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//===--------------------------- libuwind.cpp -----------------------------===//
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// The LLVM Compiler Infrastructure
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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// Implements unw_* functions from <libunwind.h>
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//===----------------------------------------------------------------------===//
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#include <libunwind.h>
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#include "libunwind_ext.h"
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#if _LIBUNWIND_BUILD_ZERO_COST_APIS
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#include "UnwindCursor.hpp"
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using namespace libunwind;
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/// internal object to represent this processes address space
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LocalAddressSpace LocalAddressSpace::sThisAddressSpace;
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/// record the registers and stack position of the caller
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extern int unw_getcontext(unw_context_t *);
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// note: unw_getcontext() implemented in assembly
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/// Create a cursor of a thread in this process given 'context' recorded by
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_LIBUNWIND_EXPORT int unw_init_local(unw_cursor_t *cursor,
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unw_context_t *context) {
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_LIBUNWIND_TRACE_API("unw_init_local(cursor=%p, context=%p)\n",
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// Use "placement new" to allocate UnwindCursor in the cursor buffer.
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new ((void *)cursor) UnwindCursor<LocalAddressSpace, Registers_x86>(
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context, LocalAddressSpace::sThisAddressSpace);
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new ((void *)cursor) UnwindCursor<LocalAddressSpace, Registers_x86_64>(
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context, LocalAddressSpace::sThisAddressSpace);
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new ((void *)cursor) UnwindCursor<LocalAddressSpace, Registers_ppc>(
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context, LocalAddressSpace::sThisAddressSpace);
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new ((void *)cursor) UnwindCursor<LocalAddressSpace, Registers_arm64>(
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context, LocalAddressSpace::sThisAddressSpace);
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AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
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co->setInfoBasedOnIPRegister();
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_LIBUNWIND_EXPORT unw_addr_space_t unw_local_addr_space =
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(unw_addr_space_t) & sThisAddressSpace;
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/// Create a cursor into a thread in another process.
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_LIBUNWIND_EXPORT int unw_init_remote_thread(unw_cursor_t *cursor,
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// special case: unw_init_remote(xx, unw_local_addr_space, xx)
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if (as == (unw_addr_space_t) & sThisAddressSpace)
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return unw_init_local(cursor, NULL); //FIXME
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// use "placement new" to allocate UnwindCursor in the cursor buffer
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switch (as->cpuType) {
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UnwindCursor<OtherAddressSpace<Pointer32<LittleEndian> >,
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Registers_x86>(((unw_addr_space_i386 *)as)->oas, arg);
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new ((void *)cursor) UnwindCursor<
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OtherAddressSpace<Pointer64<LittleEndian> >, Registers_x86_64>(
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((unw_addr_space_x86_64 *)as)->oas, arg);
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case CPU_TYPE_POWERPC:
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UnwindCursor<OtherAddressSpace<Pointer32<BigEndian> >, Registers_ppc>(
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((unw_addr_space_ppc *)as)->oas, arg);
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static bool is64bit(task_t task) {
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return false; // FIXME
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/// Create an address_space object for use in examining another task.
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_LIBUNWIND_EXPORT unw_addr_space_t unw_create_addr_space_for_task(task_t task) {
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unw_addr_space_x86_64 *as = new unw_addr_space_x86_64(task);
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as->cpuType = CPU_TYPE_X86_64;
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unw_addr_space_i386 *as = new unw_addr_space_i386(task);
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as->cpuType = CPU_TYPE_I386;
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/// Delete an address_space object.
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_LIBUNWIND_EXPORT void unw_destroy_addr_space(unw_addr_space_t asp) {
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switch (asp->cpuType) {
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#if __i386__ || __x86_64__
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case CPU_TYPE_I386: {
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unw_addr_space_i386 *as = (unw_addr_space_i386 *)asp;
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case CPU_TYPE_X86_64: {
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unw_addr_space_x86_64 *as = (unw_addr_space_x86_64 *)asp;
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case CPU_TYPE_POWERPC: {
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unw_addr_space_ppc *as = (unw_addr_space_ppc *)asp;
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/// Get value of specified register at cursor position in stack frame.
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_LIBUNWIND_EXPORT int unw_get_reg(unw_cursor_t *cursor, unw_regnum_t regNum,
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_LIBUNWIND_TRACE_API("unw_get_reg(cursor=%p, regNum=%d, &value=%p)\n",
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cursor, regNum, value);
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AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
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if (co->validReg(regNum)) {
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*value = co->getReg(regNum);
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/// Set value of specified register at cursor position in stack frame.
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_LIBUNWIND_EXPORT int unw_set_reg(unw_cursor_t *cursor, unw_regnum_t regNum,
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_LIBUNWIND_TRACE_API("unw_set_reg(cursor=%p, regNum=%d, value=0x%llX)\n",
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cursor, regNum, value);
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typedef LocalAddressSpace::pint_t pint_t;
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AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
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if (co->validReg(regNum)) {
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co->setReg(regNum, (pint_t)value);
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// specical case altering IP to re-find info (being called by personality
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if (regNum == UNW_REG_IP) {
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unw_proc_info_t info;
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pint_t orgArgSize = (pint_t)info.gp;
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uint64_t orgFuncStart = info.start_ip;
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co->setInfoBasedOnIPRegister(false);
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// and adjust REG_SP if there was a DW_CFA_GNU_args_size
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if ((orgFuncStart == info.start_ip) && (orgArgSize != 0))
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co->setReg(UNW_REG_SP, co->getReg(UNW_REG_SP) + orgArgSize);
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/// Get value of specified float register at cursor position in stack frame.
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_LIBUNWIND_EXPORT int unw_get_fpreg(unw_cursor_t *cursor, unw_regnum_t regNum,
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unw_fpreg_t *value) {
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_LIBUNWIND_TRACE_API("unw_get_fpreg(cursor=%p, regNum=%d, &value=%p)\n",
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cursor, regNum, value);
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AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
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if (co->validFloatReg(regNum)) {
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*value = co->getFloatReg(regNum);
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/// Set value of specified float register at cursor position in stack frame.
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_LIBUNWIND_EXPORT int unw_set_fpreg(unw_cursor_t *cursor, unw_regnum_t regNum,
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_LIBUNWIND_TRACE_API("unw_set_fpreg(cursor=%p, regNum=%d, value=%g)\n",
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cursor, regNum, value);
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AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
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if (co->validFloatReg(regNum)) {
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co->setFloatReg(regNum, value);
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/// Move cursor to next frame.
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_LIBUNWIND_EXPORT int unw_step(unw_cursor_t *cursor) {
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_LIBUNWIND_TRACE_API("unw_step(cursor=%p)\n", cursor);
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AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
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/// Get unwind info at cursor position in stack frame.
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_LIBUNWIND_EXPORT int unw_get_proc_info(unw_cursor_t *cursor,
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unw_proc_info_t *info) {
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_LIBUNWIND_TRACE_API("unw_get_proc_info(cursor=%p, &info=%p)\n",
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AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
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if (info->end_ip == 0)
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/// Resume execution at cursor position (aka longjump).
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_LIBUNWIND_EXPORT int unw_resume(unw_cursor_t *cursor) {
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_LIBUNWIND_TRACE_API("unw_resume(cursor=%p)\n", cursor);
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AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
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/// Get name of function at cursor position in stack frame.
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_LIBUNWIND_EXPORT int unw_get_proc_name(unw_cursor_t *cursor, char *buf,
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size_t bufLen, unw_word_t *offset) {
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_LIBUNWIND_TRACE_API("unw_get_proc_name(cursor=%p, &buf=%p,"
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"bufLen=%ld)\n", cursor, buf, bufLen);
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AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
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if (co->getFunctionName(buf, bufLen, offset))
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/// Checks if a register is a floating-point register.
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_LIBUNWIND_EXPORT int unw_is_fpreg(unw_cursor_t *cursor, unw_regnum_t regNum) {
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_LIBUNWIND_TRACE_API("unw_is_fpreg(cursor=%p, regNum=%d)\n",
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AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
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return co->validFloatReg(regNum);
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/// Checks if a register is a floating-point register.
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_LIBUNWIND_EXPORT const char *unw_regname(unw_cursor_t *cursor,
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unw_regnum_t regNum) {
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_LIBUNWIND_TRACE_API("unw_regname(cursor=%p, regNum=%d)\n",
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AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
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return co->getRegisterName(regNum);
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/// Checks if current frame is signal trampoline.
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_LIBUNWIND_EXPORT int unw_is_signal_frame(unw_cursor_t *cursor) {
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_LIBUNWIND_TRACE_API("unw_is_signal_frame(cursor=%p)\n", cursor);
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AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
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return co->isSignalFrame();
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#if _LIBUNWIND_SUPPORT_DWARF_UNWIND
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/// SPI: walks cached dwarf entries
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_LIBUNWIND_EXPORT void unw_iterate_dwarf_unwind_cache(void (*func)(
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unw_word_t ip_start, unw_word_t ip_end, unw_word_t fde, unw_word_t mh)) {
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_LIBUNWIND_TRACE_API("unw_iterate_dwarf_unwind_cache(func=%p)\n", func);
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DwarfFDECache<LocalAddressSpace>::iterateCacheEntries(func);
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/// IPI: for __register_frame()
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void _unw_add_dynamic_fde(unw_word_t fde) {
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CFI_Parser<LocalAddressSpace>::FDE_Info fdeInfo;
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CFI_Parser<LocalAddressSpace>::CIE_Info cieInfo;
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const char *message = CFI_Parser<LocalAddressSpace>::decodeFDE(
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LocalAddressSpace::sThisAddressSpace,
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(LocalAddressSpace::pint_t) fde, &fdeInfo, &cieInfo);
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if (message == NULL) {
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// dynamically registered FDEs don't have a mach_header group they are in.
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// Use fde as mh_group
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unw_word_t mh_group = fdeInfo.fdeStart;
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DwarfFDECache<LocalAddressSpace>::add((LocalAddressSpace::pint_t)mh_group,
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fdeInfo.pcStart, fdeInfo.pcEnd,
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_LIBUNWIND_DEBUG_LOG("_unw_add_dynamic_fde: bad fde: %s", message);
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/// IPI: for __deregister_frame()
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void _unw_remove_dynamic_fde(unw_word_t fde) {
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// fde is own mh_group
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DwarfFDECache<LocalAddressSpace>::removeAllIn((LocalAddressSpace::pint_t)fde);
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#endif // _LIBUNWIND_SUPPORT_DWARF_UNWIND
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#endif // _LIBUNWIND_BUILD_ZERO_COST_APIS
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// Add logging hooks in Debug builds only
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// do manual lock to avoid use of _cxa_guard_acquire or initializers
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static bool checked = false;
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static bool log = false;
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log = (getenv("LIBUNWIND_PRINT_APIS") != NULL);
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bool logUnwinding() {
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// do manual lock to avoid use of _cxa_guard_acquire or initializers
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static bool checked = false;
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static bool log = false;
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log = (getenv("LIBUNWIND_PRINT_UNWINDING") != NULL);