diff --git a/libc/arch-x86_64/syscalls/__arch_prctl.S b/libc/arch-x86_64/syscalls/__arch_prctl.S
index 70f284a56..0adcfd252 100644
--- a/libc/arch-x86_64/syscalls/__arch_prctl.S
+++ b/libc/arch-x86_64/syscalls/__arch_prctl.S
@@ -16,3 +16,4 @@ ENTRY(__arch_prctl)
 1:
     ret
 END(__arch_prctl)
+.hidden _C_LABEL(__arch_prctl)
diff --git a/libc/arch-x86_64/syscalls/__brk.S b/libc/arch-x86_64/syscalls/__brk.S
index a50d6cae9..6227f9d85 100644
--- a/libc/arch-x86_64/syscalls/__brk.S
+++ b/libc/arch-x86_64/syscalls/__brk.S
@@ -16,3 +16,4 @@ ENTRY(__brk)
 1:
     ret
 END(__brk)
+.hidden _C_LABEL(__brk)
diff --git a/libc/arch-x86_64/syscalls/__clone.S b/libc/arch-x86_64/syscalls/__clone.S
index c10402acf..9de9a681c 100644
--- a/libc/arch-x86_64/syscalls/__clone.S
+++ b/libc/arch-x86_64/syscalls/__clone.S
@@ -17,3 +17,4 @@ ENTRY(__clone)
 1:
     ret
 END(__clone)
+.hidden _C_LABEL(__clone)
diff --git a/libc/arch-x86_64/syscalls/__epoll_pwait.S b/libc/arch-x86_64/syscalls/__epoll_pwait.S
index 98f34657e..5be1f2a69 100644
--- a/libc/arch-x86_64/syscalls/__epoll_pwait.S
+++ b/libc/arch-x86_64/syscalls/__epoll_pwait.S
@@ -17,3 +17,4 @@ ENTRY(__epoll_pwait)
 1:
     ret
 END(__epoll_pwait)
+.hidden _C_LABEL(__epoll_pwait)
diff --git a/libc/arch-x86_64/syscalls/__getcpu.S b/libc/arch-x86_64/syscalls/__getcpu.S
index becdead71..c669ea69f 100644
--- a/libc/arch-x86_64/syscalls/__getcpu.S
+++ b/libc/arch-x86_64/syscalls/__getcpu.S
@@ -16,3 +16,4 @@ ENTRY(__getcpu)
 1:
     ret
 END(__getcpu)
+.hidden _C_LABEL(__getcpu)
diff --git a/libc/arch-x86_64/syscalls/__getcwd.S b/libc/arch-x86_64/syscalls/__getcwd.S
index aed2293c2..dd34d1963 100644
--- a/libc/arch-x86_64/syscalls/__getcwd.S
+++ b/libc/arch-x86_64/syscalls/__getcwd.S
@@ -16,3 +16,4 @@ ENTRY(__getcwd)
 1:
     ret
 END(__getcwd)
+.hidden _C_LABEL(__getcwd)
diff --git a/libc/arch-x86_64/syscalls/__getpriority.S b/libc/arch-x86_64/syscalls/__getpriority.S
index 4e7cdc702..588f7fe2f 100644
--- a/libc/arch-x86_64/syscalls/__getpriority.S
+++ b/libc/arch-x86_64/syscalls/__getpriority.S
@@ -16,3 +16,4 @@ ENTRY(__getpriority)
 1:
     ret
 END(__getpriority)
+.hidden _C_LABEL(__getpriority)
diff --git a/libc/arch-x86_64/syscalls/__ioctl.S b/libc/arch-x86_64/syscalls/__ioctl.S
index 384cb446a..264ffa44f 100644
--- a/libc/arch-x86_64/syscalls/__ioctl.S
+++ b/libc/arch-x86_64/syscalls/__ioctl.S
@@ -16,3 +16,4 @@ ENTRY(__ioctl)
 1:
     ret
 END(__ioctl)
+.hidden _C_LABEL(__ioctl)
diff --git a/libc/arch-x86_64/syscalls/__openat.S b/libc/arch-x86_64/syscalls/__openat.S
index 022bf7fb6..36f7ddc1d 100644
--- a/libc/arch-x86_64/syscalls/__openat.S
+++ b/libc/arch-x86_64/syscalls/__openat.S
@@ -17,3 +17,4 @@ ENTRY(__openat)
 1:
     ret
 END(__openat)
+.hidden _C_LABEL(__openat)
diff --git a/libc/arch-x86_64/syscalls/__ppoll.S b/libc/arch-x86_64/syscalls/__ppoll.S
index c6c055ba9..a92dfe502 100644
--- a/libc/arch-x86_64/syscalls/__ppoll.S
+++ b/libc/arch-x86_64/syscalls/__ppoll.S
@@ -17,3 +17,4 @@ ENTRY(__ppoll)
 1:
     ret
 END(__ppoll)
+.hidden _C_LABEL(__ppoll)
diff --git a/libc/arch-x86_64/syscalls/__pselect6.S b/libc/arch-x86_64/syscalls/__pselect6.S
index b0bb8bafe..44d5c8d2b 100644
--- a/libc/arch-x86_64/syscalls/__pselect6.S
+++ b/libc/arch-x86_64/syscalls/__pselect6.S
@@ -17,3 +17,4 @@ ENTRY(__pselect6)
 1:
     ret
 END(__pselect6)
+.hidden _C_LABEL(__pselect6)
diff --git a/libc/arch-x86_64/syscalls/__ptrace.S b/libc/arch-x86_64/syscalls/__ptrace.S
index 6c45144ff..f032f3e73 100644
--- a/libc/arch-x86_64/syscalls/__ptrace.S
+++ b/libc/arch-x86_64/syscalls/__ptrace.S
@@ -17,3 +17,4 @@ ENTRY(__ptrace)
 1:
     ret
 END(__ptrace)
+.hidden _C_LABEL(__ptrace)
diff --git a/libc/arch-x86_64/syscalls/__reboot.S b/libc/arch-x86_64/syscalls/__reboot.S
index f4d92451a..d62ebcdb2 100644
--- a/libc/arch-x86_64/syscalls/__reboot.S
+++ b/libc/arch-x86_64/syscalls/__reboot.S
@@ -17,3 +17,4 @@ ENTRY(__reboot)
 1:
     ret
 END(__reboot)
+.hidden _C_LABEL(__reboot)
diff --git a/libc/arch-x86_64/syscalls/__rt_sigaction.S b/libc/arch-x86_64/syscalls/__rt_sigaction.S
index ee50972d7..e2892bf0a 100644
--- a/libc/arch-x86_64/syscalls/__rt_sigaction.S
+++ b/libc/arch-x86_64/syscalls/__rt_sigaction.S
@@ -17,3 +17,4 @@ ENTRY(__rt_sigaction)
 1:
     ret
 END(__rt_sigaction)
+.hidden _C_LABEL(__rt_sigaction)
diff --git a/libc/arch-x86_64/syscalls/__rt_sigpending.S b/libc/arch-x86_64/syscalls/__rt_sigpending.S
index a755e2859..d683b37ce 100644
--- a/libc/arch-x86_64/syscalls/__rt_sigpending.S
+++ b/libc/arch-x86_64/syscalls/__rt_sigpending.S
@@ -16,3 +16,4 @@ ENTRY(__rt_sigpending)
 1:
     ret
 END(__rt_sigpending)
+.hidden _C_LABEL(__rt_sigpending)
diff --git a/libc/arch-x86_64/syscalls/__rt_sigprocmask.S b/libc/arch-x86_64/syscalls/__rt_sigprocmask.S
index 4f0bed5b9..236b68de2 100644
--- a/libc/arch-x86_64/syscalls/__rt_sigprocmask.S
+++ b/libc/arch-x86_64/syscalls/__rt_sigprocmask.S
@@ -17,3 +17,4 @@ ENTRY(__rt_sigprocmask)
 1:
     ret
 END(__rt_sigprocmask)
+.hidden _C_LABEL(__rt_sigprocmask)
diff --git a/libc/arch-x86_64/syscalls/__rt_sigsuspend.S b/libc/arch-x86_64/syscalls/__rt_sigsuspend.S
index 0d80dd3dc..ed45250da 100644
--- a/libc/arch-x86_64/syscalls/__rt_sigsuspend.S
+++ b/libc/arch-x86_64/syscalls/__rt_sigsuspend.S
@@ -16,3 +16,4 @@ ENTRY(__rt_sigsuspend)
 1:
     ret
 END(__rt_sigsuspend)
+.hidden _C_LABEL(__rt_sigsuspend)
diff --git a/libc/arch-x86_64/syscalls/__rt_sigtimedwait.S b/libc/arch-x86_64/syscalls/__rt_sigtimedwait.S
index fca8ffa1a..bc2fdef9d 100644
--- a/libc/arch-x86_64/syscalls/__rt_sigtimedwait.S
+++ b/libc/arch-x86_64/syscalls/__rt_sigtimedwait.S
@@ -17,3 +17,4 @@ ENTRY(__rt_sigtimedwait)
 1:
     ret
 END(__rt_sigtimedwait)
+.hidden _C_LABEL(__rt_sigtimedwait)
diff --git a/libc/arch-x86_64/syscalls/__sched_getaffinity.S b/libc/arch-x86_64/syscalls/__sched_getaffinity.S
index 9b6034c90..14765574d 100644
--- a/libc/arch-x86_64/syscalls/__sched_getaffinity.S
+++ b/libc/arch-x86_64/syscalls/__sched_getaffinity.S
@@ -16,3 +16,4 @@ ENTRY(__sched_getaffinity)
 1:
     ret
 END(__sched_getaffinity)
+.hidden _C_LABEL(__sched_getaffinity)
diff --git a/libc/arch-x86_64/syscalls/__syslog.S b/libc/arch-x86_64/syscalls/__syslog.S
index ed6a4ff48..db3a3976e 100644
--- a/libc/arch-x86_64/syscalls/__syslog.S
+++ b/libc/arch-x86_64/syscalls/__syslog.S
@@ -16,3 +16,4 @@ ENTRY(__syslog)
 1:
     ret
 END(__syslog)
+.hidden _C_LABEL(__syslog)
diff --git a/libc/arch-x86_64/syscalls/__timer_create.S b/libc/arch-x86_64/syscalls/__timer_create.S
index 97f7a569b..c4c4a2e13 100644
--- a/libc/arch-x86_64/syscalls/__timer_create.S
+++ b/libc/arch-x86_64/syscalls/__timer_create.S
@@ -16,3 +16,4 @@ ENTRY(__timer_create)
 1:
     ret
 END(__timer_create)
+.hidden _C_LABEL(__timer_create)
diff --git a/libc/arch-x86_64/syscalls/__timer_delete.S b/libc/arch-x86_64/syscalls/__timer_delete.S
index 2d4cbfb87..808884116 100644
--- a/libc/arch-x86_64/syscalls/__timer_delete.S
+++ b/libc/arch-x86_64/syscalls/__timer_delete.S
@@ -16,3 +16,4 @@ ENTRY(__timer_delete)
 1:
     ret
 END(__timer_delete)
+.hidden _C_LABEL(__timer_delete)
diff --git a/libc/arch-x86_64/syscalls/__timer_getoverrun.S b/libc/arch-x86_64/syscalls/__timer_getoverrun.S
index 508fb31c7..f5224b48e 100644
--- a/libc/arch-x86_64/syscalls/__timer_getoverrun.S
+++ b/libc/arch-x86_64/syscalls/__timer_getoverrun.S
@@ -16,3 +16,4 @@ ENTRY(__timer_getoverrun)
 1:
     ret
 END(__timer_getoverrun)
+.hidden _C_LABEL(__timer_getoverrun)
diff --git a/libc/arch-x86_64/syscalls/__timer_gettime.S b/libc/arch-x86_64/syscalls/__timer_gettime.S
index 87e6994c3..bf3efff13 100644
--- a/libc/arch-x86_64/syscalls/__timer_gettime.S
+++ b/libc/arch-x86_64/syscalls/__timer_gettime.S
@@ -16,3 +16,4 @@ ENTRY(__timer_gettime)
 1:
     ret
 END(__timer_gettime)
+.hidden _C_LABEL(__timer_gettime)
diff --git a/libc/arch-x86_64/syscalls/__timer_settime.S b/libc/arch-x86_64/syscalls/__timer_settime.S
index 5bbce2dd4..694216e28 100644
--- a/libc/arch-x86_64/syscalls/__timer_settime.S
+++ b/libc/arch-x86_64/syscalls/__timer_settime.S
@@ -17,3 +17,4 @@ ENTRY(__timer_settime)
 1:
     ret
 END(__timer_settime)
+.hidden _C_LABEL(__timer_settime)
diff --git a/libc/arch-x86_64/syscalls/__waitid.S b/libc/arch-x86_64/syscalls/__waitid.S
index 8e0f503e1..5632fb1ce 100644
--- a/libc/arch-x86_64/syscalls/__waitid.S
+++ b/libc/arch-x86_64/syscalls/__waitid.S
@@ -17,3 +17,4 @@ ENTRY(__waitid)
 1:
     ret
 END(__waitid)
+.hidden _C_LABEL(__waitid)
diff --git a/libc/tools/gensyscalls.py b/libc/tools/gensyscalls.py
index 2334e3559..578605d32 100755
--- a/libc/tools/gensyscalls.py
+++ b/libc/tools/gensyscalls.py
@@ -233,10 +233,17 @@ def make__NR_name(name):
         return "__NR_%s" % (name)
 
 
-def add_aliases(stub, syscall):
+def add_footer(pointer_length, stub, syscall):
+    # Add any aliases for this syscall.
     aliases = syscall["aliases"]
     for alias in aliases:
         stub += function_alias % { "func" : syscall["func"], "alias" : alias }
+
+    # Use hidden visibility for any functions beginning with underscores.
+    # TODO: clean up single-underscore names too.
+    if pointer_length == 64 and syscall["func"].startswith("__"):
+        stub += '.hidden _C_LABEL(' + syscall["func"] + ')\n'
+
     return stub
 
 
@@ -334,22 +341,22 @@ class State:
             syscall["__NR_name"] = make__NR_name(syscall["name"])
 
             if syscall.has_key("arm"):
-                syscall["asm-arm"] = add_aliases(arm_eabi_genstub(syscall), syscall)
+                syscall["asm-arm"] = add_footer(32, arm_eabi_genstub(syscall), syscall)
 
             if syscall.has_key("x86"):
                 if syscall["socketcall_id"] >= 0:
-                    syscall["asm-x86"] = add_aliases(x86_genstub_socketcall(syscall), syscall)
+                    syscall["asm-x86"] = add_footer(32, x86_genstub_socketcall(syscall), syscall)
                 else:
-                    syscall["asm-x86"] = add_aliases(x86_genstub(syscall), syscall)
+                    syscall["asm-x86"] = add_footer(32, x86_genstub(syscall), syscall)
             elif syscall["socketcall_id"] >= 0:
                 E("socketcall_id for dispatch syscalls is only supported for x86 in '%s'" % t)
                 return
 
             if syscall.has_key("mips"):
-                syscall["asm-mips"] = add_aliases(mips_genstub(syscall), syscall)
+                syscall["asm-mips"] = add_footer(32, mips_genstub(syscall), syscall)
 
             if syscall.has_key("x86_64"):
-                syscall["asm-x86_64"] = add_aliases(x86_64_genstub(syscall), syscall)
+                syscall["asm-x86_64"] = add_footer(64, x86_64_genstub(syscall), syscall)
 
 
     # Scan a Linux kernel asm/unistd.h file containing __NR_* constants