Use stack probes instead of segmented stack support on x86

Fixes rust-lang#13259 and rust-lang#14742

Author: Zoxc

src/librustc/middle/trans/base.rs

@@ -210,7 +210,9 @@ pub fn decl_fn(ccx: &CrateContext, name: &str, cc: llvm::CallConv,
     // Function addresses in Rust are never significant, allowing functions to be merged.
     llvm::SetUnnamedAddr(llfn, true);
 
-    if ccx.is_split_stack_supported() {
+    if ccx.is_probe_stack_supported() {
+        set_probe_stack(llfn);
+    } else if ccx.is_split_stack_supported() {
         set_split_stack(llfn);
     }
 
@@ -478,6 +480,12 @@ pub fn set_always_inline(f: ValueRef) {
     llvm::SetFunctionAttribute(f, llvm::AlwaysInlineAttribute)
 }
 
+pub fn set_probe_stack(f: ValueRef) {
+    "probe-stack".with_c_str(|buf| {
+        unsafe { llvm::LLVMAddFunctionAttrString(f, llvm::FunctionIndex as c_uint, buf); }
+    })
+}
+
 pub fn set_split_stack(f: ValueRef) {
     "split-stack".with_c_str(|buf| {
         unsafe { llvm::LLVMAddFunctionAttrString(f, llvm::FunctionIndex as c_uint, buf); }

src/librustc/middle/trans/context.rs

@@ -286,6 +286,13 @@ impl CrateContext {
         let ref cfg = self.sess().targ_cfg;
         cfg.os != abi::OsiOS || cfg.arch != abi::Arm
     }
+
+    pub fn is_probe_stack_supported(&self) -> bool {
+        match self.sess().targ_cfg.arch {
+            abi::X86 | abi::X86_64 => true,
+            _ => false
+        }
+    }
 }
 
 fn declare_intrinsic(ccx: &CrateContext, key: & &'static str) -> Option<ValueRef> {