Previously, YJIT assumed that basic blocks never consume more than
1 KiB of memory. This assumption does not hold for long Ruby methods
such as the one in the following:
```ruby
eval(<<RUBY)
def set_local_a_lot
#{'_=0;'*0x40000}
end
RUBY
set_local_a_lot
```
For low `--yjit-exec-mem-size` values, one basic block could exhaust the
entire buffer.
Introduce a new field `codeblock_t::dropped_bytes` that the assembler
sets whenever it runs out of space. Check this field in
gen_single_block() to respond to out of memory situations and other
error conditions. This design avoids making the control flow graph of
existing code generation functions more complex.
Use POSIX shell in misc/test_yjit_asm.sh since bash is expanding
`0%/*/*` differently.
Co-authored-by: Aaron Patterson <tenderlove@ruby-lang.org>
Some platforms don't want memory to be marked as writeable and
executable at the same time. When we write to the code block, we
calculate the OS page that the buffer position maps to. Then we call
`mprotect` to allow writes on that particular page. As an optimization,
we cache the "last written" aligned page which allows us to amortize the
cost of the `mprotect` call. In other words, sequential writes to the
same page will only call `mprotect` on the page once.
When we're done writing, we call `mprotect` on the entire JIT buffer.
This means we don't need to keep track of which pages were marked as
writeable, we let the OS take care of that.
Co-authored-by: John Hawthorn <john@hawthorn.email>
* YJIT: use shorter encoding for mov(r64,imm) when unambiguous
Previously, for small constants such as `mov(RAX, imm_opnd(Qundef))`,
we emit an instruction with an 8-byte immediate. This form commonly
gets the `movabs` mnemonic.
In 64-bit mode, 32-bit operands get zero extended to 64-bit to fill the
register, so when the immediate is small enough, we can save 4 bytes by
using the `mov` variant that takes a 32-bit immediate and does a zero
extension.
Not implement with this change, there is an imm32 variant of `mov` that
does sign extension we could use. When the constant is negative, we
fallback to the `movabs` form.
In railsbench, this change yields roughly a 12% code size reduction for
the outlined block.
Co-authored-by: Jemma Issroff <jemmaissroff@gmail.com>
* [ci skip] comment edit. Please squash.
Co-authored-by: Jemma Issroff <jemmaissroff@gmail.com>
* New code page allocation logic
* Fix leaked globals
* Fix leaked symbols, yjit asm tests
* Make COUNTED_EXIT take a jit argument, so we can eliminate global ocb
* Remove extra whitespace
* Change block start_pos/end_pos to be pointers instead of uint32_t
* Change branch end_pos and start_pos to end_addr, start_addr
On non RUBY_DEBUG builds, assert() compiles to nothing and the compiler
warns about uninitialized variables in those code paths. Replace
those asserts with rb_bug() to fix the warnings and do the assert in
all builds. Since yjit_asm_tests.c compiles outside of Ruby, it needed
a distinct version of rb_bug().
Also put YJIT_STATS check for function delcaration that is only defined
in YJIT_STATS builds.
This script is an lldb helper that just loops through all the comments
stored and prints out the comment along with the address corresponding
to the comment.
For example, I'm crashing in JIT code at address 0x0000000110000168.
Using the `lc` helper I can see that it's probably crashing inside the
exit back to the interpreter
```
(lldb) bt 5
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x22220021)
frame #0: 0x0000000110000168
* frame #1: 0x00000001002b5ff5 miniruby`invoke_block_from_c_bh [inlined] invoke_block(ec=0x0000000100e05350, iseq=0x0000000100c1ff10, self=0x0000000100c76cc0, captured=<unavailable>, cref=0x0000000000000000, type=<unavailable>, opt_pc=<unavailable>) at vm.c:1268:12
frame #2: 0x00000001002b5f7d miniruby`invoke_block_from_c_bh [inlined] invoke_iseq_block_from_c(ec=<unavailable>, captured=<unavailable>, self=0x0000000100c76cc0, argc=2, argv=<unavailable>, kw_splat=0, passed_block_handler=0x0000000000000000, cref=0x0000000000000000, is_lambda=<unavailable>, me=0x0000000000000000) at vm.c:1340
frame #3: 0x00000001002b5e14 miniruby`invoke_block_from_c_bh(ec=<unavailable>, block_handler=<unavailable>, argc=<unavailable>, argv=<unavailable>, kw_splat=0, passed_block_handler=0x0000000000000000, cref=0x0000000000000000, is_lambda=<unavailable>, force_blockarg=0) at vm.c:1358
frame #4: 0x000000010029860b miniruby`rb_yield_values(n=<unavailable>) at vm_eval.c:0
(lldb) lc
0x11000006d "putobject_INT2FIX_1_"
0x110000083 "leave"
0x110000087 "check for interrupts"
0x110000087 "RUBY_VM_CHECK_INTS(ec)"
0x110000098 "check for finish frame"
0x1100000ed "getlocal_WC_0"
0x110000107 "getlocal_WC_1"
0x11000012a "opt_send_without_block"
0x110000139 "opt_send_without_block"
0x11000013c "exit to interpreter"
```
This commits implements size classes in the GC for the Variable Width
Allocation feature. Unless `USE_RVARGC` compile flag is set, only a
single size class is created, maintaining current behaviour. See the
redmine ticket for more details.
Co-authored-by: Aaron Patterson <tenderlove@ruby-lang.org>
This commit removes T_PAYLOAD since the new VWA implementation no longer
requires T_PAYLOAD types.
Co-authored-by: Aaron Patterson <tenderlove@ruby-lang.org>
This commits implements size classes in the GC for the Variable Width
Allocation feature. Unless `USE_RVARGC` compile flag is set, only a
single size class is created, maintaining current behaviour. See the
redmine ticket for more details.
Co-authored-by: Aaron Patterson <tenderlove@ruby-lang.org>
This commit removes T_PAYLOAD since the new VWA implementation no longer
requires T_PAYLOAD types.
Co-authored-by: Aaron Patterson <tenderlove@ruby-lang.org>
rather than having to do this in a two step process:
1. heap_page obj
2. dump_page $2 (or whatever lldb variable heap_page set)
we can now just
dump_page_rvalue obj
Jemma Issroff
Matt Valentine-House
Nobuyoshi Nakada
Peter Zhu
Alan Wu
Aaron Patterson
Maxime Chevalier-Boisvert
Hiroshi SHIBATA
Alexander Popov
Martin Rey