[lldb] Remove support and workarounds for Android 4 and older (#124047)

lldb/cmake/modules/LLDBConfig.cmake

@@ -306,9 +306,4 @@ else()
     set(LLDB_CAN_USE_DEBUGSERVER OFF)
 endif()
 
-if ((CMAKE_SYSTEM_NAME MATCHES "Android") AND LLVM_BUILD_STATIC AND
-    ((ANDROID_ABI MATCHES "armeabi") OR (ANDROID_ABI MATCHES "mips")))
-  add_definitions(-DANDROID_USE_ACCEPT_WORKAROUND)
-endif()
-
 include(LLDBGenerateConfig)

lldb/include/lldb/Host/Time.h

@@ -11,15 +11,6 @@
 #ifndef LLDB_HOST_TIME_H
 #define LLDB_HOST_TIME_H
 
-#ifdef __ANDROID__
-#include <android/api-level.h>
-#endif
-
-#if defined(__ANDROID_API__) && __ANDROID_API__ < 21
-#include <time64.h>
-extern time_t timegm(struct tm *t);
-#else
 #include <ctime>
-#endif
 
 #endif // LLDB_HOST_TIME_H

lldb/source/Host/CMakeLists.txt

@@ -113,7 +113,6 @@ else()
     if (CMAKE_SYSTEM_NAME MATCHES "Android")
       add_host_subdirectory(android
         android/HostInfoAndroid.cpp
-        android/LibcGlue.cpp
         )
     endif()
   elseif (CMAKE_SYSTEM_NAME MATCHES "FreeBSD")

lldb/source/Host/android/LibcGlue.cpp

@@ -1,28 +0,0 @@
-//===-- LibcGlue.cpp ------------------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-// This files adds functions missing from libc on earlier versions of Android
-
-#include <android/api-level.h>
-
-#include <sys/syscall.h>
-
-#if __ANDROID_API__ < 21
-
-#include <csignal>
-#include <fcntl.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-
-#include "lldb/Host/Time.h"
-
-time_t timegm(struct tm *t) { return (time_t)timegm64(t); }
-
-int posix_openpt(int flags) { return open("/dev/ptmx", flags); }
-
-#endif

lldb/source/Host/common/Socket.cpp

@@ -472,23 +472,7 @@ Status Socket::Accept(const Timeout<std::micro> &timeout, Socket *&socket) {
 NativeSocket Socket::AcceptSocket(NativeSocket sockfd, struct sockaddr *addr,
                                   socklen_t *addrlen, Status &error) {
   error.Clear();
-#if defined(ANDROID_USE_ACCEPT_WORKAROUND)
-  // Hack:
-  // This enables static linking lldb-server to an API 21 libc, but still
-  // having it run on older devices. It is necessary because API 21 libc's
-  // implementation of accept() uses the accept4 syscall(), which is not
-  // available in older kernels. Using an older libc would fix this issue, but
-  // introduce other ones, as the old libraries were quite buggy.
-  int fd = syscall(__NR_accept, sockfd, addr, addrlen);
-  if (fd >= 0) {
-    int flags = ::fcntl(fd, F_GETFD);
-    if (flags != -1 && ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC) != -1)
-      return fd;
-    SetLastError(error);
-    close(fd);
-  }
-  return fd;
-#elif defined(SOCK_CLOEXEC) && defined(HAVE_ACCEPT4)
+#if defined(SOCK_CLOEXEC) && defined(HAVE_ACCEPT4)
   int flags = SOCK_CLOEXEC;
   NativeSocket fd = llvm::sys::RetryAfterSignal(
       static_cast<NativeSocket>(-1), ::accept4, sockfd, addr, addrlen, flags);

lldb/source/Host/posix/HostInfoPosix.cpp

@@ -86,13 +86,6 @@ std::optional<std::string> HostInfoPosix::GetOSBuildString() {
   return std::string(un.release);
 }
 
-#ifdef __ANDROID__
-#include <android/api-level.h>
-#endif
-#if defined(__ANDROID_API__) && __ANDROID_API__ < 21
-#define USE_GETPWUID
-#endif
-
 namespace {
 class PosixUserIDResolver : public UserIDResolver {
 protected:
@@ -107,14 +100,6 @@ struct PasswdEntry {
 };
 
 static std::optional<PasswdEntry> GetPassword(id_t uid) {
-#ifdef USE_GETPWUID
-  // getpwuid_r is missing from android-9
-  // The caller should provide some thread safety by making sure no one calls
-  // this function concurrently, because using getpwuid is ultimately not
-  // thread-safe as we don't know who else might be calling it.
-  if (auto *user_info_ptr = ::getpwuid(uid))
-    return PasswdEntry{user_info_ptr->pw_name, user_info_ptr->pw_shell};
-#else
   struct passwd user_info;
   struct passwd *user_info_ptr = &user_info;
   char user_buffer[PATH_MAX];
@@ -124,7 +109,6 @@ static std::optional<PasswdEntry> GetPassword(id_t uid) {
       user_info_ptr) {
     return PasswdEntry{user_info_ptr->pw_name, user_info_ptr->pw_shell};
   }
-#endif
   return std::nullopt;
 }
 

lldb/source/Host/posix/ProcessLauncherPosixFork.cpp

@@ -25,13 +25,10 @@
 #include <sstream>
 
 #ifdef __ANDROID__
-#include <android/api-level.h>
 #define PT_TRACE_ME PTRACE_TRACEME
 #endif
 
-#if defined(__ANDROID_API__) && __ANDROID_API__ < 15
-#include <linux/personality.h>
-#elif defined(__linux__)
+#if defined(__linux__)
 #include <sys/personality.h>
 #endif