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/Basic/DiagnosticOptions.h"
12 #include "clang/Driver/Compilation.h"
13 #include "clang/Driver/Driver.h"
14 #include "clang/Driver/Tool.h"
15 #include "clang/Frontend/CompilerInstance.h"
16 #include "clang/Frontend/CompilerInvocation.h"
17 #include "clang/Frontend/FrontendDiagnostic.h"
18 #include "clang/Frontend/TextDiagnosticPrinter.h"
19 #include "llvm/ADT/SmallString.h"
20 #include "llvm/ExecutionEngine/ExecutionEngine.h"
21 #include "llvm/ExecutionEngine/JIT.h"
22 #include "llvm/IR/Module.h"
23 #include "llvm/Support/FileSystem.h"
24 #include "llvm/Support/Host.h"
25 #include "llvm/Support/ManagedStatic.h"
26 #include "llvm/Support/Path.h"
27 #include "llvm/Support/TargetSelect.h"
28 #include "llvm/Support/raw_ostream.h"
29 #include <memory>
30 using namespace clang;
31 using 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).
GetExecutablePath(const char * Argv0)38 std::string 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::fs::getMainExecutable(Argv0, MainAddr);
43 }
44
Execute(llvm::Module * Mod,char * const * envp)45 static int Execute(llvm::Module *Mod, char * const *envp) {
46 llvm::InitializeNativeTarget();
47
48 std::string Error;
49 std::unique_ptr<llvm::ExecutionEngine> EE(
50 llvm::ExecutionEngine::create(Mod, /*ForceInterpreter*/ false, &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
main(int argc,const char ** argv,char * const * envp)69 int main(int argc, const char **argv, char * const *envp) {
70 void *MainAddr = (void*) (intptr_t) GetExecutablePath;
71 std::string 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, llvm::sys::getProcessTriple(), Diags);
79 TheDriver.setTitle("clang interpreter");
80 TheDriver.setCheckInputsExist(false);
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 SmallVector<const char *, 16> Args(argv, argv + argc);
86 Args.push_back("-fsyntax-only");
87 std::unique_ptr<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 Jobs.Print(OS, "; ", 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 std::unique_ptr<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 Jobs.Print(llvm::errs(), "\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.release());
131
132 // Create the compilers actual diagnostics engine.
133 Clang.createDiagnostics();
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 std::unique_ptr<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