From 1b6fa695ab5e6f6fd57ed9264b336f06f440125b Mon Sep 17 00:00:00 2001 From: Martin Liska Date: Mon, 6 Nov 2017 10:02:15 +0100 Subject: [PATCH] Instrument function exit with __builtin_unreachable in C++ 2017-11-06 Martin Liska PR middle-end/82404 * c-opts.c (c_common_post_options): Set -Wreturn-type for C++ FE. * c.opt: Set default value of warn_return_type. 2017-11-06 Martin Liska PR middle-end/82404 * constexpr.c (cxx_eval_builtin_function_call): Handle __builtin_unreachable call. (get_function_named_in_call): Declare function earlier. (constexpr_fn_retval): Skip __builtin_unreachable. * cp-gimplify.c (cp_ubsan_maybe_instrument_return): Rename to ... (cp_maybe_instrument_return): ... this. (cp_genericize): Call the function unconditionally. 2017-11-06 Martin Liska PR middle-end/82404 * options.c (gfc_post_options): Set default value of -Wreturn-type to false. From-SVN: r254437 --- gcc/c-family/ChangeLog | 7 ++++++ gcc/c-family/c-opts.c | 3 +++ gcc/c-family/c.opt | 2 +- gcc/cp/ChangeLog | 12 ++++++++++ gcc/cp/constexpr.c | 52 ++++++++++++++++++++++++++++-------------- gcc/cp/cp-gimplify.c | 20 +++++++++++----- gcc/fortran/ChangeLog | 6 +++++ gcc/fortran/options.c | 3 +++ 8 files changed, 81 insertions(+), 24 deletions(-) diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog index e8476426fcb..373db2d1994 100644 --- a/gcc/c-family/ChangeLog +++ b/gcc/c-family/ChangeLog @@ -1,3 +1,10 @@ +2017-11-06 Martin Liska + + PR middle-end/82404 + * c-opts.c (c_common_post_options): Set -Wreturn-type for C++ + FE. + * c.opt: Set default value of warn_return_type. + 2017-10-31 David Malcolm * c-common.c (binary_op_error): Update for renaming of diff --git a/gcc/c-family/c-opts.c b/gcc/c-family/c-opts.c index 32120e636c2..cead15e7a63 100644 --- a/gcc/c-family/c-opts.c +++ b/gcc/c-family/c-opts.c @@ -989,6 +989,9 @@ c_common_post_options (const char **pfilename) flag_extern_tls_init = 1; } + if (warn_return_type == -1) + warn_return_type = c_dialect_cxx (); + if (num_in_fnames > 1) error ("too many filenames given. Type %s --help for usage", progname); diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt index dae124ac1c2..9ab31f0e153 100644 --- a/gcc/c-family/c.opt +++ b/gcc/c-family/c.opt @@ -960,7 +960,7 @@ C++ ObjC++ Var(warn_reorder) Warning LangEnabledBy(C++ ObjC++,Wall) Warn when the compiler reorders code. Wreturn-type -C ObjC C++ ObjC++ Var(warn_return_type) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall) +C ObjC C++ ObjC++ Var(warn_return_type) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall) Init(-1) Warn whenever a function's return type defaults to \"int\" (C), or about inconsistent return types (C++). Wscalar-storage-order diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 590e3221c8c..bb90b5ac4da 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,15 @@ +2017-11-06 Martin Liska + + PR middle-end/82404 + * constexpr.c (cxx_eval_builtin_function_call): Handle + __builtin_unreachable call. + (get_function_named_in_call): Declare function earlier. + (constexpr_fn_retval): Skip __builtin_unreachable. + * cp-gimplify.c (cp_ubsan_maybe_instrument_return): Rename to + ... + (cp_maybe_instrument_return): ... this. + (cp_genericize): Call the function unconditionally. + 2017-11-03 Nathan Sidwell PR c++/82710 diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c index 483f731a49a..670aae22dd6 100644 --- a/gcc/cp/constexpr.c +++ b/gcc/cp/constexpr.c @@ -628,6 +628,20 @@ build_constexpr_constructor_member_initializers (tree type, tree body) return error_mark_node; } +/* We have an expression tree T that represents a call, either CALL_EXPR + or AGGR_INIT_EXPR. If the call is lexically to a named function, + retrun the _DECL for that function. */ + +static tree +get_function_named_in_call (tree t) +{ + tree fun = cp_get_callee (t); + if (fun && TREE_CODE (fun) == ADDR_EXPR + && TREE_CODE (TREE_OPERAND (fun, 0)) == FUNCTION_DECL) + fun = TREE_OPERAND (fun, 0); + return fun; +} + /* Subroutine of register_constexpr_fundef. BODY is the body of a function declared to be constexpr, or a sub-statement thereof. Returns the return value if suitable, error_mark_node for a statement not allowed in @@ -682,6 +696,15 @@ constexpr_fn_retval (tree body) case USING_STMT: return NULL_TREE; + case CALL_EXPR: + { + tree fun = get_function_named_in_call (body); + if (fun != NULL_TREE + && DECL_FUNCTION_CODE (fun) == BUILT_IN_UNREACHABLE) + return NULL_TREE; + } + /* Fallthru. */ + default: return error_mark_node; } @@ -1097,20 +1120,6 @@ save_fundef_copy (tree fun, tree copy) *slot = copy; } -/* We have an expression tree T that represents a call, either CALL_EXPR - or AGGR_INIT_EXPR. If the call is lexically to a named function, - retrun the _DECL for that function. */ - -static tree -get_function_named_in_call (tree t) -{ - tree fun = cp_get_callee (t); - if (fun && TREE_CODE (fun) == ADDR_EXPR - && TREE_CODE (TREE_OPERAND (fun, 0)) == FUNCTION_DECL) - fun = TREE_OPERAND (fun, 0); - return fun; -} - /* We have an expression tree T that represents a call, either CALL_EXPR or AGGR_INIT_EXPR. Return the Nth argument. */ @@ -1180,9 +1189,18 @@ cxx_eval_builtin_function_call (const constexpr_ctx *ctx, tree t, tree fun, { if (!*non_constant_p && !ctx->quiet) { - new_call = build_call_array_loc (EXPR_LOCATION (t), TREE_TYPE (t), - CALL_EXPR_FN (t), nargs, args); - error ("%q+E is not a constant expression", new_call); + /* Do not allow__builtin_unreachable in constexpr function. + The __builtin_unreachable call with BUILTINS_LOCATION + comes from cp_maybe_instrument_return. */ + if (DECL_FUNCTION_CODE (fun) == BUILT_IN_UNREACHABLE + && EXPR_LOCATION (t) == BUILTINS_LOCATION) + error ("constexpr call flows off the end of the function"); + else + { + new_call = build_call_array_loc (EXPR_LOCATION (t), TREE_TYPE (t), + CALL_EXPR_FN (t), nargs, args); + error ("%q+E is not a constant expression", new_call); + } } *non_constant_p = true; return t; diff --git a/gcc/cp/cp-gimplify.c b/gcc/cp/cp-gimplify.c index 262485a5c1f..014c1ee7231 100644 --- a/gcc/cp/cp-gimplify.c +++ b/gcc/cp/cp-gimplify.c @@ -1556,10 +1556,11 @@ cp_genericize_tree (tree* t_p, bool handle_invisiref_parm_p) /* If a function that should end with a return in non-void function doesn't obviously end with return, add ubsan - instrumentation code to verify it at runtime. */ + instrumentation code to verify it at runtime. If -fsanitize=return + is not enabled, instrument __builtin_unreachable. */ static void -cp_ubsan_maybe_instrument_return (tree fndecl) +cp_maybe_instrument_return (tree fndecl) { if (VOID_TYPE_P (TREE_TYPE (TREE_TYPE (fndecl))) || DECL_CONSTRUCTOR_P (fndecl) @@ -1600,7 +1601,16 @@ cp_ubsan_maybe_instrument_return (tree fndecl) tree *p = &DECL_SAVED_TREE (fndecl); if (TREE_CODE (*p) == BIND_EXPR) p = &BIND_EXPR_BODY (*p); - t = ubsan_instrument_return (DECL_SOURCE_LOCATION (fndecl)); + + location_t loc = DECL_SOURCE_LOCATION (fndecl); + if (sanitize_flags_p (SANITIZE_RETURN, fndecl)) + t = ubsan_instrument_return (loc); + else + { + tree fndecl = builtin_decl_explicit (BUILT_IN_UNREACHABLE); + t = build_call_expr_loc (BUILTINS_LOCATION, fndecl, 0); + } + append_to_statement_list (t, p); } @@ -1674,9 +1684,7 @@ cp_genericize (tree fndecl) walk_tree's hash functionality. */ cp_genericize_tree (&DECL_SAVED_TREE (fndecl), true); - if (sanitize_flags_p (SANITIZE_RETURN) - && current_function_decl != NULL_TREE) - cp_ubsan_maybe_instrument_return (fndecl); + cp_maybe_instrument_return (fndecl); /* Do everything else. */ c_genericize (fndecl); diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog index 58ee3e50237..1e403366656 100644 --- a/gcc/fortran/ChangeLog +++ b/gcc/fortran/ChangeLog @@ -1,3 +1,9 @@ +2017-11-06 Martin Liska + + PR middle-end/82404 + * options.c (gfc_post_options): Set default value of + -Wreturn-type to false. + 2017-11-05 Thomas Koenig PR fortran/82471 diff --git a/gcc/fortran/options.c b/gcc/fortran/options.c index 0ee6b7808d9..c584a19e559 100644 --- a/gcc/fortran/options.c +++ b/gcc/fortran/options.c @@ -435,6 +435,9 @@ gfc_post_options (const char **pfilename) gfc_fatal_error ("Maximum subrecord length cannot exceed %d", MAX_SUBRECORD_LENGTH); + if (warn_return_type == -1) + warn_return_type = 0; + gfc_cpp_post_options (); if (gfc_option.allow_std & GFC_STD_F2008) -- 2.30.2