From 9b409511d07fe375284701af34909fb539029caf Mon Sep 17 00:00:00 2001 From: Yao Qi Date: Mon, 27 Jan 2014 20:35:33 +0800 Subject: Return target_xfer_status in to_xfer_partial This patch does the conversion of to_xfer_partial from LONGEST (*to_xfer_partial) (struct target_ops *ops, enum target_object object, const char *annex, gdb_byte *readbuf, const gdb_byte *writebuf, ULONGEST offset, ULONGEST len); to enum target_xfer_status (*to_xfer_partial) (struct target_ops *ops, enum target_object object, const char *annex, gdb_byte *readbuf, const gdb_byte *writebuf, ULONGEST offset, ULONGEST len, ULONGEST *xfered_len); It changes to_xfer_partial return the transfer status and the transfered length by *XFERED_LEN. Generally, the return status has three stats, - TARGET_XFER_OK, - TARGET_XFER_EOF, - TARGET_XFER_E_XXXX, See the comments to them in 'enum target_xfer_status'. Note that Pedro suggested not name TARGET_XFER_DONE, as it is confusing, compared with "TARGET_XFER_OK". We finally name it TARGET_XFER_EOF. With this change, GDB core can handle unavailable data in a convenient way. The rationale behind this change was mentioned here https://sourceware.org/ml/gdb-patches/2013-10/msg00761.html Consider an object/value like this: 0 100 150 200 512 DDDDDDDDDDDxxxxxxxxxDDDDDD...DDIIIIIIIIIIII..III where D is valid data, and xxx is unavailable data, and I is beyond the end of the object (Invalid). Currently, if we start the xfer at 0, requesting, say 512 bytes, we'll first get back 100 bytes. The xfer machinery then retries fetching [100,512), and gets back TARGET_XFER_E_UNAVAILABLE. That's sufficient when you're either interested in either having the whole of the 512 bytes available, or erroring out. But, in this scenario, we're interested in the data at [150,512). The problem is that the last TARGET_XFER_E_UNAVAILABLE gives us no indication where to start the read next. We'd need something like: get me [0,512) >>> <<< here's [0,100), *xfered_len is 100, returns TARGET_XFER_OK get me [100,512) >>> (**1) <<< [100,150) is unavailable, *xfered_len is 50, return TARGET_XFER_E_UNAVAILABLE. get me [150,512) >>> <<< here's [150,200), *xfered_len is 50, return TARGET_XFER_OK. get me [200,512) >>> <<< no more data, return TARGET_XFER_EOF. This naturally implies pushing down the decision of whether to return TARGET_XFER_E_UNAVAILABLE or something else down to the target. (Which kinds of leads back to tfile itself reading from RO memory from file (though we could export a function in exec.c for that that tfile delegates to, instead of re-adding the old code). Beside this change, we also add a macro TARGET_XFER_STATUS_ERROR_P to check whether a status is an error or not, to stop using "status < 0". This patch also eliminates the comparison between status and 0. No target implementations to to_xfer_partial adapts this new interface. The interface still behaves as before. gdb: 2014-02-11 Yao Qi * target.h (enum target_xfer_error): Rename to ... (enum target_xfer_status): ... it. New. All users updated. (enum target_xfer_status) , : New. (TARGET_XFER_STATUS_ERROR_P): New macro. (target_xfer_error_to_string): Remove declaration. (target_xfer_status_to_string): Declare. (target_xfer_partial_ftype): Adjust it. (struct target_ops) : Return target_xfer_status. Add argument xfered_len. Update comments. * target.c (target_xfer_error_to_string): Rename to ... (target_xfer_status_to_string): ... it. New. All callers updated. (target_read_live_memory): Likewise. Call target_xfer_partial instead of target_read. (memory_xfer_live_readonly_partial): Return target_xfer_status. Add argument xfered_len. (raw_memory_xfer_partial): Likewise. (memory_xfer_partial_1): Likewise. (memory_xfer_partial): Likewise. (target_xfer_partial): Likewise. Check *XFERED_LEN is set properly. Update debug message. (default_xfer_partial, current_xfer_partial): Likewise. (target_write_partial): Likewise. (target_read_partial): Likewise. All callers updated. (read_whatever_is_readable): Likewise. (target_write_with_progress): Likewise. (target_read_alloc_1): Likewise. * aix-thread.c (aix_thread_xfer_partial): Likewise. * auxv.c (procfs_xfer_auxv): Likewise. (ld_so_xfer_auxv, memory_xfer_auxv): Likewise. * bfd-target.c (target_bfd_xfer_partial): Likewise. * bsd-kvm.c (bsd_kvm_xfer_partial): Likewise. * bsd-uthread.c (bsd_uthread_xfer_partia): Likewise. * corefile.c (read_memory): Adjust. * corelow.c (core_xfer_partial): Likewise. * ctf.c (ctf_xfer_partial): Likewise. * darwin-nat.c (darwin_read_dyld_info): Likewise. All callers updated. (darwin_xfer_partial): Likewise. * exec.c (section_table_xfer_memory_partial): Likewise. All callers updated. (exec_xfer_partial): Likewise. * exec.h (section_table_xfer_memory_partial): Update declaration. * gnu-nat.c (gnu_xfer_memory): Likewise. Assert 'res' is not negative. (gnu_xfer_partial): Likewise. * ia64-hpux-nat.c (ia64_hpux_xfer_memory_no_bs): Likewise. (ia64_hpux_xfer_memory, ia64_hpux_xfer_uregs): Likewise. (ia64_hpux_xfer_solib_got): Likewise. * inf-ptrace.c (inf_ptrace_xfer_partial): Likewise. Change type of 'partial_len' to ULONGEST. * inf-ttrace.c (inf_ttrace_xfer_partial): Likewise. * linux-nat.c (linux_xfer_siginfo ): Likewise. (linux_nat_xfer_partial): Likewise. (linux_proc_xfer_partial, linux_xfer_partial): Likewise. (linux_proc_xfer_spu, linux_nat_xfer_osdata): Likewise. * monitor.c (monitor_xfer_memory): Likewise. (monitor_xfer_partial): Likewise. * procfs.c (procfs_xfer_partial): Likewise. * record-btrace.c (record_btrace_xfer_partial): Likewise. * record-full.c (record_full_xfer_partial): Likewise. (record_full_core_xfer_partial): Likewise. * remote-sim.c (gdbsim_xfer_memory): Likewise. (gdbsim_xfer_partial): Likewise. * remote.c (remote_write_bytes_aux): Likewise. All callers updated. (remote_write_bytes, remote_read_bytes): Likewise. All callers updated. (remote_flash_erase): Likewise. All callers updated. (remote_write_qxfer): Likewise. All callers updated. (remote_read_qxfer): Likewise. All callers updated. (remote_xfer_partial): Likewise. * rs6000-nat.c (rs6000_xfer_partial): Likewise. (rs6000_xfer_shared_libraries): Likewise. * sol-thread.c (sol_thread_xfer_partial): Likewise. (sol_thread_xfer_partial): Likewise. * sparc-nat.c (sparc_xfer_wcookie): Likewise. (sparc_xfer_partial): Likewise. * spu-linux-nat.c (spu_proc_xfer_spu): Likewise. All callers updated. (spu_xfer_partial): Likewise. * spu-multiarch.c (spu_xfer_partial): Likewise. * tracepoint.c (tfile_xfer_partial): Likewise. * windows-nat.c (windows_xfer_memory): Likewise. (windows_xfer_shared_libraries): Likewise. (windows_xfer_partial): Likewise. * valprint.c: Replace 'target_xfer_error' with 'target_xfer_status' in comments. --- gdb/remote-sim.c | 24 +++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) (limited to 'gdb/remote-sim.c') diff --git a/gdb/remote-sim.c b/gdb/remote-sim.c index 0322c1d..163af41 100644 --- a/gdb/remote-sim.c +++ b/gdb/remote-sim.c @@ -1061,10 +1061,10 @@ gdbsim_prepare_to_store (struct target_ops *self, struct regcache *regcache) /* Helper for gdbsim_xfer_partial that handles memory transfers. Arguments are like target_xfer_partial. */ -static LONGEST +static enum target_xfer_status gdbsim_xfer_memory (struct target_ops *target, gdb_byte *readbuf, const gdb_byte *writebuf, - ULONGEST memaddr, ULONGEST len) + ULONGEST memaddr, ULONGEST len, ULONGEST *xfered_len) { struct sim_inferior_data *sim_data = get_sim_inferior_data (current_inferior (), SIM_INSTANCE_NOT_NEEDED); @@ -1074,7 +1074,7 @@ gdbsim_xfer_memory (struct target_ops *target, request to be passed to a lower target, hopefully an exec file. */ if (!target->to_has_memory (target)) - return 0; + return TARGET_XFER_EOF; if (!sim_data->program_loaded) error (_("No program loaded.")); @@ -1108,20 +1108,30 @@ gdbsim_xfer_memory (struct target_ops *target, if (remote_debug && len > 0) dump_mem (readbuf, len); } - return l; + if (l > 0) + { + *xfered_len = (ULONGEST) l; + return TARGET_XFER_OK; + } + else if (l == 0) + return TARGET_XFER_EOF; + else + return TARGET_XFER_E_IO; } /* Target to_xfer_partial implementation. */ -static LONGEST +static enum target_xfer_status gdbsim_xfer_partial (struct target_ops *ops, enum target_object object, const char *annex, gdb_byte *readbuf, - const gdb_byte *writebuf, ULONGEST offset, ULONGEST len) + const gdb_byte *writebuf, ULONGEST offset, ULONGEST len, + ULONGEST *xfered_len) { switch (object) { case TARGET_OBJECT_MEMORY: - return gdbsim_xfer_memory (ops, readbuf, writebuf, offset, len); + return gdbsim_xfer_memory (ops, readbuf, writebuf, offset, len, + xfered_len); default: return TARGET_XFER_E_IO; -- cgit v1.1