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Posted to commits@marmotta.apache.org by ja...@apache.org on 2018/06/18 18:35:57 UTC

[38/62] [abbrv] [partial] marmotta git commit: * Replace gtest with upstream version, including LICENSE header. * Include absl library for faster and safer string operations. * Update license headers where needed. * Removed custom code replaced by absl.

http://git-wip-us.apache.org/repos/asf/marmotta/blob/0eb556da/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/elf_mem_image.cc
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diff --git a/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/elf_mem_image.cc b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/elf_mem_image.cc
new file mode 100644
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--- /dev/null
+++ b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/elf_mem_image.cc
@@ -0,0 +1,398 @@
+// Copyright 2017 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Allow dynamic symbol lookup in an in-memory Elf image.
+//
+
+#include "absl/debugging/internal/elf_mem_image.h"
+
+#ifdef ABSL_HAVE_ELF_MEM_IMAGE  // defined in elf_mem_image.h
+
+#include <string.h>
+#include <cassert>
+#include <cstddef>
+#include "absl/base/internal/raw_logging.h"
+
+// From binutils/include/elf/common.h (this doesn't appear to be documented
+// anywhere else).
+//
+//   /* This flag appears in a Versym structure.  It means that the symbol
+//      is hidden, and is only visible with an explicit version number.
+//      This is a GNU extension.  */
+//   #define VERSYM_HIDDEN           0x8000
+//
+//   /* This is the mask for the rest of the Versym information.  */
+//   #define VERSYM_VERSION          0x7fff
+
+#define VERSYM_VERSION 0x7fff
+
+namespace absl {
+namespace debugging_internal {
+
+namespace {
+
+#if __WORDSIZE == 32
+const int kElfClass = ELFCLASS32;
+int ElfBind(const ElfW(Sym) *symbol) { return ELF32_ST_BIND(symbol->st_info); }
+int ElfType(const ElfW(Sym) *symbol) { return ELF32_ST_TYPE(symbol->st_info); }
+#elif __WORDSIZE == 64
+const int kElfClass = ELFCLASS64;
+int ElfBind(const ElfW(Sym) *symbol) { return ELF64_ST_BIND(symbol->st_info); }
+int ElfType(const ElfW(Sym) *symbol) { return ELF64_ST_TYPE(symbol->st_info); }
+#else
+const int kElfClass = -1;
+int ElfBind(const ElfW(Sym) *) {
+  ABSL_RAW_LOG(FATAL, "Unexpected word size");
+  return 0;
+}
+int ElfType(const ElfW(Sym) *) {
+  ABSL_RAW_LOG(FATAL, "Unexpected word size");
+  return 0;
+}
+#endif
+
+// Extract an element from one of the ELF tables, cast it to desired type.
+// This is just a simple arithmetic and a glorified cast.
+// Callers are responsible for bounds checking.
+template <typename T>
+const T *GetTableElement(const ElfW(Ehdr) * ehdr, ElfW(Off) table_offset,
+                         ElfW(Word) element_size, size_t index) {
+  return reinterpret_cast<const T*>(reinterpret_cast<const char *>(ehdr)
+                                    + table_offset
+                                    + index * element_size);
+}
+
+}  // namespace
+
+// The value of this variable doesn't matter; it's used only for its
+// unique address.
+const int ElfMemImage::kInvalidBaseSentinel = 0;
+
+ElfMemImage::ElfMemImage(const void *base) {
+  ABSL_RAW_CHECK(base != kInvalidBase, "bad pointer");
+  Init(base);
+}
+
+int ElfMemImage::GetNumSymbols() const {
+  if (!hash_) {
+    return 0;
+  }
+  // See http://www.caldera.com/developers/gabi/latest/ch5.dynamic.html#hash
+  return hash_[1];
+}
+
+const ElfW(Sym) *ElfMemImage::GetDynsym(int index) const {
+  ABSL_RAW_CHECK(index < GetNumSymbols(), "index out of range");
+  return dynsym_ + index;
+}
+
+const ElfW(Versym) *ElfMemImage::GetVersym(int index) const {
+  ABSL_RAW_CHECK(index < GetNumSymbols(), "index out of range");
+  return versym_ + index;
+}
+
+const ElfW(Phdr) *ElfMemImage::GetPhdr(int index) const {
+  ABSL_RAW_CHECK(index < ehdr_->e_phnum, "index out of range");
+  return GetTableElement<ElfW(Phdr)>(ehdr_,
+                                     ehdr_->e_phoff,
+                                     ehdr_->e_phentsize,
+                                     index);
+}
+
+const char *ElfMemImage::GetDynstr(ElfW(Word) offset) const {
+  ABSL_RAW_CHECK(offset < strsize_, "offset out of range");
+  return dynstr_ + offset;
+}
+
+const void *ElfMemImage::GetSymAddr(const ElfW(Sym) *sym) const {
+  if (sym->st_shndx == SHN_UNDEF || sym->st_shndx >= SHN_LORESERVE) {
+    // Symbol corresponds to "special" (e.g. SHN_ABS) section.
+    return reinterpret_cast<const void *>(sym->st_value);
+  }
+  ABSL_RAW_CHECK(link_base_ < sym->st_value, "symbol out of range");
+  return GetTableElement<char>(ehdr_, 0, 1, sym->st_value) - link_base_;
+}
+
+const ElfW(Verdef) *ElfMemImage::GetVerdef(int index) const {
+  ABSL_RAW_CHECK(0 <= index && static_cast<size_t>(index) <= verdefnum_,
+                 "index out of range");
+  const ElfW(Verdef) *version_definition = verdef_;
+  while (version_definition->vd_ndx < index && version_definition->vd_next) {
+    const char *const version_definition_as_char =
+        reinterpret_cast<const char *>(version_definition);
+    version_definition =
+        reinterpret_cast<const ElfW(Verdef) *>(version_definition_as_char +
+                                               version_definition->vd_next);
+  }
+  return version_definition->vd_ndx == index ? version_definition : nullptr;
+}
+
+const ElfW(Verdaux) *ElfMemImage::GetVerdefAux(
+    const ElfW(Verdef) *verdef) const {
+  return reinterpret_cast<const ElfW(Verdaux) *>(verdef+1);
+}
+
+const char *ElfMemImage::GetVerstr(ElfW(Word) offset) const {
+  ABSL_RAW_CHECK(offset < strsize_, "offset out of range");
+  return dynstr_ + offset;
+}
+
+void ElfMemImage::Init(const void *base) {
+  ehdr_      = nullptr;
+  dynsym_    = nullptr;
+  dynstr_    = nullptr;
+  versym_    = nullptr;
+  verdef_    = nullptr;
+  hash_      = nullptr;
+  strsize_   = 0;
+  verdefnum_ = 0;
+  link_base_ = ~0L;  // Sentinel: PT_LOAD .p_vaddr can't possibly be this.
+  if (!base) {
+    return;
+  }
+  const intptr_t base_as_uintptr_t = reinterpret_cast<uintptr_t>(base);
+  // Fake VDSO has low bit set.
+  const bool fake_vdso = ((base_as_uintptr_t & 1) != 0);
+  base = reinterpret_cast<const void *>(base_as_uintptr_t & ~1);
+  const char *const base_as_char = reinterpret_cast<const char *>(base);
+  if (base_as_char[EI_MAG0] != ELFMAG0 || base_as_char[EI_MAG1] != ELFMAG1 ||
+      base_as_char[EI_MAG2] != ELFMAG2 || base_as_char[EI_MAG3] != ELFMAG3) {
+    assert(false);
+    return;
+  }
+  int elf_class = base_as_char[EI_CLASS];
+  if (elf_class != kElfClass) {
+    assert(false);
+    return;
+  }
+  switch (base_as_char[EI_DATA]) {
+    case ELFDATA2LSB: {
+      if (__LITTLE_ENDIAN != __BYTE_ORDER) {
+        assert(false);
+        return;
+      }
+      break;
+    }
+    case ELFDATA2MSB: {
+      if (__BIG_ENDIAN != __BYTE_ORDER) {
+        assert(false);
+        return;
+      }
+      break;
+    }
+    default: {
+      assert(false);
+      return;
+    }
+  }
+
+  ehdr_ = reinterpret_cast<const ElfW(Ehdr) *>(base);
+  const ElfW(Phdr) *dynamic_program_header = nullptr;
+  for (int i = 0; i < ehdr_->e_phnum; ++i) {
+    const ElfW(Phdr) *const program_header = GetPhdr(i);
+    switch (program_header->p_type) {
+      case PT_LOAD:
+        if (!~link_base_) {
+          link_base_ = program_header->p_vaddr;
+        }
+        break;
+      case PT_DYNAMIC:
+        dynamic_program_header = program_header;
+        break;
+    }
+  }
+  if (!~link_base_ || !dynamic_program_header) {
+    assert(false);
+    // Mark this image as not present. Can not recur infinitely.
+    Init(nullptr);
+    return;
+  }
+  ptrdiff_t relocation =
+      base_as_char - reinterpret_cast<const char *>(link_base_);
+  ElfW(Dyn) *dynamic_entry =
+      reinterpret_cast<ElfW(Dyn) *>(dynamic_program_header->p_vaddr +
+                                    relocation);
+  for (; dynamic_entry->d_tag != DT_NULL; ++dynamic_entry) {
+    ElfW(Xword) value = dynamic_entry->d_un.d_val;
+    if (fake_vdso) {
+      // A complication: in the real VDSO, dynamic entries are not relocated
+      // (it wasn't loaded by a dynamic loader). But when testing with a
+      // "fake" dlopen()ed vdso library, the loader relocates some (but
+      // not all!) of them before we get here.
+      if (dynamic_entry->d_tag == DT_VERDEF) {
+        // The only dynamic entry (of the ones we care about) libc-2.3.6
+        // loader doesn't relocate.
+        value += relocation;
+      }
+    } else {
+      // Real VDSO. Everything needs to be relocated.
+      value += relocation;
+    }
+    switch (dynamic_entry->d_tag) {
+      case DT_HASH:
+        hash_ = reinterpret_cast<ElfW(Word) *>(value);
+        break;
+      case DT_SYMTAB:
+        dynsym_ = reinterpret_cast<ElfW(Sym) *>(value);
+        break;
+      case DT_STRTAB:
+        dynstr_ = reinterpret_cast<const char *>(value);
+        break;
+      case DT_VERSYM:
+        versym_ = reinterpret_cast<ElfW(Versym) *>(value);
+        break;
+      case DT_VERDEF:
+        verdef_ = reinterpret_cast<ElfW(Verdef) *>(value);
+        break;
+      case DT_VERDEFNUM:
+        verdefnum_ = dynamic_entry->d_un.d_val;
+        break;
+      case DT_STRSZ:
+        strsize_ = dynamic_entry->d_un.d_val;
+        break;
+      default:
+        // Unrecognized entries explicitly ignored.
+        break;
+    }
+  }
+  if (!hash_ || !dynsym_ || !dynstr_ || !versym_ ||
+      !verdef_ || !verdefnum_ || !strsize_) {
+    assert(false);  // invalid VDSO
+    // Mark this image as not present. Can not recur infinitely.
+    Init(nullptr);
+    return;
+  }
+}
+
+bool ElfMemImage::LookupSymbol(const char *name,
+                               const char *version,
+                               int type,
+                               SymbolInfo *info_out) const {
+  for (const SymbolInfo& info : *this) {
+    if (strcmp(info.name, name) == 0 && strcmp(info.version, version) == 0 &&
+        ElfType(info.symbol) == type) {
+      if (info_out) {
+        *info_out = info;
+      }
+      return true;
+    }
+  }
+  return false;
+}
+
+bool ElfMemImage::LookupSymbolByAddress(const void *address,
+                                        SymbolInfo *info_out) const {
+  for (const SymbolInfo& info : *this) {
+    const char *const symbol_start =
+        reinterpret_cast<const char *>(info.address);
+    const char *const symbol_end = symbol_start + info.symbol->st_size;
+    if (symbol_start <= address && address < symbol_end) {
+      if (info_out) {
+        // Client wants to know details for that symbol (the usual case).
+        if (ElfBind(info.symbol) == STB_GLOBAL) {
+          // Strong symbol; just return it.
+          *info_out = info;
+          return true;
+        } else {
+          // Weak or local. Record it, but keep looking for a strong one.
+          *info_out = info;
+        }
+      } else {
+        // Client only cares if there is an overlapping symbol.
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+ElfMemImage::SymbolIterator::SymbolIterator(const void *const image, int index)
+    : index_(index), image_(image) {
+}
+
+const ElfMemImage::SymbolInfo *ElfMemImage::SymbolIterator::operator->() const {
+  return &info_;
+}
+
+const ElfMemImage::SymbolInfo& ElfMemImage::SymbolIterator::operator*() const {
+  return info_;
+}
+
+bool ElfMemImage::SymbolIterator::operator==(const SymbolIterator &rhs) const {
+  return this->image_ == rhs.image_ && this->index_ == rhs.index_;
+}
+
+bool ElfMemImage::SymbolIterator::operator!=(const SymbolIterator &rhs) const {
+  return !(*this == rhs);
+}
+
+ElfMemImage::SymbolIterator &ElfMemImage::SymbolIterator::operator++() {
+  this->Update(1);
+  return *this;
+}
+
+ElfMemImage::SymbolIterator ElfMemImage::begin() const {
+  SymbolIterator it(this, 0);
+  it.Update(0);
+  return it;
+}
+
+ElfMemImage::SymbolIterator ElfMemImage::end() const {
+  return SymbolIterator(this, GetNumSymbols());
+}
+
+void ElfMemImage::SymbolIterator::Update(int increment) {
+  const ElfMemImage *image = reinterpret_cast<const ElfMemImage *>(image_);
+  ABSL_RAW_CHECK(image->IsPresent() || increment == 0, "");
+  if (!image->IsPresent()) {
+    return;
+  }
+  index_ += increment;
+  if (index_ >= image->GetNumSymbols()) {
+    index_ = image->GetNumSymbols();
+    return;
+  }
+  const ElfW(Sym)    *symbol = image->GetDynsym(index_);
+  const ElfW(Versym) *version_symbol = image->GetVersym(index_);
+  ABSL_RAW_CHECK(symbol && version_symbol, "");
+  const char *const symbol_name = image->GetDynstr(symbol->st_name);
+  const ElfW(Versym) version_index = version_symbol[0] & VERSYM_VERSION;
+  const ElfW(Verdef) *version_definition = nullptr;
+  const char *version_name = "";
+  if (symbol->st_shndx == SHN_UNDEF) {
+    // Undefined symbols reference DT_VERNEED, not DT_VERDEF, and
+    // version_index could well be greater than verdefnum_, so calling
+    // GetVerdef(version_index) may trigger assertion.
+  } else {
+    version_definition = image->GetVerdef(version_index);
+  }
+  if (version_definition) {
+    // I am expecting 1 or 2 auxiliary entries: 1 for the version itself,
+    // optional 2nd if the version has a parent.
+    ABSL_RAW_CHECK(
+        version_definition->vd_cnt == 1 || version_definition->vd_cnt == 2,
+        "wrong number of entries");
+    const ElfW(Verdaux) *version_aux = image->GetVerdefAux(version_definition);
+    version_name = image->GetVerstr(version_aux->vda_name);
+  }
+  info_.name    = symbol_name;
+  info_.version = version_name;
+  info_.address = image->GetSymAddr(symbol);
+  info_.symbol  = symbol;
+}
+
+}  // namespace debugging_internal
+}  // namespace absl
+
+#endif  // ABSL_HAVE_ELF_MEM_IMAGE

http://git-wip-us.apache.org/repos/asf/marmotta/blob/0eb556da/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/elf_mem_image.h
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diff --git a/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/elf_mem_image.h b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/elf_mem_image.h
new file mode 100644
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--- /dev/null
+++ b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/elf_mem_image.h
@@ -0,0 +1,130 @@
+/*
+ * Copyright 2017 The Abseil Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// Allow dynamic symbol lookup for in-memory Elf images.
+
+#ifndef ABSL_DEBUGGING_INTERNAL_ELF_MEM_IMAGE_H_
+#define ABSL_DEBUGGING_INTERNAL_ELF_MEM_IMAGE_H_
+
+// Including this will define the __GLIBC__ macro if glibc is being
+// used.
+#include <climits>
+
+// Maybe one day we can rewrite this file not to require the elf
+// symbol extensions in glibc, but for right now we need them.
+#ifdef ABSL_HAVE_ELF_MEM_IMAGE
+#error ABSL_HAVE_ELF_MEM_IMAGE cannot be directly set
+#endif
+
+#if defined(__ELF__) && defined(__GLIBC__) && !defined(__native_client__) && \
+    !defined(__asmjs__) && !defined(__wasm__)
+#define ABSL_HAVE_ELF_MEM_IMAGE 1
+#endif
+
+#if ABSL_HAVE_ELF_MEM_IMAGE
+
+#include <link.h>  // for ElfW
+
+namespace absl {
+namespace debugging_internal {
+
+// An in-memory ELF image (may not exist on disk).
+class ElfMemImage {
+ private:
+  // Sentinel: there could never be an elf image at &kInvalidBaseSentinel.
+  static const int kInvalidBaseSentinel;
+
+ public:
+  // Sentinel: there could never be an elf image at this address.
+  static constexpr const void *const kInvalidBase =
+    static_cast<const void*>(&kInvalidBaseSentinel);
+
+  // Information about a single vdso symbol.
+  // All pointers are into .dynsym, .dynstr, or .text of the VDSO.
+  // Do not free() them or modify through them.
+  struct SymbolInfo {
+    const char      *name;      // E.g. "__vdso_getcpu"
+    const char      *version;   // E.g. "LINUX_2.6", could be ""
+                                // for unversioned symbol.
+    const void      *address;   // Relocated symbol address.
+    const ElfW(Sym) *symbol;    // Symbol in the dynamic symbol table.
+  };
+
+  // Supports iteration over all dynamic symbols.
+  class SymbolIterator {
+   public:
+    friend class ElfMemImage;
+    const SymbolInfo *operator->() const;
+    const SymbolInfo &operator*() const;
+    SymbolIterator& operator++();
+    bool operator!=(const SymbolIterator &rhs) const;
+    bool operator==(const SymbolIterator &rhs) const;
+   private:
+    SymbolIterator(const void *const image, int index);
+    void Update(int incr);
+    SymbolInfo info_;
+    int index_;
+    const void *const image_;
+  };
+
+
+  explicit ElfMemImage(const void *base);
+  void                 Init(const void *base);
+  bool                 IsPresent() const { return ehdr_ != nullptr; }
+  const ElfW(Phdr)*    GetPhdr(int index) const;
+  const ElfW(Sym)*     GetDynsym(int index) const;
+  const ElfW(Versym)*  GetVersym(int index) const;
+  const ElfW(Verdef)*  GetVerdef(int index) const;
+  const ElfW(Verdaux)* GetVerdefAux(const ElfW(Verdef) *verdef) const;
+  const char*          GetDynstr(ElfW(Word) offset) const;
+  const void*          GetSymAddr(const ElfW(Sym) *sym) const;
+  const char*          GetVerstr(ElfW(Word) offset) const;
+  int                  GetNumSymbols() const;
+
+  SymbolIterator begin() const;
+  SymbolIterator end() const;
+
+  // Look up versioned dynamic symbol in the image.
+  // Returns false if image is not present, or doesn't contain given
+  // symbol/version/type combination.
+  // If info_out is non-null, additional details are filled in.
+  bool LookupSymbol(const char *name, const char *version,
+                    int symbol_type, SymbolInfo *info_out) const;
+
+  // Find info about symbol (if any) which overlaps given address.
+  // Returns true if symbol was found; false if image isn't present
+  // or doesn't have a symbol overlapping given address.
+  // If info_out is non-null, additional details are filled in.
+  bool LookupSymbolByAddress(const void *address, SymbolInfo *info_out) const;
+
+ private:
+  const ElfW(Ehdr) *ehdr_;
+  const ElfW(Sym) *dynsym_;
+  const ElfW(Versym) *versym_;
+  const ElfW(Verdef) *verdef_;
+  const ElfW(Word) *hash_;
+  const char *dynstr_;
+  size_t strsize_;
+  size_t verdefnum_;
+  ElfW(Addr) link_base_;     // Link-time base (p_vaddr of first PT_LOAD).
+};
+
+}  // namespace debugging_internal
+}  // namespace absl
+
+#endif  // ABSL_HAVE_ELF_MEM_IMAGE
+
+#endif  // ABSL_DEBUGGING_INTERNAL_ELF_MEM_IMAGE_H_

http://git-wip-us.apache.org/repos/asf/marmotta/blob/0eb556da/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/examine_stack.cc
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diff --git a/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/examine_stack.cc b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/examine_stack.cc
new file mode 100644
index 0000000..261daae
--- /dev/null
+++ b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/examine_stack.cc
@@ -0,0 +1,147 @@
+//
+// Copyright 2018 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#include "absl/debugging/internal/examine_stack.h"
+
+#ifndef _WIN32
+#include <unistd.h>
+#endif
+
+#include <csignal>
+#include <cstdio>
+
+#include "absl/base/attributes.h"
+#include "absl/base/internal/raw_logging.h"
+#include "absl/base/macros.h"
+#include "absl/debugging/stacktrace.h"
+#include "absl/debugging/symbolize.h"
+
+namespace absl {
+namespace debugging_internal {
+
+// Returns the program counter from signal context, nullptr if
+// unknown. vuc is a ucontext_t*. We use void* to avoid the use of
+// ucontext_t on non-POSIX systems.
+void* GetProgramCounter(void* vuc) {
+#ifdef __linux__
+  if (vuc != nullptr) {
+    ucontext_t* context = reinterpret_cast<ucontext_t*>(vuc);
+#if defined(__aarch64__)
+    return reinterpret_cast<void*>(context->uc_mcontext.pc);
+#elif defined(__arm__)
+    return reinterpret_cast<void*>(context->uc_mcontext.arm_pc);
+#elif defined(__i386__)
+    if (14 < ABSL_ARRAYSIZE(context->uc_mcontext.gregs))
+      return reinterpret_cast<void*>(context->uc_mcontext.gregs[14]);
+#elif defined(__powerpc64__)
+    return reinterpret_cast<void*>(context->uc_mcontext.gp_regs[32]);
+#elif defined(__powerpc__)
+    return reinterpret_cast<void*>(context->uc_mcontext.regs->nip);
+#elif defined(__x86_64__)
+    if (16 < ABSL_ARRAYSIZE(context->uc_mcontext.gregs))
+      return reinterpret_cast<void*>(context->uc_mcontext.gregs[16]);
+#else
+#error "Undefined Architecture."
+#endif
+  }
+#elif defined(__akaros__)
+  auto* ctx = reinterpret_cast<struct user_context*>(vuc);
+  return reinterpret_cast<void*>(get_user_ctx_pc(ctx));
+#endif
+  static_cast<void>(vuc);
+  return nullptr;
+}
+
+// The %p field width for printf() functions is two characters per byte,
+// and two extra for the leading "0x".
+static constexpr int kPrintfPointerFieldWidth = 2 + 2 * sizeof(void*);
+
+// Print a program counter, its stack frame size, and its symbol name.
+// Note that there is a separate symbolize_pc argument. Return addresses may be
+// at the end of the function, and this allows the caller to back up from pc if
+// appropriate.
+static void DumpPCAndFrameSizeAndSymbol(void (*writerfn)(const char*, void*),
+                                        void* writerfn_arg, void* pc,
+                                        void* symbolize_pc, int framesize,
+                                        const char* const prefix) {
+  char tmp[1024];
+  const char* symbol = "(unknown)";
+  if (absl::Symbolize(symbolize_pc, tmp, sizeof(tmp))) {
+    symbol = tmp;
+  }
+  char buf[1024];
+  if (framesize <= 0) {
+    snprintf(buf, sizeof(buf), "%s@ %*p  (unknown)  %s\n", prefix,
+             kPrintfPointerFieldWidth, pc, symbol);
+  } else {
+    snprintf(buf, sizeof(buf), "%s@ %*p  %9d  %s\n", prefix,
+             kPrintfPointerFieldWidth, pc, framesize, symbol);
+  }
+  writerfn(buf, writerfn_arg);
+}
+
+// Print a program counter and the corresponding stack frame size.
+static void DumpPCAndFrameSize(void (*writerfn)(const char*, void*),
+                               void* writerfn_arg, void* pc, int framesize,
+                               const char* const prefix) {
+  char buf[100];
+  if (framesize <= 0) {
+    snprintf(buf, sizeof(buf), "%s@ %*p  (unknown)\n", prefix,
+             kPrintfPointerFieldWidth, pc);
+  } else {
+    snprintf(buf, sizeof(buf), "%s@ %*p  %9d\n", prefix,
+             kPrintfPointerFieldWidth, pc, framesize);
+  }
+  writerfn(buf, writerfn_arg);
+}
+
+void DumpPCAndFrameSizesAndStackTrace(
+    void* pc, void* const stack[], int frame_sizes[], int depth,
+    int min_dropped_frames, bool symbolize_stacktrace,
+    void (*writerfn)(const char*, void*), void* writerfn_arg) {
+  if (pc != nullptr) {
+    // We don't know the stack frame size for PC, use 0.
+    if (symbolize_stacktrace) {
+      DumpPCAndFrameSizeAndSymbol(writerfn, writerfn_arg, pc, pc, 0, "PC: ");
+    } else {
+      DumpPCAndFrameSize(writerfn, writerfn_arg, pc, 0, "PC: ");
+    }
+  }
+  for (int i = 0; i < depth; i++) {
+    if (symbolize_stacktrace) {
+      // Pass the previous address of pc as the symbol address because pc is a
+      // return address, and an overrun may occur when the function ends with a
+      // call to a function annotated noreturn (e.g. CHECK). Note that we don't
+      // do this for pc above, as the adjustment is only correct for return
+      // addresses.
+      DumpPCAndFrameSizeAndSymbol(writerfn, writerfn_arg, stack[i],
+                                  reinterpret_cast<char*>(stack[i]) - 1,
+                                  frame_sizes[i], "    ");
+    } else {
+      DumpPCAndFrameSize(writerfn, writerfn_arg, stack[i], frame_sizes[i],
+                         "    ");
+    }
+  }
+  if (min_dropped_frames > 0) {
+    char buf[100];
+    snprintf(buf, sizeof(buf), "    @ ... and at least %d more frames\n",
+             min_dropped_frames);
+    writerfn(buf, writerfn_arg);
+  }
+}
+
+}  // namespace debugging_internal
+}  // namespace absl

http://git-wip-us.apache.org/repos/asf/marmotta/blob/0eb556da/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/examine_stack.h
----------------------------------------------------------------------
diff --git a/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/examine_stack.h b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/examine_stack.h
new file mode 100644
index 0000000..a16c03b
--- /dev/null
+++ b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/examine_stack.h
@@ -0,0 +1,38 @@
+//
+// Copyright 2018 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#ifndef ABSL_DEBUGGING_INTERNAL_EXAMINE_STACK_H_
+#define ABSL_DEBUGGING_INTERNAL_EXAMINE_STACK_H_
+
+namespace absl {
+namespace debugging_internal {
+
+// Returns the program counter from signal context, or nullptr if
+// unknown. `vuc` is a ucontext_t*. We use void* to avoid the use of
+// ucontext_t on non-POSIX systems.
+void* GetProgramCounter(void* vuc);
+
+// Uses `writerfn` to dump the program counter, stack trace, and stack
+// frame sizes.
+void DumpPCAndFrameSizesAndStackTrace(
+    void* pc, void* const stack[], int frame_sizes[], int depth,
+    int min_dropped_frames, bool symbolize_stacktrace,
+    void (*writerfn)(const char*, void*), void* writerfn_arg);
+
+}  // namespace debugging_internal
+}  // namespace absl
+
+#endif  // ABSL_DEBUGGING_INTERNAL_EXAMINE_STACK_H_

http://git-wip-us.apache.org/repos/asf/marmotta/blob/0eb556da/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stack_consumption.cc
----------------------------------------------------------------------
diff --git a/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stack_consumption.cc b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stack_consumption.cc
new file mode 100644
index 0000000..2b3b972
--- /dev/null
+++ b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stack_consumption.cc
@@ -0,0 +1,172 @@
+//
+// Copyright 2018 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "absl/debugging/internal/stack_consumption.h"
+
+#ifdef ABSL_INTERNAL_HAVE_DEBUGGING_STACK_CONSUMPTION
+
+#include <signal.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+#include <string.h>
+
+#include "absl/base/attributes.h"
+#include "absl/base/internal/raw_logging.h"
+
+namespace absl {
+namespace debugging_internal {
+namespace {
+
+// This code requires that we know the direction in which the stack
+// grows. It is commonly believed that this can be detected by putting
+// a variable on the stack and then passing its address to a function
+// that compares the address of this variable to the address of a
+// variable on the function's own stack. However, this is unspecified
+// behavior in C++: If two pointers p and q of the same type point to
+// different objects that are not members of the same object or
+// elements of the same array or to different functions, or if only
+// one of them is null, the results of p<q, p>q, p<=q, and p>=q are
+// unspecified. Therefore, instead we hardcode the direction of the
+// stack on platforms we know about.
+#if defined(__i386__) || defined(__x86_64__) || defined(__ppc__)
+constexpr bool kStackGrowsDown = true;
+#else
+#error Need to define kStackGrowsDown
+#endif
+
+// To measure the stack footprint of some code, we create a signal handler
+// (for SIGUSR2 say) that exercises this code on an alternate stack. This
+// alternate stack is initialized to some known pattern (0x55, 0x55, 0x55,
+// ...). We then self-send this signal, and after the signal handler returns,
+// look at the alternate stack buffer to see what portion has been touched.
+//
+// This trick gives us the the stack footprint of the signal handler.  But the
+// signal handler, even before the code for it is exercised, consumes some
+// stack already. We however only want the stack usage of the code inside the
+// signal handler. To measure this accurately, we install two signal handlers:
+// one that does nothing and just returns, and the user-provided signal
+// handler. The difference between the stack consumption of these two signals
+// handlers should give us the stack foorprint of interest.
+
+void EmptySignalHandler(int) {}
+
+// This is arbitrary value, and could be increase further, at the cost of
+// memset()ting it all to known sentinel value.
+constexpr int kAlternateStackSize = 64 << 10;  // 64KiB
+
+constexpr int kSafetyMargin = 32;
+constexpr char kAlternateStackFillValue = 0x55;
+
+// These helper functions look at the alternate stack buffer, and figure
+// out what portion of this buffer has been touched - this is the stack
+// consumption of the signal handler running on this alternate stack.
+// This function will return -1 if the alternate stack buffer has not been
+// touched. It will abort the program if the buffer has overflowed or is about
+// to overflow.
+int GetStackConsumption(const void* const altstack) {
+  const char* begin;
+  int increment;
+  if (kStackGrowsDown) {
+    begin = reinterpret_cast<const char*>(altstack);
+    increment = 1;
+  } else {
+    begin = reinterpret_cast<const char*>(altstack) + kAlternateStackSize - 1;
+    increment = -1;
+  }
+
+  for (int usage_count = kAlternateStackSize; usage_count > 0; --usage_count) {
+    if (*begin != kAlternateStackFillValue) {
+      ABSL_RAW_CHECK(usage_count <= kAlternateStackSize - kSafetyMargin,
+                     "Buffer has overflowed or is about to overflow");
+      return usage_count;
+    }
+    begin += increment;
+  }
+
+  ABSL_RAW_LOG(FATAL, "Unreachable code");
+  return -1;
+}
+
+}  // namespace
+
+int GetSignalHandlerStackConsumption(void (*signal_handler)(int)) {
+  // The alt-signal-stack cannot be heap allocated because there is a
+  // bug in glibc-2.2 where some signal handler setup code looks at the
+  // current stack pointer to figure out what thread is currently running.
+  // Therefore, the alternate stack must be allocated from the main stack
+  // itself.
+  void* altstack = mmap(nullptr, kAlternateStackSize, PROT_READ | PROT_WRITE,
+                        MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+  ABSL_RAW_CHECK(altstack != MAP_FAILED, "mmap() failed");
+
+  // Set up the alt-signal-stack (and save the older one).
+  stack_t sigstk;
+  memset(&sigstk, 0, sizeof(sigstk));
+  stack_t old_sigstk;
+  sigstk.ss_sp = altstack;
+  sigstk.ss_size = kAlternateStackSize;
+  sigstk.ss_flags = 0;
+  ABSL_RAW_CHECK(sigaltstack(&sigstk, &old_sigstk) == 0,
+                 "sigaltstack() failed");
+
+  // Set up SIGUSR1 and SIGUSR2 signal handlers (and save the older ones).
+  struct sigaction sa;
+  memset(&sa, 0, sizeof(sa));
+  struct sigaction old_sa1, old_sa2;
+  sigemptyset(&sa.sa_mask);
+  sa.sa_flags = SA_ONSTACK;
+
+  // SIGUSR1 maps to EmptySignalHandler.
+  sa.sa_handler = EmptySignalHandler;
+  ABSL_RAW_CHECK(sigaction(SIGUSR1, &sa, &old_sa1) == 0, "sigaction() failed");
+
+  // SIGUSR2 maps to signal_handler.
+  sa.sa_handler = signal_handler;
+  ABSL_RAW_CHECK(sigaction(SIGUSR2, &sa, &old_sa2) == 0, "sigaction() failed");
+
+  // Send SIGUSR1 signal and measure the stack consumption of the empty
+  // signal handler.
+  // The first signal might use more stack space. Run once and ignore the
+  // results to get that out of the way.
+  ABSL_RAW_CHECK(kill(getpid(), SIGUSR1) == 0, "kill() failed");
+
+  memset(altstack, kAlternateStackFillValue, kAlternateStackSize);
+  ABSL_RAW_CHECK(kill(getpid(), SIGUSR1) == 0, "kill() failed");
+  int base_stack_consumption = GetStackConsumption(altstack);
+
+  // Send SIGUSR2 signal and measure the stack consumption of signal_handler.
+  ABSL_RAW_CHECK(kill(getpid(), SIGUSR2) == 0, "kill() failed");
+  int signal_handler_stack_consumption = GetStackConsumption(altstack);
+
+  // Now restore the old alt-signal-stack and signal handlers.
+  ABSL_RAW_CHECK(sigaltstack(&old_sigstk, nullptr) == 0,
+                 "sigaltstack() failed");
+  ABSL_RAW_CHECK(sigaction(SIGUSR1, &old_sa1, nullptr) == 0,
+                 "sigaction() failed");
+  ABSL_RAW_CHECK(sigaction(SIGUSR2, &old_sa2, nullptr) == 0,
+                 "sigaction() failed");
+
+  ABSL_RAW_CHECK(munmap(altstack, kAlternateStackSize) == 0, "munmap() failed");
+  if (signal_handler_stack_consumption != -1 && base_stack_consumption != -1) {
+    return signal_handler_stack_consumption - base_stack_consumption;
+  }
+  return -1;
+}
+
+}  // namespace debugging_internal
+}  // namespace absl
+
+#endif  // ABSL_INTERNAL_HAVE_DEBUGGING_STACK_CONSUMPTION

http://git-wip-us.apache.org/repos/asf/marmotta/blob/0eb556da/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stack_consumption.h
----------------------------------------------------------------------
diff --git a/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stack_consumption.h b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stack_consumption.h
new file mode 100644
index 0000000..4c5fa0f
--- /dev/null
+++ b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stack_consumption.h
@@ -0,0 +1,45 @@
+//
+// Copyright 2018 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Helper function for measuring stack consumption of signal handlers.
+
+#ifndef ABSL_DEBUGGING_INTERNAL_STACK_CONSUMPTION_H_
+#define ABSL_DEBUGGING_INTERNAL_STACK_CONSUMPTION_H_
+
+// The code in this module is not portable.
+// Use this feature test macro to detect its availability.
+#ifdef ABSL_INTERNAL_HAVE_DEBUGGING_STACK_CONSUMPTION
+#error ABSL_INTERNAL_HAVE_DEBUGGING_STACK_CONSUMPTION cannot be set directly
+#elif !defined(__APPLE__) && !defined(_WIN32) && \
+    (defined(__i386__) || defined(__x86_64__) || defined(__ppc__))
+#define ABSL_INTERNAL_HAVE_DEBUGGING_STACK_CONSUMPTION 1
+
+namespace absl {
+namespace debugging_internal {
+
+// Returns the stack consumption in bytes for the code exercised by
+// signal_handler.  To measure stack consumption, signal_handler is registered
+// as a signal handler, so the code that it exercises must be async-signal
+// safe.  The argument of signal_handler is an implementation detail of signal
+// handlers and should ignored by the code for signal_handler.  Use global
+// variables to pass information between your test code and signal_handler.
+int GetSignalHandlerStackConsumption(void (*signal_handler)(int));
+
+}  // namespace debugging_internal
+}  // namespace absl
+
+#endif  // ABSL_INTERNAL_HAVE_DEBUGGING_STACK_CONSUMPTION
+
+#endif  // ABSL_DEBUGGING_INTERNAL_STACK_CONSUMPTION_H_

http://git-wip-us.apache.org/repos/asf/marmotta/blob/0eb556da/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stack_consumption_test.cc
----------------------------------------------------------------------
diff --git a/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stack_consumption_test.cc b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stack_consumption_test.cc
new file mode 100644
index 0000000..5ce3846
--- /dev/null
+++ b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stack_consumption_test.cc
@@ -0,0 +1,48 @@
+//
+// Copyright 2018 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "absl/debugging/internal/stack_consumption.h"
+
+#ifdef ABSL_INTERNAL_HAVE_DEBUGGING_STACK_CONSUMPTION
+
+#include <string.h>
+
+#include "gtest/gtest.h"
+#include "absl/base/internal/raw_logging.h"
+
+namespace absl {
+namespace debugging_internal {
+namespace {
+
+static void SimpleSignalHandler(int signo) {
+  char buf[100];
+  memset(buf, 'a', sizeof(buf));
+
+  // Never true, but prevents compiler from optimizing buf out.
+  if (signo == 0) {
+    ABSL_RAW_LOG(INFO, "%p", static_cast<void*>(buf));
+  }
+}
+
+TEST(SignalHandlerStackConsumptionTest, MeasuresStackConsumption) {
+  // Our handler should consume reasonable number of bytes.
+  EXPECT_GE(GetSignalHandlerStackConsumption(SimpleSignalHandler), 100);
+}
+
+}  // namespace
+}  // namespace debugging_internal
+}  // namespace absl
+
+#endif  // ABSL_INTERNAL_HAVE_DEBUGGING_STACK_CONSUMPTION

http://git-wip-us.apache.org/repos/asf/marmotta/blob/0eb556da/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_aarch64-inl.inc
----------------------------------------------------------------------
diff --git a/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_aarch64-inl.inc b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_aarch64-inl.inc
new file mode 100644
index 0000000..a861c0a
--- /dev/null
+++ b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_aarch64-inl.inc
@@ -0,0 +1,189 @@
+#ifndef ABSL_DEBUGGING_INTERNAL_STACKTRACE_AARCH64_INL_H_
+#define ABSL_DEBUGGING_INTERNAL_STACKTRACE_AARCH64_INL_H_
+
+// Generate stack tracer for aarch64
+
+#if defined(__linux__)
+#include <sys/mman.h>
+#include <ucontext.h>
+#include <unistd.h>
+#endif
+
+#include <atomic>
+#include <cassert>
+#include <cstdint>
+#include <iostream>
+
+#include "absl/debugging/internal/address_is_readable.h"
+#include "absl/debugging/internal/vdso_support.h"  // a no-op on non-elf or non-glibc systems
+#include "absl/debugging/stacktrace.h"
+
+static const uintptr_t kUnknownFrameSize = 0;
+
+#if defined(__linux__)
+// Returns the address of the VDSO __kernel_rt_sigreturn function, if present.
+static const unsigned char* GetKernelRtSigreturnAddress() {
+  constexpr uintptr_t kImpossibleAddress = 1;
+  static std::atomic<uintptr_t> memoized{kImpossibleAddress};
+  uintptr_t address = memoized.load(std::memory_order_relaxed);
+  if (address != kImpossibleAddress) {
+    return reinterpret_cast<const unsigned char*>(address);
+  }
+
+  address = reinterpret_cast<uintptr_t>(nullptr);
+
+#ifdef ABSL_HAVE_VDSO_SUPPORT
+  absl::debugging_internal::VDSOSupport vdso;
+  if (vdso.IsPresent()) {
+    absl::debugging_internal::VDSOSupport::SymbolInfo symbol_info;
+    if (!vdso.LookupSymbol("__kernel_rt_sigreturn", "LINUX_2.6.39", STT_FUNC,
+                           &symbol_info) ||
+        symbol_info.address == nullptr) {
+      // Unexpected: VDSO is present, yet the expected symbol is missing
+      // or null.
+      assert(false && "VDSO is present, but doesn't have expected symbol");
+    } else {
+      if (reinterpret_cast<uintptr_t>(symbol_info.address) !=
+          kImpossibleAddress) {
+        address = reinterpret_cast<uintptr_t>(symbol_info.address);
+      } else {
+        assert(false && "VDSO returned invalid address");
+      }
+    }
+  }
+#endif
+
+  memoized.store(address, std::memory_order_relaxed);
+  return reinterpret_cast<const unsigned char*>(address);
+}
+#endif  // __linux__
+
+// Compute the size of a stack frame in [low..high).  We assume that
+// low < high.  Return size of kUnknownFrameSize.
+template<typename T>
+static inline uintptr_t ComputeStackFrameSize(const T* low,
+                                              const T* high) {
+  const char* low_char_ptr = reinterpret_cast<const char *>(low);
+  const char* high_char_ptr = reinterpret_cast<const char *>(high);
+  return low < high ? high_char_ptr - low_char_ptr : kUnknownFrameSize;
+}
+
+// Given a pointer to a stack frame, locate and return the calling
+// stackframe, or return null if no stackframe can be found. Perform sanity
+// checks (the strictness of which is controlled by the boolean parameter
+// "STRICT_UNWINDING") to reduce the chance that a bad pointer is returned.
+template<bool STRICT_UNWINDING, bool WITH_CONTEXT>
+static void **NextStackFrame(void **old_frame_pointer, const void *uc) {
+  void **new_frame_pointer = reinterpret_cast<void**>(*old_frame_pointer);
+  bool check_frame_size = true;
+
+#if defined(__linux__)
+  if (WITH_CONTEXT && uc != nullptr) {
+    // Check to see if next frame's return address is __kernel_rt_sigreturn.
+    if (old_frame_pointer[1] == GetKernelRtSigreturnAddress()) {
+      const ucontext_t *ucv = static_cast<const ucontext_t *>(uc);
+      // old_frame_pointer[0] is not suitable for unwinding, look at
+      // ucontext to discover frame pointer before signal.
+      void **const pre_signal_frame_pointer =
+          reinterpret_cast<void **>(ucv->uc_mcontext.regs[29]);
+
+      // Check that alleged frame pointer is actually readable. This is to
+      // prevent "double fault" in case we hit the first fault due to e.g.
+      // stack corruption.
+      if (!absl::debugging_internal::AddressIsReadable(
+              pre_signal_frame_pointer))
+        return nullptr;
+
+      // Alleged frame pointer is readable, use it for further unwinding.
+      new_frame_pointer = pre_signal_frame_pointer;
+
+      // Skip frame size check if we return from a signal. We may be using a
+      // an alternate stack for signals.
+      check_frame_size = false;
+    }
+  }
+#endif
+
+  // aarch64 ABI requires stack pointer to be 16-byte-aligned.
+  if ((reinterpret_cast<uintptr_t>(new_frame_pointer) & 15) != 0)
+    return nullptr;
+
+  // Check frame size.  In strict mode, we assume frames to be under
+  // 100,000 bytes.  In non-strict mode, we relax the limit to 1MB.
+  if (check_frame_size) {
+    const uintptr_t max_size = STRICT_UNWINDING ? 100000 : 1000000;
+    const uintptr_t frame_size =
+        ComputeStackFrameSize(old_frame_pointer, new_frame_pointer);
+    if (frame_size == kUnknownFrameSize || frame_size > max_size)
+      return nullptr;
+  }
+
+  return new_frame_pointer;
+}
+
+template <bool IS_STACK_FRAMES, bool IS_WITH_CONTEXT>
+static int UnwindImpl(void** result, int* sizes, int max_depth, int skip_count,
+                      const void *ucp, int *min_dropped_frames) {
+#ifdef __GNUC__
+  void **frame_pointer = reinterpret_cast<void**>(__builtin_frame_address(0));
+#else
+# error reading stack point not yet supported on this platform.
+#endif
+
+  skip_count++;    // Skip the frame for this function.
+  int n = 0;
+
+  // The frame pointer points to low address of a frame.  The first 64-bit
+  // word of a frame points to the next frame up the call chain, which normally
+  // is just after the high address of the current frame.  The second word of
+  // a frame contains return adress of to the caller.   To find a pc value
+  // associated with the current frame, we need to go down a level in the call
+  // chain.  So we remember return the address of the last frame seen.  This
+  // does not work for the first stack frame, which belongs to UnwindImp() but
+  // we skip the frame for UnwindImp() anyway.
+  void* prev_return_address = nullptr;
+
+  while (frame_pointer && n < max_depth) {
+    // The absl::GetStackFrames routine is called when we are in some
+    // informational context (the failure signal handler for example).
+    // Use the non-strict unwinding rules to produce a stack trace
+    // that is as complete as possible (even if it contains a few bogus
+    // entries in some rare cases).
+    void **next_frame_pointer =
+        NextStackFrame<!IS_STACK_FRAMES, IS_WITH_CONTEXT>(frame_pointer, ucp);
+
+    if (skip_count > 0) {
+      skip_count--;
+    } else {
+      result[n] = prev_return_address;
+      if (IS_STACK_FRAMES) {
+        sizes[n] = ComputeStackFrameSize(frame_pointer, next_frame_pointer);
+      }
+      n++;
+    }
+    prev_return_address = frame_pointer[1];
+    frame_pointer = next_frame_pointer;
+  }
+  if (min_dropped_frames != nullptr) {
+    // Implementation detail: we clamp the max of frames we are willing to
+    // count, so as not to spend too much time in the loop below.
+    const int kMaxUnwind = 200;
+    int j = 0;
+    for (; frame_pointer != nullptr && j < kMaxUnwind; j++) {
+      frame_pointer =
+          NextStackFrame<!IS_STACK_FRAMES, IS_WITH_CONTEXT>(frame_pointer, ucp);
+    }
+    *min_dropped_frames = j;
+  }
+  return n;
+}
+
+namespace absl {
+namespace debugging_internal {
+bool StackTraceWorksForTest() {
+  return true;
+}
+}  // namespace debugging_internal
+}  // namespace absl
+
+#endif  // ABSL_DEBUGGING_INTERNAL_STACKTRACE_AARCH64_INL_H_

http://git-wip-us.apache.org/repos/asf/marmotta/blob/0eb556da/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_arm-inl.inc
----------------------------------------------------------------------
diff --git a/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_arm-inl.inc b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_arm-inl.inc
new file mode 100644
index 0000000..c840833
--- /dev/null
+++ b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_arm-inl.inc
@@ -0,0 +1,123 @@
+// Copyright 2011 and onwards Google Inc.
+// All rights reserved.
+//
+// Author: Doug Kwan
+// This is inspired by Craig Silverstein's PowerPC stacktrace code.
+//
+
+#ifndef ABSL_DEBUGGING_INTERNAL_STACKTRACE_ARM_INL_H_
+#define ABSL_DEBUGGING_INTERNAL_STACKTRACE_ARM_INL_H_
+
+#include <cstdint>
+
+#include "absl/debugging/stacktrace.h"
+
+// WARNING:
+// This only works if all your code is in either ARM or THUMB mode.  With
+// interworking, the frame pointer of the caller can either be in r11 (ARM
+// mode) or r7 (THUMB mode).  A callee only saves the frame pointer of its
+// mode in a fixed location on its stack frame.  If the caller is a different
+// mode, there is no easy way to find the frame pointer.  It can either be
+// still in the designated register or saved on stack along with other callee
+// saved registers.
+
+// Given a pointer to a stack frame, locate and return the calling
+// stackframe, or return nullptr if no stackframe can be found. Perform sanity
+// checks (the strictness of which is controlled by the boolean parameter
+// "STRICT_UNWINDING") to reduce the chance that a bad pointer is returned.
+template<bool STRICT_UNWINDING>
+static void **NextStackFrame(void **old_sp) {
+  void **new_sp = (void**) old_sp[-1];
+
+  // Check that the transition from frame pointer old_sp to frame
+  // pointer new_sp isn't clearly bogus
+  if (STRICT_UNWINDING) {
+    // With the stack growing downwards, older stack frame must be
+    // at a greater address that the current one.
+    if (new_sp <= old_sp) return nullptr;
+    // Assume stack frames larger than 100,000 bytes are bogus.
+    if ((uintptr_t)new_sp - (uintptr_t)old_sp > 100000) return nullptr;
+  } else {
+    // In the non-strict mode, allow discontiguous stack frames.
+    // (alternate-signal-stacks for example).
+    if (new_sp == old_sp) return nullptr;
+    // And allow frames upto about 1MB.
+    if ((new_sp > old_sp)
+        && ((uintptr_t)new_sp - (uintptr_t)old_sp > 1000000)) return nullptr;
+  }
+  if ((uintptr_t)new_sp & (sizeof(void *) - 1)) return nullptr;
+  return new_sp;
+}
+
+// This ensures that absl::GetStackTrace sets up the Link Register properly.
+#ifdef __GNUC__
+void StacktraceArmDummyFunction() __attribute__((noinline));
+void StacktraceArmDummyFunction() { __asm__ volatile(""); }
+#else
+# error StacktraceArmDummyFunction() needs to be ported to this platform.
+#endif
+
+template <bool IS_STACK_FRAMES, bool IS_WITH_CONTEXT>
+static int UnwindImpl(void** result, int* sizes, int max_depth, int skip_count,
+                      const void * /* ucp */, int *min_dropped_frames) {
+#ifdef __GNUC__
+  void **sp = reinterpret_cast<void**>(__builtin_frame_address(0));
+#else
+# error reading stack point not yet supported on this platform.
+#endif
+
+  // On ARM, the return address is stored in the link register (r14).
+  // This is not saved on the stack frame of a leaf function.  To
+  // simplify code that reads return addresses, we call a dummy
+  // function so that the return address of this function is also
+  // stored in the stack frame.  This works at least for gcc.
+  StacktraceArmDummyFunction();
+
+  int n = 0;
+  while (sp && n < max_depth) {
+    // The absl::GetStackFrames routine is called when we are in some
+    // informational context (the failure signal handler for example).
+    // Use the non-strict unwinding rules to produce a stack trace
+    // that is as complete as possible (even if it contains a few bogus
+    // entries in some rare cases).
+    void **next_sp = NextStackFrame<!IS_STACK_FRAMES>(sp);
+
+    if (skip_count > 0) {
+      skip_count--;
+    } else {
+      result[n] = *sp;
+
+      if (IS_STACK_FRAMES) {
+        if (next_sp > sp) {
+          sizes[n] = (uintptr_t)next_sp - (uintptr_t)sp;
+        } else {
+          // A frame-size of 0 is used to indicate unknown frame size.
+          sizes[n] = 0;
+        }
+      }
+      n++;
+    }
+    sp = next_sp;
+  }
+  if (min_dropped_frames != nullptr) {
+    // Implementation detail: we clamp the max of frames we are willing to
+    // count, so as not to spend too much time in the loop below.
+    const int kMaxUnwind = 200;
+    int j = 0;
+    for (; sp != nullptr && j < kMaxUnwind; j++) {
+      sp = NextStackFrame<!IS_STACK_FRAMES>(sp);
+    }
+    *min_dropped_frames = j;
+  }
+  return n;
+}
+
+namespace absl {
+namespace debugging_internal {
+bool StackTraceWorksForTest() {
+  return false;
+}
+}  // namespace debugging_internal
+}  // namespace absl
+
+#endif  // ABSL_DEBUGGING_INTERNAL_STACKTRACE_ARM_INL_H_

http://git-wip-us.apache.org/repos/asf/marmotta/blob/0eb556da/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_config.h
----------------------------------------------------------------------
diff --git a/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_config.h b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_config.h
new file mode 100644
index 0000000..48adfcc
--- /dev/null
+++ b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_config.h
@@ -0,0 +1,74 @@
+/*
+ * Copyright 2017 The Abseil Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+
+ * Defines ABSL_STACKTRACE_INL_HEADER to the *-inl.h containing
+ * actual unwinder implementation.
+ * This header is "private" to stacktrace.cc.
+ * DO NOT include it into any other files.
+*/
+#ifndef ABSL_DEBUGGING_INTERNAL_STACKTRACE_CONFIG_H_
+#define ABSL_DEBUGGING_INTERNAL_STACKTRACE_CONFIG_H_
+
+// First, test platforms which only support a stub.
+#if ABSL_STACKTRACE_INL_HEADER
+#error ABSL_STACKTRACE_INL_HEADER cannot be directly set
+#elif defined(__native_client__) || defined(__APPLE__) || \
+    defined(__FreeBSD__) || defined(__ANDROID__) || defined(__myriad2__) || \
+    defined(__asmjs__) || defined(__wasm__) || defined(__Fuchsia__)
+#define ABSL_STACKTRACE_INL_HEADER \
+    "absl/debugging/internal/stacktrace_unimplemented-inl.inc"
+
+// Next, test for Mips and Windows.
+// TODO(marmstrong): Mips case, remove the check for ABSL_STACKTRACE_INL_HEADER
+#elif defined(__mips__) && !defined(ABSL_STACKTRACE_INL_HEADER)
+#define ABSL_STACKTRACE_INL_HEADER \
+    "absl/debugging/internal/stacktrace_unimplemented-inl.inc"
+#elif defined(_WIN32)  // windows
+#define ABSL_STACKTRACE_INL_HEADER \
+    "absl/debugging/internal/stacktrace_win32-inl.inc"
+
+// Finally, test NO_FRAME_POINTER.
+#elif !defined(NO_FRAME_POINTER)
+# if defined(__i386__) || defined(__x86_64__)
+#define ABSL_STACKTRACE_INL_HEADER \
+    "absl/debugging/internal/stacktrace_x86-inl.inc"
+# elif defined(__ppc__) || defined(__PPC__)
+#define ABSL_STACKTRACE_INL_HEADER \
+    "absl/debugging/internal/stacktrace_powerpc-inl.inc"
+# elif defined(__aarch64__)
+#define ABSL_STACKTRACE_INL_HEADER \
+    "absl/debugging/internal/stacktrace_aarch64-inl.inc"
+# elif defined(__arm__)
+#define ABSL_STACKTRACE_INL_HEADER \
+    "absl/debugging/internal/stacktrace_arm-inl.inc"
+# endif
+#else  // defined(NO_FRAME_POINTER)
+# if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__)
+#define ABSL_STACKTRACE_INL_HEADER \
+    "absl/debugging/internal/stacktrace_unimplemented-inl.inc"
+# elif defined(__ppc__) || defined(__PPC__)
+//  Use glibc's backtrace.
+#define ABSL_STACKTRACE_INL_HEADER \
+    "absl/debugging/internal/stacktrace_generic-inl.inc"
+# elif defined(__arm__)
+#   error stacktrace without frame pointer is not supported on ARM
+# endif
+#endif  // NO_FRAME_POINTER
+
+#if !defined(ABSL_STACKTRACE_INL_HEADER)
+#error Not supported yet
+#endif
+
+#endif  // ABSL_DEBUGGING_INTERNAL_STACKTRACE_CONFIG_H_

http://git-wip-us.apache.org/repos/asf/marmotta/blob/0eb556da/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_generic-inl.inc
----------------------------------------------------------------------
diff --git a/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_generic-inl.inc b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_generic-inl.inc
new file mode 100644
index 0000000..2c9ca41
--- /dev/null
+++ b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_generic-inl.inc
@@ -0,0 +1,59 @@
+// Copyright 2000 - 2007 Google Inc.
+// All rights reserved.
+//
+// Author: Sanjay Ghemawat
+//
+// Portable implementation - just use glibc
+//
+// Note:  The glibc implementation may cause a call to malloc.
+// This can cause a deadlock in HeapProfiler.
+
+#ifndef ABSL_DEBUGGING_INTERNAL_STACKTRACE_GENERIC_INL_H_
+#define ABSL_DEBUGGING_INTERNAL_STACKTRACE_GENERIC_INL_H_
+
+#include <execinfo.h>
+#include <cstring>
+
+#include "absl/debugging/stacktrace.h"
+
+template <bool IS_STACK_FRAMES, bool IS_WITH_CONTEXT>
+static int UnwindImpl(void** result, int* sizes, int max_depth, int skip_count,
+                      const void *ucp, int *min_dropped_frames) {
+  static const int kStackLength = 64;
+  void * stack[kStackLength];
+  int size;
+
+  size = backtrace(stack, kStackLength);
+  skip_count++;  // we want to skip the current frame as well
+  int result_count = size - skip_count;
+  if (result_count < 0)
+    result_count = 0;
+  if (result_count > max_depth)
+    result_count = max_depth;
+  for (int i = 0; i < result_count; i++)
+    result[i] = stack[i + skip_count];
+
+  if (IS_STACK_FRAMES) {
+    // No implementation for finding out the stack frame sizes yet.
+    memset(sizes, 0, sizeof(*sizes) * result_count);
+  }
+  if (min_dropped_frames != nullptr) {
+    if (size - skip_count - max_depth > 0) {
+      *min_dropped_frames = size - skip_count - max_depth;
+    } else {
+      *min_dropped_frames = 0;
+    }
+  }
+
+  return result_count;
+}
+
+namespace absl {
+namespace debugging_internal {
+bool StackTraceWorksForTest() {
+  return true;
+}
+}  // namespace debugging_internal
+}  // namespace absl
+
+#endif  // ABSL_DEBUGGING_INTERNAL_STACKTRACE_GENERIC_INL_H_

http://git-wip-us.apache.org/repos/asf/marmotta/blob/0eb556da/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_powerpc-inl.inc
----------------------------------------------------------------------
diff --git a/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_powerpc-inl.inc b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_powerpc-inl.inc
new file mode 100644
index 0000000..297bdad
--- /dev/null
+++ b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_powerpc-inl.inc
@@ -0,0 +1,243 @@
+// Copyright 2017 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// Produce stack trace.  I'm guessing (hoping!) the code is much like
+// for x86.  For apple machines, at least, it seems to be; see
+//    http://developer.apple.com/documentation/mac/runtimehtml/RTArch-59.html
+//    http://www.linux-foundation.org/spec/ELF/ppc64/PPC-elf64abi-1.9.html#STACK
+// Linux has similar code: http://patchwork.ozlabs.org/linuxppc/patch?id=8882
+
+#ifndef ABSL_DEBUGGING_INTERNAL_STACKTRACE_POWERPC_INL_H_
+#define ABSL_DEBUGGING_INTERNAL_STACKTRACE_POWERPC_INL_H_
+
+#if defined(__linux__)
+#include <asm/ptrace.h>   // for PT_NIP.
+#include <ucontext.h>     // for ucontext_t
+#endif
+
+#include <unistd.h>
+#include <cassert>
+#include <cstdint>
+#include <cstdio>
+
+#include "absl/base/port.h"
+#include "absl/debugging/stacktrace.h"
+#include "absl/debugging/internal/address_is_readable.h"
+#include "absl/debugging/internal/vdso_support.h"  // a no-op on non-elf or non-glibc systems
+
+// Given a stack pointer, return the saved link register value.
+// Note that this is the link register for a callee.
+static inline void *StacktracePowerPCGetLR(void **sp) {
+  // PowerPC has 3 main ABIs, which say where in the stack the
+  // Link Register is.  For DARWIN and AIX (used by apple and
+  // linux ppc64), it's in sp[2].  For SYSV (used by linux ppc),
+  // it's in sp[1].
+#if defined(_CALL_AIX) || defined(_CALL_DARWIN)
+  return *(sp+2);
+#elif defined(_CALL_SYSV)
+  return *(sp+1);
+#elif defined(__APPLE__) || defined(__FreeBSD__) || \
+    (defined(__linux__) && defined(__PPC64__))
+  // This check is in case the compiler doesn't define _CALL_AIX/etc.
+  return *(sp+2);
+#elif defined(__linux)
+  // This check is in case the compiler doesn't define _CALL_SYSV.
+  return *(sp+1);
+#else
+#error Need to specify the PPC ABI for your archiecture.
+#endif
+}
+
+// Given a pointer to a stack frame, locate and return the calling
+// stackframe, or return null if no stackframe can be found. Perform sanity
+// checks (the strictness of which is controlled by the boolean parameter
+// "STRICT_UNWINDING") to reduce the chance that a bad pointer is returned.
+template<bool STRICT_UNWINDING, bool IS_WITH_CONTEXT>
+ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS  // May read random elements from stack.
+ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY   // May read random elements from stack.
+static void **NextStackFrame(void **old_sp, const void *uc) {
+  void **new_sp = (void **) *old_sp;
+  enum { kStackAlignment = 16 };
+
+  // Check that the transition from frame pointer old_sp to frame
+  // pointer new_sp isn't clearly bogus
+  if (STRICT_UNWINDING) {
+    // With the stack growing downwards, older stack frame must be
+    // at a greater address that the current one.
+    if (new_sp <= old_sp) return nullptr;
+    // Assume stack frames larger than 100,000 bytes are bogus.
+    if ((uintptr_t)new_sp - (uintptr_t)old_sp > 100000) return nullptr;
+  } else {
+    // In the non-strict mode, allow discontiguous stack frames.
+    // (alternate-signal-stacks for example).
+    if (new_sp == old_sp) return nullptr;
+    // And allow frames upto about 1MB.
+    if ((new_sp > old_sp)
+        && ((uintptr_t)new_sp - (uintptr_t)old_sp > 1000000)) return nullptr;
+  }
+  if ((uintptr_t)new_sp % kStackAlignment != 0) return nullptr;
+
+#if defined(__linux__)
+  enum StackTraceKernelSymbolStatus {
+      kNotInitialized = 0, kAddressValid, kAddressInvalid };
+
+  if (IS_WITH_CONTEXT && uc != nullptr) {
+    static StackTraceKernelSymbolStatus kernel_symbol_status =
+        kNotInitialized;  // Sentinel: not computed yet.
+    // Initialize with sentinel value: __kernel_rt_sigtramp_rt64 can not
+    // possibly be there.
+    static const unsigned char *kernel_sigtramp_rt64_address = nullptr;
+    if (kernel_symbol_status == kNotInitialized) {
+      absl::debugging_internal::VDSOSupport vdso;
+      if (vdso.IsPresent()) {
+        absl::debugging_internal::VDSOSupport::SymbolInfo
+            sigtramp_rt64_symbol_info;
+        if (!vdso.LookupSymbol(
+                "__kernel_sigtramp_rt64", "LINUX_2.6.15",
+                absl::debugging_internal::VDSOSupport::kVDSOSymbolType,
+                &sigtramp_rt64_symbol_info) ||
+            sigtramp_rt64_symbol_info.address == nullptr) {
+          // Unexpected: VDSO is present, yet the expected symbol is missing
+          // or null.
+          assert(false && "VDSO is present, but doesn't have expected symbol");
+          kernel_symbol_status = kAddressInvalid;
+        } else {
+          kernel_sigtramp_rt64_address =
+              reinterpret_cast<const unsigned char *>(
+                  sigtramp_rt64_symbol_info.address);
+          kernel_symbol_status = kAddressValid;
+        }
+      } else {
+        kernel_symbol_status = kAddressInvalid;
+      }
+    }
+
+    if (new_sp != nullptr &&
+        kernel_symbol_status == kAddressValid &&
+        StacktracePowerPCGetLR(new_sp) == kernel_sigtramp_rt64_address) {
+      const ucontext_t* signal_context =
+          reinterpret_cast<const ucontext_t*>(uc);
+      void **const sp_before_signal =
+          reinterpret_cast<void**>(signal_context->uc_mcontext.gp_regs[PT_R1]);
+      // Check that alleged sp before signal is nonnull and is reasonably
+      // aligned.
+      if (sp_before_signal != nullptr &&
+          ((uintptr_t)sp_before_signal % kStackAlignment) == 0) {
+        // Check that alleged stack pointer is actually readable. This is to
+        // prevent a "double fault" in case we hit the first fault due to e.g.
+        // a stack corruption.
+        if (absl::debugging_internal::AddressIsReadable(sp_before_signal)) {
+          // Alleged stack pointer is readable, use it for further unwinding.
+          new_sp = sp_before_signal;
+        }
+      }
+    }
+  }
+#endif
+
+  return new_sp;
+}
+
+// This ensures that absl::GetStackTrace sets up the Link Register properly.
+void StacktracePowerPCDummyFunction() __attribute__((noinline));
+void StacktracePowerPCDummyFunction() { __asm__ volatile(""); }
+
+template <bool IS_STACK_FRAMES, bool IS_WITH_CONTEXT>
+ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS  // May read random elements from stack.
+ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY   // May read random elements from stack.
+static int UnwindImpl(void** result, int* sizes, int max_depth, int skip_count,
+                      const void *ucp, int *min_dropped_frames) {
+  void **sp;
+  // Apple OS X uses an old version of gnu as -- both Darwin 7.9.0 (Panther)
+  // and Darwin 8.8.1 (Tiger) use as 1.38.  This means we have to use a
+  // different asm syntax.  I don't know quite the best way to discriminate
+  // systems using the old as from the new one; I've gone with __APPLE__.
+#ifdef __APPLE__
+  __asm__ volatile ("mr %0,r1" : "=r" (sp));
+#else
+  __asm__ volatile ("mr %0,1" : "=r" (sp));
+#endif
+
+  // On PowerPC, the "Link Register" or "Link Record" (LR), is a stack
+  // entry that holds the return address of the subroutine call (what
+  // instruction we run after our function finishes).  This is the
+  // same as the stack-pointer of our parent routine, which is what we
+  // want here.  While the compiler will always(?) set up LR for
+  // subroutine calls, it may not for leaf functions (such as this one).
+  // This routine forces the compiler (at least gcc) to push it anyway.
+  StacktracePowerPCDummyFunction();
+
+  // The LR save area is used by the callee, so the top entry is bogus.
+  skip_count++;
+
+  int n = 0;
+
+  // Unlike ABIs of X86 and ARM, PowerPC ABIs say that return address (in
+  // the link register) of a function call is stored in the caller's stack
+  // frame instead of the callee's.  When we look for the return address
+  // associated with a stack frame, we need to make sure that there is a
+  // caller frame before it.  So we call NextStackFrame before entering the
+  // loop below and check next_sp instead of sp for loop termination.
+  // The outermost frame is set up by runtimes and it does not have a
+  // caller frame, so it is skipped.
+
+  // The absl::GetStackFrames routine is called when we are in some
+  // informational context (the failure signal handler for example).
+  // Use the non-strict unwinding rules to produce a stack trace
+  // that is as complete as possible (even if it contains a few
+  // bogus entries in some rare cases).
+  void **next_sp = NextStackFrame<!IS_STACK_FRAMES, IS_WITH_CONTEXT>(sp, ucp);
+
+  while (next_sp && n < max_depth) {
+    if (skip_count > 0) {
+      skip_count--;
+    } else {
+      result[n] = StacktracePowerPCGetLR(sp);
+      if (IS_STACK_FRAMES) {
+        if (next_sp > sp) {
+          sizes[n] = (uintptr_t)next_sp - (uintptr_t)sp;
+        } else {
+          // A frame-size of 0 is used to indicate unknown frame size.
+          sizes[n] = 0;
+        }
+      }
+      n++;
+    }
+
+    sp = next_sp;
+    next_sp = NextStackFrame<!IS_STACK_FRAMES, IS_WITH_CONTEXT>(sp, ucp);
+  }
+
+  if (min_dropped_frames != nullptr) {
+    // Implementation detail: we clamp the max of frames we are willing to
+    // count, so as not to spend too much time in the loop below.
+    const int kMaxUnwind = 1000;
+    int j = 0;
+    for (; next_sp != nullptr && j < kMaxUnwind; j++) {
+      next_sp = NextStackFrame<!IS_STACK_FRAMES, IS_WITH_CONTEXT>(next_sp, ucp);
+    }
+    *min_dropped_frames = j;
+  }
+  return n;
+}
+
+namespace absl {
+namespace debugging_internal {
+bool StackTraceWorksForTest() {
+  return true;
+}
+}  // namespace debugging_internal
+}  // namespace absl
+
+#endif  // ABSL_DEBUGGING_INTERNAL_STACKTRACE_POWERPC_INL_H_

http://git-wip-us.apache.org/repos/asf/marmotta/blob/0eb556da/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_unimplemented-inl.inc
----------------------------------------------------------------------
diff --git a/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_unimplemented-inl.inc b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_unimplemented-inl.inc
new file mode 100644
index 0000000..e256fdd
--- /dev/null
+++ b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_unimplemented-inl.inc
@@ -0,0 +1,22 @@
+#ifndef ABSL_DEBUGGING_INTERNAL_STACKTRACE_UNIMPLEMENTED_INL_H_
+#define ABSL_DEBUGGING_INTERNAL_STACKTRACE_UNIMPLEMENTED_INL_H_
+
+template <bool IS_STACK_FRAMES, bool IS_WITH_CONTEXT>
+static int UnwindImpl(void** /* result */, int* /* sizes */,
+                      int /* max_depth */, int /* skip_count */,
+                      const void* /* ucp */, int *min_dropped_frames) {
+  if (min_dropped_frames != nullptr) {
+    *min_dropped_frames = 0;
+  }
+  return 0;
+}
+
+namespace absl {
+namespace debugging_internal {
+bool StackTraceWorksForTest() {
+  return false;
+}
+}  // namespace debugging_internal
+}  // namespace absl
+
+#endif  // ABSL_DEBUGGING_INTERNAL_STACKTRACE_UNIMPLEMENTED_INL_H_

http://git-wip-us.apache.org/repos/asf/marmotta/blob/0eb556da/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_win32-inl.inc
----------------------------------------------------------------------
diff --git a/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_win32-inl.inc b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_win32-inl.inc
new file mode 100644
index 0000000..a8f8a56
--- /dev/null
+++ b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_win32-inl.inc
@@ -0,0 +1,83 @@
+// Copyright 2017 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// Produces a stack trace for Windows.  Normally, one could use
+// stacktrace_x86-inl.h or stacktrace_x86_64-inl.h -- and indeed, that
+// should work for binaries compiled using MSVC in "debug" mode.
+// However, in "release" mode, Windows uses frame-pointer
+// optimization, which makes getting a stack trace very difficult.
+//
+// There are several approaches one can take.  One is to use Windows
+// intrinsics like StackWalk64.  These can work, but have restrictions
+// on how successful they can be.  Another attempt is to write a
+// version of stacktrace_x86-inl.h that has heuristic support for
+// dealing with FPO, similar to what WinDbg does (see
+// http://www.nynaeve.net/?p=97).  There are (non-working) examples of
+// these approaches, complete with TODOs, in stacktrace_win32-inl.h#1
+//
+// The solution we've ended up doing is to call the undocumented
+// windows function RtlCaptureStackBackTrace, which probably doesn't
+// work with FPO but at least is fast, and doesn't require a symbol
+// server.
+//
+// This code is inspired by a patch from David Vitek:
+//   http://code.google.com/p/google-perftools/issues/detail?id=83
+
+#ifndef ABSL_DEBUGGING_INTERNAL_STACKTRACE_WIN32_INL_H_
+#define ABSL_DEBUGGING_INTERNAL_STACKTRACE_WIN32_INL_H_
+
+#include <windows.h>    // for GetProcAddress and GetModuleHandle
+#include <cassert>
+
+typedef USHORT NTAPI RtlCaptureStackBackTrace_Function(
+    IN ULONG frames_to_skip,
+    IN ULONG frames_to_capture,
+    OUT PVOID *backtrace,
+    OUT PULONG backtrace_hash);
+
+// Load the function we need at static init time, where we don't have
+// to worry about someone else holding the loader's lock.
+static RtlCaptureStackBackTrace_Function* const RtlCaptureStackBackTrace_fn =
+   (RtlCaptureStackBackTrace_Function*)
+   GetProcAddress(GetModuleHandleA("ntdll.dll"), "RtlCaptureStackBackTrace");
+
+template <bool IS_STACK_FRAMES, bool IS_WITH_CONTEXT>
+static int UnwindImpl(void** result, int* sizes, int max_depth, int skip_count,
+                      const void *ucp, int *min_dropped_frames) {
+  int n = 0;
+  if (!RtlCaptureStackBackTrace_fn) {
+    // can't find a stacktrace with no function to call
+  } else {
+    n = (int)RtlCaptureStackBackTrace_fn(skip_count + 2, max_depth, result, 0);
+  }
+  if (IS_STACK_FRAMES) {
+    // No implementation for finding out the stack frame sizes yet.
+    memset(sizes, 0, sizeof(*sizes) * n);
+  }
+  if (min_dropped_frames != nullptr) {
+    // Not implemented.
+    *min_dropped_frames = 0;
+  }
+  return n;
+}
+
+namespace absl {
+namespace debugging_internal {
+bool StackTraceWorksForTest() {
+  return false;
+}
+}  // namespace debugging_internal
+}  // namespace absl
+
+#endif  // ABSL_DEBUGGING_INTERNAL_STACKTRACE_WIN32_INL_H_

http://git-wip-us.apache.org/repos/asf/marmotta/blob/0eb556da/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_x86-inl.inc
----------------------------------------------------------------------
diff --git a/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_x86-inl.inc b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_x86-inl.inc
new file mode 100644
index 0000000..ac85b92
--- /dev/null
+++ b/libraries/ostrich/backend/3rdparty/abseil/absl/debugging/internal/stacktrace_x86-inl.inc
@@ -0,0 +1,337 @@
+// Copyright 2017 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// Produce stack trace
+
+#ifndef ABSL_DEBUGGING_INTERNAL_STACKTRACE_X86_INL_INC_
+#define ABSL_DEBUGGING_INTERNAL_STACKTRACE_X86_INL_INC_
+
+#if defined(__linux__) && (defined(__i386__) || defined(__x86_64__))
+#include <ucontext.h>  // for ucontext_t
+#endif
+
+#if !defined(_WIN32)
+#include <unistd.h>
+#endif
+
+#include <cassert>
+#include <cstdint>
+
+#include "absl/base/macros.h"
+#include "absl/base/port.h"
+#include "absl/debugging/internal/address_is_readable.h"
+#include "absl/debugging/internal/vdso_support.h"  // a no-op on non-elf or non-glibc systems
+#include "absl/debugging/stacktrace.h"
+#include "absl/base/internal/raw_logging.h"
+
+#if defined(__linux__) && defined(__i386__)
+// Count "push %reg" instructions in VDSO __kernel_vsyscall(),
+// preceeding "syscall" or "sysenter".
+// If __kernel_vsyscall uses frame pointer, answer 0.
+//
+// kMaxBytes tells how many instruction bytes of __kernel_vsyscall
+// to analyze before giving up. Up to kMaxBytes+1 bytes of
+// instructions could be accessed.
+//
+// Here are known __kernel_vsyscall instruction sequences:
+//
+// SYSENTER (linux-2.6.26/arch/x86/vdso/vdso32/sysenter.S).
+// Used on Intel.
+//  0xffffe400 <__kernel_vsyscall+0>:       push   %ecx
+//  0xffffe401 <__kernel_vsyscall+1>:       push   %edx
+//  0xffffe402 <__kernel_vsyscall+2>:       push   %ebp
+//  0xffffe403 <__kernel_vsyscall+3>:       mov    %esp,%ebp
+//  0xffffe405 <__kernel_vsyscall+5>:       sysenter
+//
+// SYSCALL (see linux-2.6.26/arch/x86/vdso/vdso32/syscall.S).
+// Used on AMD.
+//  0xffffe400 <__kernel_vsyscall+0>:       push   %ebp
+//  0xffffe401 <__kernel_vsyscall+1>:       mov    %ecx,%ebp
+//  0xffffe403 <__kernel_vsyscall+3>:       syscall
+//
+
+// The sequence below isn't actually expected in Google fleet,
+// here only for completeness. Remove this comment from OSS release.
+
+// i386 (see linux-2.6.26/arch/x86/vdso/vdso32/int80.S)
+//  0xffffe400 <__kernel_vsyscall+0>:       int $0x80
+//  0xffffe401 <__kernel_vsyscall+1>:       ret
+//
+static const int kMaxBytes = 10;
+
+// We use assert()s instead of DCHECK()s -- this is too low level
+// for DCHECK().
+
+static int CountPushInstructions(const unsigned char *const addr) {
+  int result = 0;
+  for (int i = 0; i < kMaxBytes; ++i) {
+    if (addr[i] == 0x89) {
+      // "mov reg,reg"
+      if (addr[i + 1] == 0xE5) {
+        // Found "mov %esp,%ebp".
+        return 0;  
+      }
+      ++i;  // Skip register encoding byte.
+    } else if (addr[i] == 0x0F &&
+               (addr[i + 1] == 0x34 || addr[i + 1] == 0x05)) {
+      // Found "sysenter" or "syscall".
+      return result;
+    } else if ((addr[i] & 0xF0) == 0x50) {
+      // Found "push %reg".
+      ++result;
+    } else if (addr[i] == 0xCD && addr[i + 1] == 0x80) {
+      // Found "int $0x80"
+      assert(result == 0);
+      return 0;
+    } else {
+      // Unexpected instruction.
+      assert(false && "unexpected instruction in __kernel_vsyscall");
+      return 0;
+    }
+  }
+  // Unexpected: didn't find SYSENTER or SYSCALL in
+  // [__kernel_vsyscall, __kernel_vsyscall + kMaxBytes) interval.
+  assert(false && "did not find SYSENTER or SYSCALL in __kernel_vsyscall");
+  return 0;
+}
+#endif
+
+// Assume stack frames larger than 100,000 bytes are bogus.
+static const int kMaxFrameBytes = 100000;
+
+// Returns the stack frame pointer from signal context, 0 if unknown.
+// vuc is a ucontext_t *.  We use void* to avoid the use
+// of ucontext_t on non-POSIX systems.
+static uintptr_t GetFP(const void *vuc) {
+#if !defined(__linux__)
+  static_cast<void>(vuc);  // Avoid an unused argument compiler warning.
+#else
+  if (vuc != nullptr) {
+    auto *uc = reinterpret_cast<const ucontext_t *>(vuc);
+#if defined(__i386__)
+    const auto bp = uc->uc_mcontext.gregs[REG_EBP];
+    const auto sp = uc->uc_mcontext.gregs[REG_ESP];
+#elif defined(__x86_64__)
+    const auto bp = uc->uc_mcontext.gregs[REG_RBP];
+    const auto sp = uc->uc_mcontext.gregs[REG_RSP];
+#else
+    const uintptr_t bp = 0;
+    const uintptr_t sp = 0;
+#endif
+    // Sanity-check that the base pointer is valid.  It should be as long as
+    // SHRINK_WRAP_FRAME_POINTER is not set, but it's possible that some code in
+    // the process is compiled with --copt=-fomit-frame-pointer or
+    // --copt=-momit-leaf-frame-pointer.
+    //
+    // TODO(bcmills): -momit-leaf-frame-pointer is currently the default
+    // behavior when building with clang.  Talk to the C++ toolchain team about
+    // fixing that.
+    if (bp >= sp && bp - sp <= kMaxFrameBytes) return bp;
+
+    // If bp isn't a plausible frame pointer, return the stack pointer instead.
+    // If we're lucky, it points to the start of a stack frame; otherwise, we'll
+    // get one frame of garbage in the stack trace and fail the sanity check on
+    // the next iteration.
+    return sp;
+  }
+#endif
+  return 0;
+}
+
+// Given a pointer to a stack frame, locate and return the calling
+// stackframe, or return null if no stackframe can be found. Perform sanity
+// checks (the strictness of which is controlled by the boolean parameter
+// "STRICT_UNWINDING") to reduce the chance that a bad pointer is returned.
+template <bool STRICT_UNWINDING, bool WITH_CONTEXT>
+ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS  // May read random elements from stack.
+ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY   // May read random elements from stack.
+static void **NextStackFrame(void **old_fp, const void *uc) {
+  void **new_fp = (void **)*old_fp;
+
+#if defined(__linux__) && defined(__i386__)
+  if (WITH_CONTEXT && uc != nullptr) {
+    // How many "push %reg" instructions are there at __kernel_vsyscall?
+    // This is constant for a given kernel and processor, so compute
+    // it only once.
+    static int num_push_instructions = -1;  // Sentinel: not computed yet.
+    // Initialize with sentinel value: __kernel_rt_sigreturn can not possibly
+    // be there.
+    static const unsigned char *kernel_rt_sigreturn_address = nullptr;
+    static const unsigned char *kernel_vsyscall_address = nullptr;
+    if (num_push_instructions == -1) {
+      absl::debugging_internal::VDSOSupport vdso;
+      if (vdso.IsPresent()) {
+        absl::debugging_internal::VDSOSupport::SymbolInfo
+            rt_sigreturn_symbol_info;
+        absl::debugging_internal::VDSOSupport::SymbolInfo vsyscall_symbol_info;
+        if (!vdso.LookupSymbol("__kernel_rt_sigreturn", "LINUX_2.5", STT_FUNC,
+                               &rt_sigreturn_symbol_info) ||
+            !vdso.LookupSymbol("__kernel_vsyscall", "LINUX_2.5", STT_FUNC,
+                               &vsyscall_symbol_info) ||
+            rt_sigreturn_symbol_info.address == nullptr ||
+            vsyscall_symbol_info.address == nullptr) {
+          // Unexpected: 32-bit VDSO is present, yet one of the expected
+          // symbols is missing or null.
+          assert(false && "VDSO is present, but doesn't have expected symbols");
+          num_push_instructions = 0;
+        } else {
+          kernel_rt_sigreturn_address =
+              reinterpret_cast<const unsigned char *>(
+                  rt_sigreturn_symbol_info.address);
+          kernel_vsyscall_address =
+              reinterpret_cast<const unsigned char *>(
+                  vsyscall_symbol_info.address);
+          num_push_instructions =
+              CountPushInstructions(kernel_vsyscall_address);
+        }
+      } else {
+        num_push_instructions = 0;
+      }
+    }
+    if (num_push_instructions != 0 && kernel_rt_sigreturn_address != nullptr &&
+        old_fp[1] == kernel_rt_sigreturn_address) {
+      const ucontext_t *ucv = static_cast<const ucontext_t *>(uc);
+      // This kernel does not use frame pointer in its VDSO code,
+      // and so %ebp is not suitable for unwinding.
+      void **const reg_ebp =
+          reinterpret_cast<void **>(ucv->uc_mcontext.gregs[REG_EBP]);
+      const unsigned char *const reg_eip =
+          reinterpret_cast<unsigned char *>(ucv->uc_mcontext.gregs[REG_EIP]);
+      if (new_fp == reg_ebp && kernel_vsyscall_address <= reg_eip &&
+          reg_eip - kernel_vsyscall_address < kMaxBytes) {
+        // We "stepped up" to __kernel_vsyscall, but %ebp is not usable.
+        // Restore from 'ucv' instead.
+        void **const reg_esp =
+            reinterpret_cast<void **>(ucv->uc_mcontext.gregs[REG_ESP]);
+        // Check that alleged %esp is not null and is reasonably aligned.
+        if (reg_esp &&
+            ((uintptr_t)reg_esp & (sizeof(reg_esp) - 1)) == 0) {
+          // Check that alleged %esp is actually readable. This is to prevent
+          // "double fault" in case we hit the first fault due to e.g. stack
+          // corruption.
+          void *const reg_esp2 = reg_esp[num_push_instructions - 1];
+          if (absl::debugging_internal::AddressIsReadable(reg_esp2)) {
+            // Alleged %esp is readable, use it for further unwinding.
+            new_fp = reinterpret_cast<void **>(reg_esp2);
+          }
+        }
+      }
+    }
+  }
+#endif
+
+  const uintptr_t old_fp_u = reinterpret_cast<uintptr_t>(old_fp);
+  const uintptr_t new_fp_u = reinterpret_cast<uintptr_t>(new_fp);
+
+  // Check that the transition from frame pointer old_fp to frame
+  // pointer new_fp isn't clearly bogus.  Skip the checks if new_fp
+  // matches the signal context, so that we don't skip out early when
+  // using an alternate signal stack.
+  //
+  // TODO(bcmills): The GetFP call should be completely unnecessary when
+  // SHRINK_WRAP_FRAME_POINTER is set (because we should be back in the thread's
+  // stack by this point), but it is empirically still needed (e.g. when the
+  // stack includes a call to abort).  unw_get_reg returns UNW_EBADREG for some
+  // frames.  Figure out why GetValidFrameAddr and/or libunwind isn't doing what
+  // it's supposed to.
+  if (STRICT_UNWINDING &&
+      (!WITH_CONTEXT || uc == nullptr || new_fp_u != GetFP(uc))) {
+    // With the stack growing downwards, older stack frame must be
+    // at a greater address that the current one.
+    if (new_fp_u <= old_fp_u) return nullptr;
+    if (new_fp_u - old_fp_u > kMaxFrameBytes) return nullptr;
+  } else {
+    if (new_fp == nullptr) return nullptr;  // skip AddressIsReadable() below
+    // In the non-strict mode, allow discontiguous stack frames.
+    // (alternate-signal-stacks for example).
+    if (new_fp == old_fp) return nullptr;
+  }
+
+  if (new_fp_u & (sizeof(void *) - 1)) return nullptr;
+#ifdef __i386__
+  // On 32-bit machines, the stack pointer can be very close to
+  // 0xffffffff, so we explicitly check for a pointer into the
+  // last two pages in the address space
+  if (new_fp_u >= 0xffffe000) return nullptr;
+#endif
+#if !defined(_WIN32)
+  if (!STRICT_UNWINDING) {
+    // Lax sanity checks cause a crash in 32-bit tcmalloc/crash_reason_test
+    // on AMD-based machines with VDSO-enabled kernels.
+    // Make an extra sanity check to insure new_fp is readable.
+    // Note: NextStackFrame<false>() is only called while the program
+    //       is already on its last leg, so it's ok to be slow here.
+
+    if (!absl::debugging_internal::AddressIsReadable(new_fp)) {
+      return nullptr;
+    }
+  }
+#endif
+  return new_fp;
+}
+
+template <bool IS_STACK_FRAMES, bool IS_WITH_CONTEXT>
+ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS  // May read random elements from stack.
+ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY   // May read random elements from stack.
+ABSL_ATTRIBUTE_NOINLINE
+static int UnwindImpl(void **result, int *sizes, int max_depth, int skip_count,
+                      const void *ucp, int *min_dropped_frames) {
+  int n = 0;
+  void **fp = reinterpret_cast<void **>(__builtin_frame_address(0));
+
+  while (fp && n < max_depth) {
+    if (*(fp + 1) == reinterpret_cast<void *>(0)) {
+      // In 64-bit code, we often see a frame that
+      // points to itself and has a return address of 0.
+      break;
+    }
+    void **next_fp = NextStackFrame<!IS_STACK_FRAMES, IS_WITH_CONTEXT>(fp, ucp);
+    if (skip_count > 0) {
+      skip_count--;
+    } else {
+      result[n] = *(fp + 1);
+      if (IS_STACK_FRAMES) {
+        if (next_fp > fp) {
+          sizes[n] = (uintptr_t)next_fp - (uintptr_t)fp;
+        } else {
+          // A frame-size of 0 is used to indicate unknown frame size.
+          sizes[n] = 0;
+        }
+      }
+      n++;
+    }
+    fp = next_fp;
+  }
+  if (min_dropped_frames != nullptr) {
+    // Implementation detail: we clamp the max of frames we are willing to
+    // count, so as not to spend too much time in the loop below.
+    const int kMaxUnwind = 1000;
+    int j = 0;
+    for (; fp != nullptr && j < kMaxUnwind; j++) {
+      fp = NextStackFrame<!IS_STACK_FRAMES, IS_WITH_CONTEXT>(fp, ucp);
+    }
+    *min_dropped_frames = j;
+  }
+  return n;
+}
+
+namespace absl {
+namespace debugging_internal {
+bool StackTraceWorksForTest() {
+  return true;
+}
+}  // namespace debugging_internal
+}  // namespace absl
+
+#endif  // ABSL_DEBUGGING_INTERNAL_STACKTRACE_X86_INL_INC_