The value returned from tcg_qemu_tb_exec() is the value passed to the
corresponding tcg_gen_exit_tb() at translation time of the last TB
attempted to execute. It is a little confusing to store it in a variable
named 'next_tb'. In fact, it is a combination of 4-byte aligned pointer
and additional information in its two least significant bits. Break it
down right away into two variables named 'last_tb' and 'tb_exit' which
are a pointer to the last TB attempted to execute and the TB exit
reason, correspondingly. This simplifies the code and improves its
readability.
Correct a misleading documentation comment for tcg_qemu_tb_exec() and
fix logging in cpu_tb_exec(). Also rename a misleading 'next_tb' in
another couple of places.
Backports commit 819af24b9c1e95e6576f1cefd32f4d6bf56dfa56 from qemu
In user mode, there's only a static address translation, TBs are always
invalidated properly and direct jumps are reset when mapping change.
Thus the destination address is always valid for direct jumps and
there's no need to restrict it to the pages the TB resides in.
Backports commit 90aa39a1cc4837360889f0e033ca25cc82100308 from qemu
We don't take care of direct jumps when address mapping changes. Thus we
must be sure to generate direct jumps so that they always keep valid
even if address mapping changes. Luckily, we can only allow to execute a
TB if it was generated from the pages which match with current mapping.
Document tcg_gen_goto_tb() declaration and note the reason for
destination PC limitations.
Some targets with variable length instructions allow TB to straddle a
page boundary. However, we make sure that both of TB pages match the
current address mapping when looking up TBs. So it is safe to do direct
jumps into the both pages. Correct the checks for some of those targets.
Given that, we can safely patch a TB which spans two pages. Remove the
unnecessary check in cpu_exec() and allow such TBs to be patched.
Backports commit 5b053a4a28278bca606eeff7d1c0730df1b047e9 from qemu
Briefly describe in a comment how direct block chaining is done. It
should help in understanding of the following data fields.
Rename some fields in TranslationBlock and TCGContext structures to
better reflect their purpose (dropping excessive 'tb_' prefix in
TranslationBlock but keeping it in TCGContext):
tb_next_offset => jmp_reset_offset
tb_jmp_offset => jmp_insn_offset
tb_next => jmp_target_addr
jmp_next => jmp_list_next
jmp_first => jmp_list_first
Avoid using a magic constant as an invalid offset which is used to
indicate that there's no n-th jump generated.
Backports commit f309101c26b59641fc1aa8fb2a98a5441cdaea03 from qemu
Ensure direct jump patching in MIPS is atomic by using
atomic_read()/atomic_set() for code patching.
Backports commit c82460a560176ef69c2f0662bd280612e274db96 from qemu
Ensure direct jump patching in SPARC is atomic by using
atomic_read()/atomic_set() for code patching.
Backports commit 84f79fb7c6e857edc807e4a251338243ce0cbac3 from qemu
Ensure direct jump patching in AArch64 is atomic by using
atomic_read()/atomic_set() for code patching.
Backports commit 9e269112953be4d670cb0d25042bd6546fcf3e45 from qemu
Ensure direct jump patching in ARM is atomic by using
atomic_read()/atomic_set() for code patching.
Backports commit 7d14e0e2d661479985197203589c38840e1066df from qemu
Ensure direct jump patching in s390 is atomic by:
* naturally aligning a location of direct jump address;
* using atomic_read()/atomic_set() for code patching.
Backports commit ed3d51ecd7fe248d3959e469d53890ac9ffe0cd2 from qemu
Ensure direct jump patching in i386 is atomic by:
* naturally aligning a location of direct jump address;
* using atomic_read()/atomic_set() for code patching.
Backports commit 0d07abf05e98903c7faf204a9a90f7d45b7554dc from qemu
Add tcg_set_insn_param as a mechanism to modify an insn
parameter after emiting the insn. This is useful for icount
and also for embedding fault information for a specific insn.
Backports commit 1d41478fd428e01f057d3248292e4cdcdb048523 from qemu
The TCG code is quite performance sensitive, but at the same time can
also be quite tricky. That is why asserts that can be enabled with the
--enable-debug-tcg configure option.
This used to work the following way:
| #include "config.h"
|
| ...
|
| #if !defined(CONFIG_DEBUG_TCG) && !defined(NDEBUG)
| /* define it to suppress various consistency checks (faster) */
| #define NDEBUG
| #endif
|
| ...
|
| #include <assert.h>
Since commit 757e725b (tcg: Clean up includes) "config.h" as been
replaced by "qemu/osdep.h" which itself includes <assert.h>. As a
consequence the assertions are always enabled, even when using
--disable-debug-tcg, causing a performance regression, especially on
targets with many registers. For instance on qemu-system-ppc the
speed difference is about 15%.
tcg_debug_assert is controlled directly by CONFIG_DEBUG_TCG and already
uses in some places. This patch replaces all the calls to assert into
calss to tcg_debug_assert.
Backports commit eabb7b91b36b202b4dac2df2d59d698e3aff197a from qemu
The MIPS TCG backend is the only one to have
tcg_target_reg_alloc_order[] elements of type TCGReg rather than int.
This resulted in commit 91478cefaaf2 ("tcg: Allocate indirect_base
temporaries in a different order") breaking the build on MIPS since the
type differed from indirect_reg_alloc_order[]:
tcg/tcg.c:1725:44: error: pointer type mismatch in conditional expression [-Werror]
order = rev ? indirect_reg_alloc_order : tcg_target_reg_alloc_order;
^
Make it an array of ints to fix the build and match other architectures.
Backports commit 2dc7553d0c0a3915c649e1a91b0f0be70b4674b3 from qemu
qemu-log: dfilter-ise exec, out_asm, op and opt_op
This ensures the code generation debug code will honour -dfilter if set.
For the "exec" tracing I've added a new inline macro for efficiency's
sake.
Backports commit d977e1c2dbc9e63454b2000f91954d02543bf43b from qemu
My later debugging patches need access to the origin PC which is held in
the TranslationBlock structure. Pass down the whole structure as it also
holds the information about the code start point.
Backports commit 5bd2ec3d7b47b2252745882795d79aef36380fb7 from qemu
Move declarations out of qemu-common.h for functions declared in
utils/ files: e.g. include/qemu/path.h for utils/path.c.
Move inline functions out of qemu-common.h and into new files (e.g.
include/qemu/bcd.h)
Backports commit f348b6d1a53e5271cf1c9f9acc4646b4b98c1771 from qemu
The target-dependant type TCGv must be defined in "tcg/tcg.h" before
including the tracing helper wrappers in "tcg/tcg-op.h".
It also makes more sense to define it here, where other TCG types are
defined too.
Backports commit 5d4e1a1081d3f1ec2908ff0eaebe312389971ab4 from qemu
Adds the 'TCGv_env' type for pointers to 'CPUArchState' objects. The
tracing infrastructure later needs to differentiate between regular
pointers and pointers to vCPUs.
Also changes all targets to use the new 'TCGv_env' type instead of the
generic 'TCGv_ptr'. As of now, the change is merely cosmetic ('TCGv_env'
translates into 'TCGv_ptr'), but that could change in the future to
enforce the difference.
Note that a 'TCGv_env' type (for 'CPUState') is not added, since all
helpers currently receive the architecture-specific
pointer ('CPUArchState').
Backports commit 1bcea73e13b2b059d0cb3301aeaca43e5656ef57 from qemu
Commit 757e725b58c57d added a number of #include "qemu/osdep.h"
files to the tcg-target.c files (as they were named at the time).
These are unnecessary because these files are not standalone C
files, and the tcg/tcg.c file which includes them will have
already included osdep.h on their behalf. Remove the unneeded
include directives.
Backports commit c3b7f66800fbf9f47fddbcf2e2cd30ea932e0aae from qemu
Rename the per-architecture tcg-target.c files to tcg-target.inc.c.
This makes it clearer that they are not intended to be standalone
C files, but are instead #included into another source file.
Backports commit ce151109813e2770fd3cee2f37bfa2cdd01a12b9 from qemu
