[libc][NFC] Rename "loader" to "startup".

Reviewed By: lntue

Differential Revision: https://reviews.llvm.org/D140049

8 files changed, 0 insertions, 599 deletions

diff --git a/libc/loader/CMakeLists.txt b/libc/loader/CMakeLists.txt
deleted file mode 100644
index b4bbe81c..0000000
--- a/libc/loader/CMakeLists.txt
+++ /dev/null
@@ -1,3 +0,0 @@
-if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})
-  add_subdirectory(${LIBC_TARGET_OS})
-endif()
diff --git a/libc/loader/linux/CMakeLists.txt b/libc/loader/linux/CMakeLists.txt
deleted file mode 100644
index 92ff896..0000000
--- a/libc/loader/linux/CMakeLists.txt
+++ /dev/null
@@ -1,96 +0,0 @@
-function(add_loader_object name)
-  cmake_parse_arguments(
-    "ADD_LOADER_OBJECT"
-    "ALIAS" # Option argument
-    "SRC"   # Single value arguments
-    "DEPENDS;COMPILE_OPTIONS" # Multi value arguments
-    ${ARGN}
-  )
-
-  get_fq_target_name(${name} fq_target_name)
-  get_fq_deps_list(fq_deps_list ${ADD_LOADER_OBJECT_DEPENDS})
-  if(ADD_LOADER_OBJECT_ALIAS)
-    list(LENGTH ADD_LOADER_OBJECT_DEPENDS deps_size)
-    if(NOT (${deps_size} EQUAL "1"))
-      message(FATAL_ERROR "A loader object alias should have exactly one dependency.")
-    endif()
-    list(GET ADD_LOADER_OBJECT_DEPENDS 0 dep)
-    get_fq_dep_name(fq_dep_name ${dep})
-
-    add_custom_target(${fq_target_name})
-    add_dependencies(${fq_target_name} ${fq_dep_name})
-    get_target_property(loader_object ${fq_dep_name} LOADER_OBJECT)
-    set_target_properties(
-      ${fq_target_name}
-      PROPERTIES
-        "TARGET_TYPE" "${OBJECT_LIBRARY_TARGET_TYPE}"
-        "LOADER_OBJECT" "${loader_object}"
-        "OBJECT_FILES" ""
-        "DEPS" "${fq_dep_name}"
-    )
-    return()
-  endif()
-
-  add_object_library(
-    ${name}.__objects__
-    SRCS ${ADD_LOADER_OBJECT_SRC}
-    DEPENDS ${ADD_LOADER_OBJECT_DEPENDS}
-    COMPILE_OPTIONS ${ADD_LOADER_OBJECT_COMPILE_OPTIONS}
-  )
-
-  set(objfile ${LIBC_BUILD_DIR}/lib/${name}.o)
-  add_custom_command(
-    OUTPUT ${objfile}
-    COMMAND cp $<TARGET_OBJECTS:${fq_target_name}.__objects__> ${objfile}
-    DEPENDS $<TARGET_OBJECTS:${fq_target_name}.__objects__>
-  )
-  add_custom_target(
-    ${fq_target_name}
-    DEPENDS ${objfile}
-  )
-  set_target_properties(
-    ${fq_target_name}
-    PROPERTIES
-      "TARGET_TYPE" "${OBJECT_LIBRARY_TARGET_TYPE}"
-      "LOADER_OBJECT" "${objfile}"
-      "OBJECT_FILES" ""
-      "DEPS" "${fq_target_name}.__objects__"
-  )
-endfunction()
-
-if(NOT (EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_ARCHITECTURE}))
-  message(STATUS "Skipping loader for target architecture ${LIBC_TARGET_ARCHITECTURE}")
-  return()
-endif()
-
-add_subdirectory(${LIBC_TARGET_ARCHITECTURE})
-
-add_loader_object(
-  crt1
-  ALIAS
-  DEPENDS
-    .${LIBC_TARGET_ARCHITECTURE}.crt1
-)
-
-add_loader_object(
-  crti
-  SRC
-    crti.cpp
-)
-
-add_loader_object(
-  crtn
-  SRC
-    crtn.cpp
-)
-
-add_custom_target(libc-startup)
-set(startup_components crt1 crti crtn)
-foreach(target IN LISTS startup_components)
-  set(fq_target_name libc.loader.linux.${target})
-  add_dependencies(libc-startup ${fq_target_name})
-  get_target_property(loader_object ${fq_target_name} LOADER_OBJECT)
-  install(FILES ${loader_object}
-          DESTINATION ${CMAKE_INSTALL_LIBDIR}
-          COMPONENT ${LIBC_COMPONENT})
-endforeach()
diff --git a/libc/loader/linux/aarch64/CMakeLists.txt b/libc/loader/linux/aarch64/CMakeLists.txt
deleted file mode 100644
index 054df0b..0000000
--- a/libc/loader/linux/aarch64/CMakeLists.txt
+++ /dev/null
@@ -1,16 +0,0 @@
-add_loader_object(
-  crt1
-  SRC
-    start.cpp
-  DEPENDS
-    libc.config.linux.app_h
-    libc.include.sys_mman
-    libc.include.sys_syscall
-    libc.src.__support.OSUtil.osutil
-    libc.src.stdlib.exit
-    libc.src.stdlib.atexit
-    libc.src.string.memory_utils.memcpy_implementation
-  COMPILE_OPTIONS
-    -fno-omit-frame-pointer
-    -ffreestanding # To avoid compiler warnings about calling the main function.
-)
diff --git a/libc/loader/linux/aarch64/start.cpp b/libc/loader/linux/aarch64/start.cpp
deleted file mode 100644
index b02ea7d..0000000
--- a/libc/loader/linux/aarch64/start.cpp
+++ /dev/null
@@ -1,230 +0,0 @@
-//===-- Implementation of crt for aarch64 ---------------------------------===//
-//
-// 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
-//
-//===----------------------------------------------------------------------===//
-
-#include "config/linux/app.h"
-#include "src/__support/OSUtil/syscall.h"
-#include "src/__support/threads/thread.h"
-#include "src/stdlib/atexit.h"
-#include "src/stdlib/exit.h"
-#include "src/string/memory_utils/memcpy_implementations.h"
-
-#include <arm_acle.h>
-
-#include <linux/auxvec.h>
-#include <linux/elf.h>
-#include <stdint.h>
-#include <sys/mman.h>
-#include <sys/syscall.h>
-#include <unistd.h>
-
-extern "C" int main(int, char **, char **);
-
-// Source documentation:
-// https://github.com/ARM-software/abi-aa/tree/main/sysvabi64
-
-namespace __llvm_libc {
-
-#ifdef SYS_mmap2
-static constexpr long MMAP_SYSCALL_NUMBER = SYS_mmap2;
-#elif SYS_mmap
-static constexpr long MMAP_SYSCALL_NUMBER = SYS_mmap;
-#else
-#error "Target platform does not have SYS_mmap or SYS_mmap2 defined"
-#endif
-
-AppProperties app;
-
-static ThreadAttributes main_thread_attrib;
-
-void init_tls(TLSDescriptor &tls_descriptor) {
-  if (app.tls.size == 0) {
-    tls_descriptor.size = 0;
-    tls_descriptor.tp = 0;
-    return;
-  }
-
-  // aarch64 follows the variant 1 TLS layout:
-  //
-  // 1. First entry is the dynamic thread vector pointer
-  // 2. Second entry is a 8-byte reserved word.
-  // 3. Padding for alignment.
-  // 4. The TLS data from the ELF image.
-  //
-  // The thread pointer points to the first entry.
-
-  const uintptr_t size_of_pointers = 2 * sizeof(uintptr_t);
-  uintptr_t padding = 0;
-  const uintptr_t ALIGNMENT_MASK = app.tls.align - 1;
-  uintptr_t diff = size_of_pointers & ALIGNMENT_MASK;
-  if (diff != 0)
-    padding += (ALIGNMENT_MASK - diff) + 1;
-
-  uintptr_t alloc_size = size_of_pointers + padding + app.tls.size;
-
-  // We cannot call the mmap function here as the functions set errno on
-  // failure. Since errno is implemented via a thread local variable, we cannot
-  // use errno before TLS is setup.
-  long mmap_ret_val = __llvm_libc::syscall_impl(
-      MMAP_SYSCALL_NUMBER, nullptr, alloc_size, PROT_READ | PROT_WRITE,
-      MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
-  // We cannot check the return value with MAP_FAILED as that is the return
-  // of the mmap function and not the mmap syscall.
-  if (mmap_ret_val < 0 && static_cast<uintptr_t>(mmap_ret_val) > -app.pageSize)
-    __llvm_libc::syscall_impl(SYS_exit, 1);
-  uintptr_t thread_ptr = uintptr_t(reinterpret_cast<uintptr_t *>(mmap_ret_val));
-  uintptr_t tls_addr = thread_ptr + size_of_pointers + padding;
-  __llvm_libc::inline_memcpy(reinterpret_cast<char *>(tls_addr),
-                             reinterpret_cast<const char *>(app.tls.address),
-                             app.tls.init_size);
-  tls_descriptor.size = alloc_size;
-  tls_descriptor.addr = thread_ptr;
-  tls_descriptor.tp = thread_ptr;
-}
-
-void cleanup_tls(uintptr_t addr, uintptr_t size) {
-  if (size == 0)
-    return;
-  __llvm_libc::syscall_impl(SYS_munmap, addr, size);
-}
-
-static void set_thread_ptr(uintptr_t val) { __arm_wsr64("tpidr_el0", val); }
-
-using InitCallback = void(int, char **, char **);
-using FiniCallback = void(void);
-
-extern "C" {
-// These arrays are present in the .init_array and .fini_array sections.
-// The symbols are inserted by linker when it sees references to them.
-extern uintptr_t __preinit_array_start[];
-extern uintptr_t __preinit_array_end[];
-extern uintptr_t __init_array_start[];
-extern uintptr_t __init_array_end[];
-extern uintptr_t __fini_array_start[];
-extern uintptr_t __fini_array_end[];
-}
-
-static void call_init_array_callbacks(int argc, char **argv, char **env) {
-  size_t preinit_array_size = __preinit_array_end - __preinit_array_start;
-  for (size_t i = 0; i < preinit_array_size; ++i)
-    reinterpret_cast<InitCallback *>(__preinit_array_start[i])(argc, argv, env);
-  size_t init_array_size = __init_array_end - __init_array_start;
-  for (size_t i = 0; i < init_array_size; ++i)
-    reinterpret_cast<InitCallback *>(__init_array_start[i])(argc, argv, env);
-}
-
-static void call_fini_array_callbacks() {
-  size_t fini_array_size = __fini_array_end - __fini_array_start;
-  for (size_t i = fini_array_size; i > 0; --i)
-    reinterpret_cast<FiniCallback *>(__fini_array_start[i - 1])();
-}
-
-} // namespace __llvm_libc
-
-using __llvm_libc::app;
-
-// TODO: Would be nice to use the aux entry structure from elf.h when available.
-struct AuxEntry {
-  uint64_t type;
-  uint64_t value;
-};
-
-__attribute__((noinline)) static void do_start() {
-  auto tid = __llvm_libc::syscall_impl(SYS_gettid);
-  if (tid <= 0)
-    __llvm_libc::syscall_impl(SYS_exit, 1);
-  __llvm_libc::main_thread_attrib.tid = tid;
-
-  // After the argv array, is a 8-byte long NULL value before the array of env
-  // values. The end of the env values is marked by another 8-byte long NULL
-  // value. We step over it (the "+ 1" below) to get to the env values.
-  uint64_t *env_ptr = app.args->argv + app.args->argc + 1;
-  uint64_t *env_end_marker = env_ptr;
-  app.envPtr = env_ptr;
-  while (*env_end_marker)
-    ++env_end_marker;
-
-  // Initialize the POSIX global declared in unistd.h
-  environ = reinterpret_cast<char **>(env_ptr);
-
-  // After the env array, is the aux-vector. The end of the aux-vector is
-  // denoted by an AT_NULL entry.
-  Elf64_Phdr *programHdrTable = nullptr;
-  uintptr_t programHdrCount;
-  for (AuxEntry *aux_entry = reinterpret_cast<AuxEntry *>(env_end_marker + 1);
-       aux_entry->type != AT_NULL; ++aux_entry) {
-    switch (aux_entry->type) {
-    case AT_PHDR:
-      programHdrTable = reinterpret_cast<Elf64_Phdr *>(aux_entry->value);
-      break;
-    case AT_PHNUM:
-      programHdrCount = aux_entry->value;
-      break;
-    case AT_PAGESZ:
-      app.pageSize = aux_entry->value;
-      break;
-    default:
-      break; // TODO: Read other useful entries from the aux vector.
-    }
-  }
-
-  app.tls.size = 0;
-  for (uintptr_t i = 0; i < programHdrCount; ++i) {
-    Elf64_Phdr *phdr = programHdrTable + i;
-    if (phdr->p_type != PT_TLS)
-      continue;
-    // TODO: p_vaddr value has to be adjusted for static-pie executables.
-    app.tls.address = phdr->p_vaddr;
-    app.tls.size = phdr->p_memsz;
-    app.tls.init_size = phdr->p_filesz;
-    app.tls.align = phdr->p_align;
-  }
-
-  __llvm_libc::TLSDescriptor tls;
-  __llvm_libc::init_tls(tls);
-  if (tls.size != 0)
-    __llvm_libc::set_thread_ptr(tls.tp);
-
-  __llvm_libc::self.attrib = &__llvm_libc::main_thread_attrib;
-  __llvm_libc::main_thread_attrib.atexit_callback_mgr =
-      __llvm_libc::internal::get_thread_atexit_callback_mgr();
-
-  // We want the fini array callbacks to be run after other atexit
-  // callbacks are run. So, we register them before running the init
-  // array callbacks as they can potentially register their own atexit
-  // callbacks.
-  __llvm_libc::atexit(&__llvm_libc::call_fini_array_callbacks);
-
-  __llvm_libc::call_init_array_callbacks(
-      app.args->argc, reinterpret_cast<char **>(app.args->argv),
-      reinterpret_cast<char **>(env_ptr));
-
-  int retval = main(app.args->argc, reinterpret_cast<char **>(app.args->argv),
-                    reinterpret_cast<char **>(env_ptr));
-
-  // TODO: TLS cleanup should be done after all other atexit callbacks
-  // are run. So, register a cleanup callback for it with atexit before
-  // everything else.
-  __llvm_libc::cleanup_tls(tls.addr, tls.size);
-  __llvm_libc::exit(retval);
-}
-
-extern "C" void _start() {
-  // Skip the Frame Pointer and the Link Register
-  // https://github.com/ARM-software/abi-aa/blob/main/aapcs64/aapcs64.rst
-  // Section 6.2.3. Note that this only works if the current function
-  // is not using any callee-saved registers (x19 to x28). If the
-  // function uses such registers, then their value is pushed on to the
-  // stack before the frame pointer an link register values. That breaks
-  // the assumption that stepping over the frame pointer and link register
-  // will take us to the previous stack pointer. That is the reason why the
-  // actual business logic of the startup code is pushed into a non-inline
-  // function do_start so that this function is free of any stack usage.
-  app.args = reinterpret_cast<__llvm_libc::Args *>(
-      reinterpret_cast<uintptr_t *>(__builtin_frame_address(0)) + 2);
-  do_start();
-}
diff --git a/libc/loader/linux/crti.cpp b/libc/loader/linux/crti.cpp
deleted file mode 100644
index e69de29..0000000
--- a/libc/loader/linux/crti.cpp
+++ /dev/null
diff --git a/libc/loader/linux/crtn.cpp b/libc/loader/linux/crtn.cpp
deleted file mode 100644
index e69de29..0000000
--- a/libc/loader/linux/crtn.cpp
+++ /dev/null
diff --git a/libc/loader/linux/x86_64/CMakeLists.txt b/libc/loader/linux/x86_64/CMakeLists.txt
deleted file mode 100644
index f62ad0a..0000000
--- a/libc/loader/linux/x86_64/CMakeLists.txt
+++ /dev/null
@@ -1,20 +0,0 @@
-add_loader_object(
-  crt1
-  SRC
-    start.cpp
-  DEPENDS
-    libc.config.linux.app_h
-    libc.include.sys_mman
-    libc.include.sys_syscall
-    libc.include.unistd
-    libc.src.__support.threads.thread
-    libc.src.__support.OSUtil.osutil
-    libc.src.stdlib.exit
-    libc.src.stdlib.atexit
-    libc.src.string.memory_utils.memcpy_implementation
-    libc.src.unistd.environ
-  COMPILE_OPTIONS
-    -fno-omit-frame-pointer
-    -ffreestanding # To avoid compiler warnings about calling the main function.
-    -fno-builtin
-)
diff --git a/libc/loader/linux/x86_64/start.cpp b/libc/loader/linux/x86_64/start.cpp
deleted file mode 100644
index 6ddb344..0000000
--- a/libc/loader/linux/x86_64/start.cpp
+++ /dev/null
@@ -1,234 +0,0 @@
-//===-- Implementation of crt for x86_64 ----------------------------------===//
-//
-// 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
-//
-//===----------------------------------------------------------------------===//
-
-#include "config/linux/app.h"
-#include "src/__support/OSUtil/syscall.h"
-#include "src/__support/threads/thread.h"
-#include "src/stdlib/atexit.h"
-#include "src/stdlib/exit.h"
-#include "src/string/memory_utils/memcpy_implementations.h"
-
-#include <asm/prctl.h>
-#include <linux/auxvec.h>
-#include <linux/elf.h>
-#include <stdint.h>
-#include <sys/mman.h>
-#include <sys/syscall.h>
-#include <unistd.h>
-
-extern "C" int main(int, char **, char **);
-
-namespace __llvm_libc {
-
-#ifdef SYS_mmap2
-static constexpr long mmapSyscallNumber = SYS_mmap2;
-#elif SYS_mmap
-static constexpr long mmapSyscallNumber = SYS_mmap;
-#else
-#error "Target platform does not have SYS_mmap or SYS_mmap2 defined"
-#endif
-
-AppProperties app;
-
-static ThreadAttributes main_thread_attrib;
-
-// TODO: The function is x86_64 specific. Move it to config/linux/app.h
-// and generalize it. Also, dynamic loading is not handled currently.
-void init_tls(TLSDescriptor &tls_descriptor) {
-  if (app.tls.size == 0) {
-    tls_descriptor.size = 0;
-    tls_descriptor.tp = 0;
-    return;
-  }
-
-  // We will assume the alignment is always a power of two.
-  uintptr_t tlsSize = app.tls.size & -app.tls.align;
-  if (tlsSize != app.tls.size)
-    tlsSize += app.tls.align;
-
-  // Per the x86_64 TLS ABI, the entry pointed to by the thread pointer is the
-  // address of the TLS block. So, we add more size to accomodate this address
-  // entry.
-  uintptr_t tlsSizeWithAddr = tlsSize + sizeof(uintptr_t);
-
-  // We cannot call the mmap function here as the functions set errno on
-  // failure. Since errno is implemented via a thread local variable, we cannot
-  // use errno before TLS is setup.
-  long mmapRetVal = __llvm_libc::syscall_impl(
-      mmapSyscallNumber, nullptr, tlsSizeWithAddr, PROT_READ | PROT_WRITE,
-      MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
-  // We cannot check the return value with MAP_FAILED as that is the return
-  // of the mmap function and not the mmap syscall.
-  if (mmapRetVal < 0 && static_cast<uintptr_t>(mmapRetVal) > -app.pageSize)
-    __llvm_libc::syscall_impl(SYS_exit, 1);
-  uintptr_t *tlsAddr = reinterpret_cast<uintptr_t *>(mmapRetVal);
-
-  // x86_64 TLS faces down from the thread pointer with the first entry
-  // pointing to the address of the first real TLS byte.
-  uintptr_t endPtr = reinterpret_cast<uintptr_t>(tlsAddr) + tlsSize;
-  *reinterpret_cast<uintptr_t *>(endPtr) = endPtr;
-
-  __llvm_libc::inline_memcpy(reinterpret_cast<char *>(tlsAddr),
-                             reinterpret_cast<const char *>(app.tls.address),
-                             app.tls.init_size);
-
-  tls_descriptor = {tlsSizeWithAddr, uintptr_t(tlsAddr), endPtr};
-  return;
-}
-
-void cleanup_tls(uintptr_t addr, uintptr_t size) {
-  if (size == 0)
-    return;
-  __llvm_libc::syscall_impl(SYS_munmap, addr, size);
-}
-
-// Sets the thread pointer to |val|. Returns true on success, false on failure.
-static bool set_thread_ptr(uintptr_t val) {
-  return __llvm_libc::syscall_impl(SYS_arch_prctl, ARCH_SET_FS, val) == -1
-             ? false
-             : true;
-}
-
-using InitCallback = void(int, char **, char **);
-using FiniCallback = void(void);
-
-extern "C" {
-// These arrays are present in the .init_array and .fini_array sections.
-// The symbols are inserted by linker when it sees references to them.
-extern uintptr_t __preinit_array_start[];
-extern uintptr_t __preinit_array_end[];
-extern uintptr_t __init_array_start[];
-extern uintptr_t __init_array_end[];
-extern uintptr_t __fini_array_start[];
-extern uintptr_t __fini_array_end[];
-}
-
-static void call_init_array_callbacks(int argc, char **argv, char **env) {
-  size_t preinit_array_size = __preinit_array_end - __preinit_array_start;
-  for (size_t i = 0; i < preinit_array_size; ++i)
-    reinterpret_cast<InitCallback *>(__preinit_array_start[i])(argc, argv, env);
-  size_t init_array_size = __init_array_end - __init_array_start;
-  for (size_t i = 0; i < init_array_size; ++i)
-    reinterpret_cast<InitCallback *>(__init_array_start[i])(argc, argv, env);
-}
-
-static void call_fini_array_callbacks() {
-  size_t fini_array_size = __fini_array_end - __fini_array_start;
-  for (size_t i = fini_array_size; i > 0; --i)
-    reinterpret_cast<FiniCallback *>(__fini_array_start[i - 1])();
-}
-
-} // namespace __llvm_libc
-
-using __llvm_libc::app;
-
-// TODO: Would be nice to use the aux entry structure from elf.h when available.
-struct AuxEntry {
-  uint64_t type;
-  uint64_t value;
-};
-
-extern "C" void _start() {
-  // This TU is compiled with -fno-omit-frame-pointer. Hence, the previous value
-  // of the base pointer is pushed on to the stack. So, we step over it (the
-  // "+ 1" below) to get to the args.
-  app.args = reinterpret_cast<__llvm_libc::Args *>(
-      reinterpret_cast<uintptr_t *>(__builtin_frame_address(0)) + 1);
-
-  // The x86_64 ABI requires that the stack pointer is aligned to a 16-byte
-  // boundary. We align it here but we cannot use any local variables created
-  // before the following alignment. Best would be to not create any local
-  // variables before the alignment. Also, note that we are aligning the stack
-  // downwards as the x86_64 stack grows downwards. This ensures that we don't
-  // tread on argc, argv etc.
-  // NOTE: Compiler attributes for alignment do not help here as the stack
-  // pointer on entry to this _start function is controlled by the OS. In fact,
-  // compilers can generate code assuming the alignment as required by the ABI.
-  // If the stack pointers as setup by the OS are already aligned, then the
-  // following code is a NOP.
-  __asm__ __volatile__("andq $0xfffffffffffffff0, %%rsp\n\t" ::: "%rsp");
-  __asm__ __volatile__("andq $0xfffffffffffffff0, %%rbp\n\t" ::: "%rbp");
-
-  auto tid = __llvm_libc::syscall_impl(SYS_gettid);
-  if (tid <= 0)
-    __llvm_libc::syscall_impl(SYS_exit, 1);
-  __llvm_libc::main_thread_attrib.tid = tid;
-
-  // After the argv array, is a 8-byte long NULL value before the array of env
-  // values. The end of the env values is marked by another 8-byte long NULL
-  // value. We step over it (the "+ 1" below) to get to the env values.
-  uint64_t *env_ptr = app.args->argv + app.args->argc + 1;
-  uint64_t *env_end_marker = env_ptr;
-  app.envPtr = env_ptr;
-  while (*env_end_marker)
-    ++env_end_marker;
-
-  // Initialize the POSIX global declared in unistd.h
-  environ = reinterpret_cast<char **>(env_ptr);
-
-  // After the env array, is the aux-vector. The end of the aux-vector is
-  // denoted by an AT_NULL entry.
-  Elf64_Phdr *programHdrTable = nullptr;
-  uintptr_t programHdrCount;
-  for (AuxEntry *aux_entry = reinterpret_cast<AuxEntry *>(env_end_marker + 1);
-       aux_entry->type != AT_NULL; ++aux_entry) {
-    switch (aux_entry->type) {
-    case AT_PHDR:
-      programHdrTable = reinterpret_cast<Elf64_Phdr *>(aux_entry->value);
-      break;
-    case AT_PHNUM:
-      programHdrCount = aux_entry->value;
-      break;
-    case AT_PAGESZ:
-      app.pageSize = aux_entry->value;
-      break;
-    default:
-      break; // TODO: Read other useful entries from the aux vector.
-    }
-  }
-
-  app.tls.size = 0;
-  for (uintptr_t i = 0; i < programHdrCount; ++i) {
-    Elf64_Phdr *phdr = programHdrTable + i;
-    if (phdr->p_type != PT_TLS)
-      continue;
-    // TODO: p_vaddr value has to be adjusted for static-pie executables.
-    app.tls.address = phdr->p_vaddr;
-    app.tls.size = phdr->p_memsz;
-    app.tls.init_size = phdr->p_filesz;
-    app.tls.align = phdr->p_align;
-  }
-
-  __llvm_libc::TLSDescriptor tls;
-  __llvm_libc::init_tls(tls);
-  if (tls.size != 0 && !__llvm_libc::set_thread_ptr(tls.tp))
-    __llvm_libc::syscall_impl(SYS_exit, 1);
-
-  __llvm_libc::self.attrib = &__llvm_libc::main_thread_attrib;
-  __llvm_libc::main_thread_attrib.atexit_callback_mgr =
-      __llvm_libc::internal::get_thread_atexit_callback_mgr();
-
-  // We want the fini array callbacks to be run after other atexit
-  // callbacks are run. So, we register them before running the init
-  // array callbacks as they can potentially register their own atexit
-  // callbacks.
-  __llvm_libc::atexit(&__llvm_libc::call_fini_array_callbacks);
-
-  __llvm_libc::call_init_array_callbacks(
-      app.args->argc, reinterpret_cast<char **>(app.args->argv),
-      reinterpret_cast<char **>(env_ptr));
-
-  int retval = main(app.args->argc, reinterpret_cast<char **>(app.args->argv),
-                    reinterpret_cast<char **>(env_ptr));
-
-  // TODO: TLS cleanup should be done after all other atexit callbacks
-  // are run. So, register a cleanup callback for it with atexit before
-  // everything else.
-  __llvm_libc::cleanup_tls(tls.addr, tls.size);
-  __llvm_libc::exit(retval);
-}