diff options
Diffstat (limited to 'tcg/tcg.c')
| -rw-r--r-- | tcg/tcg.c | 14 |
1 files changed, 11 insertions, 3 deletions
@@ -385,9 +385,10 @@ void tcg_prologue_init(TCGContext *s) total_size = s->code_gen_buffer_size - prologue_size; s->code_gen_buffer_size = total_size; - /* Compute a high-water mark, at which we voluntarily flush the - buffer and start over. */ - s->code_gen_buffer_max_size = total_size - TCG_MAX_OP_SIZE * OPC_BUF_SIZE; + /* Compute a high-water mark, at which we voluntarily flush the buffer + and start over. The size here is arbitrary, significantly larger + than we expect the code generation for any one opcode to require. */ + s->code_gen_highwater = s->code_gen_buffer + (total_size - 1024); tcg_register_jit(s->code_gen_buffer, total_size); @@ -2438,6 +2439,13 @@ int tcg_gen_code(TCGContext *s, tcg_insn_unit *gen_code_buf) #ifndef NDEBUG check_regs(s); #endif + /* Test for (pending) buffer overflow. The assumption is that any + one operation beginning below the high water mark cannot overrun + the buffer completely. Thus we can test for overflow after + generating code without having to check during generation. */ + if (unlikely(s->code_gen_ptr > s->code_gen_highwater)) { + return -1; + } } tcg_debug_assert(num_insns >= 0); s->gen_insn_end_off[num_insns] = tcg_current_code_size(s); |