main.cpp revision 9d8b5fc45e48bb913dcb7f253f005418ba979534 
1//===-- examples/clang-interpreter/main.cpp - Clang C Interpreter Example -===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#include "clang/CodeGen/CodeGenAction.h"
11#include "clang/Driver/Compilation.h"
12#include "clang/Driver/Driver.h"
13#include "clang/Driver/Tool.h"
14#include "clang/Frontend/CompilerInvocation.h"
15#include "clang/Frontend/CompilerInstance.h"
16#include "clang/Frontend/FrontendDiagnostic.h"
17#include "clang/Frontend/TextDiagnosticPrinter.h"
18#include "clang/Basic/DiagnosticOptions.h"
19
20#include "llvm/Module.h"
21#include "llvm/ADT/OwningPtr.h"
22#include "llvm/ADT/SmallString.h"
23#include "llvm/ExecutionEngine/JIT.h"
24#include "llvm/ExecutionEngine/ExecutionEngine.h"
25#include "llvm/Support/ManagedStatic.h"
26#include "llvm/Support/raw_ostream.h"
27#include "llvm/Support/Host.h"
28#include "llvm/Support/Path.h"
29#include "llvm/Support/TargetSelect.h"
30using namespace clang;
31using namespace clang::driver;
32
33// This function isn't referenced outside its translation unit, but it
34// can't use the "static" keyword because its address is used for
35// GetMainExecutable (since some platforms don't support taking the
36// address of main, and some platforms can't implement GetMainExecutable
37// without being given the address of a function in the main executable).
38llvm::sys::Path GetExecutablePath(const char *Argv0) {
39  // This just needs to be some symbol in the binary; C++ doesn't
40  // allow taking the address of ::main however.
41  void *MainAddr = (void*) (intptr_t) GetExecutablePath;
42  return llvm::sys::Path::GetMainExecutable(Argv0, MainAddr);
43}
44
45static int Execute(llvm::Module *Mod, char * const *envp) {
46  llvm::InitializeNativeTarget();
47
48  std::string Error;
49  OwningPtr<llvm::ExecutionEngine> EE(
50    llvm::ExecutionEngine::createJIT(Mod, &Error));
51  if (!EE) {
52    llvm::errs() << "unable to make execution engine: " << Error << "\n";
53    return 255;
54  }
55
56  llvm::Function *EntryFn = Mod->getFunction("main");
57  if (!EntryFn) {
58    llvm::errs() << "'main' function not found in module.\n";
59    return 255;
60  }
61
62  // FIXME: Support passing arguments.
63  std::vector<std::string> Args;
64  Args.push_back(Mod->getModuleIdentifier());
65
66  return EE->runFunctionAsMain(EntryFn, Args, envp);
67}
68
69int main(int argc, const char **argv, char * const *envp) {
70  void *MainAddr = (void*) (intptr_t) GetExecutablePath;
71  llvm::sys::Path Path = GetExecutablePath(argv[0]);
72  IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
73  TextDiagnosticPrinter *DiagClient =
74    new TextDiagnosticPrinter(llvm::errs(), &*DiagOpts);
75
76  IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
77  DiagnosticsEngine Diags(DiagID, &*DiagOpts, DiagClient);
78  Driver TheDriver(Path.str(), llvm::sys::getDefaultTargetTriple(),
79                   "a.out", Diags);
80  TheDriver.setTitle("clang interpreter");
81
82  // FIXME: This is a hack to try to force the driver to do something we can
83  // recognize. We need to extend the driver library to support this use model
84  // (basically, exactly one input, and the operation mode is hard wired).
85  llvm::SmallVector<const char *, 16> Args(argv, argv + argc);
86  Args.push_back("-fsyntax-only");
87  OwningPtr<Compilation> C(TheDriver.BuildCompilation(Args));
88  if (!C)
89    return 0;
90
91  // FIXME: This is copied from ASTUnit.cpp; simplify and eliminate.
92
93  // We expect to get back exactly one command job, if we didn't something
94  // failed. Extract that job from the compilation.
95  const driver::JobList &Jobs = C->getJobs();
96  if (Jobs.size() != 1 || !isa<driver::Command>(*Jobs.begin())) {
97    SmallString<256> Msg;
98    llvm::raw_svector_ostream OS(Msg);
99    C->PrintJob(OS, C->getJobs(), "; ", true);
100    Diags.Report(diag::err_fe_expected_compiler_job) << OS.str();
101    return 1;
102  }
103
104  const driver::Command *Cmd = cast<driver::Command>(*Jobs.begin());
105  if (llvm::StringRef(Cmd->getCreator().getName()) != "clang") {
106    Diags.Report(diag::err_fe_expected_clang_command);
107    return 1;
108  }
109
110  // Initialize a compiler invocation object from the clang (-cc1) arguments.
111  const driver::ArgStringList &CCArgs = Cmd->getArguments();
112  OwningPtr<CompilerInvocation> CI(new CompilerInvocation);
113  CompilerInvocation::CreateFromArgs(*CI,
114                                     const_cast<const char **>(CCArgs.data()),
115                                     const_cast<const char **>(CCArgs.data()) +
116                                       CCArgs.size(),
117                                     Diags);
118
119  // Show the invocation, with -v.
120  if (CI->getHeaderSearchOpts().Verbose) {
121    llvm::errs() << "clang invocation:\n";
122    C->PrintJob(llvm::errs(), C->getJobs(), "\n", true);
123    llvm::errs() << "\n";
124  }
125
126  // FIXME: This is copied from cc1_main.cpp; simplify and eliminate.
127
128  // Create a compiler instance to handle the actual work.
129  CompilerInstance Clang;
130  Clang.setInvocation(CI.take());
131
132  // Create the compilers actual diagnostics engine.
133  Clang.createDiagnostics(int(CCArgs.size()),const_cast<char**>(CCArgs.data()));
134  if (!Clang.hasDiagnostics())
135    return 1;
136
137  // Infer the builtin include path if unspecified.
138  if (Clang.getHeaderSearchOpts().UseBuiltinIncludes &&
139      Clang.getHeaderSearchOpts().ResourceDir.empty())
140    Clang.getHeaderSearchOpts().ResourceDir =
141      CompilerInvocation::GetResourcesPath(argv[0], MainAddr);
142
143  // Create and execute the frontend to generate an LLVM bitcode module.
144  OwningPtr<CodeGenAction> Act(new EmitLLVMOnlyAction());
145  if (!Clang.ExecuteAction(*Act))
146    return 1;
147
148  int Res = 255;
149  if (llvm::Module *Module = Act->takeModule())
150    Res = Execute(Module, envp);
151
152  // Shutdown.
153
154  llvm::llvm_shutdown();
155
156  return Res;
157}
158