[libc][NFC] unify startup library's code style with the rest (#74041)

This PR unifies the startup library's code style with the rest of libc.

Author: SchrodingerZhu

libc/config/linux/app.h

@@ -69,15 +69,15 @@ struct Args {
 // Data structure which captures properties of a linux application.
 struct AppProperties {
   // Page size used for the application.
-  uintptr_t pageSize;
+  uintptr_t page_size;
 
   Args *args;
 
   // The properties of an application's TLS image.
   TLSImage tls;
 
   // Environment data.
-  EnvironType *envPtr;
+  EnvironType *env_ptr;
 };
 
 extern AppProperties app;

libc/src/stdlib/getenv.cpp

@@ -16,7 +16,7 @@
 namespace LIBC_NAMESPACE {
 
 LLVM_LIBC_FUNCTION(char *, getenv, (const char *name)) {
-  char **env_ptr = reinterpret_cast<char **>(LIBC_NAMESPACE::app.envPtr);
+  char **env_ptr = reinterpret_cast<char **>(LIBC_NAMESPACE::app.env_ptr);
 
   if (name == nullptr || env_ptr == nullptr)
     return nullptr;

libc/startup/linux/aarch64/start.cpp

@@ -74,7 +74,7 @@ void init_tls(TLSDescriptor &tls_descriptor) {
       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)
+  if (mmap_ret_val < 0 && static_cast<uintptr_t>(mmap_ret_val) > -app.page_size)
     LIBC_NAMESPACE::syscall_impl<long>(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;
@@ -144,7 +144,7 @@ __attribute__((noinline)) static void do_start() {
   // 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;
+  app.env_ptr = env_ptr;
   while (*env_end_marker)
     ++env_end_marker;
 
@@ -153,28 +153,28 @@ __attribute__((noinline)) static void do_start() {
 
   // 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;
+  Elf64_Phdr *program_hdr_table = nullptr;
+  uintptr_t program_hdr_count;
   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);
+      program_hdr_table = reinterpret_cast<Elf64_Phdr *>(aux_entry->value);
       break;
     case AT_PHNUM:
-      programHdrCount = aux_entry->value;
+      program_hdr_count = aux_entry->value;
       break;
     case AT_PAGESZ:
-      app.pageSize = aux_entry->value;
+      app.page_size = 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;
+  for (uintptr_t i = 0; i < program_hdr_count; ++i) {
+    Elf64_Phdr *phdr = program_hdr_table + i;
     if (phdr->p_type != PT_TLS)
       continue;
     // TODO: p_vaddr value has to be adjusted for static-pie executables.

libc/startup/linux/riscv/start.cpp

@@ -61,7 +61,7 @@ void init_tls(TLSDescriptor &tls_descriptor) {
       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)
+  if (mmap_ret_val < 0 && static_cast<uintptr_t>(mmap_ret_val) > -app.page_size)
     LIBC_NAMESPACE::syscall_impl<long>(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;
@@ -147,7 +147,7 @@ __attribute__((noinline)) static void do_start() {
   // value. We step over it (the "+ 1" below) to get to the env values.
   LIBC_NAMESPACE::ArgVEntryType *env_ptr = app.args->argv + app.args->argc + 1;
   LIBC_NAMESPACE::ArgVEntryType *env_end_marker = env_ptr;
-  app.envPtr = env_ptr;
+  app.env_ptr = env_ptr;
   while (*env_end_marker)
     ++env_end_marker;
 
@@ -156,28 +156,28 @@ __attribute__((noinline)) static void do_start() {
 
   // After the env array, is the aux-vector. The end of the aux-vector is
   // denoted by an AT_NULL entry.
-  PgrHdrTableType *programHdrTable = nullptr;
-  uintptr_t programHdrCount;
+  PgrHdrTableType *program_hdr_table = nullptr;
+  uintptr_t program_hdr_count;
   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<PgrHdrTableType *>(aux_entry->value);
+      program_hdr_table = reinterpret_cast<PgrHdrTableType *>(aux_entry->value);
       break;
     case AT_PHNUM:
-      programHdrCount = aux_entry->value;
+      program_hdr_count = aux_entry->value;
       break;
     case AT_PAGESZ:
-      app.pageSize = aux_entry->value;
+      app.page_size = 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) {
-    PgrHdrTableType *phdr = programHdrTable + i;
+  for (uintptr_t i = 0; i < program_hdr_count; ++i) {
+    PgrHdrTableType *phdr = program_hdr_table + i;
     if (phdr->p_type != PT_TLS)
       continue;
     // TODO: p_vaddr value has to be adjusted for static-pie executables.

libc/startup/linux/x86_64/start.cpp

@@ -33,9 +33,9 @@ extern "C" void __stack_chk_fail() {
 namespace LIBC_NAMESPACE {
 
 #ifdef SYS_mmap2
-static constexpr long mmapSyscallNumber = SYS_mmap2;
+static constexpr long MMAP_SYSCALL_NUMBER = SYS_mmap2;
 #elif SYS_mmap
-static constexpr long mmapSyscallNumber = SYS_mmap;
+static constexpr long MMAP_SYSCALL_NUMBER = SYS_mmap;
 #else
 #error "mmap and mmap2 syscalls not available."
 #endif
@@ -54,49 +54,50 @@ void init_tls(TLSDescriptor &tls_descriptor) {
   }
 
   // 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;
+  uintptr_t tls_size = app.tls.size & -app.tls.align;
+  if (tls_size != app.tls.size)
+    tls_size += 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.
   // We also need to include space for the stack canary. The canary is at
   // offset 0x28 (40) and is of size uintptr_t.
-  uintptr_t tlsSizeWithAddr = tlsSize + sizeof(uintptr_t) + 40;
+  uintptr_t tls_size_with_addr = tls_size + sizeof(uintptr_t) + 40;
 
   // 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 = LIBC_NAMESPACE::syscall_impl<long>(
-      mmapSyscallNumber, nullptr, tlsSizeWithAddr, PROT_READ | PROT_WRITE,
+  long mmap_retval = LIBC_NAMESPACE::syscall_impl<long>(
+      MMAP_SYSCALL_NUMBER, nullptr, tls_size_with_addr, 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)
+  if (mmap_retval < 0 && static_cast<uintptr_t>(mmap_retval) > -app.page_size)
     LIBC_NAMESPACE::syscall_impl<long>(SYS_exit, 1);
-  uintptr_t *tlsAddr = reinterpret_cast<uintptr_t *>(mmapRetVal);
+  uintptr_t *tls_addr = reinterpret_cast<uintptr_t *>(mmap_retval);
 
   // 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;
+  uintptr_t end_ptr = reinterpret_cast<uintptr_t>(tls_addr) + tls_size;
+  *reinterpret_cast<uintptr_t *>(end_ptr) = end_ptr;
 
-  LIBC_NAMESPACE::inline_memcpy(reinterpret_cast<char *>(tlsAddr),
+  LIBC_NAMESPACE::inline_memcpy(reinterpret_cast<char *>(tls_addr),
                                 reinterpret_cast<const char *>(app.tls.address),
                                 app.tls.init_size);
-  uintptr_t *stackGuardAddr = reinterpret_cast<uintptr_t *>(endPtr + 40);
+  uintptr_t *stack_guard_addr = reinterpret_cast<uintptr_t *>(end_ptr + 40);
   // Setting the stack guard to a random value.
   // We cannot call the get_random function here as the function sets errno on
   // failure. Since errno is implemented via a thread local variable, we cannot
   // use errno before TLS is setup.
-  ssize_t stackGuardRetVal = LIBC_NAMESPACE::syscall_impl<ssize_t>(
-      SYS_getrandom, reinterpret_cast<long>(stackGuardAddr), sizeof(uint64_t),
+  ssize_t stack_guard_retval = LIBC_NAMESPACE::syscall_impl<ssize_t>(
+      SYS_getrandom, reinterpret_cast<long>(stack_guard_addr), sizeof(uint64_t),
       0);
-  if (stackGuardRetVal < 0)
+  if (stack_guard_retval < 0)
     LIBC_NAMESPACE::syscall_impl(SYS_exit, 1);
 
-  tls_descriptor = {tlsSizeWithAddr, uintptr_t(tlsAddr), endPtr};
+  tls_descriptor = {tls_size_with_addr, reinterpret_cast<uintptr_t>(tls_addr),
+                    end_ptr};
   return;
 }
 
@@ -181,7 +182,7 @@ extern "C" void _start() {
   // 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;
+  app.env_ptr = env_ptr;
   while (*env_end_marker)
     ++env_end_marker;
 
@@ -190,28 +191,28 @@ extern "C" void _start() {
 
   // 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;
+  Elf64_Phdr *program_hdr_table = nullptr;
+  uintptr_t program_hdr_count = 0;
   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);
+      program_hdr_table = reinterpret_cast<Elf64_Phdr *>(aux_entry->value);
       break;
     case AT_PHNUM:
-      programHdrCount = aux_entry->value;
+      program_hdr_count = aux_entry->value;
       break;
     case AT_PAGESZ:
-      app.pageSize = aux_entry->value;
+      app.page_size = 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;
+  for (uintptr_t i = 0; i < program_hdr_count; ++i) {
+    Elf64_Phdr *phdr = program_hdr_table + i;
     if (phdr->p_type != PT_TLS)
       continue;
     // TODO: p_vaddr value has to be adjusted for static-pie executables.