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Diffstat (limited to 'system/lib/libcxxabi/src/Unwind/DwarfParser.hpp')
| -rw-r--r-- | system/lib/libcxxabi/src/Unwind/DwarfParser.hpp | 713 |
1 files changed, 713 insertions, 0 deletions
diff --git a/system/lib/libcxxabi/src/Unwind/DwarfParser.hpp b/system/lib/libcxxabi/src/Unwind/DwarfParser.hpp new file mode 100644 index 00000000..152baab9 --- /dev/null +++ b/system/lib/libcxxabi/src/Unwind/DwarfParser.hpp @@ -0,0 +1,713 @@ +//===--------------------------- 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 <stdint.h> +#include <stdio.h> +#include <stdlib.h> + +#include <vector> + +#include "libunwind.h" +#include "dwarf2.h" + +#include "AddressSpace.hpp" + +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; + }; + + /// 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 = 120 + }; + 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]; + }; + + 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 != 0) { + // 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 != 0) { + // 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 = 0; + 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 + addressSpace.getULEB128(p, cieContentEnd); + // 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 + bzero(results, 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) { + const bool logDwarf = false; + pint_t p = instructions; + pint_t codeOffset = 0; + PrologInfo initialState = *results; + if (logDwarf) + fprintf(stderr, "parseInstructions(instructions=0x%0llX)\n", + (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; + PrologInfoStackEntry *entry; + ++p; + switch (opcode) { + case DW_CFA_nop: + if (logDwarf) + fprintf(stderr, "DW_CFA_nop\n"); + break; + case DW_CFA_set_loc: + codeOffset = + addressSpace.getEncodedP(p, instructionsEnd, cieInfo.pointerEncoding); + if (logDwarf) + fprintf(stderr, "DW_CFA_set_loc\n"); + break; + case DW_CFA_advance_loc1: + codeOffset += (addressSpace.get8(p) * cieInfo.codeAlignFactor); + p += 1; + if (logDwarf) + fprintf(stderr, "DW_CFA_advance_loc1: new offset=%llu\n", + (uint64_t)codeOffset); + break; + case DW_CFA_advance_loc2: + codeOffset += (addressSpace.get16(p) * cieInfo.codeAlignFactor); + p += 2; + if (logDwarf) + fprintf(stderr, "DW_CFA_advance_loc2: new offset=%llu\n", + (uint64_t)codeOffset); + break; + case DW_CFA_advance_loc4: + codeOffset += (addressSpace.get32(p) * cieInfo.codeAlignFactor); + p += 4; + if (logDwarf) + fprintf(stderr, "DW_CFA_advance_loc4: new offset=%llu\n", + (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; + if (logDwarf) + fprintf(stderr, "DW_CFA_offset_extended(reg=%lld, offset=%lld)\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]; + if (logDwarf) + fprintf(stderr, "DW_CFA_restore_extended(reg=%lld)\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; + if (logDwarf) + fprintf(stderr, "DW_CFA_undefined(reg=%lld)\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; + if (logDwarf) + fprintf(stderr, "DW_CFA_same_value(reg=%lld)\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; + if (logDwarf) + fprintf(stderr, "DW_CFA_register(reg=%lld, reg2=%lld)\n", reg, reg2); + break; + 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; + } + if (logDwarf) + fprintf(stderr, "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; + } + if (logDwarf) + fprintf(stderr, "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) { + 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; + if (logDwarf) + fprintf(stderr, "DW_CFA_def_cfa(reg=%lld, offset=%lld)\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; + if (logDwarf) + fprintf(stderr, "DW_CFA_def_cfa_register(%lld)\n", reg); + break; + case DW_CFA_def_cfa_offset: + results->cfaRegisterOffset = (int32_t) + addressSpace.getULEB128(p, instructionsEnd); + results->codeOffsetAtStackDecrement = (uint32_t)codeOffset; + if (logDwarf) + fprintf(stderr, "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); + p += length; + if (logDwarf) + fprintf(stderr, + "DW_CFA_def_cfa_expression(expression=0x%llX, length=%llu)\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); + p += length; + if (logDwarf) + fprintf(stderr, + "DW_CFA_expression(reg=%lld, expression=0x%llX, length=%llu)\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; + if (logDwarf) + fprintf(stderr, "DW_CFA_offset_extended_sf(reg=%lld, offset=%lld)\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; + if (logDwarf) + fprintf(stderr, "DW_CFA_def_cfa_sf(reg=%lld, offset=%lld)\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; + if (logDwarf) + fprintf(stderr, "DW_CFA_def_cfa_offset_sf(%d)\n", + results->cfaRegisterOffset); + break; + case DW_CFA_val_offset: + reg = addressSpace.getULEB128(p, instructionsEnd); + offset = (int64_t)addressSpace.getULEB128(p, instructionsEnd) + * cieInfo.dataAlignFactor; + results->savedRegisters[reg].location = kRegisterOffsetFromCFA; + results->savedRegisters[reg].value = offset; + if (logDwarf) + fprintf(stderr, "DW_CFA_val_offset(reg=%lld, offset=%lld\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; + if (logDwarf) + fprintf(stderr, "DW_CFA_val_offset_sf(reg=%lld, offset=%lld\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); + p += length; + if (logDwarf) + fprintf( + stderr, + "DW_CFA_val_expression(reg=%lld, expression=0x%llX, length=%lld)\n", + reg, results->savedRegisters[reg].value, length); + break; + case DW_CFA_GNU_args_size: + length = addressSpace.getULEB128(p, instructionsEnd); + results->spExtraArgSize = (uint32_t)length; + if (logDwarf) + fprintf(stderr, "DW_CFA_GNU_args_size(%lld)\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; + if (logDwarf) + fprintf(stderr, "DW_CFA_GNU_negative_offset_extended(%lld)\n", offset); + break; + default: + operand = opcode & 0x3F; + switch (opcode & 0xC0) { + case DW_CFA_offset: + reg = operand; + offset = (int64_t)addressSpace.getULEB128(p, instructionsEnd) + * cieInfo.dataAlignFactor; + results->savedRegisters[reg].location = kRegisterInCFA; + results->savedRegisters[reg].value = offset; + if (logDwarf) + fprintf(stderr, "DW_CFA_offset(reg=%d, offset=%lld)\n", operand, + offset); + break; + case DW_CFA_advance_loc: + codeOffset += operand * cieInfo.codeAlignFactor; + if (logDwarf) + fprintf(stderr, "DW_CFA_advance_loc: new offset=%llu\n", + (uint64_t)codeOffset); + break; + case DW_CFA_restore: + reg = operand; + results->savedRegisters[reg] = initialState.savedRegisters[reg]; + if (logDwarf) + fprintf(stderr, "DW_CFA_restore(reg=%lld)\n", reg); + break; + default: + if (logDwarf) + fprintf(stderr, "unknown CFA opcode 0x%02X\n", opcode); + return false; + } + } + } + + return true; +} + +} // namespace libunwind + +#endif // __DWARF_PARSER_HPP__ |