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Jit arm64 #6982

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@dstogov dstogov commented May 14, 2021

This is almost complete implementation of ARM64 back-end for PHP/JIT.

The JIT provides similar to x86[_64] speed improvement on Kunpeng 920 CPU (8-Cores, ARMv8, 2.60 GHz).
The following table shows execution time in seconds.

jit=0 jit=function jit=tracing
bench.php 0.387 0.152 0.130
micro_bench.php 2.278 1.521 1.273
Mandelbrot 0.074 0.033 0.014

In the current state all *.phpt tests are passed, symfony_demo is able to run with both functional and tracing JIT.

There are still some problems with long jumps patching in tracing JIT (it's limited to 1 MB for conditional and 128MB for unconditional branches). We are going to solve this soon.

Anyway, this is ready for review and seems good enough to be merged into master.

shqking and others added 30 commits May 14, 2021 11:04
SUMMARY

We implemented a prototype of PHP JIT/arm64. Briefly speaking,

1. build system
Changes to the build system are made so that PHP JIT can be successfully
built and run on ARM-based machine.
Major change lies in file zend_jit_arm64.dasc, where the handler for
each opcode is generated into machine code. Note that this file is just
copied from zend_jit_x86.dasc and the *unimplemented* parts are
substitued with 'brk' instruction for future work.

2. registers
AArch64 registers are defined in file zend_jit_arm64.h. From our
perspectives, the register usage is quite different from the x86
implementation due to the different ABI, number of registers and
addressing modes.
We had many confusions on this part, and will discuss it in details in
the final section.

3. opcodes
Several opcodes are partially supported, including INIT_FCALL, DO_UCALL,
DO_ICALL, RETURN, ADD, PRE_INC, JMP, QM_ASSIGN, etc. Hence, simple use
scenarios such as user function call, loops, addition with integer and
floating point numbers can be supported.
18 micro test cases are added under 'ext/opcache/tests/jit/arm64/'. Note
that majority of these test cases are design for functional JIT, and
cases 'hot_func_*.phpt' and 'loop_002.phpt' can trigger tracing JIT.

4. test
Our local test environment is an ARM-based server with Ubuntu 20.04 and
GCC-10. Note that both HYBRID and CALL VM modes are supported. We
suggest running the JIT test cases using the following command. Out of
all 130 test cases, 66 cases can be passed currently.
```
  $ make test TESTS='-d opcache.jit=1203 ext/opcache/tests/jit/'
```

DETAILS

1. I-cache flush
Instruction cache must be flushed for the JIT-ed code on AArch64. See
macro JIT_CACHE_FLUSH in file 'zend_jit_internal.h'.

2. Disassembler
Add initialization and jump target parse operations for AArch64 backed.
See the updates in file 'zend_jit_disasm.c'.

3. redzone
Enable redzone for AArch64. See the update in zend_vm_opcodes.h.
Redzone is designated to prevent 'vm_stack_data' from being optimized
out by compilers. It's worth noting that this 16-byte redzone might be
reused as temporary use(treated as extra stack space) for HYBRID mode.

4. stack space reservation
The definitions of HYBRID_SPAD, SPAD and NR_SPAD are a bit tricky for
x86/64.
In AArch64, HYBRID_SPAD and SPAD are both defined as 16. These 16 bytes
are pre-allocated for tempoerary usage along the exuection of JIT-ed
code. Take line 4185 in file zend_jit_arm64.dasc as an example. NR_SPAD
is defined as 48, out of which 32 bytes to save FP/IP/LR registers.
Note that we choose to always reserve HYBRID_SPAD bytes in HYBRID mode,
no matter whether redzone is used or not, for the sake of safety.

5. stack alignment
In AArch64 the stack pointer should be 16-byte aligned. Since shadow
stack is used for JIT, it's easy to guarantee the stack alignment, via
simply moving SP with an offset like 16 or a multiple of 16. That's why
NR_SPAD is defined as 48 and we use 32 of them to save FP/IP/LR
registers which only occupies 24 bytes.

6. global registers
x27 and x28 are reserved as global registers. See the updates in file
zend_jit_vm_helpers.c

7. function prologue for CALL mode
Two callee-saved registers x27 and x28 should saved in function
zend_jit_prologue() in file zend_jit_arm64.dasc. Besides the LR, i.e.
x30, should also be saved since runtime C helper functions(such as
zend_jit_find_func_helper) might be invoked along the execution of
JIT-ed code.

8. regset
Minor changes are done to regset operations particularly for AArch64.
See the updates in file zend_jit_internal.h.

REGISTER USAGE

In this section, we will first talk about our understanding on register
usage and then demonstrate our design.

1. Register usage for HYBRID/CALL modes
Registers are used similarly between HYBRID mode and CALL mode.

One difference is how FP and IP are saved. In HYBRID mode, they are
assigned to global registers, while in CALL mode they are saved/restored
on the VM stack explicitly in prologue/epilogue.

The other difference is that LR register should also be saved/restored
in CALL mode since JIT-ed code are invoked as normal functions.

2. Register usage for functional/tracing JIT
The way registers are used differs a lot between functional JIT and
tracing JIT.

For functional JIT, runtime C code (e.g. helper functions) would be
invoked along the execution of JIT-ed code. As the operands for *most*
opcodes are accessed via the stack slot, i.e. FP + offset. Hence there
is no need to save/restore local(caller-saved) registers before/after
invoking runtime C code.
Exception lies in Phi node and registers might be allocated for these
nodes. Currently I don't fully understand the reason, why registers are
allocated for Phi functions, because I suppose for different versions of
SSA variables at the Phi function, their postions on the stack slot
should be identical(in other words, access via the stack slot is enough
and there is no need to allocate registers).

For tracing JIT, runtime information are recorded for traces(before the
JIT compilation), and the data types and control flows are concrete as
well. Hence it's would be faster to conduct operations and computations
via registers rather than stack slots(as functional JIT does) for these
collected hot paths. Besides, runtime C code can be invoked for tracing
JIT, however this only happends for deoptimization and all registers are
saved to stack in advance.

3. Candidates for register allocator
1) opcode candidates
Function zend_jit_opline_supports_reg() determines the candidate opcodes
which can use CPU registers.

2) register candidates
Registers in set "ZEND_REGSET_FP + ZEND_REGSET_GP - ZEND_REGSET_FIXED -
ZEND_REGSET_PRESERVED" are available for register allocator.
Note that registers from ZEND_REGSET_FIXED are reserved for special
purpose, such as the stack pointer, and they are excluded from register
allocation process.
Note that registers from ZEND_REGSET_PRESERVED are callee-saved based on
the ABI and it's safe to not use them either.

4. Temporary registers
Temporary registers are needed by some opcodes to save intermediate
computation results.

1) Functions zend_jit_get_def_scratch_regset() and
zend_jit_get_scratch_regset() return which registers might be clobbered
by some opcodes. Hence register allocator would spill these scratch
registers if necessary when encountering these opcodes.

2) Macro ZEND_REGSET_LOW_PRIORITY denotes a set of registers which would
be allocated with low priority, and these registers can be used as
temporary usage to avoid conflicts to its best.

5. Compared to the x86 implementation, in JIT/arm64
1) Called-saved FP registers are included into ZEND_REGSET_PRESERVED for
AArch64.

2) We follow the logic of function zend_jit_opline_supports_reg().

3) We reserve 4 GPRs and 2 FPRs out from register allocator and use them
as temporary registers in particular. Note that these 6 registers are
included in set ZEND_REGSET_FIXED.
Since they are reserved, may-clobbered registers can be removed for most
opcodes except for function calls. Besides, low-priority registers are
defined as empty since all candidate registers are of the same priority.
See the updates in function zend_jit_get_scratch_regset() and macro
ZEND_REGSET_LOW_PRIORITY.

6. Why we reserve registers for temporary usage?
1) Addressing mode in AArch64 needs more temporary registers.
The addressing mode is different from x86 and tempory registers might be
*always* needed for most opcodes. For instance, an immediate must be
first moved into one register before storing into memory in AArch64,
whereas in x86 this immediate can be stored directly.

2) There are more registers in AArch64.
Compared to the solution in JIT/x86(that is, temporary registers are
reserved on demand, i.e. different registers for different opcodes under
different conditions), our solution seems a coarse-granularity and
brute-force solution, and the execution performance might be downgraded
to some extent since the number of candidate registers used for
allocation becomes less.
We suppose the performance loss might be acceptable since there are more
registers in AArch64.

3) Based on my understanding, scratch registers defined in x86 are
excluded from candidates for register allocator with *low possibility*,
and it can still allocate these registers. Special handling should be
conducted, such as checking 'reg != ZREG_R0'.
Hence, as we see it, it's simpler to reserve some temporary registers
exclusively. See the updates in function zend_jit_math_long_long() for
instance. TMP1 can be used directly without checking.

Co-Developed-by: Nick Gasson <Nick.Gasson@arm.com>
1. one **hybrid** solution of register usage
After the discussion with Dmitry, we may want to propose one hybrid
solution of register usage.

1) Following the x86 implementation, we define REG0/1/2 to be the
scratch registers. Clever tricks are utilized in x86 implementation for
better register allocation. Note that we define REG0/1/2 as x8/9/10. One
reason is that R0 and FCARG1 should be distinguished.

2) Temporary registers are also reserved(i.e. they are excluded from the
candidates of register allocator), and they would be used due to the
different addressing modes in AArch64.

2. update the 'make clean' target.

3. remove the unnecessary AArch64 related macros in zend_jit_internal.h.

[ci skip]

Change-Id: I627157b88b2344530d705751eb7f73a223ed83e5
CustomizedGitHooks: yes
Reference is involved in this test case, i.e. "$ref2 = & $ref1;".

1. Fix one bug in zend_do_fcall(). For each stack slot, the type
information gets initialized during the call frame allocation phase.

Opcode ZEND_ASSIGN_REF is associated to this statement. It's worth
noting that PHP JIT doesn't apply to this opcode actually. That means
the original handler(i.e. interpreter version) will be invoked at
runtime. Note that this mode works for a number of opcodes, not only
ZEND_ASSIGN_REF.

In the execution of original handler, the runtime type information of
$ref2 is accessed and this bug is triggered.

2. Support macros GET_Z_PTR and ZVAL_DEREF.

3. Cover new paths in function zend_jit_simple_assign() and macro
ZVAL_COPY_CONST.
Following the previous patch, we continue to support failed JIT test
cases involving reference.

In assign_010.phpt, major changes are done to support the assignment "$a
= $b" where "$b" is a reference.

Honestly speaking, I didn't fully understand the syntax here but rather
to translate the x86 implementation into AArch64.

Besides, test case assign_011.phpt would pass as well with this patch.
Support the case where arguments might be reference.

Besides, another two test cases, assign_019.phpt and assign_032.phpt,
would pass as well with this patch.
This patch is trivial, supporting the comparion with constant values,
i.e. "$i < 2" in this test case.
Support assginment with undefined variable, and a warning would be
emitted.

Besides, test case assign_023.phpt would pass as well with this patch.
Major changes are made to support statement "$a[0] = $unref", where
opcode ASSIGN_DIM is involved.

Besides, one bug in macro GC_DELREF is fixed. The reference count would
be further checked after decreasing in macro ZVAL_PTR_DTOR, hence,
instruction "subs" should be used to set the flags. After fixing this
bug, external function zend_jit_array_free() is used as the dtor for the
array "$a".
Major changes are:
1. Support opcode FETCH_DIM_W for "$arr[0][0] = $ref;" in the loop. See
the updates in function zend_jit_fetch_dim().
2. Spill the registers and store the values into memory. See the updates
in function zend_jit_spill_store(). This is done for Phi function.
3. Invoke function zend_array_destory() as dtor for arrays. This is done
by zend_jit_free_cv() when leaving the function foo().
For statement "$a = new stdClass;", opcode NEW is used and JIT would
invoke the original handler at runtime.

Our major changes are made to support statements "$a->a=1;" and
"$a->b=2;" where opcode ASSIGN_OBJ are used.
This test case covers one new path in macro TRY_ADDREF, touching macro
GC_ADDREF for the first time.
There are 6 user function calls in this test cases. The first 3
functions, i.e. foo(), foo1() and foo2(), can be supported already. In
this patch, we mainly focus on foo3(). Note that based on my test, once
foo3() gets supported, the remaining functions foo4() and foo5() can
pass as well.

Regarding function foo3(), we mainly focus on statement "$array = new
ArrayObject();", and the following two opcodes are involved.

  0009 V2 = NEW 0 string("ArrayObject")
  0010 DO_FCALL

Accordingly, functions zend_jit_handler(), zend_jit_cond_jmp() and
zend_jit_do_fcall() are invoked to generate the machine code. See the
handling process for case ZEND_NEW at file zend_jit.c. Hence, major
changes in this patch are made to support this statement.

Note that the updates at line 4840 in function zend_jit_do_fcall() are
made to support the later internal function call, i.e. var_dump().

Note that another test "noval_001.phpt" would pass with this patch as
well.
For function Foo(), the original handlers would be invoked for the first
two statements. And the third statement "$a = 42", where ASSIGN opcode
is involved, covers the cold code in function
zend_jit_assign_to_variable().

For function $main(), statement "var_dump(Foo::$prop);" covers a new
path in function zend_ jit_send_val() for SEND_VAL opcode.

Besides, another 2 test cases, i.e. fetch_dim_r_003.phpt and
fetch_dim_r_004.phpt, would pass as well with this patch.
This patch mainly supports the opcode FETCH_OBJ_R for statement
"$a->result = "okey";".
1. For statement "echo $a->test()", opcode INIT_METHOD_CALL is
involved. The updates in function zend_jit_init_method_call() and
zend_jit_push_call_frame() are made to support it.

2. The updates in function zend_jit_leave_func() are made to support the
RETURN opcode used in functions $closure and $test.

3. The updates in function zend_jit_assign_to_variable() are used to
support statement "$x = $arr".

4. The updates in function zend_jit_fetch_dimension_address_inner() and
zend_jit_simple_assign() are made to support statement "$x['a'] =
$closure()", where opcode ASSIGN_DIM is involved.
1. For statement "$a->change($a = array("a" => range(1, 5)));", the
following opcodes will be generated:

  0002 ASSIGN CV0($a) V1
  0003 INIT_METHOD_CALL 1 CV0($a) string("change")
  0004 INIT_NS_FCALL_BY_NAME 2 string("A\range")
  0005 SEND_VAL_EX int(1) 1
  0006 SEND_VAL_EX int(5) 2
  0007 V1 = DO_FCALL_BY_NAME

The updates in function zend_jit_init_fcall(), zend_jit_send_val() and
zend_jit_do_fcall() are made to support INIT_NS_FCALL_BY_NAME,
SEND_VAL_EX and DO_FCALL_BY_NAME respectively.

2. For method $change(), opcode RECV is used to obtain the argument:

  0000 #1.CV0($config) [rc1, rcn, array of [any, ref]] = RECV 1

Accordingly the updates in functions zend_jit_recv() and
zend_jit_verify_arg_type() are made.

3. For statement "array_keys($config["a"])", the following opcodes will
be generated:

  0001 INIT_NS_FCALL_BY_NAME 1 string("A\array_keys")
  0002 CHECK_FUNC_ARG 1
  0003 #3.V1 [ref, rc1, rcn, any] = FETCH_DIM_FUNC_ARG #1.CV0($config)
     ... -> #2.CV0($config) [rc1, rcn, ...
  0004 SEND_FUNC_ARG #3.V1 [ref, rc1, rcn, any] 1
  0005 #4.V1 [ref, rc1, rcn, any] = DO_FCALL_BY_NAME

CHECK_FUNC_ARG and SEND_FUNC_ARG are not supported before. See the
updates in functions zend_jit_check_func_arg() and zend_jit_send_var().

Besides, a new path is covered in macro OBJ_RELEASE when leaving.
The opcodes for function $foo are:

  0001 INIT_FCALL 1 96 string("var_dump")
  0002 #2.T1 [null, long] = FETCH_DIM_R array(...) #1.CV0($n) [...]
  0003 SEND_VAL #2.T1 [null, long] 1
  0004 DO_ICALL
  0005 RETURN null

Opcode FETCH_DIM_R is not touched before, and the updates in function
zend_jit_fetch_dim_read() are made to support it.
As different types of arguments are used for $foo, several cases in
function zend_jit_fetch_dimension_address_inner() are covered as well.

Besides, opcode DO_ICALL can reach one site of cold code in function
zend_jit_do_fcall().
Opcode FETCH_DIM_RW is not touched before and the udpates in function
zend_jit_fetch_dim() and zend_jit_fetch_dimension_address_inner() are
made to support it.

Besides, one new path is covered in function zend_jit_return() when
leaving.
Opcode ASSIGN_OBJ is generated for statement "$x->a = 1;" and one new
path in function zend_jit_assign_obj() is covered. Note that function
zend_jit_assign_to_variable_call() is invoked along this new path.

Besides, helper function zend_objects_store_del() is used as the dtor
for objects.
One new path is covered inside function zend_jit_fetch_obj() due to the
use of FETCH_OBJ_R opcode. Note that function zend_jit_zval_copy_deref()
is invoked along this new path.

Updates in function zend_jit_free() are made to support FREE opcode.

Stub function zend_jit_leave_function_stub() is touched for the first
time.
Opcode ASSIGN_OBJ_OP is used for statement "$x->a += 2;". The updates in
function zend_jit_assign_obj_op() are made to support this opcode.
Range checks are needed before encoding them into AArch64 instructions
as immediates.
Instruction is misused. 'dword', i.e. 32 bits, are loaded from memory.
Hence, 'ldr' should be used rather than 'ldrh'.
This test case is a big one. Major changes are:

1. statement "foo($obj->a)"
One new path is covered in function zend_jit_fetch_obj() for the
involved FETCH_OBJ_W opcode. See the update around label 5.
Opcode SEND_REF is used. The updates in function zend_jit_send_ref() are
made to support it. Note that macro FREE_OP is executed for the first
time. Temproray registers are passed since they are used inside. As a
result, its use sites are updated accordingly.

2. statement "$a = array()" in $foo2
One new path in function zend_jit_assign_to_variable() is covered.

3. statements involving variable $d in $bar
One new path in function zend_jit_fetch_obj() is covered. See the
updates around label 7.

Note that in macro EMALLOC, condition ZEND_DEBUG can be covered by DEBUG
build, i.e. "./configure --enable-debug".
Comparison between LONG and DOUBLE is (partially) supported in a similar
way to comparison between two LONG values. See the updates in function
zend_jit_cmp().

Key difference lies in handling NaN.

1. Instruction 'fcmp' is used to substitue 'ucomisd' in x86
implementation. Both of them raise invalid operation exception only when
either source operand is an SNaN.[1][2]

2. Parity flag is used in x86 to check whether either operand is NaN.[3]
I think this is QNaN case. As for AArch64, we use instruction 'bvs'.[4]

It's worthing noting that condition codes have different meanings for
floating-point comparions(e.g. 'fcmp')[4] compared to the
general-purpose comparisons(e.g. 'cmp').[5] For instance, 'b.hs' after
'fcmp' can check not only the cases "greater than, equal to" but also
the case "unordered"(that is NaN). We may simply treat it as a
combination of  'jae' and 'jp' in x86.

3. Instruction 'SETcc' is used in x86 for the case of ">=" or ">".
Note that flag "swap" is set in implementation, and it falls into cases
ZEND_IS_SMALLER or ZEND_IS_SMALLER_OR_EQUAL. We can use 'cset' in
AArch64.

However, it's weird that the NaN check is missing in x86. I suppose it
might be a bug. Take the case ">=" as an example. The two operands can
be  either DOUBLE + LONG or DOUBLE + DOUBLE. See the relevant code where
flag "swap" is set(i.e. function zend_jit_cmp_double_long() and function
zend_jit_cmp_double_double()). For the case "NaN >= 1.0", the expected
result should be FALSE, however, JIT/x86 would produce TRUE due to the
following "setae al". Unfortunately I haven't constructed one test case
to trigger that.

In our implementation, we choose to follow the case of "<" or "<=", and
I believe our implementation is safe anyway..

4. Temporary FP register is also needed and we reserve v16. See the
updates in file zend_jit_arm64.h.

5. Macro SET_ZVAL_TYPE_INFO_FROM_REG is misused in function
zend_jit_zval_copy_deref(). The second argument should be 32-bit long
and we fix it.

Note that simple test cases involving NaN are tested locally. I believe
it would get deeper testing by cmp_003.phpt(we will support it later).

[1]
https://developer.arm.com/documentation/dui0204/f/vector-floating-point-programming/vfp-instructions/fcmp?lang=en
[2] https://www.felixcloutier.com/x86/ucomisd
[3] https://en.wikipedia.org/wiki/Parity_flag
[4]
https://community.arm.com/developer/ip-products/processors/b/processors-ip-blog/posts/condition-codes-4-floating-point-comparisons-using-vfp
[5]
https://community.arm.com/developer/ip-products/processors/b/processors-ip-blog/posts/condition-codes-1-condition-flags-and-codes
'smart_branch_opcode' JMPZ is used in this test case. Similar to the
previous patch, I still didn't get why NaN check is missing for the
cases ">" and ">=". In our implementation, we add such checks.
The following opcodes would be generated for $foo:

  0000 #2.CV0($test) [bool] RANGE[0..1] = RECV 1
  0001 #3.CV1($x) [long] RANGE[MIN..MAX] = RECV 2
  0002 JMPZ #2.CV0($test) [bool] RANGE[0..1] BB4
  0003 #4.T2 [bool] ... = IS_SMALLER_OR_EQUAL int(1) #3.CV1($x) ...
  0004 JMP BB5
  ...

The updates in function zend_jit_verify_arg_type() are made to support
RECV opcode.

The updates in function zend_jit_bool_jmpznz() are made to support JMPZ
opcode.

New path is covered in functions zend_jit_cmp() and
zend_jit_cmp_long_long() for IS_SMALLER_OR_EQUAL opcode.
This test case is a big one. This patch mainly handles
smart_branch_opcode cases in function zend_jit_cmp_double_common().

Note that I failed to construct test cases to verify whether the missing
NaN check in x86 is buggy or not. One TODO is left to remind us when the
relevant code is touched.
@dstogov dstogov requested a review from nikic May 17, 2021 07:40
dstogov added 3 commits May 17, 2021 10:52
build with -d opcache.jit=1254 -d opcache.jit_hot_loop=1 -d
opcache.jit_hot_func=1 -d opcache.jit_hot_return=1 -d
opcache.jit_hot_side_exit=1)
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I think this looks okay at a high level -- I haven't looked at the arm64.dasc implementation in detail.

A general concern I have is that people working on x86 will not be able to easily make the ARM JIT work with their changes. Probably, it would fall to someone else to update it. Though it may help to include some instructions on how to setup cross-compilation and testing for ARM somewhere, as you already figured out how to do that...

Comment on lines +209 to +211
|.macro LOAD_ADDR, reg, addr
| // 48-bit virtual address
|| if (((uintptr_t)(addr)) == 0) {
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Suggested change
|.macro LOAD_ADDR, reg, addr
| // 48-bit virtual address
|| if (((uintptr_t)(addr)) == 0) {
|.macro LOAD_ADDR, reg, ptr
| // 48-bit virtual address
| uintptr_t addr = (uintptr_t) ptr;
|| if (addr == 0) {

etc. As this is repeated so many times, I think this would be nicer.

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I think it would also be good to assert here that the top 16 bit are zero, as the code assumes this. (It looks like newer ARM versions have extended address space from 2^48 to 2^52.)

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@shqking what do you suggest?

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Thanks for spotting that. Yes. I agree that one assertion should be added here. I will update it soon.
52-bit virtual address is supported in newer ARMv8.2-LVA (See https://opensource.com/article/20/12/52-bit-arm64-kernel). However to the best of my knowledge, there are few such chips in the market.
Java JDK currently only supports 48-bit virtual address, and I suppose putting an assertion might be one good option for now and we may want to support 52-bit address when needed in the future.

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But I don't think it would be a good solution to introduce a new variable inside the macro, i.e. uintptr_t addr = (uintptr_t) ptr;, which would lead to redefinition of addr for consecutive uses of macro LOAD_ADDR.

From my view, it's a problem to conduct the type conversion inside the definition of macro, or at all the callers of this macro. @dstogov May I have your opinion here?

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@shqking I afraid, assertion may conflict with "address tagging technology" (the high byte of the address may be ignored).

Introducing new variable would require wrapping macro into do { ... } while (0) block, or even C function. I prefer to think about this later.

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Yes. Agree. The higher bits might be used by some security features, e.g., MTE, PAC.

|.endmacro

|.macro LOAD_64BIT_VAL, reg, val
|| if (((uint64_t)(val)) == 0) {
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Same here, I would add uint64_t uval = (uint64_t) val to reduce noise.

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@nikic What noise do you mean? I don't see any warnings.
I agree with your suggestion, but I would prefer to change this after merging into master.

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((( Lisp noise :) But yes, no particular need to address before merging.

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dstogov commented May 18, 2021

I think this looks okay at a high level -- I haven't looked at the arm64.dasc implementation in detail.

A general concern I have is that people working on x86 will not be able to easily make the ARM JIT work with their changes. Probably, it would fall to someone else to update it. Though it may help to include some instructions on how to setup cross-compilation and testing for ARM somewhere, as you already figured out how to do that...

I'll publish an instruction at wiki.php.net

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dstogov commented May 18, 2021

Rebased and merged into master.

@dstogov dstogov closed this May 18, 2021
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dstogov commented May 18, 2021

@nikic https://wiki.php.net/internals/aarch64-cross-compile

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nikic commented May 18, 2021

It looks like there are some compiler warnings related to format strings: https://travis-ci.com/github/php/php-src/jobs/506179707#L1953

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dstogov commented May 18, 2021

Thanks for pointing. This is because we use libcapstone for disassemble on AArch64 (it also provides better output for x86). It seems, I forgot to test AArch64 without capstone and libudis86 doesn't support ARM of course. I'll try to fix this in an hour.

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dstogov commented May 19, 2021

@nikic ARM64 build without libcapstone should be fixed. I'm not sure how to trigger testing on travis-ci.com

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sebpop commented May 19, 2021

I'm not sure how to trigger testing on travis-ci.com

My colleague @janaknat can help set up travis-ci.com testing on Graviton2 arm64.

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I've created a PR to test with Graviton2 on Travis CI: #7016

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5 participants