OSO/TinyCC
2
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

a bounds checking code for the ARCH=x86_64

Browse Source
This commit is contained in:
seyko
2015-04-10 15:17:22 +03:00
parent e92dc595cd
commit 559675b90a
8 changed files with 319 additions and 64 deletions
Download Patch File Download Diff File Expand all files Collapse all files

126
x86_64-gen.c
View File

@ -625,6 +625,90 @@ static void gcall_or_jmp(int is_jmp)
}
}
#if defined(CONFIG_TCC_BCHECK)
#ifndef TCC_TARGET_PE
static addr_t func_bound_offset;
static unsigned long func_bound_ind;
#endif
static void gen_static_call(int v)
{
Sym *sym = external_global_sym(v, &func_old_type, 0);
oad(0xe8, -4);
greloc(cur_text_section, sym, ind-4, R_X86_64_PC32);
}
/* generate a bounded pointer addition */
ST_FUNC void gen_bounded_ptr_add(void)
{
/* save all temporary registers */
save_regs(0);
/* prepare fast x86_64 function call */
gv(RC_RAX);
o(0xc68948); // mov %rax,%rsi ## second arg in %rsi, this must be size
vtop--;
gv(RC_RAX);
o(0xc78948); // mov %rax,%rdi ## first arg in %rdi, this must be ptr
vtop--;
/* do a fast function call */
gen_static_call(TOK___bound_ptr_add);
/* returned pointer is in rax */
vtop++;
vtop->r = TREG_RAX | VT_BOUNDED;
/* relocation offset of the bounding function call point */
vtop->c.ull = (cur_text_section->reloc->data_offset - sizeof(ElfW(Rela)));
}
/* patch pointer addition in vtop so that pointer dereferencing is
also tested */
ST_FUNC void gen_bounded_ptr_deref(void)
{
addr_t func;
int size, align;
ElfW(Rela) *rel;
Sym *sym;
size = 0;
/* XXX: put that code in generic part of tcc */
if (!is_float(vtop->type.t)) {
if (vtop->r & VT_LVAL_BYTE)
size = 1;
else if (vtop->r & VT_LVAL_SHORT)
size = 2;
}
if (!size)
size = type_size(&vtop->type, &align);
switch(size) {
case 1: func = TOK___bound_ptr_indir1; break;
case 2: func = TOK___bound_ptr_indir2; break;
case 4: func = TOK___bound_ptr_indir4; break;
case 8: func = TOK___bound_ptr_indir8; break;
case 12: func = TOK___bound_ptr_indir12; break;
case 16: func = TOK___bound_ptr_indir16; break;
default:
tcc_error("unhandled size when dereferencing bounded pointer");
func = 0;
break;
}
sym = external_global_sym(func, &func_old_type, 0);
if (!sym->c)
put_extern_sym(sym, NULL, 0, 0);
/* patch relocation */
/* XXX: find a better solution ? */
rel = (ElfW(Rela) *)(cur_text_section->reloc->data + vtop->c.ull);
rel->r_info = ELF64_R_INFO(sym->c, ELF64_R_TYPE(rel->r_info));
}
#endif
#ifdef TCC_TARGET_PE
#define REGN 4
@ -1520,6 +1604,17 @@ void gfunc_prolog(CType *func_type)
sym_push(sym->v & ~SYM_FIELD, type,
VT_LOCAL | VT_LVAL, param_addr);
}
#ifdef CONFIG_TCC_BCHECK
/* leave some room for bound checking code */
if (tcc_state->do_bounds_check) {
func_bound_offset = lbounds_section->data_offset;
func_bound_ind = ind;
oad(0xb8, 0); /* lbound section pointer */
o(0xc78948); /* mov %rax,%rdi ## first arg in %rdi, this must be ptr */
oad(0xb8, 0); /* call to function */
}
#endif
}
/* generate function epilog */
@ -1527,6 +1622,37 @@ void gfunc_epilog(void)
{
int v, saved_ind;
#ifdef CONFIG_TCC_BCHECK
if (tcc_state->do_bounds_check
&& func_bound_offset != lbounds_section->data_offset)
{
addr_t saved_ind;
addr_t *bounds_ptr;
Sym *sym_data;
/* add end of table info */
bounds_ptr = section_ptr_add(lbounds_section, sizeof(addr_t));
*bounds_ptr = 0;
/* generate bound local allocation */
sym_data = get_sym_ref(&char_pointer_type, lbounds_section,
func_bound_offset, lbounds_section->data_offset);
saved_ind = ind;
ind = func_bound_ind;
greloc(cur_text_section, sym_data, ind + 1, R_386_32);
ind = ind + 5 + 3;
gen_static_call(TOK___bound_local_new);
ind = saved_ind;
/* generate bound check local freeing */
o(0x5250); /* save returned value, if any */
greloc(cur_text_section, sym_data, ind + 1, R_386_32);
oad(0xb8, 0); /* mov xxx, %rax */
o(0xc78948); /* mov %rax,%rdi ## first arg in %rdi, this must be ptr */
gen_static_call(TOK___bound_local_delete);
o(0x585a); /* restore returned value, if any */
}
#endif
o(0xc9); /* leave */
if (func_ret_sub == 0) {
o(0xc3); /* ret */