diff --git a/src/librustc/driver/config.rs b/src/librustc/driver/config.rs
index d80cf72bb466d..ba758b6811c7e 100644
--- a/src/librustc/driver/config.rs
+++ b/src/librustc/driver/config.rs
@@ -220,7 +220,7 @@ pub fn debugging_opts_map() -> Vec<(&'static str, &'static str, u64)> {
 /// its respective field in the struct. There are a few hand-written parsers for
 /// parsing specific types of values in this module.
 macro_rules! cgoptions(
-    ($($opt:ident : $t:ty = ($init:expr, $parse:ident, $desc:expr)),* ,) =>
+    ($($opt:ident : $t:ty = ($init:expr, $parse:ident, $desc:expr, $is_public:expr)),* ,) =>
 (
     #[deriving(Clone)]
     pub struct CodegenOptions { $(pub $opt: $t),* }
@@ -231,8 +231,8 @@ macro_rules! cgoptions(
 
     pub type CodegenSetter = fn(&mut CodegenOptions, v: Option<&str>) -> bool;
     pub static CG_OPTIONS: &'static [(&'static str, CodegenSetter,
-                                      &'static str)] =
-        &[ $( (stringify!($opt), cgsetters::$opt, $desc) ),* ];
+                                      &'static str, bool)] =
+        &[ $( (stringify!($opt), cgsetters::$opt, $desc, $is_public) ),* ];
 
     mod cgsetters {
         use super::CodegenOptions;
@@ -282,37 +282,39 @@ macro_rules! cgoptions(
 
 cgoptions!(
     ar: Option<StrBuf> = (None, parse_opt_string,
-        "tool to assemble archives with"),
+        "tool to assemble archives with", true),
     linker: Option<StrBuf> = (None, parse_opt_string,
-        "system linker to link outputs with"),
+        "system linker to link outputs with", true),
     link_args: Vec<StrBuf> = (Vec::new(), parse_list,
-        "extra arguments to pass to the linker (space separated)"),
+        "extra arguments to pass to the linker (space separated)", true),
     target_cpu: StrBuf = ("generic".to_strbuf(), parse_string,
-        "select target processor (llc -mcpu=help for details)"),
+        "select target processor (llc -mcpu=help for details)", true),
     target_feature: StrBuf = ("".to_strbuf(), parse_string,
-        "target specific attributes (llc -mattr=help for details)"),
+        "target specific attributes (llc -mattr=help for details)", true),
     passes: Vec<StrBuf> = (Vec::new(), parse_list,
-        "a list of extra LLVM passes to run (space separated)"),
+        "a list of extra LLVM passes to run (space separated)", true),
     llvm_args: Vec<StrBuf> = (Vec::new(), parse_list,
-        "a list of arguments to pass to llvm (space separated)"),
+        "a list of arguments to pass to llvm (space separated)", true),
     save_temps: bool = (false, parse_bool,
-        "save all temporary output files during compilation"),
+        "save all temporary output files during compilation", true),
     no_rpath: bool = (false, parse_bool,
-        "disables setting the rpath in libs/exes"),
+        "disables setting the rpath in libs/exes", true),
     no_prepopulate_passes: bool = (false, parse_bool,
-        "don't pre-populate the pass manager with a list of passes"),
+        "don't pre-populate the pass manager with a list of passes", true),
     no_vectorize_loops: bool = (false, parse_bool,
-        "don't run the loop vectorization optimization passes"),
+        "don't run the loop vectorization optimization passes", true),
     no_vectorize_slp: bool = (false, parse_bool,
-        "don't run LLVM's SLP vectorization pass"),
+        "don't run LLVM's SLP vectorization pass", true),
     soft_float: bool = (false, parse_bool,
-        "generate software floating point library calls"),
+        "generate software floating point library calls", true),
     prefer_dynamic: bool = (false, parse_bool,
-        "prefer dynamic linking to static linking"),
+        "prefer dynamic linking to static linking", true),
     no_integrated_as: bool = (false, parse_bool,
-        "use an external assembler rather than LLVM's integrated one"),
+        "use an external assembler rather than LLVM's integrated one", true),
     relocation_model: StrBuf = ("pic".to_strbuf(), parse_string,
-         "choose the relocation model to use (llc -relocation-model for details)"),
+         "choose the relocation model to use (llc -relocation-model for details)", true),
+    no_split_stack: bool = (false, parse_bool,
+        "disable segmented stack support", false),
 )
 
 pub fn build_codegen_options(matches: &getopts::Matches) -> CodegenOptions
@@ -324,8 +326,8 @@ pub fn build_codegen_options(matches: &getopts::Matches) -> CodegenOptions
         let value = iter.next();
         let option_to_lookup = key.replace("-", "_");
         let mut found = false;
-        for &(candidate, setter, _) in CG_OPTIONS.iter() {
-            if option_to_lookup.as_slice() != candidate { continue }
+        for &(candidate, setter, _, is_public) in CG_OPTIONS.iter() {
+            if option_to_lookup.as_slice() != candidate || !is_public { continue }
             if !setter(&mut cg, value) {
                 match value {
                     Some(..) => {
diff --git a/src/librustc/driver/mod.rs b/src/librustc/driver/mod.rs
index c870ee5e8f7ac..953745f990b23 100644
--- a/src/librustc/driver/mod.rs
+++ b/src/librustc/driver/mod.rs
@@ -176,7 +176,8 @@ fn describe_debug_flags() {
 fn describe_codegen_flags() {
     println!("\nAvailable codegen options:\n");
     let mut cg = config::basic_codegen_options();
-    for &(name, parser, desc) in config::CG_OPTIONS.iter() {
+    for &(name, parser, desc, is_public) in config::CG_OPTIONS.iter() {
+        if !is_public { continue }
         // we invoke the parser function on `None` to see if this option needs
         // an argument or not.
         let (width, extra) = if parser(&mut cg, None) {
diff --git a/src/librustc/middle/trans/base.rs b/src/librustc/middle/trans/base.rs
index e208097e99b33..b4c449cfba0c7 100644
--- a/src/librustc/middle/trans/base.rs
+++ b/src/librustc/middle/trans/base.rs
@@ -165,11 +165,11 @@ impl<'a> Drop for StatRecorder<'a> {
 }
 
 // only use this for foreign function ABIs and glue, use `decl_rust_fn` for Rust functions
-fn decl_fn(llmod: ModuleRef, name: &str, cc: lib::llvm::CallConv,
+fn decl_fn(ccx: &CrateContext, name: &str, cc: lib::llvm::CallConv,
            ty: Type, output: ty::t) -> ValueRef {
     let llfn: ValueRef = name.with_c_str(|buf| {
         unsafe {
-            llvm::LLVMGetOrInsertFunction(llmod, buf, ty.to_ref())
+            llvm::LLVMGetOrInsertFunction(ccx.llmod, buf, ty.to_ref())
         }
     });
 
@@ -193,22 +193,25 @@ fn decl_fn(llmod: ModuleRef, name: &str, cc: lib::llvm::CallConv,
     lib::llvm::SetFunctionCallConv(llfn, cc);
     // Function addresses in Rust are never significant, allowing functions to be merged.
     lib::llvm::SetUnnamedAddr(llfn, true);
-    set_split_stack(llfn);
+
+    if !ccx.sess().opts.cg.no_split_stack {
+        set_split_stack(llfn);
+    }
 
     llfn
 }
 
 // only use this for foreign function ABIs and glue, use `decl_rust_fn` for Rust functions
-pub fn decl_cdecl_fn(llmod: ModuleRef,
+pub fn decl_cdecl_fn(ccx: &CrateContext,
                      name: &str,
                      ty: Type,
                      output: ty::t) -> ValueRef {
-    decl_fn(llmod, name, lib::llvm::CCallConv, ty, output)
+    decl_fn(ccx, name, lib::llvm::CCallConv, ty, output)
 }
 
 // only use this for foreign function ABIs and glue, use `get_extern_rust_fn` for Rust functions
 pub fn get_extern_fn(externs: &mut ExternMap,
-                     llmod: ModuleRef,
+                     ccx: &CrateContext,
                      name: &str,
                      cc: lib::llvm::CallConv,
                      ty: Type,
@@ -218,7 +221,7 @@ pub fn get_extern_fn(externs: &mut ExternMap,
         Some(n) => return *n,
         None => {}
     }
-    let f = decl_fn(llmod, name, cc, ty, output);
+    let f = decl_fn(ccx, name, cc, ty, output);
     externs.insert(name.to_strbuf(), f);
     f
 }
@@ -246,7 +249,7 @@ pub fn decl_rust_fn(ccx: &CrateContext, has_env: bool,
     use middle::ty::{BrAnon, ReLateBound};
 
     let llfty = type_of_rust_fn(ccx, has_env, inputs, output);
-    let llfn = decl_cdecl_fn(ccx.llmod, name, llfty, output);
+    let llfn = decl_cdecl_fn(ccx, name, llfty, output);
 
     let uses_outptr = type_of::return_uses_outptr(ccx, output);
     let offset = if uses_outptr { 1 } else { 0 };
@@ -512,7 +515,7 @@ pub fn get_res_dtor(ccx: &CrateContext,
         let llty = type_of_dtor(ccx, class_ty);
 
         get_extern_fn(&mut *ccx.externs.borrow_mut(),
-                      ccx.llmod,
+                      ccx,
                       name.as_slice(),
                       lib::llvm::CCallConv,
                       llty,
@@ -1735,7 +1738,7 @@ pub fn register_fn_llvmty(ccx: &CrateContext,
                           output: ty::t) -> ValueRef {
     debug!("register_fn_llvmty id={} sym={}", node_id, sym);
 
-    let llfn = decl_fn(ccx.llmod, sym.as_slice(), cc, fn_ty, output);
+    let llfn = decl_fn(ccx, sym.as_slice(), cc, fn_ty, output);
     finish_register_fn(ccx, sp, sym, node_id, llfn);
     llfn
 }
@@ -1767,7 +1770,7 @@ pub fn create_entry_wrapper(ccx: &CrateContext,
         let llfty = Type::func([ccx.int_type, Type::i8p(ccx).ptr_to()],
                                &ccx.int_type);
 
-        let llfn = decl_cdecl_fn(ccx.llmod, "main", llfty, ty::mk_nil());
+        let llfn = decl_cdecl_fn(ccx, "main", llfty, ty::mk_nil());
         let llbb = "top".with_c_str(|buf| {
             unsafe {
                 llvm::LLVMAppendBasicBlockInContext(ccx.llcx, llfn, buf)
diff --git a/src/librustc/middle/trans/cleanup.rs b/src/librustc/middle/trans/cleanup.rs
index 68e66724d0c26..6258909e0f1de 100644
--- a/src/librustc/middle/trans/cleanup.rs
+++ b/src/librustc/middle/trans/cleanup.rs
@@ -680,7 +680,7 @@ impl<'a> CleanupHelperMethods<'a> for FunctionContext<'a> {
                     Some(llpersonality) => llpersonality,
                     None => {
                         let fty = Type::variadic_func(&[], &Type::i32(self.ccx));
-                        let f = base::decl_cdecl_fn(self.ccx.llmod,
+                        let f = base::decl_cdecl_fn(self.ccx,
                                                     "rust_eh_personality",
                                                     fty,
                                                     ty::mk_i32());
diff --git a/src/librustc/middle/trans/context.rs b/src/librustc/middle/trans/context.rs
index a876c68d443db..2dc750f52df0d 100644
--- a/src/librustc/middle/trans/context.rs
+++ b/src/librustc/middle/trans/context.rs
@@ -279,14 +279,14 @@ fn declare_intrinsic(ccx: &CrateContext, key: & &'static str) -> Option<ValueRef
     macro_rules! ifn (
         ($name:expr fn() -> $ret:expr) => (
             if *key == $name {
-                let f = base::decl_cdecl_fn(ccx.llmod, $name, Type::func([], &$ret), ty::mk_nil());
+                let f = base::decl_cdecl_fn(ccx, $name, Type::func([], &$ret), ty::mk_nil());
                 ccx.intrinsics.borrow_mut().insert($name, f.clone());
                 return Some(f);
             }
         );
         ($name:expr fn($($arg:expr),*) -> $ret:expr) => (
             if *key == $name {
-                let f = base::decl_cdecl_fn(ccx.llmod, $name,
+                let f = base::decl_cdecl_fn(ccx, $name,
                                   Type::func([$($arg),*], &$ret), ty::mk_nil());
                 ccx.intrinsics.borrow_mut().insert($name, f.clone());
                 return Some(f);
@@ -418,7 +418,7 @@ fn declare_intrinsic(ccx: &CrateContext, key: & &'static str) -> Option<ValueRef
                 // The `if key == $name` is already in ifn!
                 ifn!($name fn($($arg),*) -> $ret);
             } else if *key == $name {
-                let f = base::decl_cdecl_fn(ccx.llmod, stringify!($cname),
+                let f = base::decl_cdecl_fn(ccx, stringify!($cname),
                                       Type::func([$($arg),*], &$ret),
                                       ty::mk_nil());
                 ccx.intrinsics.borrow_mut().insert($name, f.clone());
diff --git a/src/librustc/middle/trans/foreign.rs b/src/librustc/middle/trans/foreign.rs
index e08ab33808ac9..47b532e5b2a5b 100644
--- a/src/librustc/middle/trans/foreign.rs
+++ b/src/librustc/middle/trans/foreign.rs
@@ -228,7 +228,7 @@ pub fn register_foreign_item_fn(ccx: &CrateContext, abi: Abi, fty: ty::t,
     let llfn_ty = lltype_for_fn_from_foreign_types(ccx, &tys);
 
     let llfn = base::get_extern_fn(&mut *ccx.externs.borrow_mut(),
-                                   ccx.llmod,
+                                   ccx,
                                    name,
                                    cc,
                                    llfn_ty,
diff --git a/src/librustc/middle/trans/glue.rs b/src/librustc/middle/trans/glue.rs
index c103a44aa7543..409b0bdad434b 100644
--- a/src/librustc/middle/trans/glue.rs
+++ b/src/librustc/middle/trans/glue.rs
@@ -459,7 +459,7 @@ fn declare_generic_glue(ccx: &CrateContext, t: ty::t, llfnty: Type,
         t,
         format!("glue_{}", name).as_slice());
     debug!("{} is for type {}", fn_nm, ppaux::ty_to_str(ccx.tcx(), t));
-    let llfn = decl_cdecl_fn(ccx.llmod,
+    let llfn = decl_cdecl_fn(ccx,
                              fn_nm.as_slice(),
                              llfnty,
                              ty::mk_nil());