If an op with dead outputs is not removed, because it has side effects
or has multiple output and only one dead, mark the registers as dead
instead of saving them. This avoid a few register spills on TCG targets
with low register count, especially with div2 and mul2 ops, or when a
qemu_ld* result is not used (prefetch emulation for example).
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
If an op is not removed and has dead output arguments, mark it
in op_dead_args similarly to what is done for input arguments.
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Allow all args to be dead by replacing the input specific op_dead_iargs
variable by op_dead_args. Note this is a purely mechanical change.
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Although the TCG generated code is always in ARM mode, it is possible
that the host code was compiled by gcc in Thumb mode (this is often the
default for Linux distributions targeting ARM v7 only). Handle this
by using BLX imm when doing a call from ARM into Thumb mode.
Since BLX imm is not a conditionalisable instruction, we make
tcg_out_call() no longer take a condition code; we were only ever
using it with COND_AL anyway.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Andrzej Zaborowski <andrew.zaborowski@intel.com>
Add support (if CONFIG_DEBUG_TCG is defined) for debugging leakage
of temporary variables. Generally any temporaries created by
a target while it is translating an instruction should be freed
by the end of that instruction; otherwise carefully crafted
guest code could cause TCG to run out of temporaries and assert.
By calling tcg_check_temp_count() after each instruction we can
check that we are not leaking temporaries in this way.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Add a comment about cache coherency and retranslation, so that people
developping new targets based on existing ones are warned of the issue.
Acked-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Improve constant loading in two ways:
- On all ARM versions, it's possible to load 0xffffff00 = -0x100 using
the mvn rd, #0. Fix the conditions.
- On <= ARMv6 versions, where movw and movt are not available, load the
constants using mov and orr with rotations depending on the constant
to load. This is very useful for example to load constants where the
low byte is 0. This reduce the generated code size by about 7%.
Also fix the coding style at the same time.
Cc: Andrzej Zaborowski <balrog@zabor.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
TCG on MIPS was trying to avoid changing the branch offset, but didn't
due to a stupid typo. Fix it.
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Due to a typo, qemu_st64 doesn't properly byteswap the 32-bit low word of
a 64 bit word before saving it. This patch fixes that.
Acked-by: Andrzej Zaborowski <balrogg@gmail.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
QEMU uses code retranslation to restore the CPU state when an exception
happens. For it to work the retranslation must not modify the generated
code. This is what is currently implemented in ARM TCG.
However on CPU that don't have icache/dcache/memory synchronised like
ARM, this requirement is stronger and code retranslation must not modify
the generated code "atomically", as the cache line might be flushed
at any moment (interrupt, exception, task switching), even if not
triggered by QEMU. The probability for this to happen is very low, and
depends on cache size and associativiy, machine load, interrupts, so the
symptoms are might happen randomly.
This requirement is currently not followed in tcg/arm, for the
load/store code, which basically has the following structure:
1) tlb access code is written
2) conditional fast path code is written
3) branch is written with a temporary target
4) slow path code is written
5) branch target is updated
The cache lines corresponding to the retranslated code is not flushed
after code retranslation as the generated code is supposed to be the
same. However if the cache line corresponding to the branch instruction
is flushed between step 3 and 5, and is not flushed again before the
code is executed again, the branch target is wrong. In the guest, the
symptoms are MMU page fault at a random addresses, which leads to
kernel page fault or segmentation faults.
The patch fixes this issue by avoiding writing the branch target until
it is known, that is by writing only the branch instruction first, and
later only the offset.
This fixes booting linux guests on ARM hosts (tested: arm, i386, mips,
mipsel, sh4, sparc).
Acked-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
The usermode version of qemu_ld doesn't used mem_index,
leading to set-but-not-used warnings.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Edgar E. Iglesias <edgar@axis.com>
A typo in the usermode address calculation path; R3 used where R2 needed.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Edgar E. Iglesias <edgar@axis.com>
Use ld4 not ld8 for reading the tlb of 32-bit targets.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Edgar E. Iglesias <edgar@axis.com>
The port was not properly merged following
86feb1c860
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Edgar E. Iglesias <edgar@axis.com>
Fix compilation error when GUEST_BASE is not defined.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Edgar E. Iglesias <edgar@axis.com>
The arguments to tcg_gen_helper32 for these functions were not
updated correctly in rev 2bece2c883.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Edgar E. Iglesias <edgar@axis.com>
fprintf_function uses format checking with GCC_FMT_ATTR.
Cc: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
When qemu is configured with --enable-debug-tcg,
gcc throws this warning (or error with -Werror):
tcg/tcg.c:1030: error: comparison of unsigned expression >= 0 is always true
Fix it by removing the >= 0 part.
The type cast to 'unsigned' catches negative values of op
(which should never happen).
This is a modification of Hollis Blanchard's patch.
Cc: Hollis Blanchard <hollis@penguinppc.org>
Cc: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
3b6dac3416 apparently broke the ppc64 TCG target
compilation in the code path without guest base.
Reverting this line fixes the build.
Signed-off-by: Andreas F?rber <andreas.faerber@web.de>
Cc: malc <av1474@comtv.ru>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Richard Henderson <rth@twiddle.net>
Signed-off-by: malc <av1474@comtv.ru>
5da79c86a3 broke compilation on Mac OS X v10.5 ppc.
Apple's GCC 4.0.1 does not define _CALL_DARWIN. Recognize __APPLE__ again as well.
Signed-off-by: Andreas F?rber <andreas.faerber@web.de>
Cc: malc <av1474@comtv.ru>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: J?rgen Lock <nox@jelal.kn-bremen.de>
Cc: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: malc <av1474@comtv.ru>
Original patch from Ulrich Hecht, further work from Alexander Graf
and Richard Henderson.
Cc: Ulrich Hecht <uli@suse.de>
Cc: Alexander Graf <agraf@suse.de>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
We need not reserve the register unless we're going to use it.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: malc <av1474@comtv.ru>
Some hosts (amd64, ia64) have an ABI that ignores the high bits
of the 64-bit register when passing 32-bit arguments. Others
require the value to be properly sign-extended for the type.
I.e. "int32_t" must be sign-extended and "uint32_t" must be
zero-extended to 64-bits.
To effect this, extend the "sizemask" parameter to tcg_gen_callN
to include the signedness of the type of each parameter. If the
tcg target requires it, extend each 32-bit argument into a 64-bit
temp and pass that to the function call.
This ABI feature is required by sparc64, ppc64 and s390x.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Before gcc 4.2, __builtin___clear_cache doesn't exist, and
afterward the gcc s390 backend implements it as nothing.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Both tcg_target_init and tcg_target_qemu_prologue
are unused outside of tcg.c.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Mirror tcg_out_movi in having a TYPE parameter. This allows x86_64
to perform the move at the proper width, which may elide a REX prefix.
Introduce a TCG_TYPE_REG enumerator to represent the "native width"
of the host register, and to distinguish the usage from "pointer data"
as represented by the existing TCG_TYPE_PTR.
Update all targets to match.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Make fallthru be TLB hit and branch be TLB miss. Doing this
both improves branch prediction and will allow further cleanup.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Splitting out these functions will allow further cleanups.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Include it in the opcode as an extension, as with P_EXT
or the REX bits in the x86-64 port.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
(1) The output registers were not marked call-clobbered, even though
they can be modified by called functions.
(2) The thread pointer was not marked reserved.
(3) R4-R6 are call-saved, but not saved by the prologue. Rather than
save them, mark them reserved so that we don't use them.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Now that the prologue is generated after GUEST_BASE is fixed,
we can load it as an immediate, and also avoid reserving the
register if it isn't necessary.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
