From 9f754620651d3432114f4bb89c7f12cbea814b3e Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Thu, 14 Jun 2018 19:57:03 -1000 Subject: tcg: Reduce max TB opcode count MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Also, assert that we don't overflow any of two different offsets into the TB. Both unwind and goto_tb both record a uint16_t for later use. This fixes an arm-softmmu test case utilizing NEON in which there is a TB generated that runs to 7800 opcodes, and compiles to 96k on an x86_64 host. This overflows the 16-bit offset in which we record the goto_tb reset offset. Because of that overflow, we install a jump destination that goes to neverland. Boom. With this reduced op count, the same TB compiles to about 48k for aarch64, ppc64le, and x86_64 hosts, and neither assertion fires. Cc: qemu-stable@nongnu.org Reported-by: "Jason A. Donenfeld" Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Richard Henderson --- tcg/aarch64/tcg-target.inc.c | 2 +- tcg/arm/tcg-target.inc.c | 2 +- tcg/i386/tcg-target.inc.c | 2 +- tcg/mips/tcg-target.inc.c | 2 +- tcg/ppc/tcg-target.inc.c | 4 ++-- tcg/s390/tcg-target.inc.c | 2 +- tcg/sparc/tcg-target.inc.c | 4 ++-- tcg/tcg.c | 13 ++++++++++++- tcg/tcg.h | 6 ++++-- tcg/tci/tcg-target.inc.c | 2 +- 10 files changed, 26 insertions(+), 13 deletions(-) (limited to 'tcg') diff --git a/tcg/aarch64/tcg-target.inc.c b/tcg/aarch64/tcg-target.inc.c index be31920..4562d36 100644 --- a/tcg/aarch64/tcg-target.inc.c +++ b/tcg/aarch64/tcg-target.inc.c @@ -1733,7 +1733,7 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc, tcg_out_insn(s, 3305, LDR, offset, TCG_REG_TMP); } tcg_out_insn(s, 3207, BR, TCG_REG_TMP); - s->tb_jmp_reset_offset[a0] = tcg_current_code_size(s); + set_jmp_reset_offset(s, a0); break; case INDEX_op_goto_ptr: diff --git a/tcg/arm/tcg-target.inc.c b/tcg/arm/tcg-target.inc.c index 56a32a4..e1fbf46 100644 --- a/tcg/arm/tcg-target.inc.c +++ b/tcg/arm/tcg-target.inc.c @@ -1822,7 +1822,7 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode opc, tcg_out_movi32(s, COND_AL, base, ptr - dil); } tcg_out_ld32_12(s, COND_AL, TCG_REG_PC, base, dil); - s->tb_jmp_reset_offset[args[0]] = tcg_current_code_size(s); + set_jmp_reset_offset(s, args[0]); } break; case INDEX_op_goto_ptr: diff --git a/tcg/i386/tcg-target.inc.c b/tcg/i386/tcg-target.inc.c index 0d0ff52..e87b0d4 100644 --- a/tcg/i386/tcg-target.inc.c +++ b/tcg/i386/tcg-target.inc.c @@ -2245,7 +2245,7 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode opc, tcg_out_modrm_offset(s, OPC_GRP5, EXT5_JMPN_Ev, -1, (intptr_t)(s->tb_jmp_target_addr + a0)); } - s->tb_jmp_reset_offset[a0] = tcg_current_code_size(s); + set_jmp_reset_offset(s, a0); break; case INDEX_op_goto_ptr: /* jmp to the given host address (could be epilogue) */ diff --git a/tcg/mips/tcg-target.inc.c b/tcg/mips/tcg-target.inc.c index ca5f1d4..cff5253 100644 --- a/tcg/mips/tcg-target.inc.c +++ b/tcg/mips/tcg-target.inc.c @@ -1744,7 +1744,7 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode opc, tcg_out_opc_reg(s, OPC_JR, 0, TCG_TMP0, 0); } tcg_out_nop(s); - s->tb_jmp_reset_offset[a0] = tcg_current_code_size(s); + set_jmp_reset_offset(s, a0); break; case INDEX_op_goto_ptr: /* jmp to the given host address (could be epilogue) */ diff --git a/tcg/ppc/tcg-target.inc.c b/tcg/ppc/tcg-target.inc.c index 86f7de5..c2f729e 100644 --- a/tcg/ppc/tcg-target.inc.c +++ b/tcg/ppc/tcg-target.inc.c @@ -2025,10 +2025,10 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc, const TCGArg *args, } tcg_out32(s, MTSPR | RS(TCG_REG_TB) | CTR); tcg_out32(s, BCCTR | BO_ALWAYS); - s->tb_jmp_reset_offset[args[0]] = c = tcg_current_code_size(s); + set_jmp_reset_offset(s, args[0]); if (USE_REG_TB) { /* For the unlinked case, need to reset TCG_REG_TB. */ - c = -c; + c = -tcg_current_code_size(s); assert(c == (int16_t)c); tcg_out32(s, ADDI | TAI(TCG_REG_TB, TCG_REG_TB, c)); } diff --git a/tcg/s390/tcg-target.inc.c b/tcg/s390/tcg-target.inc.c index 9af6dce..17c435a 100644 --- a/tcg/s390/tcg-target.inc.c +++ b/tcg/s390/tcg-target.inc.c @@ -1783,7 +1783,7 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode opc, /* and go there */ tcg_out_insn(s, RR, BCR, S390_CC_ALWAYS, TCG_REG_TB); } - s->tb_jmp_reset_offset[a0] = tcg_current_code_size(s); + set_jmp_reset_offset(s, a0); /* For the unlinked path of goto_tb, we need to reset TCG_REG_TB to the beginning of this TB. */ diff --git a/tcg/sparc/tcg-target.inc.c b/tcg/sparc/tcg-target.inc.c index bc673bd..04bdc3d 100644 --- a/tcg/sparc/tcg-target.inc.c +++ b/tcg/sparc/tcg-target.inc.c @@ -1388,12 +1388,12 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc, tcg_out_arithi(s, TCG_REG_G0, TCG_REG_TB, 0, JMPL); tcg_out_nop(s); } - s->tb_jmp_reset_offset[a0] = c = tcg_current_code_size(s); + set_jmp_reset_offset(s, a0); /* For the unlinked path of goto_tb, we need to reset TCG_REG_TB to the beginning of this TB. */ if (USE_REG_TB) { - c = -c; + c = -tcg_current_code_size(s); if (check_fit_i32(c, 13)) { tcg_out_arithi(s, TCG_REG_TB, TCG_REG_TB, c, ARITH_ADD); } else { diff --git a/tcg/tcg.c b/tcg/tcg.c index 1d1dfd7..f27b22b 100644 --- a/tcg/tcg.c +++ b/tcg/tcg.c @@ -306,6 +306,14 @@ TCGLabel *gen_new_label(void) return l; } +static void set_jmp_reset_offset(TCGContext *s, int which) +{ + size_t off = tcg_current_code_size(s); + s->tb_jmp_reset_offset[which] = off; + /* Make sure that we didn't overflow the stored offset. */ + assert(s->tb_jmp_reset_offset[which] == off); +} + #include "tcg-target.inc.c" /* compare a pointer @ptr and a tb_tc @s */ @@ -3532,7 +3540,10 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb) break; case INDEX_op_insn_start: if (num_insns >= 0) { - s->gen_insn_end_off[num_insns] = tcg_current_code_size(s); + size_t off = tcg_current_code_size(s); + s->gen_insn_end_off[num_insns] = off; + /* Assert that we do not overflow our stored offset. */ + assert(s->gen_insn_end_off[num_insns] == off); } num_insns++; for (i = 0; i < TARGET_INSN_START_WORDS; ++i) { diff --git a/tcg/tcg.h b/tcg/tcg.h index 532d2a0..f9f1237 100644 --- a/tcg/tcg.h +++ b/tcg/tcg.h @@ -850,9 +850,11 @@ static inline bool tcg_op_buf_full(void) /* This is not a hard limit, it merely stops translation when * we have produced "enough" opcodes. We want to limit TB size * such that a RISC host can reasonably use a 16-bit signed - * branch within the TB. + * branch within the TB. We also need to be mindful of the + * 16-bit unsigned offsets, TranslationBlock.jmp_reset_offset[] + * and TCGContext.gen_insn_end_off[]. */ - return tcg_ctx->nb_ops >= 8000; + return tcg_ctx->nb_ops >= 4000; } /* pool based memory allocation */ diff --git a/tcg/tci/tcg-target.inc.c b/tcg/tci/tcg-target.inc.c index cc949be..62ed097 100644 --- a/tcg/tci/tcg-target.inc.c +++ b/tcg/tci/tcg-target.inc.c @@ -574,7 +574,7 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc, const TCGArg *args, /* Indirect jump method. */ TODO(); } - s->tb_jmp_reset_offset[args[0]] = tcg_current_code_size(s); + set_jmp_reset_offset(s, args[0]); break; case INDEX_op_br: tci_out_label(s, arg_label(args[0])); -- cgit v1.1