From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca by simark.ca with LMTP id Tj0lNb64RmDVcgAAWB0awg (envelope-from ) for ; Mon, 08 Mar 2021 18:52:30 -0500 Received: by simark.ca (Postfix, from userid 112) id C9D821EF78; Mon, 8 Mar 2021 18:52:30 -0500 (EST) X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on simark.ca X-Spam-Level: X-Spam-Status: No, score=-1.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.2 Received: from sourceware.org (server2.sourceware.org [8.43.85.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by simark.ca (Postfix) with ESMTPS id BD7BB1E793 for ; Mon, 8 Mar 2021 18:52:29 -0500 (EST) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 0D2073861823; Mon, 8 Mar 2021 23:52:29 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 0D2073861823 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1615247549; bh=Z5COnxx4ymGxI6ff/GsdtNAREjEShJTVPXxwB2TZsU8=; h=Date:To:Subject:References:In-Reply-To:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=Pcc4MM3OznhJRQl/GTC2J3EixO4KmU3SWg3IxBxIG+cJvYrk7vgkAgoEgtA8ofPer gzU6tYerTvSpiL+7Xch4sYcDiMt/TXserYzM7UTPvGOGY8sl8EHUizadifH/yelX3X RWAVvKdVa2mtYtvtxAcY287/kEemL48D9I+hihzE= Received: from beryx.lancelotsix.com (beryx.lancelotsix.com [164.132.98.193]) by sourceware.org (Postfix) with ESMTPS id 9A62B3861027 for ; Mon, 8 Mar 2021 23:52:22 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 9A62B3861027 Received: from Plymouth (unknown [IPv6:2a02:390:8443:0:a108:6ed3:481d:d9e1]) by beryx.lancelotsix.com (Postfix) with ESMTPSA id C97D02E03B; Tue, 9 Mar 2021 00:52:20 +0100 (CET) Date: Mon, 8 Mar 2021 23:52:19 +0000 To: Zoran Zaric Subject: Re: [PATCH 18/43] Add new register access interface to expr.c Message-ID: References: <20210301144620.103016-1-Zoran.Zaric@amd.com> <20210301144620.103016-19-Zoran.Zaric@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20210301144620.103016-19-Zoran.Zaric@amd.com> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.11 (beryx.lancelotsix.com [0.0.0.0]); Tue, 09 Mar 2021 00:52:21 +0100 (CET) X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Lancelot SIX via Gdb-patches Reply-To: Lancelot SIX Cc: gdb-patches@sourceware.org Errors-To: gdb-patches-bounces@sourceware.org Sender: "Gdb-patches" Hi, I have minor style related comments above. Le Mon, Mar 01, 2021 at 02:45:55PM +0000, Zoran Zaric via Gdb-patches a écrit : > DWARF expression evaluator is currently using get_frame_register_bytes > and put_frame_register_bytes interface for register access. > > The problem with evaluator using this interface is that it allows a > bleed out register access. This means that if the caller specifies a > larger amount of data then the size of a specified register, the > operation will continue accessing the neighboring registers until a > full amount of data has been reached. > > DWARF specification does not define this behavior, so a new simplified > register access interface is needed instead. > > * dwarf2/expr.c (read_from_register): New function. > (write_to_register): New function. > (rw_pieced_value): Now calls the read_from_register and > write_to_register functions. > --- > gdb/dwarf2/expr.c | 128 ++++++++++++++++++++++++++++++++++++++-------- > 1 file changed, 106 insertions(+), 22 deletions(-) > > diff --git a/gdb/dwarf2/expr.c b/gdb/dwarf2/expr.c > index c50bb3c8d90..5a1fd5b941f 100644 > --- a/gdb/dwarf2/expr.c > +++ b/gdb/dwarf2/expr.c > @@ -106,6 +106,96 @@ read_addr_from_reg (struct frame_info *frame, int reg) > return address_from_register (regnum, frame); > } > > +/* Read register REGNUM's contents in a given FRAME context. > + > + The data read is offsetted by OFFSET, and the number of bytes read > + is defined by LENGTH. The data is then copied into the > + caller-managed buffer BUF. > + > + If the register is optimized out or unavailable for the given > + FRAME, the OPTIMIZED and UNAVAILABLE outputs are set > + accordingly */ > + > +static void > +read_from_register (struct frame_info *frame, int regnum, > + CORE_ADDR offset, gdb::array_view buf, > + int *optimized, int *unavailable) > +{ > + struct gdbarch *gdbarch = get_frame_arch (frame); > + int regsize = register_size (gdbarch, regnum); > + int numregs = gdbarch_num_cooked_regs (gdbarch); > + int length = buf.size (); > + > + /* If a register is wholly inside the OFFSET, skip it. */ > + if (frame == NULL || !regsize Gdb coding standard asks for explicit comparison of numbers (https://sourceware.org/gdb/wiki/Internals%20GDB-C-Coding-Standards#Comparison_With_NULL_And_Zero). !regsize should be regsize == 0. I guess NULL could also be changed to nullptr. > + || offset + length > regsize || numregs < regnum) > + { > + *optimized = 0; > + *unavailable = 1; > + return; > + } > + > + gdb::byte_vector temp_buf (regsize); > + enum lval_type lval; > + CORE_ADDR address; > + int realnum; > + > + frame_register (frame, regnum, optimized, unavailable, > + &lval, &address, &realnum, temp_buf.data ()); > + > + if (!*optimized && !*unavailable) > + memcpy (buf.data (), (char *) temp_buf.data () + offset, length); > + > + return; I changes nothing, but I find it odd to have a return; as last statement of a void returning function. > +} > + > +/* Write register REGNUM's contents in a given FRAME context. > + > + The data written is offsetted by OFFSET, and the number of bytes > + written is defined by LENGTH. The data is copied from > + caller-managed buffer BUF. > + > + If the register is optimized out or unavailable for the given > + FRAME, the OPTIMIZED and UNAVAILABLE outputs are set > + accordingly. */ > + > +static void > +write_to_register (struct frame_info *frame, int regnum, > + CORE_ADDR offset, gdb::array_view buf, > + int *optimized, int *unavailable) > +{ > + struct gdbarch *gdbarch = get_frame_arch (frame); > + int regsize = register_size (gdbarch, regnum); > + int numregs = gdbarch_num_cooked_regs (gdbarch); > + int length = buf.size (); > + > + /* If a register is wholly inside of OFFSET, skip it. */ > + if (frame == NULL || !regsize Same remark for regsize. Thanks, Lancelot. > + || offset + length > regsize || numregs < regnum) > + { > + *optimized = 0; > + *unavailable = 1; > + return; > + } > + > + gdb::byte_vector temp_buf (regsize); > + enum lval_type lval; > + CORE_ADDR address; > + int realnum; > + > + frame_register (frame, regnum, optimized, unavailable, > + &lval, &address, &realnum, temp_buf.data ()); > + > + if (!*optimized && !*unavailable) > + { > + memcpy ((chr *) temp_buf.data () + offset, buf.data (), length); > + > + put_frame_register (frame, regnum, temp_buf.data ()); > + } > + > + return; > +} > + > struct piece_closure > { > /* Reference count. */ > @@ -243,22 +333,18 @@ rw_pieced_value (struct value *v, struct value *from) > if (from == NULL) > { > /* Read mode. */ > - if (!get_frame_register_bytes (frame, gdb_regnum, > - bits_to_skip / 8, > - buffer, &optim, &unavail)) > - { > - if (optim) > - mark_value_bits_optimized_out (v, offset, > - this_size_bits); > - if (unavail) > - mark_value_bits_unavailable (v, offset, > - this_size_bits); > - break; > - } > - > - copy_bitwise (v_contents, offset, > - buffer.data (), bits_to_skip % 8, > - this_size_bits, bits_big_endian); > + read_from_register (frame, gdb_regnum, bits_to_skip / 8, > + buffer, &optim, &unavail); > + > + if (optim) > + mark_value_bits_optimized_out (v, offset, this_size_bits); > + if (unavail) > + mark_value_bits_unavailable (v, offset, this_size_bits); > + /* Only copy data if valid. */ > + if (!optim && !unavail) > + copy_bitwise (v_contents, offset, > + buffer.data (), bits_to_skip % 8, > + this_size_bits, bits_big_endian); > } > else > { > @@ -267,9 +353,8 @@ rw_pieced_value (struct value *v, struct value *from) > { > /* Data is copied non-byte-aligned into the register. > Need some bits from original register value. */ > - get_frame_register_bytes (frame, gdb_regnum, > - bits_to_skip / 8, > - buffer, &optim, &unavail); > + read_from_register (frame, gdb_regnum, bits_to_skip / 8, > + buffer, &optim, &unavail); > if (optim) > throw_error (OPTIMIZED_OUT_ERROR, > _("Can't do read-modify-write to " > @@ -285,9 +370,8 @@ rw_pieced_value (struct value *v, struct value *from) > copy_bitwise (buffer.data (), bits_to_skip % 8, > from_contents, offset, > this_size_bits, bits_big_endian); > - put_frame_register_bytes (frame, gdb_regnum, > - bits_to_skip / 8, > - buffer); > + write_to_register (frame, gdb_regnum, bits_to_skip / 8, > + buffer, &optim, &unavail); > } > } > break; > -- > 2.17.1 > -- Lancelot SIX