chore(3p/abseil_cpp): unvendor abseil_cpp r/3786

we weren't actually using these sources anymore, okay?

Change-Id: If701571d9716de308d3512e1eb22c35db0877a66
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5248
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
Autosubmit: tazjin <tazjin@tvl.su>

1 files changed, 0 insertions, 248 deletions

diff --git a/third_party/abseil_cpp/absl/debugging/internal/stacktrace_powerpc-inl.inc b/third_party/abseil_cpp/absl/debugging/internal/stacktrace_powerpc-inl.inc
deleted file mode 100644
index 2e7c2f404f20..000000000000
--- a/third_party/abseil_cpp/absl/debugging/internal/stacktrace_powerpc-inl.inc
+++ /dev/null
@@ -1,248 +0,0 @@
-// 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
-//
-//      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.
-//
-// Produce stack trace.  I'm guessing (hoping!) the code is much like
-// for x86.  For apple machines, at least, it seems to be; see
-//    https://developer.apple.com/documentation/mac/runtimehtml/RTArch-59.html
-//    https://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/attributes.h"
-#include "absl/base/optimization.h"
-#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.
-ABSL_ATTRIBUTE_NOINLINE static void AbslStacktracePowerPCDummyFunction() {
-  ABSL_BLOCK_TAIL_CALL_OPTIMIZATION();
-}
-
-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 macOS 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.
-  AbslStacktracePowerPCDummyFunction();
-
-  // 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 {
-ABSL_NAMESPACE_BEGIN
-namespace debugging_internal {
-bool StackTraceWorksForTest() {
-  return true;
-}
-}  // namespace debugging_internal
-ABSL_NAMESPACE_END
-}  // namespace absl
-
-#endif  // ABSL_DEBUGGING_INTERNAL_STACKTRACE_POWERPC_INL_H_