Question

理念

您好！我想创建一个程序，它将生成Haskell Core并将使用GHC API将其进一步编译成可执行文件。但在我做之前，我想构建一个非常基本的例子，展示如何将Haskell源代码编译成CORE然后再编译到二进制文件中。

问题

我已经阅读了很多文档并尝试过GHC Api的许多方法，但是现在没有成功。我从Official GHC Api introduction开始并成功编译了示例。这些示例显示了以下函数的用法：parseModule，typecheckModule，desugarModule，getNamesInScope和getModuleGraph，但不涵盖最终的编译步骤。另一方面，api中有一些函数，其名称与问题相关，如HscMain.{hscCompileOneShot, hscCompileBatch}或GHC.{compileToCoreModule, compileCoreToObj}。我尝试使用它们，但是我遇到了运行时错误，例如：

import GHC
import GHC.Paths ( libdir )
import DynFlags
targetFile = "Test.hs"

main :: IO ()
main = do
   res <- example
   return ()

example = 
    defaultErrorHandler defaultFatalMessager defaultFlushOut $ do
      runGhc (Just libdir) $ do
        dflags <- getSessionDynFlags
        let dflags' = foldl xopt_set dflags
                            [Opt_Cpp, Opt_ImplicitPrelude, Opt_MagicHash]
        setSessionDynFlags dflags'
        coreMod <- compileToCoreModule targetFile
        compileCoreToObj False coreMod "foo" "bar"
        return ()

可以使用ghc -package ghc Main.hs进行编译，并在运行时导致以下错误：

Main: panic! (the 'impossible' happened)
  (GHC version 7.8.3 for x86_64-unknown-linux):
    expectJust mkStubPaths

当然可能是错误的API使用的结果，特别是因为行compileCoreToObj False coreMod "foo" "bar"，字符串只是随机的，因为文档没有对它们说太多。如果我们查看源代码，似乎第一个是输出名称，第二个是＆＃34; extCore_filename＆＃34;，无论它是什么。

另一个令人担忧的问题是compileCoreToObj函数旁边的文档中的注释：

[...]到目前为止，仅使用一个独立的模块进行了测试。

但我希望它不会引入任何进一步的问题。

问题

创建此解决方案的最佳方法是什么？我们如何创建一个最小的工作示例，它将加载haskell源，将它们编译到CORE中，然后将核心编译为最终的可执行文件（使用GHC API）。需要通过自定义CORE进一步替换中间步骤。

作为一个侧面问题 - 目前可能为GHC提供外部核心文件，或者此功能尚未实现，我将不得不使用GHC.Api手动构建Core（与Compiling to GHC Core相关））

更新

我终于能够创建一个小例子，允许加载模块并将其编译为.hi和.o文件。这不是问题的解决方案，因为它不允许我替换CORE并且它不会将目标文件链接到可执行文件中：

import GHC
import GHC.Paths ( libdir )
import DynFlags
import Linker
import Module
targetFile = "Test.hs"

main :: IO ()
main = do
   res <- example
   return ()

example = 
    defaultErrorHandler defaultFatalMessager defaultFlushOut $ do
      runGhc (Just libdir) $ do
        dflags <- getSessionDynFlags
        let dflags2 = dflags { ghcLink   = LinkBinary
                             , hscTarget = HscAsm
                             }
        let dflags' = foldl xopt_set dflags2
                            [Opt_Cpp, Opt_ImplicitPrelude, Opt_MagicHash]
        setSessionDynFlags dflags'
        setTargets =<< sequence [guessTarget "Test.hs" Nothing]

        load LoadAllTargets
        return ()

Answer 1

生成核心的文本表示在这里不是问题，因为它可以以多种方式制作。您可以使用-fext-core标记生成.hcr个文件，并使用例如extcore。还有其他可以转储核心的软件包，例如ghc-core或ghc-core-html。

这里的主要问题是将ghc-core加载到ghc。据我所知，它得到了支持，但现在却没有，因为使用它的兴趣很低，随着时间的推移它已经过时了。

我们可以尝试的最好的事情是在ghc内部挖掘更多内容，找到使用ghc-core的地方并尝试在那里修改它。也许我们也可以尝试创建ghc plugin并使用它来修改核心。

Answer 2

简短回答：一旦你需要对象文件，你可以使用你选择的c编译器来编译一个主存根并链接到一个可执行文件。

如果您有目标文件，那么GHC将执行的最后步骤是在链接器和C编译器中完成的。例如，通过为简单的hello_world设置-verbose标志和-keep-tmp文件，在构建对象之后，我的最后三个步骤是：

'/usr/bin/gcc' '-fno-stack-protector' '-Wl,--hash-size=31' '-Wl,--reduce-memory-overheads' '-c' '/tmp/ghc29076_0/ghc29076_0.c' '-o' '/tmp/ghc29076_0/ghc29076_0.o' '-DTABLES_NEXT_TO_CODE' '-I/usr/lib/ghc/include'
*** C Compiler:
'/usr/bin/gcc' '-fno-stack-protector' '-Wl,--hash-size=31' '-Wl,--reduce-memory-overheads' '-c' '/tmp/ghc29076_0/ghc29076_0.s' '-o' '/tmp/ghc29076_0/ghc29076_1.o' '-DTABLES_NEXT_TO_CODE' '-I/usr/lib/ghc/include'
*** Linker:
'/usr/bin/gcc' '-fno-stack-protector' '-Wl,--hash-size=31' '-Wl,--reduce-memory-overheads' '-o' 'hello' 'hello.o' '-L/usr/lib/ghc/base-4.6.0.1' '-L/usr/lib/ghc/integer-gmp-0.5.0.0' '-L/usr/lib/ghc/ghc-prim-0.3.0.0' '-L/usr/lib/ghc' '/tmp/ghc29076_0/ghc29076_0.o' '/tmp/ghc29076_0/ghc29076_1.o' '-lHSbase-4.6.0.1' '-lHSinteger-gmp-0.5.0.0' '-lgmp' '-lHSghc-prim-0.3.0.0' '-lHSrts' '-lffi' '-lm' '-lrt' '-ldl' '-u' 'ghczmprim_GHCziTypes_Izh_static_info' '-u' 'ghczmprim_GHCziTypes_Czh_static_info' '-u' 'ghczmprim_GHCziTypes_Fzh_static_info' '-u' 'ghczmprim_GHCziTypes_Dzh_static_info' '-u' 'base_GHCziPtr_Ptr_static_info' '-u' 'ghczmprim_GHCziTypes_Wzh_static_info' '-u' 'base_GHCziInt_I8zh_static_info' '-u' 'base_GHCziInt_I16zh_static_info' '-u' 'base_GHCziInt_I32zh_static_info' '-u' 'base_GHCziInt_I64zh_static_info' '-u' 'base_GHCziWord_W8zh_static_info' '-u' 'base_GHCziWord_W16zh_static_info' '-u' 'base_GHCziWord_W32zh_static_info' '-u' 'base_GHCziWord_W64zh_static_info' '-u' 'base_GHCziStable_StablePtr_static_info' '-u' 'ghczmprim_GHCziTypes_Izh_con_info' '-u' 'ghczmprim_GHCziTypes_Czh_con_info' '-u' 'ghczmprim_GHCziTypes_Fzh_con_info' '-u' 'ghczmprim_GHCziTypes_Dzh_con_info' '-u' 'base_GHCziPtr_Ptr_con_info' '-u' 'base_GHCziPtr_FunPtr_con_info' '-u' 'base_GHCziStable_StablePtr_con_info' '-u' 'ghczmprim_GHCziTypes_False_closure' '-u' 'ghczmprim_GHCziTypes_True_closure' '-u' 'base_GHCziPack_unpackCString_closure' '-u' 'base_GHCziIOziException_stackOverflow_closure' '-u' 'base_GHCziIOziException_heapOverflow_closure' '-u' 'base_ControlziExceptionziBase_nonTermination_closure' '-u' 'base_GHCziIOziException_blockedIndefinitelyOnMVar_closure' '-u' 'base_GHCziIOziException_blockedIndefinitelyOnSTM_closure' '-u' 'base_ControlziExceptionziBase_nestedAtomically_closure' '-u' 'base_GHCziWeak_runFinalizzerBatch_closure' '-u' 'base_GHCziTopHandler_flushStdHandles_closure' '-u' 'base_GHCziTopHandler_runIO_closure' '-u' 'base_GHCziTopHandler_runNonIO_closure' '-u' 'base_GHCziConcziIO_ensureIOManagerIsRunning_closure' '-u' 'base_GHCziConcziSync_runSparks_closure' '-u' 'base_GHCziConcziSignal_runHandlers_closure'

查看前两个文件显示c文件只是：

#include "Rts.h"
extern StgClosure ZCMain_main_closure;
int main(int argc, char *argv[])
{
    RtsConfig __conf = defaultRtsConfig;
    __conf.rts_opts_enabled = RtsOptsSafeOnly;
   return hs_main(argc, argv, &ZCMain_main_closure,__conf);
}

似乎不应该在项目之间做太多改变。

汇编文件是：

 .section .debug-ghc-link-info,"",@note
 .ascii "([\"-lHSbase-4.6.0.1\",\"-lHSinteger-gmp-0.5.0.0\",\"-lgmp\",\"-lHSghc-prim-0.3.0.0\",\"-lHSrts\",\"-lffi\    ",\"-lm\",\"-lrt\",\"-ldl\",\"-u\",\"ghczmprim_GHCziTypes_Izh_static_info\",\"-u\",\"ghczmprim_GHCziTypes_Czh_static    _info\",\"-u\",\"ghczmprim_GHCziTypes_Fzh_static_info\",\"-u\",\"ghczmprim_GHCziTypes_Dzh_static_info\",\"-u\",\"bas    e_GHCziPtr_Ptr_static_info\",\"-u\",\"ghczmprim_GHCziTypes_Wzh_static_info\",\"-u\",\"base_GHCziInt_I8zh_static_info    \",\"-u\",\"base_GHCziInt_I16zh_static_info\",\"-u\",\"base_GHCziInt_I32zh_static_info\",\"-u\",\"base_GHCziInt_I64z    h_static_info\",\"-u\",\"base_GHCziWord_W8zh_static_info\",\"-u\",\"base_GHCziWord_W16zh_static_info\",\"-u\",\"base    _GHCziWord_W32zh_static_info\",\"-u\",\"base_GHCziWord_W64zh_static_info\",\"-u\",\"base_GHCziStable_StablePtr_stati    c_info\",\"-u\",\"ghczmprim_GHCziTypes_Izh_con_info\",\"-u\",\"ghczmprim_GHCziTypes_Czh_con_info\",\"-u\",\"ghczmpri    m_GHCziTypes_Fzh_con_info\",\"-u\",\"ghczmprim_GHCziTypes_Dzh_con_info\",\"-u\",\"base_GHCziPtr_Ptr_con_info\",\"-u\    ",\"base_GHCziPtr_FunPtr_con_info\",\"-u\",\"base_GHCziStable_StablePtr_con_info\",\"-u\",\"ghczmprim_GHCziTypes_Fal    se_closure\",\"-u\",\"ghczmprim_GHCziTypes_True_closure\",\"-u\",\"base_GHCziPack_unpackCString_closure\",\"-u\",\"b    ase_GHCziIOziException_stackOverflow_closure\",\"-u\",\"base_GHCziIOziException_heapOverflow_closure\",\"-u\",\"base    _ControlziExceptionziBase_nonTermination_closure\",\"-u\",\"base_GHCziIOziException_blockedIndefinitelyOnMVar_closur    e\",\"-u\",\"base_GHCziIOziException_blockedIndefinitelyOnSTM_closure\",\"-u\",\"base_ControlziExceptionziBase_neste    dAtomically_closure\",\"-u\",\"base_GHCziWeak_runFinalizzerBatch_closure\",\"-u\",\"base_GHCziTopHandler_flushStdHan    dles_closure\",\"-u\",\"base_GHCziTopHandler_runIO_closure\",\"-u\",\"base_GHCziTopHandler_runNonIO_closure\",\"-u\"    ,\"base_GHCziConcziIO_ensureIOManagerIsRunning_closure\",\"-u\",\"base_GHCziConcziSync_runSparks_closure\",\"-u\",\"    base_GHCziConcziSignal_runHandlers_closure\"],[],Nothing,RtsOptsSafeOnly,False,[],[])"

嗯，这有点糟糕，但看起来这些是一些链接器标志列表，其中有一些gobbledygook最终被传递到GHC。我不确定是什么链接器未定义的所有内容，查看链接器标志将是您最大的功课。你需要修改那些标志吗？也许，也许只有依赖关系发生变化。

使用GHC API将Haskell源代码编译为CORE，将CORE编译为二进制代码

2 个答案: