diff options
| -rw-r--r-- | gdb/ChangeLog | 6 | ||||
| -rw-r--r-- | gdb/gdbtypes.c | 11 | ||||
| -rw-r--r-- | gdb/gdbtypes.h | 47 |
3 files changed, 39 insertions, 25 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog index f0338a2..380ff42 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,9 @@ +2015-07-28 Simon Marchi <simon.marchi@ericsson.com> + + * gdbtypes.c (type_length_units): New function. + * gdbtypes.h (type_length_units): New declaration. + (struct type) <length>: Update comment. + 2015-07-27 Simon Marchi <simon.marchi@ericsson.com> * valprint.c (generic_val_print): Factor out complex diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c index 3f1f3fb..e6a9547 100644 --- a/gdb/gdbtypes.c +++ b/gdb/gdbtypes.c @@ -252,6 +252,17 @@ get_target_type (struct type *type) return type; } +/* See gdbtypes.h. */ + +unsigned int +type_length_units (struct type *type) +{ + struct gdbarch *arch = get_type_arch (type); + int unit_size = gdbarch_addressable_memory_unit_size (arch); + + return TYPE_LENGTH (type) / unit_size; +} + /* Alloc a new type instance structure, fill it with some defaults, and point it at OLDTYPE. Allocate the new type instance from the same place as OLDTYPE. */ diff --git a/gdb/gdbtypes.h b/gdb/gdbtypes.h index c166e48..f270855 100644 --- a/gdb/gdbtypes.h +++ b/gdb/gdbtypes.h @@ -780,31 +780,23 @@ struct type check_typedef. */ int instance_flags; - /* * Length of storage for a value of this type. This is what - sizeof(type) would return; use it for address arithmetic, memory - reads and writes, etc. This size includes padding. For example, - an i386 extended-precision floating point value really only - occupies ten bytes, but most ABI's declare its size to be 12 - bytes, to preserve alignment. A `struct type' representing such - a floating-point type would have a `length' value of 12, even - though the last two bytes are unused. - - There's a bit of a host/target mess here, if you're concerned - about machines whose bytes aren't eight bits long, or who don't - have byte-addressed memory. Various places pass this to memcpy - and such, meaning it must be in units of host bytes. Various - other places expect they can calculate addresses by adding it - and such, meaning it must be in units of target bytes. For - some DSP targets, in which HOST_CHAR_BIT will (presumably) be 8 - and TARGET_CHAR_BIT will be (say) 32, this is a problem. - - One fix would be to make this field in bits (requiring that it - always be a multiple of HOST_CHAR_BIT and TARGET_CHAR_BIT) --- - the other choice would be to make it consistently in units of - HOST_CHAR_BIT. However, this would still fail to address - machines based on a ternary or decimal representation. */ - - unsigned length; + /* * Length of storage for a value of this type. The value is the + expression in host bytes of what sizeof(type) would return. This + size includes padding. For example, an i386 extended-precision + floating point value really only occupies ten bytes, but most + ABI's declare its size to be 12 bytes, to preserve alignment. + A `struct type' representing such a floating-point type would + have a `length' value of 12, even though the last two bytes are + unused. + + Since this field is expressed in host bytes, its value is appropriate + to pass to memcpy and such (it is assumed that GDB itself always runs + on an 8-bits addressable architecture). However, when using it for + target address arithmetic (e.g. adding it to a target address), the + type_length_units function should be used in order to get the length + expressed in target addressable memory units. */ + + unsigned int length; /* * Core type, shared by a group of qualified types. */ @@ -1659,6 +1651,11 @@ extern struct gdbarch *get_type_arch (const struct type *); extern struct type *get_target_type (struct type *type); +/* Return the equivalent of TYPE_LENGTH, but in number of target + addressable memory units of the associated gdbarch instead of bytes. */ + +extern unsigned int type_length_units (struct type *type); + /* * Helper function to construct objfile-owned types. */ extern struct type *init_type (enum type_code, int, int, const char *, |