__builtin_unreachable doesn't raise any compile-time warnings/errors on its
own, so problems with its usage can't be easily detected. While it would be
nice for this situation to change and compilers to at least add a warning
for trivial cases where local state means the instruction can't be reached,
this isn't the case at the moment and likely will not happen.
This commit adds an __assert_unreachable, whose intent is incredibly clear:
it asserts that this instruction is unreachable. On INVARIANTS builds, it's
a panic(), and on non-INVARIANTS it expands to __unreachable().
Existing users of __unreachable() are converted to __assert_unreachable,
to improve debuggability if this assumption is violated.
Reviewed by: mjg
Differential Revision: https://reviews.freebsd.org/D23793
in practice).
db_expr_t is a signed type, but right shifts are fudged to evaluate
them in an unsigned type, and the unsigned type was broken by hard-
coding it as 'unsigned', so casting to it lost the top bits on arches
with db_expr_t larger than u_int.
The unsigned type with the same size as db_expr_t is not declared;
assume that db_addr_t gives it. Fixing this properly is less important
than using the correct type for db_expr_t (originally always long for
C90, but always intmax_t since C99).
and negative shift counts.
Fix error messages: print "Division" instead of "Divide"; print
multiplier-like, addition-like and logical operator tokens instead of
garbage (usually the command name).
ddb has a primitive lexer with excessive information hiding that makes
it hard to find even the point in the line where a syntax error is
detected. Old ddb just printed "Syntax error" and this was unimproved
in most places by printing a garbage token.
This are based on Mach3.
Documentation is pending but has been promised.
Submitted by: Dan Partelly
Reviewed by: adrian, jhb (older version)
Differential Revision: https://reviews.freebsd.org/D4230
RelNotes: yes
The replacement started at r283088 was necessarily incomplete without
replacing boolean_t with bool. This also involved cleaning some type
mismatches and ansifying old C function declarations.
Pointed out by: bde
Discussed with: bde, ian, jhb
(DPCPU), as suggested by Peter Wemm, and implement a new per-virtual
network stack memory allocator. Modify vnet to use the allocator
instead of monolithic global container structures (vinet, ...). This
change solves many binary compatibility problems associated with
VIMAGE, and restores ELF symbols for virtualized global variables.
Each virtualized global variable exists as a "reference copy", and also
once per virtual network stack. Virtualized global variables are
tagged at compile-time, placing the in a special linker set, which is
loaded into a contiguous region of kernel memory. Virtualized global
variables in the base kernel are linked as normal, but those in modules
are copied and relocated to a reserved portion of the kernel's vnet
region with the help of a the kernel linker.
Virtualized global variables exist in per-vnet memory set up when the
network stack instance is created, and are initialized statically from
the reference copy. Run-time access occurs via an accessor macro, which
converts from the current vnet and requested symbol to a per-vnet
address. When "options VIMAGE" is not compiled into the kernel, normal
global ELF symbols will be used instead and indirection is avoided.
This change restores static initialization for network stack global
variables, restores support for non-global symbols and types, eliminates
the need for many subsystem constructors, eliminates large per-subsystem
structures that caused many binary compatibility issues both for
monitoring applications (netstat) and kernel modules, removes the
per-function INIT_VNET_*() macros throughout the stack, eliminates the
need for vnet_symmap ksym(2) munging, and eliminates duplicate
definitions of virtualized globals under VIMAGE_GLOBALS.
Bump __FreeBSD_version and update UPDATING.
Portions submitted by: bz
Reviewed by: bz, zec
Discussed with: gnn, jamie, jeff, jhb, julian, sam
Suggested by: peter
Approved by: re (kensmith)
the indirection operator ('*') and address examination ('x/a') on
big-endian platoforms for which the above is not true, as well as on
little-endian platforms if the cut-off bits are not 0.
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
to get the prototypes.
Changed some `int's to `boolean_t's. boolean_t's are ints so they are
hard to distinguish from ints.
Converted function headers to old-style. ddb is written in K&R1 C
except where we broke it.
``changes'' are actually not changes at all, but CVS sometimes has trouble
telling the difference.
This also includes support for second-directory compiles. This is not
quite complete yet, as `config' doesn't yet do the right thing. You can
still make it work trivially, however, by doing the following:
rm /sys/compile
mkdir /usr/obj/sys/compile
ln -s M-. /sys/compile
cd /sys/i386/conf
config MYKERNEL
cd ../../compile/MYKERNEL
ln -s /sys @
rm machine
ln -s @/i386/include machine
make depend
make
