[libc] Added static casts to fix implicit conversion warnings in 32-bit systems

This patch fixes:

randomness.h and getauxval.cpp were passing ssize_t as size_t
kernel_statx.h was assigning an uint64_t to uintptr_t
fopencookie.cpp was trying to create a FileIOResult using ssize_t but the constructor expected a size_t
thread.h was trying to call free_stack (which takes a size_t) with an unsigned long long. free_stack does the calculations using uintptr_t, so I changed the passing values to size_t

Author: mikhailramalho

libc/src/__support/HashTable/randomness.h

@@ -36,7 +36,7 @@ LIBC_INLINE uint64_t next_random_seed() {
     entropy[1] = reinterpret_cast<uint64_t>(&state);
 #if defined(LIBC_HASHTABLE_USE_GETRANDOM)
     int errno_backup = libc_errno;
-    ssize_t count = sizeof(entropy);
+    size_t count = sizeof(entropy);
     uint8_t *buffer = reinterpret_cast<uint8_t *>(entropy);
     while (count > 0) {
       ssize_t len = getrandom(buffer, count, 0);

libc/src/__support/threads/thread.h

@@ -102,11 +102,11 @@ struct alignas(STACK_ALIGNMENT) ThreadAttributes {
   //          exits. It will clean up the thread resources once the thread
   //          exits.
   cpp::Atomic<uint32_t> detach_state;
-  void *stack;                  // Pointer to the thread stack
-  unsigned long long stacksize; // Size of the stack
-  unsigned long long guardsize; // Guard size on stack
-  uintptr_t tls;                // Address to the thread TLS memory
-  uintptr_t tls_size;           // The size of area pointed to by |tls|.
+  void *stack;               // Pointer to the thread stack
+  size_t stacksize;          // Size of the stack
+  size_t guardsize;          // Guard size on stack
+  uintptr_t tls;             // Address to the thread TLS memory
+  uintptr_t tls_size;        // The size of area pointed to by |tls|.
   unsigned char owned_stack; // Indicates if the thread owns this stack memory
   pid_t tid;
   ThreadStyle style;

libc/src/stdio/fopencookie.cpp

@@ -43,16 +43,16 @@ FileIOResult CookieFile::cookie_write(File *f, const void *data, size_t size) {
   auto cookie_file = reinterpret_cast<CookieFile *>(f);
   if (cookie_file->ops.write == nullptr)
     return 0;
-  return cookie_file->ops.write(cookie_file->cookie,
-                                reinterpret_cast<const char *>(data), size);
+  return static_cast<size_t>(cookie_file->ops.write(
+      cookie_file->cookie, reinterpret_cast<const char *>(data), size));
 }
 
 FileIOResult CookieFile::cookie_read(File *f, void *data, size_t size) {
   auto cookie_file = reinterpret_cast<CookieFile *>(f);
   if (cookie_file->ops.read == nullptr)
     return 0;
-  return cookie_file->ops.read(cookie_file->cookie,
-                               reinterpret_cast<char *>(data), size);
+  return static_cast<size_t>(cookie_file->ops.read(
+      cookie_file->cookie, reinterpret_cast<char *>(data), size));
 }
 
 ErrorOr<off_t> CookieFile::cookie_seek(File *f, off_t offset, int whence) {

libc/src/sys/auxv/linux/getauxval.cpp

@@ -155,7 +155,7 @@ static void initialize_auxv_once(void) {
 
 static AuxEntry read_entry(int fd) {
   AuxEntry buf;
-  ssize_t size = sizeof(AuxEntry);
+  size_t size = sizeof(AuxEntry);
   char *ptr = reinterpret_cast<char *>(&buf);
   while (size > 0) {
     ssize_t ret = read(fd, ptr, size);

libc/src/sys/stat/linux/kernel_statx.h

@@ -80,7 +80,7 @@ LIBC_INLINE int statx(int dirfd, const char *__restrict path, int flags,
     return -ret;
 
   statbuf->st_dev = MKDEV(xbuf.stx_dev_major, xbuf.stx_dev_minor);
-  statbuf->st_ino = xbuf.stx_ino;
+  statbuf->st_ino = static_cast<decltype(statbuf->st_ino)>(xbuf.stx_ino);
   statbuf->st_mode = xbuf.stx_mode;
   statbuf->st_nlink = xbuf.stx_nlink;
   statbuf->st_uid = xbuf.stx_uid;
@@ -94,7 +94,8 @@ LIBC_INLINE int statx(int dirfd, const char *__restrict path, int flags,
   statbuf->st_ctim.tv_sec = xbuf.stx_ctime.tv_sec;
   statbuf->st_ctim.tv_nsec = xbuf.stx_ctime.tv_nsec;
   statbuf->st_blksize = xbuf.stx_blksize;
-  statbuf->st_blocks = xbuf.stx_blocks;
+  statbuf->st_blocks =
+      static_cast<decltype(statbuf->st_blocks)>(xbuf.stx_blocks);
 
   return 0;
 }