From b847405adee3059762816ab009bc4a5281b5b911 Mon Sep 17 00:00:00 2001 From: Alexandre Oliva Date: Fri, 12 Jul 2019 13:51:00 +0000 Subject: [PATCH] allow EH to escape from GIMPLE_EH_ELSE ELSE block The only preexisting use of GIMPLE_EH_ELSE, for transactional memory commits, did not allow exceptions to escape from the ELSE path. The trick it uses to allow the ELSE path to see the propagating exception does not work very well if the exception cleanup raises further exceptions: the ELSE block is configured to handle exceptions in itself. This confuses the heck out of CFG and EH cleanups. Basing the lowering context for the ELSE block on outer_state, rather than this_state, gets us the expected enclosing handler. for gcc/ChangeLog * tree-eh.c (honor_protect_cleanup_actions): Use outer_ rather than this_state as the lowering context for the ELSE seq in a GIMPLE_EH_ELSE. for gcc/testsuite/ChangeLog * gcc.dg/gimplefe-44.c: New. From-SVN: r273444 --- gcc/ChangeLog | 6 ++++++ gcc/testsuite/ChangeLog | 2 ++ gcc/testsuite/gcc.dg/gimplefe-44.c | 33 ++++++++++++++++++++++++++++++ gcc/tree-eh.c | 13 +++++++----- 4 files changed, 49 insertions(+), 5 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/gimplefe-44.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 43b52489921..2d1d29f005c 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2019-07-12 Alexandre Oliva + + * tree-eh.c (honor_protect_cleanup_actions): Use outer_ + rather than this_state as the lowering context for the ELSE + seq in a GIMPLE_EH_ELSE. + 2019-07-12 Richard Sandiford * vector-builder.h (vector_builder::elt): Allow already-supplied diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index c2352005a37..debec92a89f 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,5 +1,7 @@ 2019-07-12 Alexandre Oliva + * gcc.dg/gimplefe-44.c: New. + * gcc.dg/gimplefe-43.c: New. 2019-07-12 Richard Biener diff --git a/gcc/testsuite/gcc.dg/gimplefe-44.c b/gcc/testsuite/gcc.dg/gimplefe-44.c new file mode 100644 index 00000000000..a9a92b1701e --- /dev/null +++ b/gcc/testsuite/gcc.dg/gimplefe-44.c @@ -0,0 +1,33 @@ +/* { dg-do compile } */ +/* { dg-options "-fexceptions -fgimple -fdump-tree-eh-eh" } */ + +void __GIMPLE foo() +{ + try + { + try + { + extern void might_throw1 (); + might_throw1 (); + } + finally + { + extern void might_throw2 (); + might_throw2 (); + } + else + { + extern void might_throw3 (); + might_throw3 (); + } + } + finally + { + extern void might_throw4 (); + might_throw4 (); + } +} + +/* { dg-final { scan-tree-dump ".LP 1. might_throw1" "eh" } } */ +/* { dg-final { scan-tree-dump ".LP 2. might_throw2" "eh" } } */ +/* { dg-final { scan-tree-dump ".LP 2. might_throw3" "eh" } } */ diff --git a/gcc/tree-eh.c b/gcc/tree-eh.c index fb7d202fc6f..5bb07e49d28 100644 --- a/gcc/tree-eh.c +++ b/gcc/tree-eh.c @@ -996,11 +996,14 @@ honor_protect_cleanup_actions (struct leh_state *outer_state, gimple_try_set_cleanup (tf->top_p, gimple_eh_else_n_body (eh_else)); finally = gimple_eh_else_e_body (eh_else); - /* Let the ELSE see the exception that's being processed. */ - eh_region save_ehp = this_state->ehp_region; - this_state->ehp_region = this_state->cur_region; - lower_eh_constructs_1 (this_state, &finally); - this_state->ehp_region = save_ehp; + /* Let the ELSE see the exception that's being processed, but + since the cleanup is outside the try block, process it with + outer_state, otherwise it may be used as a cleanup for + itself, and Bad Things (TM) ensue. */ + eh_region save_ehp = outer_state->ehp_region; + outer_state->ehp_region = this_state->cur_region; + lower_eh_constructs_1 (outer_state, &finally); + outer_state->ehp_region = save_ehp; } else { -- 2.30.2