[libc][cleanup] Fix most conversion warnings

This patch is large, but is almost entirely just adding casts to calls
to syscall_impl. Much of the work was done programatically, with human
checking when the syntax or types got confusing.

Reviewed By: mcgrathr

Differential Revision: https://reviews.llvm.org/D156950

3 files changed, 31 insertions, 25 deletions

diff --git a/libc/startup/linux/aarch64/start.cpp b/libc/startup/linux/aarch64/start.cpp
index 67253bc..7b94ae6 100644
--- a/libc/startup/linux/aarch64/start.cpp
+++ b/libc/startup/linux/aarch64/start.cpp
@@ -69,13 +69,13 @@ void init_tls(TLSDescriptor &tls_descriptor) {
   // 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(
+  long mmap_ret_val = __llvm_libc::syscall_impl<long>(
       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);
+    __llvm_libc::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;
   __llvm_libc::inline_memcpy(reinterpret_cast<char *>(tls_addr),
@@ -89,7 +89,7 @@ void init_tls(TLSDescriptor &tls_descriptor) {
 void cleanup_tls(uintptr_t addr, uintptr_t size) {
   if (size == 0)
     return;
-  __llvm_libc::syscall_impl(SYS_munmap, addr, size);
+  __llvm_libc::syscall_impl<long>(SYS_munmap, addr, size);
 }
 
 static void set_thread_ptr(uintptr_t val) { __arm_wsr64("tpidr_el0", val); }
@@ -134,10 +134,10 @@ struct AuxEntry {
 };
 
 __attribute__((noinline)) static void do_start() {
-  auto tid = __llvm_libc::syscall_impl(SYS_gettid);
+  auto tid = __llvm_libc::syscall_impl<long>(SYS_gettid);
   if (tid <= 0)
-    __llvm_libc::syscall_impl(SYS_exit, 1);
-  __llvm_libc::main_thread_attrib.tid = tid;
+    __llvm_libc::syscall_impl<long>(SYS_exit, 1);
+  __llvm_libc::main_thread_attrib.tid = static_cast<int>(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
@@ -200,10 +200,12 @@ __attribute__((noinline)) static void do_start() {
   __llvm_libc::atexit(&__llvm_libc::call_fini_array_callbacks);
 
   __llvm_libc::call_init_array_callbacks(
-      app.args->argc, reinterpret_cast<char **>(app.args->argv),
+      static_cast<int>(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),
+  int retval = main(static_cast<int>(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
diff --git a/libc/startup/linux/riscv64/start.cpp b/libc/startup/linux/riscv64/start.cpp
index 0a78397..9835bc4 100644
--- a/libc/startup/linux/riscv64/start.cpp
+++ b/libc/startup/linux/riscv64/start.cpp
@@ -56,13 +56,13 @@ void init_tls(TLSDescriptor &tls_descriptor) {
   // 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(
+  long mmap_ret_val = __llvm_libc::syscall_impl<long>(
       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);
+    __llvm_libc::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;
   __llvm_libc::inline_memcpy(reinterpret_cast<char *>(tls_addr),
@@ -76,7 +76,7 @@ void init_tls(TLSDescriptor &tls_descriptor) {
 void cleanup_tls(uintptr_t addr, uintptr_t size) {
   if (size == 0)
     return;
-  __llvm_libc::syscall_impl(SYS_munmap, addr, size);
+  __llvm_libc::syscall_impl<long>(SYS_munmap, addr, size);
 }
 
 static void set_thread_ptr(uintptr_t val) {
@@ -127,10 +127,10 @@ __attribute__((noinline)) static void do_start() {
                   ".option norelax\n\t"
                   "lla gp, __global_pointer$\n\t"
                   ".option pop\n\t");
-  auto tid = __llvm_libc::syscall_impl(SYS_gettid);
+  auto tid = __llvm_libc::syscall_impl<long>(SYS_gettid);
   if (tid <= 0)
-    __llvm_libc::syscall_impl(SYS_exit, 1);
-  __llvm_libc::main_thread_attrib.tid = tid;
+    __llvm_libc::syscall_impl<long>(SYS_exit, 1);
+  __llvm_libc::main_thread_attrib.tid = static_cast<int>(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
@@ -193,10 +193,12 @@ __attribute__((noinline)) static void do_start() {
   __llvm_libc::atexit(&__llvm_libc::call_fini_array_callbacks);
 
   __llvm_libc::call_init_array_callbacks(
-      app.args->argc, reinterpret_cast<char **>(app.args->argv),
+      static_cast<int>(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),
+  int retval = main(static_cast<int>(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
diff --git a/libc/startup/linux/x86_64/start.cpp b/libc/startup/linux/x86_64/start.cpp
index bbcd9ae..2f9dbfd 100644
--- a/libc/startup/linux/x86_64/start.cpp
+++ b/libc/startup/linux/x86_64/start.cpp
@@ -59,13 +59,13 @@ void init_tls(TLSDescriptor &tls_descriptor) {
   // 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(
+  long mmapRetVal = __llvm_libc::syscall_impl<long>(
       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);
+    __llvm_libc::syscall_impl<long>(SYS_exit, 1);
   uintptr_t *tlsAddr = reinterpret_cast<uintptr_t *>(mmapRetVal);
 
   // x86_64 TLS faces down from the thread pointer with the first entry
@@ -84,7 +84,7 @@ void init_tls(TLSDescriptor &tls_descriptor) {
 void cleanup_tls(uintptr_t addr, uintptr_t size) {
   if (size == 0)
     return;
-  __llvm_libc::syscall_impl(SYS_munmap, addr, size);
+  __llvm_libc::syscall_impl<long>(SYS_munmap, addr, size);
 }
 
 // Sets the thread pointer to |val|. Returns true on success, false on failure.
@@ -152,10 +152,10 @@ extern "C" void _start() {
   __asm__ __volatile__("andq $0xfffffffffffffff0, %rsp\n\t");
   __asm__ __volatile__("andq $0xfffffffffffffff0, %rbp\n\t");
 
-  auto tid = __llvm_libc::syscall_impl(SYS_gettid);
+  auto tid = __llvm_libc::syscall_impl<long>(SYS_gettid);
   if (tid <= 0)
-    __llvm_libc::syscall_impl(SYS_exit, 1);
-  __llvm_libc::main_thread_attrib.tid = tid;
+    __llvm_libc::syscall_impl<long>(SYS_exit, 1);
+  __llvm_libc::main_thread_attrib.tid = static_cast<int>(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
@@ -205,7 +205,7 @@ extern "C" void _start() {
   __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::syscall_impl<long>(SYS_exit, 1);
 
   __llvm_libc::self.attrib = &__llvm_libc::main_thread_attrib;
   __llvm_libc::main_thread_attrib.atexit_callback_mgr =
@@ -218,10 +218,12 @@ extern "C" void _start() {
   __llvm_libc::atexit(&__llvm_libc::call_fini_array_callbacks);
 
   __llvm_libc::call_init_array_callbacks(
-      app.args->argc, reinterpret_cast<char **>(app.args->argv),
+      static_cast<int>(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),
+  int retval = main(static_cast<int>(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