* Attempt to evaluate T which represents a call to a builtin function. We assume here that all builtin functions evaluate to scalar types @@ -1530,7 +2265,8 @@ static tree find_deleted_heap_var (tree *, int *, void *); static tree cxx_eval_builtin_function_call (const constexpr_ctx *ctx, tree t, tree fun, value_cat lval, - bool *non_constant_p, bool *overflow_p) + bool *non_constant_p, bool *overflow_p, + tree *jump_target) { const int nargs = call_expr_nargs (t); tree *args = (tree *) alloca (nargs * sizeof (tree)); @@ -1576,6 +2312,12 @@ cxx_eval_builtin_function_call (const constexpr_ctx *ctx, tree t, tree fun, return fold_builtin_source_location (t); } + if (fndecl_built_in_p (fun, CP_BUILT_IN_EH_PTR_ADJUST_REF, + BUILT_IN_FRONTEND)) + return cxx_eval_cxa_builtin_fn (ctx, t, BUILTIN_EH_PTR_ADJUST_REF, + fun, non_constant_p, overflow_p, + jump_target); + int strops = 0; int strret = 0; if (fndecl_built_in_p (fun, BUILT_IN_NORMAL)) @@ -1650,8 +2392,14 @@ cxx_eval_builtin_function_call (const constexpr_ctx *ctx, tree t, tree fun, || potential_constant_expression (arg)) { bool dummy1 = false, dummy2 = false; + tree jmp_target = NULL_TREE; arg = cxx_eval_constant_expression (&new_ctx, arg, vc_prvalue, - &dummy1, &dummy2); + &dummy1, &dummy2, &jmp_target); + if (jmp_target) + { + *jump_target = jmp_target; + return NULL_TREE; + } } if (bi_const_p) @@ -1740,7 +2488,8 @@ cxx_eval_builtin_function_call (const constexpr_ctx *ctx, tree t, tree fun, } return cxx_eval_constant_expression (&new_ctx, new_call, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); } /* TEMP is the constant value of a temporary object of type TYPE. Adjust @@ -1854,20 +2603,29 @@ addr_of_non_const_var (tree *tp, int *walk_subtrees, void *data) static tree cxx_bind_parameters_in_call (const constexpr_ctx *ctx, tree t, tree fun, - bool *non_constant_p, bool *overflow_p, - bool *non_constant_args) + tree orig_fun, bool *non_constant_p, + bool *overflow_p, bool *non_constant_args, + tree *jump_target) { - const int nargs = call_expr_nargs (t); + int nargs = call_expr_nargs (t); tree parms = DECL_ARGUMENTS (fun); - int i; + int i, j = 0; + if (DECL_HAS_IN_CHARGE_PARM_P (fun) && fun != orig_fun) + ++nargs; + if (DECL_HAS_VTT_PARM_P (fun) + && fun != orig_fun + && (DECL_COMPLETE_CONSTRUCTOR_P (orig_fun) + || DECL_COMPLETE_DESTRUCTOR_P (orig_fun))) + ++nargs; /* We don't record ellipsis args below. */ int nparms = list_length (parms); int nbinds = nargs < nparms ? nargs : nparms; tree binds = make_tree_vec (nbinds); /* The call is not a constant expression if it involves the cdtor for a type - with virtual bases. */ - if (DECL_HAS_IN_CHARGE_PARM_P (fun) || DECL_HAS_VTT_PARM_P (fun)) + with virtual bases before C++26. */ + if (cxx_dialect < cxx26 + && (DECL_HAS_IN_CHARGE_PARM_P (fun) || DECL_HAS_VTT_PARM_P (fun))) { if (!ctx->quiet) { @@ -1885,7 +2643,30 @@ cxx_bind_parameters_in_call (const constexpr_ctx *ctx, tree t, tree fun, tree type = parms ? TREE_TYPE (parms) : void_type_node; if (parms && DECL_BY_REFERENCE (parms)) type = TREE_TYPE (type); - x = get_nth_callarg (t, i); + if (i == 1 + && j == 0 + && DECL_HAS_IN_CHARGE_PARM_P (fun) + && orig_fun != fun) + { + if (DECL_COMPLETE_CONSTRUCTOR_P (orig_fun) + || DECL_COMPLETE_DESTRUCTOR_P (orig_fun)) + x = boolean_true_node; + else + x = boolean_false_node; + j = -1; + } + else if (i == 2 + && j == -1 + && DECL_HAS_VTT_PARM_P (fun) + && orig_fun != fun + && (DECL_COMPLETE_CONSTRUCTOR_P (orig_fun) + || DECL_COMPLETE_DESTRUCTOR_P (orig_fun))) + { + x = build_zero_cst (type); + j = -2; + } + else + x = get_nth_callarg (t, i + j); /* For member function, the first argument is a pointer to the implied object. For a constructor, it might still be a dummy object, in which case we get the real argument from ctx. */ @@ -1900,14 +2681,16 @@ cxx_bind_parameters_in_call (const constexpr_ctx *ctx, tree t, tree fun, /* Undo convert_for_arg_passing work here. */ x = convert_from_reference (x); arg = cxx_eval_constant_expression (ctx, x, vc_glvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); } else /* Normally we would strip a TARGET_EXPR in an initialization context such as this, but here we do the elision differently: we keep the TARGET_EXPR, and use its CONSTRUCTOR as the value of the parm. */ arg = cxx_eval_constant_expression (ctx, x, vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); /* Check we aren't dereferencing a null pointer when calling a non-static member function, which is undefined behaviour. */ if (i == 0 && DECL_OBJECT_MEMBER_FUNCTION_P (fun) @@ -1925,6 +2708,8 @@ cxx_bind_parameters_in_call (const constexpr_ctx *ctx, tree t, tree fun, /* Don't VERIFY_CONSTANT here. */ if (*non_constant_p && ctx->quiet) break; + if (*jump_target) + break; /* Just discard ellipsis args after checking their constantitude. */ if (!parms) continue; @@ -2036,9 +2821,10 @@ fold_operand (tree e, const constexpr_ctx *ctx) if (ctx) { bool new_non_constant_p = false, new_overflow_p = false; + tree jmp_target = NULL_TREE; e = cxx_eval_constant_expression (ctx, e, vc_prvalue, &new_non_constant_p, - &new_overflow_p); + &new_overflow_p, &jmp_target); } else e = fold_non_dependent_expr (e, tf_none, /*manifestly_const_eval=*/true); @@ -2125,7 +2911,7 @@ cxx_eval_assert (const constexpr_ctx *ctx, tree arg, const char *msg, if (*non_constant_p) return true; - tree eval; + tree eval, jmp_target = NULL_TREE; if (!evaluated) { if (!potential_rvalue_constant_expression (arg)) @@ -2138,12 +2924,15 @@ cxx_eval_assert (const constexpr_ctx *ctx, tree arg, const char *msg, modifiable_tracker ms (new_ctx.global); eval = cxx_eval_constant_expression (&new_ctx, arg, vc_prvalue, &new_non_constant_p, - &new_overflow_p); + &new_overflow_p, &jmp_target); } else eval = cxx_eval_constant_expression (ctx, arg, vc_prvalue, non_constant_p, - overflow_p); + overflow_p, &jmp_target); + if (jmp_target) + return true; + if (!*non_constant_p && integer_zerop (eval)) { if (!ctx->quiet) @@ -2175,7 +2964,8 @@ cxx_eval_assert (const constexpr_ctx *ctx, tree arg, const char *msg, static tree cxx_eval_internal_function (const constexpr_ctx *ctx, tree t, value_cat lval, - bool *non_constant_p, bool *overflow_p) + bool *non_constant_p, bool *overflow_p, + tree *jump_target) { enum tree_code opcode = ERROR_MARK; @@ -2208,13 +2998,15 @@ cxx_eval_internal_function (const constexpr_ctx *ctx, tree t, case IFN_LAUNDER: return cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 0), vc_prvalue, non_constant_p, - overflow_p); + overflow_p, jump_target); case IFN_VEC_CONVERT: { tree arg = cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 0), vc_prvalue, non_constant_p, - overflow_p); + overflow_p, jump_target); + if (*jump_target) + return NULL_TREE; if (TREE_CODE (arg) == VECTOR_CST) if (tree r = fold_const_call (CFN_VEC_CONVERT, TREE_TYPE (t), arg)) return r; @@ -2232,10 +3024,13 @@ cxx_eval_internal_function (const constexpr_ctx *ctx, tree t, /* Evaluate constant arguments using OPCODE and return a complex number containing the result and the overflow bit. */ tree arg0 = cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 0), lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); tree arg1 = cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 1), lval, - non_constant_p, overflow_p); - + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST) { location_t loc = cp_expr_loc_or_input_loc (t); @@ -2504,14 +3299,12 @@ get_component_with_type (tree path, tree type, tree stop) dst_ptr + src2dst == src_ptr -1: unspecified relationship -2: src_type is not a public base of dst_type - -3: src_type is a multiple public non-virtual base of dst_type - - Since literal types can't have virtual bases, we only expect hint >=0, - -2, or -3. */ + -3: src_type is a multiple public non-virtual base of dst_type */ static tree cxx_eval_dynamic_cast_fn (const constexpr_ctx *ctx, tree call, - bool *non_constant_p, bool *overflow_p) + bool *non_constant_p, bool *overflow_p, + tree *jump_target) { /* T will be something like __dynamic_cast ((B*) b, &_ZTI1B, &_ZTI1D, 8) @@ -2530,19 +3323,42 @@ cxx_eval_dynamic_cast_fn (const constexpr_ctx *ctx, tree call, /* TYPE can only be either T* or T&. We can't know which of these it is by looking at TYPE, but OBJ will be "(T*) x" in the first case, - and something like "(T*)(T&)(T*) x" in the second case. */ - bool reference_p = false; + and something like "(T*)(T&)(T*) x" in the second case. + This is true for the reference cases in C++ < 26 or when exceptions + aren't enabled, in that case we should diagnose errors. For C++26 + with exceptions we should silently evaluate to null pointer and + let the callers call __cxa_bad_cast () later to throw an exception. */ + bool fail_for_non_constant_p = false; while (CONVERT_EXPR_P (obj) || TREE_CODE (obj) == SAVE_EXPR) { - reference_p |= TYPE_REF_P (TREE_TYPE (obj)); + if (cxx_dialect < cxx26 || !flag_exceptions) + fail_for_non_constant_p |= TYPE_REF_P (TREE_TYPE (obj)); obj = TREE_OPERAND (obj, 0); } /* Evaluate the object so that we know its dynamic type. */ obj = cxx_eval_constant_expression (ctx, obj, vc_prvalue, non_constant_p, - overflow_p); + overflow_p, jump_target); if (*non_constant_p) return call; + if (*jump_target) + return NULL_TREE; + + /* For dynamic_cast from classes with virtual bases we can get something + like (virt_base *)(&d + 16) as OBJ. Try to convert that into + d.D.1234 using cxx_fold_indirect_ref. */ + if (cxx_dialect >= cxx26 && CONVERT_EXPR_P (obj)) + { + tree objo = obj; + STRIP_NOPS (objo); + if (TREE_CODE (objo) == POINTER_PLUS_EXPR) + { + objo = cxx_fold_indirect_ref (ctx, loc, TREE_TYPE (TREE_TYPE (obj)), + obj, NULL, jump_target); + if (objo) + obj = build_fold_addr_expr (objo); + } + } /* We expect OBJ to be in form of &d.D.2102 when HINT == 0, but when HINT is > 0, it can also be something like @@ -2554,7 +3370,7 @@ cxx_eval_dynamic_cast_fn (const constexpr_ctx *ctx, tree call, ? TREE_OPERAND (obj, 1) : obj)) if (TREE_CODE (t) != FIELD_DECL || !DECL_FIELD_IS_BASE (t)) { - if (reference_p) + if (fail_for_non_constant_p) { if (!ctx->quiet) { @@ -2576,9 +3392,12 @@ cxx_eval_dynamic_cast_fn (const constexpr_ctx *ctx, tree call, constructor or destructor's class. */ tree vtable = build_vfield_ref (obj, objtype); vtable = cxx_eval_constant_expression (ctx, vtable, vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); if (*non_constant_p) return call; + if (*jump_target) + return NULL_TREE; /* With -fsanitize=vptr, we initialize all vtable pointers to null, so it's possible that we got a null pointer now. */ if (integer_zerop (vtable)) @@ -2610,7 +3429,7 @@ cxx_eval_dynamic_cast_fn (const constexpr_ctx *ctx, tree call, /* If not accessible, give an error. */ if (t == error_mark_node) { - if (reference_p) + if (fail_for_non_constant_p) { if (!ctx->quiet) { @@ -2643,7 +3462,7 @@ cxx_eval_dynamic_cast_fn (const constexpr_ctx *ctx, tree call, obj = get_component_with_type (obj, mdtype, NULL_TREE); if (obj == error_mark_node) { - if (reference_p) + if (fail_for_non_constant_p) { if (!ctx->quiet) { @@ -2665,7 +3484,7 @@ cxx_eval_dynamic_cast_fn (const constexpr_ctx *ctx, tree call, tree binfo = lookup_base (mdtype, type, ba_check, &b_kind, tf_none); if (!binfo || binfo == error_mark_node) { - if (reference_p) + if (fail_for_non_constant_p) { if (!ctx->quiet) { @@ -2761,7 +3580,7 @@ replace_decl (tree *tp, tree decl, tree replacement) static tree cxx_eval_thunk_call (const constexpr_ctx *ctx, tree t, tree thunk_fndecl, value_cat lval, - bool *non_constant_p, bool *overflow_p) + bool *non_constant_p, bool *overflow_p, tree *jump_target) { tree function = THUNK_TARGET (thunk_fndecl); @@ -2804,7 +3623,8 @@ cxx_eval_thunk_call (const constexpr_ctx *ctx, tree t, tree thunk_fndecl, new_call, offset); return cxx_eval_constant_expression (ctx, new_call, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); } /* If OBJECT is of const class type, evaluate it to a CONSTRUCTOR and set @@ -2814,7 +3634,7 @@ cxx_eval_thunk_call (const constexpr_ctx *ctx, tree t, tree thunk_fndecl, static void cxx_set_object_constness (const constexpr_ctx *ctx, tree object, bool readonly_p, bool *non_constant_p, - bool *overflow_p) + bool *overflow_p, tree *jump_target) { if (CLASS_TYPE_P (TREE_TYPE (object)) && CP_TYPE_CONST_P (TREE_TYPE (object))) @@ -2822,8 +3642,11 @@ cxx_set_object_constness (const constexpr_ctx *ctx, tree object, /* Subobjects might not be stored in ctx->global->values but we can get its CONSTRUCTOR by evaluating *this. */ tree e = cxx_eval_constant_expression (ctx, object, vc_prvalue, - non_constant_p, overflow_p); - if (TREE_CODE (e) == CONSTRUCTOR && !*non_constant_p) + non_constant_p, overflow_p, + jump_target); + if (!*non_constant_p + && !throws (jump_target) + && TREE_CODE (e) == CONSTRUCTOR) TREE_READONLY (e) = readonly_p; } } @@ -2835,23 +3658,25 @@ cxx_set_object_constness (const constexpr_ctx *ctx, tree object, static tree cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, value_cat lval, - bool *non_constant_p, bool *overflow_p) + bool *non_constant_p, bool *overflow_p, + tree *jump_target) { location_t loc = cp_expr_loc_or_input_loc (t); tree fun = get_function_named_in_call (t); - constexpr_call new_call - = { NULL, NULL, NULL, 0, ctx->manifestly_const_eval }; - int depth_ok; if (fun == NULL_TREE) return cxx_eval_internal_function (ctx, t, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); if (TREE_CODE (fun) != FUNCTION_DECL) { /* Might be a constexpr function pointer. */ fun = cxx_eval_constant_expression (ctx, fun, vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; STRIP_NOPS (fun); if (TREE_CODE (fun) == ADDR_EXPR) fun = TREE_OPERAND (fun, 0); @@ -2894,6 +3719,7 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, *non_constant_p = true; return t; } + tree orig_fun = fun; if (DECL_CLONED_FUNCTION_P (fun) && !DECL_DELETING_DESTRUCTOR_P (fun)) fun = DECL_CLONED_FUNCTION (fun); @@ -2902,9 +3728,12 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, if (fndecl_built_in_p (fun)) return cxx_eval_builtin_function_call (ctx, t, fun, - lval, non_constant_p, overflow_p); + lval, non_constant_p, overflow_p, + jump_target); if (DECL_THUNK_P (fun)) - return cxx_eval_thunk_call (ctx, t, fun, lval, non_constant_p, overflow_p); + return cxx_eval_thunk_call (ctx, t, fun, lval, non_constant_p, overflow_p, + jump_target); + bool non_constexpr_call = false; if (!maybe_constexpr_fn (fun)) { if (TREE_CODE (t) == CALL_EXPR @@ -2919,7 +3748,10 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, { tree arg = CALL_EXPR_ARG (t, i); arg = cxx_eval_constant_expression (ctx, arg, vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; /* Deleting a non-constant pointer has a better error message below. */ if (new_op_p || i != 0) @@ -2930,12 +3762,11 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, gcc_assert (arg0); if (new_op_p) { - /* FIXME: We should not get here; the VERIFY_CONSTANT above - should have already caught it. But currently a conversion - from pointer type to arithmetic type is only considered - non-constant for CONVERT_EXPRs, not NOP_EXPRs. */ if (!tree_fits_uhwi_p (arg0)) { + /* We should not get here; the VERIFY_CONSTANT above + should have already caught it. */ + gcc_checking_assert (false); if (!ctx->quiet) error_at (loc, "cannot allocate array: size not constant"); *non_constant_p = true; @@ -2950,14 +3781,6 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, : heap_uninit_identifier, type); DECL_ARTIFICIAL (var) = 1; - TREE_STATIC (var) = 1; - // Temporarily register the artificial var in varpool, - // so that comparisons of its address against NULL are folded - // through nonzero_address even with - // -fno-delete-null-pointer-checks or that comparison of - // addresses of different heap artificial vars is folded too. - // See PR98988 and PR99031. - varpool_node::finalize_decl (var); ctx->global->heap_vars.safe_push (var); ctx->global->put_value (var, NULL_TREE); return fold_convert (ptr_type_node, build_address (var)); @@ -3043,7 +3866,10 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, { tree arg = CALL_EXPR_ARG (t, i); arg = cxx_eval_constant_expression (ctx, arg, vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; if (i == 1) arg1 = arg; else @@ -3053,19 +3879,35 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, return arg1; } else if (cxx_dynamic_cast_fn_p (fun)) - return cxx_eval_dynamic_cast_fn (ctx, t, non_constant_p, overflow_p); + return cxx_eval_dynamic_cast_fn (ctx, t, non_constant_p, overflow_p, + jump_target); + else if (enum cxa_builtin kind = cxx_cxa_builtin_fn_p (fun)) + return cxx_eval_cxa_builtin_fn (ctx, t, kind, fun, + non_constant_p, overflow_p, + jump_target); - if (!ctx->quiet) + /* Calls to non-constexpr functions can be diagnosed right away + before C++26, though in C++26 evaluation of the arguments might + throw and if caught it could be still constant expression. + So for C++26 this is diagnosed only after + cxx_bind_parameters_in_call. */ + if (cxx_dialect >= cxx26) + non_constexpr_call = true; + else { - if (!lambda_static_thunk_p (fun)) - error_at (loc, "call to non-%<constexpr%> function %qD", fun); - explain_invalid_constexpr_fn (fun); + if (!ctx->quiet) + { + if (!lambda_static_thunk_p (fun)) + error_at (loc, "call to non-%<constexpr%> function %qD", fun); + explain_invalid_constexpr_fn (fun); + } + *non_constant_p = true; + return t; } - *non_constant_p = true; - return t; } constexpr_ctx new_ctx = *ctx; + ctx = &new_ctx; if (DECL_CONSTRUCTOR_P (fun) && !ctx->object && TREE_CODE (t) == AGGR_INIT_EXPR) { @@ -3075,30 +3917,30 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, tree ctor = new_ctx.ctor = build_constructor (DECL_CONTEXT (fun), NULL); CONSTRUCTOR_NO_CLEARING (ctor) = true; ctx->global->put_value (new_ctx.object, ctor); - ctx = &new_ctx; } /* An immediate invocation is manifestly constant evaluated including the arguments of the call, so use mce_true even for the argument evaluation. */ if (DECL_IMMEDIATE_FUNCTION_P (fun)) - { - new_ctx.manifestly_const_eval = mce_true; - new_call.manifestly_const_eval = mce_true; - ctx = &new_ctx; - } + new_ctx.manifestly_const_eval = mce_true; /* We used to shortcut trivial constructor/op= here, but nowadays we can only get a trivial function here with -fno-elide-constructors. */ gcc_checking_assert (!trivial_fn_p (fun) || !flag_elide_constructors + /* Or it's a call from maybe_thunk_body (111075). */ + || (TREE_CODE (t) == CALL_EXPR ? CALL_FROM_THUNK_P (t) + : AGGR_INIT_FROM_THUNK_P (t)) /* We don't elide constructors when processing a noexcept-expression. */ || cp_noexcept_operand); bool non_constant_args = false; + constexpr_call new_call; new_call.bindings - = cxx_bind_parameters_in_call (ctx, t, fun, non_constant_p, - overflow_p, &non_constant_args); + = cxx_bind_parameters_in_call (ctx, t, fun, orig_fun, non_constant_p, + overflow_p, &non_constant_args, + jump_target); /* We build up the bindings list before we know whether we already have this call cached. If we don't end up saving these bindings, ggc_free them when @@ -3112,8 +3954,21 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, void preserve () { bindings = NULL; } } fb (new_call.bindings); + if (*jump_target) + return NULL_TREE; if (*non_constant_p) return t; + if (non_constexpr_call) + { + if (!ctx->quiet) + { + if (!lambda_static_thunk_p (fun)) + error_at (loc, "call to non-%<constexpr%> function %qD", fun); + explain_invalid_constexpr_fn (fun); + } + *non_constant_p = true; + return t; + } /* We can't defer instantiating the function any longer. */ if (!DECL_INITIAL (fun) @@ -3169,7 +4024,12 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, } } - depth_ok = push_cx_call_context (t); + /* Don't complain about problems evaluating an ill-formed function. */ + if (function *f = DECL_STRUCT_FUNCTION (fun)) + if (f->language->erroneous) + new_ctx.quiet = true; + + int depth_ok = push_cx_call_context (t); /* Remember the object we are constructing or destructing. */ tree new_obj = NULL_TREE; @@ -3181,7 +4041,9 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, new_obj = TREE_VEC_ELT (new_call.bindings, 0); bool empty_base = false; new_obj = cxx_fold_indirect_ref (ctx, loc, DECL_CONTEXT (fun), new_obj, - &empty_base); + &empty_base, jump_target); + if (*jump_target) + return NULL_TREE; /* If we're initializing an empty class, don't set constness, because cxx_fold_indirect_ref will return the wrong object to set constness of. */ @@ -3211,8 +4073,6 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, new_call.hash = constexpr_fundef_hasher::hash (new_call.fundef); new_call.hash = iterative_hash_template_arg (new_call.bindings, new_call.hash); - new_call.hash - = iterative_hash_object (ctx->manifestly_const_eval, new_call.hash); /* If we have seen this call before, we are done. */ maybe_initialize_constexpr_call_table (); @@ -3230,22 +4090,23 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, the slot can move during evaluation of the body. */ *slot = entry = ggc_alloc<constexpr_call> (); *entry = new_call; + entry->result (ctx->manifestly_const_eval) = unknown_type_node; fb.preserve (); } } - /* Calls that are in progress have their result set to NULL, so that we - can detect circular dependencies. Now that we only cache up to - constexpr_cache_depth this won't catch circular dependencies that + /* Calls that are in progress have their result set to unknown_type_node, + so that we can detect circular dependencies. Now that we only cache + up to constexpr_cache_depth this won't catch circular dependencies that start deeper, but they'll hit the recursion or ops limit. */ - else if (entry->result == NULL) + else if (entry->result (ctx->manifestly_const_eval) == unknown_type_node) { if (!ctx->quiet) error ("call has circular dependency"); *non_constant_p = true; - entry->result = result = error_mark_node; + entry->result (ctx->manifestly_const_eval) = result = error_mark_node; } else - result = entry->result; + result = entry->result (ctx->manifestly_const_eval); } if (!depth_ok) @@ -3331,7 +4192,7 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, semantics are no longer in effect; see [class.dtor]p5. */ if (new_obj && DECL_DESTRUCTOR_P (fun)) cxx_set_object_constness (ctx, new_obj, /*readonly_p=*/false, - non_constant_p, overflow_p); + non_constant_p, overflow_p, jump_target); /* If this is a constructor, we are beginning the lifetime of the object we are initializing. */ @@ -3345,16 +4206,25 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, build_constructor (TREE_TYPE (new_obj), NULL)); cxx_eval_constant_expression (ctx, activate, - lval, non_constant_p, overflow_p); + lval, non_constant_p, overflow_p, + jump_target); ggc_free (activate); + if (*jump_target) + return NULL_TREE; } - tree jump_target = NULL_TREE; + tree jmp_target = NULL_TREE; cxx_eval_constant_expression (&call_ctx, body, vc_discard, non_constant_p, overflow_p, - &jump_target); + &jmp_target); - if (DECL_CONSTRUCTOR_P (fun)) + if (!*non_constant_p && throws (&jmp_target)) + { + result = NULL_TREE; + cacheable = false; + *jump_target = jmp_target; + } + else if (DECL_CONSTRUCTOR_P (fun)) /* This can be null for a subobject constructor call, in which case what we care about is the initialization side-effects rather than the value. We could get at the @@ -3382,7 +4252,7 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, marking the CONSTRUCTOR TREE_READONLY. */ if (new_obj && DECL_CONSTRUCTOR_P (fun)) cxx_set_object_constness (ctx, new_obj, /*readonly_p=*/true, - non_constant_p, overflow_p); + non_constant_p, overflow_p, jump_target); /* Remove the parms/result from the values map. */ destroy_value_checked (ctx, res, non_constant_p); @@ -3425,11 +4295,6 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, cacheable = false; break; } - /* And don't cache a ref to a deleted heap variable (119162). */ - if (cacheable - && (cp_walk_tree_without_duplicates - (&result, find_deleted_heap_var, NULL))) - cacheable = false; } /* Rewrite all occurrences of the function's RESULT_DECL with the @@ -3447,7 +4312,13 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, cacheable = false; result = cxx_eval_constant_expression (ctx, result, lval, non_constant_p, - overflow_p); + overflow_p, + jump_target); + if (*jump_target) + { + cacheable = false; + result = NULL_TREE; + } } } @@ -3466,7 +4337,22 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, else if (!result) result = void_node; if (entry) - entry->result = cacheable ? result : error_mark_node; + { + entry->result (ctx->manifestly_const_eval) + = cacheable ? result : error_mark_node; + + if (result != error_mark_node + && ctx->manifestly_const_eval == mce_unknown) + { + /* Evaluation succeeded and was independent of whether we're in a + manifestly constant-evaluated context, so we can also reuse + this result when evaluating this call with a fixed context. */ + if (!entry->result (mce_true)) + entry->result (mce_true) = entry->result (mce_unknown); + if (!entry->result (mce_false)) + entry->result (mce_false) = entry->result (mce_unknown); + } + } } /* The result of a constexpr function must be completely initialized. @@ -3487,11 +4373,12 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, /* Return true if T is a valid constant initializer. If a CONSTRUCTOR initializes all the members, the CONSTRUCTOR_NO_CLEARING flag will be - cleared. + cleared. If called recursively on a FIELD_DECL's CONSTRUCTOR, SZ + is DECL_SIZE of the FIELD_DECL, otherwise NULL. FIXME speed this up, it's taking 16% of compile time on sieve testcase. */ bool -reduced_constant_expression_p (tree t) +reduced_constant_expression_p (tree t, tree sz /* = NULL_TREE */) { if (t == NULL_TREE) return false; @@ -3502,6 +4389,9 @@ reduced_constant_expression_p (tree t) /* Even if we can't lower this yet, it's constant. */ return true; + case OMP_DECLARE_MAPPER: + return true; + case CONSTRUCTOR: /* And we need to handle PTRMEM_CST wrapped in a CONSTRUCTOR. */ tree field; @@ -3556,7 +4446,12 @@ reduced_constant_expression_p (tree t) { /* If VAL is null, we're in the middle of initializing this element. */ - if (!reduced_constant_expression_p (e.value)) + if (!reduced_constant_expression_p (e.value, + (e.index + && (TREE_CODE (e.index) + == FIELD_DECL)) + ? DECL_SIZE (e.index) + : NULL_TREE)) return false; /* We want to remove initializers for empty fields in a struct to avoid confusing output_constructor. */ @@ -3576,7 +4471,16 @@ reduced_constant_expression_p (tree t) /* There could be a non-empty field at the end. */ for (; field; field = next_subobject_field (DECL_CHAIN (field))) if (!is_really_empty_class (TREE_TYPE (field), /*ignore_vptr*/false)) - return false; + { + /* Ignore FIELD_DECLs with bit positions beyond DECL_SIZE of + the parent FIELD_DECL (if any) for classes with virtual + bases. */ + if (cxx_dialect >= cxx26 + && sz + && tree_int_cst_le (sz, bit_position (field))) + break; + return false; + } ok: if (CONSTRUCTOR_NO_CLEARING (t)) /* All the fields are initialized. */ @@ -3772,12 +4676,16 @@ cxx_eval_check_shift_p (location_t loc, const constexpr_ctx *ctx, static tree cxx_eval_unary_expression (const constexpr_ctx *ctx, tree t, bool /*lval*/, - bool *non_constant_p, bool *overflow_p) + bool *non_constant_p, bool *overflow_p, + tree *jump_target) { tree r; tree orig_arg = TREE_OPERAND (t, 0); tree arg = cxx_eval_constant_expression (ctx, orig_arg, vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; VERIFY_CONSTANT (arg); location_t loc = EXPR_LOCATION (t); enum tree_code code = TREE_CODE (t); @@ -3801,7 +4709,7 @@ cxx_eval_unary_expression (const constexpr_ctx *ctx, tree t, static tree cxx_fold_pointer_plus_expression (const constexpr_ctx *ctx, tree t, tree lhs, tree rhs, bool *non_constant_p, - bool *overflow_p) + bool *overflow_p, tree *jump_target) { STRIP_NOPS (lhs); if (TREE_CODE (lhs) != ADDR_EXPR) @@ -3823,9 +4731,12 @@ cxx_fold_pointer_plus_expression (const constexpr_ctx *ctx, tree t, t = fold_convert_loc (loc, ssizetype, TREE_OPERAND (lhs, 1)); tree nelts = array_type_nelts_top (TREE_TYPE (TREE_OPERAND (lhs, 0))); nelts = cxx_eval_constant_expression (ctx, nelts, vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); if (*non_constant_p) return NULL_TREE; + if (*jump_target) + return NULL_TREE; /* Don't fold an out-of-bound access. */ if (!tree_int_cst_le (t, nelts)) return NULL_TREE; @@ -3845,7 +4756,8 @@ cxx_fold_pointer_plus_expression (const constexpr_ctx *ctx, tree t, t = cp_build_addr_expr (t, tf_warning_or_error); t = cp_fold_convert (orig_type, t); return cxx_eval_constant_expression (ctx, t, vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); } return NULL_TREE; @@ -3889,22 +4801,29 @@ cxx_maybe_fold_addr_pointer_plus (tree t) static tree cxx_eval_binary_expression (const constexpr_ctx *ctx, tree t, value_cat lval, - bool *non_constant_p, bool *overflow_p) + bool *non_constant_p, bool *overflow_p, + tree *jump_target) { tree r = NULL_TREE; tree orig_lhs = TREE_OPERAND (t, 0); tree orig_rhs = TREE_OPERAND (t, 1); tree lhs, rhs; lhs = cxx_eval_constant_expression (ctx, orig_lhs, vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); /* Don't VERIFY_CONSTANT here, it's unnecessary and will break pointer subtraction. */ if (*non_constant_p) return t; + if (*jump_target) + return NULL_TREE; rhs = cxx_eval_constant_expression (ctx, orig_rhs, vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); if (*non_constant_p) return t; + if (*jump_target) + return NULL_TREE; location_t loc = EXPR_LOCATION (t); enum tree_code code = TREE_CODE (t); @@ -3960,13 +4879,17 @@ cxx_eval_binary_expression (const constexpr_ctx *ctx, tree t, return t; } else if (code == POINTER_PLUS_EXPR) - r = cxx_fold_pointer_plus_expression (ctx, t, lhs, rhs, non_constant_p, - overflow_p); + { + r = cxx_fold_pointer_plus_expression (ctx, t, lhs, rhs, non_constant_p, + overflow_p, jump_target); + if (*jump_target) + return NULL_TREE; + } else if (code == SPACESHIP_EXPR) { r = genericize_spaceship (loc, type, lhs, rhs); return cxx_eval_constant_expression (ctx, r, lval, non_constant_p, - overflow_p); + overflow_p, jump_target); } if (r == NULL_TREE) @@ -4025,7 +4948,10 @@ cxx_eval_conditional_expression (const constexpr_ctx *ctx, tree t, { tree val = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; VERIFY_CONSTANT (val); if (TREE_CODE (t) == IF_STMT && IF_STMT_CONSTEVAL_P (t)) { @@ -4086,19 +5012,29 @@ cxx_eval_conditional_expression (const constexpr_ctx *ctx, tree t, static tree cxx_eval_vector_conditional_expression (const constexpr_ctx *ctx, tree t, - bool *non_constant_p, bool *overflow_p) + bool *non_constant_p, bool *overflow_p, + tree *jump_target) { tree arg1 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; VERIFY_CONSTANT (arg1); tree arg2 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; VERIFY_CONSTANT (arg2); tree arg3 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; VERIFY_CONSTANT (arg3); location_t loc = EXPR_LOCATION (t); tree type = TREE_TYPE (t); @@ -4486,7 +5422,8 @@ diag_array_subscript (location_t loc, const constexpr_ctx *ctx, tree array, tree static tree get_array_or_vector_nelts (const constexpr_ctx *ctx, tree type, - bool *non_constant_p, bool *overflow_p) + bool *non_constant_p, bool *overflow_p, + tree *jump_target) { tree nelts; if (TREE_CODE (type) == ARRAY_TYPE) @@ -4503,7 +5440,8 @@ get_array_or_vector_nelts (const constexpr_ctx *ctx, tree type, /* For VLAs, the number of elements won't be an integer constant. */ nelts = cxx_eval_constant_expression (ctx, nelts, vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); return nelts; } @@ -4534,13 +5472,17 @@ extract_string_elt (tree string, unsigned chars_per_elt, unsigned index) static tree eval_and_check_array_index (const constexpr_ctx *ctx, tree t, bool allow_one_past, - bool *non_constant_p, bool *overflow_p) + bool *non_constant_p, bool *overflow_p, + tree *jump_target) { location_t loc = cp_expr_loc_or_input_loc (t); tree ary = TREE_OPERAND (t, 0); t = TREE_OPERAND (t, 1); tree index = cxx_eval_constant_expression (ctx, t, vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; VERIFY_CONSTANT (index); if (!tree_fits_shwi_p (index) @@ -4552,7 +5494,9 @@ eval_and_check_array_index (const constexpr_ctx *ctx, } tree nelts = get_array_or_vector_nelts (ctx, TREE_TYPE (ary), non_constant_p, - overflow_p); + overflow_p, jump_target); + if (*jump_target) + return NULL_TREE; VERIFY_CONSTANT (nelts); if (allow_one_past ? !tree_int_cst_le (index, nelts) @@ -4572,14 +5516,18 @@ eval_and_check_array_index (const constexpr_ctx *ctx, static tree cxx_eval_array_reference (const constexpr_ctx *ctx, tree t, value_cat lval, - bool *non_constant_p, bool *overflow_p) + bool *non_constant_p, bool *overflow_p, + tree *jump_target) { tree oldary = TREE_OPERAND (t, 0); tree ary = cxx_eval_constant_expression (ctx, oldary, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); if (*non_constant_p) return t; + if (*jump_target) + return NULL_TREE; if (!lval && TREE_CODE (ary) == VIEW_CONVERT_EXPR && VECTOR_TYPE_P (TREE_TYPE (TREE_OPERAND (ary, 0))) @@ -4589,9 +5537,12 @@ cxx_eval_array_reference (const constexpr_ctx *ctx, tree t, tree oldidx = TREE_OPERAND (t, 1); tree index = eval_and_check_array_index (ctx, t, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); if (*non_constant_p) return t; + if (*jump_target) + return NULL_TREE; if (lval && ary == oldary && index == oldidx) return t; @@ -4709,7 +5660,7 @@ cxx_eval_array_reference (const constexpr_ctx *ctx, tree t, ctx = &new_ctx; } t = cxx_eval_constant_expression (ctx, val, lval, non_constant_p, - overflow_p); + overflow_p, jump_target); if (new_ctor && t != ctx->ctor) free_constructor (ctx->ctor); return t; @@ -4721,7 +5672,8 @@ cxx_eval_array_reference (const constexpr_ctx *ctx, tree t, static tree cxx_eval_component_reference (const constexpr_ctx *ctx, tree t, value_cat lval, - bool *non_constant_p, bool *overflow_p) + bool *non_constant_p, bool *overflow_p, + tree *jump_target) { unsigned HOST_WIDE_INT i; tree field; @@ -4730,9 +5682,12 @@ cxx_eval_component_reference (const constexpr_ctx *ctx, tree t, tree orig_whole = TREE_OPERAND (t, 0); tree whole = cxx_eval_constant_expression (ctx, orig_whole, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); if (*non_constant_p) return t; + if (*jump_target) + return NULL_TREE; if (INDIRECT_REF_P (whole) && integer_zerop (TREE_OPERAND (whole, 0))) { @@ -4841,7 +5796,8 @@ cxx_eval_component_reference (const constexpr_ctx *ctx, tree t, value = build_value_init (TREE_TYPE (t), tf_warning_or_error); return cxx_eval_constant_expression (ctx, value, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); } /* Subroutine of cxx_eval_constant_expression. @@ -4851,7 +5807,8 @@ cxx_eval_component_reference (const constexpr_ctx *ctx, tree t, static tree cxx_eval_bit_field_ref (const constexpr_ctx *ctx, tree t, value_cat lval, - bool *non_constant_p, bool *overflow_p) + bool *non_constant_p, bool *overflow_p, + tree *jump_target) { tree orig_whole = TREE_OPERAND (t, 0); tree retval, fldval, utype, mask; @@ -4859,10 +5816,13 @@ cxx_eval_bit_field_ref (const constexpr_ctx *ctx, tree t, HOST_WIDE_INT istart, isize; tree whole = cxx_eval_constant_expression (ctx, orig_whole, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); tree start, field, value; unsigned HOST_WIDE_INT i; + if (*jump_target) + return NULL_TREE; if (whole == orig_whole) return t; /* Don't VERIFY_CONSTANT here; we only want to check that we got a @@ -5143,7 +6103,7 @@ clear_uchar_or_std_byte_in_mask (location_t loc, tree t, unsigned char *mask) static tree cxx_eval_bit_cast (const constexpr_ctx *ctx, tree t, bool *non_constant_p, - bool *overflow_p) + bool *overflow_p, tree *jump_target) { if (check_bit_cast_type (ctx, EXPR_LOCATION (t), TREE_TYPE (t), TREE_TYPE (t)) @@ -5157,9 +6117,12 @@ cxx_eval_bit_cast (const constexpr_ctx *ctx, tree t, bool *non_constant_p, } tree op = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); if (*non_constant_p) return t; + if (*jump_target) + return NULL_TREE; location_t loc = EXPR_LOCATION (t); if (BITS_PER_UNIT != 8 || CHAR_BIT != 8) @@ -5237,8 +6200,9 @@ cxx_eval_bit_cast (const constexpr_ctx *ctx, tree t, bool *non_constant_p, if (CHECKING_P) { tree e = cxx_eval_bare_aggregate (ctx, r, vc_prvalue, - non_constant_p, overflow_p); - gcc_checking_assert (e == r); + non_constant_p, overflow_p, + jump_target); + gcc_checking_assert (e == r && !*jump_target); r = e; } } @@ -5279,19 +6243,24 @@ cxx_eval_bit_cast (const constexpr_ctx *ctx, tree t, bool *non_constant_p, static tree cxx_eval_logical_expression (const constexpr_ctx *ctx, tree t, tree bailout_value, tree continue_value, - bool *non_constant_p, bool *overflow_p) + bool *non_constant_p, bool *overflow_p, + tree *jump_target) { tree r; tree lhs = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), vc_prvalue, non_constant_p, - overflow_p); + overflow_p, jump_target); + if (*jump_target) + return NULL_TREE; VERIFY_CONSTANT (lhs); if (tree_int_cst_equal (lhs, bailout_value)) return lhs; gcc_assert (tree_int_cst_equal (lhs, continue_value)); r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), vc_prvalue, non_constant_p, - overflow_p); + overflow_p, jump_target); + if (*jump_target) + return NULL_TREE; VERIFY_CONSTANT (r); return r; } @@ -5448,7 +6417,8 @@ verify_ctor_sanity (const constexpr_ctx *ctx, tree type) static tree cxx_eval_bare_aggregate (const constexpr_ctx *ctx, tree t, value_cat lval, - bool *non_constant_p, bool *overflow_p) + bool *non_constant_p, bool *overflow_p, + tree *jump_target) { vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); bool changed = false; @@ -5501,7 +6471,10 @@ cxx_eval_bare_aggregate (const constexpr_ctx *ctx, tree t, get_or_insert_ctor_field (ctx->ctor, index); tree elt = cxx_eval_constant_expression (&new_ctx, value, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; /* Don't VERIFY_CONSTANT here. */ if (ctx->quiet && *non_constant_p) break; @@ -5591,7 +6564,8 @@ cxx_eval_bare_aggregate (const constexpr_ctx *ctx, tree t, static tree cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init, bool value_init, value_cat lval, - bool *non_constant_p, bool *overflow_p) + bool *non_constant_p, bool *overflow_p, + tree *jump_target) { tree elttype = TREE_TYPE (atype); verify_ctor_sanity (ctx, atype); @@ -5602,7 +6576,7 @@ cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init, if (init && TREE_CODE (init) == CONSTRUCTOR) return cxx_eval_bare_aggregate (ctx, init, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, jump_target); /* For the default constructor, build up a call to the default constructor of the element type. We only need to handle class types @@ -5639,7 +6613,9 @@ cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init, } tree nelts = get_array_or_vector_nelts (ctx, atype, non_constant_p, - overflow_p); + overflow_p, jump_target); + if (*jump_target) + return NULL_TREE; unsigned HOST_WIDE_INT max = tree_to_uhwi (nelts); for (i = 0; i < max; ++i) { @@ -5665,9 +6641,9 @@ cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init, } else eltinit = cp_build_array_ref (input_location, init, idx, complain); - eltinit = cxx_eval_vec_init_1 (&new_ctx, elttype, eltinit, value_init, - lval, - non_constant_p, overflow_p); + eltinit = cxx_eval_vec_init_1 (&new_ctx, elttype, eltinit, + value_init, lval, non_constant_p, + overflow_p, jump_target); } else if (pre_init) { @@ -5681,7 +6657,8 @@ cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init, /* Clarify what object is being initialized (118285). */ eltinit = build2 (INIT_EXPR, elttype, new_ctx.object, eltinit); eltinit = cxx_eval_constant_expression (&new_ctx, eltinit, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); reuse = i == 0; } else @@ -5697,8 +6674,11 @@ cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init, /* Clarify what object is being initialized (118285). */ eltinit = build2 (INIT_EXPR, elttype, new_ctx.object, eltinit); eltinit = cxx_eval_constant_expression (&new_ctx, eltinit, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); } + if (*jump_target) + return NULL_TREE; if (*non_constant_p) break; if (no_slot) @@ -5748,7 +6728,7 @@ cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init, static tree cxx_eval_vec_init (const constexpr_ctx *ctx, tree t, value_cat lval, - bool *non_constant_p, bool *overflow_p) + bool *non_constant_p, bool *overflow_p, tree *jump_target) { tree atype = TREE_TYPE (t); tree init = VEC_INIT_EXPR_INIT (t); @@ -5780,10 +6760,10 @@ cxx_eval_vec_init (const constexpr_ctx *ctx, tree t, } init = expand_vec_init_expr (ctx->object, t, complain); return cxx_eval_constant_expression (ctx, init, lval, non_constant_p, - overflow_p); + overflow_p, jump_target); } tree r = cxx_eval_vec_init_1 (ctx, atype, init, value_init, - lval, non_constant_p, overflow_p); + lval, non_constant_p, overflow_p, jump_target); if (*non_constant_p) return t; else @@ -5812,14 +6792,16 @@ same_type_ignoring_tlq_and_bounds_p (tree type1, tree type2) otherwise return NULL_TREE. */ static tree -cxx_union_active_member (const constexpr_ctx *ctx, tree t) +cxx_union_active_member (const constexpr_ctx *ctx, tree t, tree *jump_target) { constexpr_ctx new_ctx = *ctx; new_ctx.quiet = true; bool non_constant_p = false, overflow_p = false; tree ctor = cxx_eval_constant_expression (&new_ctx, t, vc_prvalue, &non_constant_p, - &overflow_p); + &overflow_p, jump_target); + if (*jump_target) + return NULL_TREE; if (TREE_CODE (ctor) == CONSTRUCTOR && CONSTRUCTOR_NELTS (ctor) == 1 && CONSTRUCTOR_ELT (ctor, 0)->index @@ -5832,12 +6814,28 @@ cxx_union_active_member (const constexpr_ctx *ctx, tree t) static tree cxx_fold_indirect_ref_1 (const constexpr_ctx *ctx, location_t loc, tree type, - tree op, unsigned HOST_WIDE_INT off, bool *empty_base) + tree op, unsigned HOST_WIDE_INT off, bool *empty_base, + tree *jump_target) { tree optype = TREE_TYPE (op); unsigned HOST_WIDE_INT const_nunits; if (off == 0 && similar_type_p (optype, type)) return op; + else if (cxx_dialect >= cxx26 + && VAR_P (op) + && DECL_VTABLE_OR_VTT_P (op) + && same_type_ignoring_top_level_qualifiers_p (type, + ptrdiff_type_node) + && POINTER_TYPE_P (strip_array_types (optype))) + { + /* We often read some virtual table elements using ptrdiff_t rather + than pointer type. */ + if (tree ret = cxx_fold_indirect_ref_1 (ctx, loc, + strip_array_types (optype), + op, off, empty_base, + jump_target)) + return fold_convert (type, ret); + } else if (TREE_CODE (optype) == COMPLEX_TYPE && similar_type_p (type, TREE_TYPE (optype))) { @@ -5881,7 +6879,7 @@ cxx_fold_indirect_ref_1 (const constexpr_ctx *ctx, location_t loc, tree type, op = build4_loc (loc, ARRAY_REF, TREE_TYPE (optype), op, index, NULL_TREE, NULL_TREE); return cxx_fold_indirect_ref_1 (ctx, loc, type, op, rem, - empty_base); + empty_base, jump_target); } } /* ((foo *)&struct_with_foo_field)[x] => COMPONENT_REF */ @@ -5890,7 +6888,7 @@ cxx_fold_indirect_ref_1 (const constexpr_ctx *ctx, location_t loc, tree type, { if (TREE_CODE (optype) == UNION_TYPE) /* For unions prefer the currently active member. */ - if (tree field = cxx_union_active_member (ctx, op)) + if (tree field = cxx_union_active_member (ctx, op, jump_target)) { unsigned HOST_WIDE_INT el_sz = tree_to_uhwi (TYPE_SIZE_UNIT (TREE_TYPE (field))); @@ -5899,7 +6897,8 @@ cxx_fold_indirect_ref_1 (const constexpr_ctx *ctx, location_t loc, tree type, tree cop = build3 (COMPONENT_REF, TREE_TYPE (field), op, field, NULL_TREE); if (tree ret = cxx_fold_indirect_ref_1 (ctx, loc, type, cop, - off, empty_base)) + off, empty_base, + jump_target)) return ret; } } @@ -5931,15 +6930,21 @@ cxx_fold_indirect_ref_1 (const constexpr_ctx *ctx, location_t loc, tree type, if (!tree_fits_uhwi_p (pos)) continue; unsigned HOST_WIDE_INT upos = tree_to_uhwi (pos); - unsigned HOST_WIDE_INT el_sz - = tree_to_uhwi (TYPE_SIZE_UNIT (TREE_TYPE (field))); + unsigned HOST_WIDE_INT el_sz; + if (DECL_FIELD_IS_BASE (field) + && CLASS_TYPE_P (optype) + && CLASSTYPE_VBASECLASSES (optype)) + el_sz = tree_to_uhwi (DECL_SIZE_UNIT (field)); + else + el_sz = tree_to_uhwi (TYPE_SIZE_UNIT (TREE_TYPE (field))); if (upos <= off && off < upos + el_sz) { tree cop = build3 (COMPONENT_REF, TREE_TYPE (field), op, field, NULL_TREE); if (tree ret = cxx_fold_indirect_ref_1 (ctx, loc, type, cop, off - upos, - empty_base)) + empty_base, + jump_target)) return ret; } } @@ -5959,7 +6964,7 @@ cxx_fold_indirect_ref_1 (const constexpr_ctx *ctx, location_t loc, tree type, static tree cxx_fold_indirect_ref (const constexpr_ctx *ctx, location_t loc, tree type, - tree op0, bool *empty_base /* = NULL*/) + tree op0, bool *empty_base, tree *jump_target) { tree sub = op0; tree subtype; @@ -5983,6 +6988,25 @@ cxx_fold_indirect_ref (const constexpr_ctx *ctx, location_t loc, tree type, offset positive, so that cxx_fold_indirect_ref_1 can identify more folding opportunities. */ auto canonicalize_obj_off = [] (tree& obj, tree& off) { + if (cxx_dialect >= cxx26) + { + /* For C++26, we need to fold *(B *)(&x.D.1234 + 32) used + to access virtual base members. */ + tree nobj = obj; + while (TREE_CODE (nobj) == COMPONENT_REF + && DECL_FIELD_IS_BASE (TREE_OPERAND (nobj, 1))) + nobj = TREE_OPERAND (nobj, 0); + if (nobj != obj + && CLASS_TYPE_P (TREE_TYPE (nobj)) + && CLASSTYPE_VBASECLASSES (TREE_TYPE (nobj))) + while (obj != nobj) + { + tree field = TREE_OPERAND (obj, 1); + tree pos = byte_position (field); + off = int_const_binop (PLUS_EXPR, off, pos); + obj = TREE_OPERAND (obj, 0); + } + } while (TREE_CODE (obj) == COMPONENT_REF /* We need to preserve union member accesses so that we can later properly diagnose accessing the wrong member. */ @@ -6021,8 +7045,9 @@ cxx_fold_indirect_ref (const constexpr_ctx *ctx, location_t loc, tree type, { tree off = integer_zero_node; canonicalize_obj_off (op, off); - gcc_assert (integer_zerop (off)); - return cxx_fold_indirect_ref_1 (ctx, loc, type, op, 0, empty_base); + return cxx_fold_indirect_ref_1 (ctx, loc, type, op, + tree_to_uhwi (off), empty_base, + jump_target); } } else if (TREE_CODE (sub) == POINTER_PLUS_EXPR @@ -6037,7 +7062,8 @@ cxx_fold_indirect_ref (const constexpr_ctx *ctx, location_t loc, tree type, tree obj = TREE_OPERAND (op00, 0); canonicalize_obj_off (obj, off); return cxx_fold_indirect_ref_1 (ctx, loc, type, obj, - tree_to_uhwi (off), empty_base); + tree_to_uhwi (off), empty_base, + jump_target); } } /* *(foo *)fooarrptr => (*fooarrptr)[0] */ @@ -6047,7 +7073,10 @@ cxx_fold_indirect_ref (const constexpr_ctx *ctx, location_t loc, tree type, tree type_domain; tree min_val = size_zero_node; tree newsub - = cxx_fold_indirect_ref (ctx, loc, TREE_TYPE (subtype), sub, NULL); + = cxx_fold_indirect_ref (ctx, loc, TREE_TYPE (subtype), sub, NULL, + jump_target); + if (*jump_target) + return NULL_TREE; if (newsub) sub = newsub; else @@ -6065,7 +7094,8 @@ cxx_fold_indirect_ref (const constexpr_ctx *ctx, location_t loc, tree type, static tree cxx_eval_indirect_ref (const constexpr_ctx *ctx, tree t, value_cat lval, - bool *non_constant_p, bool *overflow_p) + bool *non_constant_p, bool *overflow_p, + tree *jump_target) { tree orig_op0 = TREE_OPERAND (t, 0); bool empty_base = false; @@ -6083,13 +7113,17 @@ cxx_eval_indirect_ref (const constexpr_ctx *ctx, tree t, /* First try to simplify it directly. */ tree r = cxx_fold_indirect_ref (ctx, EXPR_LOCATION (t), TREE_TYPE (t), - orig_op0, &empty_base); + orig_op0, &empty_base, jump_target); + if (*jump_target) + return NULL_TREE; if (!r) { /* If that didn't work, evaluate the operand first. */ tree op0 = cxx_eval_constant_expression (ctx, orig_op0, vc_prvalue, non_constant_p, - overflow_p); + overflow_p, jump_target); + if (*jump_target) + return NULL_TREE; /* Don't VERIFY_CONSTANT here. */ if (*non_constant_p) return t; @@ -6103,7 +7137,9 @@ cxx_eval_indirect_ref (const constexpr_ctx *ctx, tree t, } r = cxx_fold_indirect_ref (ctx, EXPR_LOCATION (t), TREE_TYPE (t), op0, - &empty_base); + &empty_base, jump_target); + if (*jump_target) + return NULL_TREE; if (r == NULL_TREE) { /* We couldn't fold to a constant value. Make sure it's not @@ -6133,7 +7169,10 @@ cxx_eval_indirect_ref (const constexpr_ctx *ctx, tree t, } r = cxx_eval_constant_expression (ctx, r, - lval, non_constant_p, overflow_p); + lval, non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; if (*non_constant_p) return t; @@ -6243,7 +7282,8 @@ non_const_var_error (location_t loc, tree r, bool fundef_p) static tree cxx_eval_trinary_expression (const constexpr_ctx *ctx, tree t, value_cat lval, - bool *non_constant_p, bool *overflow_p) + bool *non_constant_p, bool *overflow_p, + tree *jump_target) { int i; tree args[3]; @@ -6253,7 +7293,10 @@ cxx_eval_trinary_expression (const constexpr_ctx *ctx, tree t, { args[i] = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, i), lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; VERIFY_CONSTANT (args[i]); } @@ -6375,7 +7418,8 @@ modifying_const_object_p (tree_code code, tree obj, bool mutable_p) static tree cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, value_cat lval, - bool *non_constant_p, bool *overflow_p) + bool *non_constant_p, bool *overflow_p, + tree *jump_target) { constexpr_ctx new_ctx = *ctx; @@ -6383,7 +7427,8 @@ cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, if (TREE_CLOBBER_P (init) && CLOBBER_KIND (init) < CLOBBER_OBJECT_END) - /* Only handle clobbers ending the lifetime of objects. */ + /* Only handle clobbers ending the lifetime of objects. + ??? We should probably set CONSTRUCTOR_NO_CLEARING. */ return void_node; /* First we figure out where we're storing to. */ @@ -6400,7 +7445,10 @@ cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, if (!SCALAR_TYPE_P (type)) new_ctx.ctor = new_ctx.object = NULL_TREE; init = cxx_eval_constant_expression (&new_ctx, init, vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; if (*non_constant_p) return t; } @@ -6412,8 +7460,11 @@ cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, as a whole; otherwise, only evaluate the innermost piece to avoid building up unnecessary *_REFs. */ target = cxx_eval_constant_expression (ctx, target, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); evaluated = true; + if (*jump_target) + return NULL_TREE; if (*non_constant_p) return t; } @@ -6439,7 +7490,10 @@ cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, if (TREE_CODE (probe) == ARRAY_REF) { elt = eval_and_check_array_index (ctx, probe, false, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; if (*non_constant_p) return t; } @@ -6496,8 +7550,11 @@ cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, break; } probe = cxx_eval_constant_expression (ctx, probe, vc_glvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); evaluated = true; + if (*jump_target) + return NULL_TREE; if (*non_constant_p) return t; } @@ -6841,7 +7898,10 @@ cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, if (tree tinit = TARGET_EXPR_INITIAL (init)) init = tinit; init = cxx_eval_constant_expression (&new_ctx, init, vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; /* The hash table might have moved since the get earlier, and the initializer might have mutated the underlying CONSTRUCTORs, so we must recompute VALP. */ @@ -6967,7 +8027,8 @@ cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, static tree cxx_eval_increment_expression (const constexpr_ctx *ctx, tree t, value_cat lval, - bool *non_constant_p, bool *overflow_p) + bool *non_constant_p, bool *overflow_p, + tree *jump_target) { enum tree_code code = TREE_CODE (t); tree type = TREE_TYPE (t); @@ -6981,12 +8042,18 @@ cxx_eval_increment_expression (const constexpr_ctx *ctx, tree t, /* The operand as an lvalue. */ op = cxx_eval_constant_expression (ctx, op, vc_glvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; /* The operand as an rvalue. */ tree val = cxx_eval_constant_expression (ctx, op, vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; /* Don't VERIFY_CONSTANT if this might be dealing with a pointer to a local array in a constexpr function. */ bool ptr = INDIRECT_TYPE_P (TREE_TYPE (val)); @@ -7025,8 +8092,11 @@ cxx_eval_increment_expression (const constexpr_ctx *ctx, tree t, tree store = build2_loc (cp_expr_loc_or_loc (t, input_location), MODIFY_EXPR, type, op, mod); mod = cxx_eval_constant_expression (ctx, store, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); ggc_free (store); + if (*jump_target) + return NULL_TREE; if (*non_constant_p) return t; @@ -7040,42 +8110,6 @@ cxx_eval_increment_expression (const constexpr_ctx *ctx, tree t, return val; } -/* Predicates for the meaning of *jump_target. */ - -static bool -returns (tree *jump_target) -{ - return *jump_target - && TREE_CODE (*jump_target) == RETURN_EXPR; -} - -static bool -breaks (tree *jump_target) -{ - return *jump_target - && ((TREE_CODE (*jump_target) == LABEL_DECL - && LABEL_DECL_BREAK (*jump_target)) - || TREE_CODE (*jump_target) == BREAK_STMT - || TREE_CODE (*jump_target) == EXIT_EXPR); -} - -static bool -continues (tree *jump_target) -{ - return *jump_target - && ((TREE_CODE (*jump_target) == LABEL_DECL - && LABEL_DECL_CONTINUE (*jump_target)) - || TREE_CODE (*jump_target) == CONTINUE_STMT); - -} - -static bool -switches (tree *jump_target) -{ - return *jump_target - && TREE_CODE (*jump_target) == INTEGER_CST; -} - /* Subroutine of cxx_eval_statement_list. Determine whether the statement STMT matches *jump_target. If we're looking for a case label and we see the default label, note it in ctx->css_state. */ @@ -7123,6 +8157,11 @@ label_matches (const constexpr_ctx *ctx, tree *jump_target, tree stmt) breaks (jump_target) or continues (jump_target). */ break; + case VAR_DECL: + /* Uncaught exception. This is handled by TRY_BLOCK evaluation + and other places by testing throws (jump_target). */ + break; + default: gcc_unreachable (); } @@ -7137,15 +8176,9 @@ cxx_eval_statement_list (const constexpr_ctx *ctx, tree t, bool *non_constant_p, bool *overflow_p, tree *jump_target) { - tree local_target; /* In a statement-expression we want to return the last value. For empty statement expression return void_node. */ tree r = void_node; - if (!jump_target) - { - local_target = NULL_TREE; - jump_target = &local_target; - } for (tree_stmt_iterator i = tsi_start (t); !tsi_end_p (i); ++i) { tree stmt = *i; @@ -7173,18 +8206,11 @@ cxx_eval_statement_list (const constexpr_ctx *ctx, tree t, jump_target); if (*non_constant_p) break; - if (returns (jump_target) || breaks (jump_target)) + if (returns (jump_target) + || breaks (jump_target) + || throws (jump_target)) break; } - if (*jump_target && jump_target == &local_target) - { - /* We aren't communicating the jump to our caller, so give up. We don't - need to support evaluation of jumps out of statement-exprs. */ - if (!ctx->quiet) - error_at (cp_expr_loc_or_input_loc (r), - "statement is not a constant expression"); - *non_constant_p = true; - } return r; } @@ -7196,13 +8222,6 @@ cxx_eval_loop_expr (const constexpr_ctx *ctx, tree t, bool *non_constant_p, bool *overflow_p, tree *jump_target) { - tree local_target; - if (!jump_target) - { - local_target = NULL_TREE; - jump_target = &local_target; - } - tree body, cond = NULL_TREE, expr = NULL_TREE; tree cond_prep = NULL_TREE, cond_cleanup = NULL_TREE; unsigned cond_cleanup_depth = 0; @@ -7258,7 +8277,7 @@ cxx_eval_loop_expr (const constexpr_ctx *ctx, tree t, tree c; FOR_EACH_VEC_ELT_REVERSE (cleanups, i, c) cxx_eval_constant_expression (ctx, c, vc_discard, non_constant_p, - overflow_p); + overflow_p, jump_target); } if (cond_prep) for (tree decl = BIND_EXPR_VARS (cond_prep); @@ -7353,7 +8372,8 @@ cxx_eval_loop_expr (const constexpr_ctx *ctx, tree t, if (*non_constant_p || returns (jump_target) || breaks (jump_target) - || continues (jump_target)) + || continues (jump_target) + || throws (jump_target)) { depth = 1; break; @@ -7400,6 +8420,7 @@ cxx_eval_loop_expr (const constexpr_ctx *ctx, tree t, && !breaks (jump_target) && !continues (jump_target) && (!switches (jump_target) || count == 0) + && !throws (jump_target) && !*non_constant_p); cleanup_cond (); @@ -7418,7 +8439,10 @@ cxx_eval_switch_expr (const constexpr_ctx *ctx, tree t, tree cond = TREE_CODE (t) == SWITCH_STMT ? SWITCH_STMT_COND (t) : SWITCH_COND (t); cond = cxx_eval_constant_expression (ctx, cond, vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; VERIFY_CONSTANT (cond); if (TREE_CODE (cond) != INTEGER_CST) { @@ -7551,7 +8575,8 @@ maybe_warn_about_constant_value (location_t loc, tree decl) static tree build_new_constexpr_heap_type (const constexpr_ctx *ctx, tree elt_type, tree cookie_size, tree full_size, tree arg_size, - bool *non_constant_p, bool *overflow_p) + bool *non_constant_p, bool *overflow_p, + tree *jump_target) { gcc_assert (cookie_size == NULL_TREE || tree_fits_uhwi_p (cookie_size)); gcc_assert (tree_fits_uhwi_p (full_size)); @@ -7587,13 +8612,17 @@ build_new_constexpr_heap_type (const constexpr_ctx *ctx, tree elt_type, if (integer_zerop (op0)) arg_size = cxx_eval_constant_expression (ctx, op1, vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); else if (integer_zerop (op1)) arg_size = cxx_eval_constant_expression (ctx, op0, vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); else arg_size = NULL_TREE; + if (*jump_target) + return NULL_TREE; } else arg_size = NULL_TREE; @@ -7614,6 +8643,38 @@ build_new_constexpr_heap_type (const constexpr_ctx *ctx, tree elt_type, return build_new_constexpr_heap_type (elt_type, cookie_size, itype2); } +/* Handle the case when a cleanup of some expression throws. JMP_TARGET + indicates whether the cleanup threw or not, *JUMP_TARGET indicates whether + the expression which needed the cleanup threw. If both threw, diagnose + it and return NULL, otherwise return R. If only the cleanup threw, set + *JUMP_TARGET to the exception object from the cleanup. */ + +static tree +merge_jump_target (location_t loc, const constexpr_ctx *ctx, tree r, + bool *non_constant_p, tree *jump_target, tree jmp_target) +{ + if (!throws (&jmp_target)) + return r; + if (throws (jump_target)) + { + /* [except.throw]/9 - If the exception handling mechanism + handling an uncaught exception directly invokes a function + that exits via an exception, the function std::terminate is + invoked. */ + if (!ctx->quiet) + { + auto_diagnostic_group d; + diagnose_std_terminate (loc, ctx, *jump_target); + inform (loc, "destructor exited with an exception"); + } + *non_constant_p = true; + *jump_target = NULL_TREE; + return NULL_TREE; + } + *jump_target = jmp_target; + return r; +} + /* Attempt to reduce the expression T to a constant value. On failure, issue diagnostic and return error_mark_node. */ /* FIXME unify with c_fully_fold */ @@ -7623,9 +8684,9 @@ static tree cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, value_cat lval, bool *non_constant_p, bool *overflow_p, - tree *jump_target /* = NULL */) + tree *jump_target) { - if (jump_target && *jump_target) + if (*jump_target) { /* If we are jumping, ignore all statements/expressions except those that could have LABEL_EXPR or CASE_LABEL_EXPR in their bodies. */ @@ -7749,7 +8810,7 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, r = convert_from_reference (r); } return cxx_eval_constant_expression (ctx, r, lval, non_constant_p, - overflow_p); + overflow_p, jump_target); } /* fall through */ case CONST_DECL: @@ -7792,7 +8853,7 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, r = TARGET_EXPR_INITIAL (r); if (DECL_P (r) /* P2280 allows references to unknown. */ - && !(VAR_P (t) && TYPE_REF_P (TREE_TYPE (t)))) + && !(p2280_active_p (ctx) && VAR_P (t) && TYPE_REF_P (TREE_TYPE (t)))) { if (!ctx->quiet) non_const_var_error (loc, r, /*fundef_p*/false); @@ -7811,6 +8872,7 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, case LABEL_EXPR: case CASE_LABEL_EXPR: case PREDICT_EXPR: + case OMP_DECLARE_MAPPER: return t; case PARM_DECL: @@ -7826,7 +8888,10 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, r = v; if (TREE_ADDRESSABLE (TREE_TYPE (t))) r = cxx_eval_constant_expression (ctx, r, vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; } else if (lval) /* Defer in case this is only used for its type. */; @@ -7844,9 +8909,9 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, r = build_constructor (TREE_TYPE (t), NULL); TREE_CONSTANT (r) = true; } - else if (TYPE_REF_P (TREE_TYPE (t))) + else if (p2280_active_p (ctx) && TYPE_REF_P (TREE_TYPE (t))) /* P2280 allows references to unknown... */; - else if (is_this_parameter (t)) + else if (p2280_active_p (ctx) && is_this_parameter (t)) /* ...as well as the this pointer. */; else { @@ -7859,7 +8924,7 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, case CALL_EXPR: case AGGR_INIT_EXPR: r = cxx_eval_call_expression (ctx, t, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, jump_target); break; case DECL_EXPR: @@ -7923,7 +8988,10 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, if (tree init = DECL_INITIAL (r)) { init = cxx_eval_constant_expression (ctx, init, vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; /* Don't share a CONSTRUCTOR that might be changed. */ init = unshare_constructor (init); /* Remember that a constant object's constructor has already @@ -7982,14 +9050,23 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, ctx->global->put_value (new_ctx.object, new_ctx.ctor); ctx = &new_ctx; } + + /* If the initializer is complex, evaluate it to initialize slot. */ + bool is_complex = target_expr_needs_replace (t); + if (is_complex) + /* In case no initialization actually happens, clear out any + void_node from a previous evaluation. */ + ctx->global->put_value (slot, NULL_TREE); + /* Pass vc_prvalue because this indicates initialization of a temporary. */ r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); if (*non_constant_p) break; - /* If the initializer is complex, evaluate it to initialize slot. */ - bool is_complex = target_expr_needs_replace (t); + if (*jump_target) + return NULL_TREE; if (!is_complex) { r = unshare_constructor (r); @@ -7997,8 +9074,15 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, r = adjust_temp_type (type, r); ctx->global->put_value (slot, r); } - if (TARGET_EXPR_CLEANUP (t) && !CLEANUP_EH_ONLY (t)) - ctx->global->cleanups->safe_push (TARGET_EXPR_CLEANUP (t)); + if (TARGET_EXPR_CLEANUP (t) + && (!CLEANUP_EH_ONLY (t) || cxx_dialect >= cxx26)) + { + ctx->global->cleanups->safe_push (TARGET_EXPR_CLEANUP (t)); + /* Mark CLEANUP_EH_ONLY cleanups by pushing NULL_TREE after + them. */ + if (CLEANUP_EH_ONLY (t)) + ctx->global->cleanups->safe_push (NULL_TREE); + } if (ctx->save_exprs) ctx->save_exprs->safe_push (slot); if (lval) @@ -8012,33 +9096,28 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, case MODIFY_EXPR: gcc_assert (jump_target == NULL || *jump_target == NULL_TREE); r = cxx_eval_store_expression (ctx, t, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, jump_target); break; case SCOPE_REF: r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); break; case RETURN_EXPR: if (TREE_OPERAND (t, 0) != NULL_TREE) r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, - non_constant_p, overflow_p); - /* FALLTHRU */ + non_constant_p, overflow_p, + jump_target); + if (!throws (jump_target)) + *jump_target = t; + break; case BREAK_STMT: case CONTINUE_STMT: - if (jump_target) - *jump_target = t; - else - { - /* Can happen with ({ return true; }) && false; passed to - maybe_constant_value. There is nothing to jump over in this - case, and the bug will be diagnosed later. */ - gcc_assert (ctx->quiet); - *non_constant_p = true; - } + *jump_target = t; break; case SAVE_EXPR: @@ -8047,9 +9126,10 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, r = v; else { - r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), vc_prvalue, - non_constant_p, overflow_p); - if (*non_constant_p) + r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), + vc_prvalue, non_constant_p, + overflow_p, jump_target); + if (*non_constant_p || *jump_target) break; ctx->global->put_value (t, r); if (ctx->save_exprs) @@ -8057,16 +9137,7 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, } break; - case TRY_CATCH_EXPR: - if (TREE_OPERAND (t, 0) == NULL_TREE) - { - r = void_node; - break; - } - /* FALLTHRU */ case NON_LVALUE_EXPR: - case TRY_BLOCK: - case MUST_NOT_THROW_EXPR: case EXPR_STMT: case EH_SPEC_BLOCK: r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), @@ -8075,6 +9146,42 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, jump_target); break; + case TRY_BLOCK: + r = cxx_eval_constant_expression (ctx, TRY_STMTS (t), lval, + non_constant_p, overflow_p, + jump_target); + if (!*non_constant_p && throws (jump_target)) + if (tree h = TRY_HANDLERS (t)) + { + tree type = strip_array_types (TREE_TYPE (*jump_target)); + if (TREE_CODE (h) == STATEMENT_LIST) + { + for (tree stmt : tsi_range (h)) + if (TREE_CODE (stmt) == HANDLER + && handler_match_for_exception_type (stmt, type)) + { + h = stmt; + break; + } + if (TREE_CODE (h) == STATEMENT_LIST) + h = NULL_TREE; + } + else if (TREE_CODE (h) != HANDLER + || !handler_match_for_exception_type (h, type)) + h = NULL_TREE; + if (h) + { + gcc_assert (VAR_P (*jump_target)); + ctx->global->caught_exceptions.safe_push (*jump_target); + ctx->global->caught_exceptions.safe_push (HANDLER_TYPE (h)); + *jump_target = NULL_TREE; + r = cxx_eval_constant_expression (ctx, HANDLER_BODY (h), + vc_discard, non_constant_p, + overflow_p, jump_target); + } + } + break; + case CLEANUP_POINT_EXPR: { auto_vec<tree, 2> cleanups; @@ -8092,47 +9199,132 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, ctx->global->cleanups = prev_cleanups; unsigned int i; - tree cleanup; + tree cleanup, jmp_target = NULL_TREE; + bool eh = throws (jump_target); /* Evaluate the cleanups. */ FOR_EACH_VEC_ELT_REVERSE (cleanups, i, cleanup) - cxx_eval_constant_expression (&new_ctx, cleanup, vc_discard, - non_constant_p, overflow_p); + if (cleanup == NULL_TREE) + { + /* NULL_TREE cleanup is a marker that before it is + CLEANUP_EH_ONLY cleanup. Skip the cleanup before it + if the body didn't throw. */ + if (!eh) + --i; + } + else + cxx_eval_constant_expression (&new_ctx, cleanup, vc_discard, + non_constant_p, overflow_p, + &jmp_target); /* Forget SAVE_EXPRs and TARGET_EXPRs created by this full-expression. */ for (tree save_expr : save_exprs) destroy_value_checked (ctx, save_expr, non_constant_p); + if (throws (&jmp_target)) + *jump_target = jmp_target; } break; + case MUST_NOT_THROW_EXPR: + r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), + lval, + non_constant_p, overflow_p, + jump_target); + if (throws (jump_target)) + { + /* [except.handle]/7 - If the search for a handler exits the + function body of a function with a non-throwing exception + specification, the function std::terminate is invoked. */ + if (!ctx->quiet) + { + auto_diagnostic_group d; + diagnose_std_terminate (loc, ctx, *jump_target); + if (MUST_NOT_THROW_NOEXCEPT_P (t) + && ctx->call + && ctx->call->fundef) + inform (loc, "uncaught exception exited from %<noexcept%> " + "function %qD", + ctx->call->fundef->decl); + else if (MUST_NOT_THROW_THROW_P (t)) + inform (loc, "destructor exited with an exception after " + "initializing the exception object"); + else if (MUST_NOT_THROW_CATCH_P (t)) + inform (loc, "constructor exited with another exception while " + "entering handler"); + } + *non_constant_p = true; + *jump_target = NULL_TREE; + r = NULL_TREE; + } + break; + + case TRY_CATCH_EXPR: + if (TREE_OPERAND (t, 0) == NULL_TREE) + { + r = void_node; + break; + } + r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, + non_constant_p, overflow_p, + jump_target); + if (!*non_constant_p && throws (jump_target)) + { + tree jmp_target = NULL_TREE; + cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), vc_discard, + non_constant_p, overflow_p, + &jmp_target); + r = merge_jump_target (loc, ctx, r, non_constant_p, jump_target, + jmp_target); + } + break; + case TRY_FINALLY_EXPR: r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, non_constant_p, overflow_p, jump_target); if (!*non_constant_p) - /* Also evaluate the cleanup. */ - cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), vc_discard, - non_constant_p, overflow_p); + { + tree jmp_target = NULL_TREE; + /* Also evaluate the cleanup. */ + if (TREE_CODE (TREE_OPERAND (t, 1)) == EH_ELSE_EXPR + && throws (jump_target)) + cxx_eval_constant_expression (ctx, + TREE_OPERAND (TREE_OPERAND (t, 1), + 1), vc_discard, + non_constant_p, overflow_p, + &jmp_target); + else + cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), vc_discard, + non_constant_p, overflow_p, + &jmp_target); + r = merge_jump_target (loc, ctx, r, non_constant_p, jump_target, + jmp_target); + } break; case EH_ELSE_EXPR: /* Evaluate any cleanup that applies to non-EH exits. */ cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), vc_discard, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); - /* We do not have constexpr exceptions yet, so skip the EH path. */ + /* The EH path is handled in TRY_FINALLY_EXPR handling above. */ break; case CLEANUP_STMT: r = cxx_eval_constant_expression (ctx, CLEANUP_BODY (t), lval, non_constant_p, overflow_p, jump_target); - if (!CLEANUP_EH_ONLY (t) && !*non_constant_p) + if ((!CLEANUP_EH_ONLY (t) || throws (jump_target)) && !*non_constant_p) { iloc_sentinel ils (loc); + tree jmp_target = NULL_TREE; /* Also evaluate the cleanup. */ cxx_eval_constant_expression (ctx, CLEANUP_EXPR (t), vc_discard, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + &jmp_target); + r = merge_jump_target (loc, ctx, r, non_constant_p, jump_target, + jmp_target); } break; @@ -8142,14 +9334,18 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, case MEM_REF: case INDIRECT_REF: r = cxx_eval_indirect_ref (ctx, t, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); break; case ADDR_EXPR: { tree oldop = TREE_OPERAND (t, 0); tree op = cxx_eval_constant_expression (ctx, oldop, vc_glvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; /* Don't VERIFY_CONSTANT here. */ if (*non_constant_p) return t; @@ -8169,7 +9365,10 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, if (lval) { r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; if (r == error_mark_node) ; else if (r == TREE_OPERAND (t, 0) || lval == vc_discard) @@ -8190,7 +9389,8 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, case FIXED_CONVERT_EXPR: case VEC_DUPLICATE_EXPR: r = cxx_eval_unary_expression (ctx, t, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); break; case SIZEOF_EXPR: @@ -8228,6 +9428,8 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, cxx_eval_constant_expression (ctx, op0, vc_discard, non_constant_p, overflow_p, jump_target); + if (*jump_target) + return NULL_TREE; if (*non_constant_p) return t; op1 = TREE_OPERAND (t, 1); @@ -8280,7 +9482,8 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, case RANGE_EXPR: case COMPLEX_EXPR: r = cxx_eval_binary_expression (ctx, t, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); break; /* fold can introduce non-IF versions of these; still treat them as @@ -8289,19 +9492,22 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, case TRUTH_ANDIF_EXPR: r = cxx_eval_logical_expression (ctx, t, boolean_false_node, boolean_true_node, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); break; case TRUTH_OR_EXPR: case TRUTH_ORIF_EXPR: r = cxx_eval_logical_expression (ctx, t, boolean_true_node, boolean_false_node, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); break; case ARRAY_REF: r = cxx_eval_array_reference (ctx, t, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); break; case COMPONENT_REF: @@ -8316,17 +9522,19 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, return t; } r = cxx_eval_component_reference (ctx, t, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); break; case BIT_FIELD_REF: r = cxx_eval_bit_field_ref (ctx, t, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); break; case COND_EXPR: case IF_STMT: - if (jump_target && *jump_target) + if (*jump_target) { tree orig_jump = *jump_target; tree arg = ((TREE_CODE (t) != IF_STMT || TREE_OPERAND (t, 1)) @@ -8364,7 +9572,7 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, break; case VEC_COND_EXPR: r = cxx_eval_vector_conditional_expression (ctx, t, non_constant_p, - overflow_p); + overflow_p, jump_target); break; case CONSTRUCTOR: @@ -8376,7 +9584,7 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, return t; } r = cxx_eval_bare_aggregate (ctx, t, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, jump_target); break; case VEC_INIT_EXPR: @@ -8386,12 +9594,13 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, or xvalue of the same type, meaning direct-initialization from the corresponding member. */ r = cxx_eval_vec_init (ctx, t, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, jump_target); break; case VEC_PERM_EXPR: r = cxx_eval_trinary_expression (ctx, t, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); break; case PAREN_EXPR: @@ -8399,7 +9608,8 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, /* A PAREN_EXPR resulting from __builtin_assoc_barrier has no effect in constant expressions since it's unaffected by -fassociative-math. */ r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); break; case NOP_EXPR: @@ -8423,7 +9633,10 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, ? vc_discard : tcode == VIEW_CONVERT_EXPR ? lval : vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; if (*non_constant_p) return t; tree type = TREE_TYPE (t); @@ -8434,7 +9647,7 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, if (TREE_CODE (t) == CONVERT_EXPR && ARITHMETIC_TYPE_P (type) && INDIRECT_TYPE_P (TREE_TYPE (op)) - && ctx->manifestly_const_eval == mce_true) + && ctx->strict) { if (!ctx->quiet) error_at (loc, @@ -8480,7 +9693,10 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, { if (integer_zerop (sop)) return build_int_cst (type, 0); - r = cxx_fold_indirect_ref (ctx, loc, TREE_TYPE (type), sop); + r = cxx_fold_indirect_ref (ctx, loc, TREE_TYPE (type), sop, + NULL, jump_target); + if (*jump_target) + return NULL_TREE; if (r) { r = build1 (ADDR_EXPR, type, r); @@ -8586,7 +9802,7 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, tree cookie_size = NULL_TREE; tree arg_size = NULL_TREE; if (TREE_CODE (elt_type) == RECORD_TYPE - && TYPE_NAME (elt_type) == heap_identifier) + && TYPE_IDENTIFIER (elt_type) == heap_identifier) { tree fld1 = TYPE_FIELDS (elt_type); tree fld2 = DECL_CHAIN (fld1); @@ -8607,10 +9823,14 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, if (cxx_replaceable_global_alloc_fn (fun) && IDENTIFIER_NEW_OP_P (DECL_NAME (fun))) arg_size = CALL_EXPR_ARG (oldop, 0); - TREE_TYPE (var) + tree new_type = build_new_constexpr_heap_type (ctx, elt_type, cookie_size, var_size, arg_size, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; + TREE_TYPE (var) = new_type; TREE_TYPE (TREE_OPERAND (op, 0)) = build_pointer_type (TREE_TYPE (var)); } @@ -8649,7 +9869,10 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, tree op = cxx_eval_constant_expression (ctx, oldop, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; if (*non_constant_p) return t; r = fold_convert (TREE_TYPE (t), op); @@ -8686,14 +9909,20 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, case PREDECREMENT_EXPR: case POSTDECREMENT_EXPR: return cxx_eval_increment_expression (ctx, t, - lval, non_constant_p, overflow_p); + lval, non_constant_p, overflow_p, + jump_target); + case THROW_EXPR: + if (cxx_dialect >= cxx26) + return cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, + non_constant_p, overflow_p, + jump_target); + /* FALLTHROUGH */ case LAMBDA_EXPR: case NEW_EXPR: case VEC_NEW_EXPR: case DELETE_EXPR: case VEC_DELETE_EXPR: - case THROW_EXPR: case MODOP_EXPR: /* GCC internal stuff. */ case VA_ARG_EXPR: @@ -8707,7 +9936,8 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, case OBJ_TYPE_REF: /* Virtual function lookup. We don't need to do anything fancy. */ return cxx_eval_constant_expression (ctx, OBJ_TYPE_REF_EXPR (t), - lval, non_constant_p, overflow_p); + lval, non_constant_p, overflow_p, + jump_target); case PLACEHOLDER_EXPR: /* Use of the value or address of the current object. */ @@ -8717,7 +9947,8 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, return ctor; else return cxx_eval_constant_expression (ctx, ctor, lval, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); } /* A placeholder without a referent. We can get here when checking whether NSDMIs are noexcept, or in massage_init_elt; @@ -8730,7 +9961,10 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, { tree cond = TREE_OPERAND (t, 0); cond = cxx_eval_constant_expression (ctx, cond, vc_prvalue, - non_constant_p, overflow_p); + non_constant_p, overflow_p, + jump_target); + if (*jump_target) + return NULL_TREE; VERIFY_CONSTANT (cond); if (integer_nonzerop (cond)) *jump_target = t; @@ -8842,7 +10076,7 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, *non_constant_p = true; return t; } - r = cxx_eval_bit_cast (ctx, t, non_constant_p, overflow_p); + r = cxx_eval_bit_cast (ctx, t, non_constant_p, overflow_p, jump_target); break; case OMP_PARALLEL: @@ -8981,20 +10215,6 @@ find_heap_var_refs (tree *tp, int *walk_subtrees, void */*data*/) return NULL_TREE; } -/* Look for deleted heap variables in the expression *TP. */ - -static tree -find_deleted_heap_var (tree *tp, int *walk_subtrees, void */*data*/) -{ - if (VAR_P (*tp) - && DECL_NAME (*tp) == heap_deleted_identifier) - return *tp; - - if (TYPE_P (*tp)) - *walk_subtrees = 0; - return NULL_TREE; -} - /* Find immediate function decls in *TP if any. */ static tree @@ -9100,6 +10320,15 @@ cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, tree fndecl = cp_get_callee_fndecl_nofold (x); if (fndecl && DECL_IMMEDIATE_FUNCTION_P (fndecl)) is_consteval = true; + /* Don't try to evaluate a std::vector constructor taking an integer, it + will fail in the 'if (heap_var)' block below after doing all the work + (c++/113835). This will need adjustment if P3554 is accepted. Note + that evaluation of e.g. the vector default constructor can succeed, so + we don't shortcut all vector constructors. */ + if (fndecl && DECL_CONSTRUCTOR_P (fndecl) && allow_non_constant + && is_std_class (type, "vector") && call_expr_nargs (x) > 1 + && TREE_CODE (TREE_TYPE (get_nth_callarg (x, 1))) == INTEGER_TYPE) + return t; } if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type)) { @@ -9166,30 +10395,67 @@ cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, if (manifestly_const_eval == mce_true) instantiate_constexpr_fns (r); + tree jmp_target = NULL_TREE; r = cxx_eval_constant_expression (&ctx, r, vc_prvalue, - &non_constant_p, &overflow_p); + &non_constant_p, &overflow_p, + &jmp_target); + if (throws (&jmp_target) && !non_constant_p) + { + if (!ctx.quiet) + diagnose_uncaught_exception (input_location, &ctx, jmp_target); + non_constant_p = true; + jmp_target = NULL_TREE; + r = t; + } + else if (!non_constant_p && jmp_target) + { + non_constant_p = true; + if (!ctx.quiet) + { + if (breaks (&jmp_target)) + error ("%<break%> outside of a loop or %<switch%>"); + else if (continues (&jmp_target)) + error ("%<continue%> outside of a loop"); + else if (returns (&jmp_target)) + error ("%<return%> in a statement expression"); + else + gcc_unreachable (); + } + r = t; + } /* If we got a non-simple TARGET_EXPR, the initializer was a sequence of statements, and the result ought to be stored in ctx.ctor. */ if (r == void_node && !constexpr_dtor && ctx.ctor) r = ctx.ctor; - if (!constexpr_dtor) - verify_constant (r, allow_non_constant, &non_constant_p, &overflow_p); - else - DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (object) = true; - unsigned int i; tree cleanup; + jmp_target = NULL_TREE; /* Evaluate the cleanups. */ FOR_EACH_VEC_ELT_REVERSE (cleanups, i, cleanup) - cxx_eval_constant_expression (&ctx, cleanup, vc_discard, - &non_constant_p, &overflow_p); + if (cleanup == NULL_TREE) + /* NULL_TREE cleanup is a marker that before it is + CLEANUP_EH_ONLY cleanup. Skip the cleanup before it. */ + --i; + else + cxx_eval_constant_expression (&ctx, cleanup, vc_discard, + &non_constant_p, &overflow_p, + &jmp_target); + if (throws (&jmp_target) && !non_constant_p) + { + if (!ctx.quiet) + diagnose_uncaught_exception (input_location, &ctx, jmp_target); + non_constant_p = true; + r = t; + } /* Mutable logic is a bit tricky: we want to allow initialization of constexpr variables with mutable members, but we can't copy those members to another constexpr variable. */ - if (TREE_CODE (r) == CONSTRUCTOR && CONSTRUCTOR_MUTABLE_POISON (r)) + if (!non_constant_p + && TREE_CODE (r) == CONSTRUCTOR + && CONSTRUCTOR_MUTABLE_POISON (r)) { if (!allow_non_constant) error ("%qE is not a constant expression because it refers to " @@ -9197,15 +10463,6 @@ cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, non_constant_p = true; } - if (TREE_CODE (r) == CONSTRUCTOR && CONSTRUCTOR_NO_CLEARING (r)) - { - if (!allow_non_constant) - error ("%qE is not a constant expression because it refers to " - "an incompletely initialized variable", t); - TREE_CONSTANT (r) = false; - non_constant_p = true; - } - if (!non_constant_p && cxx_dialect >= cxx20 && !global_ctx.heap_vars.is_empty ()) { @@ -9215,9 +10472,16 @@ cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, if (heap_var) { if (!allow_non_constant && !non_constant_p) - error_at (DECL_SOURCE_LOCATION (heap_var), - "%qE is not a constant expression because it refers to " - "a result of %<operator new%>", t); + { + if (DECL_LANG_SPECIFIC (heap_var)) + error ("%qE is not a constant expression because it refers to " + "exception object allocated with " + "%<__cxa_allocate_exception%>", t); + else + error ("%qE is not a constant expression because it refers to " + "a result of %<operator new%>", t); + inform (DECL_SOURCE_LOCATION (heap_var), "allocated here"); + } r = t; non_constant_p = true; } @@ -9226,13 +10490,14 @@ cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, if (DECL_NAME (heap_var) != heap_deleted_identifier) { if (!allow_non_constant && !non_constant_p) - error_at (DECL_SOURCE_LOCATION (heap_var), - "%qE is not a constant expression because allocated " - "storage has not been deallocated", t); + { + error ("%qE is not a constant expression because allocated " + "storage has not been deallocated", t); + inform (DECL_SOURCE_LOCATION (heap_var), "allocated here"); + } r = t; non_constant_p = true; } - varpool_node::get (heap_var)->remove (); } } @@ -9258,6 +10523,20 @@ cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, non_constant_p = true; } + if (!non_constant_p && !constexpr_dtor) + verify_constant (r, allow_non_constant, &non_constant_p, &overflow_p); + + /* After verify_constant because reduced_constant_expression_p can unset + CONSTRUCTOR_NO_CLEARING. */ + if (TREE_CODE (r) == CONSTRUCTOR && CONSTRUCTOR_NO_CLEARING (r)) + { + if (!allow_non_constant) + error ("%qE is not a constant expression because it refers to " + "an incompletely initialized variable", t); + TREE_CONSTANT (r) = false; + non_constant_p = true; + } + if (non_constant_p) /* If we saw something bad, go back to our argument. The wrapping below is only for the cases of TREE_CONSTANT argument or overflow. */ @@ -9274,13 +10553,17 @@ cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, if (non_constant_p && !allow_non_constant) return error_mark_node; - else if (constexpr_dtor) - return r; else if (non_constant_p && TREE_CONSTANT (r)) r = mark_non_constant (r); else if (non_constant_p) return t; + if (constexpr_dtor) + { + DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (object) = true; + return r; + } + /* Check we are not trying to return the wrong type. */ if (!same_type_ignoring_top_level_qualifiers_p (type, TREE_TYPE (r))) { @@ -9300,7 +10583,8 @@ cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, if (TREE_CODE (t) == TARGET_EXPR && TARGET_EXPR_INITIAL (t) == r) return t; - else if (TREE_CODE (t) == CONSTRUCTOR || TREE_CODE (t) == CALL_EXPR) + else if (TREE_CODE (t) == CONSTRUCTOR || TREE_CODE (t) == CALL_EXPR + || TREE_CODE (t) == AGGR_INIT_EXPR) /* Don't add a TARGET_EXPR if our argument didn't have one. */; else if (TREE_CODE (t) == TARGET_EXPR && TARGET_EXPR_CLEANUP (t)) r = get_target_expr (r); @@ -9431,6 +10715,9 @@ fold_simple (tree t) tree fold_to_constant (tree t) { + if (processing_template_decl) + return t; + tree r = fold (t); if (CONSTANT_CLASS_P (r) && !TREE_OVERFLOW (r)) return r; @@ -9450,8 +10737,35 @@ tree maybe_constant_value (tree t, tree decl /* = NULL_TREE */, mce_value manifestly_const_eval /* = mce_unknown */) { + tree orig_t = t; tree r; + if (EXPR_P (t) && manifestly_const_eval == mce_unknown) + { + /* Look up each operand in the cv_cache first to see if we've already + reduced it, and reuse that result to avoid quadratic behavior if + we're called when building up a large expression. */ + int n = cp_tree_operand_length (t); + tree *ops = XALLOCAVEC (tree, n); + bool rebuild = false; + for (int i = 0; i < n; ++i) + { + ops[i] = TREE_OPERAND (t, i); + if (tree *cached = hash_map_safe_get (cv_cache, ops[i])) + if (*cached != ops[i]) + { + ops[i] = *cached; + rebuild = true; + } + } + if (rebuild) + { + t = copy_node (t); + for (int i = 0; i < n; ++i) + TREE_OPERAND (t, i) = ops[i]; + } + } + if (!is_nondependent_constant_expression (t)) { if (TREE_OVERFLOW_P (t) @@ -9469,6 +10783,10 @@ maybe_constant_value (tree t, tree decl /* = NULL_TREE */, return fold_to_constant (t); if (manifestly_const_eval != mce_unknown) + /* TODO: Extend the cache to be mce_value aware. And if we have a + previously cached mce_unknown result that's TREE_CONSTANT, it means + the reduced value is independent of mce_value and so we should + be able to reuse it in the mce_true/false case. */ return cxx_eval_outermost_constant_expr (t, true, true, manifestly_const_eval, false, decl); @@ -9498,7 +10816,7 @@ maybe_constant_value (tree t, tree decl /* = NULL_TREE */, || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) || !cp_tree_equal (r, t)); if (!c.evaluation_restricted_p ()) - cv_cache->put (t, r); + cv_cache->put (orig_t, r); return r; } @@ -9662,7 +10980,7 @@ fold_non_dependent_init (tree t, static tree maybe_constant_init_1 (tree t, tree decl, bool allow_non_constant, - bool manifestly_const_eval) + mce_value manifestly_const_eval) { if (!t) return t; @@ -9688,17 +11006,27 @@ maybe_constant_init_1 (tree t, tree decl, bool allow_non_constant, { /* [basic.start.static] allows constant-initialization of variables with static or thread storage duration even if it isn't required, but we - shouldn't bend the rules the same way for automatic variables. */ + shouldn't bend the rules the same way for automatic variables. + + But still enforce the requirements of constexpr/constinit. + [dcl.constinit] "If a variable declared with the constinit specifier + has dynamic initialization, the program is ill-formed, even if the + implementation would perform that initialization as a static + initialization." */ bool is_static = (decl && DECL_P (decl) && (TREE_STATIC (decl) || DECL_EXTERNAL (decl))); + bool strict = (!is_static + || (decl && DECL_P (decl) + && (DECL_DECLARED_CONSTEXPR_P (decl) + || DECL_DECLARED_CONSTINIT_P (decl)))); if (is_static) - manifestly_const_eval = true; + manifestly_const_eval = mce_true; - if (cp_unevaluated_operand && !manifestly_const_eval) + if (cp_unevaluated_operand && manifestly_const_eval != mce_true) return fold_to_constant (t); - t = cxx_eval_outermost_constant_expr (t, allow_non_constant, !is_static, - mce_value (manifestly_const_eval), + t = cxx_eval_outermost_constant_expr (t, allow_non_constant, strict, + manifestly_const_eval, false, decl); } if (TREE_CODE (t) == TARGET_EXPR) @@ -9715,6 +11043,12 @@ maybe_constant_init_1 (tree t, tree decl, bool allow_non_constant, tree maybe_constant_init (tree t, tree decl, bool manifestly_const_eval) { + return maybe_constant_init_1 (t, decl, true, mce_value (manifestly_const_eval)); +} + +tree +maybe_constant_init (tree t, tree decl, mce_value manifestly_const_eval) +{ return maybe_constant_init_1 (t, decl, true, manifestly_const_eval); } @@ -9723,7 +11057,25 @@ maybe_constant_init (tree t, tree decl, bool manifestly_const_eval) tree cxx_constant_init (tree t, tree decl) { - return maybe_constant_init_1 (t, decl, false, true); + return maybe_constant_init_1 (t, decl, false, mce_true); +} + +/* Return true if CALL_EXPR T might throw during constant evaluation. */ + +static bool +callee_might_throw (tree t) +{ + if (cxx_dialect < cxx26 || !flag_exceptions) + return false; + tree callee = cp_get_callee (t); + if (callee == NULL_TREE) + return false; + tree callee_fn = cp_get_fndecl_from_callee (callee, false); + return (!flag_enforce_eh_specs + || type_dependent_expression_p (callee) + || !POINTER_TYPE_P (TREE_TYPE (callee)) + || (!type_noexcept_p (TREE_TYPE (TREE_TYPE (callee))) + && (callee_fn == NULL_TREE || !TREE_NOTHROW (callee_fn)))); } #if 0 @@ -9758,11 +11110,13 @@ struct check_for_return_continue_data { hash_set<tree> *pset; tree continue_stmt; tree break_stmt; + bool could_throw; }; /* Helper function for potential_constant_expression_1 SWITCH_STMT handling, called through cp_walk_tree. Return the first RETURN_EXPR found, or note - the first CONTINUE_STMT and/or BREAK_STMT if RETURN_EXPR is not found. */ + the first CONTINUE_STMT and/or BREAK_STMT if RETURN_EXPR is not found. + For C++26 also note presence of possibly throwing calls. */ static tree check_for_return_continue (tree *tp, int *walk_subtrees, void *data) { @@ -9847,6 +11201,13 @@ check_for_return_continue (tree *tp, int *walk_subtrees, void *data) case CONSTRUCTOR: break; + case AGGR_INIT_EXPR: + case CALL_EXPR: + /* In C++26 a function could throw. */ + if (callee_might_throw (t)) + d->could_throw = true; + break; + default: if (!EXPR_P (t)) *walk_subtrees = 0; @@ -10052,8 +11413,27 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, || TREE_CODE (t) != CALL_EXPR || current_function_decl == NULL_TREE || !is_std_construct_at (current_function_decl)) - && !cxx_dynamic_cast_fn_p (fun)) + && !cxx_dynamic_cast_fn_p (fun) + && !cxx_cxa_builtin_fn_p (fun)) { + /* In C++26 evaluation of the function arguments might + throw and in that case it is irrelevant whether + fun is constexpr or not. */ + if (cxx_dialect >= cxx26) + for (; i < nargs; ++i) + { + tree x = get_nth_callarg (t, i); + bool rv = processing_template_decl ? any : rval; + bool sub_now = false; + if (!potential_constant_expression_1 (x, rv, strict, + sub_now, + fundef_p, + flags, + jump_target)) + return false; + if (throws (jump_target)) + return true; + } if ((flags & tf_error) && constexpr_error (loc, fundef_p, "call to non-%<constexpr%> " @@ -10098,7 +11478,12 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, sub_now, fundef_p, flags, jump_target)) return false; + if (throws (jump_target)) + return true; } + /* In C++26 a function could throw. */ + if (*jump_target == NULL_TREE && callee_might_throw (t)) + *jump_target = void_node; return true; } @@ -10263,22 +11648,7 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, return true; case INDIRECT_REF: - { - tree x = TREE_OPERAND (t, 0); - STRIP_NOPS (x); - if (is_this_parameter (x) && !is_capture_proxy (x)) - { - if (now || !var_in_maybe_constexpr_fn (x)) - { - if (flags & tf_error) - constexpr_error (loc, fundef_p, "use of %<this%> in a " - "constant expression"); - return false; - } - return true; - } - return RECUR (x, rval); - } + return RECUR (TREE_OPERAND (t, 0), rval); case STATEMENT_LIST: for (tree stmt : tsi_range (t)) @@ -10336,11 +11706,13 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, a return. */ hash_set<tree> pset; check_for_return_continue_data data = { &pset, NULL_TREE, - NULL_TREE }; + NULL_TREE, false }; if (tree ret_expr = cp_walk_tree (&FOR_BODY (t), check_for_return_continue, &data, &pset)) *jump_target = ret_expr; + if (data.could_throw) + *jump_target = void_node; return true; } } @@ -10380,11 +11752,13 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, a return. */ hash_set<tree> pset; check_for_return_continue_data data = { &pset, NULL_TREE, - NULL_TREE }; + NULL_TREE, false }; if (tree ret_expr = cp_walk_tree (&WHILE_BODY (t), check_for_return_continue, &data, &pset)) *jump_target = ret_expr; + if (data.could_throw) + *jump_target = void_node; return true; } if (!RECUR (WHILE_BODY (t), any)) @@ -10408,7 +11782,7 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, { hash_set<tree> pset; check_for_return_continue_data data = { &pset, NULL_TREE, - NULL_TREE }; + NULL_TREE, false }; if (tree ret_expr = cp_walk_tree (&SWITCH_STMT_BODY (t), check_for_return_continue, &data, &pset)) @@ -10417,6 +11791,8 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, else if (data.continue_stmt) /* The switch can't return, but might continue. */ *jump_target = data.continue_stmt; + if (data.could_throw) + *jump_target = void_node; } return true; @@ -10446,7 +11822,6 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, case DYNAMIC_CAST_EXPR: case PSEUDO_DTOR_EXPR: - case THROW_EXPR: case OMP_PARALLEL: case OMP_TASK: case OMP_FOR: @@ -10497,6 +11872,16 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, "expression", t); return false; + case OMP_DECLARE_MAPPER: + /* This can be used to initialize VAR_DECLs: it's treated as a magic + constant. */ + return true; + + case THROW_EXPR: + if (cxx_dialect < cxx26) + goto fail; + return RECUR (TREE_OPERAND (t, 0), rval); + case ASM_EXPR: if (flags & tf_error) inline_asm_in_constexpr_error (loc, fundef_p); @@ -10625,6 +12010,22 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, case CLEANUP_POINT_EXPR: case MUST_NOT_THROW_EXPR: case TRY_CATCH_EXPR: + /* Even for C++26 handle TRY_BLOCK conservatively, if we detect the + body could throw, even with catch (...) among handlers we'd need + to analyze them in detail if they couldn't rethrow it. More + importantly though, throws (jump_target) is just conservative, + and there could be e.g. + try + { + possibly_throwing_fn (args); + break; + } + catch (...) + { + } + or continue or return instead of break. So, clearing *jump_target + because we see catch (...) handler might mean we missed break + etc. */ case TRY_BLOCK: case EH_SPEC_BLOCK: case EXPR_STMT: @@ -10866,9 +12267,9 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, want_rval, strict, now, fundef_p, tf_none, &this_jump_target)) { - if (returns (&this_jump_target)) + if (returns (&this_jump_target) || throws (&this_jump_target)) *jump_target = this_jump_target; - else if (!returns (jump_target)) + else if (!returns (jump_target) && !throws (jump_target)) { if (breaks (&this_jump_target) || continues (&this_jump_target)) @@ -10880,7 +12281,8 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, couldn't return, break or continue. */ hash_set<tree> pset; check_for_return_continue_data data = { &pset, NULL_TREE, - NULL_TREE }; + NULL_TREE, + false }; if (tree ret_expr = cp_walk_tree (&TREE_OPERAND (t, 2), check_for_return_continue, &data, @@ -10893,6 +12295,8 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, else if (data.break_stmt) *jump_target = data.break_stmt; } + if (data.could_throw) + *jump_target = void_node; } } return true; @@ -10944,6 +12348,9 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, *jump_target = *target; return true; } + if (DECL_ARTIFICIAL (*target)) + /* The user didn't write this goto, this isn't the problem. */ + return true; if (flags & tf_error) constexpr_error (loc, fundef_p, "%<goto%> is not a constant " "expression"); @@ -10977,6 +12384,9 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, case CO_AWAIT_EXPR: case CO_YIELD_EXPR: case CO_RETURN_EXPR: + if (flags & tf_error) + constexpr_error (cp_expr_loc_or_loc (t, input_location), fundef_p, + "%qE is not a constant expression", t); return false; /* Assume a TU-local entity is not constant, we'll error later when |