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fix(library/vm/vm): prevent segfault

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This commit is contained in:
Gabriel Ebner 2017-05-18 15:21:11 +02:00 • committed by Leonardo de Moura
parent d9f5e0bb1f
commit 7353a54aac
1 changed files with 11 additions and 7 deletions
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18
src/library/vm/vm.cpp
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@ -1504,6 +1504,7 @@ void vm_state::invoke_fn(vm_cfunction fn, unsigned arity) {
flet<vm_state *> Set(g_vm_state, this);
auto & S = m_stack;
unsigned sz = S.size();
lean_vm_check(arity <= sz);
vm_obj r;
/* Important The stack m_stack may be resized during the execution of the function d.get_cfn().
Thus, to make sure the arguments are not garbage collected, we copy them into local variables a1 ... an.
@ -2826,7 +2827,7 @@ void vm_state::run() {
m_stack.push_back(m_stack[m_bp + instr.get_idx()]);
m_pc++;
goto main_loop;
case opcode::Move:
case opcode::Move: {
/* Instruction: move i
stack before, after
@ -2838,16 +2839,17 @@ void vm_state::run() {
v v
a_i
*/
unsigned off = m_bp + instr.get_idx();
lean_vm_check(off < m_stack.size());
if (LEAN_UNLIKELY(m_debugging)) {
m_stack.push_back(m_stack[m_bp + instr.get_idx()]);
m_pc++;
goto main_loop;
m_stack.push_back(m_stack[off]);
} else {
m_stack.push_back(mk_vm_unit());
swap(m_stack.back(), m_stack[m_bp + instr.get_idx()]);
m_pc++;
goto main_loop;
swap(m_stack.back(), m_stack[off]);
}
m_pc++;
goto main_loop;
}
case opcode::Drop: {
/* Instruction: drop n
@ -2898,6 +2900,7 @@ void vm_state::run() {
*/
unsigned nfields = instr.get_nfields();
unsigned sz = m_stack.size();
lean_vm_check(nfields <= sz);
vm_obj new_value = mk_vm_constructor(instr.get_cidx(), nfields, m_stack.data() + sz - nfields);
m_stack.resize(sz - nfields + 1);
swap(m_stack.back(), new_value);
@ -2917,6 +2920,7 @@ void vm_state::run() {
*/
unsigned nargs = instr.get_nargs();
unsigned sz = m_stack.size();
lean_vm_check(nargs <= sz);
vm_obj new_value = mk_vm_closure(instr.get_fn_idx(), nargs, m_stack.data() + sz - nargs);
m_stack.resize(sz - nargs + 1);
swap(m_stack.back(), new_value);