GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libcxxabi/../libunwind/src/UnwindLevel1-gcc-ext.c Lines: 0 72 0.0 %
Date: 2017-11-13 Branches: 0 52 0.0 %

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//===--------------------- UnwindLevel1-gcc-ext.c -------------------------===//
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//
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//                     The LLVM Compiler Infrastructure
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//
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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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//
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//
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//  Implements gcc extensions to the C++ ABI Exception Handling Level 1.
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//
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//===----------------------------------------------------------------------===//
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#include <inttypes.h>
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#include <stdbool.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "config.h"
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#include "libunwind_ext.h"
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#include "libunwind.h"
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#include "Unwind-EHABI.h"
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#include "unwind.h"
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#if _LIBUNWIND_BUILD_ZERO_COST_APIS
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///  Called by __cxa_rethrow().
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_LIBUNWIND_EXPORT _Unwind_Reason_Code
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_Unwind_Resume_or_Rethrow(_Unwind_Exception *exception_object) {
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#if _LIBUNWIND_ARM_EHABI
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  _LIBUNWIND_TRACE_API("_Unwind_Resume_or_Rethrow(ex_obj=%p), private_1=%ld\n",
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                       (void *)exception_object,
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                       (long)exception_object->unwinder_cache.reserved1);
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#else
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  _LIBUNWIND_TRACE_API("_Unwind_Resume_or_Rethrow(ex_obj=%p), private_1=%ld\n",
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                       (void *)exception_object,
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                       (long)exception_object->private_1);
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#endif
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#if _LIBUNWIND_ARM_EHABI
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  // _Unwind_RaiseException on EHABI will always set the reserved1 field to 0,
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  // which is in the same position as private_1 below.
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  return _Unwind_RaiseException(exception_object);
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#else
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  // If this is non-forced and a stopping place was found, then this is a
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  // re-throw.
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  // Call _Unwind_RaiseException() as if this was a new exception
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  if (exception_object->private_1 == 0) {
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    return _Unwind_RaiseException(exception_object);
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    // Will return if there is no catch clause, so that __cxa_rethrow can call
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    // std::terminate().
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  }
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  // Call through to _Unwind_Resume() which distiguishes between forced and
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  // regular exceptions.
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  _Unwind_Resume(exception_object);
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  _LIBUNWIND_ABORT("_Unwind_Resume_or_Rethrow() called _Unwind_RaiseException()"
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                   " which unexpectedly returned");
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#endif
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}
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/// Called by personality handler during phase 2 to get base address for data
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/// relative encodings.
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_LIBUNWIND_EXPORT uintptr_t
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_Unwind_GetDataRelBase(struct _Unwind_Context *context) {
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  (void)context;
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  _LIBUNWIND_TRACE_API("_Unwind_GetDataRelBase(context=%p)\n", (void *)context);
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  _LIBUNWIND_ABORT("_Unwind_GetDataRelBase() not implemented");
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}
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/// Called by personality handler during phase 2 to get base address for text
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/// relative encodings.
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_LIBUNWIND_EXPORT uintptr_t
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_Unwind_GetTextRelBase(struct _Unwind_Context *context) {
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  (void)context;
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  _LIBUNWIND_TRACE_API("_Unwind_GetTextRelBase(context=%p)\n", (void *)context);
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  _LIBUNWIND_ABORT("_Unwind_GetTextRelBase() not implemented");
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}
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/// Scans unwind information to find the function that contains the
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/// specified code address "pc".
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_LIBUNWIND_EXPORT void *_Unwind_FindEnclosingFunction(void *pc) {
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  _LIBUNWIND_TRACE_API("_Unwind_FindEnclosingFunction(pc=%p)\n", pc);
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  // This is slow, but works.
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  // We create an unwind cursor then alter the IP to be pc
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  unw_cursor_t cursor;
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  unw_context_t uc;
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  unw_proc_info_t info;
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  unw_getcontext(&uc);
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  unw_init_local(&cursor, &uc);
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  unw_set_reg(&cursor, UNW_REG_IP, (unw_word_t)(long) pc);
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  if (unw_get_proc_info(&cursor, &info) == UNW_ESUCCESS)
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    return (void *)(long) info.start_ip;
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  else
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    return NULL;
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}
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/// Walk every frame and call trace function at each one.  If trace function
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/// returns anything other than _URC_NO_REASON, then walk is terminated.
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_LIBUNWIND_EXPORT _Unwind_Reason_Code
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_Unwind_Backtrace(_Unwind_Trace_Fn callback, void *ref) {
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  unw_cursor_t cursor;
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  unw_context_t uc;
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  unw_getcontext(&uc);
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  unw_init_local(&cursor, &uc);
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  _LIBUNWIND_TRACE_API("_Unwind_Backtrace(callback=%p)\n",
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                       (void *)(uintptr_t)callback);
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#if _LIBUNWIND_ARM_EHABI
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  // Create a mock exception object for force unwinding.
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  _Unwind_Exception ex;
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  memset(&ex, '\0', sizeof(ex));
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  ex.exception_class = 0x434C4E47554E5700; // CLNGUNW\0
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#endif
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  // walk each frame
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  while (true) {
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    _Unwind_Reason_Code result;
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#if !_LIBUNWIND_ARM_EHABI
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    // ask libuwind to get next frame (skip over first frame which is
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    // _Unwind_Backtrace())
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    if (unw_step(&cursor) <= 0) {
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      _LIBUNWIND_TRACE_UNWINDING(" _backtrace: ended because cursor reached "
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                                 "bottom of stack, returning %d\n",
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                                 _URC_END_OF_STACK);
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      return _URC_END_OF_STACK;
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    }
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#else
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    // Get the information for this frame.
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    unw_proc_info_t frameInfo;
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    if (unw_get_proc_info(&cursor, &frameInfo) != UNW_ESUCCESS) {
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      return _URC_END_OF_STACK;
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    }
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    // Update the pr_cache in the mock exception object.
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    const uint32_t* unwindInfo = (uint32_t *) frameInfo.unwind_info;
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    ex.pr_cache.fnstart = frameInfo.start_ip;
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    ex.pr_cache.ehtp = (_Unwind_EHT_Header *) unwindInfo;
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    ex.pr_cache.additional= frameInfo.flags;
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    struct _Unwind_Context *context = (struct _Unwind_Context *)&cursor;
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    // Get and call the personality function to unwind the frame.
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    __personality_routine handler = (__personality_routine) frameInfo.handler;
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    if (handler == NULL) {
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      return _URC_END_OF_STACK;
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    }
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    if (handler(_US_VIRTUAL_UNWIND_FRAME | _US_FORCE_UNWIND, &ex, context) !=
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            _URC_CONTINUE_UNWIND) {
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      return _URC_END_OF_STACK;
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    }
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#endif // _LIBUNWIND_ARM_EHABI
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    // debugging
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    if (_LIBUNWIND_TRACING_UNWINDING) {
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      char functionName[512];
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      unw_proc_info_t frame;
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      unw_word_t offset;
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      unw_get_proc_name(&cursor, functionName, 512, &offset);
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      unw_get_proc_info(&cursor, &frame);
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      _LIBUNWIND_TRACE_UNWINDING(
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          " _backtrace: start_ip=0x%llX, func=%s, lsda=0x%llX, context=%p\n",
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          (long long)frame.start_ip, functionName, (long long)frame.lsda,
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          (void *)&cursor);
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    }
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    // call trace function with this frame
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    result = (*callback)((struct _Unwind_Context *)(&cursor), ref);
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    if (result != _URC_NO_REASON) {
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      _LIBUNWIND_TRACE_UNWINDING(
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          " _backtrace: ended because callback returned %d\n", result);
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      return result;
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    }
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  }
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}
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/// Find dwarf unwind info for an address 'pc' in some function.
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_LIBUNWIND_EXPORT const void *_Unwind_Find_FDE(const void *pc,
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                                               struct dwarf_eh_bases *bases) {
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  // This is slow, but works.
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  // We create an unwind cursor then alter the IP to be pc
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  unw_cursor_t cursor;
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  unw_context_t uc;
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  unw_proc_info_t info;
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  unw_getcontext(&uc);
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  unw_init_local(&cursor, &uc);
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  unw_set_reg(&cursor, UNW_REG_IP, (unw_word_t)(long) pc);
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  unw_get_proc_info(&cursor, &info);
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  bases->tbase = (uintptr_t)info.extra;
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  bases->dbase = 0; // dbase not used on Mac OS X
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  bases->func = (uintptr_t)info.start_ip;
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  _LIBUNWIND_TRACE_API("_Unwind_Find_FDE(pc=%p) => %p\n", pc,
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                  (void *)(long) info.unwind_info);
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  return (void *)(long) info.unwind_info;
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}
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/// Returns the CFA (call frame area, or stack pointer at start of function)
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/// for the current context.
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_LIBUNWIND_EXPORT uintptr_t _Unwind_GetCFA(struct _Unwind_Context *context) {
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  unw_cursor_t *cursor = (unw_cursor_t *)context;
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  unw_word_t result;
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  unw_get_reg(cursor, UNW_REG_SP, &result);
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  _LIBUNWIND_TRACE_API("_Unwind_GetCFA(context=%p) => 0x%" PRIx64 "\n",
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                       (void *)context, (uint64_t)result);
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  return (uintptr_t)result;
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}
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/// Called by personality handler during phase 2 to get instruction pointer.
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/// ipBefore is a boolean that says if IP is already adjusted to be the call
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/// site address.  Normally IP is the return address.
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_LIBUNWIND_EXPORT uintptr_t _Unwind_GetIPInfo(struct _Unwind_Context *context,
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                                              int *ipBefore) {
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  _LIBUNWIND_TRACE_API("_Unwind_GetIPInfo(context=%p)\n", (void *)context);
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  *ipBefore = 0;
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  return _Unwind_GetIP(context);
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}
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#if _LIBUNWIND_SUPPORT_DWARF_UNWIND
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/// Called by programs with dynamic code generators that want
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/// to register a dynamically generated FDE.
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/// This function has existed on Mac OS X since 10.4, but
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/// was broken until 10.6.
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_LIBUNWIND_EXPORT void __register_frame(const void *fde) {
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  _LIBUNWIND_TRACE_API("__register_frame(%p)\n", fde);
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  _unw_add_dynamic_fde((unw_word_t)(uintptr_t) fde);
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}
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/// Called by programs with dynamic code generators that want
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/// to unregister a dynamically generated FDE.
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/// This function has existed on Mac OS X since 10.4, but
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/// was broken until 10.6.
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_LIBUNWIND_EXPORT void __deregister_frame(const void *fde) {
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  _LIBUNWIND_TRACE_API("__deregister_frame(%p)\n", fde);
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  _unw_remove_dynamic_fde((unw_word_t)(uintptr_t) fde);
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}
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// The following register/deregister functions are gcc extensions.
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// They have existed on Mac OS X, but have never worked because Mac OS X
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// before 10.6 used keymgr to track known FDEs, but these functions
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// never got updated to use keymgr.
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// For now, we implement these as do-nothing functions to keep any existing
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// applications working.  We also add the not in 10.6 symbol so that nwe
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// application won't be able to use them.
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#if _LIBUNWIND_SUPPORT_FRAME_APIS
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_LIBUNWIND_EXPORT void __register_frame_info_bases(const void *fde, void *ob,
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                                                   void *tb, void *db) {
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  (void)fde;
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  (void)ob;
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  (void)tb;
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  (void)db;
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 _LIBUNWIND_TRACE_API("__register_frame_info_bases(%p,%p, %p, %p)\n",
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                            fde, ob, tb, db);
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  // do nothing, this function never worked in Mac OS X
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}
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_LIBUNWIND_EXPORT void __register_frame_info(const void *fde, void *ob) {
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  (void)fde;
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  (void)ob;
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  _LIBUNWIND_TRACE_API("__register_frame_info(%p, %p)\n", fde, ob);
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  // do nothing, this function never worked in Mac OS X
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}
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_LIBUNWIND_EXPORT void __register_frame_info_table_bases(const void *fde,
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                                                         void *ob, void *tb,
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                                                         void *db) {
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  (void)fde;
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  (void)ob;
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  (void)tb;
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  (void)db;
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  _LIBUNWIND_TRACE_API("__register_frame_info_table_bases"
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                             "(%p,%p, %p, %p)\n", fde, ob, tb, db);
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  // do nothing, this function never worked in Mac OS X
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}
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_LIBUNWIND_EXPORT void __register_frame_info_table(const void *fde, void *ob) {
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  (void)fde;
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  (void)ob;
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  _LIBUNWIND_TRACE_API("__register_frame_info_table(%p, %p)\n", fde, ob);
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  // do nothing, this function never worked in Mac OS X
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}
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_LIBUNWIND_EXPORT void __register_frame_table(const void *fde) {
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  (void)fde;
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  _LIBUNWIND_TRACE_API("__register_frame_table(%p)\n", fde);
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  // do nothing, this function never worked in Mac OS X
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}
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_LIBUNWIND_EXPORT void *__deregister_frame_info(const void *fde) {
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  (void)fde;
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  _LIBUNWIND_TRACE_API("__deregister_frame_info(%p)\n", fde);
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  // do nothing, this function never worked in Mac OS X
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  return NULL;
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}
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_LIBUNWIND_EXPORT void *__deregister_frame_info_bases(const void *fde) {
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  (void)fde;
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  _LIBUNWIND_TRACE_API("__deregister_frame_info_bases(%p)\n", fde);
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  // do nothing, this function never worked in Mac OS X
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  return NULL;
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}
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#endif // _LIBUNWIND_SUPPORT_FRAME_APIS
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#endif // _LIBUNWIND_SUPPORT_DWARF_UNWIND
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#endif // _LIBUNWIND_BUILD_ZERO_COST_APIS