1

When reading rabbitmq's rabbit.erl，it contain hipe compilation related code. 

hipe_compile() ->
    Count = length(?HIPE_WORTHY),
    io:format("HiPE compiling:  |~s|~n                 |",
              [string:copies("-", Count)]),
    T1 = erlang:now(),
    PidMRefs = [spawn_monitor(fun () -> [begin
                                             {ok, M} = hipe:c(M, [o3]),
                                             io:format("#")
                                         end || M <- Ms]
                              end) ||
                   Ms <- split(?HIPE_WORTHY, ?HIPE_PROCESSES)],
    [receive
         {'DOWN', MRef, process, _, normal} -> ok;
         {'DOWN', MRef, process, _, Reason} -> exit(Reason)
     end || {_Pid, MRef} <- PidMRefs],
    T2 = erlang:now(),
    io:format("|~n~nCompiled ~B modules in ~Bs~n",
              [Count, timer:now_diff(T2, T1) div 1000000]).

But there is no explanation about hipe in the erlang's reference doc. What's the meaning of 'o3'?

(emacs@chen-yumatoMacBook-Pro.local)51> hipe:c(xx_reader,[o3]).
{ok,xx_reader}

After I use hipe:c as above, No new compiled file can be found the in the pwd() directory? Where it is?

4

2 回答 2

3

o3表示编译器使用的优化级别。还有等级o0, o1, o2. 各级别详情如下：

   o1 = [inline_fp,pmatch,peephole],
   o2 = [icode_range,icode_ssa_const_prop,icode_ssa_copy_prop,icode_type,
         icode_inline_bifs,rtl_lcm,rtl_ssa,rtl_ssa_const_prop,spillmin_color,
         use_indexing,remove_comments,concurrent_comp,binary_opt] ++ o1,
   o3 = [{regalloc,coalescing},icode_range] ++ o2.

您可以使用hipe:help_option(Option)进一步调查不同选项的含义。例如，

3> hipe:help_option(regalloc).
regalloc - Select register allocation algorithm. Used as {regalloc, METHOD}.
  Currently available methods:
    naive - spills everything (for debugging and testing)
    linear_scan - fast; not so good if few registers available
    graph_color - slow, but gives OK performance
    coalescing - slower, tries hard to use registers
    optimistic - another variant of a coalescing allocator
ok
4> hipe:help_option(icode_range).
icode_range - Performs integer range analysis on the Icode level
ok

我认为 HiPE 是 JIT 编译，就像 Java 中使用的那样。本机部分仅在运行时可用，因此文件系统中不应有明确的表示。

另外，hipe:c确实需要一个.beam文件。例如，如果你test.erl用一些东西创建了一个，并且没有将它编译到.beam文件中，hipe:c直接调用会导致错误：

1> hipe:c(test, [o3]).
<HiPE (v 3.9.3)> EXITED with reason {cant_find_beam_file,test} @hipe:419

=ERROR REPORT==== 29-Nov-2012::17:03:02 ===
<HiPE (v 3.9.3)> Error: [hipe:418]: Cannot find test.beam file.** exception error: {hipe,419,{cant_find_beam_file,test}}
     in function  hipe:beam_file/1 (hipe.erl, line 419)
     in call from hipe:c/2 (hipe.erl, line 313)
2> c(test).
{ok,test}
3> hipe:c(test, [o3]).
{ok,test}
于 2012-11-29T09:08:41.687 回答
1

erlang的文档中有一些。见这里。但是文档确实不多。HiPE的索引页面最近才更新。

此外，您可以在 erlang shell 中查看一些帮助。

> hipe:help().
> hipe:help_options().
> hipe:help_option(Option).
于 2012-11-29T08:17:52.980 回答