yuzu/unicorn
1
0
Fork 0
mirror of https://github.com/yuzu-emu/unicorn.git synced 2025-02-25 12:26:53 +00:00
Code Issues Packages Projects Releases Wiki Activity

tcg: Restart after TB code generation overflow

Browse source 
If a TB generates too much code, try again with fewer insns.

Fixes: https://bugs.launchpad.net/bugs/1824853

Backports commit 6e6c4efed995d9eca6ae0cfdb2252df830262f50 from qemu
This commit is contained in:
Richard Henderson 2019-04-30 09:52:55 -04:00 committed by Lioncash
parent bca82cde84
commit 434b3ab9ec
No known key found for this signature in database
GPG key ID: 4E3C3CC1031BA9C7
2 changed files with 36 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

38
qemu/accel/tcg/translate-all.c
View file

@ -1360,6 +1360,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
tb->cs_base = cs_base;
tb->flags = flags;
tb->cflags = cflags;
tb_overflow:
#ifdef CONFIG_PROFILER
tcg_ctx->tb_count1++; /* includes aborted translations because of
@ -1406,14 +1407,39 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
tcg_ctx->code_time -= profile_getclock();
#endif
/* ??? Overflow could be handled better here. In particular, we
don't need to re-do gen_intermediate_code, nor should we re-do
the tcg optimization currently hidden inside tcg_gen_code. All
that should be required is to flush the TBs, allocate a new TB,
re-initialize it per above, and re-do the actual code generation. */
gen_code_size = tcg_gen_code(tcg_ctx, tb);
if (unlikely(gen_code_size < 0)) {
goto buffer_overflow;
switch (gen_code_size) {
case -1:
/*
* Overflow of code_gen_buffer, or the current slice of it.
*
* TODO: We don't need to re-do gen_intermediate_code, nor
* should we re-do the tcg optimization currently hidden
* inside tcg_gen_code. All that should be required is to
* flush the TBs, allocate a new TB, re-initialize it per
* above, and re-do the actual code generation.
*/
goto buffer_overflow;
case -2:
/*
* The code generated for the TranslationBlock is too large.
* The maximum size allowed by the unwind info is 64k.
* There may be stricter constraints from relocations
* in the tcg backend.
*
* Try again with half as many insns as we attempted this time.
* If a single insn overflows, there's a bug somewhere...
*/
max_insns = tb->icount;
assert(max_insns > 1);
max_insns /= 2;
goto tb_overflow;
default:
g_assert_not_reached();
}
}
search_size = encode_search(tcg_ctx, tb, (unsigned char *)gen_code_buf + gen_code_size);
if (unlikely(search_size < 0)) {

4
qemu/tcg/tcg.c
View file

@ -3366,6 +3366,10 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb)
if (unlikely((void *)s->code_ptr > s->code_gen_highwater)) {
return -1;
}
/* Test for TB overflow, as seen by gen_insn_end_off. */
if (unlikely(tcg_current_code_size(s) > UINT16_MAX)) {
return -2;
}
}
tcg_debug_assert(num_insns >= 0);
s->gen_insn_end_off[num_insns] = tcg_current_code_size(s);