//===--------------------------- DwarfParser.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.
//
//
// Parses DWARF CFIs (FDEs and CIEs).
//
//===----------------------------------------------------------------------===//
#ifndef __DWARF_PARSER_HPP__
#define __DWARF_PARSER_HPP__
#include <inttypes.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <limits>
#include "libunwind.h"
#include "dwarf2.h"
#include "config.h"
namespace libunwind {
/// CFI_Parser does basic parsing of a CFI (Call Frame Information) records.
/// See DWARF Spec for details:
/// http://refspecs.linuxbase.org/LSB_3.1.0/LSB-Core-generic/LSB-Core-generic/ehframechpt.html
///
template <typename A>
class CFI_Parser {
public:
typedef typename A::pint_t pint_t;
/// Information encoded in a CIE (Common Information Entry)
struct CIE_Info {
pint_t cieStart;
pint_t cieLength;
pint_t cieInstructions;
uint8_t pointerEncoding;
uint8_t lsdaEncoding;
uint8_t personalityEncoding;
uint8_t personalityOffsetInCIE;
pint_t personality;
uint32_t codeAlignFactor;
int dataAlignFactor;
bool isSignalFrame;
bool fdesHaveAugmentationData;
uint8_t returnAddressRegister;
};
/// Information about an FDE (Frame Description Entry)
struct FDE_Info {
pint_t fdeStart;
pint_t fdeLength;
pint_t fdeInstructions;
pint_t pcStart;
pint_t pcEnd;
pint_t lsda;
};
enum {
kMaxRegisterNumber = _LIBUNWIND_HIGHEST_DWARF_REGISTER
};
enum RegisterSavedWhere {
kRegisterUnused,
kRegisterInCFA,
kRegisterOffsetFromCFA,
kRegisterInRegister,
kRegisterAtExpression,
kRegisterIsExpression
};
struct RegisterLocation {
RegisterSavedWhere location;
int64_t value;
};
/// Information about a frame layout and registers saved determined
/// by "running" the DWARF FDE "instructions"
struct PrologInfo {
uint32_t cfaRegister;
int32_t cfaRegisterOffset; // CFA = (cfaRegister)+cfaRegisterOffset
int64_t cfaExpression; // CFA = expression
uint32_t spExtraArgSize;
uint32_t codeOffsetAtStackDecrement;
bool registersInOtherRegisters;
bool sameValueUsed;
RegisterLocation savedRegisters[kMaxRegisterNumber + 1];
};
struct PrologInfoStackEntry {
PrologInfoStackEntry(PrologInfoStackEntry *n, const PrologInfo &i)
: next(n), info(i) {}
PrologInfoStackEntry *next;
PrologInfo info;
};
static bool findFDE(A &addressSpace, pint_t pc, pint_t ehSectionStart,
uint32_t sectionLength, pint_t fdeHint, FDE_Info *fdeInfo,
CIE_Info *cieInfo);
static const char *decodeFDE(A &addressSpace, pint_t fdeStart,
FDE_Info *fdeInfo, CIE_Info *cieInfo);
static bool parseFDEInstructions(A &addressSpace, const FDE_Info &fdeInfo,
const CIE_Info &cieInfo, pint_t upToPC,
PrologInfo *results);
static const char *parseCIE(A &addressSpace, pint_t cie, CIE_Info *cieInfo);
private:
static bool parseInstructions(A &addressSpace, pint_t instructions,
pint_t instructionsEnd, const CIE_Info &cieInfo,
pint_t pcoffset,
PrologInfoStackEntry *&rememberStack,
PrologInfo *results);
};
/// Parse a FDE into a CIE_Info and an FDE_Info
template <typename A>
const char *CFI_Parser<A>::decodeFDE(A &addressSpace, pint_t fdeStart,
FDE_Info *fdeInfo, CIE_Info *cieInfo) {
pint_t p = fdeStart;
pint_t cfiLength = (pint_t)addressSpace.get32(p);
p += 4;
if (cfiLength == 0xffffffff) {
// 0xffffffff means length is really next 8 bytes
cfiLength = (pint_t)addressSpace.get64(p);
p += 8;
}
if (cfiLength == 0)
return "FDE has zero length"; // end marker
uint32_t ciePointer = addressSpace.get32(p);
if (ciePointer == 0)
return "FDE is really a CIE"; // this is a CIE not an FDE
pint_t nextCFI = p + cfiLength;
pint_t cieStart = p - ciePointer;
const char *err = parseCIE(addressSpace, cieStart, cieInfo);
if (err != NULL)
return err;
p += 4;
// Parse pc begin and range.
pint_t pcStart =
addressSpace.getEncodedP(p, nextCFI, cieInfo->pointerEncoding);
pint_t pcRange =
addressSpace.getEncodedP(p, nextCFI, cieInfo->pointerEncoding & 0x0F);
// Parse rest of info.
fdeInfo->lsda = 0;
// Check for augmentation length.
if (cieInfo->fdesHaveAugmentationData) {
pint_t augLen = (pint_t)addressSpace.getULEB128(p, nextCFI);
pint_t endOfAug = p + augLen;
if (cieInfo->lsdaEncoding != DW_EH_PE_omit) {
// Peek at value (without indirection). Zero means no LSDA.
pint_t lsdaStart = p;
if (addressSpace.getEncodedP(p, nextCFI, cieInfo->lsdaEncoding & 0x0F) !=
0) {
// Reset pointer and re-parse LSDA address.
p = lsdaStart;
fdeInfo->lsda =
addressSpace.getEncodedP(p, nextCFI, cieInfo->lsdaEncoding);
}
}
p = endOfAug;
}
fdeInfo->fdeStart = fdeStart;
fdeInfo->fdeLength = nextCFI - fdeStart;
fdeInfo->fdeInstructions = p;
fdeInfo->pcStart = pcStart;
fdeInfo->pcEnd = pcStart + pcRange;
return NULL; // success
}
/// Scan an eh_frame section to find an FDE for a pc
template <typename A>
bool CFI_Parser<A>::findFDE(A &addressSpace, pint_t pc, pint_t ehSectionStart,
uint32_t sectionLength, pint_t fdeHint,
FDE_Info *fdeInfo, CIE_Info *cieInfo) {
//fprintf(stderr, "findFDE(0x%llX)\n", (long long)pc);
pint_t p = (fdeHint != 0) ? fdeHint : ehSectionStart;
const pint_t ehSectionEnd = p + sectionLength;
while (p < ehSectionEnd) {
pint_t currentCFI = p;
//fprintf(stderr, "findFDE() CFI at 0x%llX\n", (long long)p);
pint_t cfiLength = addressSpace.get32(p);
p += 4;
if (cfiLength == 0xffffffff) {
// 0xffffffff means length is really next 8 bytes
cfiLength = (pint_t)addressSpace.get64(p);
p += 8;
}
if (cfiLength == 0)
return false; // end marker
uint32_t id = addressSpace.get32(p);
if (id == 0) {
// Skip over CIEs.
p += cfiLength;
} else {
// Process FDE to see if it covers pc.
pint_t nextCFI = p + cfiLength;
uint32_t ciePointer = addressSpace.get32(p);
pint_t cieStart = p - ciePointer;
// Validate pointer to CIE is within section.
if ((ehSectionStart <= cieStart) && (cieStart < ehSectionEnd)) {
if (parseCIE(addressSpace, cieStart, cieInfo) == NULL) {
p += 4;
// Parse pc begin and range.
pint_t pcStart =
addressSpace.getEncodedP(p, nextCFI, cieInfo->pointerEncoding);
pint_t pcRange = addressSpace.getEncodedP(
p, nextCFI, cieInfo->pointerEncoding & 0x0F);
// Test if pc is within the function this FDE covers.
if ((pcStart < pc) && (pc <= pcStart + pcRange)) {
// parse rest of info
fdeInfo->lsda = 0;
// check for augmentation length
if (cieInfo->fdesHaveAugmentationData) {
pint_t augLen = (pint_t)addressSpace.getULEB128(p, nextCFI);
pint_t endOfAug = p + augLen;
if (cieInfo->lsdaEncoding != DW_EH_PE_omit) {
// Peek at value (without indirection). Zero means no LSDA.
pint_t lsdaStart = p;
if (addressSpace.getEncodedP(
p, nextCFI, cieInfo->lsdaEncoding & 0x0F) != 0) {
// Reset pointer and re-parse LSDA address.
p = lsdaStart;
fdeInfo->lsda = addressSpace
.getEncodedP(p, nextCFI, cieInfo->lsdaEncoding);
}
}
p = endOfAug;
}
fdeInfo->fdeStart = currentCFI;
fdeInfo->fdeLength = nextCFI - currentCFI;
fdeInfo->fdeInstructions = p;
fdeInfo->pcStart = pcStart;
fdeInfo->pcEnd = pcStart + pcRange;
return true;
} else {
// pc is not in begin/range, skip this FDE
}
} else {
// Malformed CIE, now augmentation describing pc range encoding.
}
} else {
// malformed FDE. CIE is bad
}
p = nextCFI;
}
}
return false;
}
/// Extract info from a CIE
template <typename A>
const char *CFI_Parser<A>::parseCIE(A &addressSpace, pint_t cie,
CIE_Info *cieInfo) {
cieInfo->pointerEncoding = 0;
cieInfo->lsdaEncoding = DW_EH_PE_omit;
cieInfo->personalityEncoding = 0;
cieInfo->personalityOffsetInCIE = 0;
cieInfo->personality = 0;
cieInfo->codeAlignFactor = 0;
cieInfo->dataAlignFactor = 0;
cieInfo->isSignalFrame = false;
cieInfo->fdesHaveAugmentationData = false;
cieInfo->cieStart = cie;
pint_t p = cie;
pint_t cieLength = (pint_t)addressSpace.get32(p);
p += 4;
pint_t cieContentEnd = p + cieLength;
if (cieLength == 0xffffffff) {
// 0xffffffff means length is really next 8 bytes
cieLength = (pint_t)addressSpace.get64(p);
p += 8;
cieContentEnd = p + cieLength;
}
if (cieLength == 0)
return NULL;
// CIE ID is always 0
if (addressSpace.get32(p) != 0)
return "CIE ID is not zero";
p += 4;
// Version is always 1 or 3
uint8_t version = addressSpace.get8(p);
if ((version != 1) && (version != 3))
return "CIE version is not 1 or 3";
++p;
// save start of augmentation string and find end
pint_t strStart = p;
while (addressSpace.get8(p) != 0)
++p;
++p;
// parse code aligment factor
cieInfo->codeAlignFactor = (uint32_t)addressSpace.getULEB128(p, cieContentEnd);
// parse data alignment factor
cieInfo->dataAlignFactor = (int)addressSpace.getSLEB128(p, cieContentEnd);
// parse return address register
uint64_t raReg = addressSpace.getULEB128(p, cieContentEnd);
assert(raReg < 255 && "return address register too large");
cieInfo->returnAddressRegister = (uint8_t)raReg;
// parse augmentation data based on augmentation string
const char *result = NULL;
if (addressSpace.get8(strStart) == 'z') {
// parse augmentation data length
addressSpace.getULEB128(p, cieContentEnd);
for (pint_t s = strStart; addressSpace.get8(s) != '\0'; ++s) {
switch (addressSpace.get8(s)) {
case 'z':
cieInfo->fdesHaveAugmentationData = true;
break;
case 'P':
cieInfo->personalityEncoding = addressSpace.get8(p);
++p;
cieInfo->personalityOffsetInCIE = (uint8_t)(p - cie);
cieInfo->personality = addressSpace
.getEncodedP(p, cieContentEnd, cieInfo->personalityEncoding);
break;
case 'L':
cieInfo->lsdaEncoding = addressSpace.get8(p);
++p;
break;
case 'R':
cieInfo->pointerEncoding = addressSpace.get8(p);
++p;
break;
case 'S':
cieInfo->isSignalFrame = true;
break;
default:
// ignore unknown letters
break;
}
}
}
cieInfo->cieLength = cieContentEnd - cieInfo->cieStart;
cieInfo->cieInstructions = p;
return result;
}
/// "run" the DWARF instructions and create the abstact PrologInfo for an FDE
template <typename A>
bool CFI_Parser<A>::parseFDEInstructions(A &addressSpace,
const FDE_Info &fdeInfo,
const CIE_Info &cieInfo, pint_t upToPC,
PrologInfo *results) {
// clear results
memset(results, '\0', sizeof(PrologInfo));
PrologInfoStackEntry *rememberStack = NULL;
// parse CIE then FDE instructions
return parseInstructions(addressSpace, cieInfo.cieInstructions,
cieInfo.cieStart + cieInfo.cieLength, cieInfo,
(pint_t)(-1), rememberStack, results) &&
parseInstructions(addressSpace, fdeInfo.fdeInstructions,
fdeInfo.fdeStart + fdeInfo.fdeLength, cieInfo,
upToPC - fdeInfo.pcStart, rememberStack, results);
}
/// "run" the DWARF instructions
template <typename A>
bool CFI_Parser<A>::parseInstructions(A &addressSpace, pint_t instructions,
pint_t instructionsEnd,
const CIE_Info &cieInfo, pint_t pcoffset,
PrologInfoStackEntry *&rememberStack,
PrologInfo *results) {
pint_t p = instructions;
pint_t codeOffset = 0;
PrologInfo initialState = *results;
_LIBUNWIND_TRACE_DWARF("parseInstructions(instructions=0x%0" PRIx64 ")\n",
static_cast<uint64_t>(instructionsEnd));
// see DWARF Spec, section 6.4.2 for details on unwind opcodes
while ((p < instructionsEnd) && (codeOffset < pcoffset)) {
uint64_t reg;
uint64_t reg2;
int64_t offset;
uint64_t length;
uint8_t opcode = addressSpace.get8(p);
uint8_t operand;
#if !defined(_LIBUNWIND_NO_HEAP)
PrologInfoStackEntry *entry;
#endif
++p;
switch (opcode) {
case DW_CFA_nop:
_LIBUNWIND_TRACE_DWARF("DW_CFA_nop\n");
break;
case DW_CFA_set_loc:
codeOffset =
addressSpace.getEncodedP(p, instructionsEnd, cieInfo.pointerEncoding);
_LIBUNWIND_TRACE_DWARF("DW_CFA_set_loc\n");
break;
case DW_CFA_advance_loc1:
codeOffset += (addressSpace.get8(p) * cieInfo.codeAlignFactor);
p += 1;
_LIBUNWIND_TRACE_DWARF("DW_CFA_advance_loc1: new offset=%" PRIu64 "\n",
static_cast<uint64_t>(codeOffset));
break;
case DW_CFA_advance_loc2:
codeOffset += (addressSpace.get16(p) * cieInfo.codeAlignFactor);
p += 2;
_LIBUNWIND_TRACE_DWARF("DW_CFA_advance_loc2: new offset=%" PRIu64 "\n",
static_cast<uint64_t>(codeOffset));
break;
case DW_CFA_advance_loc4:
codeOffset += (addressSpace.get32(p) * cieInfo.codeAlignFactor);
p += 4;
_LIBUNWIND_TRACE_DWARF("DW_CFA_advance_loc4: new offset=%" PRIu64 "\n",
static_cast<uint64_t>(codeOffset));
break;
case DW_CFA_offset_extended:
reg = addressSpace.getULEB128(p, instructionsEnd);
offset = (int64_t)addressSpace.getULEB128(p, instructionsEnd)
* cieInfo.dataAlignFactor;
if (reg > kMaxRegisterNumber) {
fprintf(stderr,
"malformed DW_CFA_offset_extended DWARF unwind, reg too big\n");
return false;
}
results->savedRegisters[reg].location = kRegisterInCFA;
results->savedRegisters[reg].value = offset;
_LIBUNWIND_TRACE_DWARF("DW_CFA_offset_extended(reg=%" PRIu64 ", "
"offset=%" PRId64 ")\n",
reg, offset);
break;
case DW_CFA_restore_extended:
reg = addressSpace.getULEB128(p, instructionsEnd);
if (reg > kMaxRegisterNumber) {
fprintf(
stderr,
"malformed DW_CFA_restore_extended DWARF unwind, reg too big\n");
return false;
}
results->savedRegisters[reg] = initialState.savedRegisters[reg];
_LIBUNWIND_TRACE_DWARF("DW_CFA_restore_extended(reg=%" PRIu64 ")\n", reg);
break;
case DW_CFA_undefined:
reg = addressSpace.getULEB128(p, instructionsEnd);
if (reg > kMaxRegisterNumber) {
fprintf(stderr,
"malformed DW_CFA_undefined DWARF unwind, reg too big\n");
return false;
}
results->savedRegisters[reg].location = kRegisterUnused;
_LIBUNWIND_TRACE_DWARF("DW_CFA_undefined(reg=%" PRIu64 ")\n", reg);
break;
case DW_CFA_same_value:
reg = addressSpace.getULEB128(p, instructionsEnd);
if (reg > kMaxRegisterNumber) {
fprintf(stderr,
"malformed DW_CFA_same_value DWARF unwind, reg too big\n");
return false;
}
// <rdar://problem/8456377> DW_CFA_same_value unsupported
// "same value" means register was stored in frame, but its current
// value has not changed, so no need to restore from frame.
// We model this as if the register was never saved.
results->savedRegisters[reg].location = kRegisterUnused;
// set flag to disable conversion to compact unwind
results->sameValueUsed = true;
_LIBUNWIND_TRACE_DWARF("DW_CFA_same_value(reg=%" PRIu64 ")\n", reg);
break;
case DW_CFA_register:
reg = addressSpace.getULEB128(p, instructionsEnd);
reg2 = addressSpace.getULEB128(p, instructionsEnd);
if (reg > kMaxRegisterNumber) {
fprintf(stderr,
"malformed DW_CFA_register DWARF unwind, reg too big\n");
return false;
}
if (reg2 > kMaxRegisterNumber) {
fprintf(stderr,
"malformed DW_CFA_register DWARF unwind, reg2 too big\n");
return false;
}
results->savedRegisters[reg].location = kRegisterInRegister;
results->savedRegisters[reg].value = (int64_t)reg2;
// set flag to disable conversion to compact unwind
results->registersInOtherRegisters = true;
_LIBUNWIND_TRACE_DWARF(
"DW_CFA_register(reg=%" PRIu64 ", reg2=%" PRIu64 ")\n", reg, reg2);
break;
#if !defined(_LIBUNWIND_NO_HEAP)
case DW_CFA_remember_state:
// avoid operator new, because that would be an upward dependency
entry = (PrologInfoStackEntry *)malloc(sizeof(PrologInfoStackEntry));
if (entry != NULL) {
entry->next = rememberStack;
entry->info = *results;
rememberStack = entry;
} else {
return false;
}
_LIBUNWIND_TRACE_DWARF("DW_CFA_remember_state\n");
break;
case DW_CFA_restore_state:
if (rememberStack != NULL) {
PrologInfoStackEntry *top = rememberStack;
*results = top->info;
rememberStack = top->next;
free((char *)top);
} else {
return false;
}
_LIBUNWIND_TRACE_DWARF("DW_CFA_restore_state\n");
break;
#endif
case DW_CFA_def_cfa:
reg = addressSpace.getULEB128(p, instructionsEnd);
offset = (int64_t)addressSpace.getULEB128(p, instructionsEnd);
if (reg > kMaxRegisterNumber) {
fprintf(stderr, "malformed DW_CFA_def_cfa DWARF unwind, reg too big\n");
return false;
}
results->cfaRegister = (uint32_t)reg;
results->cfaRegisterOffset = (int32_t)offset;
_LIBUNWIND_TRACE_DWARF(
"DW_CFA_def_cfa(reg=%" PRIu64 ", offset=%" PRIu64 ")\n", reg, offset);
break;
case DW_CFA_def_cfa_register:
reg = addressSpace.getULEB128(p, instructionsEnd);
if (reg > kMaxRegisterNumber) {
fprintf(
stderr,
"malformed DW_CFA_def_cfa_register DWARF unwind, reg too big\n");
return false;
}
results->cfaRegister = (uint32_t)reg;
_LIBUNWIND_TRACE_DWARF("DW_CFA_def_cfa_register(%" PRIu64 ")\n", reg);
break;
case DW_CFA_def_cfa_offset:
results->cfaRegisterOffset = (int32_t)
addressSpace.getULEB128(p, instructionsEnd);
results->codeOffsetAtStackDecrement = (uint32_t)codeOffset;
_LIBUNWIND_TRACE_DWARF("DW_CFA_def_cfa_offset(%d)\n",
results->cfaRegisterOffset);
break;
case DW_CFA_def_cfa_expression:
results->cfaRegister = 0;
results->cfaExpression = (int64_t)p;
length = addressSpace.getULEB128(p, instructionsEnd);
assert(length < std::numeric_limits<pint_t>::max() && "pointer overflow");
p += static_cast<pint_t>(length);
_LIBUNWIND_TRACE_DWARF("DW_CFA_def_cfa_expression(expression=0x%" PRIx64
", length=%" PRIu64 ")\n",
results->cfaExpression, length);
break;
case DW_CFA_expression:
reg = addressSpace.getULEB128(p, instructionsEnd);
if (reg > kMaxRegisterNumber) {
fprintf(stderr,
"malformed DW_CFA_expression DWARF unwind, reg too big\n");
return false;
}
results->savedRegisters[reg].location = kRegisterAtExpression;
results->savedRegisters[reg].value = (int64_t)p;
length = addressSpace.getULEB128(p, instructionsEnd);
assert(length < std::numeric_limits<pint_t>::max() && "pointer overflow");
p += static_cast<pint_t>(length);
_LIBUNWIND_TRACE_DWARF("DW_CFA_expression(reg=%" PRIu64 ", "
"expression=0x%" PRIx64 ", "
"length=%" PRIu64 ")\n",
reg, results->savedRegisters[reg].value, length);
break;
case DW_CFA_offset_extended_sf:
reg = addressSpace.getULEB128(p, instructionsEnd);
if (reg > kMaxRegisterNumber) {
fprintf(
stderr,
"malformed DW_CFA_offset_extended_sf DWARF unwind, reg too big\n");
return false;
}
offset =
addressSpace.getSLEB128(p, instructionsEnd) * cieInfo.dataAlignFactor;
results->savedRegisters[reg].location = kRegisterInCFA;
results->savedRegisters[reg].value = offset;
_LIBUNWIND_TRACE_DWARF("DW_CFA_offset_extended_sf(reg=%" PRIu64 ", "
"offset=%" PRId64 ")\n",
reg, offset);
break;
case DW_CFA_def_cfa_sf:
reg = addressSpace.getULEB128(p, instructionsEnd);
offset =
addressSpace.getSLEB128(p, instructionsEnd) * cieInfo.dataAlignFactor;
if (reg > kMaxRegisterNumber) {
fprintf(stderr,
"malformed DW_CFA_def_cfa_sf DWARF unwind, reg too big\n");
return false;
}
results->cfaRegister = (uint32_t)reg;
results->cfaRegisterOffset = (int32_t)offset;
_LIBUNWIND_TRACE_DWARF("DW_CFA_def_cfa_sf(reg=%" PRIu64 ", "
"offset=%" PRId64 ")\n",
reg, offset);
break;
case DW_CFA_def_cfa_offset_sf:
results->cfaRegisterOffset = (int32_t)
(addressSpace.getSLEB128(p, instructionsEnd) * cieInfo.dataAlignFactor);
results->codeOffsetAtStackDecrement = (uint32_t)codeOffset;
_LIBUNWIND_TRACE_DWARF("DW_CFA_def_cfa_offset_sf(%d)\n",
results->cfaRegisterOffset);
break;
case DW_CFA_val_offset:
reg = addressSpace.getULEB128(p, instructionsEnd);
if (reg > kMaxRegisterNumber) {
fprintf(stderr,
"malformed DW_CFA_val_offset DWARF unwind, reg (%" PRIu64
") out of range\n",
reg);
return false;
}
offset = (int64_t)addressSpace.getULEB128(p, instructionsEnd)
* cieInfo.dataAlignFactor;
results->savedRegisters[reg].location = kRegisterOffsetFromCFA;
results->savedRegisters[reg].value = offset;
_LIBUNWIND_TRACE_DWARF("DW_CFA_val_offset(reg=%" PRIu64 ", "
"offset=%" PRId64 "\n",
reg, offset);
break;
case DW_CFA_val_offset_sf:
reg = addressSpace.getULEB128(p, instructionsEnd);
if (reg > kMaxRegisterNumber) {
fprintf(stderr,
"malformed DW_CFA_val_offset_sf DWARF unwind, reg too big\n");
return false;
}
offset =
addressSpace.getSLEB128(p, instructionsEnd) * cieInfo.dataAlignFactor;
results->savedRegisters[reg].location = kRegisterOffsetFromCFA;
results->savedRegisters[reg].value = offset;
_LIBUNWIND_TRACE_DWARF("DW_CFA_val_offset_sf(reg=%" PRIu64 ", "
"offset=%" PRId64 "\n",
reg, offset);
break;
case DW_CFA_val_expression:
reg = addressSpace.getULEB128(p, instructionsEnd);
if (reg > kMaxRegisterNumber) {
fprintf(stderr,
"malformed DW_CFA_val_expression DWARF unwind, reg too big\n");
return false;
}
results->savedRegisters[reg].location = kRegisterIsExpression;
results->savedRegisters[reg].value = (int64_t)p;
length = addressSpace.getULEB128(p, instructionsEnd);
assert(length < std::numeric_limits<pint_t>::max() && "pointer overflow");
p += static_cast<pint_t>(length);
_LIBUNWIND_TRACE_DWARF("DW_CFA_val_expression(reg=%" PRIu64 ", "
"expression=0x%" PRIx64 ", length=%" PRIu64 ")\n",
reg, results->savedRegisters[reg].value, length);
break;
case DW_CFA_GNU_args_size:
length = addressSpace.getULEB128(p, instructionsEnd);
results->spExtraArgSize = (uint32_t)length;
_LIBUNWIND_TRACE_DWARF("DW_CFA_GNU_args_size(%" PRIu64 ")\n", length);
break;
case DW_CFA_GNU_negative_offset_extended:
reg = addressSpace.getULEB128(p, instructionsEnd);
if (reg > kMaxRegisterNumber) {
fprintf(stderr, "malformed DW_CFA_GNU_negative_offset_extended DWARF "
"unwind, reg too big\n");
return false;
}
offset = (int64_t)addressSpace.getULEB128(p, instructionsEnd)
* cieInfo.dataAlignFactor;
results->savedRegisters[reg].location = kRegisterInCFA;
results->savedRegisters[reg].value = -offset;
_LIBUNWIND_TRACE_DWARF(
"DW_CFA_GNU_negative_offset_extended(%" PRId64 ")\n", offset);
break;
default:
operand = opcode & 0x3F;
switch (opcode & 0xC0) {
case DW_CFA_offset:
reg = operand;
if (reg > kMaxRegisterNumber) {
fprintf(stderr, "malformed DW_CFA_offset DWARF unwind, reg (%" PRIu64
") out of range\n",
reg);
return false;
}
offset = (int64_t)addressSpace.getULEB128(p, instructionsEnd)
* cieInfo.dataAlignFactor;
results->savedRegisters[reg].location = kRegisterInCFA;
results->savedRegisters[reg].value = offset;
_LIBUNWIND_TRACE_DWARF("DW_CFA_offset(reg=%d, offset=%" PRId64 ")\n",
operand, offset);
break;
case DW_CFA_advance_loc:
codeOffset += operand * cieInfo.codeAlignFactor;
_LIBUNWIND_TRACE_DWARF("DW_CFA_advance_loc: new offset=%" PRIu64 "\n",
static_cast<uint64_t>(codeOffset));
break;
case DW_CFA_restore:
reg = operand;
if (reg > kMaxRegisterNumber) {
fprintf(stderr, "malformed DW_CFA_restore DWARF unwind, reg (%" PRIu64
") out of range\n",
reg);
return false;
}
results->savedRegisters[reg] = initialState.savedRegisters[reg];
_LIBUNWIND_TRACE_DWARF("DW_CFA_restore(reg=%" PRIu64 ")\n",
static_cast<uint64_t>(operand));
break;
default:
_LIBUNWIND_TRACE_DWARF("unknown CFA opcode 0x%02X\n", opcode);
return false;
}
}
}
return true;
}
} // namespace libunwind
#endif // __DWARF_PARSER_HPP__