From 56b4935896ac3b34a515016027c495c4987fce11 Mon Sep 17 00:00:00 2001 From: notaz Date: Mon, 21 Sep 2015 00:29:34 +0300 Subject: [PATCH] translate: handle more noreturn cases --- tests/Makefile | 2 +- tests/reg_call_tail2.asm | 17 ++++++++ tests/reg_call_tail2.expect.c | 12 ++++++ tests/reg_call_tail2.seed.h | 1 + tools/translate.c | 76 ++++++++++++++++++++++++++--------- 5 files changed, 88 insertions(+), 20 deletions(-) create mode 100644 tests/reg_call_tail2.asm create mode 100644 tests/reg_call_tail2.expect.c create mode 100644 tests/reg_call_tail2.seed.h diff --git a/tests/Makefile b/tests/Makefile index 9f0639c..e49a7e4 100644 --- a/tests/Makefile +++ b/tests/Makefile @@ -1,6 +1,6 @@ TESTS = reg_call1 reg_call2 reg_call3 reg_call4 reg_call5 \ - reg_call_tail reg_save \ + reg_call_tail reg_call_tail2 reg_save \ varargs ops x87 x87_f x87_s deref all: $(addsuffix .ok,$(TESTS)) diff --git a/tests/reg_call_tail2.asm b/tests/reg_call_tail2.asm new file mode 100644 index 0000000..6562e23 --- /dev/null +++ b/tests/reg_call_tail2.asm @@ -0,0 +1,17 @@ + +_text segment para public 'CODE' use32 + +sub_test proc near + +arg_0 = dword ptr 4 + + inc [esp+arg_0] + jz return_ + jmp another_func +return_: + retn 4 +sub_test endp + +_text ends + +; vim:expandtab diff --git a/tests/reg_call_tail2.expect.c b/tests/reg_call_tail2.expect.c new file mode 100644 index 0000000..387f2e3 --- /dev/null +++ b/tests/reg_call_tail2.expect.c @@ -0,0 +1,12 @@ +void __stdcall sub_test(int a1) +{ + a1 += 1; // arg_0 + if ((u32)a1 == 0) + goto return_; // arg_0 + another_func(a1); + return; // ^ tailcall argframe + +return_: + return; +} + diff --git a/tests/reg_call_tail2.seed.h b/tests/reg_call_tail2.seed.h new file mode 100644 index 0000000..56dd159 --- /dev/null +++ b/tests/reg_call_tail2.seed.h @@ -0,0 +1 @@ +void __stdcall another_func(int a1); diff --git a/tools/translate.c b/tools/translate.c index 324bc26..2587d06 100644 --- a/tools/translate.c +++ b/tools/translate.c @@ -2694,8 +2694,9 @@ static int scan_for_rsave_pop_reg(int i, int magic, int reg, int set_flags) return -1; } - // nothing interesting on this path - return 0; + // nothing interesting on this path, + // still return ret for something recursive calls could find + return ret; } static void find_reachable_exits(int i, int opcnt, int magic, @@ -2746,7 +2747,8 @@ static int scan_for_pop_ret(int i, int opcnt, int reg, int set_flags) { static int exits[MAX_EXITS]; static int exit_count; - int j, ret; + int found = 0; + int e, j, ret; if (!set_flags) { exit_count = 0; @@ -2756,13 +2758,23 @@ static int scan_for_pop_ret(int i, int opcnt, int reg, int set_flags) } for (j = 0; j < exit_count; j++) { - ret = scan_for_rsave_pop_reg(exits[j], i + opcnt * 16 + set_flags, + e = exits[j]; + ret = scan_for_rsave_pop_reg(e, i + opcnt * 16 + set_flags, reg, set_flags); - if (ret == -1) - return -1; + if (ret != -1) { + found |= ret; + continue; + } + if (ops[e].op == OP_CALL && ops[e].pp != NULL + && ops[e].pp->is_noreturn) + { + // assume stack cleanup was skipped + continue; + } + return -1; } - return 1; + return found; } // scan for one or more pop of push @@ -3684,6 +3696,7 @@ static void resolve_branches_parse_calls(int opcnt) struct parsed_data *pd; struct parsed_op *po; const char *tmpname; + enum op_op prev_op; int i, l; int ret; @@ -3747,8 +3760,10 @@ static void resolve_branches_parse_calls(int opcnt) if (pp != NULL) { if (pp->is_fptr) check_func_pp(po, pp, "fptr var call"); - if (pp->is_noreturn) + if (pp->is_noreturn) { po->flags |= OPF_TAIL; + po->flags &= ~OPF_ATAIL; // most likely... + } } po->pp = pp; continue; @@ -3793,8 +3808,14 @@ static void resolve_branches_parse_calls(int opcnt) tailcall: po->op = OP_CALL; po->flags |= OPF_TAIL; - if (i > 0 && ops[i - 1].op == OP_POP) + prev_op = i > 0 ? ops[i - 1].op : OP_UD2; + if (prev_op == OP_POP) + po->flags |= OPF_ATAIL; + if (g_stack_fsz + g_bp_frame == 0 && prev_op != OP_PUSH + && (g_func_pp == NULL || g_func_pp->argc_stack > 0)) + { po->flags |= OPF_ATAIL; + } i--; // reprocess } } @@ -4022,13 +4043,22 @@ static void scan_prologue_epilogue(int opcnt) l += ops[j].operand[1].val / 4 - 1; } else - ferr(&ops[j], "'pop ecx' expected\n"); + break; ops[j].flags |= OPF_RMD | OPF_DONE | OPF_NOREGS; j--; } - if (l != ecx_push) + if (l != ecx_push) { + if (i < opcnt && ops[i].op == OP_CALL + && ops[i].pp != NULL && ops[i].pp->is_noreturn) + { + // noreturn tailcall with no epilogue + i++; + found = 1; + continue; + } ferr(&ops[j], "epilogue scan failed\n"); + } found = 1; } @@ -4039,11 +4069,12 @@ static void scan_prologue_epilogue(int opcnt) || ops[j].operand[1].type != OPT_CONST || ops[j].operand[1].val != g_stack_fsz) { - if (ops[i].op == OP_CALL && ops[i].pp != NULL - && ops[i].pp->is_noreturn) + if (i < opcnt && ops[i].op == OP_CALL + && ops[i].pp != NULL && ops[i].pp->is_noreturn) { // noreturn tailcall with no epilogue i++; + found = 1; continue; } ferr(&ops[j], "'add esp' expected\n"); @@ -4642,6 +4673,9 @@ static struct parsed_proto *process_call(int i, int opcnt) ferr(po, "too many args for '%s'\n", tmpname); } if (pp->argc_stack > adj / 4) { + if (pp->is_noreturn) + // assume no stack adjust was emited + goto out; fnote(po, "(this call)\n"); ferr(&ops[ret], "stack tracking failed for '%s': %x %x\n", tmpname, pp->argc_stack * 4, adj); @@ -4654,6 +4688,7 @@ static struct parsed_proto *process_call(int i, int opcnt) ferr(po, "missing esp_adjust for vararg func '%s'\n", pp->name); +out: return pp; } @@ -4904,8 +4939,8 @@ static int collect_call_args_r(struct parsed_op *po, int i, pp_tmp = ops[j].pp; if (pp_tmp == NULL) - ferr(po, "arg collect hit unparsed call '%s'\n", - ops[j].operand[0].name); + ferr(po, "arg collect %d/%d hit unparsed call '%s'\n", + arg, pp->argc, ops[j].operand[0].name); if (may_reuse && pp_tmp->argc_stack > 0) ferr(po, "arg collect %d/%d hit '%s' with %d stack args\n", arg, pp->argc, opr_name(&ops[j], 0), pp_tmp->argc_stack); @@ -6920,10 +6955,13 @@ static void gen_func(FILE *fout, FILE *fhdr, const char *funcn, int opcnt) pp->has_structarg ? "_sa" : ""); if (po->flags & OPF_ATAIL) { - if (pp->argc_stack != g_func_pp->argc_stack - || (pp->argc_stack > 0 - && pp->is_stdcall != g_func_pp->is_stdcall)) - ferr(po, "incompatible tailcall\n"); + int check_compat = + g_func_pp->is_stdcall && g_func_pp->argc_stack > 0; + check_compat |= pp->argc_stack > 0; + if (check_compat + && (pp->argc_stack != g_func_pp->argc_stack + || pp->is_stdcall != g_func_pp->is_stdcall)) + ferr(po, "incompatible arg-reuse tailcall\n"); if (g_func_pp->has_retreg) ferr(po, "TODO: retreg+tailcall\n"); -- 2.39.5