diff --git a/configure b/configure
index 726d2a1e84e..6314fecdc11 100755
--- a/configure
+++ b/configure
@@ -253,6 +253,7 @@ opt docs     1 "build documentation"
 opt optimize 1 "build optimized rust code"
 opt mingw-cross 0 "cross-compile for win32 using mingw"
 opt clang 0 "prefer gcc to clang for building the runtime"
+opt debug-llvm "build LLVM in debug mode"
 valopt prefix "/usr/local" "set installation prefix"
 valopt llvm-root "" "set LLVM root"
 valopt target-triples "" "LLVM target triples (defaults to host if unset)"
@@ -433,15 +434,22 @@ do
 	step_msg "configuring LLVM for $t"
 
 	LLVM_BUILD_DIR=$CFG_BUILD_DIR/llvm/$t
-        # Just use LLVM straight from its build directory to
-        # avoid 'make install' time
-	LLVM_INST_DIR=$LLVM_BUILD_DIR/Release+Asserts
 
 	LLVM_TARGETS="--enable-targets=x86,x86_64"
 	LLVM_BUILD="--build=$t"
 	LLVM_HOST="--host=$t"
 	LLVM_TARGET="--target=$t"
-	LLVM_OPTS="--enable-optimized --disable-docs"
+    if [ -z "$CFG_ENABLE_DEBUG_LLVM" ]
+    then
+        LLVM_DBG_OPTS=""
+        # Just use LLVM straight from its build directory to
+        # avoid 'make install' time
+	    LLVM_INST_DIR=$LLVM_BUILD_DIR/Debug+Asserts
+    else
+        LLVM_DBG_OPTS="--enabled-optimized"
+	    LLVM_INST_DIR=$LLVM_BUILD_DIR/Release+Asserts
+    fi
+	LLVM_OPTS="$LLVM_DBG_OPTS --disable-docs"
 
 	LLVM_CXX_32="g++ -m32"
 	LLVM_CC_32="gcc -m32"
diff --git a/src/comp/middle/trans.rs b/src/comp/middle/trans.rs
index 18f313e0911..efef85337fc 100644
--- a/src/comp/middle/trans.rs
+++ b/src/comp/middle/trans.rs
@@ -3851,23 +3851,31 @@ fn trans_c_stack_native_call(bcx: @block_ctxt, f: @ast::expr,
     check type_has_static_size(ccx, ret_ty);
     let llretty = type_of(ccx, f.span, ret_ty);
 
-    // Allocate the argument bundle.
-    let llargbundlety = T_struct(llargtys + [llretty]);
-    let llargbundlesz = llsize_of(ccx, llargbundlety);
-    let llrawargbundle = Call(bcx, ccx.upcalls.alloc_c_stack,
-                              [llargbundlesz]);
-    let llargbundle = PointerCast(bcx, llrawargbundle, T_ptr(llargbundlety));
-
-    // Translate arguments and store into bundle.
+    // Translate arguments.
+    // n.b.: We must do this before allocating the argument
+    // bundle in order to avoid problems with nested function calls.
     let (to_zero, to_revoke) = ([], []);
     let i = 0u, n = vec::len(args);
+    let llargs = [];
     while i < n {
         let ty_arg = fn_arg_tys[i];
         let arg = args[i];
         let llargty = llargtys[i];
         let r = trans_arg_expr(bcx, ty_arg, llargty, to_zero, to_revoke, arg);
         bcx = r.bcx;
-        store_inbounds(bcx, r.val, llargbundle, [0, i as int]);
+        llargs += [r.val];
+        i += 1u;
+    }
+
+    // Allocate the argument bundle and store arguments.
+    let llargbundlety = T_struct(llargtys + [llretty]);
+    let llargbundlesz = llsize_of(ccx, llargbundlety);
+    let llrawargbundle = Call(bcx, ccx.upcalls.alloc_c_stack,
+                              [llargbundlesz]);
+    let llargbundle = PointerCast(bcx, llrawargbundle, T_ptr(llargbundlety));
+    i = 0u;
+    while i < n {
+        store_inbounds(bcx, llargs[i], llargbundle, [0, i as int]);
         i += 1u;
     }