diff options
Diffstat (limited to 'gcc/cp/semantics.cc')
| -rw-r--r-- | gcc/cp/semantics.cc | 47 |
1 files changed, 46 insertions, 1 deletions
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc index 52044be..a0f2edc 100644 --- a/gcc/cp/semantics.cc +++ b/gcc/cp/semantics.cc @@ -4982,6 +4982,7 @@ public: tree result; hash_table<nofree_ptr_hash <tree_node> > visited; bool simple; + bool in_nrv_cleanup; }; /* Helper function for walk_tree, used by finalize_nrv below. */ @@ -4997,7 +4998,7 @@ finalize_nrv_r (tree* tp, int* walk_subtrees, void* data) if (TYPE_P (*tp)) *walk_subtrees = 0; /* If there's a label, we might need to destroy the NRV on goto (92407). */ - else if (TREE_CODE (*tp) == LABEL_EXPR) + else if (TREE_CODE (*tp) == LABEL_EXPR && !dp->in_nrv_cleanup) dp->simple = false; /* Change NRV returns to just refer to the RESULT_DECL; this is a nop, but differs from using NULL_TREE in that it indicates that we care @@ -5016,16 +5017,59 @@ finalize_nrv_r (tree* tp, int* walk_subtrees, void* data) else if (TREE_CODE (*tp) == CLEANUP_STMT && CLEANUP_DECL (*tp) == dp->var) { + dp->in_nrv_cleanup = true; + cp_walk_tree (&CLEANUP_BODY (*tp), finalize_nrv_r, data, 0); + dp->in_nrv_cleanup = false; + cp_walk_tree (&CLEANUP_EXPR (*tp), finalize_nrv_r, data, 0); + *walk_subtrees = 0; + if (dp->simple) + /* For a simple NRV, just run it on the EH path. */ CLEANUP_EH_ONLY (*tp) = true; else { + /* Not simple, we need to check current_retval_sentinel to decide + whether to run it. If it's set, we're returning normally and + don't want to destroy the NRV. If the sentinel is not set, we're + leaving scope some other way, either by flowing off the end of its + scope or throwing an exception. */ tree cond = build3 (COND_EXPR, void_type_node, current_retval_sentinel, void_node, CLEANUP_EXPR (*tp)); CLEANUP_EXPR (*tp) = cond; } + + /* If a cleanup might throw, we need to clear current_retval_sentinel on + the exception path, both so the check above succeeds and so an outer + cleanup added by maybe_splice_retval_cleanup doesn't run. */ + if (cp_function_chain->throwing_cleanup) + { + tree clear = build2 (MODIFY_EXPR, boolean_type_node, + current_retval_sentinel, + boolean_false_node); + if (dp->simple) + { + /* We're already only on the EH path, just prepend it. */ + tree &exp = CLEANUP_EXPR (*tp); + exp = build2 (COMPOUND_EXPR, void_type_node, clear, exp); + } + else + { + /* The cleanup runs on both normal and EH paths, we need another + CLEANUP_STMT to clear the flag only on the EH path. */ + tree &bod = CLEANUP_BODY (*tp); + bod = build_stmt (EXPR_LOCATION (*tp), CLEANUP_STMT, + bod, clear, current_retval_sentinel); + CLEANUP_EH_ONLY (bod) = true; + } + } } + /* Disable maybe_splice_retval_cleanup within the NRV cleanup scope, we don't + want to destroy the retval before the variable goes out of scope. */ + else if (TREE_CODE (*tp) == CLEANUP_STMT + && dp->in_nrv_cleanup + && CLEANUP_DECL (*tp) == dp->result) + CLEANUP_EXPR (*tp) = void_node; /* Replace the DECL_EXPR for the NRV with an initialization of the RESULT_DECL, if needed. */ else if (TREE_CODE (*tp) == DECL_EXPR @@ -5082,6 +5126,7 @@ finalize_nrv (tree fndecl, tree var) data.var = var; data.result = result; + data.in_nrv_cleanup = false; /* This is simpler for variables declared in the outer scope of the function so we know that their lifetime always ends with a |