From ebebc928d8b0d17676e751848892f927373b1fe5 Mon Sep 17 00:00:00 2001 From: Alexandre Oliva Date: Thu, 4 Jul 2019 15:00:00 +0000 Subject: [PATCH] introduce EH_ELSE_EXPR tree and gimplifier I found GIMPLE_EH_ELSE offered exactly the semantics I needed for some Ada changes yet to be contributed, but GIMPLE_EH_ELSE was only built by GIMPLE passes, and I needed to build earlier something that eventually became GIMPLE_EH_ELSE. This patch does that, introducing an EH_ELSE_EXPR tree, and logic to dump it and to gimplify it. for gcc/ChangeLog * doc/generic.texi (Cleanups): Document EH_ELSE_EXPR. * except.c: Likewise. * expr.c (expand_expr_real_1): Reject it. * gimplify.c (gimplify_expr): Gimplify it, within TRY_FINALLY_EXPR. * tree-dump.c (dequeue_and_dump): Dump it. * tree-pretty-print.c (dump_generic_node): Likewise. * tree.c (block_may_fallthru): Handle it. * tree.def (EH_ELSE_EXPR): Introduce it. * gimple-pretty-print.c (dump_gimple_try): Dump TRY_FINALLY with GIMPLE_EH_ELSE as try/finally/else. From-SVN: r273084 --- gcc/ChangeLog | 14 ++++++++++++++ gcc/doc/generic.texi | 5 +++++ gcc/except.c | 12 ++++++------ gcc/expr.c | 1 + gcc/gimple-pretty-print.c | 20 +++++++++++++++++++- gcc/gimplify.c | 18 +++++++++++++++++- gcc/tree-dump.c | 1 + gcc/tree-pretty-print.c | 28 +++++++++++++++++++++++++--- gcc/tree.c | 3 +++ gcc/tree.def | 9 ++++++++- 10 files changed, 99 insertions(+), 12 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 19ab956a98c..41b8b14400a 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,17 @@ +2019-07-04 Alexandre Oliva + + * doc/generic.texi (Cleanups): Document EH_ELSE_EXPR. + * except.c: Likewise. + * expr.c (expand_expr_real_1): Reject it. + * gimplify.c (gimplify_expr): Gimplify it, within + TRY_FINALLY_EXPR. + * tree-dump.c (dequeue_and_dump): Dump it. + * tree-pretty-print.c (dump_generic_node): Likewise. + * tree.c (block_may_fallthru): Handle it. + * tree.def (EH_ELSE_EXPR): Introduce it. + * gimple-pretty-print.c (dump_gimple_try): Dump TRY_FINALLY + with GIMPLE_EH_ELSE as try/finally/else. + 2019-07-04 Richard Biener PR ipa/91062 diff --git a/gcc/doc/generic.texi b/gcc/doc/generic.texi index 67f7ad53af6..8901d5f357e 100644 --- a/gcc/doc/generic.texi +++ b/gcc/doc/generic.texi @@ -2180,6 +2180,11 @@ After the second sequence is executed, if it completes normally by falling off the end, execution continues wherever the first sequence would have continued, by falling off the end, or doing a goto, etc. +If the second sequence is an @code{EH_ELSE_EXPR} selector, then the +sequence in its first operand is used when the first sequence completes +normally, and that in its second operand is used for exceptional +cleanups, i.e., when an exception propagates out of the first sequence. + @code{TRY_FINALLY_EXPR} complicates the flow graph, since the cleanup needs to appear on every edge out of the controlled block; this reduces the freedom to move code across these edges. Therefore, the diff --git a/gcc/except.c b/gcc/except.c index edaeeb4cfd1..29f333912d1 100644 --- a/gcc/except.c +++ b/gcc/except.c @@ -27,14 +27,14 @@ along with GCC; see the file COPYING3. If not see the compilation process: In the beginning, in the front end, we have the GENERIC trees - TRY_CATCH_EXPR, TRY_FINALLY_EXPR, WITH_CLEANUP_EXPR, + TRY_CATCH_EXPR, TRY_FINALLY_EXPR, EH_ELSE_EXPR, WITH_CLEANUP_EXPR, CLEANUP_POINT_EXPR, CATCH_EXPR, and EH_FILTER_EXPR. - During initial gimplification (gimplify.c) these are lowered - to the GIMPLE_TRY, GIMPLE_CATCH, and GIMPLE_EH_FILTER nodes. - The WITH_CLEANUP_EXPR and CLEANUP_POINT_EXPR nodes are converted - into GIMPLE_TRY_FINALLY nodes; the others are a more direct 1-1 - conversion. + During initial gimplification (gimplify.c) these are lowered to the + GIMPLE_TRY, GIMPLE_CATCH, GIMPLE_EH_ELSE, and GIMPLE_EH_FILTER + nodes. The WITH_CLEANUP_EXPR and CLEANUP_POINT_EXPR nodes are + converted into GIMPLE_TRY_FINALLY nodes; the others are a more + direct 1-1 conversion. During pass_lower_eh (tree-eh.c) we record the nested structure of the TRY nodes in EH_REGION nodes in CFUN->EH->REGION_TREE. diff --git a/gcc/expr.c b/gcc/expr.c index 4acf250dd3c..c922aaa45b9 100644 --- a/gcc/expr.c +++ b/gcc/expr.c @@ -11292,6 +11292,7 @@ expand_expr_real_1 (tree exp, rtx target, machine_mode tmode, case CATCH_EXPR: case EH_FILTER_EXPR: case TRY_FINALLY_EXPR: + case EH_ELSE_EXPR: /* Lowered by tree-eh.c. */ gcc_unreachable (); diff --git a/gcc/gimple-pretty-print.c b/gcc/gimple-pretty-print.c index 45e7260e072..ce339eeddac 100644 --- a/gcc/gimple-pretty-print.c +++ b/gcc/gimple-pretty-print.c @@ -1232,6 +1232,8 @@ dump_gimple_try (pretty_printer *buffer, gtry *gs, int spc, newline_and_indent (buffer, spc + 2); pp_right_brace (buffer); + gimple_seq seq = gimple_try_cleanup (gs); + if (gimple_try_kind (gs) == GIMPLE_TRY_CATCH) { newline_and_indent (buffer, spc); @@ -1245,12 +1247,28 @@ dump_gimple_try (pretty_printer *buffer, gtry *gs, int spc, pp_string (buffer, "finally"); newline_and_indent (buffer, spc + 2); pp_left_brace (buffer); + + if (seq && is_a (gimple_seq_first_stmt (seq)) + && gimple_seq_nondebug_singleton_p (seq)) + { + geh_else *stmt = as_a (gimple_seq_first_stmt (seq)); + seq = gimple_eh_else_n_body (stmt); + pp_newline (buffer); + dump_gimple_seq (buffer, seq, spc + 4, flags); + newline_and_indent (buffer, spc + 2); + pp_right_brace (buffer); + seq = gimple_eh_else_e_body (stmt); + newline_and_indent (buffer, spc); + pp_string (buffer, "else"); + newline_and_indent (buffer, spc + 2); + pp_left_brace (buffer); + } } else pp_string (buffer, " {"); pp_newline (buffer); - dump_gimple_seq (buffer, gimple_try_cleanup (gs), spc + 4, flags); + dump_gimple_seq (buffer, seq, spc + 4, flags); newline_and_indent (buffer, spc + 2); pp_right_brace (buffer); } diff --git a/gcc/gimplify.c b/gcc/gimplify.c index 9e5e4230941..a3792d16742 100644 --- a/gcc/gimplify.c +++ b/gcc/gimplify.c @@ -13079,7 +13079,22 @@ gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p, input_location = UNKNOWN_LOCATION; eval = cleanup = NULL; gimplify_and_add (TREE_OPERAND (*expr_p, 0), &eval); - gimplify_and_add (TREE_OPERAND (*expr_p, 1), &cleanup); + if (TREE_CODE (*expr_p) == TRY_FINALLY_EXPR + && TREE_CODE (TREE_OPERAND (*expr_p, 1)) == EH_ELSE_EXPR) + { + gimple_seq n = NULL, e = NULL; + gimplify_and_add (TREE_OPERAND (TREE_OPERAND (*expr_p, 1), + 0), &n); + gimplify_and_add (TREE_OPERAND (TREE_OPERAND (*expr_p, 1), + 1), &e); + if (!gimple_seq_empty_p (n) && !gimple_seq_empty_p (e)) + { + geh_else *stmt = gimple_build_eh_else (n, e); + gimple_seq_add_stmt (&cleanup, stmt); + } + } + else + gimplify_and_add (TREE_OPERAND (*expr_p, 1), &cleanup); /* Don't create bogus GIMPLE_TRY with empty cleanup. */ if (gimple_seq_empty_p (cleanup)) { @@ -13637,6 +13652,7 @@ gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p, && code != LOOP_EXPR && code != SWITCH_EXPR && code != TRY_FINALLY_EXPR + && code != EH_ELSE_EXPR && code != OACC_PARALLEL && code != OACC_KERNELS && code != OACC_DATA diff --git a/gcc/tree-dump.c b/gcc/tree-dump.c index 58cb1ee5a72..51c0965861f 100644 --- a/gcc/tree-dump.c +++ b/gcc/tree-dump.c @@ -604,6 +604,7 @@ dequeue_and_dump (dump_info_p di) break; case TRY_FINALLY_EXPR: + case EH_ELSE_EXPR: dump_child ("op 0", TREE_OPERAND (t, 0)); dump_child ("op 1", TREE_OPERAND (t, 1)); break; diff --git a/gcc/tree-pretty-print.c b/gcc/tree-pretty-print.c index dacda7bd053..742c2840cd5 100644 --- a/gcc/tree-pretty-print.c +++ b/gcc/tree-pretty-print.c @@ -2815,12 +2815,34 @@ dump_generic_node (pretty_printer *pp, tree node, int spc, dump_flags_t flags, newline_and_indent (pp, spc+2); pp_right_brace (pp); newline_and_indent (pp, spc); - pp_string (pp, - (TREE_CODE (node) == TRY_CATCH_EXPR) ? "catch" : "finally"); + if (TREE_CODE (node) == TRY_CATCH_EXPR) + { + node = TREE_OPERAND (node, 1); + pp_string (pp, "catch"); + } + else + { + gcc_assert (TREE_CODE (node) == TRY_FINALLY_EXPR); + node = TREE_OPERAND (node, 1); + pp_string (pp, "finally"); + if (TREE_CODE (node) == EH_ELSE_EXPR) + { + newline_and_indent (pp, spc+2); + pp_left_brace (pp); + newline_and_indent (pp, spc+4); + dump_generic_node (pp, TREE_OPERAND (node, 0), spc+4, + flags, true); + newline_and_indent (pp, spc+2); + pp_right_brace (pp); + newline_and_indent (pp, spc); + node = TREE_OPERAND (node, 1); + pp_string (pp, "else"); + } + } newline_and_indent (pp, spc+2); pp_left_brace (pp); newline_and_indent (pp, spc+4); - dump_generic_node (pp, TREE_OPERAND (node, 1), spc+4, flags, true); + dump_generic_node (pp, node, spc+4, flags, true); newline_and_indent (pp, spc+2); pp_right_brace (pp); is_expr = false; diff --git a/gcc/tree.c b/gcc/tree.c index 76d94c6578a..563af6fbdda 100644 --- a/gcc/tree.c +++ b/gcc/tree.c @@ -13415,6 +13415,9 @@ block_may_fallthru (const_tree block) return (block_may_fallthru (TREE_OPERAND (stmt, 0)) && block_may_fallthru (TREE_OPERAND (stmt, 1))); + case EH_ELSE_EXPR: + return block_may_fallthru (TREE_OPERAND (stmt, 0)); + case MODIFY_EXPR: if (TREE_CODE (TREE_OPERAND (stmt, 1)) == CALL_EXPR) stmt = TREE_OPERAND (stmt, 1); diff --git a/gcc/tree.def b/gcc/tree.def index 10a14fc23b0..d2e693892cd 100644 --- a/gcc/tree.def +++ b/gcc/tree.def @@ -908,7 +908,14 @@ DEFTREECODE (TRY_CATCH_EXPR, "try_catch_expr", tcc_statement, 2) /* Evaluate the first operand. The second operand is a cleanup expression which is evaluated on any exit (normal, exception, or jump out) from this expression. */ -DEFTREECODE (TRY_FINALLY_EXPR, "try_finally", tcc_statement, 2) +DEFTREECODE (TRY_FINALLY_EXPR, "try_finally_expr", tcc_statement, 2) + +/* Evaluate either the normal or the exceptional cleanup. This must + only be present as the cleanup expression in a TRY_FINALLY_EXPR. + If the TRY_FINALLY_EXPR completes normally, the first operand of + EH_ELSE_EXPR is used as a cleanup, otherwise the second operand is + used. */ +DEFTREECODE (EH_ELSE_EXPR, "eh_else_expr", tcc_statement, 2) /* These types of expressions have no useful value, and always have side effects. */ -- 2.11.4.GIT