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NetBSD/sys/lib/libunwind/DwarfInstructions.hpp

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//===-------------------------- DwarfInstructions.hpp ---------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//
// Processor specific interpretation of DWARF unwind info.
//
//===----------------------------------------------------------------------===//
#ifndef __DWARF_INSTRUCTIONS_HPP__
#define __DWARF_INSTRUCTIONS_HPP__
#include <cstdint>
#include <cstdlib>
#include "dwarf2.h"
#include "AddressSpace.hpp"
#include "Registers.hpp"
#include "DwarfParser.hpp"
namespace _Unwind {
enum step_result {
UNW_STEP_SUCCESS,
UNW_STEP_END,
UNW_STEP_FAILED
};
/// DwarfInstructions maps abtract dwarf unwind instructions to a particular
/// architecture
template <typename A, typename R> class DwarfInstructions {
public:
typedef typename A::pint_t pint_t;
typedef typename A::sint_t sint_t;
static step_result stepWithDwarf(A &, pint_t, pint_t, R &, unw_proc_info_t *);
private:
static pint_t evaluateExpression(pint_t, A &, const R &, pint_t);
static pint_t
getSavedRegister(A &, const R &, pint_t,
const typename CFI_Parser<A, R>::RegisterLocation &);
static pint_t
computeRegisterLocation(A &, const R &, pint_t,
const typename CFI_Parser<A, R>::RegisterLocation &);
static int lastRestoreReg(const R &) { return R::LAST_RESTORE_REG; }
static pint_t getCFA(A &addressSpace,
const typename CFI_Parser<A, R>::PrologInfo &prolog,
const R &registers) {
if (prolog.cfaRegister != 0)
return registers.getRegister(prolog.cfaRegister) +
prolog.cfaRegisterOffset;
if (prolog.cfaExpression != 0)
return evaluateExpression(prolog.cfaExpression, addressSpace, registers,
0);
assert(0 && "getCFA(): unknown location");
__builtin_unreachable();
}
};
template <typename A, typename R>
typename A::pint_t DwarfInstructions<A, R>::getSavedRegister(
A &addressSpace, const R &registers, pint_t cfa,
const typename CFI_Parser<A, R>::RegisterLocation &savedReg) {
switch (savedReg.location) {
case CFI_Parser<A, R>::kRegisterInCFA:
return addressSpace.getP(cfa + savedReg.value);
case CFI_Parser<A, R>::kRegisterAtExpression:
return addressSpace.getP(
evaluateExpression(savedReg.value, addressSpace, registers, cfa));
case CFI_Parser<A, R>::kRegisterIsExpression:
return evaluateExpression(savedReg.value, addressSpace, registers, cfa);
case CFI_Parser<A, R>::kRegisterInRegister:
return registers.getRegister(savedReg.value);
case CFI_Parser<A, R>::kRegisterUnused:
case CFI_Parser<A, R>::kRegisterOffsetFromCFA:
assert(0 && "unsupported restore location for register");
}
__builtin_unreachable();
}
template <typename A, typename R>
typename DwarfInstructions<A, R>::pint_t
DwarfInstructions<A, R>::computeRegisterLocation(
A &addressSpace, const R &registers, pint_t cfa,
const typename CFI_Parser<A, R>::RegisterLocation &savedReg) {
switch (savedReg.location) {
case CFI_Parser<A, R>::kRegisterInCFA:
return cfa + savedReg.value;
case CFI_Parser<A, R>::kRegisterAtExpression:
return evaluateExpression(savedReg.value, addressSpace, registers, cfa);
case CFI_Parser<A, R>::kRegisterIsExpression:
case CFI_Parser<A, R>::kRegisterUnused:
case CFI_Parser<A, R>::kRegisterOffsetFromCFA:
case CFI_Parser<A, R>::kRegisterInRegister:
assert(0 && "unsupported restore location for float/vector register");
}
__builtin_unreachable();
}
template <typename A, typename R>
step_result DwarfInstructions<A, R>::stepWithDwarf(A &addressSpace, pint_t pc,
pint_t fdeStart,
R &registers,
unw_proc_info_t *ctx) {
typename CFI_Parser<A, R>::FDE_Info fdeInfo;
typename CFI_Parser<A, R>::CIE_Info cieInfo;
if (!CFI_Parser<A, R>::decodeFDE(addressSpace, fdeStart, &fdeInfo, &cieInfo,
ctx))
return UNW_STEP_FAILED;
typename CFI_Parser<A, R>::PrologInfo prolog;
if (!CFI_Parser<A, R>::parseFDEInstructions(addressSpace, fdeInfo, cieInfo,
pc, &prolog, ctx))
return UNW_STEP_FAILED;
// Create working copy of the register set.
R newRegisters = registers;
// Get pointer to CFA by the architecture-specific code.
pint_t cfa = getCFA(addressSpace, prolog, registers);
// Restore registers according to DWARF instructions
pint_t returnAddress = 0;
for (int i = 0; i <= lastRestoreReg(newRegisters); ++i) {
if (prolog.savedRegisters[i].location == CFI_Parser<A, R>::kRegisterUnused)
continue;
if (i == (int)cieInfo.returnAddressRegister)
returnAddress = getSavedRegister(addressSpace, registers, cfa,
prolog.savedRegisters[i]);
else if (registers.validRegister(i))
newRegisters.setRegister(i, getSavedRegister(addressSpace, registers, cfa,
prolog.savedRegisters[i]));
else if (registers.validFloatVectorRegister(i))
newRegisters.copyFloatVectorRegister(
i, computeRegisterLocation(addressSpace, registers, cfa,
prolog.savedRegisters[i]));
else
return UNW_STEP_FAILED;
}
// The CFA is defined as the stack pointer at the call site.
// Therefore the SP is restored by setting it to the CFA.
newRegisters.setSP(cfa);
newRegisters.setIP(returnAddress + R::RETURN_OFFSET);
// Now replace register set with the working copy.
registers = newRegisters;
return UNW_STEP_SUCCESS;
}
template <typename A, typename R>
typename A::pint_t
DwarfInstructions<A, R>::evaluateExpression(pint_t expression, A &addressSpace,
const R &registers,
pint_t initialStackValue) {
pint_t p = expression;
pint_t expressionEnd = expression + 20; // Rough estimate
uint64_t length = addressSpace.getULEB128(p, expressionEnd);
expressionEnd = p + length;
pint_t stack[100];
pint_t *sp = stack;
*(++sp) = initialStackValue;
while (p < expressionEnd) {
uint8_t opcode = addressSpace.get8(p++);
sint_t svalue;
pint_t value;
uint32_t reg;
switch (opcode) {
case DW_OP_addr:
// push immediate address sized value
value = addressSpace.getP(p);
p += sizeof(pint_t);
*(++sp) = value;
break;
case DW_OP_deref:
// pop stack, dereference, push result
value = *sp--;
*(++sp) = addressSpace.getP(value);
break;
case DW_OP_const1u:
// push immediate 1 byte value
value = addressSpace.get8(p);
p += 1;
*(++sp) = value;
break;
case DW_OP_const1s:
// push immediate 1 byte signed value
svalue = (int8_t)addressSpace.get8(p);
p += 1;
*(++sp) = svalue;
break;
case DW_OP_const2u:
// push immediate 2 byte value
value = addressSpace.get16(p);
p += 2;
*(++sp) = value;
break;
case DW_OP_const2s:
// push immediate 2 byte signed value
svalue = (int16_t)addressSpace.get16(p);
p += 2;
*(++sp) = svalue;
break;
case DW_OP_const4u:
// push immediate 4 byte value
value = addressSpace.get32(p);
p += 4;
*(++sp) = value;
break;
case DW_OP_const4s:
// push immediate 4 byte signed value
svalue = (int32_t)addressSpace.get32(p);
p += 4;
*(++sp) = svalue;
break;
case DW_OP_const8u:
// push immediate 8 byte value
value = addressSpace.get64(p);
p += 8;
*(++sp) = value;
break;
case DW_OP_const8s:
// push immediate 8 byte signed value
value = (int32_t)addressSpace.get64(p);
p += 8;
*(++sp) = value;
break;
case DW_OP_constu:
// push immediate ULEB128 value
value = addressSpace.getULEB128(p, expressionEnd);
*(++sp) = value;
break;
case DW_OP_consts:
// push immediate SLEB128 value
svalue = addressSpace.getSLEB128(p, expressionEnd);
*(++sp) = svalue;
break;
case DW_OP_dup:
// push top of stack
value = *sp;
*(++sp) = value;
break;
case DW_OP_drop:
// pop
--sp;
break;
case DW_OP_over:
// dup second
value = sp[-1];
*(++sp) = value;
break;
case DW_OP_pick:
// pick from
reg = addressSpace.get8(p);
p += 1;
value = sp[-reg];
*(++sp) = value;
break;
case DW_OP_swap:
// swap top two
value = sp[0];
sp[0] = sp[-1];
sp[-1] = value;
break;
case DW_OP_rot:
// rotate top three
value = sp[0];
sp[0] = sp[-1];
sp[-1] = sp[-2];
sp[-2] = value;
break;
case DW_OP_xderef:
// pop stack, dereference, push result
value = *sp--;
*sp = *((uint64_t *)value);
break;
case DW_OP_abs:
svalue = *sp;
if (svalue < 0)
*sp = -svalue;
break;
case DW_OP_and:
value = *sp--;
*sp &= value;
break;
case DW_OP_div:
svalue = *sp--;
*sp = *sp / svalue;
break;
case DW_OP_minus:
svalue = *sp--;
*sp = *sp - svalue;
break;
case DW_OP_mod:
svalue = *sp--;
*sp = *sp % svalue;
break;
case DW_OP_mul:
svalue = *sp--;
*sp = *sp * svalue;
break;
case DW_OP_neg:
*sp = 0 - *sp;
break;
case DW_OP_not:
svalue = *sp;
*sp = ~svalue;
break;
case DW_OP_or:
value = *sp--;
*sp |= value;
break;
case DW_OP_plus:
value = *sp--;
*sp += value;
break;
case DW_OP_plus_uconst:
// pop stack, add uelb128 constant, push result
*sp += addressSpace.getULEB128(p, expressionEnd);
break;
case DW_OP_shl:
value = *sp--;
*sp = *sp << value;
break;
case DW_OP_shr:
value = *sp--;
*sp = *sp >> value;
break;
case DW_OP_shra:
value = *sp--;
svalue = *sp;
*sp = svalue >> value;
break;
case DW_OP_xor:
value = *sp--;
*sp ^= value;
break;
case DW_OP_skip:
svalue = (int16_t)addressSpace.get16(p);
p += 2;
p += svalue;
break;
case DW_OP_bra:
svalue = (int16_t)addressSpace.get16(p);
p += 2;
if (*sp--)
p += svalue;
break;
case DW_OP_eq:
value = *sp--;
*sp = (*sp == value);
break;
case DW_OP_ge:
value = *sp--;
*sp = (*sp >= value);
break;
case DW_OP_gt:
value = *sp--;
*sp = (*sp > value);
break;
case DW_OP_le:
value = *sp--;
*sp = (*sp <= value);
break;
case DW_OP_lt:
value = *sp--;
*sp = (*sp < value);
break;
case DW_OP_ne:
value = *sp--;
*sp = (*sp != value);
break;
case DW_OP_lit0:
case DW_OP_lit1:
case DW_OP_lit2:
case DW_OP_lit3:
case DW_OP_lit4:
case DW_OP_lit5:
case DW_OP_lit6:
case DW_OP_lit7:
case DW_OP_lit8:
case DW_OP_lit9:
case DW_OP_lit10:
case DW_OP_lit11:
case DW_OP_lit12:
case DW_OP_lit13:
case DW_OP_lit14:
case DW_OP_lit15:
case DW_OP_lit16:
case DW_OP_lit17:
case DW_OP_lit18:
case DW_OP_lit19:
case DW_OP_lit20:
case DW_OP_lit21:
case DW_OP_lit22:
case DW_OP_lit23:
case DW_OP_lit24:
case DW_OP_lit25:
case DW_OP_lit26:
case DW_OP_lit27:
case DW_OP_lit28:
case DW_OP_lit29:
case DW_OP_lit30:
case DW_OP_lit31:
value = opcode - DW_OP_lit0;
*(++sp) = value;
break;
case DW_OP_reg0:
case DW_OP_reg1:
case DW_OP_reg2:
case DW_OP_reg3:
case DW_OP_reg4:
case DW_OP_reg5:
case DW_OP_reg6:
case DW_OP_reg7:
case DW_OP_reg8:
case DW_OP_reg9:
case DW_OP_reg10:
case DW_OP_reg11:
case DW_OP_reg12:
case DW_OP_reg13:
case DW_OP_reg14:
case DW_OP_reg15:
case DW_OP_reg16:
case DW_OP_reg17:
case DW_OP_reg18:
case DW_OP_reg19:
case DW_OP_reg20:
case DW_OP_reg21:
case DW_OP_reg22:
case DW_OP_reg23:
case DW_OP_reg24:
case DW_OP_reg25:
case DW_OP_reg26:
case DW_OP_reg27:
case DW_OP_reg28:
case DW_OP_reg29:
case DW_OP_reg30:
case DW_OP_reg31:
reg = opcode - DW_OP_reg0;
*(++sp) = registers.getRegister(reg);
break;
case DW_OP_regx:
reg = addressSpace.getULEB128(p, expressionEnd);
*(++sp) = registers.getRegister(reg);
break;
case DW_OP_breg0:
case DW_OP_breg1:
case DW_OP_breg2:
case DW_OP_breg3:
case DW_OP_breg4:
case DW_OP_breg5:
case DW_OP_breg6:
case DW_OP_breg7:
case DW_OP_breg8:
case DW_OP_breg9:
case DW_OP_breg10:
case DW_OP_breg11:
case DW_OP_breg12:
case DW_OP_breg13:
case DW_OP_breg14:
case DW_OP_breg15:
case DW_OP_breg16:
case DW_OP_breg17:
case DW_OP_breg18:
case DW_OP_breg19:
case DW_OP_breg20:
case DW_OP_breg21:
case DW_OP_breg22:
case DW_OP_breg23:
case DW_OP_breg24:
case DW_OP_breg25:
case DW_OP_breg26:
case DW_OP_breg27:
case DW_OP_breg28:
case DW_OP_breg29:
case DW_OP_breg30:
case DW_OP_breg31:
reg = opcode - DW_OP_breg0;
svalue = addressSpace.getSLEB128(p, expressionEnd);
*(++sp) = registers.getRegister(reg) + svalue;
break;
case DW_OP_bregx:
reg = addressSpace.getULEB128(p, expressionEnd);
svalue = addressSpace.getSLEB128(p, expressionEnd);
*(++sp) = registers.getRegister(reg) + svalue;
break;
case DW_OP_deref_size:
// pop stack, dereference, push result
value = *sp--;
switch (addressSpace.get8(p++)) {
case 1:
value = addressSpace.get8(value);
break;
case 2:
value = addressSpace.get16(value);
break;
case 4:
value = addressSpace.get32(value);
break;
case 8:
value = addressSpace.get64(value);
break;
default:
assert(0 && "DW_OP_deref_size with bad size");
}
*(++sp) = value;
break;
case DW_OP_fbreg:
case DW_OP_piece:
case DW_OP_xderef_size:
case DW_OP_nop:
case DW_OP_push_object_addres:
case DW_OP_call2:
case DW_OP_call4:
case DW_OP_call_ref:
default:
assert(0 && "dwarf opcode not implemented");
}
}
return *sp;
}
} // namespace _Unwind
#endif // __DWARF_INSTRUCTIONS_HPP__
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