On CHERI, and thus Arm's Morello prototype, pointers are represented as
hardware capabilities. These capabilities are comprised of not just an
integer address, as is the representation for traditional pointers, but
also bounds, permissions and other metadata, plus a tag bit used as the
validity bit, which provides fine-grained spatial and referential safety
for C and C++ in hardware. This tag bit is not part of the data itself
and is instead kept on the side, flowing with the capability between
registers and the memory subsystem, and any attempt to amplify the
privilege of or corrupt a capability clears this tag (or, in some cases,
traps), rendering them impossible to forge; you can only create
capabilities that are (possibly trivial) subsets of existing ones.
When the capability is stored in memory, this tag bit needs to be
preserved, which is done through the use of tagged memory. Every
capability-sized word gains an additional non-addressable (from the
CPU's perspective; depending on the implementation the tag bits may be
stored in a small block of memory carved out of normal DRAM that the CPU
is blocked from accessing) bit. This means that capabilities can only be
stored to aligned locations; attempting to store them to unaligned
locations will trap with an alignment fault or, if you end up using a
memcpy call, will copy the raw bytes of the capability's representation
but lose the tag, so when it is eventually loaded back as a capability
and dereferenced it will fault.
Since, on 64-bit architectures, our capabilities, used to implement C
language pointers, are 128-bit quantities, this means they need 16-byte
alignment. Currently the various #pragma pack directives, used to work
around (extremely broken and bogus) code that includes jsoncpp in a
context where the maximum alignment has been overridden, hard-code 8 as
the maximum alignment to use, and so do not sufficiently align CHERI /
Morello capabilities on 64-bit architectures. On Windows x64, the
default is also not 8 but 16 (ARM64 is supposedly 8), so this is
slightly dodgy to do there too, but in practice likely not an issue so
long as you don't use any 128-bit types there.
Instead of hard-coding a width, use a directive that resets the packing
back to the default. Unfortunately, whilst GCC and Clang both accept
using #pragma pack(push, 0) as shorthand like for any non-zero value,
MSVC does not, so this needs to be two directives.
CPPTL support is no longer relevant to JsonCpp, and can be removed from
the library. This patch removes all mentions of CPPTL, by removing all
definitions and code sections conditionally compiled only when JsonCpp
is used with CPPTL. Include guards are also renamed to not refer to
CPPTL where appropriate.
* Issue #958: Travis CI should enfore clang-format standards
This patch adds clang format support to the travis bots.
* Update path
* Roll back to version 8 since 9 is in test
* Cleanup clang
* Revert "Delete JSONCPP_DEPRECATED, use [[deprecated]] instead. (#978)" (#1029)
This reverts commit b27c83f691.
This patch fixes a build issue on CMake, presumably due to the new glibc
having a features.h include file. This patch renames our features.h file
to avoid a name collision.
* Cleanup versioning strategy
Currently, versioning is a mess. CMake and Meson have seperate build
version number storage locations, with no way of knowing you need to
have both. Plus, due to recent revisions the amalgamate script is broken
unless you build first, and may still be broken afterwards.
This PR fixes some issues with versioning, and adds comments clarifying
what has to be done when doing a release.
* Run clang format
* Update SOVERSION....
* Cleanup versioning strategy
Currently, versioning is a mess. CMake and Meson have seperate build
version number storage locations, with no way of knowing you need to
have both. Plus, due to recent revisions the amalgamate script is broken
unless you build first, and may still be broken afterwards.
This PR fixes some issues with versioning, and adds comments clarifying
what has to be done when doing a release.
* Run clang format
* Update SOVERSION....
This check replaces default bodies of special member functions with
= default;. The explicitly defaulted function declarations enable more
opportunities in optimization, because the compiler might treat
explicitly defaulted functions as trivial.
Additionally, the C++11 use of = default more clearly expreses the
intent for the special member functions.
SRCDIR=/Users/johnsonhj/src/jsoncpp/ #My local SRC
BLDDIR=/Users/johnsonhj/src/jsoncpp/cmake-build-debug/ #My local BLD
cd /Users/johnsonhj/src/jsoncpp/cmake-build-debug/
run-clang-tidy.py -extra-arg=-D__clang__ -checks=-*,modernize-use-equals-default -header-filter=.* -fix
Converts a default constructor’s member initializers into the new
default member initializers in C++11. Other member initializers that match the
default member initializer are removed. This can reduce repeated code or allow
use of ‘= default’.
SRCDIR=/Users/johnsonhj/src/jsoncpp/ #My local SRC
BLDDIR=/Users/johnsonhj/src/jsoncpp/cmake-build-debug/ #My local BLD
cd /Users/johnsonhj/src/jsoncpp/cmake-build-debug/
run-clang-tidy.py -extra-arg=-D__clang__ -checks=-*,modernize-use-default-member-init -header-filter=.* -fix
The check converts the usage of null pointer constants (eg. NULL, 0) to
use the new C++11 nullptr keyword.
SRCDIR=/Users/johnsonhj/src/jsoncpp #My local SRC
BLDDIR=/Users/johnsonhj/src/jsoncpp/cmake-build-debug/ #My local BLD
cd /Users/johnsonhj/src/jsoncpp/cmake-build-debug/
run-clang-tidy.py -extra-arg=-D__clang__ -checks=-*,modernize-use-nullptr -header-filter=.* -fix
Introduce 'allowSpecialFloats' for readers and 'useSpecialFloats' for writers, use consistent macro snprintf definition for writers and readers, provide new unit tests for #209
