Add 'third_party/abseil_cpp/' from commit '768eb2ca28'

git-subtree-dir: third_party/abseil_cpp
git-subtree-mainline: ffb2ae54be
git-subtree-split: 768eb2ca28

third_party/abseil_cpp/absl/debugging/internal/symbolize.h

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+// 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
+//
+//      https://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.
+
+// This file contains internal parts of the Abseil symbolizer.
+// Do not depend on the anything in this file, it may change at anytime.
+
+#ifndef ABSL_DEBUGGING_INTERNAL_SYMBOLIZE_H_
+#define ABSL_DEBUGGING_INTERNAL_SYMBOLIZE_H_
+
+#include <cstddef>
+#include <cstdint>
+
+#include "absl/base/config.h"
+
+#ifdef ABSL_INTERNAL_HAVE_ELF_SYMBOLIZE
+#error ABSL_INTERNAL_HAVE_ELF_SYMBOLIZE cannot be directly set
+#elif defined(__ELF__) && defined(__GLIBC__) && !defined(__native_client__) && \
+    !defined(__asmjs__) && !defined(__wasm__)
+#define ABSL_INTERNAL_HAVE_ELF_SYMBOLIZE 1
+
+#include <elf.h>
+#include <link.h>  // For ElfW() macro.
+#include <functional>
+#include <string>
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace debugging_internal {
+
+// Iterates over all sections, invoking callback on each with the section name
+// and the section header.
+//
+// Returns true on success; otherwise returns false in case of errors.
+//
+// This is not async-signal-safe.
+bool ForEachSection(int fd,
+                    const std::function<bool(const std::string& name,
+                                             const ElfW(Shdr) &)>& callback);
+
+// Gets the section header for the given name, if it exists. Returns true on
+// success. Otherwise, returns false.
+bool GetSectionHeaderByName(int fd, const char *name, size_t name_len,
+                            ElfW(Shdr) *out);
+
+}  // namespace debugging_internal
+ABSL_NAMESPACE_END
+}  // namespace absl
+
+#endif  // ABSL_INTERNAL_HAVE_ELF_SYMBOLIZE
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace debugging_internal {
+
+struct SymbolDecoratorArgs {
+  // The program counter we are getting symbolic name for.
+  const void *pc;
+  // 0 for main executable, load address for shared libraries.
+  ptrdiff_t relocation;
+  // Read-only file descriptor for ELF image covering "pc",
+  // or -1 if no such ELF image exists in /proc/self/maps.
+  int fd;
+  // Output buffer, size.
+  // Note: the buffer may not be empty -- default symbolizer may have already
+  // produced some output, and earlier decorators may have adorned it in
+  // some way. You are free to replace or augment the contents (within the
+  // symbol_buf_size limit).
+  char *const symbol_buf;
+  size_t symbol_buf_size;
+  // Temporary scratch space, size.
+  // Use that space in preference to allocating your own stack buffer to
+  // conserve stack.
+  char *const tmp_buf;
+  size_t tmp_buf_size;
+  // User-provided argument
+  void* arg;
+};
+using SymbolDecorator = void (*)(const SymbolDecoratorArgs *);
+
+// Installs a function-pointer as a decorator. Returns a value less than zero
+// if the system cannot install the decorator. Otherwise, returns a unique
+// identifier corresponding to the decorator. This identifier can be used to
+// uninstall the decorator - See RemoveSymbolDecorator() below.
+int InstallSymbolDecorator(SymbolDecorator decorator, void* arg);
+
+// Removes a previously installed function-pointer decorator. Parameter "ticket"
+// is the return-value from calling InstallSymbolDecorator().
+bool RemoveSymbolDecorator(int ticket);
+
+// Remove all installed decorators.  Returns true if successful, false if
+// symbolization is currently in progress.
+bool RemoveAllSymbolDecorators(void);
+
+// Registers an address range to a file mapping.
+//
+// Preconditions:
+//   start <= end
+//   filename != nullptr
+//
+// Returns true if the file was successfully registered.
+bool RegisterFileMappingHint(
+    const void* start, const void* end, uint64_t offset, const char* filename);
+
+// Looks up the file mapping registered by RegisterFileMappingHint for an
+// address range. If there is one, the file name is stored in *filename and
+// *start and *end are modified to reflect the registered mapping. Returns
+// whether any hint was found.
+bool GetFileMappingHint(const void** start,
+                        const void** end,
+                        uint64_t    *  offset,
+                        const char** filename);
+
+}  // namespace debugging_internal
+ABSL_NAMESPACE_END
+}  // namespace absl
+
+#endif  // ABSL_DEBUGGING_INTERNAL_SYMBOLIZE_H_