diff options
| author | Richard Henderson <richard.henderson@linaro.org> | 2019-04-15 22:06:39 -1000 |
|---|---|---|
| committer | Richard Henderson <richard.henderson@linaro.org> | 2019-04-24 13:04:33 -0700 |
| commit | 6e6c4efed995d9eca6ae0cfdb2252df830262f50 (patch) | |
| tree | 89c518ebe67031eded9b892e7a2fad26286c736a /accel | |
| parent | 8b86d6d25807e13a63ab6ea879f976b9f18cc45a (diff) | |
tcg: Restart after TB code generation overflow
If a TB generates too much code, try again with fewer insns.
Fixes: https://bugs.launchpad.net/bugs/1824853
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'accel')
| -rw-r--r-- | accel/tcg/translate-all.c | 38 |
1 files changed, 32 insertions, 6 deletions
diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c index 39532fd44c..20b59f93f4 100644 --- a/accel/tcg/translate-all.c +++ b/accel/tcg/translate-all.c @@ -1722,6 +1722,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu, tb->cflags = cflags; tb->trace_vcpu_dstate = *cpu->trace_dstate; tcg_ctx->tb_cflags = cflags; + tb_overflow: #ifdef CONFIG_PROFILER /* includes aborted translations because of exceptions */ @@ -1755,14 +1756,39 @@ TranslationBlock *tb_gen_code(CPUState *cpu, ti = 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(tb, (void *)gen_code_buf + gen_code_size); if (unlikely(search_size < 0)) { |