On 02/01/2018 01:26 PM, Stefan Hajnoczi wrote: > SystemTap's dtrace(1) produces the following warning when it encounters > "char const" instead of "const char": > > Warning: /usr/bin/dtrace:trace-dtrace-root.dtrace:66: syntax error near: > probe flatview_destroy_rcu > > Warning: Proceeding as if --no-pyparsing was given. > > This is a limitation in current SystemTap releases. I have sent a patch > upstream to accept "char const" since it is valid C: > > https://sourceware.org/ml/systemtap/2018-q1/msg00017.html
Valid but bad practice :) It is easier to confuse: char const* a; char *const a; while this is clearer: const char* a; char *const a; also: cdecl> explain const char* a declare a as pointer to const char cdecl> explain char *const a declare a as const pointer to char but: cdecl> explain char const* a syntax error and while here, cdecl> explain const char *const a declare a as const pointer to const char :) Personally I'd like checkpatch not accepting this confuse syntax. > > In QEMU we still wish to avoid warnings in the current SystemTap > release. It's simple enough to replace "char const" with "const char". > > I'm not changing the documentation or implementing checks to prevent > this from occurring again in the future. The next release of SystemTap > will hopefully resolve this issue. > > Cc: Daniel P. Berrange <berra...@redhat.com> > Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4...@amsat.org> > --- > hw/block/trace-events | 4 ++-- > trace-events | 12 ++++++------ > 2 files changed, 8 insertions(+), 8 deletions(-) > > diff --git a/hw/block/trace-events b/hw/block/trace-events > index 5acd495207..6b9e733412 100644 > --- a/hw/block/trace-events > +++ b/hw/block/trace-events > @@ -17,7 +17,7 @@ nvme_irq_msix(uint32_t vector) "raising MSI-X IRQ vector %u" > nvme_irq_pin(void) "pulsing IRQ pin" > nvme_irq_masked(void) "IRQ is masked" > nvme_dma_read(uint64_t prp1, uint64_t prp2) "DMA read, prp1=0x%"PRIx64" > prp2=0x%"PRIx64"" > -nvme_rw(char const *verb, uint32_t blk_count, uint64_t byte_count, uint64_t > lba) "%s %"PRIu32" blocks (%"PRIu64" bytes) from LBA %"PRIu64"" > +nvme_rw(const char *verb, uint32_t blk_count, uint64_t byte_count, uint64_t > lba) "%s %"PRIu32" blocks (%"PRIu64" bytes) from LBA %"PRIu64"" > nvme_create_sq(uint64_t addr, uint16_t sqid, uint16_t cqid, uint16_t qsize, > uint16_t qflags) "create submission queue, addr=0x%"PRIx64", sqid=%"PRIu16", > cqid=%"PRIu16", qsize=%"PRIu16", qflags=%"PRIu16"" > nvme_create_cq(uint64_t addr, uint16_t cqid, uint16_t vector, uint16_t size, > uint16_t qflags, int ien) "create completion queue, addr=0x%"PRIx64", > cqid=%"PRIu16", vector=%"PRIu16", qsize=%"PRIu16", qflags=%"PRIu16", ien=%d" > nvme_del_sq(uint16_t qid) "deleting submission queue sqid=%"PRIu16"" > @@ -25,7 +25,7 @@ nvme_del_cq(uint16_t cqid) "deleted completion queue, > sqid=%"PRIu16"" > nvme_identify_ctrl(void) "identify controller" > nvme_identify_ns(uint16_t ns) "identify namespace, nsid=%"PRIu16"" > nvme_identify_nslist(uint16_t ns) "identify namespace list, nsid=%"PRIu16"" > -nvme_getfeat_vwcache(char const* result) "get feature volatile write cache, > result=%s" > +nvme_getfeat_vwcache(const char* result) "get feature volatile write cache, > result=%s" > nvme_getfeat_numq(int result) "get feature number of queues, result=%d" > nvme_setfeat_numq(int reqcq, int reqsq, int gotcq, int gotsq) "requested > cq_count=%d sq_count=%d, responding with cq_count=%d sq_count=%d" > nvme_mmio_intm_set(uint64_t data, uint64_t new_mask) "wrote MMIO, interrupt > mask set, data=0x%"PRIx64", new_mask=0x%"PRIx64"" > diff --git a/trace-events b/trace-events > index ec95e67089..89fcad0fd1 100644 > --- a/trace-events > +++ b/trace-events > @@ -73,13 +73,13 @@ flatview_destroy(FlatView *view, MemoryRegion *root) "%p > (root %p)" > flatview_destroy_rcu(FlatView *view, MemoryRegion *root) "%p (root %p)" > > # gdbstub.c > -gdbstub_op_start(char const *device) "Starting gdbstub using device %s" > +gdbstub_op_start(const char *device) "Starting gdbstub using device %s" > gdbstub_op_exiting(uint8_t code) "notifying exit with code=0x%02x" > gdbstub_op_continue(void) "Continuing all CPUs" > gdbstub_op_continue_cpu(int cpu_index) "Continuing CPU %d" > gdbstub_op_stepping(int cpu_index) "Stepping CPU %d" > -gdbstub_op_extra_info(char const *info) "Thread extra info: %s" > -gdbstub_hit_watchpoint(char const *type, int cpu_gdb_index, uint64_t vaddr) > "Watchpoint hit, type=\"%s\" cpu=%d, vaddr=0x%" PRIx64 "" > +gdbstub_op_extra_info(const char *info) "Thread extra info: %s" > +gdbstub_hit_watchpoint(const char *type, int cpu_gdb_index, uint64_t vaddr) > "Watchpoint hit, type=\"%s\" cpu=%d, vaddr=0x%" PRIx64 "" > gdbstub_hit_internal_error(void) "RUN_STATE_INTERNAL_ERROR" > gdbstub_hit_break(void) "RUN_STATE_DEBUG" > gdbstub_hit_paused(void) "RUN_STATE_PAUSED" > @@ -87,9 +87,9 @@ gdbstub_hit_shutdown(void) "RUN_STATE_SHUTDOWN" > gdbstub_hit_io_error(void) "RUN_STATE_IO_ERROR" > gdbstub_hit_watchdog(void) "RUN_STATE_WATCHDOG" > gdbstub_hit_unknown(int state) "Unknown run state=0x%x" > -gdbstub_io_reply(char const *message) "Sent: %s" > -gdbstub_io_binaryreply(size_t ofs, char const *line) "0x%04zx: %s" > -gdbstub_io_command(char const *command) "Received: %s" > +gdbstub_io_reply(const char *message) "Sent: %s" > +gdbstub_io_binaryreply(size_t ofs, const char *line) "0x%04zx: %s" > +gdbstub_io_command(const char *command) "Received: %s" > gdbstub_io_got_ack(void) "Got ACK" > gdbstub_io_got_unexpected(uint8_t ch) "Got 0x%02x when expecting ACK/NACK" > gdbstub_err_got_nack(void) "Got NACK, retransmitting" >
