Add libc++ and libc++abi to third-party.

third_party/libc++abi/src/Unwind/UnwindLevel1-gcc-ext.c

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