From 6436add49ed9ecf74f1f01b4fe18961df4f3e83d Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Mon, 13 Feb 2023 10:41:51 +0100 Subject: [PATCH] tree-optimization/108691 - indirect calls to setjmp DCE now chokes on indirect setjmp calls becoming direct because that exposes them too late to be subject to abnormal edge creation. The following patch honors gimple_call_ctrl_altering for those and _not_ treat formerly indirect calls to setjmp as calls to setjmp in notice_special_calls. Unfortunately there's no way to have an indirect call to setjmp properly annotated (the returns_twice attribute is ignored on types). RTL expansion late discovers returns-twice for the purpose of adding REG_SETJMP notes and also sets ->calls_setjmp (instead of asserting it is set). There's no good way to transfer proper knowledge around here so I'm using ->calls_setjmp as a flag to indicate whether gimple_call_ctrl_altering_p was set. PR tree-optimization/108691 * tree-cfg.cc (notice_special_calls): When the CFG is built honor gimple_call_ctrl_altering_p. * cfgexpand.cc (expand_call_stmt): Clear cfun->calls_setjmp temporarily if the call is not control-altering. * calls.cc (emit_call_1): Do not add REG_SETJMP if cfun->calls_setjmp is not set. Do not alter cfun->calls_setjmp. * gcc.dg/pr108691.c: New testcase. --- gcc/calls.cc | 10 +++++----- gcc/cfgexpand.cc | 7 +++++++ gcc/testsuite/gcc.dg/pr108691.c | 9 +++++++++ gcc/tree-cfg.cc | 4 +++- 4 files changed, 24 insertions(+), 6 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/pr108691.c diff --git a/gcc/calls.cc b/gcc/calls.cc index 4d7f6c3d2912..0242d52cfb35 100644 --- a/gcc/calls.cc +++ b/gcc/calls.cc @@ -506,11 +506,11 @@ emit_call_1 (rtx funexp, tree fntree ATTRIBUTE_UNUSED, tree fndecl ATTRIBUTE_UNU if (ecf_flags & ECF_NORETURN) add_reg_note (call_insn, REG_NORETURN, const0_rtx); - if (ecf_flags & ECF_RETURNS_TWICE) - { - add_reg_note (call_insn, REG_SETJMP, const0_rtx); - cfun->calls_setjmp = 1; - } + if (ecf_flags & ECF_RETURNS_TWICE + /* We rely on GIMPLE setting this flag and here use it to + catch formerly indirect and not control-altering calls. */ + && cfun->calls_setjmp) + add_reg_note (call_insn, REG_SETJMP, const0_rtx); SIBLING_CALL_P (call_insn) = ((ecf_flags & ECF_SIBCALL) != 0); diff --git a/gcc/cfgexpand.cc b/gcc/cfgexpand.cc index 25b1558dcb94..ab143a6d2d3d 100644 --- a/gcc/cfgexpand.cc +++ b/gcc/cfgexpand.cc @@ -2808,6 +2808,11 @@ expand_call_stmt (gcall *stmt) /* Must come after copying location. */ copy_warning (exp, stmt); + /* For calls that do not alter control flow avoid REG_SETJMP notes. */ + bool saved_calls_setjmp = cfun->calls_setjmp; + if (!gimple_call_ctrl_altering_p (stmt)) + cfun->calls_setjmp = false; + /* Ensure RTL is created for debug args. */ if (decl && DECL_HAS_DEBUG_ARGS_P (decl)) { @@ -2846,6 +2851,8 @@ expand_call_stmt (gcall *stmt) } mark_transaction_restart_calls (stmt); + + cfun->calls_setjmp = saved_calls_setjmp; } diff --git a/gcc/testsuite/gcc.dg/pr108691.c b/gcc/testsuite/gcc.dg/pr108691.c new file mode 100644 index 000000000000..e412df10f22c --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr108691.c @@ -0,0 +1,9 @@ +/* { dg-do compile } */ +/* { dg-options "-O2" } */ + +extern int __attribute__((returns_twice)) setjmp(void*); + +void bbb(void) { + int (*fnptr)(void*) = setjmp; + fnptr(0); +} diff --git a/gcc/tree-cfg.cc b/gcc/tree-cfg.cc index a9fcc7fd050f..e23293e5cd1f 100644 --- a/gcc/tree-cfg.cc +++ b/gcc/tree-cfg.cc @@ -2280,7 +2280,9 @@ notice_special_calls (gcall *call) if (flags & ECF_MAY_BE_ALLOCA) cfun->calls_alloca = true; - if (flags & ECF_RETURNS_TWICE) + if (flags & ECF_RETURNS_TWICE + && (!(cfun->curr_properties & PROP_cfg) + || gimple_call_ctrl_altering_p (call))) cfun->calls_setjmp = true; } -- 2.47.2