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/OwningPtr.h"
20 #include "llvm/ADT/SmallString.h"
21 #include "llvm/ExecutionEngine/ExecutionEngine.h"
22 #include "llvm/ExecutionEngine/JIT.h"
23 #include "llvm/IR/Module.h"
24 #include "llvm/Support/FileSystem.h"
25 #include "llvm/Support/Host.h"
26 #include "llvm/Support/ManagedStatic.h"
27 #include "llvm/Support/Path.h"
28 #include "llvm/Support/TargetSelect.h"
29 #include "llvm/Support/raw_ostream.h"
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 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
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(), "a.out", Diags);
79 TheDriver.setTitle("clang interpreter");
80
81 // FIXME: This is a hack to try to force the driver to do something we can
82 // recognize. We need to extend the driver library to support this use model
83 // (basically, exactly one input, and the operation mode is hard wired).
84 SmallVector<const char *, 16> Args(argv, argv + argc);
85 Args.push_back("-fsyntax-only");
86 OwningPtr<Compilation> C(TheDriver.BuildCompilation(Args));
87 if (!C)
88 return 0;
89
90 // FIXME: This is copied from ASTUnit.cpp; simplify and eliminate.
91
92 // We expect to get back exactly one command job, if we didn't something
93 // failed. Extract that job from the compilation.
94 const driver::JobList &Jobs = C->getJobs();
95 if (Jobs.size() != 1 || !isa<driver::Command>(*Jobs.begin())) {
96 SmallString<256> Msg;
97 llvm::raw_svector_ostream OS(Msg);
98 C->PrintJob(OS, C->getJobs(), "; ", true);
99 Diags.Report(diag::err_fe_expected_compiler_job) << OS.str();
100 return 1;
101 }
102
103 const driver::Command *Cmd = cast<driver::Command>(*Jobs.begin());
104 if (llvm::StringRef(Cmd->getCreator().getName()) != "clang") {
105 Diags.Report(diag::err_fe_expected_clang_command);
106 return 1;
107 }
108
109 // Initialize a compiler invocation object from the clang (-cc1) arguments.
110 const driver::ArgStringList &CCArgs = Cmd->getArguments();
111 OwningPtr<CompilerInvocation> CI(new CompilerInvocation);
112 CompilerInvocation::CreateFromArgs(*CI,
113 const_cast<const char **>(CCArgs.data()),
114 const_cast<const char **>(CCArgs.data()) +
115 CCArgs.size(),
116 Diags);
117
118 // Show the invocation, with -v.
119 if (CI->getHeaderSearchOpts().Verbose) {
120 llvm::errs() << "clang invocation:\n";
121 C->PrintJob(llvm::errs(), C->getJobs(), "\n", true);
122 llvm::errs() << "\n";
123 }
124
125 // FIXME: This is copied from cc1_main.cpp; simplify and eliminate.
126
127 // Create a compiler instance to handle the actual work.
128 CompilerInstance Clang;
129 Clang.setInvocation(CI.take());
130
131 // Create the compilers actual diagnostics engine.
132 Clang.createDiagnostics();
133 if (!Clang.hasDiagnostics())
134 return 1;
135
136 // Infer the builtin include path if unspecified.
137 if (Clang.getHeaderSearchOpts().UseBuiltinIncludes &&
138 Clang.getHeaderSearchOpts().ResourceDir.empty())
139 Clang.getHeaderSearchOpts().ResourceDir =
140 CompilerInvocation::GetResourcesPath(argv[0], MainAddr);
141
142 // Create and execute the frontend to generate an LLVM bitcode module.
143 OwningPtr<CodeGenAction> Act(new EmitLLVMOnlyAction());
144 if (!Clang.ExecuteAction(*Act))
145 return 1;
146
147 int Res = 255;
148 if (llvm::Module *Module = Act->takeModule())
149 Res = Execute(Module, envp);
150
151 // Shutdown.
152
153 llvm::llvm_shutdown();
154
155 return Res;
156 }
157