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llvm-project/libunwind/src/DwarfParser.hpp
Oliver Hunt e6a1aff591
[runtimes][PAC] Harden unwinding when possible (#143230) 
This hardens the unwinding logic and datastructures on systems
that support pointer authentication.

The approach taken to hardening is to harden the schemas of as many
high value fields in the myriad structs as possible, and then also
explicitly qualify local variables referencing privileged or security
critical values.

This does introduce ABI linkage between libcxx, libcxxabi, and
libunwind but those are in principle separate from the OS itself
so we've kept the schema definitions in the library specific headers
rather than ptrauth.h
2025-10-20 09:57:45 -07:00

909 lines
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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//
// 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 "libunwind.h"
#include "dwarf2.h"
#include "Registers.hpp"
#include "config.h"
#if defined(_LIBUNWIND_TARGET_AARCH64_AUTHENTICATED_UNWINDING)
#include <ptrauth.h>
#endif
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;
typedef pint_t __ptrauth_unwind_cie_info_personality personality_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;
personality_t personality;
uint32_t codeAlignFactor;
int dataAlignFactor;
bool isSignalFrame;
bool fdesHaveAugmentationData;
uint8_t returnAddressRegister;
#if defined(_LIBUNWIND_TARGET_AARCH64)
bool addressesSignedWithBKey;
bool mteTaggedFrame;
#endif
};
/// 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,
kRegisterUndefined,
kRegisterInCFA,
kRegisterInCFADecrypt, // sparc64 specific
kRegisterOffsetFromCFA,
kRegisterInRegister,
kRegisterAtExpression,
kRegisterIsExpression
};
struct RegisterLocation {
RegisterSavedWhere location;
bool initialStateSaved;
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;
RegisterLocation savedRegisters[kMaxRegisterNumber + 1];
#if defined(_LIBUNWIND_TARGET_AARCH64)
pint_t ptrAuthDiversifier;
#endif
enum class InitializeTime { kLazy, kNormal };
// When saving registers, this data structure is lazily initialized.
PrologInfo(InitializeTime IT = InitializeTime::kNormal) {
if (IT == InitializeTime::kNormal)
memset(this, 0, sizeof(*this));
}
void checkSaveRegister(uint64_t reg, PrologInfo &initialState) {
if (!savedRegisters[reg].initialStateSaved) {
initialState.savedRegisters[reg] = savedRegisters[reg];
savedRegisters[reg].initialStateSaved = true;
}
}
void setRegister(uint64_t reg, RegisterSavedWhere newLocation,
int64_t newValue, PrologInfo &initialState) {
checkSaveRegister(reg, initialState);
savedRegisters[reg].location = newLocation;
savedRegisters[reg].value = newValue;
}
void setRegisterLocation(uint64_t reg, RegisterSavedWhere newLocation,
PrologInfo &initialState) {
checkSaveRegister(reg, initialState);
savedRegisters[reg].location = newLocation;
}
void setRegisterValue(uint64_t reg, int64_t newValue,
PrologInfo &initialState) {
checkSaveRegister(reg, initialState);
savedRegisters[reg].value = newValue;
}
void restoreRegisterToInitialState(uint64_t reg, PrologInfo &initialState) {
if (savedRegisters[reg].initialStateSaved)
savedRegisters[reg] = initialState.savedRegisters[reg];
// else the register still holds its initial state
}
};
struct PrologInfoStackEntry {
PrologInfoStackEntry(PrologInfoStackEntry *n, const PrologInfo &i)
: next(n), info(i) {}
PrologInfoStackEntry *next;
PrologInfo info;
};
struct RememberStack {
PrologInfoStackEntry *entry;
RememberStack() : entry(nullptr) {}
~RememberStack() {
#if defined(_LIBUNWIND_REMEMBER_CLEANUP_NEEDED)
// Clean up rememberStack. Even in the case where every
// DW_CFA_remember_state is paired with a DW_CFA_restore_state,
// parseInstructions can skip restore opcodes if it reaches the target PC
// and stops interpreting, so we have to make sure we don't leak memory.
while (entry) {
PrologInfoStackEntry *next = entry->next;
_LIBUNWIND_REMEMBER_FREE(entry);
entry = next;
}
#endif
}
};
static bool findFDE(A &addressSpace, pint_t pc, pint_t ehSectionStart,
size_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,
bool useCIEInfo = false);
static bool parseFDEInstructions(A &addressSpace, const FDE_Info &fdeInfo,
const CIE_Info &cieInfo, pint_t upToPC,
int arch, PrologInfo *results);
static const char *parseCIE(A &addressSpace, pint_t cie, CIE_Info *cieInfo);
};
/// Parse a FDE into a CIE_Info and an FDE_Info. If useCIEInfo is
/// true, treat cieInfo as already-parsed CIE_Info (whose start offset
/// must match the one specified by the FDE) rather than parsing the
/// one indicated within the FDE.
template <typename A>
const char *CFI_Parser<A>::decodeFDE(A &addressSpace, pint_t fdeStart,
FDE_Info *fdeInfo, CIE_Info *cieInfo,
bool useCIEInfo) {
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"; // zero terminator
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;
if (useCIEInfo) {
if (cieInfo->cieStart != cieStart)
return "CIE start does not match";
} else {
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,
size_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 = (sectionLength == SIZE_MAX)
? static_cast<pint_t>(-1)
: (ehSectionStart + 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; // zero terminator
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;
#if defined(_LIBUNWIND_TARGET_AARCH64)
cieInfo->addressesSignedWithBKey = false;
cieInfo->mteTaggedFrame = false;
#endif
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 alignment 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 = (version == 1) ? addressSpace.get8(p++)
: 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;
pint_t resultAddr = 0;
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);
pint_t personality = addressSpace.getEncodedP(
p, cieContentEnd, cieInfo->personalityEncoding,
/*datarelBase=*/0, &resultAddr);
#if defined(_LIBUNWIND_TARGET_AARCH64_AUTHENTICATED_UNWINDING)
if (personality) {
// The GOT for the personality function was signed address
// authenticated. Manually re-sign with the CIE_Info::personality
// schema. If we could guarantee the encoding of the personality we
// could avoid this by simply giving resultAddr the correct ptrauth
// schema and performing an assignment.
#if defined(__arm64e__)
const auto oldDiscriminator = resultAddr;
#else
const auto oldDiscriminator = ptrauth_blend_discriminator(
(void *)resultAddr, __ptrauth_unwind_pauthtest_personality_disc);
#endif
const auto discriminator = ptrauth_blend_discriminator(
&cieInfo->personality,
__ptrauth_unwind_cie_info_personality_disc);
void *signedPtr = ptrauth_auth_and_resign(
(void *)personality, ptrauth_key_function_pointer,
oldDiscriminator, ptrauth_key_function_pointer, discriminator);
personality = (pint_t)signedPtr;
}
#endif
// We use memmove to set the CIE personality as we have already
// re-signed the pointer to the correct schema.
memmove((void *)&cieInfo->personality, (void *)&personality,
sizeof(personality));
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;
#if defined(_LIBUNWIND_TARGET_AARCH64)
case 'B':
cieInfo->addressesSignedWithBKey = true;
break;
case 'G':
cieInfo->mteTaggedFrame = true;
break;
#endif
default:
// ignore unknown letters
break;
}
}
}
cieInfo->cieLength = cieContentEnd - cieInfo->cieStart;
cieInfo->cieInstructions = p;
return result;
}
/// "run" the DWARF instructions and create the abstract 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,
int arch, PrologInfo *results) {
// Alloca is used for the allocation of the rememberStack entries. It removes
// the dependency on new/malloc but the below for loop can not be refactored
// into functions. Entry could be saved during the processing of a CIE and
// restored by an FDE.
RememberStack rememberStack;
struct ParseInfo {
pint_t instructions;
pint_t instructionsEnd;
pint_t pcoffset;
};
ParseInfo parseInfoArray[] = {
{cieInfo.cieInstructions, cieInfo.cieStart + cieInfo.cieLength,
(pint_t)(-1)},
{fdeInfo.fdeInstructions, fdeInfo.fdeStart + fdeInfo.fdeLength,
upToPC - fdeInfo.pcStart}};
for (const auto &info : parseInfoArray) {
pint_t p = info.instructions;
pint_t instructionsEnd = info.instructionsEnd;
pint_t pcoffset = info.pcoffset;
pint_t codeOffset = 0;
// initialState initialized as registers in results are modified. Use
// PrologInfo accessor functions to avoid reading uninitialized data.
PrologInfo initialState(PrologInfo::InitializeTime::kLazy);
_LIBUNWIND_TRACE_DWARF("parseFDEInstructions(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;
++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) {
_LIBUNWIND_LOG0(
"malformed DW_CFA_offset_extended DWARF unwind, reg too big");
return false;
}
results->setRegister(reg, kRegisterInCFA, offset, initialState);
_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) {
_LIBUNWIND_LOG0(
"malformed DW_CFA_restore_extended DWARF unwind, reg too big");
return false;
}
results->restoreRegisterToInitialState(reg, initialState);
_LIBUNWIND_TRACE_DWARF("DW_CFA_restore_extended(reg=%" PRIu64 ")\n",
reg);
break;
case DW_CFA_undefined:
reg = addressSpace.getULEB128(p, instructionsEnd);
if (reg > kMaxRegisterNumber) {
_LIBUNWIND_LOG0(
"malformed DW_CFA_undefined DWARF unwind, reg too big");
return false;
}
results->setRegisterLocation(reg, kRegisterUndefined, initialState);
_LIBUNWIND_TRACE_DWARF("DW_CFA_undefined(reg=%" PRIu64 ")\n", reg);
break;
case DW_CFA_same_value:
reg = addressSpace.getULEB128(p, instructionsEnd);
if (reg > kMaxRegisterNumber) {
_LIBUNWIND_LOG0(
"malformed DW_CFA_same_value DWARF unwind, reg too big");
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->setRegisterLocation(reg, kRegisterUnused, initialState);
_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) {
_LIBUNWIND_LOG0(
"malformed DW_CFA_register DWARF unwind, reg too big");
return false;
}
if (reg2 > kMaxRegisterNumber) {
_LIBUNWIND_LOG0(
"malformed DW_CFA_register DWARF unwind, reg2 too big");
return false;
}
results->setRegister(reg, kRegisterInRegister, (int64_t)reg2,
initialState);
_LIBUNWIND_TRACE_DWARF(
"DW_CFA_register(reg=%" PRIu64 ", reg2=%" PRIu64 ")\n", reg, reg2);
break;
case DW_CFA_remember_state: {
// Avoid operator new because that would be an upward dependency.
// Avoid malloc because it needs heap allocation.
PrologInfoStackEntry *entry =
(PrologInfoStackEntry *)_LIBUNWIND_REMEMBER_ALLOC(
sizeof(PrologInfoStackEntry));
if (entry != NULL) {
entry->next = rememberStack.entry;
entry->info = *results;
rememberStack.entry = entry;
} else {
return false;
}
_LIBUNWIND_TRACE_DWARF("DW_CFA_remember_state\n");
break;
}
case DW_CFA_restore_state:
if (rememberStack.entry != NULL) {
PrologInfoStackEntry *top = rememberStack.entry;
*results = top->info;
rememberStack.entry = top->next;
_LIBUNWIND_REMEMBER_FREE(top);
} else {
return false;
}
_LIBUNWIND_TRACE_DWARF("DW_CFA_restore_state\n");
break;
case DW_CFA_def_cfa:
reg = addressSpace.getULEB128(p, instructionsEnd);
offset = (int64_t)addressSpace.getULEB128(p, instructionsEnd);
if (reg > kMaxRegisterNumber) {
_LIBUNWIND_LOG0("malformed DW_CFA_def_cfa DWARF unwind, reg too big");
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) {
_LIBUNWIND_LOG0(
"malformed DW_CFA_def_cfa_register DWARF unwind, reg too big");
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);
_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 < static_cast<pint_t>(~0) && "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) {
_LIBUNWIND_LOG0(
"malformed DW_CFA_expression DWARF unwind, reg too big");
return false;
}
results->setRegister(reg, kRegisterAtExpression, (int64_t)p,
initialState);
length = addressSpace.getULEB128(p, instructionsEnd);
assert(length < static_cast<pint_t>(~0) && "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) {
_LIBUNWIND_LOG0(
"malformed DW_CFA_offset_extended_sf DWARF unwind, reg too big");
return false;
}
offset = addressSpace.getSLEB128(p, instructionsEnd) *
cieInfo.dataAlignFactor;
results->setRegister(reg, kRegisterInCFA, offset, initialState);
_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) {
_LIBUNWIND_LOG0(
"malformed DW_CFA_def_cfa_sf DWARF unwind, reg too big");
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);
_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) {
_LIBUNWIND_LOG(
"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->setRegister(reg, kRegisterOffsetFromCFA, offset, initialState);
_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) {
_LIBUNWIND_LOG0(
"malformed DW_CFA_val_offset_sf DWARF unwind, reg too big");
return false;
}
offset = addressSpace.getSLEB128(p, instructionsEnd) *
cieInfo.dataAlignFactor;
results->setRegister(reg, kRegisterOffsetFromCFA, offset, initialState);
_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) {
_LIBUNWIND_LOG0(
"malformed DW_CFA_val_expression DWARF unwind, reg too big");
return false;
}
results->setRegister(reg, kRegisterIsExpression, (int64_t)p,
initialState);
length = addressSpace.getULEB128(p, instructionsEnd);
assert(length < static_cast<pint_t>(~0) && "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) {
_LIBUNWIND_LOG0("malformed DW_CFA_GNU_negative_offset_extended DWARF "
"unwind, reg too big");
return false;
}
offset = (int64_t)addressSpace.getULEB128(p, instructionsEnd) *
cieInfo.dataAlignFactor;
results->setRegister(reg, kRegisterInCFA, -offset, initialState);
_LIBUNWIND_TRACE_DWARF(
"DW_CFA_GNU_negative_offset_extended(%" PRId64 ")\n", offset);
break;
#if defined(_LIBUNWIND_TARGET_AARCH64) || defined(_LIBUNWIND_TARGET_SPARC) || \
defined(_LIBUNWIND_TARGET_SPARC64)
// The same constant is used to represent different instructions on
// AArch64 (negate_ra_state) and SPARC (window_save).
static_assert(DW_CFA_AARCH64_negate_ra_state == DW_CFA_GNU_window_save,
"uses the same constant");
case DW_CFA_AARCH64_negate_ra_state:
switch (arch) {
#if defined(_LIBUNWIND_TARGET_AARCH64)
case REGISTERS_ARM64: {
int64_t value =
results->savedRegisters[UNW_AARCH64_RA_SIGN_STATE].value ^ 0x1;
results->setRegisterValue(UNW_AARCH64_RA_SIGN_STATE, value,
initialState);
_LIBUNWIND_TRACE_DWARF("DW_CFA_AARCH64_negate_ra_state\n");
} break;
#endif
#if defined(_LIBUNWIND_TARGET_SPARC)
// case DW_CFA_GNU_window_save:
case REGISTERS_SPARC:
_LIBUNWIND_TRACE_DWARF("DW_CFA_GNU_window_save()\n");
for (reg = UNW_SPARC_O0; reg <= UNW_SPARC_O7; reg++) {
results->setRegister(reg, kRegisterInRegister,
((int64_t)reg - UNW_SPARC_O0) + UNW_SPARC_I0,
initialState);
}
for (reg = UNW_SPARC_L0; reg <= UNW_SPARC_I7; reg++) {
results->setRegister(reg, kRegisterInCFA,
((int64_t)reg - UNW_SPARC_L0) * 4,
initialState);
}
break;
#endif
#if defined(_LIBUNWIND_TARGET_SPARC64)
// case DW_CFA_GNU_window_save:
case REGISTERS_SPARC64:
// Don't save %o0-%o7 on sparc64.
// https://reviews.llvm.org/D32450#736405
for (reg = UNW_SPARC_L0; reg <= UNW_SPARC_I7; reg++) {
if (reg == UNW_SPARC_I7)
results->setRegister(
reg, kRegisterInCFADecrypt,
static_cast<int64_t>((reg - UNW_SPARC_L0) * sizeof(pint_t)),
initialState);
else
results->setRegister(
reg, kRegisterInCFA,
static_cast<int64_t>((reg - UNW_SPARC_L0) * sizeof(pint_t)),
initialState);
}
_LIBUNWIND_TRACE_DWARF("DW_CFA_GNU_window_save\n");
break;
#endif
}
break;
#if defined(_LIBUNWIND_TARGET_AARCH64)
case DW_CFA_AARCH64_negate_ra_state_with_pc: {
int64_t value =
results->savedRegisters[UNW_AARCH64_RA_SIGN_STATE].value ^ 0x3;
results->setRegisterValue(UNW_AARCH64_RA_SIGN_STATE, value,
initialState);
// When calculating the value of the PC, it is assumed that the CFI
// instruction is placed before the signing instruction, however it is
// placed after. Because of this, we need to take into account the CFI
// instruction is one instruction call later than expected, and reduce
// the PC value by 4 bytes to compensate.
results->ptrAuthDiversifier = fdeInfo.pcStart + codeOffset - 0x4;
_LIBUNWIND_TRACE_DWARF(
"DW_CFA_AARCH64_negate_ra_state_with_pc(pc=0x%" PRIx64 ")\n",
static_cast<uint64_t>(results->ptrAuthDiversifier));
} break;
#endif
#else
(void)arch;
#endif
default:
operand = opcode & 0x3F;
switch (opcode & 0xC0) {
case DW_CFA_offset:
reg = operand;
if (reg > kMaxRegisterNumber) {
_LIBUNWIND_LOG("malformed DW_CFA_offset DWARF unwind, reg (%" PRIu64
") out of range",
reg);
return false;
}
offset = (int64_t)addressSpace.getULEB128(p, instructionsEnd) *
cieInfo.dataAlignFactor;
results->setRegister(reg, kRegisterInCFA, offset, initialState);
_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) {
_LIBUNWIND_LOG(
"malformed DW_CFA_restore DWARF unwind, reg (%" PRIu64
") out of range",
reg);
return false;
}
results->restoreRegisterToInitialState(reg, initialState);
_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__
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