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[87.115.72.95]) by smtp.gmail.com with ESMTPSA id v14-20020adfedce000000b002c7b229b1basm8091017wro.15.2023.02.27.13.29.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 27 Feb 2023 13:29:43 -0800 (PST) To: gdb-patches@sourceware.org Cc: Andrew Burgess Subject: [PATCH 10/13] gdb: remove some uses of alloca from printcmd.c Date: Mon, 27 Feb 2023 21:29:23 +0000 Message-Id: <6329d414746b1b6fe6d5c32d9ab5c183b5719719.1677533215.git.aburgess@redhat.com> X-Mailer: git-send-email 2.25.4 In-Reply-To: References: MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-Spam-Status: No, score=-11.7 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_NONE, 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: 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: , X-Patchwork-Original-From: Andrew Burgess via Gdb-patches From: Andrew Burgess Reply-To: Andrew Burgess Errors-To: gdb-patches-bounces+patchwork=sourceware.org@sourceware.org Sender: "Gdb-patches" Remove a couple of uses of alloca from printcmd.c, and replace them with gdb::byte_vector. Unlike most times when alloca is replace with gdb::byte_vector, the size of the vector is not specified at the byte_vector creation time. In this case the vector can be sized differently depending on which path of an `if` is taken, however, the lifetime of the data within the vector must extend beyond the `if` itself. There is a remaining use of alloca in this file, but that case will not be replace with gdb::byte_vector, so I've left that for now. There should be no user visible changes after this commit. --- gdb/printcmd.c | 44 +++++++++++++++++++++----------------------- 1 file changed, 21 insertions(+), 23 deletions(-) diff --git a/gdb/printcmd.c b/gdb/printcmd.c index 0d3bc292d4e..1efd3cabf54 100644 --- a/gdb/printcmd.c +++ b/gdb/printcmd.c @@ -2443,7 +2443,7 @@ static void printf_c_string (struct ui_file *stream, const char *format, struct value *value) { - const gdb_byte *str; + gdb::byte_vector str; if (value->type ()->code () != TYPE_CODE_PTR && value->lval () == lval_internalvar @@ -2455,11 +2455,10 @@ printf_c_string (struct ui_file *stream, const char *format, character. This protects against corrupted C-style strings that lack the terminating null char. It also allows Ada-style strings (not null terminated) to be printed without problems. */ - gdb_byte *tem_str = (gdb_byte *) alloca (len + 1); + str.resize (len + 1); - memcpy (tem_str, value->contents ().data (), len); - tem_str [len] = 0; - str = tem_str; + memcpy (str.data (), value->contents ().data (), len); + str [len] = 0; } else { @@ -2474,31 +2473,30 @@ printf_c_string (struct ui_file *stream, const char *format, return; } - /* This is a %s argument. Find the length of the string. */ - size_t len; - - for (len = 0;; len++) + /* This is a %s argument. Build the string in STR which is + currently empty. */ + gdb_assert (str.size () == 0); + for (size_t len = 0;; len++) { gdb_byte c; QUIT; read_memory (tem + len, &c, 1); + str.push_back (c); if (c == 0) break; } - /* Copy the string contents into a string inside GDB. */ - gdb_byte *tem_str = (gdb_byte *) alloca (len + 1); - - if (len != 0) - read_memory (tem, tem_str, len); - tem_str[len] = 0; - str = tem_str; + /* We will have passed through the above loop at least once, and will + only exit the loop when we have pushed a zero byte onto the end of + STR. */ + gdb_assert (str.size () > 0); + gdb_assert (str.back () == 0); } DIAGNOSTIC_PUSH DIAGNOSTIC_IGNORE_FORMAT_NONLITERAL - gdb_printf (stream, format, (char *) str); + gdb_printf (stream, format, (char *) str.data ()); DIAGNOSTIC_POP } @@ -2539,23 +2537,23 @@ printf_wide_c_string (struct ui_file *stream, const char *format, /* This is a %s argument. Find the length of the string. */ enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); - gdb_byte *buf = (gdb_byte *) alloca (wcwidth); + gdb::byte_vector buf (wcwidth); for (len = 0;; len += wcwidth) { QUIT; - read_memory (tem + len, buf, wcwidth); - if (extract_unsigned_integer (buf, wcwidth, byte_order) == 0) + read_memory (tem + len, buf.data (), wcwidth); + if (extract_unsigned_integer (buf.data (), wcwidth, byte_order) == 0) break; } /* Copy the string contents into a string inside GDB. */ - gdb_byte *tem_str = (gdb_byte *) alloca (len + wcwidth); + gdb::byte_vector tem_str (len + wcwidth); if (len != 0) - read_memory (tem, tem_str, len); + read_memory (tem, tem_str.data (), len); memset (&tem_str[len], 0, wcwidth); - str = tem_str; + str = tem_str.data (); } auto_obstack output;