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Re: [PATCH 3/5] gdbstub: Use fixed-size array in GdbCmdParseEntry instea
From: |
Alex Bennée |
Subject: |
Re: [PATCH 3/5] gdbstub: Use fixed-size array in GdbCmdParseEntry instead of pointer |
Date: |
Thu, 06 May 2021 13:01:57 +0100 |
User-agent: |
mu4e 1.5.13; emacs 28.0.50 |
Philippe Mathieu-Daudé <philmd@redhat.com> writes:
> GdbCmdParseEntry should have enough room with 20 chars for the command
> string, and 8 for the schema. Add the GDB_CMD_PARSE_ENTRY_CMD_SIZE and
> GDB_CMD_PARSE_ENTRY_SCHEMA_SIZE definitions.
>
> Do not use pointer to string of unknown length, but array of fixed
> size. Having constant size will help use to remove the alloca() call
> in process_string_cmd() in the next commit.
I don't understand how this helps. The alloca is being used for an array
of GdbCmdVariant so why do we want to enlarge the size of the parse
table entries?
>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
> gdbstub.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/gdbstub.c b/gdbstub.c
> index 6f663cbd8dd..0d5569ee539 100644
> --- a/gdbstub.c
> +++ b/gdbstub.c
> @@ -1457,11 +1457,13 @@ typedef void (*GdbCmdHandler)(GdbCmdContext *gdb_ctx,
> void *user_ctx);
> * '.' -> Skip 1 char unless reached "\0"
> * Any other value is treated as the delimiter value itself
> */
> +#define GDB_CMD_PARSE_ENTRY_CMD_SIZE 20
> +#define GDB_CMD_PARSE_ENTRY_SCHEMA_SIZE 8
> typedef struct GdbCmdParseEntry {
> GdbCmdHandler handler;
> - const char *cmd;
> + const char cmd[GDB_CMD_PARSE_ENTRY_CMD_SIZE];
> bool cmd_startswith;
> - const char *schema;
> + const char schema[GDB_CMD_PARSE_ENTRY_SCHEMA_SIZE];
> } GdbCmdParseEntry;
>
> static inline int startswith(const char *string, const char *pattern)
> @@ -1481,14 +1483,14 @@ static int process_string_cmd(void *user_ctx, const
> char *data,
>
> for (i = 0; i < num_cmds; i++) {
> const GdbCmdParseEntry *cmd = &cmds[i];
> - g_assert(cmd->handler && cmd->cmd);
> + g_assert(cmd->handler && *cmd->cmd);
>
> if ((cmd->cmd_startswith && !startswith(data, cmd->cmd)) ||
> (!cmd->cmd_startswith && strcmp(cmd->cmd, data))) {
> continue;
> }
>
> - if (cmd->schema) {
> + if (*cmd->schema) {
> schema_len = strlen(cmd->schema);
> if (schema_len % 2) {
> return -2;
--
Alex Bennée