rustc: Enable segmented stacks in LLVM when --stack-growth is on

Author: pcwalton

src/comp/back/link.rs

@@ -91,6 +91,7 @@ mod write {
     fn run_passes(sess: session::session, llmod: ModuleRef, output: str) {
         let opts = sess.get_opts();
         if opts.time_llvm_passes { llvm::LLVMRustEnableTimePasses(); }
+        if opts.stack_growth { llvm::LLVMRustEnableSegmentedStacks(); }
         link_intrinsics(sess, llmod);
         let pm = mk_pass_manager();
         let td = mk_target_data(x86::get_data_layout());

src/comp/lib/llvm.rs

@@ -868,6 +868,8 @@ native "c-stack-cdecl" mod llvm = "rustllvm" {
 
     /** Turn on LLVM pass-timing. */
     fn LLVMRustEnableTimePasses();
+    /** Turn on LLVM segmented stacks. */
+    fn LLVMRustEnableSegmentedStacks();
 
     /** Print the pass timings since static dtors aren't picking them up. */
     fn LLVMRustPrintPassTimings();

src/rustllvm/RustWrapper.cpp

@@ -123,3 +123,9 @@ extern "C" void LLVMRustPrintPassTimings() {
   raw_fd_ostream OS (2, false); // stderr.
   TimerGroup::printAll(OS);
 }
+
+extern bool llvm::EnableSegmentedStacks;
+extern "C" void LLVMRustEnableSegmentedStacks() {
+  EnableSegmentedStacks = true;
+}
+

src/rustllvm/rustllvm.def.in

@@ -6,6 +6,7 @@ LLVMRustGetHostTriple
 LLVMRustConstSmallInt
 LLVMRustParseBitcode
 LLVMRustPrintPassTimings
+LLVMRustEnableSegmentedStacks
 LLVMLinkModules
 LLVMCreateObjectFile
 LLVMDisposeObjectFile