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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 <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include "dwarf2.h"
#include "Registers.hpp"
#include "DwarfParser.hpp"
#include "config.h"
namespace libunwind {
/// 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 int stepWithDwarf(A &addressSpace, pint_t pc, pint_t fdeStart,
R &registers);
private:
enum {
DW_X86_64_RET_ADDR = 16
};
enum {
DW_X86_RET_ADDR = 8
};
typedef typename CFI_Parser<A>::RegisterLocation RegisterLocation;
typedef typename CFI_Parser<A>::PrologInfo PrologInfo;
typedef typename CFI_Parser<A>::FDE_Info FDE_Info;
typedef typename CFI_Parser<A>::CIE_Info CIE_Info;
static pint_t evaluateExpression(pint_t expression, A &addressSpace,
const R &registers,
pint_t initialStackValue);
static pint_t getSavedRegister(A &addressSpace, const R &registers,
pint_t cfa, const RegisterLocation &savedReg);
static double getSavedFloatRegister(A &addressSpace, const R &registers,
pint_t cfa, const RegisterLocation &savedReg);
static v128 getSavedVectorRegister(A &addressSpace, const R &registers,
pint_t cfa, const RegisterLocation &savedReg);
static pint_t getCFA(A &addressSpace, const PrologInfo &prolog,
const R &registers) {
if (prolog.cfaRegister != 0)
return (pint_t)((sint_t)registers.getRegister((int)prolog.cfaRegister) +
prolog.cfaRegisterOffset);
if (prolog.cfaExpression != 0)
return evaluateExpression((pint_t)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 RegisterLocation &savedReg) {
switch (savedReg.location) {
case CFI_Parser<A>::kRegisterInCFA:
return addressSpace.getP(cfa + (pint_t)savedReg.value);
case CFI_Parser<A>::kRegisterAtExpression:
return addressSpace.getP(
evaluateExpression((pint_t)savedReg.value, addressSpace,
registers, cfa));
case CFI_Parser<A>::kRegisterIsExpression:
return evaluateExpression((pint_t)savedReg.value, addressSpace,
registers, cfa);
case CFI_Parser<A>::kRegisterInRegister:
return registers.getRegister((int)savedReg.value);
case CFI_Parser<A>::kRegisterUnused:
case CFI_Parser<A>::kRegisterOffsetFromCFA:
// FIX ME
break;
}
_LIBUNWIND_ABORT("unsupported restore location for register");
}
template <typename A, typename R>
double DwarfInstructions<A, R>::getSavedFloatRegister(
A &addressSpace, const R &registers, pint_t cfa,
const RegisterLocation &savedReg) {
switch (savedReg.location) {
case CFI_Parser<A>::kRegisterInCFA:
return addressSpace.getDouble(cfa + (pint_t)savedReg.value);
case CFI_Parser<A>::kRegisterAtExpression:
return addressSpace.getDouble(
evaluateExpression((pint_t)savedReg.value, addressSpace,
registers, cfa));
case CFI_Parser<A>::kRegisterIsExpression:
case CFI_Parser<A>::kRegisterUnused:
case CFI_Parser<A>::kRegisterOffsetFromCFA:
case CFI_Parser<A>::kRegisterInRegister:
// FIX ME
break;
}
_LIBUNWIND_ABORT("unsupported restore location for float register");
}
template <typename A, typename R>
v128 DwarfInstructions<A, R>::getSavedVectorRegister(
A &addressSpace, const R &registers, pint_t cfa,
const RegisterLocation &savedReg) {
switch (savedReg.location) {
case CFI_Parser<A>::kRegisterInCFA:
return addressSpace.getVector(cfa + (pint_t)savedReg.value);
case CFI_Parser<A>::kRegisterAtExpression:
return addressSpace.getVector(
evaluateExpression((pint_t)savedReg.value, addressSpace,
registers, cfa));
case CFI_Parser<A>::kRegisterIsExpression:
case CFI_Parser<A>::kRegisterUnused:
case CFI_Parser<A>::kRegisterOffsetFromCFA:
case CFI_Parser<A>::kRegisterInRegister:
// FIX ME
break;
}
_LIBUNWIND_ABORT("unsupported restore location for vector register");
}
template <typename A, typename R>
int DwarfInstructions<A, R>::stepWithDwarf(A &addressSpace, pint_t pc,
pint_t fdeStart, R &registers) {
FDE_Info fdeInfo;
CIE_Info cieInfo;
if (CFI_Parser<A>::decodeFDE(addressSpace, fdeStart, &fdeInfo,
&cieInfo) == NULL) {
PrologInfo prolog;
if (CFI_Parser<A>::parseFDEInstructions(addressSpace, fdeInfo, cieInfo, pc,
&prolog)) {
// get pointer to cfa (architecture specific)
pint_t cfa = getCFA(addressSpace, prolog, registers);
// restore registers that DWARF says were saved
R newRegisters = registers;
pint_t returnAddress = 0;
const int lastReg = R::lastDwarfRegNum();
assert(static_cast<int>(CFI_Parser<A>::kMaxRegisterNumber) >= lastReg &&
"register range too large");
assert(lastReg >= (int)cieInfo.returnAddressRegister &&
"register range does not contain return address register");
for (int i = 0; i <= lastReg; ++i) {
if (prolog.savedRegisters[i].location !=
CFI_Parser<A>::kRegisterUnused) {
if (registers.validFloatRegister(i))
newRegisters.setFloatRegister(
i, getSavedFloatRegister(addressSpace, registers, cfa,
prolog.savedRegisters[i]));
else if (registers.validVectorRegister(i))
newRegisters.setVectorRegister(
i, getSavedVectorRegister(addressSpace, registers, cfa,
prolog.savedRegisters[i]));
else 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
return UNW_EBADREG;
}
}
// By definition, the CFA is the stack pointer at the call site, so
// restoring SP means setting it to CFA.
newRegisters.setSP(cfa);
// Return address is address after call site instruction, so setting IP to
// that does simualates a return.
newRegisters.setIP(returnAddress);
// Simulate the step by replacing the register set with the new ones.
registers = newRegisters;
return UNW_STEP_SUCCESS;
}
}
return UNW_EBADFRAME;
}
template <typename A, typename R>
typename A::pint_t
DwarfInstructions<A, R>::evaluateExpression(pint_t expression, A &addressSpace,
const R &registers,
pint_t initialStackValue) {
const bool log = false;
pint_t p = expression;
pint_t expressionEnd = expression + 20; // temp, until len read
pint_t length = (pint_t)addressSpace.getULEB128(p, expressionEnd);
expressionEnd = p + length;
if (log)
fprintf(stderr, "evaluateExpression(): length=%" PRIu64 "\n",
(uint64_t)length);
pint_t stack[100];
pint_t *sp = stack;
*(++sp) = initialStackValue;
while (p < expressionEnd) {
if (log) {
for (pint_t *t = sp; t > stack; --t) {
fprintf(stderr, "sp[] = 0x%" PRIx64 "\n", (uint64_t)(*t));
}
}
uint8_t opcode = addressSpace.get8(p++);
sint_t svalue, svalue2;
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;
if (log)
fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
break;
case DW_OP_deref:
// pop stack, dereference, push result
value = *sp--;
*(++sp) = addressSpace.getP(value);
if (log)
fprintf(stderr, "dereference 0x%" PRIx64 "\n", (uint64_t)value);
break;
case DW_OP_const1u:
// push immediate 1 byte value
value = addressSpace.get8(p);
p += 1;
*(++sp) = value;
if (log)
fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
break;
case DW_OP_const1s:
// push immediate 1 byte signed value
svalue = (int8_t) addressSpace.get8(p);
p += 1;
*(++sp) = (pint_t)svalue;
if (log)
fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)svalue);
break;
case DW_OP_const2u:
// push immediate 2 byte value
value = addressSpace.get16(p);
p += 2;
*(++sp) = value;
if (log)
fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
break;
case DW_OP_const2s:
// push immediate 2 byte signed value
svalue = (int16_t) addressSpace.get16(p);
p += 2;
*(++sp) = (pint_t)svalue;
if (log)
fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)svalue);
break;
case DW_OP_const4u:
// push immediate 4 byte value
value = addressSpace.get32(p);
p += 4;
*(++sp) = value;
if (log)
fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
break;
case DW_OP_const4s:
// push immediate 4 byte signed value
svalue = (int32_t)addressSpace.get32(p);
p += 4;
*(++sp) = (pint_t)svalue;
if (log)
fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)svalue);
break;
case DW_OP_const8u:
// push immediate 8 byte value
value = (pint_t)addressSpace.get64(p);
p += 8;
*(++sp) = value;
if (log)
fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
break;
case DW_OP_const8s:
// push immediate 8 byte signed value
value = (pint_t)addressSpace.get64(p);
p += 8;
*(++sp) = value;
if (log)
fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
break;
case DW_OP_constu:
// push immediate ULEB128 value
value = (pint_t)addressSpace.getULEB128(p, expressionEnd);
*(++sp) = value;
if (log)
fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
break;
case DW_OP_consts:
// push immediate SLEB128 value
svalue = (sint_t)addressSpace.getSLEB128(p, expressionEnd);
*(++sp) = (pint_t)svalue;
if (log)
fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)svalue);
break;
case DW_OP_dup:
// push top of stack
value = *sp;
*(++sp) = value;
if (log)
fprintf(stderr, "duplicate top of stack\n");
break;
case DW_OP_drop:
// pop
--sp;
if (log)
fprintf(stderr, "pop top of stack\n");
break;
case DW_OP_over:
// dup second
value = sp[-1];
*(++sp) = value;
if (log)
fprintf(stderr, "duplicate second in stack\n");
break;
case DW_OP_pick:
// pick from
reg = addressSpace.get8(p);
p += 1;
value = sp[-reg];
*(++sp) = value;
if (log)
fprintf(stderr, "duplicate %d in stack\n", reg);
break;
case DW_OP_swap:
// swap top two
value = sp[0];
sp[0] = sp[-1];
sp[-1] = value;
if (log)
fprintf(stderr, "swap top of stack\n");
break;
case DW_OP_rot:
// rotate top three
value = sp[0];
sp[0] = sp[-1];
sp[-1] = sp[-2];
sp[-2] = value;
if (log)
fprintf(stderr, "rotate top three of stack\n");
break;
case DW_OP_xderef:
// pop stack, dereference, push result
value = *sp--;
*sp = *((pint_t*)value);
if (log)
fprintf(stderr, "x-dereference 0x%" PRIx64 "\n", (uint64_t)value);
break;
case DW_OP_abs:
svalue = (sint_t)*sp;
if (svalue < 0)
*sp = (pint_t)(-svalue);
if (log)
fprintf(stderr, "abs\n");
break;
case DW_OP_and:
value = *sp--;
*sp &= value;
if (log)
fprintf(stderr, "and\n");
break;
case DW_OP_div:
svalue = (sint_t)(*sp--);
svalue2 = (sint_t)*sp;
*sp = (pint_t)(svalue2 / svalue);
if (log)
fprintf(stderr, "div\n");
break;
case DW_OP_minus:
value = *sp--;
*sp = *sp - value;
if (log)
fprintf(stderr, "minus\n");
break;
case DW_OP_mod:
svalue = (sint_t)(*sp--);
svalue2 = (sint_t)*sp;
*sp = (pint_t)(svalue2 % svalue);
if (log)
fprintf(stderr, "module\n");
break;
case DW_OP_mul:
svalue = (sint_t)(*sp--);
svalue2 = (sint_t)*sp;
*sp = (pint_t)(svalue2 * svalue);
if (log)
fprintf(stderr, "mul\n");
break;
case DW_OP_neg:
*sp = 0 - *sp;
if (log)
fprintf(stderr, "neg\n");
break;
case DW_OP_not:
svalue = (sint_t)(*sp);
*sp = (pint_t)(~svalue);
if (log)
fprintf(stderr, "not\n");
break;
case DW_OP_or:
value = *sp--;
*sp |= value;
if (log)
fprintf(stderr, "or\n");
break;
case DW_OP_plus:
value = *sp--;
*sp += value;
if (log)
fprintf(stderr, "plus\n");
break;
case DW_OP_plus_uconst:
// pop stack, add uelb128 constant, push result
*sp += static_cast<pint_t>(addressSpace.getULEB128(p, expressionEnd));
if (log)
fprintf(stderr, "add constant\n");
break;
case DW_OP_shl:
value = *sp--;
*sp = *sp << value;
if (log)
fprintf(stderr, "shift left\n");
break;
case DW_OP_shr:
value = *sp--;
*sp = *sp >> value;
if (log)
fprintf(stderr, "shift left\n");
break;
case DW_OP_shra:
value = *sp--;
svalue = (sint_t)*sp;
*sp = (pint_t)(svalue >> value);
if (log)
fprintf(stderr, "shift left arithmetric\n");
break;
case DW_OP_xor:
value = *sp--;
*sp ^= value;
if (log)
fprintf(stderr, "xor\n");
break;
case DW_OP_skip:
svalue = (int16_t) addressSpace.get16(p);
p += 2;
p = (pint_t)((sint_t)p + svalue);
if (log)
fprintf(stderr, "skip %" PRIu64 "\n", (uint64_t)svalue);
break;
case DW_OP_bra:
svalue = (int16_t) addressSpace.get16(p);
p += 2;
if (*sp--)
p = (pint_t)((sint_t)p + svalue);
if (log)
fprintf(stderr, "bra %" PRIu64 "\n", (uint64_t)svalue);
break;
case DW_OP_eq:
value = *sp--;
*sp = (*sp == value);
if (log)
fprintf(stderr, "eq\n");
break;
case DW_OP_ge:
value = *sp--;
*sp = (*sp >= value);
if (log)
fprintf(stderr, "ge\n");
break;
case DW_OP_gt:
value = *sp--;
*sp = (*sp > value);
if (log)
fprintf(stderr, "gt\n");
break;
case DW_OP_le:
value = *sp--;
*sp = (*sp <= value);
if (log)
fprintf(stderr, "le\n");
break;
case DW_OP_lt:
value = *sp--;
*sp = (*sp < value);
if (log)
fprintf(stderr, "lt\n");
break;
case DW_OP_ne:
value = *sp--;
*sp = (*sp != value);
if (log)
fprintf(stderr, "ne\n");
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 = static_cast<pint_t>(opcode - DW_OP_lit0);
*(++sp) = value;
if (log)
fprintf(stderr, "push literal 0x%" PRIx64 "\n", (uint64_t)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 = static_cast<uint32_t>(opcode - DW_OP_reg0);
*(++sp) = registers.getRegister((int)reg);
if (log)
fprintf(stderr, "push reg %d\n", reg);
break;
case DW_OP_regx:
reg = static_cast<uint32_t>(addressSpace.getULEB128(p, expressionEnd));
*(++sp) = registers.getRegister((int)reg);
if (log)
fprintf(stderr, "push reg %d + 0x%" PRIx64 "\n", reg, (uint64_t)svalue);
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 = static_cast<uint32_t>(opcode - DW_OP_breg0);
svalue = (sint_t)addressSpace.getSLEB128(p, expressionEnd);
svalue += static_cast<sint_t>(registers.getRegister((int)reg));
*(++sp) = (pint_t)(svalue);
if (log)
fprintf(stderr, "push reg %d + 0x%" PRIx64 "\n", reg, (uint64_t)svalue);
break;
case DW_OP_bregx:
reg = static_cast<uint32_t>(addressSpace.getULEB128(p, expressionEnd));
svalue = (sint_t)addressSpace.getSLEB128(p, expressionEnd);
svalue += static_cast<sint_t>(registers.getRegister((int)reg));
*(++sp) = (pint_t)(svalue);
if (log)
fprintf(stderr, "push reg %d + 0x%" PRIx64 "\n", reg, (uint64_t)svalue);
break;
case DW_OP_fbreg:
_LIBUNWIND_ABORT("DW_OP_fbreg not implemented");
break;
case DW_OP_piece:
_LIBUNWIND_ABORT("DW_OP_piece not implemented");
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 = (pint_t)addressSpace.get64(value);
break;
default:
_LIBUNWIND_ABORT("DW_OP_deref_size with bad size");
}
*(++sp) = value;
if (log)
fprintf(stderr, "sized dereference 0x%" PRIx64 "\n", (uint64_t)value);
break;
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:
_LIBUNWIND_ABORT("DWARF opcode not implemented");
}
}
if (log)
fprintf(stderr, "expression evaluates to 0x%" PRIx64 "\n", (uint64_t)*sp);
return *sp;
}
} // namespace libunwind
#endif // __DWARF_INSTRUCTIONS_HPP__