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Unicorn CPU emulator framework (ARM, AArch64, M68K, Mips, Sparc, X86)
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Eric Blake e096e62127
qapi: Don't box branches of flat unions
There's no reason to do two malloc's for a flat union; let's just
inline the branch struct directly into the C union branch of the
flat union.

Surprisingly, fewer clients were actually using explicit references
to the branch types in comparison to the number of flat unions
thus modified.

This lets us reduce the hack in qapi-types:gen_variants() added in
the previous patch; we no longer need to distinguish between
alternates and flat unions.

The change to unboxed structs means that u.data (added in commit
cee2dedb) is now coincident with random fields of each branch of
the flat union, whereas beforehand it was only coincident with
pointers (since all branches of a flat union have to be objects).
Note that this was already the case for simple unions - but there
we got lucky. Remember, visit_start_union() blindly returns true
for all visitors except for the dealloc visitor, where it returns
the value !!obj->u.data, and that this result then controls
whether to proceed with the visit to the variant. Pre-patch,
this meant that flat unions were testing whether the boxed pointer
was still NULL, and thereby skipping visit_end_implicit_struct()
and avoiding a NULL dereference if the pointer had not been
allocated. The same was true for simple unions where the current
branch had pointer type, except there we bypassed visit_type_FOO().
But for simple unions where the current branch had scalar type, the
contents of that scalar meant that the decision to call
visit_type_FOO() was data-dependent - the reason we got lucky there
is that visit_type_FOO() for all scalar types in the dealloc visitor
is a no-op (only the pointer variants had anything to free), so it
did not matter whether the dealloc visit was skipped. But with this
patch, we would risk leaking memory if we could skip a call to
visit_type_FOO_fields() based solely on a data-dependent decision.

But notice: in the dealloc visitor, visit_type_FOO() already handles
a NULL obj - it was only the visit_type_implicit_FOO() that was
failing to check for NULL. And now that we have refactored things to
have the branch be part of the parent struct, we no longer have a
separate pointer that can be NULL in the first place. So we can just
delete the call to visit_start_union() altogether, and blindly visit
the branch type; there is no change in behavior except to the dealloc
visitor, where we now unconditionally visit the branch, but where that
visit is now always safe (for a flat union, we can no longer
dereference NULL, and for a simple union, visit_type_FOO() was already
safely handling NULL on pointer types).

Unfortunately, simple unions are not as easy to switch to unboxed
layout; because we are special-casing the hidden implicit type with
a single 'data' member, we really DO need to keep calling another
layer of visit_start_struct(), with a second malloc; although there
are some cleanups planned for simple unions in later patches.

visit_start_union() and gen_visit_implicit_struct() are now unused.
Drop them.

Note that after this patch, the only remaining use of
visit_start_implicit_struct() is for alternate types; the next patch
will do further cleanup based on that fact.

Backports commit 544a3731591f5d53e15f22de00ce5ac758d490b3 from qemu
2018-02-20 16:44:55 -05:00
bindings link to Crystal binding 2017-12-23 00:26:40 +08:00
docs Added note about installing tests dependencies on Mac OS X. Added note about tests failing when required architecture support is disabled in build. () 2017-10-12 19:56:00 +08:00
include include: Move RAMList to ramlist.h 2018-02-20 08:47:51 -05:00
msvc qapi-visit: Less indirection in visit_type_Foo_fields() 2018-02-20 16:00:37 -05:00
qemu qapi: Don't box branches of flat unions 2018-02-20 16:44:55 -05:00
samples Fixed register mistake in comments () 2017-09-17 16:40:01 +07:00
tests add 64-bit test demonstrating setting MSRs and FS/GS segments () 2017-09-29 04:26:23 +08:00
.appveyor.yml MSYS test () 2017-06-25 10:11:35 +08:00
.gitignore arm64eb: add support for ARM64 big endian. 2017-04-24 23:30:01 +08:00
.travis.yml use new travis osx image and brew () 2018-01-05 10:29:49 +08:00
AUTHORS.TXT import 2015-08-21 15:04:50 +08:00
Brewfile Update Brewfile 2017-09-30 17:36:44 +07:00
ChangeLog update ChangeLog 2017-04-20 13:28:02 +08:00
config.mk Fix document file extension 2016-08-08 17:33:49 +09:00
COPYING import 2015-08-21 15:04:50 +08:00
COPYING.LGPL2 LGPL2 for all header files under include/unicorn/ 2017-12-16 10:08:42 +08:00
COPYING_GLIB glib_compat: add COPYING_GLIB 2016-12-27 10:15:08 +08:00
CREDITS.TXT update CREDITS.TXT 2017-04-25 12:56:47 +08:00
install-cmocka-linux.sh Start moving examples in S files () 2017-06-25 10:14:22 +08:00
list.c callback to count number of instructions in uc_emu_start() should be executed first. fix 2017-06-16 13:22:38 +08:00
make.sh Added MSVC support for arm64eb. 2017-04-25 14:23:58 +10:00
Makefile crypto: introduce new module for computing hash digests 2018-02-17 15:23:17 -05:00
msvc.bat add msvc.bat 2017-04-21 15:35:40 +08:00
pkgconfig.mk bump extra version to 2 2017-04-21 15:30:40 +08:00
README.md add Clojure 2017-12-23 00:32:33 +08:00
uc.c uc: Handle freeing of multiple address spaces 2018-02-18 21:36:50 -05:00
windows_export.bat Make the call out to visual studio extremely resilient 2017-01-02 03:32:48 -08:00

Unicorn Engine

Join the chat at https://gitter.im/unicorn-engine/chat

Build Status Build status

Unicorn is a lightweight, multi-platform, multi-architecture CPU emulator framework based on QEMU.

Unicorn offers some unparalleled features:

  • Multi-architecture: ARM, ARM64 (ARMv8), M68K, MIPS, SPARC, and X86 (16, 32, 64-bit)
  • Clean/simple/lightweight/intuitive architecture-neutral API
  • Implemented in pure C language, with bindings for Crystal, Clojure, Visual Basic, Perl, Rust, Ruby, Python, Java, .NET, Go, Delphi/Free Pascal and Haskell.
  • Native support for Windows & *nix (with Mac OSX, Linux, *BSD & Solaris confirmed)
  • High performance via Just-In-Time compilation
  • Support for fine-grained instrumentation at various levels
  • Thread-safety by design
  • Distributed under free software license GPLv2

Further information is available at http://www.unicorn-engine.org

License

This project is released under the GPL license.

Compilation & Docs

See docs/COMPILE.md file for how to compile and install Unicorn.

More documentation is available in docs/README.md.

Contact

Contact us via mailing list, email or twitter for any questions.

Contribute

If you want to contribute, please pick up something from our Github issues.

We also maintain a list of more challenged problems in a TODO list.

CREDITS.TXT records important contributors of our project.