From patchwork Mon Apr 29 08:09:32 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lulu Cheng X-Patchwork-Id: 1928862 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org (client-ip=2620:52:3:1:0:246e:9693:128c; helo=server2.sourceware.org; envelope-from=gcc-patches-bounces+incoming=patchwork.ozlabs.org@gcc.gnu.org; receiver=patchwork.ozlabs.org) Received: from server2.sourceware.org (server2.sourceware.org [IPv6:2620:52:3:1:0:246e:9693:128c]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1) server-digest SHA384) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4VSbdP3VB8z23hd for ; Mon, 29 Apr 2024 18:11:37 +1000 (AEST) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 897193858C31 for ; Mon, 29 Apr 2024 08:11:35 +0000 (GMT) X-Original-To: gcc-patches@gcc.gnu.org Delivered-To: gcc-patches@gcc.gnu.org Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by sourceware.org (Postfix) with ESMTP id 76A243858D33 for ; Mon, 29 Apr 2024 08:09:45 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 76A243858D33 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=loongson.cn Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=loongson.cn ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 76A243858D33 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=114.242.206.163 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1714378189; cv=none; b=iVgUpMwT9RClhECFcLmt2EC0a0NY80Tm3817oKI+rlp5HFqG4nnYaftFgWUp6dtAHEnTf49P+b4YEJDILnFYZyxLIUfLWB/J+rWTktJqO+ro9n3md52F3gScrC5KMbP+aaPSjMuxkDIBMHR429GBXr+XO3TYtkZMDLWtXUfqWLY= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1714378189; c=relaxed/simple; bh=SUicUq9JT2j/SoUJyM620hiK+7DerAj9Bd11cUVBTRI=; h=From:To:Subject:Date:Message-Id:MIME-Version; b=j463+nJrA7ehOYkPMgR42Zr1UwM526LsKXe5f+OSqi8xU8V5efl7aA7pivDUscZItmM03NAMICNKRUisiqowLh5HuKTJhCGorC3Ml450k0Uc1P7MjOx2PDCAjYwlQeo5hystMEUSvNWpxhTX6BWo+oiaU5RsyPVsVU8WN6RaaKw= ARC-Authentication-Results: i=1; server2.sourceware.org Received: from loongson.cn (unknown [10.20.4.107]) by gateway (Coremail) with SMTP id _____8CxZ_DFVS9mRdgEAA--.16814S3; Mon, 29 Apr 2024 16:09:41 +0800 (CST) Received: from loongson-pc.loongson.cn (unknown [10.20.4.107]) by localhost.localdomain (Coremail) with SMTP id AQAAf8AxQ1bDVS9m3eUJAA--.7820S2; Mon, 29 Apr 2024 16:09:40 +0800 (CST) From: Lulu Cheng To: gcc-patches@gcc.gnu.org Cc: xry111@xry111.site, i@xen0n.name, xuchenghua@loongson.cn, chenglulu@loongson.cn, Yang Yujie Subject: [PATCH][gcc-12] LoongArch: Fix eh_return epilogue for normal returns. Date: Mon, 29 Apr 2024 16:09:32 +0800 Message-Id: <20240429080931.32560-1-chenglulu@loongson.cn> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 X-CM-TRANSID: AQAAf8AxQ1bDVS9m3eUJAA--.7820S2 X-CM-SenderInfo: xfkh0wpoxo3qxorr0wxvrqhubq/ X-Coremail-Antispam: 1Uk129KBj93XoW3XryrKw4DKw1xKryUCr1xWFX_yoW3Xr4Dpr Z7Zr93Ar48JwnxGryDJ343XFn5ArZ2gw12v3W3t3yxCw47Zr9xZF1xtF9FqF18tw48ur1I qF4kJa1Y93WUG3cCm3ZEXasCq-sJn29KB7ZKAUJUUUUU529EdanIXcx71UUUUU7KY7ZEXa sCq-sGcSsGvfJ3Ic02F40EFcxC0VAKzVAqx4xG6I80ebIjqfuFe4nvWSU5nxnvy29KBjDU 0xBIdaVrnRJUUUkFb4IE77IF4wAFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2 IYs7xG6rWj6s0DM7CIcVAFz4kK6r106r15M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_JFI_Gr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Jr0_Gr1l84ACjcxK6I8E87Iv67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVCY1x0267AK xVW8Jr0_Cr1UM2AIxVAIcxkEcVAq07x20xvEncxIr21l57IF6xkI12xvs2x26I8E6xACxx 1l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv 67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41l42xK82IYc2 Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s02 6x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r126r1DMIIYrxkI7VAKI48JMIIF0x vE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r1j6r4UMIIF0xvE 42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6x kF7I0E14v26r1j6r4UYxBIdaVFxhVjvjDU0xZFpf9x07j8yCJUUUUU= X-Spam-Status: No, score=-12.6 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, KAM_SHORT, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: gcc-patches-bounces+incoming=patchwork.ozlabs.org@gcc.gnu.org From: Yang Yujie On LoongArch, the regitsters $r4 - $r7 (EH_RETURN_DATA_REGNO) will be saved and restored in the function prologue and epilogue if the given function calls __builtin_eh_return. This causes the return value to be overwritten on normal return paths and breaks a rare case of libgcc's _Unwind_RaiseException. gcc/ChangeLog: PR target/114848 * config/loongarch/loongarch.cc: Do not restore the saved eh_return data registers ($r4-$r7) for a normal return of a function that calls __builtin_eh_return elsewhere. * config/loongarch/loongarch-protos.h: Same. * config/loongarch/loongarch.md: Same. gcc/testsuite/ChangeLog: * gcc.target/loongarch/eh_return-normal-return.c: New test. (cherry picked from commit 4b421728289e6f1caa0dfaa953a11698ab95d37d) --- gcc/config/loongarch/loongarch-protos.h | 2 +- gcc/config/loongarch/loongarch.cc | 35 ++++++++++++----- gcc/config/loongarch/loongarch.md | 23 ++++++++++- .../loongarch/eh_return-normal-return.c | 38 +++++++++++++++++++ 4 files changed, 85 insertions(+), 13 deletions(-) create mode 100644 gcc/testsuite/gcc.target/loongarch/eh_return-normal-return.c diff --git a/gcc/config/loongarch/loongarch-protos.h b/gcc/config/loongarch/loongarch-protos.h index 2144c2421ed..8af82ffaa20 100644 --- a/gcc/config/loongarch/loongarch-protos.h +++ b/gcc/config/loongarch/loongarch-protos.h @@ -47,7 +47,7 @@ enum loongarch_symbol_type { extern rtx loongarch_emit_move (rtx, rtx); extern HOST_WIDE_INT loongarch_initial_elimination_offset (int, int); extern void loongarch_expand_prologue (void); -extern void loongarch_expand_epilogue (bool); +extern void loongarch_expand_epilogue (int); extern bool loongarch_can_use_return_insn (void); extern bool loongarch_symbolic_constant_p (rtx, enum loongarch_symbol_type *); diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc index 33b1919e7a3..a0e11f2fc66 100644 --- a/gcc/config/loongarch/loongarch.cc +++ b/gcc/config/loongarch/loongarch.cc @@ -1008,7 +1008,8 @@ loongarch_save_restore_reg (machine_mode mode, int regno, HOST_WIDE_INT offset, static void loongarch_for_each_saved_reg (HOST_WIDE_INT sp_offset, - loongarch_save_restore_fn fn) + loongarch_save_restore_fn fn, + bool skip_eh_data_regs_p) { HOST_WIDE_INT offset; @@ -1017,7 +1018,15 @@ loongarch_for_each_saved_reg (HOST_WIDE_INT sp_offset, for (int regno = GP_REG_FIRST; regno <= GP_REG_LAST; regno++) if (BITSET_P (cfun->machine->frame.mask, regno - GP_REG_FIRST)) { - loongarch_save_restore_reg (word_mode, regno, offset, fn); + /* Special care needs to be taken for $r4-$r7 (EH_RETURN_DATA_REGNO) + when returning normally from a function that calls + __builtin_eh_return. In this case, these registers are saved but + should not be restored, or the return value may be clobbered. */ + + if (!(skip_eh_data_regs_p + && GP_ARG_FIRST <= regno && regno < GP_ARG_FIRST + 4)) + loongarch_save_restore_reg (word_mode, regno, offset, fn); + offset -= UNITS_PER_WORD; } @@ -1289,7 +1298,7 @@ loongarch_expand_prologue (void) GEN_INT (-step1)); RTX_FRAME_RELATED_P (emit_insn (insn)) = 1; size -= step1; - loongarch_for_each_saved_reg (size, loongarch_save_reg); + loongarch_for_each_saved_reg (size, loongarch_save_reg, false); } @@ -1336,11 +1345,13 @@ loongarch_can_use_return_insn (void) return reload_completed && cfun->machine->frame.total_size == 0; } -/* Expand an "epilogue" or "sibcall_epilogue" pattern; SIBCALL_P - says which. */ +/* Expand function epilogue using the following insn patterns: + "epilogue" (style == NORMAL_RETURN) + "sibcall_epilogue" (style == SIBCALL_RETURN) + "eh_return" (style == EXCEPTION_RETURN) */ void -loongarch_expand_epilogue (bool sibcall_p) +loongarch_expand_epilogue (int style) { /* Split the frame into two. STEP1 is the amount of stack we should deallocate before restoring the registers. STEP2 is the amount we @@ -1357,7 +1368,8 @@ loongarch_expand_epilogue (bool sibcall_p) bool need_barrier_p = (get_frame_size () + cfun->machine->frame.arg_pointer_offset) != 0; - if (!sibcall_p && loongarch_can_use_return_insn ()) + /* Handle simple returns. */ + if (style == NORMAL_RETURN && loongarch_can_use_return_insn ()) { emit_jump_insn (gen_return ()); return; @@ -1433,7 +1445,9 @@ loongarch_expand_epilogue (bool sibcall_p) /* Restore the registers. */ loongarch_for_each_saved_reg (frame->total_size - step2, - loongarch_restore_reg); + loongarch_restore_reg, + crtl->calls_eh_return + && style != EXCEPTION_RETURN); if (need_barrier_p) loongarch_emit_stack_tie (); @@ -1454,11 +1468,12 @@ loongarch_expand_epilogue (bool sibcall_p) } /* Add in the __builtin_eh_return stack adjustment. */ - if (crtl->calls_eh_return) + if (crtl->calls_eh_return && style == EXCEPTION_RETURN) emit_insn (gen_add3_insn (stack_pointer_rtx, stack_pointer_rtx, EH_RETURN_STACKADJ_RTX)); - if (!sibcall_p) + /* Emit return unless doing sibcall. */ + if (style != SIBCALL_RETURN) emit_jump_insn (gen_simple_return_internal (ra)); } diff --git a/gcc/config/loongarch/loongarch.md b/gcc/config/loongarch/loongarch.md index b49e058407c..1361e7ba7bf 100644 --- a/gcc/config/loongarch/loongarch.md +++ b/gcc/config/loongarch/loongarch.md @@ -98,6 +98,11 @@ (define_constants (T1_REGNUM 13) (S0_REGNUM 23) + ;; Return path styles + (NORMAL_RETURN 0) + (SIBCALL_RETURN 1) + (EXCEPTION_RETURN 2) + ;; PIC long branch sequences are never longer than 100 bytes. (MAX_PIC_BRANCH_LENGTH 100) ]) @@ -2715,7 +2720,7 @@ (define_expand "epilogue" [(const_int 2)] "" { - loongarch_expand_epilogue (false); + loongarch_expand_epilogue (NORMAL_RETURN); DONE; }) @@ -2723,7 +2728,7 @@ (define_expand "sibcall_epilogue" [(const_int 2)] "" { - loongarch_expand_epilogue (true); + loongarch_expand_epilogue (SIBCALL_RETURN); DONE; }) @@ -2780,6 +2785,20 @@ (define_expand "eh_return" emit_insn (gen_eh_set_ra_di (operands[0])); else emit_insn (gen_eh_set_ra_si (operands[0])); + + emit_jump_insn (gen_eh_return_internal ()); + emit_barrier (); + DONE; +}) + +(define_insn_and_split "eh_return_internal" + [(eh_return)] + "" + "#" + "epilogue_completed" + [(const_int 0)] +{ + loongarch_expand_epilogue (EXCEPTION_RETURN); DONE; }) diff --git a/gcc/testsuite/gcc.target/loongarch/eh_return-normal-return.c b/gcc/testsuite/gcc.target/loongarch/eh_return-normal-return.c new file mode 100644 index 00000000000..f8f3965f894 --- /dev/null +++ b/gcc/testsuite/gcc.target/loongarch/eh_return-normal-return.c @@ -0,0 +1,38 @@ +/* { dg-do run } */ +/* { dg-options "-O2" } */ + +#include + +int foo () __attribute__((noinline)); +int main (); + +int +foo () { + + int t; + + /* prevent optimization using asm */ + asm ("" : "=r" (t) : "0" (-1)); + asm ("" : "=r" (t) : "0" (t ? 1 : 0)); + + if (t == 0) + /* never reached */ + __builtin_eh_return (0, __builtin_return_address (0)); + + else if (t == 1) + /* return here */ + return 202312; + + else + /* never reached: prevent vrp optimization in main */ + return 0; +} + +int +main () +{ + if (foo() == 202312) + return 0; + else + abort (); +}