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/DiagnosticOptions.h"
17 #include "clang/Frontend/FrontendDiagnostic.h"
18 #include "clang/Frontend/TextDiagnosticPrinter.h"
19
20 #include "llvm/Module.h"
21 #include "llvm/Config/config.h"
22 #include "llvm/ADT/OwningPtr.h"
23 #include "llvm/ADT/SmallString.h"
24 #include "llvm/Config/config.h"
25 #include "llvm/ExecutionEngine/ExecutionEngine.h"
26 #include "llvm/Support/ManagedStatic.h"
27 #include "llvm/Support/raw_ostream.h"
28 #include "llvm/Support/Host.h"
29 #include "llvm/Support/Path.h"
30 #include "llvm/Target/TargetSelect.h"
31 using namespace clang;
32 using namespace clang::driver;
33
34 // This function isn't referenced outside its translation unit, but it
35 // can't use the "static" keyword because its address is used for
36 // GetMainExecutable (since some platforms don't support taking the
37 // address of main, and some platforms can't implement GetMainExecutable
38 // without being given the address of a function in the main executable).
GetExecutablePath(const char * Argv0)39 llvm::sys::Path GetExecutablePath(const char *Argv0) {
40 // This just needs to be some symbol in the binary; C++ doesn't
41 // allow taking the address of ::main however.
42 void *MainAddr = (void*) (intptr_t) GetExecutablePath;
43 return llvm::sys::Path::GetMainExecutable(Argv0, MainAddr);
44 }
45
Execute(llvm::Module * Mod,char * const * envp)46 static int Execute(llvm::Module *Mod, char * const *envp) {
47 llvm::InitializeNativeTarget();
48
49 std::string Error;
50 llvm::OwningPtr<llvm::ExecutionEngine> EE(
51 llvm::ExecutionEngine::createJIT(Mod, &Error));
52 if (!EE) {
53 llvm::errs() << "unable to make execution engine: " << Error << "\n";
54 return 255;
55 }
56
57 llvm::Function *EntryFn = Mod->getFunction("main");
58 if (!EntryFn) {
59 llvm::errs() << "'main' function not found in module.\n";
60 return 255;
61 }
62
63 // FIXME: Support passing arguments.
64 std::vector<std::string> Args;
65 Args.push_back(Mod->getModuleIdentifier());
66
67 return EE->runFunctionAsMain(EntryFn, Args, envp);
68 }
69
main(int argc,const char ** argv,char * const * envp)70 int main(int argc, const char **argv, char * const *envp) {
71 void *MainAddr = (void*) (intptr_t) GetExecutablePath;
72 llvm::sys::Path Path = GetExecutablePath(argv[0]);
73 TextDiagnosticPrinter *DiagClient =
74 new TextDiagnosticPrinter(llvm::errs(), DiagnosticOptions());
75
76 llvm::IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
77 Diagnostic Diags(DiagID, DiagClient);
78 Driver TheDriver(Path.str(), llvm::sys::getHostTriple(),
79 "a.out", /*IsProduction=*/false, /*CXXIsProduction=*/false,
80 Diags);
81 TheDriver.setTitle("clang interpreter");
82
83 // FIXME: This is a hack to try to force the driver to do something we can
84 // recognize. We need to extend the driver library to support this use model
85 // (basically, exactly one input, and the operation mode is hard wired).
86 llvm::SmallVector<const char *, 16> Args(argv, argv + argc);
87 Args.push_back("-fsyntax-only");
88 llvm::OwningPtr<Compilation> C(TheDriver.BuildCompilation(Args));
89 if (!C)
90 return 0;
91
92 // FIXME: This is copied from ASTUnit.cpp; simplify and eliminate.
93
94 // We expect to get back exactly one command job, if we didn't something
95 // failed. Extract that job from the compilation.
96 const driver::JobList &Jobs = C->getJobs();
97 if (Jobs.size() != 1 || !isa<driver::Command>(*Jobs.begin())) {
98 llvm::SmallString<256> Msg;
99 llvm::raw_svector_ostream OS(Msg);
100 C->PrintJob(OS, C->getJobs(), "; ", true);
101 Diags.Report(diag::err_fe_expected_compiler_job) << OS.str();
102 return 1;
103 }
104
105 const driver::Command *Cmd = cast<driver::Command>(*Jobs.begin());
106 if (llvm::StringRef(Cmd->getCreator().getName()) != "clang") {
107 Diags.Report(diag::err_fe_expected_clang_command);
108 return 1;
109 }
110
111 // Initialize a compiler invocation object from the clang (-cc1) arguments.
112 const driver::ArgStringList &CCArgs = Cmd->getArguments();
113 llvm::OwningPtr<CompilerInvocation> CI(new CompilerInvocation);
114 CompilerInvocation::CreateFromArgs(*CI,
115 const_cast<const char **>(CCArgs.data()),
116 const_cast<const char **>(CCArgs.data()) +
117 CCArgs.size(),
118 Diags);
119
120 // Show the invocation, with -v.
121 if (CI->getHeaderSearchOpts().Verbose) {
122 llvm::errs() << "clang invocation:\n";
123 C->PrintJob(llvm::errs(), C->getJobs(), "\n", true);
124 llvm::errs() << "\n";
125 }
126
127 // FIXME: This is copied from cc1_main.cpp; simplify and eliminate.
128
129 // Create a compiler instance to handle the actual work.
130 CompilerInstance Clang;
131 Clang.setInvocation(CI.take());
132
133 // Create the compilers actual diagnostics engine.
134 Clang.createDiagnostics(int(CCArgs.size()),const_cast<char**>(CCArgs.data()));
135 if (!Clang.hasDiagnostics())
136 return 1;
137
138 // Infer the builtin include path if unspecified.
139 if (Clang.getHeaderSearchOpts().UseBuiltinIncludes &&
140 Clang.getHeaderSearchOpts().ResourceDir.empty())
141 Clang.getHeaderSearchOpts().ResourceDir =
142 CompilerInvocation::GetResourcesPath(argv[0], MainAddr);
143
144 // Create and execute the frontend to generate an LLVM bitcode module.
145 llvm::OwningPtr<CodeGenAction> Act(new EmitLLVMOnlyAction());
146 if (!Clang.ExecuteAction(*Act))
147 return 1;
148
149 int Res = 255;
150 if (llvm::Module *Module = Act->takeModule())
151 Res = Execute(Module, envp);
152
153 // Shutdown.
154
155 llvm::llvm_shutdown();
156
157 return Res;
158 }
159