[PATCH 1/3] gdb/jit: use a map to store objfile and jit breakpoint info
Simon Marchi
simark@simark.ca
Sun Jun 14 17:50:23 GMT 2020
On 2020-05-25 5:38 a.m., Tankut Baris Aktemur via Gdb-patches wrote:
> diff --git a/gdb/jit.c b/gdb/jit.c
> index 1b5ef46469e..fdb1248ed5b 100644
> --- a/gdb/jit.c
> +++ b/gdb/jit.c
> @@ -42,6 +42,7 @@
> #include "readline/tilde.h"
> #include "completer.h"
> #include <forward_list>
> +#include <map>
>
> static std::string jit_reader_dir;
>
> @@ -241,17 +242,11 @@ jit_reader_unload_command (const char *args, int from_tty)
> loaded_jit_reader = NULL;
> }
>
> -/* Per-program space structure recording which objfile has the JIT
> - symbols. */
> +/* Per-objfile structure recording JIT breakpoints. */
Just to help disambiguate, maybe precise here that we are talking about
the JIT-providing objfiles (those that define the magic interface
symbols), not the objfiles that are the result of the JIT.
>
> -struct jit_program_space_data
> +struct jit_objfile_bp
> {
> - /* The objfile. This is NULL if no objfile holds the JIT
> - symbols. */
> -
> - struct objfile *objfile = nullptr;
> -
> - /* If this program space has __jit_debug_register_code, this is the
> + /* If this objfile has __jit_debug_register_code, this is the
> cached address from the minimal symbol. This is used to detect
> relocations requiring the breakpoint to be re-created. */
>
> @@ -260,7 +255,17 @@ struct jit_program_space_data
> /* This is the JIT event breakpoint, or NULL if it has not been
> set. */
>
> - struct breakpoint *jit_breakpoint = nullptr;
> + breakpoint *jit_breakpoint = nullptr;
> +};
> +
> +/* Per-program space structure recording the objfiles and their JIT
> + symbols. */
> +
> +struct jit_program_space_data
> +{
> + /* The JIT breakpoint informations associated to objfiles. */
> +
> + std::map<objfile *, jit_objfile_bp> objfile_and_bps;
If we don't care about key ordering, I'd use an std::unordered_map.
But really, if we expect just to have a handful of items, it would probably
be more efficient to have a list or vector.
Also, given my comment on the following patch, I think we'll have to do
lookups by breakpoint address, so we would have to iterate on the maps items
anyway. Unless we use the breakpoint address as the key.
> };
>
> static program_space_key<jit_program_space_data> jit_program_space_key;
> @@ -332,9 +337,9 @@ get_jit_program_space_data ()
> memory. Returns 1 if all went well, 0 otherwise. */
>
> static int
> -jit_read_descriptor (struct gdbarch *gdbarch,
> - struct jit_descriptor *descriptor,
> - struct jit_program_space_data *ps_data)
> +jit_read_descriptor (gdbarch *gdbarch,
> + jit_descriptor *descriptor,
> + objfile *objf)
> {
> int err;
> struct type *ptr_type;
> @@ -344,17 +349,17 @@ jit_read_descriptor (struct gdbarch *gdbarch,
> enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
> struct jit_objfile_data *objf_data;
>
> - if (ps_data->objfile == NULL)
> + if (objf == nullptr)
> return 0;
I would probably change jit_read_descriptor to require a non-NULL objfile.
Simon
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