diff options
Diffstat (limited to 'gcc/cp/constexpr.c')
| -rw-r--r-- | gcc/cp/constexpr.c | 85 |
1 files changed, 74 insertions, 11 deletions
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c index c92db5d..69d9d3d 100644 --- a/gcc/cp/constexpr.c +++ b/gcc/cp/constexpr.c @@ -37,6 +37,8 @@ along with GCC; see the file COPYING3. If not see #include "stor-layout.h" #include "cgraph.h" #include "opts.h" +#include "stringpool.h" +#include "attribs.h" static bool verify_constant (tree, bool, bool *, bool *); #define VERIFY_CONSTANT(X) \ @@ -220,6 +222,17 @@ is_valid_constexpr_fn (tree fun, bool complain) inform (DECL_SOURCE_LOCATION (fun), "lambdas are implicitly %<constexpr%> only in C++17 and later"); } + else if (DECL_DESTRUCTOR_P (fun)) + { + if (cxx_dialect < cxx20) + { + ret = false; + if (complain) + error_at (DECL_SOURCE_LOCATION (fun), + "%<constexpr%> destructors only available" + " with %<-std=c++20%> or %<-std=gnu++20%>"); + } + } else if (!DECL_CONSTRUCTOR_P (fun)) { tree rettype = TREE_TYPE (TREE_TYPE (fun)); @@ -865,12 +878,31 @@ void maybe_save_constexpr_fundef (tree fun) { if (processing_template_decl - || !DECL_DECLARED_CONSTEXPR_P (fun) || cp_function_chain->invalid_constexpr || (DECL_CLONED_FUNCTION_P (fun) && !DECL_DELETING_DESTRUCTOR_P (fun))) return; - bool complain = !DECL_GENERATED_P (fun); + /* With -fimplicit-constexpr, try to make inlines constexpr. We'll + actually set DECL_DECLARED_CONSTEXPR_P below if the checks pass. */ + bool implicit = false; + if (flag_implicit_constexpr) + { + if (DECL_DELETING_DESTRUCTOR_P (fun) + && decl_implicit_constexpr_p (DECL_CLONED_FUNCTION (fun))) + /* Don't inherit implicit constexpr from the non-deleting + destructor. */ + DECL_DECLARED_CONSTEXPR_P (fun) = false; + + if (!DECL_DECLARED_CONSTEXPR_P (fun) + && DECL_DECLARED_INLINE_P (fun) + && !lookup_attribute ("noinline", DECL_ATTRIBUTES (fun))) + implicit = true; + } + + if (!DECL_DECLARED_CONSTEXPR_P (fun) && !implicit) + return; + + bool complain = !DECL_GENERATED_P (fun) && !implicit; if (!is_valid_constexpr_fn (fun, complain)) return; @@ -878,7 +910,7 @@ maybe_save_constexpr_fundef (tree fun) tree massaged = massage_constexpr_body (fun, DECL_SAVED_TREE (fun)); if (massaged == NULL_TREE || massaged == error_mark_node) { - if (!DECL_CONSTRUCTOR_P (fun)) + if (!DECL_CONSTRUCTOR_P (fun) && complain) error ("body of %<constexpr%> function %qD not a return-statement", fun); return; @@ -907,6 +939,21 @@ maybe_save_constexpr_fundef (tree fun) if (!potential && complain) return; + if (implicit) + { + if (potential) + { + DECL_DECLARED_CONSTEXPR_P (fun) = true; + DECL_LANG_SPECIFIC (fun)->u.fn.implicit_constexpr = true; + if (DECL_CONSTRUCTOR_P (fun)) + TYPE_HAS_CONSTEXPR_CTOR (DECL_CONTEXT (fun)) = true; + } + else + /* Don't bother keeping the pre-generic body of unsuitable functions + not explicitly declared constexpr. */ + return; + } + constexpr_fundef entry = {fun, NULL_TREE, NULL_TREE, NULL_TREE}; bool clear_ctx = false; if (DECL_RESULT (fun) && DECL_CONTEXT (DECL_RESULT (fun)) == NULL_TREE) @@ -2404,7 +2451,7 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, lval, non_constant_p, overflow_p); if (DECL_THUNK_P (fun)) return cxx_eval_thunk_call (ctx, t, fun, lval, non_constant_p, overflow_p); - if (!DECL_DECLARED_CONSTEXPR_P (fun)) + if (!maybe_constexpr_fn (fun)) { if (TREE_CODE (t) == CALL_EXPR && cxx_replaceable_global_alloc_fn (fun) @@ -5229,7 +5276,9 @@ bool maybe_constexpr_fn (tree t) { return (DECL_DECLARED_CONSTEXPR_P (t) - || (cxx_dialect >= cxx17 && LAMBDA_FUNCTION_P (t))); + || (cxx_dialect >= cxx17 && LAMBDA_FUNCTION_P (t)) + || (flag_implicit_constexpr + && DECL_DECLARED_INLINE_P (STRIP_TEMPLATE (t)))); } /* True if T was declared in a function that might be constexpr: either a @@ -5238,11 +5287,8 @@ maybe_constexpr_fn (tree t) bool var_in_maybe_constexpr_fn (tree t) { - if (cxx_dialect >= cxx17 - && DECL_FUNCTION_SCOPE_P (t) - && LAMBDA_FUNCTION_P (DECL_CONTEXT (t))) - return true; - return var_in_constexpr_fn (t); + return (DECL_FUNCTION_SCOPE_P (t) + && maybe_constexpr_fn (DECL_CONTEXT (t))); } /* We're assigning INIT to TARGET. In do_build_copy_constructor and @@ -8219,7 +8265,7 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, { if (builtin_valid_in_constant_expr_p (fun)) return true; - if (!DECL_DECLARED_CONSTEXPR_P (fun) + if (!maybe_constexpr_fn (fun) /* Allow any built-in function; if the expansion isn't constant, we'll deal with that then. */ && !fndecl_built_in_p (fun) @@ -9257,6 +9303,23 @@ is_nondependent_static_init_expression (tree t) && !instantiation_dependent_expression_p (t)); } +/* True iff FN is an implicitly constexpr function. */ + +bool +decl_implicit_constexpr_p (tree fn) +{ + if (!(flag_implicit_constexpr + && TREE_CODE (fn) == FUNCTION_DECL + && DECL_DECLARED_CONSTEXPR_P (fn))) + return false; + + if (DECL_CLONED_FUNCTION_P (fn)) + fn = DECL_CLONED_FUNCTION (fn); + + return (DECL_LANG_SPECIFIC (fn) + && DECL_LANG_SPECIFIC (fn)->u.fn.implicit_constexpr); +} + /* Finalize constexpr processing after parsing. */ void |