Fix llvm3.3 build. Document change to code_llvm

NEWS.md

@@ -242,6 +242,8 @@ Library improvements
     * `lock` and `unlock` which operate on `ReentrantLock`. Useful to lock a stream during
       concurrent writes from multiple tasks
 
+    * `code_llvm` now outputs stripped IR without debug info or other attached metadata.
+      Use `code_llvm_raw` for the unstripped output ([#10747]).
 
 Deprecated or removed
 ---------------------

doc/stdlib/base.rst

@@ -985,6 +985,8 @@ Internals
 
    Prints the LLVM bitcodes generated for running the method matching the given generic function and type signature to :const:`STDOUT`.
 
+   All metadata and dbg.* calls are removed from the printed bitcode. Use code_llvm_raw for the full IR.
+
 .. function:: @code_llvm
 
    Evaluates the arguments to the function call, determines their types, and calls :func:`code_llvm` on the resulting expression

src/codegen.cpp

@@ -962,7 +962,6 @@ const jl_value_t *jl_dump_function_ir(void *f, bool strip_ir_metadata)
     } else {
         // make a copy of the function and strip metadata from the copy
         llvm::ValueToValueMapTy VMap;
-        std::vector<Instruction> dbgInsts;
         Function* f2 = llvm::CloneFunction(llvmf, VMap, false);
         Function::BasicBlockListType::iterator f2_bb = f2->getBasicBlockList().begin();
         // iterate over all basic blocks in the function
@@ -987,7 +986,6 @@ const jl_value_t *jl_dump_function_ir(void *f, bool strip_ir_metadata)
                 }
             }
         }
-
         f2->print(stream);
         delete f2;
     }