1 //===--- CodeGenAction.cpp - LLVM Code Generation Frontend Action ---------===//
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/FileManager.h"
12 #include "clang/Basic/SourceManager.h"
13 #include "clang/Basic/TargetInfo.h"
14 #include "clang/AST/ASTConsumer.h"
15 #include "clang/AST/ASTContext.h"
16 #include "clang/AST/DeclGroup.h"
17 #include "clang/CodeGen/BackendUtil.h"
18 #include "clang/CodeGen/ModuleBuilder.h"
19 #include "clang/Frontend/CompilerInstance.h"
20 #include "clang/Frontend/FrontendDiagnostic.h"
21 #include "llvm/LLVMContext.h"
22 #include "llvm/Linker.h"
23 #include "llvm/Module.h"
24 #include "llvm/Pass.h"
25 #include "llvm/ADT/OwningPtr.h"
26 #include "llvm/Bitcode/ReaderWriter.h"
27 #include "llvm/Support/IRReader.h"
28 #include "llvm/Support/MemoryBuffer.h"
29 #include "llvm/Support/SourceMgr.h"
30 #include "llvm/Support/Timer.h"
31 using namespace clang;
32 using namespace llvm;
33 
34 namespace clang {
35   class BackendConsumer : public ASTConsumer {
36     virtual void anchor();
37     DiagnosticsEngine &Diags;
38     BackendAction Action;
39     const CodeGenOptions &CodeGenOpts;
40     const TargetOptions &TargetOpts;
41     const LangOptions &LangOpts;
42     raw_ostream *AsmOutStream;
43     ASTContext *Context;
44 
45     Timer LLVMIRGeneration;
46 
47     OwningPtr<CodeGenerator> Gen;
48 
49     OwningPtr<llvm::Module> TheModule, LinkModule;
50 
51   public:
52     BackendConsumer(BackendAction action, DiagnosticsEngine &_Diags,
53                     const CodeGenOptions &compopts,
54                     const TargetOptions &targetopts,
55                     const LangOptions &langopts,
56                     bool TimePasses,
57                     const std::string &infile,
58                     llvm::Module *LinkModule,
59                     raw_ostream *OS,
60                     LLVMContext &C) :
61       Diags(_Diags),
62       Action(action),
63       CodeGenOpts(compopts),
64       TargetOpts(targetopts),
65       LangOpts(langopts),
66       AsmOutStream(OS),
67       LLVMIRGeneration("LLVM IR Generation Time"),
68       Gen(CreateLLVMCodeGen(Diags, infile, compopts, C)),
69       LinkModule(LinkModule) {
70       llvm::TimePassesIsEnabled = TimePasses;
71     }
72 
73     llvm::Module *takeModule() { return TheModule.take(); }
74     llvm::Module *takeLinkModule() { return LinkModule.take(); }
75 
76     virtual void Initialize(ASTContext &Ctx) {
77       Context = &Ctx;
78 
79       if (llvm::TimePassesIsEnabled)
80         LLVMIRGeneration.startTimer();
81 
82       Gen->Initialize(Ctx);
83 
84       TheModule.reset(Gen->GetModule());
85 
86       if (llvm::TimePassesIsEnabled)
87         LLVMIRGeneration.stopTimer();
88     }
89 
90     virtual bool HandleTopLevelDecl(DeclGroupRef D) {
91       PrettyStackTraceDecl CrashInfo(*D.begin(), SourceLocation(),
92                                      Context->getSourceManager(),
93                                      "LLVM IR generation of declaration");
94 
95       if (llvm::TimePassesIsEnabled)
96         LLVMIRGeneration.startTimer();
97 
98       Gen->HandleTopLevelDecl(D);
99 
100       if (llvm::TimePassesIsEnabled)
101         LLVMIRGeneration.stopTimer();
102 
103       return true;
104     }
105 
106     virtual void HandleTranslationUnit(ASTContext &C) {
107       {
108         PrettyStackTraceString CrashInfo("Per-file LLVM IR generation");
109         if (llvm::TimePassesIsEnabled)
110           LLVMIRGeneration.startTimer();
111 
112         Gen->HandleTranslationUnit(C);
113 
114         if (llvm::TimePassesIsEnabled)
115           LLVMIRGeneration.stopTimer();
116       }
117 
118       // Silently ignore if we weren't initialized for some reason.
119       if (!TheModule)
120         return;
121 
122       // Make sure IR generation is happy with the module. This is released by
123       // the module provider.
124       llvm::Module *M = Gen->ReleaseModule();
125       if (!M) {
126         // The module has been released by IR gen on failures, do not double
127         // free.
128         TheModule.take();
129         return;
130       }
131 
132       assert(TheModule.get() == M &&
133              "Unexpected module change during IR generation");
134 
135       // Link LinkModule into this module if present, preserving its validity.
136       if (LinkModule) {
137         std::string ErrorMsg;
138         if (Linker::LinkModules(M, LinkModule.get(), Linker::PreserveSource,
139                                 &ErrorMsg)) {
140           Diags.Report(diag::err_fe_cannot_link_module)
141             << LinkModule->getModuleIdentifier() << ErrorMsg;
142           return;
143         }
144       }
145 
146       // Install an inline asm handler so that diagnostics get printed through
147       // our diagnostics hooks.
148       LLVMContext &Ctx = TheModule->getContext();
149       LLVMContext::InlineAsmDiagHandlerTy OldHandler =
150         Ctx.getInlineAsmDiagnosticHandler();
151       void *OldContext = Ctx.getInlineAsmDiagnosticContext();
152       Ctx.setInlineAsmDiagnosticHandler(InlineAsmDiagHandler, this);
153 
154       EmitBackendOutput(Diags, CodeGenOpts, TargetOpts, LangOpts,
155                         TheModule.get(), Action, AsmOutStream);
156 
157       Ctx.setInlineAsmDiagnosticHandler(OldHandler, OldContext);
158     }
159 
160     virtual void HandleTagDeclDefinition(TagDecl *D) {
161       PrettyStackTraceDecl CrashInfo(D, SourceLocation(),
162                                      Context->getSourceManager(),
163                                      "LLVM IR generation of declaration");
164       Gen->HandleTagDeclDefinition(D);
165     }
166 
167     virtual void CompleteTentativeDefinition(VarDecl *D) {
168       Gen->CompleteTentativeDefinition(D);
169     }
170 
171     virtual void HandleVTable(CXXRecordDecl *RD, bool DefinitionRequired) {
172       Gen->HandleVTable(RD, DefinitionRequired);
173     }
174 
175     static void InlineAsmDiagHandler(const llvm::SMDiagnostic &SM,void *Context,
176                                      unsigned LocCookie) {
177       SourceLocation Loc = SourceLocation::getFromRawEncoding(LocCookie);
178       ((BackendConsumer*)Context)->InlineAsmDiagHandler2(SM, Loc);
179     }
180 
181     void InlineAsmDiagHandler2(const llvm::SMDiagnostic &,
182                                SourceLocation LocCookie);
183   };
184 
185   void BackendConsumer::anchor() {}
186 }
187 
188 /// ConvertBackendLocation - Convert a location in a temporary llvm::SourceMgr
189 /// buffer to be a valid FullSourceLoc.
190 static FullSourceLoc ConvertBackendLocation(const llvm::SMDiagnostic &D,
191                                             SourceManager &CSM) {
192   // Get both the clang and llvm source managers.  The location is relative to
193   // a memory buffer that the LLVM Source Manager is handling, we need to add
194   // a copy to the Clang source manager.
195   const llvm::SourceMgr &LSM = *D.getSourceMgr();
196 
197   // We need to copy the underlying LLVM memory buffer because llvm::SourceMgr
198   // already owns its one and clang::SourceManager wants to own its one.
199   const MemoryBuffer *LBuf =
200   LSM.getMemoryBuffer(LSM.FindBufferContainingLoc(D.getLoc()));
201 
202   // Create the copy and transfer ownership to clang::SourceManager.
203   llvm::MemoryBuffer *CBuf =
204   llvm::MemoryBuffer::getMemBufferCopy(LBuf->getBuffer(),
205                                        LBuf->getBufferIdentifier());
206   FileID FID = CSM.createFileIDForMemBuffer(CBuf);
207 
208   // Translate the offset into the file.
209   unsigned Offset = D.getLoc().getPointer()  - LBuf->getBufferStart();
210   SourceLocation NewLoc =
211   CSM.getLocForStartOfFile(FID).getLocWithOffset(Offset);
212   return FullSourceLoc(NewLoc, CSM);
213 }
214 
215 
216 /// InlineAsmDiagHandler2 - This function is invoked when the backend hits an
217 /// error parsing inline asm.  The SMDiagnostic indicates the error relative to
218 /// the temporary memory buffer that the inline asm parser has set up.
219 void BackendConsumer::InlineAsmDiagHandler2(const llvm::SMDiagnostic &D,
220                                             SourceLocation LocCookie) {
221   // There are a couple of different kinds of errors we could get here.  First,
222   // we re-format the SMDiagnostic in terms of a clang diagnostic.
223 
224   // Strip "error: " off the start of the message string.
225   StringRef Message = D.getMessage();
226   if (Message.startswith("error: "))
227     Message = Message.substr(7);
228 
229   // If the SMDiagnostic has an inline asm source location, translate it.
230   FullSourceLoc Loc;
231   if (D.getLoc() != SMLoc())
232     Loc = ConvertBackendLocation(D, Context->getSourceManager());
233 
234 
235   // If this problem has clang-level source location information, report the
236   // issue as being an error in the source with a note showing the instantiated
237   // code.
238   if (LocCookie.isValid()) {
239     Diags.Report(LocCookie, diag::err_fe_inline_asm).AddString(Message);
240 
241     if (D.getLoc().isValid()) {
242       DiagnosticBuilder B = Diags.Report(Loc, diag::note_fe_inline_asm_here);
243       // Convert the SMDiagnostic ranges into SourceRange and attach them
244       // to the diagnostic.
245       for (unsigned i = 0, e = D.getRanges().size(); i != e; ++i) {
246         std::pair<unsigned, unsigned> Range = D.getRanges()[i];
247         unsigned Column = D.getColumnNo();
248         B << SourceRange(Loc.getLocWithOffset(Range.first - Column),
249                          Loc.getLocWithOffset(Range.second - Column));
250       }
251     }
252     return;
253   }
254 
255   // Otherwise, report the backend error as occurring in the generated .s file.
256   // If Loc is invalid, we still need to report the error, it just gets no
257   // location info.
258   Diags.Report(Loc, diag::err_fe_inline_asm).AddString(Message);
259 }
260 
261 //
262 
263 CodeGenAction::CodeGenAction(unsigned _Act, LLVMContext *_VMContext)
264   : Act(_Act), LinkModule(0),
265     VMContext(_VMContext ? _VMContext : new LLVMContext),
266     OwnsVMContext(!_VMContext) {}
267 
268 CodeGenAction::~CodeGenAction() {
269   TheModule.reset();
270   if (OwnsVMContext)
271     delete VMContext;
272 }
273 
274 bool CodeGenAction::hasIRSupport() const { return true; }
275 
276 void CodeGenAction::EndSourceFileAction() {
277   // If the consumer creation failed, do nothing.
278   if (!getCompilerInstance().hasASTConsumer())
279     return;
280 
281   // If we were given a link module, release consumer's ownership of it.
282   if (LinkModule)
283     BEConsumer->takeLinkModule();
284 
285   // Steal the module from the consumer.
286   TheModule.reset(BEConsumer->takeModule());
287 }
288 
289 llvm::Module *CodeGenAction::takeModule() {
290   return TheModule.take();
291 }
292 
293 llvm::LLVMContext *CodeGenAction::takeLLVMContext() {
294   OwnsVMContext = false;
295   return VMContext;
296 }
297 
298 static raw_ostream *GetOutputStream(CompilerInstance &CI,
299                                     StringRef InFile,
300                                     BackendAction Action) {
301   switch (Action) {
302   case Backend_EmitAssembly:
303     return CI.createDefaultOutputFile(false, InFile, "s");
304   case Backend_EmitLL:
305     return CI.createDefaultOutputFile(false, InFile, "ll");
306   case Backend_EmitBC:
307     return CI.createDefaultOutputFile(true, InFile, "bc");
308   case Backend_EmitNothing:
309     return 0;
310   case Backend_EmitMCNull:
311   case Backend_EmitObj:
312     return CI.createDefaultOutputFile(true, InFile, "o");
313   }
314 
315   llvm_unreachable("Invalid action!");
316 }
317 
318 ASTConsumer *CodeGenAction::CreateASTConsumer(CompilerInstance &CI,
319                                               StringRef InFile) {
320   BackendAction BA = static_cast<BackendAction>(Act);
321   OwningPtr<raw_ostream> OS(GetOutputStream(CI, InFile, BA));
322   if (BA != Backend_EmitNothing && !OS)
323     return 0;
324 
325   llvm::Module *LinkModuleToUse = LinkModule;
326 
327   // If we were not given a link module, and the user requested that one be
328   // loaded from bitcode, do so now.
329   const std::string &LinkBCFile = CI.getCodeGenOpts().LinkBitcodeFile;
330   if (!LinkModuleToUse && !LinkBCFile.empty()) {
331     std::string ErrorStr;
332 
333     llvm::MemoryBuffer *BCBuf =
334       CI.getFileManager().getBufferForFile(LinkBCFile, &ErrorStr);
335     if (!BCBuf) {
336       CI.getDiagnostics().Report(diag::err_cannot_open_file)
337         << LinkBCFile << ErrorStr;
338       return 0;
339     }
340 
341     LinkModuleToUse = getLazyBitcodeModule(BCBuf, *VMContext, &ErrorStr);
342     if (!LinkModuleToUse) {
343       CI.getDiagnostics().Report(diag::err_cannot_open_file)
344         << LinkBCFile << ErrorStr;
345       return 0;
346     }
347   }
348 
349   BEConsumer =
350       new BackendConsumer(BA, CI.getDiagnostics(),
351                           CI.getCodeGenOpts(), CI.getTargetOpts(),
352                           CI.getLangOpts(),
353                           CI.getFrontendOpts().ShowTimers, InFile,
354                           LinkModuleToUse, OS.take(), *VMContext);
355   return BEConsumer;
356 }
357 
358 void CodeGenAction::ExecuteAction() {
359   // If this is an IR file, we have to treat it specially.
360   if (getCurrentFileKind() == IK_LLVM_IR) {
361     BackendAction BA = static_cast<BackendAction>(Act);
362     CompilerInstance &CI = getCompilerInstance();
363     raw_ostream *OS = GetOutputStream(CI, getCurrentFile(), BA);
364     if (BA != Backend_EmitNothing && !OS)
365       return;
366 
367     bool Invalid;
368     SourceManager &SM = CI.getSourceManager();
369     const llvm::MemoryBuffer *MainFile = SM.getBuffer(SM.getMainFileID(),
370                                                       &Invalid);
371     if (Invalid)
372       return;
373 
374     // FIXME: This is stupid, IRReader shouldn't take ownership.
375     llvm::MemoryBuffer *MainFileCopy =
376       llvm::MemoryBuffer::getMemBufferCopy(MainFile->getBuffer(),
377                                            getCurrentFile().c_str());
378 
379     llvm::SMDiagnostic Err;
380     TheModule.reset(ParseIR(MainFileCopy, Err, *VMContext));
381     if (!TheModule) {
382       // Translate from the diagnostic info to the SourceManager location.
383       SourceLocation Loc = SM.translateFileLineCol(
384         SM.getFileEntryForID(SM.getMainFileID()), Err.getLineNo(),
385         Err.getColumnNo() + 1);
386 
387       // Get a custom diagnostic for the error. We strip off a leading
388       // diagnostic code if there is one.
389       StringRef Msg = Err.getMessage();
390       if (Msg.startswith("error: "))
391         Msg = Msg.substr(7);
392       unsigned DiagID = CI.getDiagnostics().getCustomDiagID(
393           DiagnosticsEngine::Error, Msg);
394 
395       CI.getDiagnostics().Report(Loc, DiagID);
396       return;
397     }
398 
399     EmitBackendOutput(CI.getDiagnostics(), CI.getCodeGenOpts(),
400                       CI.getTargetOpts(), CI.getLangOpts(),
401                       TheModule.get(),
402                       BA, OS);
403     return;
404   }
405 
406   // Otherwise follow the normal AST path.
407   this->ASTFrontendAction::ExecuteAction();
408 }
409 
410 //
411 
412 void EmitAssemblyAction::anchor() { }
413 EmitAssemblyAction::EmitAssemblyAction(llvm::LLVMContext *_VMContext)
414   : CodeGenAction(Backend_EmitAssembly, _VMContext) {}
415 
416 void EmitBCAction::anchor() { }
417 EmitBCAction::EmitBCAction(llvm::LLVMContext *_VMContext)
418   : CodeGenAction(Backend_EmitBC, _VMContext) {}
419 
420 void EmitLLVMAction::anchor() { }
421 EmitLLVMAction::EmitLLVMAction(llvm::LLVMContext *_VMContext)
422   : CodeGenAction(Backend_EmitLL, _VMContext) {}
423 
424 void EmitLLVMOnlyAction::anchor() { }
425 EmitLLVMOnlyAction::EmitLLVMOnlyAction(llvm::LLVMContext *_VMContext)
426   : CodeGenAction(Backend_EmitNothing, _VMContext) {}
427 
428 void EmitCodeGenOnlyAction::anchor() { }
429 EmitCodeGenOnlyAction::EmitCodeGenOnlyAction(llvm::LLVMContext *_VMContext)
430   : CodeGenAction(Backend_EmitMCNull, _VMContext) {}
431 
432 void EmitObjAction::anchor() { }
433 EmitObjAction::EmitObjAction(llvm::LLVMContext *_VMContext)
434   : CodeGenAction(Backend_EmitObj, _VMContext) {}
435