419 lines
17 KiB
C++
419 lines
17 KiB
C++
|
#include "internal.hh"
|
||
|
|
|
||
|
|
using namespace std;
|
||
|
|
|
||
|
|
DWARFPP_BEGIN_NAMESPACE
|
||
|
|
|
||
|
|
expr_context no_expr_context;
|
||
|
|
|
||
|
|
expr::expr(const unit *cu,
|
||
|
|
section_offset offset, section_length len)
|
||
|
|
: cu(cu), offset(offset), len(len)
|
||
|
|
{
|
||
|
|
}
|
||
|
|
|
||
|
|
expr_result
|
||
|
|
expr::evaluate(expr_context *ctx) const
|
||
|
|
{
|
||
|
|
return evaluate(ctx, {});
|
||
|
|
}
|
||
|
|
|
||
|
|
expr_result
|
||
|
|
expr::evaluate(expr_context *ctx, taddr argument) const
|
||
|
|
{
|
||
|
|
return evaluate(ctx, {argument});
|
||
|
|
}
|
||
|
|
|
||
|
|
expr_result
|
||
|
|
expr::evaluate(expr_context *ctx, const std::initializer_list<taddr> &arguments) const
|
||
|
|
{
|
||
|
|
// The stack machine's stack. The top of the stack is
|
||
|
|
// stack.back().
|
||
|
|
// XXX This stack must be in target machine representation,
|
||
|
|
// since I see both (DW_OP_breg0 (eax): -28; DW_OP_stack_value)
|
||
|
|
// and (DW_OP_lit1; DW_OP_stack_value).
|
||
|
|
small_vector<taddr, 8> stack;
|
||
|
|
|
||
|
|
// Create the initial stack. arguments are in reverse order
|
||
|
|
// (that is, element 0 is TOS), so reverse it.
|
||
|
|
stack.reserve(arguments.size());
|
||
|
|
for (const taddr *elt = arguments.end() - 1;
|
||
|
|
elt >= arguments.begin(); elt--)
|
||
|
|
stack.push_back(*elt);
|
||
|
|
|
||
|
|
// Create a subsection for just this expression so we can
|
||
|
|
// easily detect the end (including premature end).
|
||
|
|
auto cusec = cu->data();
|
||
|
|
shared_ptr<section> subsec
|
||
|
|
(make_shared<section>(cusec->type,
|
||
|
|
cusec->begin + offset, len,
|
||
|
|
cusec->fmt, cusec->addr_size));
|
||
|
|
cursor cur(subsec);
|
||
|
|
|
||
|
|
// Prepare the expression result. Some location descriptions
|
||
|
|
// create the result directly, rather than using the top of
|
||
|
|
// stack.
|
||
|
|
expr_result result;
|
||
|
|
|
||
|
|
// 2.6.1.1.4 Empty location descriptions
|
||
|
|
if (cur.end()) {
|
||
|
|
result.location_type = expr_result::type::empty;
|
||
|
|
result.value = 0;
|
||
|
|
return result;
|
||
|
|
}
|
||
|
|
|
||
|
|
// Assume the result is an address for now and should be
|
||
|
|
// grabbed from the top of stack at the end.
|
||
|
|
result.location_type = expr_result::type::address;
|
||
|
|
|
||
|
|
// Execute!
|
||
|
|
while (!cur.end()) {
|
||
|
|
#define CHECK() do { if (stack.empty()) goto underflow; } while (0)
|
||
|
|
#define CHECKN(n) do { if (stack.size() < n) goto underflow; } while (0)
|
||
|
|
union
|
||
|
|
{
|
||
|
|
uint64_t u;
|
||
|
|
int64_t s;
|
||
|
|
} tmp1, tmp2, tmp3;
|
||
|
|
static_assert(sizeof(tmp1) == sizeof(taddr), "taddr is not 64 bits");
|
||
|
|
|
||
|
|
// Tell GCC to warn us about missing switch cases,
|
||
|
|
// even though we have a default case.
|
||
|
|
#pragma GCC diagnostic push
|
||
|
|
#pragma GCC diagnostic warning "-Wswitch-enum"
|
||
|
|
DW_OP op = (DW_OP)cur.fixed<ubyte>();
|
||
|
|
switch (op) {
|
||
|
|
// 2.5.1.1 Literal encodings
|
||
|
|
case DW_OP::lit0...DW_OP::lit31:
|
||
|
|
stack.push_back((unsigned)op - (unsigned)DW_OP::lit0);
|
||
|
|
break;
|
||
|
|
case DW_OP::addr:
|
||
|
|
stack.push_back(cur.address());
|
||
|
|
break;
|
||
|
|
case DW_OP::const1u:
|
||
|
|
stack.push_back(cur.fixed<uint8_t>());
|
||
|
|
break;
|
||
|
|
case DW_OP::const2u:
|
||
|
|
stack.push_back(cur.fixed<uint16_t>());
|
||
|
|
break;
|
||
|
|
case DW_OP::const4u:
|
||
|
|
stack.push_back(cur.fixed<uint32_t>());
|
||
|
|
break;
|
||
|
|
case DW_OP::const8u:
|
||
|
|
stack.push_back(cur.fixed<uint64_t>());
|
||
|
|
break;
|
||
|
|
case DW_OP::const1s:
|
||
|
|
stack.push_back(cur.fixed<int8_t>());
|
||
|
|
break;
|
||
|
|
case DW_OP::const2s:
|
||
|
|
stack.push_back(cur.fixed<int16_t>());
|
||
|
|
break;
|
||
|
|
case DW_OP::const4s:
|
||
|
|
stack.push_back(cur.fixed<int32_t>());
|
||
|
|
break;
|
||
|
|
case DW_OP::const8s:
|
||
|
|
stack.push_back(cur.fixed<int64_t>());
|
||
|
|
break;
|
||
|
|
case DW_OP::constu:
|
||
|
|
stack.push_back(cur.uleb128());
|
||
|
|
break;
|
||
|
|
case DW_OP::consts:
|
||
|
|
stack.push_back(cur.sleb128());
|
||
|
|
break;
|
||
|
|
|
||
|
|
// 2.5.1.2 Register based addressing
|
||
|
|
case DW_OP::fbreg:
|
||
|
|
// XXX
|
||
|
|
throw runtime_error("DW_OP_fbreg not implemented");
|
||
|
|
case DW_OP::breg0...DW_OP::breg31:
|
||
|
|
tmp1.u = (unsigned)op - (unsigned)DW_OP::breg0;
|
||
|
|
tmp2.s = cur.sleb128();
|
||
|
|
stack.push_back((int64_t)ctx->reg(tmp1.u) + tmp2.s);
|
||
|
|
break;
|
||
|
|
case DW_OP::bregx:
|
||
|
|
tmp1.u = cur.uleb128();
|
||
|
|
tmp2.s = cur.sleb128();
|
||
|
|
stack.push_back((int64_t)ctx->reg(tmp1.u) + tmp2.s);
|
||
|
|
break;
|
||
|
|
|
||
|
|
// 2.5.1.3 Stack operations
|
||
|
|
case DW_OP::dup:
|
||
|
|
CHECK();
|
||
|
|
stack.push_back(stack.back());
|
||
|
|
break;
|
||
|
|
case DW_OP::drop:
|
||
|
|
CHECK();
|
||
|
|
stack.pop_back();
|
||
|
|
break;
|
||
|
|
case DW_OP::pick:
|
||
|
|
tmp1.u = cur.fixed<uint8_t>();
|
||
|
|
CHECKN(tmp1.u);
|
||
|
|
stack.push_back(stack.revat(tmp1.u));
|
||
|
|
break;
|
||
|
|
case DW_OP::over:
|
||
|
|
CHECKN(2);
|
||
|
|
stack.push_back(stack.revat(1));
|
||
|
|
break;
|
||
|
|
case DW_OP::swap:
|
||
|
|
CHECKN(2);
|
||
|
|
tmp1.u = stack.back();
|
||
|
|
stack.back() = stack.revat(1);
|
||
|
|
stack.revat(1) = tmp1.u;
|
||
|
|
break;
|
||
|
|
case DW_OP::rot:
|
||
|
|
CHECKN(3);
|
||
|
|
tmp1.u = stack.back();
|
||
|
|
stack.back() = stack.revat(1);
|
||
|
|
stack.revat(1) = stack.revat(2);
|
||
|
|
stack.revat(2) = tmp1.u;
|
||
|
|
break;
|
||
|
|
case DW_OP::deref:
|
||
|
|
tmp1.u = subsec->addr_size;
|
||
|
|
goto deref_common;
|
||
|
|
case DW_OP::deref_size:
|
||
|
|
tmp1.u = cur.fixed<uint8_t>();
|
||
|
|
if (tmp1.u > subsec->addr_size)
|
||
|
|
throw expr_error("DW_OP_deref_size operand exceeds address size");
|
||
|
|
deref_common:
|
||
|
|
CHECK();
|
||
|
|
stack.back() = ctx->deref_size(stack.back(), tmp1.u);
|
||
|
|
break;
|
||
|
|
case DW_OP::xderef:
|
||
|
|
tmp1.u = subsec->addr_size;
|
||
|
|
goto xderef_common;
|
||
|
|
case DW_OP::xderef_size:
|
||
|
|
tmp1.u = cur.fixed<uint8_t>();
|
||
|
|
if (tmp1.u > subsec->addr_size)
|
||
|
|
throw expr_error("DW_OP_xderef_size operand exceeds address size");
|
||
|
|
xderef_common:
|
||
|
|
CHECKN(2);
|
||
|
|
tmp2.u = stack.back();
|
||
|
|
stack.pop_back();
|
||
|
|
stack.back() = ctx->xderef_size(tmp2.u, stack.back(), tmp1.u);
|
||
|
|
break;
|
||
|
|
case DW_OP::push_object_address:
|
||
|
|
// XXX
|
||
|
|
throw runtime_error("DW_OP_push_object_address not implemented");
|
||
|
|
case DW_OP::form_tls_address:
|
||
|
|
CHECK();
|
||
|
|
stack.back() = ctx->form_tls_address(stack.back());
|
||
|
|
break;
|
||
|
|
case DW_OP::call_frame_cfa:
|
||
|
|
// XXX
|
||
|
|
throw runtime_error("DW_OP_call_frame_cfa not implemented");
|
||
|
|
|
||
|
|
// 2.5.1.4 Arithmetic and logical operations
|
||
|
|
#define UBINOP(binop) \
|
||
|
|
do { \
|
||
|
|
CHECKN(2); \
|
||
|
|
tmp1.u = stack.back(); \
|
||
|
|
stack.pop_back(); \
|
||
|
|
tmp2.u = stack.back(); \
|
||
|
|
stack.back() = tmp2.u binop tmp1.u; \
|
||
|
|
} while (0)
|
||
|
|
case DW_OP::abs:
|
||
|
|
CHECK();
|
||
|
|
tmp1.u = stack.back();
|
||
|
|
if (tmp1.s < 0)
|
||
|
|
tmp1.s = -tmp1.s;
|
||
|
|
stack.back() = tmp1.u;
|
||
|
|
break;
|
||
|
|
case DW_OP::and_:
|
||
|
|
UBINOP(&);
|
||
|
|
break;
|
||
|
|
case DW_OP::div:
|
||
|
|
CHECKN(2);
|
||
|
|
tmp1.u = stack.back();
|
||
|
|
stack.pop_back();
|
||
|
|
tmp2.u = stack.back();
|
||
|
|
tmp3.s = tmp1.s / tmp2.s;
|
||
|
|
stack.back() = tmp3.u;
|
||
|
|
break;
|
||
|
|
case DW_OP::minus:
|
||
|
|
UBINOP(-);
|
||
|
|
break;
|
||
|
|
case DW_OP::mod:
|
||
|
|
UBINOP(%);
|
||
|
|
break;
|
||
|
|
case DW_OP::mul:
|
||
|
|
UBINOP(*);
|
||
|
|
break;
|
||
|
|
case DW_OP::neg:
|
||
|
|
CHECK();
|
||
|
|
tmp1.u = stack.back();
|
||
|
|
tmp1.s = -tmp1.s;
|
||
|
|
stack.back() = tmp1.u;
|
||
|
|
break;
|
||
|
|
case DW_OP::not_:
|
||
|
|
CHECK();
|
||
|
|
stack.back() = ~stack.back();
|
||
|
|
break;
|
||
|
|
case DW_OP::or_:
|
||
|
|
UBINOP(|);
|
||
|
|
break;
|
||
|
|
case DW_OP::plus:
|
||
|
|
UBINOP(+);
|
||
|
|
break;
|
||
|
|
case DW_OP::plus_uconst:
|
||
|
|
tmp1.u = cur.uleb128();
|
||
|
|
CHECK();
|
||
|
|
stack.back() += tmp1.u;
|
||
|
|
break;
|
||
|
|
case DW_OP::shl:
|
||
|
|
CHECKN(2);
|
||
|
|
tmp1.u = stack.back();
|
||
|
|
stack.pop_back();
|
||
|
|
tmp2.u = stack.back();
|
||
|
|
// C++ does not define what happens if you
|
||
|
|
// shift by more bits than the width of the
|
||
|
|
// type, so we handle this case specially
|
||
|
|
if (tmp1.u < sizeof(tmp2.u)*8)
|
||
|
|
stack.back() = tmp2.u << tmp1.u;
|
||
|
|
else
|
||
|
|
stack.back() = 0;
|
||
|
|
break;
|
||
|
|
case DW_OP::shr:
|
||
|
|
CHECKN(2);
|
||
|
|
tmp1.u = stack.back();
|
||
|
|
stack.pop_back();
|
||
|
|
tmp2.u = stack.back();
|
||
|
|
// Same as above
|
||
|
|
if (tmp1.u < sizeof(tmp2.u)*8)
|
||
|
|
stack.back() = tmp2.u >> tmp1.u;
|
||
|
|
else
|
||
|
|
stack.back() = 0;
|
||
|
|
break;
|
||
|
|
case DW_OP::shra:
|
||
|
|
CHECKN(2);
|
||
|
|
tmp1.u = stack.back();
|
||
|
|
stack.pop_back();
|
||
|
|
tmp2.u = stack.back();
|
||
|
|
// Shifting a negative number is
|
||
|
|
// implementation-defined in C++.
|
||
|
|
tmp3.u = (tmp2.s < 0);
|
||
|
|
if (tmp3.u)
|
||
|
|
tmp2.s = -tmp2.s;
|
||
|
|
if (tmp1.u < sizeof(tmp2.u)*8)
|
||
|
|
tmp2.u >>= tmp1.u;
|
||
|
|
else
|
||
|
|
tmp2.u = 0;
|
||
|
|
// DWARF implies that over-shifting a negative
|
||
|
|
// number should result in 0, not ~0.
|
||
|
|
if (tmp3.u)
|
||
|
|
tmp2.s = -tmp2.s;
|
||
|
|
stack.back() = tmp2.u;
|
||
|
|
break;
|
||
|
|
case DW_OP::xor_:
|
||
|
|
UBINOP(^);
|
||
|
|
break;
|
||
|
|
#undef UBINOP
|
||
|
|
|
||
|
|
// 2.5.1.5 Control flow operations
|
||
|
|
#define SRELOP(relop) \
|
||
|
|
do { \
|
||
|
|
CHECKN(2); \
|
||
|
|
tmp1.u = stack.back(); \
|
||
|
|
stack.pop_back(); \
|
||
|
|
tmp2.u = stack.back(); \
|
||
|
|
stack.back() = (tmp2.s <= tmp1.s) ? 1 : 0; \
|
||
|
|
} while (0)
|
||
|
|
case DW_OP::le:
|
||
|
|
SRELOP(<=);
|
||
|
|
break;
|
||
|
|
case DW_OP::ge:
|
||
|
|
SRELOP(>=);
|
||
|
|
break;
|
||
|
|
case DW_OP::eq:
|
||
|
|
SRELOP(==);
|
||
|
|
break;
|
||
|
|
case DW_OP::lt:
|
||
|
|
SRELOP(<);
|
||
|
|
break;
|
||
|
|
case DW_OP::gt:
|
||
|
|
SRELOP(>);
|
||
|
|
break;
|
||
|
|
case DW_OP::ne:
|
||
|
|
SRELOP(!=);
|
||
|
|
break;
|
||
|
|
case DW_OP::skip:
|
||
|
|
tmp1.s = cur.fixed<int16_t>();
|
||
|
|
goto skip_common;
|
||
|
|
case DW_OP::bra:
|
||
|
|
tmp1.s = cur.fixed<int16_t>();
|
||
|
|
CHECK();
|
||
|
|
tmp2.u = stack.back();
|
||
|
|
stack.pop_back();
|
||
|
|
if (tmp2.u == 0)
|
||
|
|
break;
|
||
|
|
skip_common:
|
||
|
|
cur = cursor(subsec, (int64_t)cur.get_section_offset() + tmp1.s);
|
||
|
|
break;
|
||
|
|
case DW_OP::call2:
|
||
|
|
case DW_OP::call4:
|
||
|
|
case DW_OP::call_ref:
|
||
|
|
// XXX
|
||
|
|
throw runtime_error(to_string(op) + " not implemented");
|
||
|
|
#undef SRELOP
|
||
|
|
|
||
|
|
// 2.5.1.6 Special operations
|
||
|
|
case DW_OP::nop:
|
||
|
|
break;
|
||
|
|
|
||
|
|
// 2.6.1.1.2 Register location descriptions
|
||
|
|
case DW_OP::reg0...DW_OP::reg31:
|
||
|
|
result.location_type = expr_result::type::reg;
|
||
|
|
result.value = (unsigned)op - (unsigned)DW_OP::reg0;
|
||
|
|
break;
|
||
|
|
case DW_OP::regx:
|
||
|
|
result.location_type = expr_result::type::reg;
|
||
|
|
result.value = cur.uleb128();
|
||
|
|
break;
|
||
|
|
|
||
|
|
// 2.6.1.1.3 Implicit location descriptions
|
||
|
|
case DW_OP::implicit_value:
|
||
|
|
result.location_type = expr_result::type::implicit;
|
||
|
|
result.implicit_len = cur.uleb128();
|
||
|
|
cur.ensure(result.implicit_len);
|
||
|
|
result.implicit = cur.pos;
|
||
|
|
break;
|
||
|
|
case DW_OP::stack_value:
|
||
|
|
CHECK();
|
||
|
|
result.location_type = expr_result::type::literal;
|
||
|
|
result.value = stack.back();
|
||
|
|
break;
|
||
|
|
|
||
|
|
// 2.6.1.2 Composite location descriptions
|
||
|
|
case DW_OP::piece:
|
||
|
|
case DW_OP::bit_piece:
|
||
|
|
// XXX
|
||
|
|
throw runtime_error(to_string(op) + " not implemented");
|
||
|
|
|
||
|
|
case DW_OP::lo_user...DW_OP::hi_user:
|
||
|
|
// XXX We could let the context evaluate this,
|
||
|
|
// but it would need access to the cursor.
|
||
|
|
throw expr_error("unknown user op " + to_string(op));
|
||
|
|
|
||
|
|
default:
|
||
|
|
throw expr_error("bad operation " + to_string(op));
|
||
|
|
}
|
||
|
|
#pragma GCC diagnostic pop
|
||
|
|
#undef CHECK
|
||
|
|
#undef CHECKN
|
||
|
|
}
|
||
|
|
|
||
|
|
if (result.location_type == expr_result::type::address) {
|
||
|
|
// The result type is still and address, so we should
|
||
|
|
// fetch it from the top of stack.
|
||
|
|
if (stack.empty())
|
||
|
|
throw expr_error("final stack is empty; no result given");
|
||
|
|
result.value = stack.back();
|
||
|
|
}
|
||
|
|
|
||
|
|
return result;
|
||
|
|
|
||
|
|
underflow:
|
||
|
|
throw expr_error("stack underflow evaluating DWARF expression");
|
||
|
|
}
|
||
|
|
|
||
|
|
DWARFPP_END_NAMESPACE
|