diff --git a/src/rustc/driver/driver.rs b/src/rustc/driver/driver.rs
index 52aa88e6cb6..369eccc6bed 100644
--- a/src/rustc/driver/driver.rs
+++ b/src/rustc/driver/driver.rs
@@ -14,6 +14,7 @@ import io::{reader_util, writer_util};
 import getopts::{optopt, optmulti, optflag, optflagopt, opt_present};
 import back::{x86, x86_64};
 import std::map::hashmap;
+import lib::llvm::llvm;
 
 enum pp_mode {ppm_normal, ppm_expanded, ppm_typed, ppm_identified,
               ppm_expanded_identified }
@@ -440,6 +441,9 @@ fn build_session_options(match: getopts::match,
         }
         debugging_opts |= this_bit;
     }
+    if debugging_opts & session::debug_llvm != 0 {
+        llvm::LLVMSetDebug(1);
+    }
 
     let output_type =
         if parse_only || no_trans {
diff --git a/src/rustc/driver/session.rs b/src/rustc/driver/session.rs
index 64ae30895c4..61ef9f73c3f 100644
--- a/src/rustc/driver/session.rs
+++ b/src/rustc/driver/session.rs
@@ -40,6 +40,7 @@ const borrowck_stats: uint = 1024u;
 const borrowck_note_pure: uint = 2048;
 const borrowck_note_loan: uint = 4096;
 const no_landing_pads: uint = 8192;
+const debug_llvm: uint = 16384;
 
 fn debugging_opts_map() -> ~[(~str, ~str, uint)] {
     ~[(~"ppregions", ~"prettyprint regions with \
@@ -61,7 +62,8 @@ fn debugging_opts_map() -> ~[(~str, ~str, uint)] {
      (~"borrowck-note-loan", ~"note where loans are req'd",
       borrowck_note_loan),
      (~"no-landing-pads", ~"omit landing pads for unwinding",
-      no_landing_pads)
+      no_landing_pads),
+     (~"debug-llvm", ~"enable debug output from LLVM", debug_llvm)
     ]
 }
 
diff --git a/src/rustc/lib/llvm.rs b/src/rustc/lib/llvm.rs
index 376012dcf4e..7dbefa8e498 100644
--- a/src/rustc/lib/llvm.rs
+++ b/src/rustc/lib/llvm.rs
@@ -969,6 +969,9 @@ extern mod llvm {
 
     fn LLVMConstNamedStruct(S: TypeRef, ConstantVals: *ValueRef,
                             Count: c_uint) -> ValueRef;
+
+    /** Enables LLVM debug output. */
+    fn LLVMSetDebug(Enabled: c_int);
 }
 
 fn SetInstructionCallConv(Instr: ValueRef, CC: CallConv) {
diff --git a/src/rustllvm/RustWrapper.cpp b/src/rustllvm/RustWrapper.cpp
index a9f759b26aa..4a927744f07 100644
--- a/src/rustllvm/RustWrapper.cpp
+++ b/src/rustllvm/RustWrapper.cpp
@@ -27,6 +27,7 @@
 #include "llvm/Support/SourceMgr.h"
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/Support/Host.h"
+#include "llvm/Support/Debug.h"
 #include "llvm-c/Core.h"
 #include "llvm-c/BitReader.h"
 #include "llvm-c/Object.h"
@@ -185,3 +186,7 @@ extern "C" LLVMValueRef LLVMBuildAtomicRMW(LLVMBuilderRef B,
                                            unwrap(target), unwrap(source),
                                            order));
 }
+
+extern "C" void LLVMSetDebug(int Enabled) {
+  DebugFlag = Enabled;
+}
diff --git a/src/rustllvm/rustllvm.def.in b/src/rustllvm/rustllvm.def.in
index f3a3d7f4f23..64b560999be 100644
--- a/src/rustllvm/rustllvm.def.in
+++ b/src/rustllvm/rustllvm.def.in
@@ -528,6 +528,7 @@ LLVMSetAlignment
 LLVMSetCleanup
 LLVMSetCurrentDebugLocation
 LLVMSetDataLayout
+LLVMSetDebug
 LLVMSetFunctionCallConv
 LLVMSetGC
 LLVMSetGlobalConstant